fix one more test

* fix edge case

* Update validator/client/sync_committee.go

Co-authored-by: Preston Van Loon <preston@prysmaticlabs.com>

Co-authored-by: Preston Van Loon <preston@prysmaticlabs.com>

WORKSPACE

@@ -197,6 +197,8 @@ filegroup(
     url = "https://github.com/eth2-clients/slashing-protection-interchange-tests/archive/b8413ca42dc92308019d0d4db52c87e9e125c4e9.tar.gz",
 )
 
+eth2_spec_version = "v1.1.0-beta.1"
+
 http_archive(
     name = "eth2_spec_tests_general",
     build_file_content = """
@@ -209,8 +211,8 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "deacc076365c727d653ac064894ecf0d1b0a675d86704dc8de271259f6a7314b",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/general.tar.gz",
+    sha256 = "e9b4cc60a3e676c6b4a9348424e44cff1ebada603ffb31b0df600dbd70e7fbf6",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/%s/general.tar.gz" % eth2_spec_version,
 )
 
 http_archive(
@@ -225,8 +227,8 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "6e9886af3d2f024e563249d70388129e28e3e92f742f289238ed9b7ec7a7f930",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/minimal.tar.gz",
+    sha256 = "cf82dc729ffe7b924f852e57d1973e1a6377c5b52acc903c953277fa9b4e6de8",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/%s/minimal.tar.gz" % eth2_spec_version,
 )
 
 http_archive(
@@ -241,8 +243,24 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "a7b3d0ffc02a567250f424d69b2474fdc9477cd56eada60af7474560b46a8527",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/mainnet.tar.gz",
+    sha256 = "6c6792375b81858037014e282d28a64b0cf12e12daf16054265c85403b8b329f",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/%s/mainnet.tar.gz" % eth2_spec_version,
+)
+
+http_archive(
+    name = "eth2_spec",
+    build_file_content = """
+filegroup(
+    name = "spec_data",
+    srcs = glob([
+        "**/*.yaml",
+    ]),
+    visibility = ["//visibility:public"],
+)
+    """,
+    sha256 = "16094dad1bab4e8ab3adb60c10e311cd1e294cd7bbf5a89505f24bebd3d0e513",
+    strip_prefix = "eth2.0-specs-" + eth2_spec_version[1:],
+    url = "https://github.com/ethereum/eth2.0-specs/archive/refs/tags/%s.tar.gz" % eth2_spec_version,
 )
 
 http_archive(

beacon-chain/blockchain/BUILD.bazel

@@ -5,6 +5,7 @@ go_library(
     srcs = [
         "chain_info.go",
         "head.go",
+        "head_sync_committee_info.go",
         "info.go",
         "init_sync_process_block.go",
         "log.go",
@@ -26,6 +27,7 @@ go_library(
     deps = [
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/cache/depositcache:go_default_library",
+        "//beacon-chain/core/altair:go_default_library",
         "//beacon-chain/core/epoch/precompute:go_default_library",
         "//beacon-chain/core/feed:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
@@ -42,6 +44,7 @@ go_library(
         "//beacon-chain/powchain:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/stategen:go_default_library",
+        "//beacon-chain/state/v2:go_default_library",
         "//cmd/beacon-chain/flags:go_default_library",
         "//proto/eth/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
@@ -56,7 +59,9 @@ go_library(
         "//shared/slotutil:go_default_library",
         "//shared/timeutils:go_default_library",
         "//shared/traceutil:go_default_library",
+        "//shared/version:go_default_library",
         "@com_github_emicklei_dot//:go_default_library",
+        "@com_github_hashicorp_golang_lru//:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",
         "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",

beacon-chain/blockchain/chain_info.go

@@ -24,6 +24,8 @@ type ChainInfoFetcher interface {
 	GenesisFetcher
 	CanonicalFetcher
 	ForkFetcher
+	TimeFetcher
+	HeadDomainFetcher
 }
 
 // TimeFetcher retrieves the Ethereum consensus data that's related to time.
@@ -48,8 +50,12 @@ type HeadFetcher interface {
 	HeadSeed(ctx context.Context, epoch types.Epoch) ([32]byte, error)
 	HeadGenesisValidatorRoot() [32]byte
 	HeadETH1Data() *ethpb.Eth1Data
+	HeadPublicKeyToValidatorIndex(ctx context.Context, pubKey [48]byte) (types.ValidatorIndex, bool)
+	HeadValidatorIndexToPublicKey(ctx context.Context, index types.ValidatorIndex) ([48]byte, error)
 	ProtoArrayStore() *protoarray.Store
 	ChainHeads() ([][32]byte, []types.Slot)
+	HeadSyncCommitteeFetcher
+	HeadDomainFetcher
 }
 
 // ForkFetcher retrieves the current fork information of the Ethereum beacon chain.

beacon-chain/blockchain/head_sync_committee_info.go

@@ -0,0 +1,188 @@
+package blockchain
+
+import (
+	"context"
+	"sync"
+
+	lru "github.com/hashicorp/golang-lru"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	core "github.com/prysmaticlabs/prysm/beacon-chain/core/state"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// HeadSyncCommitteeFetcher is the interface that wraps the head sync committee related functions.
+// The head sync committee functions return callers sync committee indices and public keys with respect to current head state.
+type HeadSyncCommitteeFetcher interface {
+	HeadCurrentSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error)
+	HeadNextSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error)
+	HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot, committeeIndex types.CommitteeIndex) ([][]byte, error)
+}
+
+// HeadDomainFetcher is the interface that wraps the head sync domain related functions.
+// The head sync committee domain functions return callers domain data with respect to slot and head state.
+type HeadDomainFetcher interface {
+	HeadSyncCommitteeDomain(ctx context.Context, slot types.Slot) ([]byte, error)
+	HeadSyncSelectionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error)
+	HeadSyncContributionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error)
+}
+
+// HeadSyncCommitteeDomain returns the head sync committee domain using current head state advanced up to `slot`.
+func (s *Service) HeadSyncCommitteeDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainSyncCommittee)
+}
+
+// HeadSyncSelectionProofDomain returns the head sync committee domain using current head state advanced up to `slot`.
+func (s *Service) HeadSyncSelectionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainSyncCommitteeSelectionProof)
+}
+
+// HeadSyncContributionProofDomain returns the head sync committee domain using current head state advanced up to `slot`.
+func (s *Service) HeadSyncContributionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainContributionAndProof)
+}
+
+// HeadCurrentSyncCommitteeIndices returns the input validator `index`'s position indices in the current sync committee with respect to `slot`.
+// Head state advanced up to `slot` is used for calculation.
+func (s *Service) HeadCurrentSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
+	if err != nil {
+		return nil, err
+	}
+	return helpers.CurrentPeriodSyncSubcommitteeIndices(headState, index)
+}
+
+// HeadNextSyncCommitteeIndices returns the input validator `index`'s position indices in the next sync committee with respect to `slot`.
+// Head state advanced up to `slot` is used for calculation.
+func (s *Service) HeadNextSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
+	if err != nil {
+		return nil, err
+	}
+	return helpers.NextPeriodSyncSubcommitteeIndices(headState, index)
+}
+
+// HeadSyncCommitteePubKeys returns the head sync committee public keys with respect to `slot` and subcommittee index `committeeIndex`.
+// Head state advanced up to `slot` is used for calculation.
+func (s *Service) HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot, committeeIndex types.CommitteeIndex) ([][]byte, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
+	if err != nil {
+		return nil, err
+	}
+
+	nextSlotEpoch := helpers.SlotToEpoch(headState.Slot() + 1)
+	currEpoch := helpers.SlotToEpoch(headState.Slot())
+
+	var syncCommittee *ethpb.SyncCommittee
+	if helpers.SyncCommitteePeriod(currEpoch) == helpers.SyncCommitteePeriod(nextSlotEpoch) {
+		syncCommittee, err = headState.CurrentSyncCommittee()
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		syncCommittee, err = headState.NextSyncCommittee()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return altair.SyncSubCommitteePubkeys(syncCommittee, committeeIndex)
+}
+
+// returns calculated domain using input `domain` and `slot`.
+func (s *Service) domainWithHeadState(ctx context.Context, slot types.Slot, domain [4]byte) ([]byte, error) {
+	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
+	if err != nil {
+		return nil, err
+	}
+	return helpers.Domain(headState.Fork(), helpers.SlotToEpoch(headState.Slot()), domain, headState.GenesisValidatorRoot())
+}
+
+// returns the head state that is advanced up to `slot`. It utilizes the cache `syncCommitteeHeadState` by retrieving using `slot` as key.
+// For the cache miss, it processes head state up to slot and fill the cache with `slot` as key.
+func (s *Service) getSyncCommitteeHeadState(ctx context.Context, slot types.Slot) (state.BeaconState, error) {
+	var headState state.BeaconState
+	var err error
+
+	// If there's already a head state exists with the request slot, we don't need to process slots.
+	cachedState := syncCommitteeHeadStateCache.get(slot)
+	if cachedState != nil && !cachedState.IsNil() {
+		syncHeadStateHit.Inc()
+		headState = cachedState
+	} else {
+		headState, err = s.HeadState(ctx)
+		if err != nil {
+			return nil, err
+		}
+		if slot > headState.Slot() {
+			headState, err = core.ProcessSlots(ctx, headState, slot)
+			if err != nil {
+				return nil, err
+			}
+		}
+		syncHeadStateMiss.Inc()
+		syncCommitteeHeadStateCache.add(slot, headState)
+	}
+
+	return headState, nil
+}
+
+var syncCommitteeHeadStateCache = newSyncCommitteeHeadState()
+
+// syncCommitteeHeadState to caches latest head state requested by the sync committee participant.
+type syncCommitteeHeadState struct {
+	cache *lru.Cache
+	lock  sync.RWMutex
+}
+
+// newSyncCommitteeHeadState initializes the lru cache for `syncCommitteeHeadState` with size of 1.
+func newSyncCommitteeHeadState() *syncCommitteeHeadState {
+	c, err := lru.New(1) // only need size of 1 to avoid redundant state copy, HTR, and process slots.
+	if err != nil {
+		panic(err)
+	}
+	return &syncCommitteeHeadState{cache: c}
+}
+
+// add `slot` as key and `state` as value onto the lru cache.
+func (c *syncCommitteeHeadState) add(slot types.Slot, state state.BeaconState) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Add(slot, state)
+}
+
+// get `state` using `slot` as key. Return nil if nothing is found.
+func (c *syncCommitteeHeadState) get(slot types.Slot) state.BeaconState {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	val, exists := c.cache.Get(slot)
+	if !exists {
+		return nil
+	}
+	if val == nil {
+		return nil
+	}
+	return val.(*stateAltair.BeaconState)
+}

beacon-chain/blockchain/head_sync_committee_info_test.go

@@ -0,0 +1,108 @@
+package blockchain
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestService_HeadCurrentSyncCommitteeIndices(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
+	c := &Service{}
+	c.head = &head{state: s}
+
+	// Process slot up to `EpochsPerSyncCommitteePeriod` so it can `ProcessSyncCommitteeUpdates`.
+	slot := uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
+	indices, err := c.HeadCurrentSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
+	require.NoError(t, err)
+
+	// NextSyncCommittee becomes CurrentSyncCommittee so it should be empty by default.
+	require.Equal(t, 0, len(indices))
+}
+
+func TestService_HeadNextSyncCommitteeIndices(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
+	c := &Service{}
+	c.head = &head{state: s}
+
+	// Process slot up to `EpochsPerSyncCommitteePeriod` so it can `ProcessSyncCommitteeUpdates`.
+	slot := uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
+	indices, err := c.HeadNextSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
+	require.NoError(t, err)
+
+	// NextSyncCommittee should be be empty after `ProcessSyncCommitteeUpdates`. Validator should get indices.
+	require.NotEqual(t, 0, len(indices))
+}
+
+func TestService_HeadSyncCommitteePubKeys(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
+	c := &Service{}
+	c.head = &head{state: s}
+
+	// Process slot up to 2 * `EpochsPerSyncCommitteePeriod` so it can run `ProcessSyncCommitteeUpdates` twice.
+	slot := uint64(2*params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
+	pubkeys, err := c.HeadSyncCommitteePubKeys(context.Background(), types.Slot(slot), 0)
+	require.NoError(t, err)
+
+	// Any subcommittee should match the subcommittee size.
+	subCommitteeSize := params.BeaconConfig().SyncCommitteeSize / params.BeaconConfig().SyncCommitteeSubnetCount
+	require.Equal(t, int(subCommitteeSize), len(pubkeys))
+}
+
+func TestService_HeadSyncCommitteeDomain(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
+	c := &Service{}
+	c.head = &head{state: s}
+
+	wanted, err := helpers.Domain(s.Fork(), helpers.SlotToEpoch(s.Slot()), params.BeaconConfig().DomainSyncCommittee, s.GenesisValidatorRoot())
+	require.NoError(t, err)
+
+	d, err := c.HeadSyncCommitteeDomain(context.Background(), 0)
+	require.NoError(t, err)
+
+	require.DeepEqual(t, wanted, d)
+}
+
+func TestService_HeadSyncContributionProofDomain(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
+	c := &Service{}
+	c.head = &head{state: s}
+
+	wanted, err := helpers.Domain(s.Fork(), helpers.SlotToEpoch(s.Slot()), params.BeaconConfig().DomainContributionAndProof, s.GenesisValidatorRoot())
+	require.NoError(t, err)
+
+	d, err := c.HeadSyncContributionProofDomain(context.Background(), 0)
+	require.NoError(t, err)
+
+	require.DeepEqual(t, wanted, d)
+}
+
+func TestService_HeadSyncSelectionProofDomain(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
+	c := &Service{}
+	c.head = &head{state: s}
+
+	wanted, err := helpers.Domain(s.Fork(), helpers.SlotToEpoch(s.Slot()), params.BeaconConfig().DomainSyncCommitteeSelectionProof, s.GenesisValidatorRoot())
+	require.NoError(t, err)
+
+	d, err := c.HeadSyncSelectionProofDomain(context.Background(), 0)
+	require.NoError(t, err)
+
+	require.DeepEqual(t, wanted, d)
+}
+
+func TestSyncCommitteeHeadStateCache_RoundTrip(t *testing.T) {
+	c := newSyncCommitteeHeadState()
+	beaconState, _ := testutil.DeterministicGenesisStateAltair(t, 100)
+	require.NoError(t, beaconState.SetSlot(100))
+	cachedState := c.get(101)
+	require.Equal(t, nil, cachedState)
+	c.add(101, beaconState)
+	cachedState = c.get(101)
+	require.DeepEqual(t, beaconState, cachedState)
+}

beacon-chain/blockchain/log.go

@@ -10,6 +10,7 @@ import (
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/timeutils"
+	"github.com/prysmaticlabs/prysm/shared/version"
 	"github.com/sirupsen/logrus"
 )
 
@@ -33,6 +34,12 @@ func logStateTransitionData(b block.BeaconBlock) {
 	if len(b.Body().VoluntaryExits()) > 0 {
 		log = log.WithField("voluntaryExits", len(b.Body().VoluntaryExits()))
 	}
+	if b.Version() == version.Altair {
+		agg, err := b.Body().SyncAggregate()
+		if err == nil {
+			log = log.WithField("syncBitsCount", agg.SyncCommitteeBits.Count())
+		}
+	}
 	log.Info("Finished applying state transition")
 }
 

beacon-chain/blockchain/metrics.go

@@ -3,15 +3,18 @@ package blockchain
 import (
 	"context"
 
+	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/version"
 )
 
 var (
@@ -107,6 +110,14 @@ var (
 			Buckets: []float64{1, 2, 3, 4, 6, 32, 64},
 		},
 	)
+	syncHeadStateMiss = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "sync_head_state_miss",
+		Help: "The number of sync head state requests that are present in the cache.",
+	})
+	syncHeadStateHit = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "sync_head_state_hit",
+		Help: "The number of sync head state requests that are not present in the cache.",
+	})
 )
 
 // reportSlotMetrics reports slot related metrics.
@@ -206,14 +217,31 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	beaconFinalizedRoot.Set(float64(bytesutil.ToLowInt64(postState.FinalizedCheckpoint().Root)))
 	currentEth1DataDepositCount.Set(float64(postState.Eth1Data().DepositCount))
 
-	// Validator participation should be viewed on the canonical chain.
-	v, b, err := precompute.New(ctx, headState)
-	if err != nil {
-		return err
-	}
-	_, b, err = precompute.ProcessAttestations(ctx, headState, v, b)
-	if err != nil {
-		return err
+	var b *precompute.Balance
+	var v []*precompute.Validator
+	var err error
+	switch headState.Version() {
+	case version.Phase0:
+		// Validator participation should be viewed on the canonical chain.
+		v, b, err = precompute.New(ctx, headState)
+		if err != nil {
+			return err
+		}
+		_, b, err = precompute.ProcessAttestations(ctx, headState, v, b)
+		if err != nil {
+			return err
+		}
+	case version.Altair:
+		v, b, err = altair.InitializeEpochValidators(ctx, headState)
+		if err != nil {
+			return err
+		}
+		_, b, err = altair.ProcessEpochParticipation(ctx, headState, b, v)
+		if err != nil {
+			return err
+		}
+	default:
+		return errors.Errorf("invalid state type provided: %T", headState.InnerStateUnsafe())
 	}
 	prevEpochActiveBalances.Set(float64(b.ActivePrevEpoch))
 	prevEpochSourceBalances.Set(float64(b.PrevEpochAttested))

beacon-chain/blockchain/service_test.go

@@ -62,6 +62,11 @@ func (mb *mockBroadcaster) BroadcastAttestation(_ context.Context, _ uint64, _ *
 	return nil
 }
 
+func (mb *mockBroadcaster) BroadcastSyncCommitteeMessage(_ context.Context, _ uint64, _ *ethpb.SyncCommitteeMessage) error {
+	mb.broadcastCalled = true
+	return nil
+}
+
 var _ p2p.Broadcaster = (*mockBroadcaster)(nil)
 
 func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {

beacon-chain/blockchain/testing/mock.go

@@ -21,7 +21,6 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/event"
@@ -42,7 +41,7 @@ type ChainService struct {
 	Genesis                     time.Time
 	ValidatorsRoot              [32]byte
 	CanonicalRoots              map[[32]byte]bool
-	Fork                        *statepb.Fork
+	Fork                        *ethpb.Fork
 	ETH1Data                    *ethpb.Eth1Data
 	DB                          db.Database
 	stateNotifier               statefeed.Notifier
@@ -52,6 +51,13 @@ type ChainService struct {
 	ForkChoiceStore             *protoarray.Store
 	VerifyBlkDescendantErr      error
 	Slot                        *types.Slot // Pointer because 0 is a useful value, so checking against it can be incorrect.
+	CurrentSyncCommitteeIndices []types.CommitteeIndex
+	NextSyncCommitteeIndices    []types.CommitteeIndex
+	SyncCommitteeDomain         []byte
+	SyncSelectionProofDomain    []byte
+	SyncContributionProofDomain []byte
+	PublicKey                   [48]byte
+	SyncCommitteePubkeys        [][]byte
 }
 
 // StateNotifier mocks the same method in the chain service.
@@ -259,7 +265,7 @@ func (s *ChainService) HeadState(context.Context) (state.BeaconState, error) {
 }
 
 // CurrentFork mocks HeadState method in chain service.
-func (s *ChainService) CurrentFork() *statepb.Fork {
+func (s *ChainService) CurrentFork() *ethpb.Fork {
 	return s.Fork
 }
 
@@ -393,3 +399,43 @@ func (s *ChainService) ChainHeads() ([][32]byte, []types.Slot) {
 		},
 		[]types.Slot{0, 1}
 }
+
+// HeadPublicKeyToValidatorIndex mocks HeadPublicKeyToValidatorIndex and always return 0 and true.
+func (s *ChainService) HeadPublicKeyToValidatorIndex(ctx context.Context, pubKey [48]byte) (types.ValidatorIndex, bool) {
+	return 0, true
+}
+
+// HeadValidatorIndexToPublicKey mocks HeadValidatorIndexToPublicKey and always return empty and nil.
+func (s *ChainService) HeadValidatorIndexToPublicKey(ctx context.Context, index types.ValidatorIndex) ([48]byte, error) {
+	return s.PublicKey, nil
+}
+
+// HeadCurrentSyncCommitteeIndices mocks HeadCurrentSyncCommitteeIndices and always return `CurrentSyncCommitteeIndices`.
+func (s *ChainService) HeadCurrentSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
+	return s.CurrentSyncCommitteeIndices, nil
+}
+
+// HeadNextSyncCommitteeIndices mocks HeadNextSyncCommitteeIndices and always return `HeadNextSyncCommitteeIndices`.
+func (s *ChainService) HeadNextSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
+	return s.NextSyncCommitteeIndices, nil
+}
+
+// HeadSyncCommitteePubKeys mocks HeadSyncCommitteePubKeys and always return empty nil.
+func (s *ChainService) HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot, committeeIndex types.CommitteeIndex) ([][]byte, error) {
+	return s.SyncCommitteePubkeys, nil
+}
+
+// HeadSyncCommitteeDomain mocks HeadSyncCommitteeDomain and always return empty nil.
+func (s *ChainService) HeadSyncCommitteeDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+	return s.SyncCommitteeDomain, nil
+}
+
+// HeadSyncSelectionProofDomain mocks HeadSyncSelectionProofDomain and always return empty nil.
+func (s *ChainService) HeadSyncSelectionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+	return s.SyncSelectionProofDomain, nil
+}
+
+// HeadSyncContributionProofDomain mocks HeadSyncContributionProofDomain and always return empty nil.
+func (s *ChainService) HeadSyncContributionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+	return s.SyncContributionProofDomain, nil
+}

beacon-chain/cache/BUILD.bazel

@@ -10,17 +10,21 @@ go_library(
         "committees.go",
         "common.go",
         "doc.go",
+        "error.go",
         "proposer_indices_type.go",
         "skip_slot_cache.go",
         "subnet_ids.go",
+        "sync_subnet_ids.go",
     ] + select({
         "//fuzz:fuzzing_enabled": [
             "committee_disabled.go",
             "proposer_indices_disabled.go",
+            "sync_committee_disabled.go",
         ],
         "//conditions:default": [
             "committee.go",
             "proposer_indices.go",
+            "sync_committee.go",
         ],
     }),
     importpath = "github.com/prysmaticlabs/prysm/beacon-chain/cache",
@@ -32,9 +36,11 @@ go_library(
     deps = [
         "//beacon-chain/state:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//shared/bytesutil:go_default_library",
         "//shared/copyutil:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/params:go_default_library",
+        "//shared/rand:go_default_library",
         "//shared/sliceutil:go_default_library",
         "@com_github_hashicorp_golang_lru//:go_default_library",
         "@com_github_patrickmn_go_cache//:go_default_library",
@@ -58,6 +64,8 @@ go_test(
         "proposer_indices_test.go",
         "skip_slot_cache_test.go",
         "subnet_ids_test.go",
+        "sync_committee_test.go",
+        "sync_subnet_ids_test.go",
     ],
     embed = [":go_default_library"],
     deps = [
@@ -66,6 +74,7 @@ go_test(
         "//proto/prysm/v1alpha1:go_default_library",
         "//shared/bytesutil:go_default_library",
         "//shared/params:go_default_library",
+        "//shared/testutil:go_default_library",
         "//shared/testutil/assert:go_default_library",
         "//shared/testutil/require:go_default_library",
         "@com_github_google_gofuzz//:go_default_library",

beacon-chain/cache/committee.go

@@ -127,6 +127,35 @@ func (c *CommitteeCache) ActiveIndices(seed [32]byte) ([]types.ValidatorIndex, e
 	return item.SortedIndices, nil
 }
 
+// ActiveBalance returns the total active balance of a given seed stored in cache.
+func (c *CommitteeCache) ActiveBalance(seed [32]byte) (uint64, error) {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	obj, exists := c.CommitteeCache.Get(key(seed))
+
+	if exists {
+		CommitteeCacheHit.Inc()
+	} else {
+		CommitteeCacheMiss.Inc()
+		return 0, ErrNonCommitteeKey
+	}
+
+	item, ok := obj.(*Committees)
+	if !ok {
+		return 0, ErrNotCommittee
+	}
+	if item == nil {
+		return 0, errors.New("item is nil")
+	}
+
+	// Return `ErrNonCommitteeKey` if active balance field doesnt exist in item.
+	if !item.ActiveBalance.Exist {
+		return 0, ErrNonCommitteeKey
+	}
+
+	return item.ActiveBalance.Total, nil
+}
+
 // ActiveIndicesCount returns the active indices count of a given seed stored in cache.
 func (c *CommitteeCache) ActiveIndicesCount(seed [32]byte) (int, error) {
 	c.lock.RLock()

beacon-chain/cache/committee_disabled.go

@@ -41,6 +41,11 @@ func (c *FakeCommitteeCache) ActiveIndicesCount(seed [32]byte) (int, error) {
 	return 0, nil
 }
 
+// ActiveBalance returns the active balance of a given seed stored in cache.
+func (c *FakeCommitteeCache) ActiveBalance(seed [32]byte) (uint64, error) {
+	return 0, nil
+}
+
 // ProposerIndices returns the proposer indices of a given seed.
 func (c *FakeCommitteeCache) ProposerIndices(seed [32]byte) ([]types.ValidatorIndex, error) {
 	return nil, nil

beacon-chain/cache/committee_test.go

@@ -88,6 +88,24 @@ func TestCommitteeCache_ActiveCount(t *testing.T) {
 	assert.Equal(t, len(item.SortedIndices), count)
 }
 
+func TestCommitteeCache_ActiveBalance(t *testing.T) {
+	cache := NewCommitteesCache()
+
+	balances := &Balance{
+		Exist: true,
+		Total: uint64(10000),
+	}
+	item := &Committees{Seed: [32]byte{'A'}, ActiveBalance: balances}
+	_, err := cache.ActiveBalance(item.Seed)
+	require.Equal(t, ErrNonCommitteeKey, err)
+
+	require.NoError(t, cache.AddCommitteeShuffledList(item))
+
+	got, err := cache.ActiveBalance(item.Seed)
+	require.NoError(t, err)
+	assert.Equal(t, balances.Total, got)
+}
+
 func TestCommitteeCache_CanRotate(t *testing.T) {
 	cache := NewCommitteesCache()
 

beacon-chain/cache/committees.go

@@ -10,10 +10,22 @@ import (
 // a Committee struct.
 var ErrNotCommittee = errors.New("object is not a committee struct")
 
+// ErrNonCommitteeKey will be returned when the committee key does not exist in cache.
+var ErrNonCommitteeKey = errors.New("committee key does not exist")
+
 // Committees defines the shuffled committees seed.
 type Committees struct {
 	CommitteeCount  uint64
 	Seed            [32]byte
 	ShuffledIndices []types.ValidatorIndex
 	SortedIndices   []types.ValidatorIndex
+	ActiveBalance   *Balance
+}
+
+// Balance tracks active balance.
+// Given default uint64 is 0, `Exist` is used to distinguish whether
+// this field has been filed.
+type Balance struct {
+	Exist bool
+	Total uint64
 }

beacon-chain/cache/error.go

@@ -0,0 +1,9 @@
+package cache
+
+import "errors"
+
+// Sync committee cache related errors
+
+// ErrNonExistingSyncCommitteeKey when sync committee key (root) does not exist in cache.
+var ErrNonExistingSyncCommitteeKey = errors.New("does not exist sync committee key")
+var errNotSyncCommitteeIndexPosition = errors.New("not syncCommitteeIndexPosition struct")

beacon-chain/cache/sync_committee.go

@@ -0,0 +1,187 @@
+// +build !libfuzzer
+
+package cache
+
+import (
+	"sync"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"k8s.io/client-go/tools/cache"
+)
+
+var (
+	maxSyncCommitteeSize = uint64(3) // Allows 3 forks to happen around `EPOCHS_PER_SYNC_COMMITTEE_PERIOD` boundary.
+
+	// SyncCommitteeCacheMiss tracks the number of committee requests that aren't present in the cache.
+	SyncCommitteeCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "sync_committee_index_cache_miss",
+		Help: "The number of committee requests that aren't present in the sync committee index cache.",
+	})
+	// SyncCommitteeCacheHit tracks the number of committee requests that are in the cache.
+	SyncCommitteeCacheHit = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "sync_committee_index_cache_hit",
+		Help: "The number of committee requests that are present in the sync committee index cache.",
+	})
+)
+
+// SyncCommitteeCache utilizes a FIFO cache to sufficiently cache validator position within sync committee.
+// It is thread safe with concurrent read write.
+type SyncCommitteeCache struct {
+	cache *cache.FIFO
+	lock  sync.RWMutex
+}
+
+// Index position of all validators in sync committee where `currentSyncCommitteeRoot` is the
+// key and `vIndexToPositionMap` is value. Inside `vIndexToPositionMap`, validator positions
+// are cached where key is the validator index and the value is the `positionInCommittee` struct.
+type syncCommitteeIndexPosition struct {
+	currentSyncCommitteeRoot [32]byte
+	vIndexToPositionMap      map[types.ValidatorIndex]*positionInCommittee
+}
+
+// Index position of individual validator of current period and next period sync committee.
+type positionInCommittee struct {
+	currentPeriod []types.CommitteeIndex
+	nextPeriod    []types.CommitteeIndex
+}
+
+// NewSyncCommittee initializes and returns a new SyncCommitteeCache.
+func NewSyncCommittee() *SyncCommitteeCache {
+	return &SyncCommitteeCache{
+		cache: cache.NewFIFO(keyFn),
+	}
+}
+
+// CurrentPeriodIndexPosition returns current period index position of a validator index with respect with
+// sync committee. If the input validator index has no assignment, an empty list will be returned.
+// If the input root does not exist in cache, ErrNonExistingSyncCommitteeKey is returned.
+// Then performing manual checking of state for index position in state is recommended.
+func (s *SyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	pos, err := s.idxPositionInCommittee(root, valIdx)
+	if err != nil {
+		return nil, err
+	}
+	if pos == nil {
+		return []types.CommitteeIndex{}, nil
+	}
+
+	return pos.currentPeriod, nil
+}
+
+// NextPeriodIndexPosition returns next period index position of a validator index in respect with sync committee.
+// If the input validator index has no assignment, an empty list will be returned.
+// If the input root does not exist in cache, ErrNonExistingSyncCommitteeKey is returned.
+// Then performing manual checking of state for index position in state is recommended.
+func (s *SyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	pos, err := s.idxPositionInCommittee(root, valIdx)
+	if err != nil {
+		return nil, err
+	}
+	if pos == nil {
+		return []types.CommitteeIndex{}, nil
+	}
+	return pos.nextPeriod, nil
+}
+
+// Helper function for `CurrentPeriodIndexPosition` and `NextPeriodIndexPosition` to return a mapping
+// of validator index to its index(s) position in the sync committee.
+func (s *SyncCommitteeCache) idxPositionInCommittee(
+	root [32]byte, valIdx types.ValidatorIndex,
+) (*positionInCommittee, error) {
+	obj, exists, err := s.cache.GetByKey(key(root))
+	if err != nil {
+		return nil, err
+	}
+	if !exists {
+		SyncCommitteeCacheMiss.Inc()
+		return nil, ErrNonExistingSyncCommitteeKey
+	}
+	item, ok := obj.(*syncCommitteeIndexPosition)
+	if !ok {
+		return nil, errNotSyncCommitteeIndexPosition
+	}
+	idxInCommittee, ok := item.vIndexToPositionMap[valIdx]
+	if !ok {
+		SyncCommitteeCacheMiss.Inc()
+		return nil, nil
+	}
+	SyncCommitteeCacheHit.Inc()
+	return idxInCommittee, nil
+}
+
+// UpdatePositionsInCommittee updates caching of validators position in sync committee in respect to
+// current epoch and next epoch. This should be called when `current_sync_committee` and `next_sync_committee`
+// change and that happens every `EPOCHS_PER_SYNC_COMMITTEE_PERIOD`.
+func (s *SyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoot [32]byte, st state.BeaconStateAltair) error {
+	csc, err := st.CurrentSyncCommittee()
+	if err != nil {
+		return err
+	}
+	positionsMap := make(map[types.ValidatorIndex]*positionInCommittee)
+	for i, pubkey := range csc.Pubkeys {
+		p := bytesutil.ToBytes48(pubkey)
+		validatorIndex, ok := st.ValidatorIndexByPubkey(p)
+		if !ok {
+			continue
+		}
+		if _, ok := positionsMap[validatorIndex]; !ok {
+			m := &positionInCommittee{currentPeriod: []types.CommitteeIndex{types.CommitteeIndex(i)}, nextPeriod: []types.CommitteeIndex{}}
+			positionsMap[validatorIndex] = m
+		} else {
+			positionsMap[validatorIndex].currentPeriod = append(positionsMap[validatorIndex].currentPeriod, types.CommitteeIndex(i))
+		}
+	}
+
+	nsc, err := st.NextSyncCommittee()
+	if err != nil {
+		return err
+	}
+	for i, pubkey := range nsc.Pubkeys {
+		p := bytesutil.ToBytes48(pubkey)
+		validatorIndex, ok := st.ValidatorIndexByPubkey(p)
+		if !ok {
+			continue
+		}
+		if _, ok := positionsMap[validatorIndex]; !ok {
+			m := &positionInCommittee{nextPeriod: []types.CommitteeIndex{types.CommitteeIndex(i)}, currentPeriod: []types.CommitteeIndex{}}
+			positionsMap[validatorIndex] = m
+		} else {
+			positionsMap[validatorIndex].nextPeriod = append(positionsMap[validatorIndex].nextPeriod, types.CommitteeIndex(i))
+		}
+	}
+
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	if err := s.cache.Add(&syncCommitteeIndexPosition{
+		currentSyncCommitteeRoot: syncCommitteeBoundaryRoot,
+		vIndexToPositionMap:      positionsMap,
+	}); err != nil {
+		return err
+	}
+	trim(s.cache, maxSyncCommitteeSize)
+
+	return nil
+}
+
+// Given the `syncCommitteeIndexPosition` object, this returns the key of the object.
+// The key is the `currentSyncCommitteeRoot` within the field.
+// Error gets returned if input does not comply with `currentSyncCommitteeRoot` object.
+func keyFn(obj interface{}) (string, error) {
+	info, ok := obj.(*syncCommitteeIndexPosition)
+	if !ok {
+		return "", errNotSyncCommitteeIndexPosition
+	}
+
+	return string(info.currentSyncCommitteeRoot[:]), nil
+}

beacon-chain/cache/sync_committee_disabled.go

@@ -0,0 +1,32 @@
+// +build libfuzzer
+
+package cache
+
+import (
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+)
+
+// FakeSyncCommitteeCache is a fake `SyncCommitteeCache` to satisfy fuzzing.
+type FakeSyncCommitteeCache struct {
+}
+
+// NewSyncCommittee initializes and returns a new SyncCommitteeCache.
+func NewSyncCommittee() *FakeSyncCommitteeCache {
+	return &FakeSyncCommitteeCache{}
+}
+
+// CurrentEpochIndexPosition -- fake.
+func (s *FakeSyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+	return nil, nil
+}
+
+// NextEpochIndexPosition -- fake.
+func (s *FakeSyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+	return nil, nil
+}
+
+// UpdatePositionsInCommittee -- fake.
+func (s *FakeSyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoot [32]byte, state state.BeaconStateAltair) error {
+	return nil
+}

beacon-chain/cache/sync_committee_test.go

@@ -0,0 +1,222 @@
+package cache_test
+
+import (
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
+	numValidators := 101
+	deterministicState, _ := testutil.DeterministicGenesisStateAltair(t, uint64(numValidators))
+	pubKeys := make([][]byte, deterministicState.NumValidators())
+	for i, val := range deterministicState.Validators() {
+		pubKeys[i] = val.PublicKey
+	}
+	tests := []struct {
+		name                 string
+		currentSyncCommittee *ethpb.SyncCommittee
+		nextSyncCommittee    *ethpb.SyncCommittee
+		currentSyncMap       map[types.ValidatorIndex][]types.CommitteeIndex
+		nextSyncMap          map[types.ValidatorIndex][]types.CommitteeIndex
+	}{
+		{
+			name: "only current epoch",
+			currentSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[1], pubKeys[2], pubKeys[3], pubKeys[2], pubKeys[2],
+			}),
+			nextSyncCommittee: convertToCommittee([][]byte{}),
+			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {0},
+				2: {1, 3, 4},
+				3: {2},
+			},
+			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {},
+				2: {},
+				3: {},
+			},
+		},
+		{
+			name:                 "only next epoch",
+			currentSyncCommittee: convertToCommittee([][]byte{}),
+			nextSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[1], pubKeys[2], pubKeys[3], pubKeys[2], pubKeys[2],
+			}),
+			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {},
+				2: {},
+				3: {},
+			},
+			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {0},
+				2: {1, 3, 4},
+				3: {2},
+			},
+		},
+		{
+			name: "some current epoch and some next epoch",
+			currentSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[1],
+				pubKeys[2],
+				pubKeys[3],
+				pubKeys[2],
+				pubKeys[2],
+			}),
+			nextSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[7],
+				pubKeys[6],
+				pubKeys[5],
+				pubKeys[4],
+				pubKeys[7],
+			}),
+			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {0},
+				2: {1, 3, 4},
+				3: {2},
+			},
+			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				7: {0, 4},
+				6: {1},
+				5: {2},
+				4: {3},
+			},
+		},
+		{
+			name: "some current epoch and some next epoch duplicated across",
+			currentSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[1],
+				pubKeys[2],
+				pubKeys[3],
+				pubKeys[2],
+				pubKeys[2],
+			}),
+			nextSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[2],
+				pubKeys[1],
+				pubKeys[3],
+				pubKeys[2],
+				pubKeys[1],
+			}),
+			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {0},
+				2: {1, 3, 4},
+				3: {2},
+			},
+			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {1, 4},
+				2: {0, 3},
+				3: {2},
+			},
+		},
+		{
+			name: "all duplicated",
+			currentSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+			}),
+			nextSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+			}),
+			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				100: {0, 1, 2, 3},
+			},
+			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				100: {0, 1, 2, 3},
+			},
+		},
+		{
+			name: "unknown keys",
+			currentSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+			}),
+			nextSyncCommittee: convertToCommittee([][]byte{
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+				pubKeys[100],
+			}),
+			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {},
+			},
+			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+				1: {},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s, _ := testutil.DeterministicGenesisStateAltair(t, uint64(numValidators))
+			require.NoError(t, s.SetCurrentSyncCommittee(tt.currentSyncCommittee))
+			require.NoError(t, s.SetNextSyncCommittee(tt.nextSyncCommittee))
+			cache := cache.NewSyncCommittee()
+			r := [32]byte{'a'}
+			require.NoError(t, cache.UpdatePositionsInCommittee(r, s))
+			for key, indices := range tt.currentSyncMap {
+				pos, err := cache.CurrentPeriodIndexPosition(r, key)
+				require.NoError(t, err)
+				require.DeepEqual(t, indices, pos)
+			}
+			for key, indices := range tt.nextSyncMap {
+				pos, err := cache.NextPeriodIndexPosition(r, key)
+				require.NoError(t, err)
+				require.DeepEqual(t, indices, pos)
+			}
+		})
+	}
+}
+
+func TestSyncCommitteeCache_RootDoesNotExist(t *testing.T) {
+	c := cache.NewSyncCommittee()
+	_, err := c.CurrentPeriodIndexPosition([32]byte{}, 0)
+	require.Equal(t, cache.ErrNonExistingSyncCommitteeKey, err)
+}
+
+func TestSyncCommitteeCache_CanRotate(t *testing.T) {
+	c := cache.NewSyncCommittee()
+	s, _ := testutil.DeterministicGenesisStateAltair(t, 64)
+	require.NoError(t, s.SetCurrentSyncCommittee(convertToCommittee([][]byte{{1}})))
+	require.NoError(t, c.UpdatePositionsInCommittee([32]byte{'a'}, s))
+	require.NoError(t, s.SetCurrentSyncCommittee(convertToCommittee([][]byte{{2}})))
+	require.NoError(t, c.UpdatePositionsInCommittee([32]byte{'b'}, s))
+	require.NoError(t, s.SetCurrentSyncCommittee(convertToCommittee([][]byte{{3}})))
+	require.NoError(t, c.UpdatePositionsInCommittee([32]byte{'c'}, s))
+	require.NoError(t, s.SetCurrentSyncCommittee(convertToCommittee([][]byte{{4}})))
+	require.NoError(t, c.UpdatePositionsInCommittee([32]byte{'d'}, s))
+
+	_, err := c.CurrentPeriodIndexPosition([32]byte{'a'}, 0)
+	require.Equal(t, cache.ErrNonExistingSyncCommitteeKey, err)
+
+	_, err = c.CurrentPeriodIndexPosition([32]byte{'c'}, 0)
+	require.NoError(t, err)
+}
+
+func convertToCommittee(inputKeys [][]byte) *ethpb.SyncCommittee {
+	var pubKeys [][]byte
+	for i := uint64(0); i < params.BeaconConfig().SyncCommitteeSize; i++ {
+		if i < uint64(len(inputKeys)) {
+			pubKeys = append(pubKeys, bytesutil.PadTo(inputKeys[i], params.BeaconConfig().BLSPubkeyLength))
+		} else {
+			pubKeys = append(pubKeys, bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength))
+		}
+	}
+
+	return &ethpb.SyncCommittee{
+		Pubkeys:         pubKeys,
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+}

beacon-chain/cache/sync_subnet_ids.go

@@ -0,0 +1,120 @@
+package cache
+
+import (
+	"sync"
+	"time"
+
+	"github.com/patrickmn/go-cache"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/rand"
+	"github.com/prysmaticlabs/prysm/shared/sliceutil"
+)
+
+type syncSubnetIDs struct {
+	sCommittee    *cache.Cache
+	sCommiteeLock sync.RWMutex
+}
+
+// SyncSubnetIDs for sync committee participant.
+var SyncSubnetIDs = newSyncSubnetIDs()
+
+func newSyncSubnetIDs() *syncSubnetIDs {
+	epochDuration := time.Duration(params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().SecondsPerSlot))
+	subLength := epochDuration * time.Duration(params.BeaconConfig().EpochsPerSyncCommitteePeriod)
+	persistentCache := cache.New(subLength*time.Second, epochDuration*time.Second)
+	return &syncSubnetIDs{sCommittee: persistentCache}
+}
+
+// GetSyncCommitteeSubnets retrieves the sync committee subnet and expiration time of that validator's
+// subscription.
+func (s *syncSubnetIDs) GetSyncCommitteeSubnets(pubkey []byte, epoch types.Epoch) ([]uint64, types.Epoch, bool, time.Time) {
+	s.sCommiteeLock.RLock()
+	defer s.sCommiteeLock.RUnlock()
+
+	id, duration, ok := s.sCommittee.GetWithExpiration(keyBuilder(pubkey, epoch))
+	if !ok {
+		return []uint64{}, 0, ok, time.Time{}
+	}
+	// Retrieve the slot from the cache.
+	idxs, ok := id.([]uint64)
+	if !ok {
+		return []uint64{}, 0, ok, time.Time{}
+	}
+	// If no committees are saved, we return
+	// nothing.
+	if len(idxs) <= 1 {
+		return []uint64{}, 0, ok, time.Time{}
+	}
+	return idxs[1:], types.Epoch(idxs[0]), ok, duration
+}
+
+// GetAllSubnets retrieves all the non-expired subscribed subnets of all the validators
+// in the cache. This method also takes the epoch as an argument to only retrieve
+// assingments for epochs that have happened.
+func (s *syncSubnetIDs) GetAllSubnets(currEpoch types.Epoch) []uint64 {
+	s.sCommiteeLock.RLock()
+	defer s.sCommiteeLock.RUnlock()
+
+	itemsMap := s.sCommittee.Items()
+	var committees []uint64
+
+	for _, v := range itemsMap {
+		if v.Expired() {
+			continue
+		}
+		idxs, ok := v.Object.([]uint64)
+		if !ok {
+			continue
+		}
+		if len(idxs) <= 1 {
+			continue
+		}
+		// Check if the subnet is valid in the current epoch.
+		if types.Epoch(idxs[0]) > currEpoch {
+			continue
+		}
+		// Ignore the first index as that represents the
+		// epoch of the validator's assignments.
+		committees = append(committees, idxs[1:]...)
+	}
+	return sliceutil.SetUint64(committees)
+}
+
+// AddSyncCommitteeSubnets adds the relevant committee for that particular validator along with its
+// expiration period. An Epoch argument here denotes the epoch from which the sync committee subnets
+// will be active.
+func (s *syncSubnetIDs) AddSyncCommitteeSubnets(pubkey []byte, epoch types.Epoch, comIndex []uint64, duration time.Duration) {
+	s.sCommiteeLock.Lock()
+	defer s.sCommiteeLock.Unlock()
+	subComCount := params.BeaconConfig().SyncCommitteeSubnetCount
+	// To join a sync committee subnet, select a random number of epochs before the end of the
+	// current sync committee period between 1 and SYNC_COMMITTEE_SUBNET_COUNT, inclusive.
+	diff := (rand.NewGenerator().Uint64() % subComCount) + 1
+	joinEpoch, err := epoch.SafeSub(diff)
+	if err != nil {
+		// If we overflow here, we simply set the value to join
+		// at 0.
+		joinEpoch = 0
+	}
+	// Append the epoch of the subnet into the first index here.
+	s.sCommittee.Set(keyBuilder(pubkey, epoch), append([]uint64{uint64(joinEpoch)}, comIndex...), duration)
+}
+
+// EmptyAllCaches empties out all the related caches and flushes any stored
+// entries on them. This should only ever be used for testing, in normal
+// production, handling of the relevant subnets for each role is done
+// separately.
+func (s *syncSubnetIDs) EmptyAllCaches() {
+	// Clear the cache.
+
+	s.sCommiteeLock.Lock()
+	s.sCommittee.Flush()
+	s.sCommiteeLock.Unlock()
+}
+
+func keyBuilder(pubkey []byte, epoch types.Epoch) string {
+	epochBytes := bytesutil.Bytes8(uint64(epoch))
+	return string(append(pubkey, epochBytes...))
+}

beacon-chain/cache/sync_subnet_ids_test.go

@@ -0,0 +1,57 @@
+package cache
+
+import (
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestSyncSubnetIDsCache_Roundtrip(t *testing.T) {
+	c := newSyncSubnetIDs()
+
+	for i := 0; i < 20; i++ {
+		pubkey := [48]byte{byte(i)}
+		c.AddSyncCommitteeSubnets(pubkey[:], 100, []uint64{uint64(i)}, 0)
+	}
+
+	for i := uint64(0); i < 20; i++ {
+		pubkey := [48]byte{byte(i)}
+
+		idxs, _, ok, _ := c.GetSyncCommitteeSubnets(pubkey[:], 100)
+		if !ok {
+			t.Errorf("Couldn't find entry in cache for pubkey %#x", pubkey)
+			continue
+		}
+		require.Equal(t, i, idxs[0])
+	}
+	coms := c.GetAllSubnets(100)
+	assert.Equal(t, 20, len(coms))
+}
+
+func TestSyncSubnetIDsCache_ValidateCurrentEpoch(t *testing.T) {
+	c := newSyncSubnetIDs()
+
+	for i := 0; i < 20; i++ {
+		pubkey := [48]byte{byte(i)}
+		c.AddSyncCommitteeSubnets(pubkey[:], 100, []uint64{uint64(i)}, 0)
+	}
+
+	coms := c.GetAllSubnets(50)
+	assert.Equal(t, 0, len(coms))
+
+	for i := uint64(0); i < 20; i++ {
+		pubkey := [48]byte{byte(i)}
+
+		_, jEpoch, ok, _ := c.GetSyncCommitteeSubnets(pubkey[:], 100)
+		if !ok {
+			t.Errorf("Couldn't find entry in cache for pubkey %#x", pubkey)
+			continue
+		}
+		require.Equal(t, true, uint64(jEpoch) >= 100-params.BeaconConfig().SyncCommitteeSubnetCount)
+	}
+
+	coms = c.GetAllSubnets(99)
+	assert.Equal(t, 20, len(coms))
+}

beacon-chain/core/altair/BUILD.bazel

@@ -3,19 +3,36 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
+        "attestation.go",
+        "block.go",
         "deposit.go",
+        "epoch_precompute.go",
+        "epoch_spec.go",
+        "fork_transition.go",
+        "reward.go",
         "sync_committee.go",
+        "transition.go",
+        "validator.go",
     ],
     importpath = "github.com/prysmaticlabs/prysm/beacon-chain/core/altair",
     visibility = [
         "//beacon-chain:__subpackages__",
         "//shared/testutil:__pkg__",
+        "//spectest:__subpackages__",
+        "//validator/client:__pkg__",
     ],
     deps = [
         "//beacon-chain/core/blocks:go_default_library",
+        "//beacon-chain/core/epoch:go_default_library",
+        "//beacon-chain/core/epoch/precompute:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/core/validators:go_default_library",
+        "//beacon-chain/p2p/types:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//proto/prysm/v1alpha1/block:go_default_library",
+        "//shared/attestationutil:go_default_library",
         "//shared/bls:go_default_library",
         "//shared/bytesutil:go_default_library",
         "//shared/hashutil:go_default_library",
@@ -23,28 +40,46 @@ go_library(
         "//shared/params:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",
+        "@io_opencensus_go//trace:go_default_library",
     ],
 )
 
 go_test(
     name = "go_default_test",
     srcs = [
+        "attestation_test.go",
+        "block_test.go",
         "deposit_fuzz_test.go",
         "deposit_test.go",
+        "epoch_precompute_test.go",
+        "epoch_spec_test.go",
+        "fork_transition_test.go",
+        "reward_test.go",
         "sync_committee_test.go",
+        "transition_test.go",
+        "validator_test.go",
     ],
+    embed = [":go_default_library"],
     deps = [
-        ":go_default_library",
+        "//beacon-chain/core/epoch/precompute:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/p2p/types:go_default_library",
+        "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//proto/prysm/v1alpha1/wrapper:go_default_library",
+        "//shared/attestationutil:go_default_library",
         "//shared/bls:go_default_library",
         "//shared/bytesutil:go_default_library",
         "//shared/params:go_default_library",
         "//shared/testutil:go_default_library",
+        "//shared/testutil/assert:go_default_library",
         "//shared/testutil/require:go_default_library",
+        "//shared/timeutils:go_default_library",
         "//shared/trieutil:go_default_library",
         "@com_github_google_gofuzz//:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",
+        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
     ],
 )

beacon-chain/core/altair/attestation.go

@@ -0,0 +1,284 @@
+package altair
+
+import (
+	"bytes"
+	"context"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/mathutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"go.opencensus.io/trace"
+)
+
+type matchingTarget bool
+type matchingSource bool
+type matchingHead bool
+
+// ProcessAttestations applies processing operations to a block's inner attestation
+// records.
+func ProcessAttestations(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	b block.SignedBeaconBlock,
+) (state.BeaconState, error) {
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
+		return nil, err
+	}
+
+	var err error
+	for idx, attestation := range b.Block().Body().Attestations() {
+		beaconState, err = ProcessAttestation(ctx, beaconState, attestation)
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not verify attestation at index %d in block", idx)
+		}
+	}
+	return beaconState, nil
+}
+
+// ProcessAttestation verifies an input attestation can pass through processing using the given beacon state.
+//
+// Spec code:
+//  def process_attestation(state: BeaconState, attestation: Attestation) -> None:
+//    data = attestation.data
+//    assert data.target.epoch in (get_previous_epoch(state), get_current_epoch(state))
+//    assert data.target.epoch == compute_epoch_at_slot(data.slot)
+//    assert data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot <= data.slot + SLOTS_PER_EPOCH
+//    assert data.index < get_committee_count_per_slot(state, data.target.epoch)
+//
+//    committee = get_beacon_committee(state, data.slot, data.index)
+//    assert len(attestation.aggregation_bits) == len(committee)
+//
+//    # Participation flag indices
+//    participation_flag_indices = get_attestation_participation_flag_indices(state, data, state.slot - data.slot)
+//
+//    # Verify signature
+//    assert is_valid_indexed_attestation(state, get_indexed_attestation(state, attestation))
+//
+//    # Update epoch participation flags
+//    if data.target.epoch == get_current_epoch(state):
+//        epoch_participation = state.current_epoch_participation
+//    else:
+//        epoch_participation = state.previous_epoch_participation
+//
+//    proposer_reward_numerator = 0
+//    for index in get_attesting_indices(state, data, attestation.aggregation_bits):
+//        for flag_index, weight in enumerate(PARTICIPATION_FLAG_WEIGHTS):
+//            if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
+//                epoch_participation[index] = add_flag(epoch_participation[index], flag_index)
+//                proposer_reward_numerator += get_base_reward(state, index) * weight
+//
+//    # Reward proposer
+//    proposer_reward_denominator = (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT) * WEIGHT_DENOMINATOR // PROPOSER_WEIGHT
+//    proposer_reward = Gwei(proposer_reward_numerator // proposer_reward_denominator)
+//    increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
+func ProcessAttestation(
+	ctx context.Context,
+	beaconState state.BeaconStateAltair,
+	att *ethpb.Attestation,
+) (state.BeaconStateAltair, error) {
+	beaconState, err := ProcessAttestationNoVerifySignature(ctx, beaconState, att)
+	if err != nil {
+		return nil, err
+	}
+	return beaconState, blocks.VerifyAttestationSignature(ctx, beaconState, att)
+}
+
+// ProcessAttestationsNoVerifySignature applies processing operations to a block's inner attestation
+// records. The only difference would be that the attestation signature would not be verified.
+func ProcessAttestationsNoVerifySignature(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	b block.SignedBeaconBlock,
+) (state.BeaconState, error) {
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
+		return nil, err
+	}
+	body := b.Block().Body()
+	var err error
+	for idx, attestation := range body.Attestations() {
+		beaconState, err = ProcessAttestationNoVerifySignature(ctx, beaconState, attestation)
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not verify attestation at index %d in block", idx)
+		}
+	}
+	return beaconState, nil
+}
+
+// ProcessAttestationNoVerifySignature processes the attestation without verifying the attestation signature. This
+// method is used to validate attestations whose signatures have already been verified or will be verified later.
+func ProcessAttestationNoVerifySignature(
+	ctx context.Context,
+	beaconState state.BeaconStateAltair,
+	att *ethpb.Attestation,
+) (state.BeaconStateAltair, error) {
+	ctx, span := trace.StartSpan(ctx, "altair.ProcessAttestationNoVerifySignature")
+	defer span.End()
+
+	if err := blocks.VerifyAttestationNoVerifySignature(ctx, beaconState, att); err != nil {
+		return nil, err
+	}
+
+	delay, err := beaconState.Slot().SafeSubSlot(att.Data.Slot)
+	if err != nil {
+		return nil, err
+	}
+	participatedFlags, err := attestationParticipationFlagIndices(
+		beaconState,
+		att.Data,
+		delay)
+	if err != nil {
+		return nil, err
+	}
+
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
+	if err != nil {
+		return nil, err
+	}
+	indices, err := attestationutil.AttestingIndices(att.AggregationBits, committee)
+	if err != nil {
+		return nil, err
+	}
+
+	var epochParticipation []byte
+	currentEpoch := helpers.CurrentEpoch(beaconState)
+	targetEpoch := att.Data.Target.Epoch
+	if targetEpoch == currentEpoch {
+		epochParticipation, err = beaconState.CurrentEpochParticipation()
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		epochParticipation, err = beaconState.PreviousEpochParticipation()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	sourceFlagIndex := params.BeaconConfig().TimelySourceFlagIndex
+	targetFlagIndex := params.BeaconConfig().TimelyTargetFlagIndex
+	headFlagIndex := params.BeaconConfig().TimelyHeadFlagIndex
+	proposerRewardNumerator := uint64(0)
+	totalBalance, err := helpers.TotalActiveBalance(beaconState)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not calculate active balance")
+	}
+	for _, index := range indices {
+		br, err := BaseRewardWithTotalBalance(beaconState, types.ValidatorIndex(index), totalBalance)
+		if err != nil {
+			return nil, err
+		}
+		if participatedFlags[sourceFlagIndex] && !HasValidatorFlag(epochParticipation[index], sourceFlagIndex) {
+			epochParticipation[index] = AddValidatorFlag(epochParticipation[index], sourceFlagIndex)
+			proposerRewardNumerator += br * params.BeaconConfig().TimelySourceWeight
+		}
+		if participatedFlags[targetFlagIndex] && !HasValidatorFlag(epochParticipation[index], targetFlagIndex) {
+			epochParticipation[index] = AddValidatorFlag(epochParticipation[index], targetFlagIndex)
+			proposerRewardNumerator += br * params.BeaconConfig().TimelyTargetWeight
+		}
+		if participatedFlags[headFlagIndex] && !HasValidatorFlag(epochParticipation[index], headFlagIndex) {
+			epochParticipation[index] = AddValidatorFlag(epochParticipation[index], headFlagIndex)
+			proposerRewardNumerator += br * params.BeaconConfig().TimelyHeadWeight
+		}
+	}
+
+	if targetEpoch == currentEpoch {
+		if err := beaconState.SetCurrentParticipationBits(epochParticipation); err != nil {
+			return nil, err
+		}
+	} else {
+		if err := beaconState.SetPreviousParticipationBits(epochParticipation); err != nil {
+			return nil, err
+		}
+	}
+
+	// Reward proposer.
+	if err := rewardProposer(beaconState, proposerRewardNumerator); err != nil {
+		return nil, err
+	}
+	return beaconState, nil
+}
+
+// This returns the matching statues for attestation data's source target and head.
+func matchingStatus(beaconState state.BeaconState, data *ethpb.AttestationData, cp *ethpb.Checkpoint) (s matchingSource, t matchingTarget, h matchingHead, err error) {
+	s = matchingSource(attestationutil.CheckPointIsEqual(data.Source, cp))
+
+	r, err := helpers.BlockRoot(beaconState, data.Target.Epoch)
+	if err != nil {
+		return false, false, false, err
+	}
+	t = matchingTarget(bytes.Equal(r, data.Target.Root))
+
+	r, err = helpers.BlockRootAtSlot(beaconState, data.Slot)
+	if err != nil {
+		return false, false, false, err
+	}
+	h = matchingHead(bytes.Equal(r, data.BeaconBlockRoot))
+	return
+}
+
+// This rewards proposer by increasing proposer's balance with input reward numerator and calculated reward denominator.
+func rewardProposer(beaconState state.BeaconState, proposerRewardNumerator uint64) error {
+	proposerRewardDenominator := (params.BeaconConfig().WeightDenominator - params.BeaconConfig().ProposerWeight) * params.BeaconConfig().WeightDenominator / params.BeaconConfig().ProposerWeight
+	proposerReward := proposerRewardNumerator / proposerRewardDenominator
+	i, err := helpers.BeaconProposerIndex(beaconState)
+	if err != nil {
+		return err
+	}
+
+	return helpers.IncreaseBalance(beaconState, i, proposerReward)
+}
+
+// HasValidatorFlag returns true if the flag at position has set.
+func HasValidatorFlag(flag, flagPosition uint8) bool {
+	return ((flag >> flagPosition) & 1) == 1
+}
+
+// AddValidatorFlag adds new validator flag to existing one.
+func AddValidatorFlag(flag, flagPosition uint8) uint8 {
+	return flag | (1 << flagPosition)
+}
+
+// This retrieves a map of attestation scoring based on Altair's participation flag indices.
+// This is used to facilitate process attestation during state transition.
+func attestationParticipationFlagIndices(beaconState state.BeaconStateAltair, data *ethpb.AttestationData, delay types.Slot) (map[uint8]bool, error) {
+	currEpoch := helpers.CurrentEpoch(beaconState)
+	var justifiedCheckpt *ethpb.Checkpoint
+	if data.Target.Epoch == currEpoch {
+		justifiedCheckpt = beaconState.CurrentJustifiedCheckpoint()
+	} else {
+		justifiedCheckpt = beaconState.PreviousJustifiedCheckpoint()
+	}
+
+	// Get matching participation flags.
+	matchingSource, matchingTarget, matchingHead, err := matchingStatus(beaconState, data, justifiedCheckpt)
+	if err != nil {
+		return nil, err
+	}
+	if !matchingSource {
+		return nil, errors.New("source epoch does not match")
+	}
+
+	// Process matched participation flags.
+	participatedFlags := make(map[uint8]bool)
+	sourceFlagIndex := params.BeaconConfig().TimelySourceFlagIndex
+	targetFlagIndex := params.BeaconConfig().TimelyTargetFlagIndex
+	headFlagIndex := params.BeaconConfig().TimelyHeadFlagIndex
+	if matchingSource && delay <= types.Slot(mathutil.IntegerSquareRoot(uint64(params.BeaconConfig().SlotsPerEpoch))) {
+		participatedFlags[sourceFlagIndex] = true
+	}
+	if matchingTarget && delay <= params.BeaconConfig().SlotsPerEpoch {
+		participatedFlags[targetFlagIndex] = true
+	}
+	matchingHeadTarget := bool(matchingHead) && bool(matchingTarget)
+	if matchingHeadTarget && delay == params.BeaconConfig().MinAttestationInclusionDelay {
+		participatedFlags[headFlagIndex] = true
+	}
+	return participatedFlags, nil
+}

beacon-chain/core/altair/attestation_test.go

@@ -0,0 +1,344 @@
+package altair_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	fuzz "github.com/google/gofuzz"
+	"github.com/prysmaticlabs/go-bitfield"
+	altair "github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestProcessAttestations_InclusionDelayFailure(t *testing.T) {
+	attestations := []*ethpb.Attestation{
+		testutil.HydrateAttestation(&ethpb.Attestation{
+			Data: &ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+				Slot:   5,
+			},
+		}),
+	}
+	b := testutil.NewBeaconBlockAltair()
+	b.Block = &ethpb.BeaconBlockAltair{
+		Body: &ethpb.BeaconBlockBodyAltair{
+			Attestations: attestations,
+		},
+	}
+	beaconState, _ := testutil.DeterministicGenesisStateAltair(t, 100)
+
+	want := fmt.Sprintf(
+		"attestation slot %d + inclusion delay %d > state slot %d",
+		attestations[0].Data.Slot,
+		params.BeaconConfig().MinAttestationInclusionDelay,
+		beaconState.Slot(),
+	)
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_NeitherCurrentNorPrevEpoch(t *testing.T) {
+	att := testutil.HydrateAttestation(&ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 0, Root: []byte("hello-world")},
+			Target: &ethpb.Checkpoint{Epoch: 0}}})
+
+	b := testutil.NewBeaconBlockAltair()
+	b.Block = &ethpb.BeaconBlockAltair{
+		Body: &ethpb.BeaconBlockBodyAltair{
+			Attestations: []*ethpb.Attestation{att},
+		},
+	}
+	beaconState, _ := testutil.DeterministicGenesisStateAltair(t, 100)
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().SlotsPerEpoch*4 + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+	pfc := beaconState.PreviousJustifiedCheckpoint()
+	pfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
+
+	want := fmt.Sprintf(
+		"expected target epoch (%d) to be the previous epoch (%d) or the current epoch (%d)",
+		att.Data.Target.Epoch,
+		helpers.PrevEpoch(beaconState),
+		helpers.CurrentEpoch(beaconState),
+	)
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_CurrentEpochFFGDataMismatches(t *testing.T) {
+	attestations := []*ethpb.Attestation{
+		{
+			Data: &ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+				Source: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+			},
+			AggregationBits: bitfield.Bitlist{0x09},
+		},
+	}
+	b := testutil.NewBeaconBlockAltair()
+	b.Block = &ethpb.BeaconBlockAltair{
+		Body: &ethpb.BeaconBlockBodyAltair{
+			Attestations: attestations,
+		},
+	}
+	beaconState, _ := testutil.DeterministicGenesisStateAltair(t, 100)
+	require.NoError(t, beaconState.SetSlot(beaconState.Slot()+params.BeaconConfig().MinAttestationInclusionDelay))
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+
+	want := "source check point not equal to current justified checkpoint"
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, want, err)
+	b.Block.Body.Attestations[0].Data.Source.Epoch = helpers.CurrentEpoch(beaconState)
+	b.Block.Body.Attestations[0].Data.Source.Root = []byte{}
+	wsb, err = wrapper.WrappedAltairSignedBeaconBlock(b)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_PrevEpochFFGDataMismatches(t *testing.T) {
+	beaconState, _ := testutil.DeterministicGenesisStateAltair(t, 100)
+
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(0, true)
+	attestations := []*ethpb.Attestation{
+		{
+			Data: &ethpb.AttestationData{
+				Source: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+				Target: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+				Slot:   params.BeaconConfig().SlotsPerEpoch,
+			},
+			AggregationBits: aggBits,
+		},
+	}
+	b := testutil.NewBeaconBlockAltair()
+	b.Block = &ethpb.BeaconBlockAltair{
+		Body: &ethpb.BeaconBlockBodyAltair{
+			Attestations: attestations,
+		},
+	}
+
+	err := beaconState.SetSlot(beaconState.Slot() + 2*params.BeaconConfig().SlotsPerEpoch)
+	require.NoError(t, err)
+	pfc := beaconState.PreviousJustifiedCheckpoint()
+	pfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
+
+	want := "source check point not equal to previous justified checkpoint"
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, want, err)
+	b.Block.Body.Attestations[0].Data.Source.Epoch = helpers.PrevEpoch(beaconState)
+	b.Block.Body.Attestations[0].Data.Target.Epoch = helpers.PrevEpoch(beaconState)
+	b.Block.Body.Attestations[0].Data.Source.Root = []byte{}
+	wsb, err = wrapper.WrappedAltairSignedBeaconBlock(b)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_InvalidAggregationBitsLength(t *testing.T) {
+	beaconState, _ := testutil.DeterministicGenesisStateAltair(t, 100)
+
+	aggBits := bitfield.NewBitlist(4)
+	att := &ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 0, Root: []byte("hello-world")},
+			Target: &ethpb.Checkpoint{Epoch: 0}},
+		AggregationBits: aggBits,
+	}
+
+	b := testutil.NewBeaconBlockAltair()
+	b.Block = &ethpb.BeaconBlockAltair{
+		Body: &ethpb.BeaconBlockBodyAltair{
+			Attestations: []*ethpb.Attestation{att},
+		},
+	}
+
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+
+	expected := "failed to verify aggregation bitfield: wanted participants bitfield length 3, got: 4"
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, expected, err)
+}
+
+func TestProcessAttestations_OK(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisStateAltair(t, 100)
+
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(0, true)
+	var mockRoot [32]byte
+	copy(mockRoot[:], "hello-world")
+	att := testutil.HydrateAttestation(&ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Root: mockRoot[:]},
+			Target: &ethpb.Checkpoint{Root: mockRoot[:]},
+		},
+		AggregationBits: aggBits,
+	})
+
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = mockRoot[:]
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
+	require.NoError(t, err)
+	attestingIndices, err := attestationutil.AttestingIndices(att.AggregationBits, committee)
+	require.NoError(t, err)
+	sigs := make([]bls.Signature, len(attestingIndices))
+	for i, indice := range attestingIndices {
+		sb, err := helpers.ComputeDomainAndSign(beaconState, 0, att.Data, params.BeaconConfig().DomainBeaconAttester, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		sigs[i] = sig
+	}
+	att.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	block := testutil.NewBeaconBlockAltair()
+	block.Block.Body.Attestations = []*ethpb.Attestation{att}
+
+	err = beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	_, err = altair.ProcessAttestations(context.Background(), beaconState, wsb)
+	require.NoError(t, err)
+}
+
+func TestProcessAttestationNoVerify_SourceTargetHead(t *testing.T) {
+	beaconState, _ := testutil.DeterministicGenesisStateAltair(t, 64)
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+
+	aggBits := bitfield.NewBitlist(2)
+	aggBits.SetBitAt(0, true)
+	aggBits.SetBitAt(1, true)
+	r, err := helpers.BlockRootAtSlot(beaconState, 0)
+	require.NoError(t, err)
+	att := &ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			BeaconBlockRoot: r,
+			Source:          &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+			Target:          &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+		},
+		AggregationBits: aggBits,
+	}
+	zeroSig := [96]byte{}
+	att.Signature = zeroSig[:]
+
+	ckp := beaconState.CurrentJustifiedCheckpoint()
+	copy(ckp.Root, make([]byte, 32))
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
+
+	beaconState, err = altair.ProcessAttestationNoVerifySignature(context.Background(), beaconState, att)
+	require.NoError(t, err)
+
+	p, err := beaconState.CurrentEpochParticipation()
+	require.NoError(t, err)
+
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
+	require.NoError(t, err)
+	indices, err := attestationutil.AttestingIndices(att.AggregationBits, committee)
+	require.NoError(t, err)
+	for _, index := range indices {
+		require.Equal(t, true, altair.HasValidatorFlag(p[index], params.BeaconConfig().TimelyHeadFlagIndex))
+		require.Equal(t, true, altair.HasValidatorFlag(p[index], params.BeaconConfig().TimelyTargetFlagIndex))
+		require.Equal(t, true, altair.HasValidatorFlag(p[index], params.BeaconConfig().TimelySourceFlagIndex))
+	}
+}
+
+func TestValidatorFlag_AddHas(t *testing.T) {
+	tests := []struct {
+		name          string
+		set           []uint8
+		expectedTrue  []uint8
+		expectedFalse []uint8
+	}{
+		{name: "none",
+			set:           []uint8{},
+			expectedTrue:  []uint8{},
+			expectedFalse: []uint8{params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex, params.BeaconConfig().TimelyHeadFlagIndex},
+		},
+		{
+			name:          "source",
+			set:           []uint8{params.BeaconConfig().TimelySourceFlagIndex},
+			expectedTrue:  []uint8{params.BeaconConfig().TimelySourceFlagIndex},
+			expectedFalse: []uint8{params.BeaconConfig().TimelyTargetFlagIndex, params.BeaconConfig().TimelyHeadFlagIndex},
+		},
+		{
+			name:          "source, target",
+			set:           []uint8{params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex},
+			expectedTrue:  []uint8{params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex},
+			expectedFalse: []uint8{params.BeaconConfig().TimelyHeadFlagIndex},
+		},
+		{name: "source, target, head",
+			set:           []uint8{params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex, params.BeaconConfig().TimelyHeadFlagIndex},
+			expectedTrue:  []uint8{params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex, params.BeaconConfig().TimelyHeadFlagIndex},
+			expectedFalse: []uint8{},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			b := uint8(0)
+			for _, f := range tt.set {
+				b = altair.AddValidatorFlag(b, f)
+			}
+			for _, f := range tt.expectedFalse {
+				require.Equal(t, false, altair.HasValidatorFlag(b, f))
+			}
+			for _, f := range tt.expectedTrue {
+				require.Equal(t, true, altair.HasValidatorFlag(b, f))
+			}
+		})
+	}
+}
+
+func TestFuzzProcessAttestationsNoVerify_10000(t *testing.T) {
+	fuzzer := fuzz.NewWithSeed(0)
+	state := &ethpb.BeaconStateAltair{}
+	b := &ethpb.SignedBeaconBlockAltair{Block: &ethpb.BeaconBlockAltair{}}
+	ctx := context.Background()
+	for i := 0; i < 10000; i++ {
+		fuzzer.Fuzz(state)
+		fuzzer.Fuzz(b)
+		if b.Block == nil {
+			b.Block = &ethpb.BeaconBlockAltair{}
+		}
+		s, err := stateAltair.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		r, err := altair.ProcessAttestationsNoVerifySignature(ctx, s, wsb)
+		if err != nil && r != nil {
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, b)
+		}
+	}
+}

beacon-chain/core/altair/block.go

@@ -0,0 +1,130 @@
+package altair
+
+import (
+	"errors"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	p2pType "github.com/prysmaticlabs/prysm/beacon-chain/p2p/types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// ProcessSyncAggregate verifies sync committee aggregate signature signing over the previous slot block root.
+//
+// Spec code:
+// def process_sync_aggregate(state: BeaconState, sync_aggregate: SyncAggregate) -> None:
+//    # Verify sync committee aggregate signature signing over the previous slot block root
+//    committee_pubkeys = state.current_sync_committee.pubkeys
+//    participant_pubkeys = [pubkey for pubkey, bit in zip(committee_pubkeys, sync_aggregate.sync_committee_bits) if bit]
+//    previous_slot = max(state.slot, Slot(1)) - Slot(1)
+//    domain = get_domain(state, DOMAIN_SYNC_COMMITTEE, compute_epoch_at_slot(previous_slot))
+//    signing_root = compute_signing_root(get_block_root_at_slot(state, previous_slot), domain)
+//    assert eth2_fast_aggregate_verify(participant_pubkeys, signing_root, sync_aggregate.sync_committee_signature)
+//
+//    # Compute participant and proposer rewards
+//    total_active_increments = get_total_active_balance(state) // EFFECTIVE_BALANCE_INCREMENT
+//    total_base_rewards = Gwei(get_base_reward_per_increment(state) * total_active_increments)
+//    max_participant_rewards = Gwei(total_base_rewards * SYNC_REWARD_WEIGHT // WEIGHT_DENOMINATOR // SLOTS_PER_EPOCH)
+//    participant_reward = Gwei(max_participant_rewards // SYNC_COMMITTEE_SIZE)
+//    proposer_reward = Gwei(participant_reward * PROPOSER_WEIGHT // (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT))
+//
+//    # Apply participant and proposer rewards
+//    all_pubkeys = [v.pubkey for v in state.validators]
+//    committee_indices = [ValidatorIndex(all_pubkeys.index(pubkey)) for pubkey in state.current_sync_committee.pubkeys]
+//    for participant_index, participation_bit in zip(committee_indices, sync_aggregate.sync_committee_bits):
+//        if participation_bit:
+//            increase_balance(state, participant_index, participant_reward)
+//            increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
+//        else:
+//            decrease_balance(state, participant_index, participant_reward)
+func ProcessSyncAggregate(state state.BeaconStateAltair, sync *ethpb.SyncAggregate) (state.BeaconStateAltair, error) {
+	currentSyncCommittee, err := state.CurrentSyncCommittee()
+	if err != nil {
+		return nil, err
+	}
+	committeeKeys := currentSyncCommittee.Pubkeys
+	votedKeys := make([]bls.PublicKey, 0, len(committeeKeys))
+	votedIndices := make([]types.ValidatorIndex, 0, len(committeeKeys))
+	didntVoteIndices := make([]types.ValidatorIndex, 0, len(committeeKeys))
+	// Verify sync committee signature.
+	for i := uint64(0); i < sync.SyncCommitteeBits.Len(); i++ {
+		vIdx, exists := state.ValidatorIndexByPubkey(bytesutil.ToBytes48(committeeKeys[i]))
+		// Impossible scenario.
+		if !exists {
+			return nil, errors.New("validator public key does not exist in state")
+		}
+
+		if sync.SyncCommitteeBits.BitAt(i) {
+			pubKey, err := bls.PublicKeyFromBytes(committeeKeys[i])
+			if err != nil {
+				return nil, err
+			}
+			votedKeys = append(votedKeys, pubKey)
+			votedIndices = append(votedIndices, vIdx)
+		} else {
+			didntVoteIndices = append(didntVoteIndices, vIdx)
+		}
+	}
+	ps := helpers.PrevSlot(state.Slot())
+	d, err := helpers.Domain(state.Fork(), helpers.SlotToEpoch(ps), params.BeaconConfig().DomainSyncCommittee, state.GenesisValidatorRoot())
+	if err != nil {
+		return nil, err
+	}
+	pbr, err := helpers.BlockRootAtSlot(state, ps)
+	if err != nil {
+		return nil, err
+	}
+	sszBytes := p2pType.SSZBytes(pbr)
+	r, err := helpers.ComputeSigningRoot(&sszBytes, d)
+	if err != nil {
+		return nil, err
+	}
+	sig, err := bls.SignatureFromBytes(sync.SyncCommitteeSignature)
+	if err != nil {
+		return nil, err
+	}
+	if !sig.Eth2FastAggregateVerify(votedKeys, r) {
+		return nil, errors.New("could not verify sync committee signature")
+	}
+
+	// Calculate sync committee and proposer rewards
+	activeBalance, err := helpers.TotalActiveBalance(state)
+	if err != nil {
+		return nil, err
+	}
+	totalActiveIncrements := activeBalance / params.BeaconConfig().EffectiveBalanceIncrement
+	totalBaseRewards := baseRewardPerIncrement(activeBalance) * totalActiveIncrements
+	maxParticipantRewards := totalBaseRewards * params.BeaconConfig().SyncRewardWeight / params.BeaconConfig().WeightDenominator / uint64(params.BeaconConfig().SlotsPerEpoch)
+	participantReward := maxParticipantRewards / params.BeaconConfig().SyncCommitteeSize
+	proposerReward := participantReward * params.BeaconConfig().ProposerWeight / (params.BeaconConfig().WeightDenominator - params.BeaconConfig().ProposerWeight)
+
+	// Apply sync committee rewards.
+	earnedProposerReward := uint64(0)
+	for _, index := range votedIndices {
+		if err := helpers.IncreaseBalance(state, index, participantReward); err != nil {
+			return nil, err
+		}
+		earnedProposerReward += proposerReward
+	}
+	// Apply proposer rewards.
+	proposerIndex, err := helpers.BeaconProposerIndex(state)
+	if err != nil {
+		return nil, err
+	}
+	if err := helpers.IncreaseBalance(state, proposerIndex, earnedProposerReward); err != nil {
+		return nil, err
+	}
+
+	// Apply sync committee penalties.
+	for _, index := range didntVoteIndices {
+		if err := helpers.DecreaseBalance(state, index, participantReward); err != nil {
+			return nil, err
+		}
+	}
+
+	return state, nil
+}

beacon-chain/core/altair/block_test.go

@@ -0,0 +1,91 @@
+package altair_test
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	p2pType "github.com/prysmaticlabs/prysm/beacon-chain/p2p/types"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestProcessSyncCommittee_OK(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().MaxValidatorsPerCommittee)
+	require.NoError(t, beaconState.SetSlot(1))
+	committee, err := altair.NextSyncCommittee(context.Background(), beaconState)
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetCurrentSyncCommittee(committee))
+
+	syncBits := bitfield.NewBitvector512()
+	for i := range syncBits {
+		syncBits[i] = 0xff
+	}
+	indices, err := altair.NextSyncCommitteeIndices(context.Background(), beaconState)
+	require.NoError(t, err)
+	ps := helpers.PrevSlot(beaconState.Slot())
+	pbr, err := helpers.BlockRootAtSlot(beaconState, ps)
+	require.NoError(t, err)
+	sigs := make([]bls.Signature, len(indices))
+	for i, indice := range indices {
+		b := p2pType.SSZBytes(pbr)
+		sb, err := helpers.ComputeDomainAndSign(beaconState, helpers.CurrentEpoch(beaconState), &b, params.BeaconConfig().DomainSyncCommittee, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		sigs[i] = sig
+	}
+	aggregatedSig := bls.AggregateSignatures(sigs).Marshal()
+	syncAggregate := &ethpb.SyncAggregate{
+		SyncCommitteeBits:      syncBits,
+		SyncCommitteeSignature: aggregatedSig,
+	}
+
+	beaconState, err = altair.ProcessSyncAggregate(beaconState, syncAggregate)
+	require.NoError(t, err)
+
+	// Use a non-sync committee index to compare profitability.
+	syncCommittee := make(map[types.ValidatorIndex]bool)
+	for _, index := range indices {
+		syncCommittee[index] = true
+	}
+	nonSyncIndex := types.ValidatorIndex(params.BeaconConfig().MaxValidatorsPerCommittee + 1)
+	for i := types.ValidatorIndex(0); uint64(i) < params.BeaconConfig().MaxValidatorsPerCommittee; i++ {
+		if !syncCommittee[i] {
+			nonSyncIndex = i
+			break
+		}
+	}
+
+	// Sync committee should be more profitable than non sync committee
+	balances := beaconState.Balances()
+	require.Equal(t, true, balances[indices[0]] > balances[nonSyncIndex])
+
+	// Proposer should be more profitable than rest of the sync committee
+	proposerIndex, err := helpers.BeaconProposerIndex(beaconState)
+	require.NoError(t, err)
+	require.Equal(t, true, balances[proposerIndex] > balances[indices[0]])
+
+	// Sync committee should have the same profits, except you are a proposer
+	for i := 1; i < len(indices); i++ {
+		if proposerIndex == indices[i-1] || proposerIndex == indices[i] {
+			continue
+		}
+		require.Equal(t, balances[indices[i-1]], balances[indices[i]])
+	}
+
+	// Increased balance validator count should equal to sync committee count
+	increased := uint64(0)
+	for _, balance := range balances {
+		if balance > params.BeaconConfig().MaxEffectiveBalance {
+			increased++
+		}
+	}
+	require.Equal(t, params.BeaconConfig().SyncCommitteeSize, increased)
+}

beacon-chain/core/altair/deposit_fuzz_test.go

@@ -8,13 +8,12 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
 	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )
 
 func TestFuzzProcessDeposits_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &statepb.BeaconStateAltair{}
+	state := &ethpb.BeaconStateAltair{}
 	deposits := make([]*ethpb.Deposit, 100)
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
@@ -33,7 +32,7 @@ func TestFuzzProcessDeposits_10000(t *testing.T) {
 
 func TestFuzzProcessDeposit_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &statepb.BeaconStateAltair{}
+	state := &ethpb.BeaconStateAltair{}
 	deposit := &ethpb.Deposit{}
 
 	for i := 0; i < 10000; i++ {

beacon-chain/core/altair/epoch_precompute.go

@@ -0,0 +1,257 @@
+package altair
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/shared/mathutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"go.opencensus.io/trace"
+)
+
+// InitializeEpochValidators gets called at the beginning of process epoch cycle to return
+// pre computed instances of validators attesting records and total
+// balances attested in an epoch.
+func InitializeEpochValidators(ctx context.Context, st state.BeaconStateAltair) ([]*precompute.Validator, *precompute.Balance, error) {
+	ctx, span := trace.StartSpan(ctx, "altair.InitializeEpochValidators")
+	defer span.End()
+	pValidators := make([]*precompute.Validator, st.NumValidators())
+	bal := &precompute.Balance{}
+	prevEpoch := helpers.PrevEpoch(st)
+
+	inactivityScores, err := st.InactivityScores()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// This shouldn't happen with a correct beacon state,
+	// but rather be safe to defend against index out of bound panics.
+	if st.NumValidators() > len(inactivityScores) {
+		return nil, nil, errors.New("num of validators can't be greater than length of inactivity scores")
+	}
+	if err := st.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
+		// Was validator withdrawable or slashed
+		withdrawable := prevEpoch+1 >= val.WithdrawableEpoch()
+		pVal := &precompute.Validator{
+			IsSlashed:                    val.Slashed(),
+			IsWithdrawableCurrentEpoch:   withdrawable,
+			CurrentEpochEffectiveBalance: val.EffectiveBalance(),
+			InactivityScore:              inactivityScores[idx],
+		}
+		// Validator active current epoch
+		if helpers.IsActiveValidatorUsingTrie(val, helpers.CurrentEpoch(st)) {
+			pVal.IsActiveCurrentEpoch = true
+			bal.ActiveCurrentEpoch += val.EffectiveBalance()
+		}
+		// Validator active previous epoch
+		if helpers.IsActiveValidatorUsingTrie(val, prevEpoch) {
+			pVal.IsActivePrevEpoch = true
+			bal.ActivePrevEpoch += val.EffectiveBalance()
+		}
+
+		pValidators[idx] = pVal
+		return nil
+	}); err != nil {
+		return nil, nil, errors.Wrap(err, "could not initialize epoch validator")
+	}
+	return pValidators, bal, nil
+}
+
+// ProcessInactivityScores of beacon chain. This updates inactivity scores of beacon chain and
+// updates the precompute validator struct for later processing.
+func ProcessInactivityScores(
+	ctx context.Context,
+	state state.BeaconState,
+	vals []*precompute.Validator,
+) (state.BeaconState, []*precompute.Validator, error) {
+	if helpers.CurrentEpoch(state) == params.BeaconConfig().GenesisEpoch {
+		return state, vals, nil
+	}
+
+	inactivityScores, err := state.InactivityScores()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	for i, v := range vals {
+		if v.IsPrevEpochTargetAttester && !v.IsSlashed {
+			// Decrease inactivity score when validator gets target correct.
+			if v.InactivityScore > 0 {
+				score := uint64(1)
+				if score > v.InactivityScore {
+					score = v.InactivityScore
+				}
+				v.InactivityScore -= score
+			}
+		} else {
+			v.InactivityScore += params.BeaconConfig().InactivityScoreBias
+		}
+		if !helpers.IsInInactivityLeak(helpers.PrevEpoch(state), state.FinalizedCheckpointEpoch()) {
+			score := params.BeaconConfig().InactivityScoreRecoveryRate
+			if score > v.InactivityScore {
+				score = v.InactivityScore
+			}
+			v.InactivityScore -= score
+
+		}
+		inactivityScores[i] = v.InactivityScore
+	}
+
+	if err := state.SetInactivityScores(inactivityScores); err != nil {
+		return nil, nil, err
+	}
+
+	return state, vals, nil
+}
+
+// ProcessEpochParticipation processes the epoch participation in state and updates individual validator's pre computes,
+// it also tracks and updates epoch attesting balances.
+func ProcessEpochParticipation(
+	ctx context.Context,
+	state state.BeaconState,
+	bal *precompute.Balance,
+	vals []*precompute.Validator,
+) ([]*precompute.Validator, *precompute.Balance, error) {
+	ctx, span := trace.StartSpan(ctx, "altair.ProcessEpochParticipation")
+	defer span.End()
+
+	cp, err := state.CurrentEpochParticipation()
+	if err != nil {
+		return nil, nil, err
+	}
+	for i, b := range cp {
+		if HasValidatorFlag(b, params.BeaconConfig().TimelyTargetFlagIndex) {
+			vals[i].IsCurrentEpochTargetAttester = true
+		}
+	}
+	pp, err := state.PreviousEpochParticipation()
+	if err != nil {
+		return nil, nil, err
+	}
+	for i, b := range pp {
+		if HasValidatorFlag(b, params.BeaconConfig().TimelySourceFlagIndex) {
+			vals[i].IsPrevEpochAttester = true
+		}
+		if HasValidatorFlag(b, params.BeaconConfig().TimelyTargetFlagIndex) {
+			vals[i].IsPrevEpochTargetAttester = true
+		}
+		if HasValidatorFlag(b, params.BeaconConfig().TimelyHeadFlagIndex) {
+			vals[i].IsPrevEpochHeadAttester = true
+		}
+	}
+	bal = precompute.UpdateBalance(vals, bal)
+	return vals, bal, nil
+}
+
+// ProcessRewardsAndPenaltiesPrecompute processes the rewards and penalties of individual validator.
+// This is an optimized version by passing in precomputed validator attesting records and and total epoch balances.
+func ProcessRewardsAndPenaltiesPrecompute(
+	state state.BeaconStateAltair,
+	bal *precompute.Balance,
+	vals []*precompute.Validator,
+) (state.BeaconStateAltair, error) {
+	// Don't process rewards and penalties in genesis epoch.
+	if helpers.CurrentEpoch(state) == 0 {
+		return state, nil
+	}
+
+	numOfVals := state.NumValidators()
+	// Guard against an out-of-bounds using validator balance precompute.
+	if len(vals) != numOfVals || len(vals) != state.BalancesLength() {
+		return state, errors.New("validator registries not the same length as state's validator registries")
+	}
+
+	attsRewards, attsPenalties, err := AttestationsDelta(state, bal, vals)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get attestation delta")
+	}
+
+	balances := state.Balances()
+	for i := 0; i < numOfVals; i++ {
+		vals[i].BeforeEpochTransitionBalance = balances[i]
+
+		// Compute the post balance of the validator after accounting for the
+		// attester and proposer rewards and penalties.
+		balances[i] = helpers.IncreaseBalanceWithVal(balances[i], attsRewards[i])
+		balances[i] = helpers.DecreaseBalanceWithVal(balances[i], attsPenalties[i])
+
+		vals[i].AfterEpochTransitionBalance = balances[i]
+	}
+
+	if err := state.SetBalances(balances); err != nil {
+		return nil, errors.Wrap(err, "could not set validator balances")
+	}
+
+	return state, nil
+}
+
+// AttestationsDelta computes and returns the rewards and penalties differences for individual validators based on the
+// voting records.
+func AttestationsDelta(state state.BeaconStateAltair, bal *precompute.Balance, vals []*precompute.Validator) (rewards, penalties []uint64, err error) {
+	numOfVals := state.NumValidators()
+	rewards = make([]uint64, numOfVals)
+	penalties = make([]uint64, numOfVals)
+	prevEpoch := helpers.PrevEpoch(state)
+	finalizedEpoch := state.FinalizedCheckpointEpoch()
+
+	for i, v := range vals {
+		rewards[i], penalties[i] = attestationDelta(bal, v, prevEpoch, finalizedEpoch)
+	}
+
+	return rewards, penalties, nil
+}
+
+func attestationDelta(bal *precompute.Balance, v *precompute.Validator, prevEpoch, finalizedEpoch types.Epoch) (r, p uint64) {
+	eligible := v.IsActivePrevEpoch || (v.IsSlashed && !v.IsWithdrawableCurrentEpoch)
+	if !eligible || bal.ActiveCurrentEpoch == 0 {
+		return 0, 0
+	}
+
+	ebi := params.BeaconConfig().EffectiveBalanceIncrement
+	eb := v.CurrentEpochEffectiveBalance
+	br := (eb / ebi) * (ebi * params.BeaconConfig().BaseRewardFactor / mathutil.IntegerSquareRoot(bal.ActiveCurrentEpoch))
+	activeCurrentEpochIncrements := bal.ActiveCurrentEpoch / ebi
+
+	r, p = uint64(0), uint64(0)
+	// Process source reward / penalty
+	if v.IsPrevEpochAttester && !v.IsSlashed {
+		if !helpers.IsInInactivityLeak(prevEpoch, finalizedEpoch) {
+			rewardNumerator := br * params.BeaconConfig().TimelySourceWeight * (bal.PrevEpochAttested / ebi)
+			r += rewardNumerator / (activeCurrentEpochIncrements * params.BeaconConfig().WeightDenominator)
+		}
+	} else {
+		p += br * params.BeaconConfig().TimelySourceWeight / params.BeaconConfig().WeightDenominator
+	}
+
+	// Process target reward / penalty
+	if v.IsPrevEpochTargetAttester && !v.IsSlashed {
+		if !helpers.IsInInactivityLeak(prevEpoch, finalizedEpoch) {
+			rewardNumerator := br * params.BeaconConfig().TimelyTargetWeight * (bal.PrevEpochTargetAttested / ebi)
+			r += rewardNumerator / (activeCurrentEpochIncrements * params.BeaconConfig().WeightDenominator)
+		}
+	} else {
+		p += br * params.BeaconConfig().TimelyTargetWeight / params.BeaconConfig().WeightDenominator
+	}
+
+	// Process head reward / penalty
+	if v.IsPrevEpochHeadAttester && !v.IsSlashed {
+		if !helpers.IsInInactivityLeak(prevEpoch, finalizedEpoch) {
+			rewardNumerator := br * params.BeaconConfig().TimelyHeadWeight * (bal.PrevEpochHeadAttested / ebi)
+			r += rewardNumerator / (activeCurrentEpochIncrements * params.BeaconConfig().WeightDenominator)
+		}
+	}
+
+	// Process finality delay penalty
+	// Apply an additional penalty to validators that did not vote on the correct target or slashed.
+	if !v.IsPrevEpochTargetAttester || v.IsSlashed {
+		penaltyNumerator := eb * v.InactivityScore
+		penaltyDenominator := params.BeaconConfig().InactivityScoreBias * params.BeaconConfig().InactivityPenaltyQuotientAltair
+		p += penaltyNumerator / penaltyDenominator
+	}
+
+	return r, p
+}

beacon-chain/core/altair/epoch_precompute_test.go

@@ -0,0 +1,283 @@
+package altair
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestInitializeEpochValidators_Ok(t *testing.T) {
+	ffe := params.BeaconConfig().FarFutureEpoch
+	s, err := stateAltair.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Slot: params.BeaconConfig().SlotsPerEpoch,
+		// Validator 0 is slashed
+		// Validator 1 is withdrawable
+		// Validator 2 is active prev epoch and current epoch
+		// Validator 3 is active prev epoch
+		Validators: []*ethpb.Validator{
+			{Slashed: true, WithdrawableEpoch: ffe, EffectiveBalance: 100},
+			{EffectiveBalance: 100},
+			{WithdrawableEpoch: ffe, ExitEpoch: ffe, EffectiveBalance: 100},
+			{WithdrawableEpoch: ffe, ExitEpoch: 1, EffectiveBalance: 100},
+		},
+		InactivityScores: []uint64{0, 1, 2, 3},
+	})
+	require.NoError(t, err)
+	v, b, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	assert.DeepEqual(t, &precompute.Validator{
+		IsSlashed:                    true,
+		CurrentEpochEffectiveBalance: 100,
+		InactivityScore:              0,
+	}, v[0], "Incorrect validator 0 status")
+	assert.DeepEqual(t, &precompute.Validator{
+		IsWithdrawableCurrentEpoch:   true,
+		CurrentEpochEffectiveBalance: 100,
+		InactivityScore:              1,
+	}, v[1], "Incorrect validator 1 status")
+	assert.DeepEqual(t, &precompute.Validator{
+		IsActivePrevEpoch:            true,
+		IsActiveCurrentEpoch:         true,
+		CurrentEpochEffectiveBalance: 100,
+		InactivityScore:              2,
+	}, v[2], "Incorrect validator 2 status")
+	assert.DeepEqual(t, &precompute.Validator{
+		IsActivePrevEpoch:            true,
+		CurrentEpochEffectiveBalance: 100,
+		InactivityScore:              3,
+	}, v[3], "Incorrect validator 3 status")
+
+	wantedBalances := &precompute.Balance{
+		ActiveCurrentEpoch: 100,
+		ActivePrevEpoch:    200,
+	}
+	assert.DeepEqual(t, wantedBalances, b, "Incorrect wanted balance")
+}
+
+func TestInitializeEpochValidators_BadState(t *testing.T) {
+	s, err := stateAltair.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators:       []*ethpb.Validator{{}},
+		InactivityScores: []uint64{},
+	})
+	require.NoError(t, err)
+	_, _, err = InitializeEpochValidators(context.Background(), s)
+	require.ErrorContains(t, "num of validators can't be greater than length of inactivity scores", err)
+}
+
+func TestProcessEpochParticipation(t *testing.T) {
+	s, err := testState()
+	require.NoError(t, err)
+	validators, balance, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	validators, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
+	require.NoError(t, err)
+	require.DeepEqual(t, &precompute.Validator{
+		IsActiveCurrentEpoch:         true,
+		IsActivePrevEpoch:            true,
+		IsWithdrawableCurrentEpoch:   true,
+		CurrentEpochEffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
+	}, validators[0])
+	require.DeepEqual(t, &precompute.Validator{
+		IsActiveCurrentEpoch:         true,
+		IsActivePrevEpoch:            true,
+		IsWithdrawableCurrentEpoch:   true,
+		CurrentEpochEffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
+		IsPrevEpochAttester:          true,
+	}, validators[1])
+	require.DeepEqual(t, &precompute.Validator{
+		IsActiveCurrentEpoch:         true,
+		IsActivePrevEpoch:            true,
+		IsWithdrawableCurrentEpoch:   true,
+		CurrentEpochEffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
+		IsPrevEpochAttester:          true,
+		IsCurrentEpochTargetAttester: true,
+		IsPrevEpochTargetAttester:    true,
+	}, validators[2])
+	require.DeepEqual(t, &precompute.Validator{
+		IsActiveCurrentEpoch:         true,
+		IsActivePrevEpoch:            true,
+		IsWithdrawableCurrentEpoch:   true,
+		CurrentEpochEffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
+		IsPrevEpochAttester:          true,
+		IsCurrentEpochTargetAttester: true,
+		IsPrevEpochTargetAttester:    true,
+		IsPrevEpochHeadAttester:      true,
+	}, validators[3])
+	require.Equal(t, params.BeaconConfig().MaxEffectiveBalance*3, balance.PrevEpochAttested)
+	require.Equal(t, balance.CurrentEpochTargetAttested, params.BeaconConfig().MaxEffectiveBalance*2)
+	require.Equal(t, balance.PrevEpochTargetAttested, params.BeaconConfig().MaxEffectiveBalance*2)
+	require.Equal(t, balance.PrevEpochHeadAttested, params.BeaconConfig().MaxEffectiveBalance*1)
+}
+
+func TestAttestationsDelta(t *testing.T) {
+	s, err := testState()
+	require.NoError(t, err)
+	validators, balance, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	validators, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
+	require.NoError(t, err)
+	rewards, penalties, err := AttestationsDelta(s, balance, validators)
+	require.NoError(t, err)
+
+	// Reward amount should increase as validator index increases due to setup.
+	for i := 1; i < len(rewards); i++ {
+		require.Equal(t, true, rewards[i] > rewards[i-1])
+	}
+
+	// Penalty amount should decrease as validator index increases due to setup.
+	for i := 1; i < len(penalties); i++ {
+		require.Equal(t, true, penalties[i] <= penalties[i-1])
+	}
+
+	// First index should have 0 reward.
+	require.Equal(t, uint64(0), rewards[0])
+	// Last index should have 0 penalty.
+	require.Equal(t, uint64(0), penalties[len(penalties)-1])
+}
+
+func TestProcessRewardsAndPenaltiesPrecompute_Ok(t *testing.T) {
+	s, err := testState()
+	require.NoError(t, err)
+	validators, balance, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	validators, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
+	require.NoError(t, err)
+	s, err = ProcessRewardsAndPenaltiesPrecompute(s, balance, validators)
+	require.NoError(t, err)
+
+	balances := s.Balances()
+	// Reward amount should increase as validator index increases due to setup.
+	for i := 1; i < len(balances); i++ {
+		require.Equal(t, true, balances[i] >= balances[i-1])
+	}
+
+	wanted := make([]uint64, s.NumValidators())
+	rewards, penalties, err := AttestationsDelta(s, balance, validators)
+	require.NoError(t, err)
+	for i := range rewards {
+		wanted[i] += rewards[i]
+	}
+	for i := range penalties {
+		if wanted[i] > penalties[i] {
+			wanted[i] -= penalties[i]
+		} else {
+			wanted[i] = 0
+		}
+	}
+	require.DeepEqual(t, wanted, balances)
+}
+
+func TestProcessRewardsAndPenaltiesPrecompute_InactivityLeak(t *testing.T) {
+	s, err := testState()
+	require.NoError(t, err)
+	validators, balance, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	validators, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
+	require.NoError(t, err)
+	sCopy := s.Copy()
+	s, err = ProcessRewardsAndPenaltiesPrecompute(s, balance, validators)
+	require.NoError(t, err)
+
+	// Copied state where finality happened long ago
+	require.NoError(t, sCopy.SetSlot(params.BeaconConfig().SlotsPerEpoch*1000))
+	sCopy, err = ProcessRewardsAndPenaltiesPrecompute(sCopy, balance, validators)
+	require.NoError(t, err)
+
+	balances := s.Balances()
+	inactivityBalances := sCopy.Balances()
+	// Balances should be much less in inactivity leak cases.
+	for i := 0; i < len(balances); i++ {
+		require.Equal(t, true, balances[i] >= inactivityBalances[i])
+	}
+}
+
+func TestProcessInactivityScores_CanProcess(t *testing.T) {
+	s, err := testState()
+	require.NoError(t, err)
+	defaultScore := uint64(5)
+	require.NoError(t, s.SetInactivityScores([]uint64{defaultScore, defaultScore, defaultScore, defaultScore}))
+	require.NoError(t, s.SetSlot(params.BeaconConfig().SlotsPerEpoch*types.Slot(params.BeaconConfig().MinEpochsToInactivityPenalty+2)))
+	validators, balance, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	validators, _, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
+	require.NoError(t, err)
+	s, _, err = ProcessInactivityScores(context.Background(), s, validators)
+	require.NoError(t, err)
+	inactivityScores, err := s.InactivityScores()
+	require.NoError(t, err)
+	// V0 and V1 didn't vote head. V2 and V3 did.
+	require.Equal(t, defaultScore+params.BeaconConfig().InactivityScoreBias, inactivityScores[0])
+	require.Equal(t, defaultScore+params.BeaconConfig().InactivityScoreBias, inactivityScores[1])
+	require.Equal(t, defaultScore-1, inactivityScores[2])
+	require.Equal(t, defaultScore-1, inactivityScores[3])
+}
+
+func TestProcessRewardsAndPenaltiesPrecompute_GenesisEpoch(t *testing.T) {
+	s, err := testState()
+	require.NoError(t, err)
+	validators, balance, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	validators, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
+	require.NoError(t, err)
+	require.NoError(t, s.SetSlot(0))
+	s, err = ProcessRewardsAndPenaltiesPrecompute(s, balance, validators)
+	require.NoError(t, err)
+
+	balances := s.Balances()
+	// Nothing should happen at genesis epoch
+	for i := 1; i < len(balances); i++ {
+		require.Equal(t, true, balances[i] == balances[i-1])
+	}
+}
+
+func TestProcessRewardsAndPenaltiesPrecompute_BadState(t *testing.T) {
+	s, err := testState()
+	require.NoError(t, err)
+	validators, balance, err := InitializeEpochValidators(context.Background(), s)
+	require.NoError(t, err)
+	_, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
+	require.NoError(t, err)
+	_, err = ProcessRewardsAndPenaltiesPrecompute(s, balance, []*precompute.Validator{})
+	require.ErrorContains(t, "validator registries not the same length as state's validator registries", err)
+}
+
+func testState() (state.BeaconState, error) {
+	generateParticipation := func(flags ...uint8) byte {
+		b := byte(0)
+		for _, flag := range flags {
+			b = AddValidatorFlag(b, flag)
+		}
+		return b
+	}
+	return stateAltair.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Slot: 2 * params.BeaconConfig().SlotsPerEpoch,
+		Validators: []*ethpb.Validator{
+			{EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance, ExitEpoch: params.BeaconConfig().FarFutureEpoch},
+			{EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance, ExitEpoch: params.BeaconConfig().FarFutureEpoch},
+			{EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance, ExitEpoch: params.BeaconConfig().FarFutureEpoch},
+			{EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance, ExitEpoch: params.BeaconConfig().FarFutureEpoch},
+		},
+		CurrentEpochParticipation: []byte{
+			0,
+			generateParticipation(params.BeaconConfig().TimelySourceFlagIndex),
+			generateParticipation(params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex),
+			generateParticipation(params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex, params.BeaconConfig().TimelyHeadFlagIndex),
+		},
+		PreviousEpochParticipation: []byte{
+			0,
+			generateParticipation(params.BeaconConfig().TimelySourceFlagIndex),
+			generateParticipation(params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex),
+			generateParticipation(params.BeaconConfig().TimelySourceFlagIndex, params.BeaconConfig().TimelyTargetFlagIndex, params.BeaconConfig().TimelyHeadFlagIndex),
+		},
+		InactivityScores: []uint64{0, 0, 0, 0},
+		Balances:         []uint64{0, 0, 0, 0},
+	})
+}

beacon-chain/core/altair/epoch_spec.go

@@ -0,0 +1,116 @@
+package altair
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/mathutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// ProcessSyncCommitteeUpdates  processes sync client committee updates for the beacon state.
+//
+// Spec code:
+// def process_sync_committee_updates(state: BeaconState) -> None:
+//    next_epoch = get_current_epoch(state) + Epoch(1)
+//    if next_epoch % EPOCHS_PER_SYNC_COMMITTEE_PERIOD == 0:
+//        state.current_sync_committee = state.next_sync_committee
+//        state.next_sync_committee = get_next_sync_committee(state)
+func ProcessSyncCommitteeUpdates(ctx context.Context, beaconState state.BeaconStateAltair) (state.BeaconStateAltair, error) {
+	nextEpoch := helpers.NextEpoch(beaconState)
+	if nextEpoch%params.BeaconConfig().EpochsPerSyncCommitteePeriod == 0 {
+		currentSyncCommittee, err := beaconState.NextSyncCommittee()
+		if err != nil {
+			return nil, err
+		}
+		if err := beaconState.SetCurrentSyncCommittee(currentSyncCommittee); err != nil {
+			return nil, err
+		}
+		nextCommittee, err := NextSyncCommittee(ctx, beaconState)
+		if err != nil {
+			return nil, err
+		}
+		if err := beaconState.SetNextSyncCommittee(nextCommittee); err != nil {
+			return nil, err
+		}
+		if err := helpers.UpdateSyncCommitteeCache(beaconState); err != nil {
+			return nil, err
+		}
+	}
+	return beaconState, nil
+}
+
+// ProcessParticipationFlagUpdates processes participation flag updates by rotating current to previous.
+//
+// Spec code:
+// def process_participation_flag_updates(state: BeaconState) -> None:
+//    state.previous_epoch_participation = state.current_epoch_participation
+//    state.current_epoch_participation = [ParticipationFlags(0b0000_0000) for _ in range(len(state.validators))]
+func ProcessParticipationFlagUpdates(beaconState state.BeaconStateAltair) (state.BeaconStateAltair, error) {
+	c, err := beaconState.CurrentEpochParticipation()
+	if err != nil {
+		return nil, err
+	}
+	if err := beaconState.SetPreviousParticipationBits(c); err != nil {
+		return nil, err
+	}
+	if err := beaconState.SetCurrentParticipationBits(make([]byte, beaconState.NumValidators())); err != nil {
+		return nil, err
+	}
+	return beaconState, nil
+}
+
+// ProcessSlashings processes the slashed validators during epoch processing,
+// The function is modified to use PROPORTIONAL_SLASHING_MULTIPLIER_ALTAIR.
+//
+// Spec code:
+//  def process_slashings(state: BeaconState) -> None:
+//    epoch = get_current_epoch(state)
+//    total_balance = get_total_active_balance(state)
+//    adjusted_total_slashing_balance = min(sum(state.slashings) * PROPORTIONAL_SLASHING_MULTIPLIER_ALTAIR, total_balance)
+//    for index, validator in enumerate(state.validators):
+//        if validator.slashed and epoch + EPOCHS_PER_SLASHINGS_VECTOR // 2 == validator.withdrawable_epoch:
+//            increment = EFFECTIVE_BALANCE_INCREMENT  # Factored out from penalty numerator to avoid uint64 overflow
+//            penalty_numerator = validator.effective_balance // increment * adjusted_total_slashing_balance
+//            penalty = penalty_numerator // total_balance * increment
+//            decrease_balance(state, ValidatorIndex(index), penalty)
+//            decrease_balance(state, ValidatorIndex(index), penalty)
+func ProcessSlashings(state state.BeaconState) (state.BeaconState, error) {
+	currentEpoch := helpers.CurrentEpoch(state)
+	totalBalance, err := helpers.TotalActiveBalance(state)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get total active balance")
+	}
+
+	// Compute slashed balances in the current epoch
+	exitLength := params.BeaconConfig().EpochsPerSlashingsVector
+
+	// Compute the sum of state slashings
+	slashings := state.Slashings()
+	totalSlashing := uint64(0)
+	for _, slashing := range slashings {
+		totalSlashing += slashing
+	}
+
+	// a callback is used here to apply the following actions  to all validators
+	// below equally.
+	increment := params.BeaconConfig().EffectiveBalanceIncrement
+	minSlashing := mathutil.Min(totalSlashing*params.BeaconConfig().ProportionalSlashingMultiplierAltair, totalBalance)
+	err = state.ApplyToEveryValidator(func(idx int, val *ethpb.Validator) (bool, *ethpb.Validator, error) {
+		correctEpoch := (currentEpoch + exitLength/2) == val.WithdrawableEpoch
+		if val.Slashed && correctEpoch {
+			penaltyNumerator := val.EffectiveBalance / increment * minSlashing
+			penalty := penaltyNumerator / totalBalance * increment
+			if err := helpers.DecreaseBalance(state, types.ValidatorIndex(idx), penalty); err != nil {
+				return false, val, err
+			}
+			return true, val, nil
+		}
+		return false, val, nil
+	})
+	return state, err
+}

beacon-chain/core/altair/epoch_spec_test.go

@@ -0,0 +1,181 @@
+package altair_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"google.golang.org/protobuf/proto"
+)
+
+func TestProcessSyncCommitteeUpdates_CanRotate(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().MaxValidatorsPerCommittee)
+	h := &ethpb.BeaconBlockHeader{
+		StateRoot:  bytesutil.PadTo([]byte{'a'}, 32),
+		ParentRoot: bytesutil.PadTo([]byte{'b'}, 32),
+		BodyRoot:   bytesutil.PadTo([]byte{'c'}, 32),
+	}
+	require.NoError(t, s.SetLatestBlockHeader(h))
+	postState, err := altair.ProcessSyncCommitteeUpdates(context.Background(), s)
+	require.NoError(t, err)
+	current, err := postState.CurrentSyncCommittee()
+	require.NoError(t, err)
+	next, err := postState.NextSyncCommittee()
+	require.NoError(t, err)
+	require.DeepEqual(t, current, next)
+
+	require.NoError(t, s.SetSlot(params.BeaconConfig().SlotsPerEpoch))
+	postState, err = altair.ProcessSyncCommitteeUpdates(context.Background(), s)
+	require.NoError(t, err)
+	c, err := postState.CurrentSyncCommittee()
+	require.NoError(t, err)
+	n, err := postState.NextSyncCommittee()
+	require.NoError(t, err)
+	require.DeepEqual(t, current, c)
+	require.DeepEqual(t, next, n)
+
+	require.NoError(t, s.SetSlot(types.Slot(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*params.BeaconConfig().SlotsPerEpoch-1))
+	postState, err = altair.ProcessSyncCommitteeUpdates(context.Background(), s)
+	require.NoError(t, err)
+	c, err = postState.CurrentSyncCommittee()
+	require.NoError(t, err)
+	n, err = postState.NextSyncCommittee()
+	require.NoError(t, err)
+	require.NotEqual(t, current, c)
+	require.NotEqual(t, next, n)
+	require.DeepEqual(t, next, c)
+
+	// Test boundary condition.
+	slot := params.BeaconConfig().SlotsPerEpoch * types.Slot(helpers.CurrentEpoch(s)+params.BeaconConfig().EpochsPerSyncCommitteePeriod)
+	require.NoError(t, s.SetSlot(slot))
+	boundaryCommittee, err := altair.NextSyncCommittee(context.Background(), s)
+	require.NoError(t, err)
+	require.DeepNotEqual(t, boundaryCommittee, n)
+}
+
+func TestProcessParticipationFlagUpdates_CanRotate(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().MaxValidatorsPerCommittee)
+	c, err := s.CurrentEpochParticipation()
+	require.NoError(t, err)
+	require.DeepEqual(t, make([]byte, params.BeaconConfig().MaxValidatorsPerCommittee), c)
+	p, err := s.PreviousEpochParticipation()
+	require.NoError(t, err)
+	require.DeepEqual(t, make([]byte, params.BeaconConfig().MaxValidatorsPerCommittee), p)
+
+	newC := []byte{'a'}
+	newP := []byte{'b'}
+	require.NoError(t, s.SetCurrentParticipationBits(newC))
+	require.NoError(t, s.SetPreviousParticipationBits(newP))
+	c, err = s.CurrentEpochParticipation()
+	require.NoError(t, err)
+	require.DeepEqual(t, newC, c)
+	p, err = s.PreviousEpochParticipation()
+	require.NoError(t, err)
+	require.DeepEqual(t, newP, p)
+
+	s, err = altair.ProcessParticipationFlagUpdates(s)
+	require.NoError(t, err)
+	c, err = s.CurrentEpochParticipation()
+	require.NoError(t, err)
+	require.DeepEqual(t, make([]byte, params.BeaconConfig().MaxValidatorsPerCommittee), c)
+	p, err = s.PreviousEpochParticipation()
+	require.NoError(t, err)
+	require.DeepEqual(t, newC, p)
+}
+
+func TestProcessSlashings_NotSlashed(t *testing.T) {
+	base := &ethpb.BeaconStateAltair{
+		Slot:       0,
+		Validators: []*ethpb.Validator{{Slashed: true}},
+		Balances:   []uint64{params.BeaconConfig().MaxEffectiveBalance},
+		Slashings:  []uint64{0, 1e9},
+	}
+	s, err := stateAltair.InitializeFromProto(base)
+	require.NoError(t, err)
+	newState, err := altair.ProcessSlashings(s)
+	require.NoError(t, err)
+	wanted := params.BeaconConfig().MaxEffectiveBalance
+	assert.Equal(t, wanted, newState.Balances()[0], "Unexpected slashed balance")
+}
+
+func TestProcessSlashings_SlashedLess(t *testing.T) {
+	tests := []struct {
+		state *ethpb.BeaconStateAltair
+		want  uint64
+	}{
+		{
+			state: &ethpb.BeaconStateAltair{
+				Validators: []*ethpb.Validator{
+					{Slashed: true,
+						WithdrawableEpoch: params.BeaconConfig().EpochsPerSlashingsVector / 2,
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance},
+					{ExitEpoch: params.BeaconConfig().FarFutureEpoch, EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance}},
+				Balances:  []uint64{params.BeaconConfig().MaxEffectiveBalance, params.BeaconConfig().MaxEffectiveBalance},
+				Slashings: []uint64{0, 1e9},
+			},
+			want: uint64(30000000000),
+		},
+		{
+			state: &ethpb.BeaconStateAltair{
+				Validators: []*ethpb.Validator{
+					{Slashed: true,
+						WithdrawableEpoch: params.BeaconConfig().EpochsPerSlashingsVector / 2,
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance},
+					{ExitEpoch: params.BeaconConfig().FarFutureEpoch, EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance},
+					{ExitEpoch: params.BeaconConfig().FarFutureEpoch, EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance},
+				},
+				Balances:  []uint64{params.BeaconConfig().MaxEffectiveBalance, params.BeaconConfig().MaxEffectiveBalance},
+				Slashings: []uint64{0, 1e9},
+			},
+			want: uint64(31000000000),
+		},
+		{
+			state: &ethpb.BeaconStateAltair{
+				Validators: []*ethpb.Validator{
+					{Slashed: true,
+						WithdrawableEpoch: params.BeaconConfig().EpochsPerSlashingsVector / 2,
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance},
+					{ExitEpoch: params.BeaconConfig().FarFutureEpoch, EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance},
+					{ExitEpoch: params.BeaconConfig().FarFutureEpoch, EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance},
+				},
+				Balances:  []uint64{params.BeaconConfig().MaxEffectiveBalance, params.BeaconConfig().MaxEffectiveBalance},
+				Slashings: []uint64{0, 2 * 1e9},
+			},
+			want: uint64(30000000000),
+		},
+		{
+			state: &ethpb.BeaconStateAltair{
+				Validators: []*ethpb.Validator{
+					{Slashed: true,
+						WithdrawableEpoch: params.BeaconConfig().EpochsPerSlashingsVector / 2,
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance - params.BeaconConfig().EffectiveBalanceIncrement},
+					{ExitEpoch: params.BeaconConfig().FarFutureEpoch, EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance - params.BeaconConfig().EffectiveBalanceIncrement}},
+				Balances:  []uint64{params.BeaconConfig().MaxEffectiveBalance - params.BeaconConfig().EffectiveBalanceIncrement, params.BeaconConfig().MaxEffectiveBalance - params.BeaconConfig().EffectiveBalanceIncrement},
+				Slashings: []uint64{0, 1e9},
+			},
+			want: uint64(29000000000),
+		},
+	}
+
+	for i, tt := range tests {
+		t.Run(fmt.Sprint(i), func(t *testing.T) {
+			helpers.ClearCache()
+			original := proto.Clone(tt.state)
+			s, err := stateAltair.InitializeFromProto(tt.state)
+			require.NoError(t, err)
+			newState, err := altair.ProcessSlashings(s)
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, newState.Balances()[0], "ProcessSlashings({%v}) = newState; newState.Balances[0] = %d", original, newState.Balances()[0])
+		})
+	}
+}

beacon-chain/core/altair/fork_transition.go

@@ -0,0 +1,115 @@
+package altair
+
+import (
+	"context"
+
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	statealtair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// UpgradeToAltair updates input state to return the version Altair state.
+func UpgradeToAltair(ctx context.Context, state state.BeaconState) (state.BeaconStateAltair, error) {
+	epoch := helpers.CurrentEpoch(state)
+
+	s := &ethpb.BeaconStateAltair{
+		GenesisTime:           state.GenesisTime(),
+		GenesisValidatorsRoot: state.GenesisValidatorRoot(),
+		Slot:                  state.Slot(),
+		Fork: &ethpb.Fork{
+			PreviousVersion: state.Fork().CurrentVersion,
+			CurrentVersion:  params.BeaconConfig().AltairForkVersion,
+			Epoch:           epoch,
+		},
+		LatestBlockHeader:           state.LatestBlockHeader(),
+		BlockRoots:                  state.BlockRoots(),
+		StateRoots:                  state.StateRoots(),
+		HistoricalRoots:             state.HistoricalRoots(),
+		Eth1Data:                    state.Eth1Data(),
+		Eth1DataVotes:               state.Eth1DataVotes(),
+		Eth1DepositIndex:            state.Eth1DepositIndex(),
+		Validators:                  state.Validators(),
+		Balances:                    state.Balances(),
+		RandaoMixes:                 state.RandaoMixes(),
+		Slashings:                   state.Slashings(),
+		PreviousEpochParticipation:  make([]byte, state.NumValidators()),
+		CurrentEpochParticipation:   make([]byte, state.NumValidators()),
+		JustificationBits:           state.JustificationBits(),
+		PreviousJustifiedCheckpoint: state.PreviousJustifiedCheckpoint(),
+		CurrentJustifiedCheckpoint:  state.CurrentJustifiedCheckpoint(),
+		FinalizedCheckpoint:         state.FinalizedCheckpoint(),
+		InactivityScores:            make([]uint64, state.NumValidators()),
+	}
+
+	newState, err := statealtair.InitializeFromProto(s)
+	if err != nil {
+		return nil, err
+	}
+
+	prevEpochAtts, err := state.PreviousEpochAttestations()
+	if err != nil {
+		return nil, err
+	}
+	newState, err = TranslateParticipation(newState, prevEpochAtts)
+	if err != nil {
+		return nil, err
+	}
+
+	committee, err := NextSyncCommittee(ctx, newState)
+	if err != nil {
+		return nil, err
+	}
+	if err := newState.SetCurrentSyncCommittee(committee); err != nil {
+		return nil, err
+	}
+	if err := newState.SetNextSyncCommittee(committee); err != nil {
+		return nil, err
+	}
+	return newState, nil
+}
+
+// TranslateParticipation translates pending attestations into participation bits, then inserts the bits into beacon state.
+// This is helper function t o convert phase 0 beacon state(pending attestations) to Altair beacon state(participation bits).
+func TranslateParticipation(state *statealtair.BeaconState, atts []*ethpb.PendingAttestation) (*statealtair.BeaconState, error) {
+	for _, att := range atts {
+		epochParticipation, err := state.PreviousEpochParticipation()
+		if err != nil {
+			return nil, err
+		}
+
+		participatedFlags, err := attestationParticipationFlagIndices(state, att.Data, att.InclusionDelay)
+		if err != nil {
+			return nil, err
+		}
+		committee, err := helpers.BeaconCommitteeFromState(state, att.Data.Slot, att.Data.CommitteeIndex)
+		if err != nil {
+			return nil, err
+		}
+		indices, err := attestationutil.AttestingIndices(att.AggregationBits, committee)
+		if err != nil {
+			return nil, err
+		}
+		sourceFlagIndex := params.BeaconConfig().TimelySourceFlagIndex
+		targetFlagIndex := params.BeaconConfig().TimelyTargetFlagIndex
+		headFlagIndex := params.BeaconConfig().TimelyHeadFlagIndex
+		for _, index := range indices {
+			if participatedFlags[sourceFlagIndex] && !HasValidatorFlag(epochParticipation[index], sourceFlagIndex) {
+				epochParticipation[index] = AddValidatorFlag(epochParticipation[index], sourceFlagIndex)
+			}
+			if participatedFlags[targetFlagIndex] && !HasValidatorFlag(epochParticipation[index], targetFlagIndex) {
+				epochParticipation[index] = AddValidatorFlag(epochParticipation[index], targetFlagIndex)
+			}
+			if participatedFlags[headFlagIndex] && !HasValidatorFlag(epochParticipation[index], headFlagIndex) {
+				epochParticipation[index] = AddValidatorFlag(epochParticipation[index], headFlagIndex)
+			}
+		}
+
+		if err := state.SetPreviousParticipationBits(epochParticipation); err != nil {
+			return nil, err
+		}
+	}
+	return state, nil
+}

beacon-chain/core/altair/fork_transition_test.go

@@ -0,0 +1,87 @@
+package altair_test
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestTranslateParticipation(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, 64)
+	st, ok := s.(*stateAltair.BeaconState)
+	require.Equal(t, true, ok)
+	require.NoError(t, st.SetSlot(st.Slot()+params.BeaconConfig().MinAttestationInclusionDelay))
+
+	var err error
+	newState, err := altair.TranslateParticipation(st, nil)
+	require.NoError(t, err)
+	participation, err := newState.PreviousEpochParticipation()
+	require.NoError(t, err)
+	require.DeepSSZEqual(t, make([]byte, 64), participation)
+
+	aggBits := bitfield.NewBitlist(2)
+	aggBits.SetBitAt(0, true)
+	aggBits.SetBitAt(1, true)
+	r, err := helpers.BlockRootAtSlot(s, 0)
+	require.NoError(t, err)
+	var pendingAtts []*ethpb.PendingAttestation
+	for i := 0; i < 3; i++ {
+		pendingAtts = append(pendingAtts, &ethpb.PendingAttestation{
+			Data: &ethpb.AttestationData{
+				CommitteeIndex:  types.CommitteeIndex(i),
+				BeaconBlockRoot: r,
+				Source:          &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+				Target:          &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+			},
+			AggregationBits: aggBits,
+			InclusionDelay:  1,
+		})
+	}
+
+	newState, err = altair.TranslateParticipation(newState, pendingAtts)
+	require.NoError(t, err)
+	participation, err = newState.PreviousEpochParticipation()
+	require.NoError(t, err)
+	require.DeepNotSSZEqual(t, make([]byte, 64), participation)
+
+	committee, err := helpers.BeaconCommitteeFromState(st, pendingAtts[0].Data.Slot, pendingAtts[0].Data.CommitteeIndex)
+	require.NoError(t, err)
+	indices, err := attestationutil.AttestingIndices(pendingAtts[0].AggregationBits, committee)
+	require.NoError(t, err)
+	for _, index := range indices {
+		require.Equal(t, true, altair.HasValidatorFlag(participation[index], params.BeaconConfig().TimelyHeadFlagIndex))
+		require.Equal(t, true, altair.HasValidatorFlag(participation[index], params.BeaconConfig().TimelyTargetFlagIndex))
+		require.Equal(t, true, altair.HasValidatorFlag(participation[index], params.BeaconConfig().TimelySourceFlagIndex))
+	}
+}
+
+func TestUpgradeToAltair(t *testing.T) {
+	st, _ := testutil.DeterministicGenesisState(t, params.BeaconConfig().MaxValidatorsPerCommittee)
+	aState, err := altair.UpgradeToAltair(context.Background(), st)
+	require.NoError(t, err)
+	_, ok := aState.(state.BeaconStateAltair)
+	require.Equal(t, true, ok)
+
+	f := aState.Fork()
+	require.DeepSSZEqual(t, &ethpb.Fork{
+		PreviousVersion: st.Fork().CurrentVersion,
+		CurrentVersion:  params.BeaconConfig().AltairForkVersion,
+		Epoch:           helpers.CurrentEpoch(st),
+	}, f)
+	csc, err := aState.CurrentSyncCommittee()
+	require.NoError(t, err)
+	nsc, err := aState.NextSyncCommittee()
+	require.NoError(t, err)
+	require.DeepSSZEqual(t, nsc, csc)
+}

beacon-chain/core/altair/reward.go

@@ -0,0 +1,51 @@
+package altair
+
+import (
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/shared/mathutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// BaseReward takes state and validator index and calculate
+// individual validator's base reward quotient.
+//
+// Spec code:
+//  def get_base_reward(state: BeaconState, index: ValidatorIndex) -> Gwei:
+//    """
+//    Return the base reward for the validator defined by ``index`` with respect to the current ``state``.
+//
+//    Note: An optimally performing validator can earn one base reward per epoch over a long time horizon.
+//    This takes into account both per-epoch (e.g. attestation) and intermittent duties (e.g. block proposal
+//    and sync committees).
+//    """
+//    increments = state.validators[index].effective_balance // EFFECTIVE_BALANCE_INCREMENT
+//    return Gwei(increments * get_base_reward_per_increment(state))
+func BaseReward(state state.ReadOnlyBeaconState, index types.ValidatorIndex) (uint64, error) {
+	totalBalance, err := helpers.TotalActiveBalance(state)
+	if err != nil {
+		return 0, errors.Wrap(err, "could not calculate active balance")
+	}
+	return BaseRewardWithTotalBalance(state, index, totalBalance)
+}
+
+// BaseRewardWithTotalBalance calculates the base reward with the provided total balance.
+func BaseRewardWithTotalBalance(state state.ReadOnlyBeaconState, index types.ValidatorIndex, totalBalance uint64) (uint64, error) {
+	val, err := state.ValidatorAtIndexReadOnly(index)
+	if err != nil {
+		return 0, err
+	}
+	increments := val.EffectiveBalance() / params.BeaconConfig().EffectiveBalanceIncrement
+	return increments * baseRewardPerIncrement(totalBalance), nil
+}
+
+// baseRewardPerIncrement of the beacon state
+//
+// Spec code:
+// def get_base_reward_per_increment(state: BeaconState) -> Gwei:
+//    return Gwei(EFFECTIVE_BALANCE_INCREMENT * BASE_REWARD_FACTOR // integer_squareroot(get_total_active_balance(state)))
+func baseRewardPerIncrement(activeBalance uint64) uint64 {
+	return params.BeaconConfig().EffectiveBalanceIncrement * params.BeaconConfig().BaseRewardFactor / mathutil.IntegerSquareRoot(activeBalance)
+}

beacon-chain/core/altair/reward_test.go

@@ -0,0 +1,28 @@
+package altair_test
+
+import (
+	"testing"
+
+	altair "github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestBaseReward(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisStateAltair(t, params.BeaconConfig().MaxValidatorsPerCommittee)
+	r0, err := altair.BaseReward(s, 0)
+	require.NoError(t, err)
+	r1, err := altair.BaseReward(s, 1)
+	require.NoError(t, err)
+	require.Equal(t, r0, r1)
+
+	v, err := s.ValidatorAtIndex(0)
+	require.NoError(t, err)
+	v.EffectiveBalance = v.EffectiveBalance + params.BeaconConfig().EffectiveBalanceIncrement
+	require.NoError(t, s.UpdateValidatorAtIndex(0, v))
+
+	r0, err = altair.BaseReward(s, 0)
+	require.NoError(t, err)
+	require.Equal(t, true, r0 > r1)
+}

beacon-chain/core/altair/sync_committee.go

@@ -2,6 +2,8 @@ package altair
 
 import (
 	"context"
+	"fmt"
+	"time"
 
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
@@ -170,7 +172,7 @@ func SyncSubCommitteePubkeys(syncCommittee *ethpb.SyncCommittee, subComIdx types
 //    modulo = max(1, SYNC_COMMITTEE_SIZE // SYNC_COMMITTEE_SUBNET_COUNT // TARGET_AGGREGATORS_PER_SYNC_SUBCOMMITTEE)
 //    return bytes_to_uint64(hash(signature)[0:8]) % modulo == 0
 func IsSyncCommitteeAggregator(sig []byte) (bool, error) {
-	if len(sig) != params.BeaconConfig().BLSPubkeyLength {
+	if len(sig) != params.BeaconConfig().BLSSignatureLength {
 		return false, errors.New("incorrect sig length")
 	}
 
@@ -179,3 +181,41 @@ func IsSyncCommitteeAggregator(sig []byte) (bool, error) {
 	hashedSig := hashutil.Hash(sig)
 	return bytesutil.FromBytes8(hashedSig[:8])%modulo == 0, nil
 }
+
+// Validate Sync Message to ensure that the provided slot is valid.
+func ValidateSyncMessageTime(slot types.Slot, genesisTime time.Time, clockDisparity time.Duration) error {
+	if err := helpers.ValidateSlotClock(slot, uint64(genesisTime.Unix())); err != nil {
+		return err
+	}
+	messageTime, err := helpers.SlotToTime(uint64(genesisTime.Unix()), slot)
+	if err != nil {
+		return err
+	}
+	currentSlot := helpers.SlotsSince(genesisTime)
+	slotStartTime, err := helpers.SlotToTime(uint64(genesisTime.Unix()), currentSlot)
+	if err != nil {
+		return err
+	}
+
+	lowestSlotBound := slotStartTime.Add(-clockDisparity)
+	currentLowerBound := time.Now().Add(-clockDisparity)
+	// In the event the Slot's start time, is before the
+	// current allowable bound, we set the slot's start
+	// time as the bound.
+	if slotStartTime.Before(currentLowerBound) {
+		lowestSlotBound = slotStartTime
+	}
+
+	lowerBound := lowestSlotBound
+	upperBound := time.Now().Add(clockDisparity)
+	// Verify sync message slot is within the time range.
+	if messageTime.Before(lowerBound) || messageTime.After(upperBound) {
+		return fmt.Errorf(
+			"sync message slot %d not within allowable range of %d to %d (current slot)",
+			slot,
+			lowerBound.Unix(),
+			upperBound.Unix(),
+		)
+	}
+	return nil
+}

beacon-chain/core/altair/sync_committee_test.go

@@ -3,6 +3,7 @@ package altair_test
 import (
 	"context"
 	"testing"
+	"time"
 
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
@@ -11,7 +12,9 @@ import (
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/bls"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 )
 
 func TestSyncCommitteeIndices_CanGet(t *testing.T) {
@@ -278,6 +281,107 @@ func TestSyncSubCommitteePubkeys_CanGet(t *testing.T) {
 
 }
 
+func Test_ValidateSyncMessageTime(t *testing.T) {
+	if params.BeaconNetworkConfig().MaximumGossipClockDisparity < 200*time.Millisecond {
+		t.Fatal("This test expects the maximum clock disparity to be at least 200ms")
+	}
+
+	type args struct {
+		syncMessageSlot types.Slot
+		genesisTime     time.Time
+	}
+	tests := []struct {
+		name      string
+		args      args
+		wantedErr string
+	}{
+		{
+			name: "sync_message.slot == current_slot",
+			args: args{
+				syncMessageSlot: 15,
+				genesisTime:     timeutils.Now().Add(-15 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second),
+			},
+		},
+		{
+			name: "sync_message.slot == current_slot, received in middle of slot",
+			args: args{
+				syncMessageSlot: 15,
+				genesisTime: timeutils.Now().Add(
+					-15 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second,
+				).Add(-(time.Duration(params.BeaconConfig().SecondsPerSlot/2) * time.Second)),
+			},
+		},
+		{
+			name: "sync_message.slot == current_slot, received 200ms early",
+			args: args{
+				syncMessageSlot: 16,
+				genesisTime: timeutils.Now().Add(
+					-16 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second,
+				).Add(-200 * time.Millisecond),
+			},
+		},
+		{
+			name: "sync_message.slot > current_slot",
+			args: args{
+				syncMessageSlot: 16,
+				genesisTime:     timeutils.Now().Add(-(15 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)),
+			},
+			wantedErr: "sync message slot 16 not within allowable range of",
+		},
+		{
+			name: "sync_message.slot == current_slot+CLOCK_DISPARITY",
+			args: args{
+				syncMessageSlot: 100,
+				genesisTime:     timeutils.Now().Add(-(100*time.Duration(params.BeaconConfig().SecondsPerSlot)*time.Second - params.BeaconNetworkConfig().MaximumGossipClockDisparity)),
+			},
+			wantedErr: "",
+		},
+		{
+			name: "sync_message.slot == current_slot+CLOCK_DISPARITY+200ms",
+			args: args{
+				syncMessageSlot: 100,
+				genesisTime:     timeutils.Now().Add(-(100*time.Duration(params.BeaconConfig().SecondsPerSlot)*time.Second - params.BeaconNetworkConfig().MaximumGossipClockDisparity - 200*time.Millisecond)),
+			},
+			wantedErr: "sync message slot 100 not within allowable range of",
+		},
+		{
+			name: "sync_message.slot == current_slot-CLOCK_DISPARITY",
+			args: args{
+				syncMessageSlot: 100,
+				genesisTime:     timeutils.Now().Add(-(100*time.Duration(params.BeaconConfig().SecondsPerSlot)*time.Second + params.BeaconNetworkConfig().MaximumGossipClockDisparity)),
+			},
+			wantedErr: "",
+		},
+		{
+			name: "sync_message.slot > current_slot+CLOCK_DISPARITY",
+			args: args{
+				syncMessageSlot: 101,
+				genesisTime:     timeutils.Now().Add(-(100*time.Duration(params.BeaconConfig().SecondsPerSlot)*time.Second + params.BeaconNetworkConfig().MaximumGossipClockDisparity)),
+			},
+			wantedErr: "sync message slot 101 not within allowable range of",
+		},
+		{
+			name: "sync_message.slot is well beyond current slot",
+			args: args{
+				syncMessageSlot: 1 << 32,
+				genesisTime:     timeutils.Now().Add(-15 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second),
+			},
+			wantedErr: "which exceeds max allowed value relative to the local clock",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := altair.ValidateSyncMessageTime(tt.args.syncMessageSlot, tt.args.genesisTime,
+				params.BeaconNetworkConfig().MaximumGossipClockDisparity)
+			if tt.wantedErr != "" {
+				assert.ErrorContains(t, tt.wantedErr, err)
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
+}
+
 func getState(t *testing.T, count uint64) *stateAltair.BeaconState {
 	validators := make([]*ethpb.Validator, count)
 	for i := 0; i < len(validators); i++ {

beacon-chain/core/altair/transition.go

@@ -0,0 +1,110 @@
+package altair
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	e "github.com/prysmaticlabs/prysm/beacon-chain/core/epoch"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"go.opencensus.io/trace"
+)
+
+// ProcessEpoch describes the per epoch operations that are performed on the beacon state.
+// It's optimized by pre computing validator attested info and epoch total/attested balances upfront.
+//
+// Spec code:
+// def process_epoch(state: BeaconState) -> None:
+//    process_justification_and_finalization(state)  # [Modified in Altair]
+//    process_inactivity_updates(state)  # [New in Altair]
+//    process_rewards_and_penalties(state)  # [Modified in Altair]
+//    process_registry_updates(state)
+//    process_slashings(state)  # [Modified in Altair]
+//    process_eth1_data_reset(state)
+//    process_effective_balance_updates(state)
+//    process_slashings_reset(state)
+//    process_randao_mixes_reset(state)
+//    process_historical_roots_update(state)
+//    process_participation_flag_updates(state)  # [New in Altair]
+//    process_sync_committee_updates(state)  # [New in Altair]
+func ProcessEpoch(ctx context.Context, state state.BeaconStateAltair) (state.BeaconStateAltair, error) {
+	ctx, span := trace.StartSpan(ctx, "altair.ProcessEpoch")
+	defer span.End()
+
+	if state == nil || state.IsNil() {
+		return nil, errors.New("nil state")
+	}
+	vp, bp, err := InitializeEpochValidators(ctx, state)
+	if err != nil {
+		return nil, err
+	}
+
+	// New in Altair.
+	vp, bp, err = ProcessEpochParticipation(ctx, state, bp, vp)
+	if err != nil {
+		return nil, err
+	}
+
+	state, err = precompute.ProcessJustificationAndFinalizationPreCompute(state, bp)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process justification")
+	}
+
+	// New in Altair.
+	state, vp, err = ProcessInactivityScores(ctx, state, vp)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process inactivity updates")
+	}
+
+	// New in Altair.
+	state, err = ProcessRewardsAndPenaltiesPrecompute(state, bp, vp)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process rewards and penalties")
+	}
+
+	state, err = e.ProcessRegistryUpdates(state)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process registry updates")
+	}
+
+	// Modified in Altair.
+	state, err = ProcessSlashings(state)
+	if err != nil {
+		return nil, err
+	}
+
+	state, err = e.ProcessEth1DataReset(state)
+	if err != nil {
+		return nil, err
+	}
+	state, err = e.ProcessEffectiveBalanceUpdates(state)
+	if err != nil {
+		return nil, err
+	}
+	state, err = e.ProcessSlashingsReset(state)
+	if err != nil {
+		return nil, err
+	}
+	state, err = e.ProcessRandaoMixesReset(state)
+	if err != nil {
+		return nil, err
+	}
+	state, err = e.ProcessHistoricalRootsUpdate(state)
+	if err != nil {
+		return nil, err
+	}
+
+	// New in Altair.
+	state, err = ProcessParticipationFlagUpdates(state)
+	if err != nil {
+		return nil, err
+	}
+
+	// New in Altair.
+	state, err = ProcessSyncCommitteeUpdates(ctx, state)
+	if err != nil {
+		return nil, err
+	}
+
+	return state, nil
+}

beacon-chain/core/altair/transition_test.go

@@ -0,0 +1,34 @@
+package altair_test
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestProcessEpoch_CanProcess(t *testing.T) {
+	epoch := types.Epoch(1)
+	slashing := make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector)
+	base := &ethpb.BeaconStateAltair{
+		Slot:                       params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epoch)) + 1,
+		BlockRoots:                 make([][]byte, 128),
+		Slashings:                  slashing,
+		RandaoMixes:                make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+		FinalizedCheckpoint:        &ethpb.Checkpoint{Root: make([]byte, 32)},
+		JustificationBits:          bitfield.Bitvector4{0x00},
+		CurrentJustifiedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)},
+	}
+	s, err := stateAltair.InitializeFromProto(base)
+	require.NoError(t, err)
+	require.NoError(t, s.SetValidators([]*ethpb.Validator{}))
+	newState, err := altair.ProcessEpoch(context.Background(), s)
+	require.NoError(t, err)
+	require.Equal(t, uint64(0), newState.Slashings()[2], "Unexpected slashed balance")
+}

beacon-chain/core/altair/validator.go

@@ -0,0 +1,86 @@
+package altair
+
+import (
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// SlashValidator with slashed index.
+// The function  is modified to use MIN_SLASHING_PENALTY_QUOTIENT_ALTAIR and use PROPOSER_WEIGHT when calculating the proposer reward.
+//
+// def slash_validator(state: BeaconState,
+//                    slashed_index: ValidatorIndex,
+//                    whistleblower_index: ValidatorIndex=None) -> None:
+//    """
+//    Slash the validator with index ``slashed_index``.
+//    """
+//    epoch = get_current_epoch(state)
+//    initiate_validator_exit(state, slashed_index)
+//    validator = state.validators[slashed_index]
+//    validator.slashed = True
+//    validator.withdrawable_epoch = max(validator.withdrawable_epoch, Epoch(epoch + EPOCHS_PER_SLASHINGS_VECTOR))
+//    state.slashings[epoch % EPOCHS_PER_SLASHINGS_VECTOR] += validator.effective_balance
+//    decrease_balance(state, slashed_index, validator.effective_balance // MIN_SLASHING_PENALTY_QUOTIENT_ALTAIR)
+//
+//    # Apply proposer and whistleblower rewards
+//    proposer_index = get_beacon_proposer_index(state)
+//    if whistleblower_index is None:
+//        whistleblower_index = proposer_index
+//    whistleblower_reward = Gwei(validator.effective_balance // WHISTLEBLOWER_REWARD_QUOTIENT)
+//    proposer_reward = Gwei(whistleblower_reward * PROPOSER_WEIGHT // WEIGHT_DENOMINATOR)
+//    increase_balance(state, proposer_index, proposer_reward)
+//    increase_balance(state, whistleblower_index, Gwei(whistleblower_reward - proposer_reward))
+func SlashValidator(state state.BeaconState, slashedIdx types.ValidatorIndex) (state.BeaconState, error) {
+	state, err := validators.InitiateValidatorExit(state, slashedIdx)
+	if err != nil {
+		return nil, errors.Wrapf(err, "could not initiate validator %d exit", slashedIdx)
+	}
+	currentEpoch := helpers.SlotToEpoch(state.Slot())
+	validator, err := state.ValidatorAtIndex(slashedIdx)
+	if err != nil {
+		return nil, err
+	}
+	validator.Slashed = true
+	maxWithdrawableEpoch := types.MaxEpoch(validator.WithdrawableEpoch, currentEpoch+params.BeaconConfig().EpochsPerSlashingsVector)
+	validator.WithdrawableEpoch = maxWithdrawableEpoch
+
+	if err := state.UpdateValidatorAtIndex(slashedIdx, validator); err != nil {
+		return nil, err
+	}
+
+	// The slashing amount is represented by epochs per slashing vector. The validator's effective balance is then applied to that amount.
+	slashings := state.Slashings()
+	currentSlashing := slashings[currentEpoch%params.BeaconConfig().EpochsPerSlashingsVector]
+	if err := state.UpdateSlashingsAtIndex(
+		uint64(currentEpoch%params.BeaconConfig().EpochsPerSlashingsVector),
+		currentSlashing+validator.EffectiveBalance,
+	); err != nil {
+		return nil, err
+	}
+	if err := helpers.DecreaseBalance(state, slashedIdx, validator.EffectiveBalance/params.BeaconConfig().MinSlashingPenaltyQuotientAltair); err != nil {
+		return nil, err
+	}
+
+	proposerIdx, err := helpers.BeaconProposerIndex(state)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get proposer idx")
+	}
+
+	// In this implementation, proposer is the whistleblower.
+	whistleBlowerIdx := proposerIdx
+	whistleblowerReward := validator.EffectiveBalance / params.BeaconConfig().WhistleBlowerRewardQuotient
+	proposerReward := whistleblowerReward * params.BeaconConfig().ProposerWeight / params.BeaconConfig().WeightDenominator
+	err = helpers.IncreaseBalance(state, proposerIdx, proposerReward)
+	if err != nil {
+		return nil, err
+	}
+	err = helpers.IncreaseBalance(state, whistleBlowerIdx, whistleblowerReward-proposerReward)
+	if err != nil {
+		return nil, err
+	}
+	return state, nil
+}

beacon-chain/core/altair/validator_test.go

@@ -0,0 +1,68 @@
+package altair_test
+
+import (
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	stateAltair "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestSlashValidator_OK(t *testing.T) {
+	validatorCount := params.BeaconConfig().MinGenesisActiveValidatorCount
+	registry := make([]*ethpb.Validator, 0, validatorCount)
+	balances := make([]uint64, 0, validatorCount)
+	for i := uint64(0); i < validatorCount; i++ {
+		registry = append(registry, &ethpb.Validator{
+			ActivationEpoch:  0,
+			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
+			EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
+		})
+		balances = append(balances, params.BeaconConfig().MaxEffectiveBalance)
+	}
+
+	base := &ethpb.BeaconStateAltair{
+		Validators:  registry,
+		Slashings:   make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector),
+		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+		Balances:    balances,
+	}
+	state, err := stateAltair.InitializeFromProto(base)
+	require.NoError(t, err)
+
+	slashedIdx := types.ValidatorIndex(2)
+
+	proposer, err := helpers.BeaconProposerIndex(state)
+	require.NoError(t, err, "Could not get proposer")
+	proposerBal, err := state.BalanceAtIndex(proposer)
+	require.NoError(t, err)
+	slashedState, err := altair.SlashValidator(state, slashedIdx)
+	require.NoError(t, err, "Could not slash validator")
+	state, ok := slashedState.(*stateAltair.BeaconState)
+	require.Equal(t, true, ok)
+
+	v, err := state.ValidatorAtIndex(slashedIdx)
+	require.NoError(t, err)
+	assert.Equal(t, true, v.Slashed, "Validator not slashed despite supposed to being slashed")
+	assert.Equal(t, helpers.CurrentEpoch(state)+params.BeaconConfig().EpochsPerSlashingsVector, v.WithdrawableEpoch, "Withdrawable epoch not the expected value")
+
+	maxBalance := params.BeaconConfig().MaxEffectiveBalance
+	slashedBalance := state.Slashings()[state.Slot().Mod(uint64(params.BeaconConfig().EpochsPerSlashingsVector))]
+	assert.Equal(t, maxBalance, slashedBalance, "Slashed balance isnt the expected amount")
+
+	whistleblowerReward := slashedBalance / params.BeaconConfig().WhistleBlowerRewardQuotient
+	bal, err := state.BalanceAtIndex(proposer)
+	require.NoError(t, err)
+	// The proposer is the whistleblower in phase 0.
+	assert.Equal(t, proposerBal+whistleblowerReward, bal, "Did not get expected balance for proposer")
+	bal, err = state.BalanceAtIndex(slashedIdx)
+	require.NoError(t, err)
+	v, err = state.ValidatorAtIndex(slashedIdx)
+	require.NoError(t, err)
+	assert.Equal(t, maxBalance-(v.EffectiveBalance/params.BeaconConfig().MinSlashingPenaltyQuotientAltair), bal, "Did not get expected balance for slashed validator")
+}

beacon-chain/core/blocks/BUILD.bazel

@@ -36,6 +36,7 @@ go_library(
         "//shared/depositutil:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/mathutil:go_default_library",
+        "//shared/p2putils:go_default_library",
         "//shared/params:go_default_library",
         "//shared/slashutil:go_default_library",
         "//shared/sliceutil:go_default_library",
@@ -65,6 +66,7 @@ go_test(
         "proposer_slashing_regression_test.go",
         "proposer_slashing_test.go",
         "randao_test.go",
+        "signature_test.go",
     ],
     data = glob(["testdata/**"]),
     embed = [":go_default_library"],

beacon-chain/core/blocks/signature.go

@@ -9,9 +9,10 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/p2putils"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
 
@@ -21,7 +22,7 @@ func signatureSet(signedData, pub, signature, domain []byte) (*bls.SignatureSet,
 	if err != nil {
 		return nil, errors.Wrap(err, "could not convert bytes to public key")
 	}
-	signingData := &statepb.SigningData{
+	signingData := &ethpb.SigningData{
 		ObjectRoot: signedData,
 		Domain:     domain,
 	}
@@ -77,6 +78,27 @@ func VerifyBlockSignature(beaconState state.ReadOnlyBeaconState,
 	return helpers.VerifyBlockSigningRoot(proposerPubKey, sig, domain, rootFunc)
 }
 
+// VerifyBlockSignatureUsingCurrentFork verifies the proposer signature of a beacon block. This differs
+// from the above method by not using fork data from the state and instead retrieving it
+// via the respective epoch.
+func VerifyBlockSignatureUsingCurrentFork(beaconState state.ReadOnlyBeaconState, blk block.SignedBeaconBlock) error {
+	currentEpoch := helpers.SlotToEpoch(blk.Block().Slot())
+	fork, err := p2putils.Fork(currentEpoch)
+	if err != nil {
+		return err
+	}
+	domain, err := helpers.Domain(fork, currentEpoch, params.BeaconConfig().DomainBeaconProposer, beaconState.GenesisValidatorRoot())
+	if err != nil {
+		return err
+	}
+	proposer, err := beaconState.ValidatorAtIndex(blk.Block().ProposerIndex())
+	if err != nil {
+		return err
+	}
+	proposerPubKey := proposer.PublicKey
+	return helpers.VerifyBlockSigningRoot(proposerPubKey, blk.Signature(), domain, blk.Block().HashTreeRoot)
+}
+
 // BlockSignatureSet retrieves the block signature set from the provided block and its corresponding state.
 func BlockSignatureSet(beaconState state.ReadOnlyBeaconState,
 	proposerIndex types.ValidatorIndex,

beacon-chain/core/blocks/signature_test.go

@@ -0,0 +1,41 @@
+package blocks_test
+
+import (
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	wrapperv2 "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestVerifyBlockSignatureUsingCurrentFork(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	bCfg := params.BeaconConfig()
+	bCfg.AltairForkEpoch = 100
+	bCfg.ForkVersionSchedule[bytesutil.ToBytes4(bCfg.AltairForkVersion)] = 100
+	params.OverrideBeaconConfig(bCfg)
+	bState, keys := testutil.DeterministicGenesisState(t, 100)
+	altairBlk := testutil.NewBeaconBlockAltair()
+	altairBlk.Block.ProposerIndex = 0
+	altairBlk.Block.Slot = params.BeaconConfig().SlotsPerEpoch * 100
+	fData := &ethpb.Fork{
+		Epoch:           100,
+		CurrentVersion:  params.BeaconConfig().AltairForkVersion,
+		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+	}
+	domain, err := helpers.Domain(fData, 100, params.BeaconConfig().DomainBeaconProposer, bState.GenesisValidatorRoot())
+	assert.NoError(t, err)
+	rt, err := helpers.ComputeSigningRoot(altairBlk.Block, domain)
+	assert.NoError(t, err)
+	sig := keys[0].Sign(rt[:]).Marshal()
+	altairBlk.Signature = sig
+	wsb, err := wrapperv2.WrappedAltairSignedBeaconBlock(altairBlk)
+	require.NoError(t, err)
+	assert.NoError(t, blocks.VerifyBlockSignatureUsingCurrentFork(bState, wsb))
+}

beacon-chain/core/helpers/BUILD.bazel

@@ -51,6 +51,7 @@ go_library(
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
     ],
 )
 
@@ -75,6 +76,7 @@ go_test(
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/v1:go_default_library",
+        "//beacon-chain/state/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//shared/bls:go_default_library",
         "//shared/bytesutil:go_default_library",

beacon-chain/core/helpers/committee.go

@@ -17,10 +17,12 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/sliceutil"
+	log "github.com/sirupsen/logrus"
 )
 
 var committeeCache = cache.NewCommitteesCache()
 var proposerIndicesCache = cache.NewProposerIndicesCache()
+var syncCommitteeCache = cache.NewSyncCommittee()
 
 // SlotCommitteeCount returns the number of crosslink committees of a slot. The
 // active validator count is provided as an argument rather than a imported implementation
@@ -271,26 +273,21 @@ func VerifyAttestationBitfieldLengths(state state.ReadOnlyBeaconState, att *ethp
 	return nil
 }
 
-// ShuffledIndices uses input beacon state and returns the shuffled indices of the input epoch,
-// the shuffled indices then can be used to break up into committees.
-func ShuffledIndices(s state.ReadOnlyBeaconState, epoch types.Epoch) ([]types.ValidatorIndex, error) {
-	seed, err := Seed(s, epoch, params.BeaconConfig().DomainBeaconAttester)
-	if err != nil {
-		return nil, errors.Wrapf(err, "could not get seed for epoch %d", epoch)
-	}
-
+// Returns the active indices and the total active balance of the validators in input `state` and during input `epoch`.
+func activeIndicesAndBalance(s state.ReadOnlyBeaconState, epoch types.Epoch) ([]types.ValidatorIndex, uint64, error) {
+	balances := uint64(0)
 	indices := make([]types.ValidatorIndex, 0, s.NumValidators())
 	if err := s.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
 		if IsActiveValidatorUsingTrie(val, epoch) {
+			balances += val.EffectiveBalance()
 			indices = append(indices, types.ValidatorIndex(idx))
 		}
 		return nil
 	}); err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 
-	// UnshuffleList is used as an optimized implementation for raw speed.
-	return UnshuffleList(indices, seed)
+	return indices, balances, nil
 }
 
 // UpdateCommitteeCache gets called at the beginning of every epoch to cache the committee shuffled indices
@@ -306,7 +303,13 @@ func UpdateCommitteeCache(state state.ReadOnlyBeaconState, epoch types.Epoch) er
 			return nil
 		}
 
-		shuffledIndices, err := ShuffledIndices(state, e)
+		indices, balance, err := activeIndicesAndBalance(state, e)
+		if err != nil {
+			return err
+		}
+
+		// Get the shuffled indices based on the seed.
+		shuffledIndices, err := UnshuffleList(indices, seed)
 		if err != nil {
 			return err
 		}
@@ -322,11 +325,23 @@ func UpdateCommitteeCache(state state.ReadOnlyBeaconState, epoch types.Epoch) er
 			return sortedIndices[i] < sortedIndices[j]
 		})
 
+		// Only update active balance field in cache if it's current epoch.
+		// Using current epoch state to update next epoch field will cause insert an invalid
+		// active balance value.
+		b := &cache.Balance{}
+		if e == epoch {
+			b = &cache.Balance{
+				Exist: true,
+				Total: balance,
+			}
+		}
+
 		if err := committeeCache.AddCommitteeShuffledList(&cache.Committees{
 			ShuffledIndices: shuffledIndices,
 			CommitteeCount:  uint64(params.BeaconConfig().SlotsPerEpoch.Mul(count)),
 			Seed:            seed,
 			SortedIndices:   sortedIndices,
+			ActiveBalance:   b,
 		}); err != nil {
 			return err
 		}
@@ -383,10 +398,200 @@ func UpdateProposerIndicesInCache(state state.ReadOnlyBeaconState) error {
 	})
 }
 
-// ClearCache clears the committee cache
+// ClearCache clears the beacon committee cache and sync committee cache.
 func ClearCache() {
 	committeeCache = cache.NewCommitteesCache()
 	proposerIndicesCache = cache.NewProposerIndicesCache()
+	syncCommitteeCache = cache.NewSyncCommittee()
+}
+
+// IsCurrentPeriodSyncCommittee returns true if the input validator index belongs in the current period sync committee
+// along with the sync committee root.
+// 1.) Checks if the public key exists in the sync committee cache
+// 2.) If 1 fails, checks if the public key exists in the input current sync committee object
+func IsCurrentPeriodSyncCommittee(
+	st state.BeaconStateAltair, valIdx types.ValidatorIndex,
+) (bool, error) {
+	root, err := syncPeriodBoundaryRoot(st)
+	if err != nil {
+		return false, err
+	}
+	indices, err := syncCommitteeCache.CurrentPeriodIndexPosition(bytesutil.ToBytes32(root), valIdx)
+	if err == cache.ErrNonExistingSyncCommitteeKey {
+		val, err := st.ValidatorAtIndex(valIdx)
+		if err != nil {
+			return false, nil
+		}
+		committee, err := st.CurrentSyncCommittee()
+		if err != nil {
+			return false, err
+		}
+
+		// Fill in the cache on miss.
+		go func() {
+			if err := syncCommitteeCache.UpdatePositionsInCommittee(bytesutil.ToBytes32(root), st); err != nil {
+				log.Errorf("Could not fill sync committee cache on miss: %v", err)
+			}
+		}()
+
+		return len(findSubCommitteeIndices(val.PublicKey, committee.Pubkeys)) > 0, nil
+	}
+	if err != nil {
+		return false, err
+	}
+	return len(indices) > 0, nil
+}
+
+// IsNextPeriodSyncCommittee returns true if the input validator index belongs in the next period sync committee
+// along with the sync period boundary root.
+// 1.) Checks if the public key exists in the sync committee cache
+// 2.) If 1 fails, checks if the public key exists in the input next sync committee object
+func IsNextPeriodSyncCommittee(
+	st state.BeaconStateAltair, valIdx types.ValidatorIndex,
+) (bool, error) {
+	root, err := syncPeriodBoundaryRoot(st)
+	if err != nil {
+		return false, err
+	}
+	indices, err := syncCommitteeCache.NextPeriodIndexPosition(bytesutil.ToBytes32(root), valIdx)
+	if err == cache.ErrNonExistingSyncCommitteeKey {
+		val, err := st.ValidatorAtIndex(valIdx)
+		if err != nil {
+			return false, nil
+		}
+		committee, err := st.NextSyncCommittee()
+		if err != nil {
+			return false, err
+		}
+		return len(findSubCommitteeIndices(val.PublicKey, committee.Pubkeys)) > 0, nil
+	}
+	if err != nil {
+		return false, err
+	}
+	return len(indices) > 0, nil
+}
+
+// CurrentPeriodSyncSubcommitteeIndices returns the subcommittee indices of the
+// current period sync committee for input validator.
+func CurrentPeriodSyncSubcommitteeIndices(
+	st state.BeaconStateAltair, valIdx types.ValidatorIndex,
+) ([]types.CommitteeIndex, error) {
+	root, err := syncPeriodBoundaryRoot(st)
+	if err != nil {
+		return nil, err
+	}
+	indices, err := syncCommitteeCache.CurrentPeriodIndexPosition(bytesutil.ToBytes32(root), valIdx)
+	if err == cache.ErrNonExistingSyncCommitteeKey {
+		val, err := st.ValidatorAtIndex(valIdx)
+		if err != nil {
+			return nil, nil
+		}
+		committee, err := st.CurrentSyncCommittee()
+		if err != nil {
+			return nil, err
+		}
+
+		// Fill in the cache on miss.
+		go func() {
+			if err := syncCommitteeCache.UpdatePositionsInCommittee(bytesutil.ToBytes32(root), st); err != nil {
+				log.Errorf("Could not fill sync committee cache on miss: %v", err)
+			}
+		}()
+
+		return findSubCommitteeIndices(val.PublicKey, committee.Pubkeys), nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return indices, nil
+}
+
+// NextPeriodSyncSubcommitteeIndices returns the subcommittee indices of the next period sync committee for input validator.
+func NextPeriodSyncSubcommitteeIndices(
+	st state.BeaconStateAltair, valIdx types.ValidatorIndex,
+) ([]types.CommitteeIndex, error) {
+	root, err := syncPeriodBoundaryRoot(st)
+	if err != nil {
+		return nil, err
+	}
+	indices, err := syncCommitteeCache.NextPeriodIndexPosition(bytesutil.ToBytes32(root), valIdx)
+	if err == cache.ErrNonExistingSyncCommitteeKey {
+		val, err := st.ValidatorAtIndex(valIdx)
+		if err != nil {
+			return nil, nil
+		}
+		committee, err := st.NextSyncCommittee()
+		if err != nil {
+			return nil, err
+		}
+		return findSubCommitteeIndices(val.PublicKey, committee.Pubkeys), nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return indices, nil
+}
+
+// UpdateSyncCommitteeCache updates sync committee cache.
+// It uses `state`'s latest block header root as key. To avoid miss usage, it disallows
+// block header with state root zeroed out.
+func UpdateSyncCommitteeCache(st state.BeaconStateAltair) error {
+	nextSlot := st.Slot() + 1
+	if nextSlot%params.BeaconConfig().SlotsPerEpoch != 0 {
+		return errors.New("not at the end of the epoch to update cache")
+	}
+	if SlotToEpoch(nextSlot)%params.BeaconConfig().EpochsPerSyncCommitteePeriod != 0 {
+		return errors.New("not at sync committee period boundary to update cache")
+	}
+
+	header := st.LatestBlockHeader()
+	if bytes.Equal(header.StateRoot, params.BeaconConfig().ZeroHash[:]) {
+		return errors.New("zero hash state root can't be used to update cache")
+	}
+
+	prevBlockRoot, err := header.HashTreeRoot()
+	if err != nil {
+		return err
+	}
+
+	return syncCommitteeCache.UpdatePositionsInCommittee(prevBlockRoot, st)
+}
+
+// Loop through `pubKeys` for matching `pubKey` and get the indices where it matches.
+func findSubCommitteeIndices(pubKey []byte, pubKeys [][]byte) []types.CommitteeIndex {
+	var indices []types.CommitteeIndex
+	for i, k := range pubKeys {
+		if bytes.Equal(k, pubKey) {
+			indices = append(indices, types.CommitteeIndex(i))
+		}
+	}
+	return indices
+}
+
+// Retrieve the current sync period boundary root by calculating sync period start epoch
+// and calling `BlockRoot`.
+// It uses the boundary slot - 1 for block root. (Ex: SlotsPerEpoch * EpochsPerSyncCommitteePeriod - 1)
+func syncPeriodBoundaryRoot(st state.ReadOnlyBeaconState) ([]byte, error) {
+	// Can't call `BlockRoot` until the first slot.
+	if st.Slot() == params.BeaconConfig().GenesisSlot {
+		return params.BeaconConfig().ZeroHash[:], nil
+	}
+
+	startEpoch, err := SyncCommitteePeriodStartEpoch(CurrentEpoch(st))
+	if err != nil {
+		return nil, err
+	}
+	startEpochSlot, err := StartSlot(startEpoch)
+	if err != nil {
+		return nil, err
+	}
+
+	// Prevent underflow
+	if startEpochSlot >= 1 {
+		startEpochSlot--
+	}
+
+	return BlockRootAtSlot(st, startEpochSlot)
 }
 
 // This computes proposer indices of the current epoch and returns a list of proposer indices,

beacon-chain/core/helpers/committee_test.go

@@ -2,15 +2,16 @@ package helpers
 
 import (
 	"fmt"
-	"reflect"
 	"strconv"
 	"testing"
+	"time"
 
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
+	v2 "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -35,7 +36,7 @@ func TestComputeCommittee_WithoutCache(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		Slot:        200,
 		BlockRoots:  make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot),
@@ -91,7 +92,7 @@ func TestVerifyBitfieldLength_OK(t *testing.T) {
 func TestCommitteeAssignments_CannotRetrieveFutureEpoch(t *testing.T) {
 	ClearCache()
 	epoch := types.Epoch(1)
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Slot: 0, // Epoch 0.
 	})
 	require.NoError(t, err)
@@ -111,7 +112,7 @@ func TestCommitteeAssignments_NoProposerForSlot0(t *testing.T) {
 			ExitEpoch:       params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		Slot:        2 * params.BeaconConfig().SlotsPerEpoch, // epoch 2
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -142,7 +143,7 @@ func TestCommitteeAssignments_CanRetrieve(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		Slot:        2 * params.BeaconConfig().SlotsPerEpoch, // epoch 2
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -219,7 +220,7 @@ func TestCommitteeAssignments_CannotRetrieveFuture(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		Slot:        2 * params.BeaconConfig().SlotsPerEpoch, // epoch 2
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -243,7 +244,7 @@ func TestCommitteeAssignments_EverySlotHasMin1Proposer(t *testing.T) {
 			ExitEpoch:       params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		Slot:        2 * params.BeaconConfig().SlotsPerEpoch, // epoch 2
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -280,7 +281,7 @@ func TestVerifyAttestationBitfieldLengths_OK(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: activeRoots,
 	})
@@ -368,38 +369,6 @@ func TestVerifyAttestationBitfieldLengths_OK(t *testing.T) {
 	}
 }
 
-func TestShuffledIndices_ShuffleRightLength(t *testing.T) {
-	valiatorCount := 1000
-	validators := make([]*ethpb.Validator, valiatorCount)
-	indices := make([]uint64, valiatorCount)
-	for i := 0; i < valiatorCount; i++ {
-		validators[i] = &ethpb.Validator{
-			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
-		}
-		indices[i] = uint64(i)
-	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
-		Validators:  validators,
-		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
-	})
-	require.NoError(t, err)
-	// Test for current epoch
-	shuffledIndices, err := ShuffledIndices(state, 0)
-	require.NoError(t, err)
-	assert.Equal(t, valiatorCount, len(shuffledIndices), "Incorrect shuffled indices count")
-	if reflect.DeepEqual(indices, shuffledIndices) {
-		t.Error("Shuffling did not happen")
-	}
-
-	// Test for next epoch
-	shuffledIndices, err = ShuffledIndices(state, 1)
-	require.NoError(t, err)
-	assert.Equal(t, valiatorCount, len(shuffledIndices), "Incorrect shuffled indices count")
-	if reflect.DeepEqual(indices, shuffledIndices) {
-		t.Error("Shuffling did not happen")
-	}
-}
-
 func TestUpdateCommitteeCache_CanUpdate(t *testing.T) {
 	ClearCache()
 	validatorCount := params.BeaconConfig().MinGenesisActiveValidatorCount
@@ -407,11 +376,12 @@ func TestUpdateCommitteeCache_CanUpdate(t *testing.T) {
 	indices := make([]types.ValidatorIndex, validatorCount)
 	for i := types.ValidatorIndex(0); uint64(i) < validatorCount; i++ {
 		validators[i] = &ethpb.Validator{
-			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
+			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
+			EffectiveBalance: 1,
 		}
 		indices[i] = i
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -426,6 +396,13 @@ func TestUpdateCommitteeCache_CanUpdate(t *testing.T) {
 	indices, err = committeeCache.Committee(params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epoch)), seed, idx)
 	require.NoError(t, err)
 	assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(indices)), "Did not save correct indices lengths")
+
+	// Total active balance should be `MinGenesisActiveValidatorCount` given each validator has effective balance of 1.
+	seed, err = Seed(state, 0, params.BeaconConfig().DomainBeaconAttester)
+	require.NoError(t, err)
+	balance, err := committeeCache.ActiveBalance(seed)
+	require.NoError(t, err)
+	require.Equal(t, validatorCount, balance)
 }
 
 func BenchmarkComputeCommittee300000_WithPreCache(b *testing.B) {
@@ -435,7 +412,7 @@ func BenchmarkComputeCommittee300000_WithPreCache(b *testing.B) {
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -469,7 +446,7 @@ func BenchmarkComputeCommittee3000000_WithPreCache(b *testing.B) {
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -503,7 +480,7 @@ func BenchmarkComputeCommittee128000_WithOutPreCache(b *testing.B) {
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -538,7 +515,7 @@ func BenchmarkComputeCommittee1000000_WithOutCache(b *testing.B) {
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -573,7 +550,7 @@ func BenchmarkComputeCommittee4000000_WithOutCache(b *testing.B) {
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -610,7 +587,7 @@ func TestBeaconCommitteeFromState_UpdateCacheForPreviousEpoch(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Slot:        params.BeaconConfig().SlotsPerEpoch,
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -635,7 +612,7 @@ func TestPrecomputeProposerIndices_Ok(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -659,3 +636,373 @@ func TestPrecomputeProposerIndices_Ok(t *testing.T) {
 	}
 	assert.DeepEqual(t, wantedProposerIndices, proposerIndices, "Did not precompute proposer indices correctly")
 }
+
+func TestIsCurrentEpochSyncCommittee_UsingCache(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ClearCache()
+	r := [32]byte{'a'}
+	require.NoError(t, err, syncCommitteeCache.UpdatePositionsInCommittee(r, state))
+
+	ok, err := IsCurrentPeriodSyncCommittee(state, 0)
+	require.NoError(t, err)
+	require.Equal(t, true, ok)
+}
+
+func TestIsCurrentEpochSyncCommittee_UsingCommittee(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ok, err := IsCurrentPeriodSyncCommittee(state, 0)
+	require.NoError(t, err)
+	require.Equal(t, true, ok)
+}
+
+func TestIsCurrentEpochSyncCommittee_DoesNotExist(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ok, err := IsCurrentPeriodSyncCommittee(state, 12390192)
+	require.NoError(t, err)
+	require.Equal(t, false, ok)
+}
+
+func TestIsNextEpochSyncCommittee_UsingCache(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ClearCache()
+	r := [32]byte{'a'}
+	require.NoError(t, err, syncCommitteeCache.UpdatePositionsInCommittee(r, state))
+
+	ok, err := IsNextPeriodSyncCommittee(state, 0)
+	require.NoError(t, err)
+	require.Equal(t, true, ok)
+}
+
+func TestIsNextEpochSyncCommittee_UsingCommittee(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ok, err := IsNextPeriodSyncCommittee(state, 0)
+	require.NoError(t, err)
+	require.Equal(t, true, ok)
+}
+
+func TestIsNextEpochSyncCommittee_DoesNotExist(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ok, err := IsNextPeriodSyncCommittee(state, 120391029)
+	require.NoError(t, err)
+	require.Equal(t, false, ok)
+}
+
+func TestCurrentEpochSyncSubcommitteeIndices_UsingCache(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ClearCache()
+	r := [32]byte{'a'}
+	require.NoError(t, err, syncCommitteeCache.UpdatePositionsInCommittee(r, state))
+
+	index, err := CurrentPeriodSyncSubcommitteeIndices(state, 0)
+	require.NoError(t, err)
+	require.DeepEqual(t, []types.CommitteeIndex{0}, index)
+}
+
+func TestCurrentEpochSyncSubcommitteeIndices_UsingCommittee(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	root, err := syncPeriodBoundaryRoot(state)
+	require.NoError(t, err)
+
+	// Test that cache was empty.
+	_, err = syncCommitteeCache.CurrentPeriodIndexPosition(bytesutil.ToBytes32(root), 0)
+	require.Equal(t, cache.ErrNonExistingSyncCommitteeKey, err)
+
+	// Test that helper can retrieve the index given empty cache.
+	index, err := CurrentPeriodSyncSubcommitteeIndices(state, 0)
+	require.NoError(t, err)
+	require.DeepEqual(t, []types.CommitteeIndex{0}, index)
+
+	// Test that cache was able to fill on miss.
+	time.Sleep(100 * time.Millisecond)
+	index, err = syncCommitteeCache.CurrentPeriodIndexPosition(bytesutil.ToBytes32(root), 0)
+	require.NoError(t, err)
+	require.DeepEqual(t, []types.CommitteeIndex{0}, index)
+}
+
+func TestCurrentEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
+	ClearCache()
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	index, err := CurrentPeriodSyncSubcommitteeIndices(state, 129301923)
+	require.NoError(t, err)
+	require.DeepEqual(t, []types.CommitteeIndex(nil), index)
+}
+
+func TestNextEpochSyncSubcommitteeIndices_UsingCache(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	ClearCache()
+	r := [32]byte{'a'}
+	require.NoError(t, err, syncCommitteeCache.UpdatePositionsInCommittee(r, state))
+
+	index, err := NextPeriodSyncSubcommitteeIndices(state, 0)
+	require.NoError(t, err)
+	require.DeepEqual(t, []types.CommitteeIndex{0}, index)
+}
+
+func TestNextEpochSyncSubcommitteeIndices_UsingCommittee(t *testing.T) {
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	index, err := NextPeriodSyncSubcommitteeIndices(state, 0)
+	require.NoError(t, err)
+	require.DeepEqual(t, []types.CommitteeIndex{0}, index)
+}
+
+func TestNextEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
+	ClearCache()
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys = append(syncCommittee.Pubkeys, bytesutil.PadTo(k, 48))
+	}
+
+	state, err := v2.InitializeFromProto(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+
+	index, err := NextPeriodSyncSubcommitteeIndices(state, 21093019)
+	require.NoError(t, err)
+	require.DeepEqual(t, []types.CommitteeIndex(nil), index)
+}
+
+func TestUpdateSyncCommitteeCache_BadSlot(t *testing.T) {
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
+		Slot: 1,
+	})
+	require.NoError(t, err)
+	err = UpdateSyncCommitteeCache(state)
+	require.ErrorContains(t, "not at the end of the epoch to update cache", err)
+
+	state, err = v1.InitializeFromProto(&ethpb.BeaconState{
+		Slot: params.BeaconConfig().SlotsPerEpoch - 1,
+	})
+	require.NoError(t, err)
+	err = UpdateSyncCommitteeCache(state)
+	require.ErrorContains(t, "not at sync committee period boundary to update cache", err)
+}
+
+func TestUpdateSyncCommitteeCache_BadRoot(t *testing.T) {
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
+		Slot:              types.Slot(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*params.BeaconConfig().SlotsPerEpoch - 1,
+		LatestBlockHeader: &ethpb.BeaconBlockHeader{StateRoot: params.BeaconConfig().ZeroHash[:]},
+	})
+	require.NoError(t, err)
+	err = UpdateSyncCommitteeCache(state)
+	require.ErrorContains(t, "zero hash state root can't be used to update cache", err)
+}

beacon-chain/core/helpers/rewards_penalties.go

@@ -1,7 +1,9 @@
 package helpers
 
 import (
+	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
@@ -47,8 +49,23 @@ func TotalBalance(state state.ReadOnlyValidators, indices []types.ValidatorIndex
 //    """
 //    return get_total_balance(state, set(get_active_validator_indices(state, get_current_epoch(state))))
 func TotalActiveBalance(s state.ReadOnlyBeaconState) (uint64, error) {
-	total := uint64(0)
+	// Check if the active balance exists in cache.
 	epoch := SlotToEpoch(s.Slot())
+
+	seed, err := Seed(s, epoch, params.BeaconConfig().DomainBeaconAttester)
+	if err != nil {
+		return 0, errors.Wrap(err, "could not get seed")
+	}
+	activeBalance, err := committeeCache.ActiveBalance(seed)
+	if err == nil {
+		return activeBalance, nil
+	}
+	if err != cache.ErrNonCommitteeKey {
+		return 0, errors.Wrap(err, "could not interface with committee cache")
+	}
+
+	// Cache miss. Manually compute the active balance and fill the cache.
+	total := uint64(0)
 	if err := s.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
 		if IsActiveValidatorUsingTrie(val, epoch) {
 			total += val.EffectiveBalance()
@@ -57,6 +74,7 @@ func TotalActiveBalance(s state.ReadOnlyBeaconState) (uint64, error) {
 	}); err != nil {
 		return 0, err
 	}
+
 	return total, nil
 }
 

beacon-chain/core/helpers/rewards_penalties_test.go

@@ -4,16 +4,16 @@ import (
 	"testing"
 
 	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )
 
 func TestTotalBalance_OK(t *testing.T) {
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{Validators: []*ethpb.Validator{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{Validators: []*ethpb.Validator{
 		{EffectiveBalance: 27 * 1e9}, {EffectiveBalance: 28 * 1e9},
 		{EffectiveBalance: 32 * 1e9}, {EffectiveBalance: 40 * 1e9},
 	}})
@@ -26,7 +26,7 @@ func TestTotalBalance_OK(t *testing.T) {
 }
 
 func TestTotalBalance_ReturnsEffectiveBalanceIncrement(t *testing.T) {
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{Validators: []*ethpb.Validator{}})
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{Validators: []*ethpb.Validator{}})
 	require.NoError(t, err)
 
 	balance := TotalBalance(state, []types.ValidatorIndex{})
@@ -35,7 +35,7 @@ func TestTotalBalance_ReturnsEffectiveBalanceIncrement(t *testing.T) {
 }
 
 func TestTotalActiveBalance_OK(t *testing.T) {
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{Validators: []*ethpb.Validator{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{Validators: []*ethpb.Validator{
 		{
 			EffectiveBalance: 32 * 1e9,
 			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
@@ -55,6 +55,14 @@ func TestTotalActiveBalance_OK(t *testing.T) {
 	}})
 	require.NoError(t, err)
 
+	// Validate that cache miss to start with.
+	epoch := SlotToEpoch(state.Slot())
+	seed, err := Seed(state, epoch, params.BeaconConfig().DomainBeaconAttester)
+	require.NoError(t, err)
+	_, err = committeeCache.ActiveBalance(seed)
+	require.Equal(t, cache.ErrNonCommitteeKey, err)
+
+	// Validate manual calculation passes.
 	balance, err := TotalActiveBalance(state)
 	assert.NoError(t, err)
 	wanted := state.Validators()[0].EffectiveBalance + state.Validators()[1].EffectiveBalance +
@@ -74,7 +82,7 @@ func TestGetBalance_OK(t *testing.T) {
 		{i: 2, b: []uint64{0, 0, 0}},
 	}
 	for _, test := range tests {
-		state, err := v1.InitializeFromProto(&statepb.BeaconState{Balances: test.b})
+		state, err := v1.InitializeFromProto(&ethpb.BeaconState{Balances: test.b})
 		require.NoError(t, err)
 		assert.Equal(t, test.b[test.i], state.Balances()[test.i], "Incorrect Validator balance")
 	}
@@ -92,7 +100,7 @@ func TestIncreaseBalance_OK(t *testing.T) {
 		{i: 2, b: []uint64{27 * 1e9, 28 * 1e9, 32 * 1e9}, nb: 33 * 1e9, eb: 65 * 1e9},
 	}
 	for _, test := range tests {
-		state, err := v1.InitializeFromProto(&statepb.BeaconState{
+		state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 			Validators: []*ethpb.Validator{
 				{EffectiveBalance: 4}, {EffectiveBalance: 4}, {EffectiveBalance: 4}},
 			Balances: test.b,
@@ -116,7 +124,7 @@ func TestDecreaseBalance_OK(t *testing.T) {
 		{i: 3, b: []uint64{27 * 1e9, 28 * 1e9, 1, 28 * 1e9}, nb: 28 * 1e9, eb: 0},
 	}
 	for _, test := range tests {
-		state, err := v1.InitializeFromProto(&statepb.BeaconState{
+		state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 			Validators: []*ethpb.Validator{
 				{EffectiveBalance: 4}, {EffectiveBalance: 4}, {EffectiveBalance: 4}, {EffectiveBalance: 3}},
 			Balances: test.b,
@@ -179,7 +187,7 @@ func TestIsInInactivityLeak(t *testing.T) {
 	assert.Equal(t, false, IsInInactivityLeak(prevEpoch, finalizedEpoch), "Wanted inactivity leak false")
 }
 
-func buildState(slot types.Slot, validatorCount uint64) *statepb.BeaconState {
+func buildState(slot types.Slot, validatorCount uint64) *ethpb.BeaconState {
 	validators := make([]*ethpb.Validator, validatorCount)
 	for i := 0; i < len(validators); i++ {
 		validators[i] = &ethpb.Validator{
@@ -205,7 +213,7 @@ func buildState(slot types.Slot, validatorCount uint64) *statepb.BeaconState {
 	for i := 0; i < len(latestRandaoMixes); i++ {
 		latestRandaoMixes[i] = params.BeaconConfig().ZeroHash[:]
 	}
-	return &statepb.BeaconState{
+	return &ethpb.BeaconState{
 		Slot:                        slot,
 		Balances:                    validatorBalances,
 		Validators:                  validators,

beacon-chain/core/helpers/slot_epoch.go

@@ -208,8 +208,8 @@ func PrevSlot(slot types.Slot) types.Slot {
 // Spec code:
 // def compute_sync_committee_period(epoch: Epoch) -> uint64:
 //    return epoch // EPOCHS_PER_SYNC_COMMITTEE_PERIOD
-func SyncCommitteePeriod(e types.Epoch) uint64 {
-	return uint64(e / params.BeaconConfig().EpochsPerSyncCommitteePeriod)
+func SyncCommitteePeriod(epoch types.Epoch) uint64 {
+	return uint64(epoch / params.BeaconConfig().EpochsPerSyncCommitteePeriod)
 }
 
 // SyncCommitteePeriodStartEpoch returns the start epoch of a sync committee period.

beacon-chain/core/helpers/validators_test.go

@@ -8,7 +8,6 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -45,7 +44,7 @@ func TestIsActiveValidatorUsingTrie_OK(t *testing.T) {
 		{a: 64, b: true},
 	}
 	val := &ethpb.Validator{ActivationEpoch: 10, ExitEpoch: 100}
-	beaconState, err := v1.InitializeFromProto(&statepb.BeaconState{Validators: []*ethpb.Validator{val}})
+	beaconState, err := v1.InitializeFromProto(&ethpb.BeaconState{Validators: []*ethpb.Validator{val}})
 	require.NoError(t, err)
 	for _, test := range tests {
 		readOnlyVal, err := beaconState.ValidatorAtIndexReadOnly(0)
@@ -210,7 +209,7 @@ func TestIsSlashableValidatorUsingTrie_OK(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		beaconState, err := v1.InitializeFromProto(&statepb.BeaconState{Validators: []*ethpb.Validator{test.validator}})
+		beaconState, err := v1.InitializeFromProto(&ethpb.BeaconState{Validators: []*ethpb.Validator{test.validator}})
 		require.NoError(t, err)
 		readOnlyVal, err := beaconState.ValidatorAtIndexReadOnly(0)
 		require.NoError(t, err)
@@ -234,7 +233,7 @@ func TestBeaconProposerIndex_OK(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		Slot:        0,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -293,7 +292,7 @@ func TestBeaconProposerIndex_BadState(t *testing.T) {
 		roots[i] = make([]byte, 32)
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		Slot:        0,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -317,7 +316,7 @@ func TestComputeProposerIndex_Compatibility(t *testing.T) {
 		}
 	}
 
-	state, err := v1.InitializeFromProto(&statepb.BeaconState{
+	state, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
@@ -364,7 +363,7 @@ func TestActiveValidatorCount_Genesis(t *testing.T) {
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
 	}
-	beaconState, err := v1.InitializeFromProto(&statepb.BeaconState{
+	beaconState, err := v1.InitializeFromProto(&ethpb.BeaconState{
 		Slot:        0,
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -400,7 +399,7 @@ func TestChurnLimit_OK(t *testing.T) {
 			}
 		}
 
-		beaconState, err := v1.InitializeFromProto(&statepb.BeaconState{
+		beaconState, err := v1.InitializeFromProto(&ethpb.BeaconState{
 			Slot:        1,
 			Validators:  validators,
 			RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -415,8 +414,8 @@ func TestChurnLimit_OK(t *testing.T) {
 }
 
 func TestDomain_OK(t *testing.T) {
-	state := &statepb.BeaconState{
-		Fork: &statepb.Fork{
+	state := &ethpb.BeaconState{
+		Fork: &ethpb.Fork{
 			Epoch:           3,
 			PreviousVersion: []byte{0, 0, 0, 2},
 			CurrentVersion:  []byte{0, 0, 0, 3},
@@ -445,7 +444,7 @@ func TestDomain_OK(t *testing.T) {
 func TestActiveValidatorIndices(t *testing.T) {
 	farFutureEpoch := params.BeaconConfig().FarFutureEpoch
 	type args struct {
-		state *statepb.BeaconState
+		state *ethpb.BeaconState
 		epoch types.Epoch
 	}
 	tests := []struct {
@@ -457,7 +456,7 @@ func TestActiveValidatorIndices(t *testing.T) {
 		{
 			name: "all_active_epoch_10",
 			args: args{
-				state: &statepb.BeaconState{
+				state: &ethpb.BeaconState{
 					RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 					Validators: []*ethpb.Validator{
 						{
@@ -481,7 +480,7 @@ func TestActiveValidatorIndices(t *testing.T) {
 		{
 			name: "some_active_epoch_10",
 			args: args{
-				state: &statepb.BeaconState{
+				state: &ethpb.BeaconState{
 					RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 					Validators: []*ethpb.Validator{
 						{
@@ -505,7 +504,7 @@ func TestActiveValidatorIndices(t *testing.T) {
 		{
 			name: "some_active_with_recent_new_epoch_10",
 			args: args{
-				state: &statepb.BeaconState{
+				state: &ethpb.BeaconState{
 					RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 					Validators: []*ethpb.Validator{
 						{
@@ -533,7 +532,7 @@ func TestActiveValidatorIndices(t *testing.T) {
 		{
 			name: "some_active_with_recent_new_epoch_10",
 			args: args{
-				state: &statepb.BeaconState{
+				state: &ethpb.BeaconState{
 					RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 					Validators: []*ethpb.Validator{
 						{
@@ -561,7 +560,7 @@ func TestActiveValidatorIndices(t *testing.T) {
 		{
 			name: "some_active_with_recent_new_epoch_10",
 			args: args{
-				state: &statepb.BeaconState{
+				state: &ethpb.BeaconState{
 					RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 					Validators: []*ethpb.Validator{
 						{
@@ -698,7 +697,7 @@ func TestComputeProposerIndex(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			bState := &statepb.BeaconState{Validators: tt.args.validators}
+			bState := &ethpb.BeaconState{Validators: tt.args.validators}
 			stTrie, err := v1.InitializeFromProtoUnsafe(bState)
 			require.NoError(t, err)
 			got, err := ComputeProposerIndex(stTrie, tt.args.indices, tt.args.seed)
@@ -739,20 +738,20 @@ func TestIsIsEligibleForActivation(t *testing.T) {
 	tests := []struct {
 		name      string
 		validator *ethpb.Validator
-		state     *statepb.BeaconState
+		state     *ethpb.BeaconState
 		want      bool
 	}{
 		{"Eligible",
 			&ethpb.Validator{ActivationEligibilityEpoch: 1, ActivationEpoch: params.BeaconConfig().FarFutureEpoch},
-			&statepb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Epoch: 2}},
+			&ethpb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Epoch: 2}},
 			true},
 		{"Not yet finalized",
 			&ethpb.Validator{ActivationEligibilityEpoch: 1, ActivationEpoch: params.BeaconConfig().FarFutureEpoch},
-			&statepb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}},
+			&ethpb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}},
 			false},
 		{"Incorrect activation epoch",
 			&ethpb.Validator{ActivationEligibilityEpoch: 1},
-			&statepb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Epoch: 2}},
+			&ethpb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Epoch: 2}},
 			false},
 	}
 	for _, tt := range tests {

beacon-chain/core/helpers/weak_subjectivity_test.go

@@ -192,6 +192,7 @@ func TestWeakSubjectivity_IsWithinWeakSubjectivityPeriod(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			helpers.ClearCache()
 			got, err := helpers.IsWithinWeakSubjectivityPeriod(tt.epoch, tt.genWsState(), tt.genWsCheckpoint())
 			if tt.wantedErr != "" {
 				assert.Equal(t, false, got)

beacon-chain/core/state/BUILD.bazel

@@ -26,6 +26,7 @@ go_library(
     ],
     deps = [
         "//beacon-chain/cache:go_default_library",
+        "//beacon-chain/core/altair:go_default_library",
         "//beacon-chain/core/blocks:go_default_library",
         "//beacon-chain/core/epoch:go_default_library",
         "//beacon-chain/core/epoch/precompute:go_default_library",
@@ -43,6 +44,7 @@ go_library(
         "//shared/mathutil:go_default_library",
         "//shared/params:go_default_library",
         "//shared/traceutil:go_default_library",
+        "//shared/version:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",
         "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
@@ -56,6 +58,7 @@ go_test(
     name = "go_default_test",
     size = "small",
     srcs = [
+        "altair_transition_no_verify_sig_test.go",
         "benchmarks_test.go",
         "skip_slot_cache_test.go",
         "state_fuzz_test.go",
@@ -71,8 +74,10 @@ go_test(
     embed = [":go_default_library"],
     shard_count = 3,
     deps = [
+        "//beacon-chain/core/altair:go_default_library",
         "//beacon-chain/core/blocks:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/p2p/types:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
@@ -81,6 +86,7 @@ go_test(
         "//shared/benchutil:go_default_library",
         "//shared/bls:go_default_library",
         "//shared/bytesutil:go_default_library",
+        "//shared/copyutil:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/params:go_default_library",
         "//shared/testutil:go_default_library",

beacon-chain/core/state/altair_transition_no_verify_sig_test.go

@@ -0,0 +1,221 @@
+package state_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	core "github.com/prysmaticlabs/prysm/beacon-chain/core/state"
+	p2pType "github.com/prysmaticlabs/prysm/beacon-chain/p2p/types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/copyutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestExecuteAltairStateTransitionNoVerify_FullProcess(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisStateAltair(t, 100)
+
+	syncCommittee, err := altair.NextSyncCommittee(context.Background(), beaconState)
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetCurrentSyncCommittee(syncCommittee))
+
+	eth1Data := &ethpb.Eth1Data{
+		DepositCount: 100,
+		DepositRoot:  bytesutil.PadTo([]byte{2}, 32),
+		BlockHash:    make([]byte, 32),
+	}
+	require.NoError(t, beaconState.SetSlot(params.BeaconConfig().SlotsPerEpoch-1))
+	e := beaconState.Eth1Data()
+	e.DepositCount = 100
+	require.NoError(t, beaconState.SetEth1Data(e))
+	bh := beaconState.LatestBlockHeader()
+	bh.Slot = beaconState.Slot()
+	require.NoError(t, beaconState.SetLatestBlockHeader(bh))
+	require.NoError(t, beaconState.SetEth1DataVotes([]*ethpb.Eth1Data{eth1Data}))
+
+	require.NoError(t, beaconState.SetSlot(beaconState.Slot()+1))
+	epoch := helpers.CurrentEpoch(beaconState)
+	randaoReveal, err := testutil.RandaoReveal(beaconState, epoch, privKeys)
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetSlot(beaconState.Slot()-1))
+
+	nextSlotState, err := core.ProcessSlots(context.Background(), beaconState.Copy(), beaconState.Slot()+1)
+	require.NoError(t, err)
+	parentRoot, err := nextSlotState.LatestBlockHeader().HashTreeRoot()
+	require.NoError(t, err)
+	proposerIdx, err := helpers.BeaconProposerIndex(nextSlotState)
+	require.NoError(t, err)
+	block := testutil.NewBeaconBlockAltair()
+	block.Block.ProposerIndex = proposerIdx
+	block.Block.Slot = beaconState.Slot() + 1
+	block.Block.ParentRoot = parentRoot[:]
+	block.Block.Body.RandaoReveal = randaoReveal
+	block.Block.Body.Eth1Data = eth1Data
+
+	syncBits := bitfield.NewBitvector512()
+	for i := range syncBits {
+		syncBits[i] = 0xff
+	}
+	indices, err := altair.NextSyncCommitteeIndices(context.Background(), beaconState)
+	require.NoError(t, err)
+	h := copyutil.CopyBeaconBlockHeader(beaconState.LatestBlockHeader())
+	prevStateRoot, err := beaconState.HashTreeRoot(context.Background())
+	require.NoError(t, err)
+	h.StateRoot = prevStateRoot[:]
+	pbr, err := h.HashTreeRoot()
+	require.NoError(t, err)
+	syncSigs := make([]bls.Signature, len(indices))
+	for i, indice := range indices {
+		b := p2pType.SSZBytes(pbr[:])
+		sb, err := helpers.ComputeDomainAndSign(beaconState, helpers.CurrentEpoch(beaconState), &b, params.BeaconConfig().DomainSyncCommittee, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		syncSigs[i] = sig
+	}
+	aggregatedSig := bls.AggregateSignatures(syncSigs).Marshal()
+	syncAggregate := &ethpb.SyncAggregate{
+		SyncCommitteeBits:      syncBits,
+		SyncCommitteeSignature: aggregatedSig,
+	}
+	block.Block.Body.SyncAggregate = syncAggregate
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	stateRoot, err := core.CalculateStateRoot(context.Background(), beaconState, wsb)
+	require.NoError(t, err)
+	block.Block.StateRoot = stateRoot[:]
+
+	c := beaconState.Copy()
+	sig, err := testutil.BlockSignatureAltair(c, block.Block, privKeys)
+	require.NoError(t, err)
+	block.Signature = sig.Marshal()
+
+	wsb, err = wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	set, _, err := core.ExecuteStateTransitionNoVerifyAnySig(context.Background(), beaconState, wsb)
+	require.NoError(t, err)
+	verified, err := set.Verify()
+	require.NoError(t, err)
+	require.Equal(t, true, verified, "Could not verify signature set")
+}
+
+func TestExecuteAltairStateTransitionNoVerifySignature_CouldNotVerifyStateRoot(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisStateAltair(t, 100)
+
+	syncCommittee, err := altair.NextSyncCommittee(context.Background(), beaconState)
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetCurrentSyncCommittee(syncCommittee))
+
+	eth1Data := &ethpb.Eth1Data{
+		DepositCount: 100,
+		DepositRoot:  bytesutil.PadTo([]byte{2}, 32),
+		BlockHash:    make([]byte, 32),
+	}
+	require.NoError(t, beaconState.SetSlot(params.BeaconConfig().SlotsPerEpoch-1))
+	e := beaconState.Eth1Data()
+	e.DepositCount = 100
+	require.NoError(t, beaconState.SetEth1Data(e))
+	bh := beaconState.LatestBlockHeader()
+	bh.Slot = beaconState.Slot()
+	require.NoError(t, beaconState.SetLatestBlockHeader(bh))
+	require.NoError(t, beaconState.SetEth1DataVotes([]*ethpb.Eth1Data{eth1Data}))
+
+	require.NoError(t, beaconState.SetSlot(beaconState.Slot()+1))
+	epoch := helpers.CurrentEpoch(beaconState)
+	randaoReveal, err := testutil.RandaoReveal(beaconState, epoch, privKeys)
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetSlot(beaconState.Slot()-1))
+
+	nextSlotState, err := core.ProcessSlots(context.Background(), beaconState.Copy(), beaconState.Slot()+1)
+	require.NoError(t, err)
+	parentRoot, err := nextSlotState.LatestBlockHeader().HashTreeRoot()
+	require.NoError(t, err)
+	proposerIdx, err := helpers.BeaconProposerIndex(nextSlotState)
+	require.NoError(t, err)
+	block := testutil.NewBeaconBlockAltair()
+	block.Block.ProposerIndex = proposerIdx
+	block.Block.Slot = beaconState.Slot() + 1
+	block.Block.ParentRoot = parentRoot[:]
+	block.Block.Body.RandaoReveal = randaoReveal
+	block.Block.Body.Eth1Data = eth1Data
+
+	syncBits := bitfield.NewBitvector512()
+	for i := range syncBits {
+		syncBits[i] = 0xff
+	}
+	indices, err := altair.NextSyncCommitteeIndices(context.Background(), beaconState)
+	require.NoError(t, err)
+	h := copyutil.CopyBeaconBlockHeader(beaconState.LatestBlockHeader())
+	prevStateRoot, err := beaconState.HashTreeRoot(context.Background())
+	require.NoError(t, err)
+	h.StateRoot = prevStateRoot[:]
+	pbr, err := h.HashTreeRoot()
+	require.NoError(t, err)
+	syncSigs := make([]bls.Signature, len(indices))
+	for i, indice := range indices {
+		b := p2pType.SSZBytes(pbr[:])
+		sb, err := helpers.ComputeDomainAndSign(beaconState, helpers.CurrentEpoch(beaconState), &b, params.BeaconConfig().DomainSyncCommittee, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		syncSigs[i] = sig
+	}
+	aggregatedSig := bls.AggregateSignatures(syncSigs).Marshal()
+	syncAggregate := &ethpb.SyncAggregate{
+		SyncCommitteeBits:      syncBits,
+		SyncCommitteeSignature: aggregatedSig,
+	}
+	block.Block.Body.SyncAggregate = syncAggregate
+
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	stateRoot, err := core.CalculateStateRoot(context.Background(), beaconState, wsb)
+	require.NoError(t, err)
+	block.Block.StateRoot = stateRoot[:]
+
+	c := beaconState.Copy()
+	sig, err := testutil.BlockSignatureAltair(c, block.Block, privKeys)
+	require.NoError(t, err)
+	block.Signature = sig.Marshal()
+
+	block.Block.StateRoot = bytesutil.PadTo([]byte{'a'}, 32)
+	wsb, err = wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	_, _, err = core.ExecuteStateTransitionNoVerifyAnySig(context.Background(), beaconState, wsb)
+	require.ErrorContains(t, "could not validate state root", err)
+}
+
+func TestExecuteStateTransitionNoVerifyAnySig_PassesProcessingConditions(t *testing.T) {
+	beaconState, block := createFullAltairBlockWithOperations(t)
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	set, _, err := core.ExecuteStateTransitionNoVerifyAnySig(context.Background(), beaconState, wsb)
+	require.NoError(t, err)
+	// Test Signature set verifies.
+	verified, err := set.Verify()
+	require.NoError(t, err)
+	require.Equal(t, true, verified, "Could not verify signature set")
+}
+
+func createFullAltairBlockWithOperations(t *testing.T) (state.BeaconStateAltair,
+	*ethpb.SignedBeaconBlockAltair) {
+	beaconState, privKeys := testutil.DeterministicGenesisStateAltair(t, 32)
+	sCom, err := altair.NextSyncCommittee(context.Background(), beaconState)
+	assert.NoError(t, err)
+	assert.NoError(t, beaconState.SetCurrentSyncCommittee(sCom))
+	tState := beaconState.Copy()
+	blk, err := testutil.GenerateFullBlockAltair(tState, privKeys,
+		&testutil.BlockGenConfig{NumAttestations: 1, NumVoluntaryExits: 0, NumDeposits: 0}, 1)
+	require.NoError(t, err)
+
+	return beaconState, blk
+}

beacon-chain/core/state/skip_slot_cache.go

@@ -19,7 +19,7 @@ var SkipSlotCache = cache.NewSkipSlotCache()
 // The key for skip slot cache is mixed between state root and state slot.
 // state root is in the mix to defend against different forks with same skip slots
 // to hit the same cache. We don't want beacon states mixed up between different chains.
-func cacheKey(ctx context.Context, state state.ReadOnlyBeaconState) ([32]byte, error) {
+func CacheKey(ctx context.Context, state state.ReadOnlyBeaconState) ([32]byte, error) {
 	bh := state.LatestBlockHeader()
 	if bh == nil {
 		return [32]byte{}, errors.New("block head in state can't be nil")

beacon-chain/core/state/state_test.go

@@ -8,7 +8,6 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
@@ -42,7 +41,7 @@ func TestGenesisBeaconState_OK(t *testing.T) {
 
 	// Misc fields checks.
 	assert.Equal(t, types.Slot(0), newState.Slot(), "Slot was not correctly initialized")
-	if !proto.Equal(newState.Fork(), &statepb.Fork{
+	if !proto.Equal(newState.Fork(), &ethpb.Fork{
 		PreviousVersion: genesisForkVersion,
 		CurrentVersion:  genesisForkVersion,
 		Epoch:           genesisEpoch,
@@ -76,10 +75,10 @@ func TestGenesisBeaconState_OK(t *testing.T) {
 	assert.DeepEqual(t, make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector), newState.Slashings(), "Slashings was not correctly initialized")
 	currAtt, err := newState.CurrentEpochAttestations()
 	require.NoError(t, err)
-	assert.DeepSSZEqual(t, []*statepb.PendingAttestation{}, currAtt, "CurrentEpochAttestations was not correctly initialized")
+	assert.DeepSSZEqual(t, []*ethpb.PendingAttestation{}, currAtt, "CurrentEpochAttestations was not correctly initialized")
 	prevAtt, err := newState.CurrentEpochAttestations()
 	require.NoError(t, err)
-	assert.DeepSSZEqual(t, []*statepb.PendingAttestation{}, prevAtt, "PreviousEpochAttestations was not correctly initialized")
+	assert.DeepSSZEqual(t, []*ethpb.PendingAttestation{}, prevAtt, "PreviousEpochAttestations was not correctly initialized")
 
 	zeroHash := params.BeaconConfig().ZeroHash[:]
 	// History root checks.

beacon-chain/core/state/transition.go

@@ -11,6 +11,7 @@ import (
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
 	b "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	e "github.com/prysmaticlabs/prysm/beacon-chain/core/epoch"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
@@ -21,6 +22,7 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/mathutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/traceutil"
+	"github.com/prysmaticlabs/prysm/shared/version"
 	"go.opencensus.io/trace"
 )
 
@@ -221,7 +223,7 @@ func ProcessSlots(ctx context.Context, state state.BeaconState, slot types.Slot)
 	}
 
 	highestSlot := state.Slot()
-	key, err := cacheKey(ctx, state)
+	key, err := CacheKey(ctx, state)
 	if err != nil {
 		return nil, err
 	}
@@ -272,16 +274,35 @@ func ProcessSlots(ctx context.Context, state state.BeaconState, slot types.Slot)
 			return nil, errors.Wrap(err, "could not process slot")
 		}
 		if CanProcessEpoch(state) {
-			state, err = ProcessEpochPrecompute(ctx, state)
-			if err != nil {
-				traceutil.AnnotateError(span, err)
-				return nil, errors.Wrap(err, "could not process epoch with optimizations")
+			switch state.Version() {
+			case version.Phase0:
+				state, err = ProcessEpochPrecompute(ctx, state)
+				if err != nil {
+					traceutil.AnnotateError(span, err)
+					return nil, errors.Wrap(err, "could not process epoch with optimizations")
+				}
+			case version.Altair:
+				state, err = altair.ProcessEpoch(ctx, state)
+				if err != nil {
+					traceutil.AnnotateError(span, err)
+					return nil, errors.Wrap(err, "could not process epoch")
+				}
+			default:
+				return nil, errors.New("beacon state should have a version")
 			}
 		}
 		if err := state.SetSlot(state.Slot() + 1); err != nil {
 			traceutil.AnnotateError(span, err)
 			return nil, errors.Wrap(err, "failed to increment state slot")
 		}
+
+		// Transition to Altair state.
+		if helpers.IsEpochStart(state.Slot()) && helpers.SlotToEpoch(state.Slot()) == params.BeaconConfig().AltairForkEpoch {
+			state, err = altair.UpgradeToAltair(ctx, state)
+			if err != nil {
+				return nil, err
+			}
+		}
 	}
 
 	if highestSlot < state.Slot() {

beacon-chain/core/state/transition_no_verify_sig.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 
 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
 	b "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state/interop"
@@ -15,6 +16,7 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/bls"
 	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/traceutil"
+	"github.com/prysmaticlabs/prysm/shared/version"
 	"go.opencensus.io/trace"
 )
 
@@ -150,6 +152,16 @@ func CalculateStateRoot(
 	if err != nil {
 		return [32]byte{}, errors.Wrap(err, "could not process block")
 	}
+	if signed.Version() == version.Altair {
+		sa, err := signed.Block().Body().SyncAggregate()
+		if err != nil {
+			return [32]byte{}, err
+		}
+		state, err = altair.ProcessSyncAggregate(state, sa)
+		if err != nil {
+			return [32]byte{}, err
+		}
+	}
 
 	return state.HashTreeRoot(ctx)
 }
@@ -182,6 +194,16 @@ func ProcessBlockNoVerifyAnySig(
 	if err != nil {
 		return nil, nil, err
 	}
+	if signed.Version() == version.Altair {
+		sa, err := signed.Block().Body().SyncAggregate()
+		if err != nil {
+			return nil, nil, err
+		}
+		state, err = altair.ProcessSyncAggregate(state, sa)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
 
 	bSet, err := b.BlockSignatureSet(state, blk.ProposerIndex(), signed.Signature(), blk.HashTreeRoot)
 	if err != nil {
@@ -240,22 +262,22 @@ func ProcessOperationsNoVerifyAttsSigs(
 		return nil, errors.Wrap(err, "could not verify operation lengths")
 	}
 
-	state, err := b.ProcessProposerSlashings(ctx, state, signedBeaconBlock.Block().Body().ProposerSlashings(), v.SlashValidator)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not process block proposer slashings")
-	}
-	state, err = b.ProcessAttesterSlashings(ctx, state, signedBeaconBlock.Block().Body().AttesterSlashings(), v.SlashValidator)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not process block attester slashings")
-	}
-	state, err = b.ProcessAttestationsNoVerifySignature(ctx, state, signedBeaconBlock)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not process block attestations")
-	}
-	state, err = b.ProcessDeposits(ctx, state, signedBeaconBlock.Block().Body().Deposits())
-	if err != nil {
-		return nil, errors.Wrap(err, "could not process block validator deposits")
+	var err error
+	switch signedBeaconBlock.Version() {
+	case version.Phase0:
+		state, err = phase0Operations(ctx, state, signedBeaconBlock)
+		if err != nil {
+			return nil, err
+		}
+	case version.Altair:
+		state, err = altairOperations(ctx, state, signedBeaconBlock)
+		if err != nil {
+			return nil, err
+		}
+	default:
+		return nil, errors.New("block does not have correct version")
 	}
+
 	state, err = b.ProcessVoluntaryExits(ctx, state, signedBeaconBlock.Block().Body().VoluntaryExits())
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process validator exits")
@@ -309,3 +331,43 @@ func ProcessBlockForStateRoot(
 
 	return state, nil
 }
+
+// This calls altair specific block operations.
+func altairOperations(
+	ctx context.Context,
+	state state.BeaconState,
+	signedBeaconBlock block.SignedBeaconBlock) (state.BeaconState, error) {
+	state, err := b.ProcessProposerSlashings(ctx, state, signedBeaconBlock.Block().Body().ProposerSlashings(), altair.SlashValidator)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process block proposer slashings")
+	}
+	state, err = b.ProcessAttesterSlashings(ctx, state, signedBeaconBlock.Block().Body().AttesterSlashings(), altair.SlashValidator)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process block attester slashings")
+	}
+	state, err = altair.ProcessAttestationsNoVerifySignature(ctx, state, signedBeaconBlock)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process block attestations")
+	}
+	return altair.ProcessDeposits(ctx, state, signedBeaconBlock.Block().Body().Deposits())
+}
+
+// This calls phase 0 specific block operations.
+func phase0Operations(
+	ctx context.Context,
+	state state.BeaconStateAltair,
+	signedBeaconBlock block.SignedBeaconBlock) (state.BeaconState, error) {
+	state, err := b.ProcessProposerSlashings(ctx, state, signedBeaconBlock.Block().Body().ProposerSlashings(), v.SlashValidator)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process block proposer slashings")
+	}
+	state, err = b.ProcessAttesterSlashings(ctx, state, signedBeaconBlock.Block().Body().AttesterSlashings(), v.SlashValidator)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process block attester slashings")
+	}
+	state, err = b.ProcessAttestationsNoVerifySignature(ctx, state, signedBeaconBlock)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process block attestations")
+	}
+	return b.ProcessDeposits(ctx, state, signedBeaconBlock.Block().Body().Deposits())
+}

beacon-chain/core/state/transition_test.go

@@ -14,7 +14,6 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/bls"
@@ -33,7 +32,7 @@ func init() {
 }
 
 func TestExecuteStateTransition_IncorrectSlot(t *testing.T) {
-	base := &statepb.BeaconState{
+	base := &ethpb.BeaconState{
 		Slot: 5,
 	}
 	beaconState, err := v1.InitializeFromProto(base)
@@ -243,7 +242,7 @@ func TestProcessBlock_IncorrectProcessExits(t *testing.T) {
 	cp := beaconState.CurrentJustifiedCheckpoint()
 	cp.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cp))
-	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&statepb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&ethpb.PendingAttestation{}))
 	_, err = core.VerifyOperationLengths(context.Background(), beaconState, wrapper.WrappedPhase0SignedBeaconBlock(block))
 	wanted := "number of voluntary exits (17) in block body exceeds allowed threshold of 16"
 	assert.ErrorContains(t, wanted, err)
@@ -269,7 +268,7 @@ func createFullBlockWithOperations(t *testing.T) (state.BeaconState,
 	copy(mockRoot[:], "hello-world")
 	cp.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cp))
-	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&statepb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&ethpb.PendingAttestation{}))
 
 	proposerSlashIdx := types.ValidatorIndex(3)
 	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
@@ -445,9 +444,9 @@ func TestProcessBlock_PassesProcessingConditions(t *testing.T) {
 func TestProcessEpochPrecompute_CanProcess(t *testing.T) {
 	epoch := types.Epoch(1)
 
-	atts := []*statepb.PendingAttestation{{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: make([]byte, 32)}}, InclusionDelay: 1}}
+	atts := []*ethpb.PendingAttestation{{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: make([]byte, 32)}}, InclusionDelay: 1}}
 	slashing := make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector)
-	base := &statepb.BeaconState{
+	base := &ethpb.BeaconState{
 		Slot:                       params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epoch)) + 1,
 		BlockRoots:                 make([][]byte, 128),
 		Slashings:                  slashing,
@@ -489,7 +488,7 @@ func BenchmarkProcessBlk_65536Validators_FullBlock(b *testing.B) {
 		randaoMixes[i] = params.BeaconConfig().ZeroHash[:]
 	}
 
-	base := &statepb.BeaconState{
+	base := &ethpb.BeaconState{
 		Slot:              20,
 		LatestBlockHeader: &ethpb.BeaconBlockHeader{},
 		BlockRoots:        make([][]byte, 254),
@@ -500,7 +499,7 @@ func BenchmarkProcessBlk_65536Validators_FullBlock(b *testing.B) {
 		CurrentJustifiedCheckpoint: &ethpb.Checkpoint{
 			Root: []byte("hello-world"),
 		},
-		Fork: &statepb.Fork{
+		Fork: &ethpb.Fork{
 			PreviousVersion: []byte{0, 0, 0, 0},
 			CurrentVersion:  []byte{0, 0, 0, 0},
 		},
@@ -567,7 +566,7 @@ func BenchmarkProcessBlk_65536Validators_FullBlock(b *testing.B) {
 	binary.LittleEndian.PutUint64(buf, 0)
 	domain, err := helpers.Domain(s.Fork(), 0, params.BeaconConfig().DomainRandao, s.GenesisValidatorRoot())
 	require.NoError(b, err)
-	ctr := &statepb.SigningData{
+	ctr := &ethpb.SigningData{
 		ObjectRoot: buf,
 		Domain:     domain,
 	}
@@ -730,7 +729,7 @@ func TestCanProcessEpoch_TrueOnEpochs(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		b := &statepb.BeaconState{Slot: tt.slot}
+		b := &ethpb.BeaconState{Slot: tt.slot}
 		s, err := v1.InitializeFromProto(b)
 		require.NoError(t, err)
 		assert.Equal(t, tt.canProcessEpoch, core.CanProcessEpoch(s), "CanProcessEpoch(%d)", tt.slot)
@@ -797,7 +796,7 @@ func TestProcessBlock_OverMaxVoluntaryExits(t *testing.T) {
 }
 
 func TestProcessBlock_IncorrectDeposits(t *testing.T) {
-	base := &statepb.BeaconState{
+	base := &ethpb.BeaconState{
 		Eth1Data:         &ethpb.Eth1Data{DepositCount: 100},
 		Eth1DepositIndex: 98,
 	}
@@ -818,7 +817,7 @@ func TestProcessBlock_IncorrectDeposits(t *testing.T) {
 
 func TestProcessSlots_SameSlotAsParentState(t *testing.T) {
 	slot := types.Slot(2)
-	parentState, err := v1.InitializeFromProto(&statepb.BeaconState{Slot: slot})
+	parentState, err := v1.InitializeFromProto(&ethpb.BeaconState{Slot: slot})
 	require.NoError(t, err)
 
 	_, err = core.ProcessSlots(context.Background(), parentState, slot)
@@ -827,7 +826,7 @@ func TestProcessSlots_SameSlotAsParentState(t *testing.T) {
 
 func TestProcessSlots_LowerSlotAsParentState(t *testing.T) {
 	slot := types.Slot(2)
-	parentState, err := v1.InitializeFromProto(&statepb.BeaconState{Slot: slot})
+	parentState, err := v1.InitializeFromProto(&ethpb.BeaconState{Slot: slot})
 	require.NoError(t, err)
 
 	_, err = core.ProcessSlots(context.Background(), parentState, slot-1)

beacon-chain/core/validators/validator_test.go

@@ -7,7 +7,6 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
@@ -41,7 +40,7 @@ func TestHasVoted_OK(t *testing.T) {
 
 func TestInitiateValidatorExit_AlreadyExited(t *testing.T) {
 	exitEpoch := types.Epoch(199)
-	base := &statepb.BeaconState{Validators: []*ethpb.Validator{{
+	base := &ethpb.BeaconState{Validators: []*ethpb.Validator{{
 		ExitEpoch: exitEpoch},
 	}}
 	state, err := v1.InitializeFromProto(base)
@@ -56,7 +55,7 @@ func TestInitiateValidatorExit_AlreadyExited(t *testing.T) {
 func TestInitiateValidatorExit_ProperExit(t *testing.T) {
 	exitedEpoch := types.Epoch(100)
 	idx := types.ValidatorIndex(3)
-	base := &statepb.BeaconState{Validators: []*ethpb.Validator{
+	base := &ethpb.BeaconState{Validators: []*ethpb.Validator{
 		{ExitEpoch: exitedEpoch},
 		{ExitEpoch: exitedEpoch + 1},
 		{ExitEpoch: exitedEpoch + 2},
@@ -74,7 +73,7 @@ func TestInitiateValidatorExit_ProperExit(t *testing.T) {
 func TestInitiateValidatorExit_ChurnOverflow(t *testing.T) {
 	exitedEpoch := types.Epoch(100)
 	idx := types.ValidatorIndex(4)
-	base := &statepb.BeaconState{Validators: []*ethpb.Validator{
+	base := &ethpb.BeaconState{Validators: []*ethpb.Validator{
 		{ExitEpoch: exitedEpoch + 2},
 		{ExitEpoch: exitedEpoch + 2},
 		{ExitEpoch: exitedEpoch + 2},
@@ -110,7 +109,7 @@ func TestSlashValidator_OK(t *testing.T) {
 		balances = append(balances, params.BeaconConfig().MaxEffectiveBalance)
 	}
 
-	base := &statepb.BeaconState{
+	base := &ethpb.BeaconState{
 		Validators:  registry,
 		Slashings:   make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector),
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -153,11 +152,11 @@ func TestSlashValidator_OK(t *testing.T) {
 
 func TestActivatedValidatorIndices(t *testing.T) {
 	tests := []struct {
-		state  *statepb.BeaconState
+		state  *ethpb.BeaconState
 		wanted []types.ValidatorIndex
 	}{
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						ActivationEpoch: 0,
@@ -179,7 +178,7 @@ func TestActivatedValidatorIndices(t *testing.T) {
 			wanted: []types.ValidatorIndex{0, 1, 3},
 		},
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						ActivationEpoch: helpers.ActivationExitEpoch(10),
@@ -189,7 +188,7 @@ func TestActivatedValidatorIndices(t *testing.T) {
 			wanted: []types.ValidatorIndex{},
 		},
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						ActivationEpoch: 0,
@@ -210,11 +209,11 @@ func TestActivatedValidatorIndices(t *testing.T) {
 
 func TestSlashedValidatorIndices(t *testing.T) {
 	tests := []struct {
-		state  *statepb.BeaconState
+		state  *ethpb.BeaconState
 		wanted []types.ValidatorIndex
 	}{
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						WithdrawableEpoch: params.BeaconConfig().EpochsPerSlashingsVector,
@@ -233,7 +232,7 @@ func TestSlashedValidatorIndices(t *testing.T) {
 			wanted: []types.ValidatorIndex{0, 2},
 		},
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						WithdrawableEpoch: params.BeaconConfig().EpochsPerSlashingsVector,
@@ -243,7 +242,7 @@ func TestSlashedValidatorIndices(t *testing.T) {
 			wanted: []types.ValidatorIndex{},
 		},
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						WithdrawableEpoch: params.BeaconConfig().EpochsPerSlashingsVector,
@@ -264,11 +263,11 @@ func TestSlashedValidatorIndices(t *testing.T) {
 
 func TestExitedValidatorIndices(t *testing.T) {
 	tests := []struct {
-		state  *statepb.BeaconState
+		state  *ethpb.BeaconState
 		wanted []types.ValidatorIndex
 	}{
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
@@ -290,7 +289,7 @@ func TestExitedValidatorIndices(t *testing.T) {
 			wanted: []types.ValidatorIndex{0, 2},
 		},
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
@@ -302,7 +301,7 @@ func TestExitedValidatorIndices(t *testing.T) {
 			wanted: []types.ValidatorIndex{},
 		},
 		{
-			state: &statepb.BeaconState{
+			state: &ethpb.BeaconState{
 				Validators: []*ethpb.Validator{
 					{
 						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,

beacon-chain/db/kv/BUILD.bazel

@@ -3,6 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
+        "altair.go",
         "archived_point.go",
         "backup.go",
         "blocks.go",
@@ -40,6 +41,7 @@ go_library(
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/genesis:go_default_library",
         "//beacon-chain/state/v1:go_default_library",
+        "//beacon-chain/state/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/block:go_default_library",
         "//proto/prysm/v1alpha1/wrapper:go_default_library",
@@ -50,6 +52,7 @@ go_library(
         "//shared/progressutil:go_default_library",
         "//shared/sliceutil:go_default_library",
         "//shared/traceutil:go_default_library",
+        "//shared/version:go_default_library",
         "@com_github_dgraph_io_ristretto//:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ferranbt_fastssz//:go_default_library",
@@ -71,6 +74,7 @@ go_test(
     srcs = [
         "archived_point_test.go",
         "backup_test.go",
+        "block_altair_test.go",
         "blocks_test.go",
         "checkpoint_test.go",
         "deposit_contract_test.go",

beacon-chain/db/kv/altair.go

@@ -0,0 +1,11 @@
+package kv
+
+import "bytes"
+
+// In order for an encoding to be Altair compatible, it must be prefixed with altair key.
+func hasAltairKey(enc []byte) bool {
+	if len(altairKey) >= len(enc) {
+		return false
+	}
+	return bytes.Equal(enc[:len(altairKey)], altairKey)
+}

beacon-chain/db/kv/block_altair_test.go

@@ -0,0 +1,534 @@
+package kv
+
+import (
+	"context"
+	"sort"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
+	v2 "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
+	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"google.golang.org/protobuf/proto"
+)
+
+func TestStore_SaveAltairBlock_NoDuplicates(t *testing.T) {
+	BlockCacheSize = 1
+	db := setupDB(t)
+	slot := types.Slot(20)
+	ctx := context.Background()
+	// First we save a previous block to ensure the cache max size is reached.
+	prevBlock := testutil.NewBeaconBlockAltair()
+	prevBlock.Block.Slot = slot - 1
+	prevBlock.Block.ParentRoot = bytesutil.PadTo([]byte{1, 2, 3}, 32)
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(prevBlock)
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(ctx, wsb))
+
+	block := testutil.NewBeaconBlockAltair()
+	block.Block.Slot = slot
+	block.Block.ParentRoot = bytesutil.PadTo([]byte{1, 2, 3}, 32)
+	// Even with a full cache, saving new blocks should not cause
+	// duplicated blocks in the DB.
+	for i := 0; i < 100; i++ {
+		wsb, err = wrapper.WrappedAltairSignedBeaconBlock(block)
+		require.NoError(t, err)
+		require.NoError(t, db.SaveBlock(ctx, wsb))
+	}
+	f := filters.NewFilter().SetStartSlot(slot).SetEndSlot(slot)
+	retrieved, _, err := db.Blocks(ctx, f)
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(retrieved))
+	// We reset the block cache size.
+	BlockCacheSize = 256
+}
+
+func TestStore_AltairBlocksCRUD(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+
+	block := testutil.NewBeaconBlockAltair()
+	block.Block.Slot = 20
+	block.Block.ParentRoot = bytesutil.PadTo([]byte{1, 2, 3}, 32)
+
+	blockRoot, err := block.Block.HashTreeRoot()
+	require.NoError(t, err)
+	retrievedBlock, err := db.Block(ctx, blockRoot)
+	require.NoError(t, err)
+	assert.DeepEqual(t, nil, retrievedBlock, "Expected nil block")
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(ctx, wsb))
+	assert.Equal(t, true, db.HasBlock(ctx, blockRoot), "Expected block to exist in the db")
+	retrievedBlock, err = db.Block(ctx, blockRoot)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(block, retrievedBlock.Proto()), "Wanted: %v, received: %v", block, retrievedBlock)
+	require.NoError(t, db.deleteBlock(ctx, blockRoot))
+	assert.Equal(t, false, db.HasBlock(ctx, blockRoot), "Expected block to have been deleted from the db")
+}
+
+func TestStore_AltairBlocksBatchDelete(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+	numBlocks := 10
+	totalBlocks := make([]block.SignedBeaconBlock, numBlocks)
+	blockRoots := make([][32]byte, 0)
+	oddBlocks := make([]block.SignedBeaconBlock, 0)
+	for i := 0; i < len(totalBlocks); i++ {
+		b := testutil.NewBeaconBlockAltair()
+		b.Block.Slot = types.Slot(i)
+		b.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		wb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		totalBlocks[i] = wb
+		if i%2 == 0 {
+			r, err := totalBlocks[i].Block().HashTreeRoot()
+			require.NoError(t, err)
+			blockRoots = append(blockRoots, r)
+		} else {
+			oddBlocks = append(oddBlocks, totalBlocks[i])
+		}
+	}
+	require.NoError(t, db.SaveBlocks(ctx, totalBlocks))
+	retrieved, _, err := db.Blocks(ctx, filters.NewFilter().SetParentRoot(bytesutil.PadTo([]byte("parent"), 32)))
+	require.NoError(t, err)
+	assert.Equal(t, numBlocks, len(retrieved), "Unexpected number of blocks received")
+	// We delete all even indexed blocks.
+	require.NoError(t, db.deleteBlocks(ctx, blockRoots))
+	// When we retrieve the data, only the odd indexed blocks should remain.
+	retrieved, _, err = db.Blocks(ctx, filters.NewFilter().SetParentRoot(bytesutil.PadTo([]byte("parent"), 32)))
+	require.NoError(t, err)
+	sort.Slice(retrieved, func(i, j int) bool {
+		return retrieved[i].Block().Slot() < retrieved[j].Block().Slot()
+	})
+	for i, block := range retrieved {
+		assert.Equal(t, true, proto.Equal(block.Proto(), oddBlocks[i].Proto()), "Wanted: %v, received: %v", block, oddBlocks[i])
+	}
+}
+
+func TestStore_AltairBlocksHandleZeroCase(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+	numBlocks := 10
+	totalBlocks := make([]block.SignedBeaconBlock, numBlocks)
+	for i := 0; i < len(totalBlocks); i++ {
+		b := testutil.NewBeaconBlockAltair()
+		b.Block.Slot = types.Slot(i)
+		b.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		wb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		totalBlocks[i] = wb
+		_, err = totalBlocks[i].Block().HashTreeRoot()
+		require.NoError(t, err)
+	}
+	require.NoError(t, db.SaveBlocks(ctx, totalBlocks))
+	zeroFilter := filters.NewFilter().SetStartSlot(0).SetEndSlot(0)
+	retrieved, _, err := db.Blocks(ctx, zeroFilter)
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(retrieved), "Unexpected number of blocks received, expected one")
+}
+
+func TestStore_AltairBlocksHandleInvalidEndSlot(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+	numBlocks := 10
+	totalBlocks := make([]block.SignedBeaconBlock, numBlocks)
+	// Save blocks from slot 1 onwards.
+	for i := 0; i < len(totalBlocks); i++ {
+		b := testutil.NewBeaconBlockAltair()
+		b.Block.Slot = types.Slot(i) + 1
+		b.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		wb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		totalBlocks[i] = wb
+		_, err = totalBlocks[i].Block().HashTreeRoot()
+		require.NoError(t, err)
+	}
+	require.NoError(t, db.SaveBlocks(ctx, totalBlocks))
+	badFilter := filters.NewFilter().SetStartSlot(5).SetEndSlot(1)
+	_, _, err := db.Blocks(ctx, badFilter)
+	require.ErrorContains(t, errInvalidSlotRange.Error(), err)
+
+	goodFilter := filters.NewFilter().SetStartSlot(0).SetEndSlot(1)
+	requested, _, err := db.Blocks(ctx, goodFilter)
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(requested), "Unexpected number of blocks received, only expected two")
+}
+
+func TestStore_AltairBlocksCRUD_NoCache(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+	block := testutil.NewBeaconBlockAltair()
+	block.Block.Slot = 20
+	block.Block.ParentRoot = bytesutil.PadTo([]byte{1, 2, 3}, 32)
+	blockRoot, err := block.Block.HashTreeRoot()
+	require.NoError(t, err)
+	retrievedBlock, err := db.Block(ctx, blockRoot)
+	require.NoError(t, err)
+	require.DeepEqual(t, nil, retrievedBlock, "Expected nil block")
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(block)
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(ctx, wsb))
+	db.blockCache.Del(string(blockRoot[:]))
+	assert.Equal(t, true, db.HasBlock(ctx, blockRoot), "Expected block to exist in the db")
+	retrievedBlock, err = db.Block(ctx, blockRoot)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(block, retrievedBlock.Proto()), "Wanted: %v, received: %v", block, retrievedBlock)
+	require.NoError(t, db.deleteBlock(ctx, blockRoot))
+	assert.Equal(t, false, db.HasBlock(ctx, blockRoot), "Expected block to have been deleted from the db")
+}
+
+func TestStore_AltairBlocks_FiltersCorrectly(t *testing.T) {
+	db := setupDB(t)
+	b4 := testutil.NewBeaconBlockAltair()
+	b4.Block.Slot = 4
+	b4.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+	b5 := testutil.NewBeaconBlockAltair()
+	b5.Block.Slot = 5
+	b5.Block.ParentRoot = bytesutil.PadTo([]byte("parent2"), 32)
+	b6 := testutil.NewBeaconBlockAltair()
+	b6.Block.Slot = 6
+	b6.Block.ParentRoot = bytesutil.PadTo([]byte("parent2"), 32)
+	b7 := testutil.NewBeaconBlockAltair()
+	b7.Block.Slot = 7
+	b7.Block.ParentRoot = bytesutil.PadTo([]byte("parent3"), 32)
+	b8 := testutil.NewBeaconBlockAltair()
+	b8.Block.Slot = 8
+	b8.Block.ParentRoot = bytesutil.PadTo([]byte("parent4"), 32)
+	blocks := make([]block.SignedBeaconBlock, 0)
+	for _, b := range []*v2.SignedBeaconBlockAltair{b4, b5, b6, b7, b8} {
+		blk, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		blocks = append(blocks, blk)
+	}
+	ctx := context.Background()
+	require.NoError(t, db.SaveBlocks(ctx, blocks))
+
+	tests := []struct {
+		filter            *filters.QueryFilter
+		expectedNumBlocks int
+	}{
+		{
+			filter:            filters.NewFilter().SetParentRoot(bytesutil.PadTo([]byte("parent2"), 32)),
+			expectedNumBlocks: 2,
+		},
+		{
+			// No block meets the criteria below.
+			filter:            filters.NewFilter().SetParentRoot(bytesutil.PadTo([]byte{3, 4, 5}, 32)),
+			expectedNumBlocks: 0,
+		},
+		{
+			// Block slot range filter criteria.
+			filter:            filters.NewFilter().SetStartSlot(5).SetEndSlot(7),
+			expectedNumBlocks: 3,
+		},
+		{
+			filter:            filters.NewFilter().SetStartSlot(7).SetEndSlot(7),
+			expectedNumBlocks: 1,
+		},
+		{
+			filter:            filters.NewFilter().SetStartSlot(4).SetEndSlot(8),
+			expectedNumBlocks: 5,
+		},
+		{
+			filter:            filters.NewFilter().SetStartSlot(4).SetEndSlot(5),
+			expectedNumBlocks: 2,
+		},
+		{
+			filter:            filters.NewFilter().SetStartSlot(5).SetEndSlot(9),
+			expectedNumBlocks: 4,
+		},
+		{
+			filter:            filters.NewFilter().SetEndSlot(7),
+			expectedNumBlocks: 4,
+		},
+		{
+			filter:            filters.NewFilter().SetEndSlot(8),
+			expectedNumBlocks: 5,
+		},
+		{
+			filter:            filters.NewFilter().SetStartSlot(5).SetEndSlot(10),
+			expectedNumBlocks: 4,
+		},
+		{
+			// Composite filter criteria.
+			filter: filters.NewFilter().
+				SetParentRoot(bytesutil.PadTo([]byte("parent2"), 32)).
+				SetStartSlot(6).
+				SetEndSlot(8),
+			expectedNumBlocks: 1,
+		},
+	}
+	for _, tt := range tests {
+		retrievedBlocks, _, err := db.Blocks(ctx, tt.filter)
+		require.NoError(t, err)
+		assert.Equal(t, tt.expectedNumBlocks, len(retrievedBlocks), "Unexpected number of blocks")
+	}
+}
+
+func TestStore_AltairBlocks_VerifyBlockRoots(t *testing.T) {
+	ctx := context.Background()
+	db := setupDB(t)
+	b1 := testutil.NewBeaconBlockAltair()
+	b1.Block.Slot = 1
+	r1, err := b1.Block.HashTreeRoot()
+	require.NoError(t, err)
+	b2 := testutil.NewBeaconBlockAltair()
+	b2.Block.Slot = 2
+	r2, err := b2.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	for _, b := range []*v2.SignedBeaconBlockAltair{b1, b2} {
+		wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		require.NoError(t, db.SaveBlock(ctx, wsb))
+	}
+
+	filter := filters.NewFilter().SetStartSlot(b1.Block.Slot).SetEndSlot(b2.Block.Slot)
+	roots, err := db.BlockRoots(ctx, filter)
+	require.NoError(t, err)
+
+	assert.DeepEqual(t, [][32]byte{r1, r2}, roots)
+}
+
+func TestStore_AltairBlocks_Retrieve_SlotRange(t *testing.T) {
+	db := setupDB(t)
+	totalBlocks := make([]block.SignedBeaconBlock, 500)
+	for i := 0; i < 500; i++ {
+		b := testutil.NewBeaconBlockAltair()
+		b.Block.Slot = types.Slot(i)
+		b.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		wb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		totalBlocks[i] = wb
+	}
+	ctx := context.Background()
+	require.NoError(t, db.SaveBlocks(ctx, totalBlocks))
+	retrieved, _, err := db.Blocks(ctx, filters.NewFilter().SetStartSlot(100).SetEndSlot(399))
+	require.NoError(t, err)
+	assert.Equal(t, 300, len(retrieved))
+}
+
+func TestStore_AltairBlocks_Retrieve_Epoch(t *testing.T) {
+	db := setupDB(t)
+	slots := params.BeaconConfig().SlotsPerEpoch.Mul(7)
+	totalBlocks := make([]block.SignedBeaconBlock, slots)
+	for i := types.Slot(0); i < slots; i++ {
+		b := testutil.NewBeaconBlockAltair()
+		b.Block.Slot = i
+		b.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		wb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		totalBlocks[i] = wb
+	}
+	ctx := context.Background()
+	require.NoError(t, db.SaveBlocks(ctx, totalBlocks))
+	retrieved, _, err := db.Blocks(ctx, filters.NewFilter().SetStartEpoch(5).SetEndEpoch(6))
+	require.NoError(t, err)
+	want := params.BeaconConfig().SlotsPerEpoch.Mul(2)
+	assert.Equal(t, uint64(want), uint64(len(retrieved)))
+	retrieved, _, err = db.Blocks(ctx, filters.NewFilter().SetStartEpoch(0).SetEndEpoch(0))
+	require.NoError(t, err)
+	want = params.BeaconConfig().SlotsPerEpoch
+	assert.Equal(t, uint64(want), uint64(len(retrieved)))
+}
+
+func TestStore_AltairBlocks_Retrieve_SlotRangeWithStep(t *testing.T) {
+	db := setupDB(t)
+	totalBlocks := make([]block.SignedBeaconBlock, 500)
+	for i := 0; i < 500; i++ {
+		b := testutil.NewBeaconBlockAltair()
+		b.Block.Slot = types.Slot(i)
+		b.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		wb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		totalBlocks[i] = wb
+	}
+	const step = 2
+	ctx := context.Background()
+	require.NoError(t, db.SaveBlocks(ctx, totalBlocks))
+	retrieved, _, err := db.Blocks(ctx, filters.NewFilter().SetStartSlot(100).SetEndSlot(399).SetSlotStep(step))
+	require.NoError(t, err)
+	assert.Equal(t, 150, len(retrieved))
+	for _, b := range retrieved {
+		assert.Equal(t, types.Slot(0), (b.Block().Slot()-100)%step, "Unexpect block slot %d", b.Block().Slot())
+	}
+}
+
+func TestStore_SaveAltairBlock_CanGetHighestAt(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+
+	block1 := testutil.NewBeaconBlockAltair()
+	block1.Block.Slot = 1
+	block2 := testutil.NewBeaconBlockAltair()
+	block2.Block.Slot = 10
+	block3 := testutil.NewBeaconBlockAltair()
+	block3.Block.Slot = 100
+
+	for _, b := range []*v2.SignedBeaconBlockAltair{block1, block2, block3} {
+		wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		require.NoError(t, db.SaveBlock(ctx, wsb))
+	}
+
+	highestAt, err := db.HighestSlotBlocksBelow(ctx, 2)
+	require.NoError(t, err)
+	assert.Equal(t, false, len(highestAt) <= 0, "Got empty highest at slice")
+	assert.Equal(t, true, proto.Equal(block1, highestAt[0].Proto()), "Wanted: %v, received: %v", block1, highestAt[0])
+	highestAt, err = db.HighestSlotBlocksBelow(ctx, 11)
+	require.NoError(t, err)
+	assert.Equal(t, false, len(highestAt) <= 0, "Got empty highest at slice")
+	assert.Equal(t, true, proto.Equal(block2, highestAt[0].Proto()), "Wanted: %v, received: %v", block2, highestAt[0])
+	highestAt, err = db.HighestSlotBlocksBelow(ctx, 101)
+	require.NoError(t, err)
+	assert.Equal(t, false, len(highestAt) <= 0, "Got empty highest at slice")
+	assert.Equal(t, true, proto.Equal(block3, highestAt[0].Proto()), "Wanted: %v, received: %v", block3, highestAt[0])
+
+	r3, err := block3.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, db.deleteBlock(ctx, r3))
+
+	highestAt, err = db.HighestSlotBlocksBelow(ctx, 101)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(block2, highestAt[0].Proto()), "Wanted: %v, received: %v", block2, highestAt[0])
+}
+
+func TestStore_GenesisAltairBlock_CanGetHighestAt(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+
+	genesisBlock := testutil.NewBeaconBlockAltair()
+	genesisRoot, err := genesisBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, db.SaveGenesisBlockRoot(ctx, genesisRoot))
+	wsb, err := wrapper.WrappedAltairSignedBeaconBlock(genesisBlock)
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(ctx, wsb))
+	block1 := testutil.NewBeaconBlockAltair()
+	block1.Block.Slot = 1
+	wsb, err = wrapper.WrappedAltairSignedBeaconBlock(block1)
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(ctx, wsb))
+
+	highestAt, err := db.HighestSlotBlocksBelow(ctx, 2)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(block1, highestAt[0].Proto()), "Wanted: %v, received: %v", block1, highestAt[0])
+	highestAt, err = db.HighestSlotBlocksBelow(ctx, 1)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(genesisBlock, highestAt[0].Proto()), "Wanted: %v, received: %v", genesisBlock, highestAt[0])
+	highestAt, err = db.HighestSlotBlocksBelow(ctx, 0)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(genesisBlock, highestAt[0].Proto()), "Wanted: %v, received: %v", genesisBlock, highestAt[0])
+}
+
+func TestStore_SaveAltairBlocks_HasCachedBlocks(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+
+	var err error
+	b := make([]block.SignedBeaconBlock, 500)
+	for i := 0; i < 500; i++ {
+		blk := testutil.NewBeaconBlockAltair()
+		blk.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		blk.Block.Slot = types.Slot(i)
+		b[i], err = wrapper.WrappedAltairSignedBeaconBlock(blk)
+		require.NoError(t, err)
+	}
+
+	require.NoError(t, db.SaveBlock(ctx, b[0]))
+	require.NoError(t, db.SaveBlocks(ctx, b))
+	f := filters.NewFilter().SetStartSlot(0).SetEndSlot(500)
+
+	blks, _, err := db.Blocks(ctx, f)
+	require.NoError(t, err)
+	assert.Equal(t, 500, len(blks), "Did not get wanted blocks")
+}
+
+func TestStore_SaveAltairBlocks_HasRootsMatched(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+
+	var err error
+	b := make([]block.SignedBeaconBlock, 500)
+	for i := 0; i < 500; i++ {
+		blk := testutil.NewBeaconBlockAltair()
+		blk.Block.ParentRoot = bytesutil.PadTo([]byte("parent"), 32)
+		blk.Block.Slot = types.Slot(i)
+		b[i], err = wrapper.WrappedAltairSignedBeaconBlock(blk)
+		require.NoError(t, err)
+	}
+
+	require.NoError(t, db.SaveBlocks(ctx, b))
+	f := filters.NewFilter().SetStartSlot(0).SetEndSlot(500)
+
+	blks, roots, err := db.Blocks(ctx, f)
+	require.NoError(t, err)
+	assert.Equal(t, 500, len(blks), "Did not get wanted blocks")
+
+	for i, blk := range blks {
+		rt, err := blk.Block().HashTreeRoot()
+		require.NoError(t, err)
+		assert.Equal(t, roots[i], rt, "mismatch of block roots")
+	}
+}
+
+func TestStore_AltairBlocksBySlot_BlockRootsBySlot(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+
+	b1 := testutil.NewBeaconBlockAltair()
+	b1.Block.Slot = 20
+	b2 := testutil.NewBeaconBlockAltair()
+	b2.Block.Slot = 100
+	b2.Block.ParentRoot = bytesutil.PadTo([]byte("parent1"), 32)
+	b3 := testutil.NewBeaconBlockAltair()
+	b3.Block.Slot = 100
+	b3.Block.ParentRoot = bytesutil.PadTo([]byte("parent2"), 32)
+
+	for _, b := range []*v2.SignedBeaconBlockAltair{b1, b2, b3} {
+		wsb, err := wrapper.WrappedAltairSignedBeaconBlock(b)
+		require.NoError(t, err)
+		require.NoError(t, db.SaveBlock(ctx, wsb))
+	}
+
+	r1, err := b1.Block.HashTreeRoot()
+	require.NoError(t, err)
+	r2, err := b2.Block.HashTreeRoot()
+	require.NoError(t, err)
+	r3, err := b3.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	hasBlocks, retrievedBlocks, err := db.BlocksBySlot(ctx, 1)
+	require.NoError(t, err)
+	assert.Equal(t, 0, len(retrievedBlocks), "Unexpected number of blocks received, expected none")
+	assert.Equal(t, false, hasBlocks, "Expected no blocks")
+	hasBlocks, retrievedBlocks, err = db.BlocksBySlot(ctx, 20)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(b1, retrievedBlocks[0].Proto()), "Wanted: %v, received: %v", b1, retrievedBlocks[0])
+	assert.Equal(t, true, hasBlocks, "Expected to have blocks")
+	hasBlocks, retrievedBlocks, err = db.BlocksBySlot(ctx, 100)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(b2, retrievedBlocks[0].Proto()), "Wanted: %v, received: %v", b2, retrievedBlocks[0])
+	assert.Equal(t, true, proto.Equal(b3, retrievedBlocks[1].Proto()), "Wanted: %v, received: %v", b3, retrievedBlocks[1])
+	assert.Equal(t, true, hasBlocks, "Expected to have blocks")
+
+	hasBlockRoots, retrievedBlockRoots, err := db.BlockRootsBySlot(ctx, 1)
+	require.NoError(t, err)
+	assert.DeepEqual(t, [][32]byte{}, retrievedBlockRoots)
+	assert.Equal(t, false, hasBlockRoots, "Expected no block roots")
+	hasBlockRoots, retrievedBlockRoots, err = db.BlockRootsBySlot(ctx, 20)
+	require.NoError(t, err)
+	assert.DeepEqual(t, [][32]byte{r1}, retrievedBlockRoots)
+	assert.Equal(t, true, hasBlockRoots, "Expected no block roots")
+	hasBlockRoots, retrievedBlockRoots, err = db.BlockRootsBySlot(ctx, 100)
+	require.NoError(t, err)
+	assert.DeepEqual(t, [][32]byte{r2, r3}, retrievedBlockRoots)
+	assert.Equal(t, true, hasBlockRoots, "Expected no block roots")
+}

beacon-chain/db/kv/blocks.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/golang/snappy"
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
@@ -15,6 +16,7 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/sliceutil"
+	"github.com/prysmaticlabs/prysm/shared/version"
 	bolt "go.etcd.io/bbolt"
 	"go.opencensus.io/trace"
 )
@@ -30,24 +32,25 @@ func (s *Store) Block(ctx context.Context, blockRoot [32]byte) (block.SignedBeac
 	if v, ok := s.blockCache.Get(string(blockRoot[:])); v != nil && ok {
 		return v.(block.SignedBeaconBlock), nil
 	}
-	var block *ethpb.SignedBeaconBlock
+	var block block.SignedBeaconBlock
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(blocksBucket)
 		enc := bkt.Get(blockRoot[:])
 		if enc == nil {
 			return nil
 		}
-		block = &ethpb.SignedBeaconBlock{}
-		return decode(ctx, enc, block)
+		var err error
+		block, err = unmarshalBlock(ctx, enc)
+		return err
 	})
-	return wrapper.WrappedPhase0SignedBeaconBlock(block), err
+	return block, err
 }
 
 // HeadBlock returns the latest canonical block in the Ethereum Beacon Chain.
 func (s *Store) HeadBlock(ctx context.Context) (block.SignedBeaconBlock, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.HeadBlock")
 	defer span.End()
-	var headBlock *ethpb.SignedBeaconBlock
+	var headBlock block.SignedBeaconBlock
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(blocksBucket)
 		headRoot := bkt.Get(headBlockRootKey)
@@ -58,10 +61,11 @@ func (s *Store) HeadBlock(ctx context.Context) (block.SignedBeaconBlock, error)
 		if enc == nil {
 			return nil
 		}
-		headBlock = &ethpb.SignedBeaconBlock{}
-		return decode(ctx, enc, headBlock)
+		var err error
+		headBlock, err = unmarshalBlock(ctx, enc)
+		return err
 	})
-	return wrapper.WrappedPhase0SignedBeaconBlock(headBlock), err
+	return headBlock, err
 }
 
 // Blocks retrieves a list of beacon blocks and its respective roots by filter criteria.
@@ -81,11 +85,11 @@ func (s *Store) Blocks(ctx context.Context, f *filters.QueryFilter) ([]block.Sig
 
 		for i := 0; i < len(keys); i++ {
 			encoded := bkt.Get(keys[i])
-			block := &ethpb.SignedBeaconBlock{}
-			if err := decode(ctx, encoded, block); err != nil {
+			block, err := unmarshalBlock(ctx, encoded)
+			if err != nil {
 				return err
 			}
-			blocks = append(blocks, wrapper.WrappedPhase0SignedBeaconBlock(block))
+			blocks = append(blocks, block)
 			blockRoots = append(blockRoots, bytesutil.ToBytes32(keys[i]))
 		}
 		return nil
@@ -153,11 +157,11 @@ func (s *Store) BlocksBySlot(ctx context.Context, slot types.Slot) (bool, []bloc
 
 		for i := 0; i < len(keys); i++ {
 			encoded := bkt.Get(keys[i])
-			block := &ethpb.SignedBeaconBlock{}
-			if err := decode(ctx, encoded, block); err != nil {
+			block, err := unmarshalBlock(ctx, encoded)
+			if err != nil {
 				return err
 			}
-			blocks = append(blocks, wrapper.WrappedPhase0SignedBeaconBlock(block))
+			blocks = append(blocks, block)
 		}
 		return nil
 	})
@@ -196,11 +200,11 @@ func (s *Store) deleteBlock(ctx context.Context, blockRoot [32]byte) error {
 		if enc == nil {
 			return nil
 		}
-		block := &ethpb.SignedBeaconBlock{}
-		if err := decode(ctx, enc, block); err != nil {
+		block, err := unmarshalBlock(ctx, enc)
+		if err != nil {
 			return err
 		}
-		indicesByBucket := createBlockIndicesFromBlock(ctx, wrapper.WrappedPhase0BeaconBlock(block.Block))
+		indicesByBucket := createBlockIndicesFromBlock(ctx, block.Block())
 		if err := deleteValueForIndices(ctx, indicesByBucket, blockRoot[:], tx); err != nil {
 			return errors.Wrap(err, "could not delete root for DB indices")
 		}
@@ -221,11 +225,11 @@ func (s *Store) deleteBlocks(ctx context.Context, blockRoots [][32]byte) error {
 			if enc == nil {
 				return nil
 			}
-			block := &ethpb.SignedBeaconBlock{}
-			if err := decode(ctx, enc, block); err != nil {
+			block, err := unmarshalBlock(ctx, enc)
+			if err != nil {
 				return err
 			}
-			indicesByBucket := createBlockIndicesFromBlock(ctx, wrapper.WrappedPhase0BeaconBlock(block.Block))
+			indicesByBucket := createBlockIndicesFromBlock(ctx, block.Block())
 			if err := deleteValueForIndices(ctx, indicesByBucket, blockRoot[:], tx); err != nil {
 				return errors.Wrap(err, "could not delete root for DB indices")
 			}
@@ -269,7 +273,7 @@ func (s *Store) SaveBlocks(ctx context.Context, blocks []block.SignedBeaconBlock
 			if existingBlock := bkt.Get(blockRoot[:]); existingBlock != nil {
 				continue
 			}
-			enc, err := encode(ctx, block.Proto())
+			enc, err := marshalBlock(ctx, block)
 			if err != nil {
 				return err
 			}
@@ -307,7 +311,7 @@ func (s *Store) SaveHeadBlockRoot(ctx context.Context, blockRoot [32]byte) error
 func (s *Store) GenesisBlock(ctx context.Context) (block.SignedBeaconBlock, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.GenesisBlock")
 	defer span.End()
-	var block *ethpb.SignedBeaconBlock
+	var block block.SignedBeaconBlock
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(blocksBucket)
 		root := bkt.Get(genesisBlockRootKey)
@@ -315,10 +319,11 @@ func (s *Store) GenesisBlock(ctx context.Context) (block.SignedBeaconBlock, erro
 		if enc == nil {
 			return nil
 		}
-		block = &ethpb.SignedBeaconBlock{}
-		return decode(ctx, enc, block)
+		var err error
+		block, err = unmarshalBlock(ctx, enc)
+		return err
 	})
-	return wrapper.WrappedPhase0SignedBeaconBlock(block), err
+	return block, err
 }
 
 // SaveGenesisBlockRoot to the db.
@@ -579,3 +584,46 @@ func createBlockIndicesFromFilters(ctx context.Context, f *filters.QueryFilter)
 	}
 	return indicesByBucket, nil
 }
+
+// unmarshal block from marshaled proto beacon block bytes to versioned beacon block struct type.
+func unmarshalBlock(ctx context.Context, enc []byte) (block.SignedBeaconBlock, error) {
+	var err error
+	enc, err = snappy.Decode(nil, enc)
+	if err != nil {
+		return nil, err
+	}
+	switch {
+	case hasAltairKey(enc):
+		// Marshal block bytes to altair beacon block.
+		rawBlock := &ethpb.SignedBeaconBlockAltair{}
+		err := rawBlock.UnmarshalSSZ(enc[len(altairKey):])
+		if err != nil {
+			return nil, err
+		}
+		return wrapper.WrappedAltairSignedBeaconBlock(rawBlock)
+	default:
+		// Marshal block bytes to phase 0 beacon block.
+		rawBlock := &ethpb.SignedBeaconBlock{}
+		err = rawBlock.UnmarshalSSZ(enc)
+		if err != nil {
+			return nil, err
+		}
+		return wrapper.WrappedPhase0SignedBeaconBlock(rawBlock), nil
+	}
+}
+
+// marshal versioned beacon block from struct type down to bytes.
+func marshalBlock(ctx context.Context, blk block.SignedBeaconBlock) ([]byte, error) {
+	obj, err := blk.MarshalSSZ()
+	if err != nil {
+		return nil, err
+	}
+	switch blk.Version() {
+	case version.Altair:
+		return snappy.Encode(nil, append(altairKey, obj...)), nil
+	case version.Phase0:
+		return snappy.Encode(nil, obj), nil
+	default:
+		return nil, errors.New("Unknown block version")
+	}
+}

beacon-chain/db/kv/blocks_test.go

@@ -7,7 +7,6 @@ import (
 
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
@@ -57,7 +56,7 @@ func TestStore_BlocksCRUD(t *testing.T) {
 	require.NoError(t, err)
 	retrievedBlock, err := db.Block(ctx, blockRoot)
 	require.NoError(t, err)
-	assert.DeepEqual(t, (*ethpb.SignedBeaconBlock)(nil), retrievedBlock.Proto(), "Expected nil block")
+	assert.DeepEqual(t, nil, retrievedBlock, "Expected nil block")
 	require.NoError(t, db.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(block)))
 	assert.Equal(t, true, db.HasBlock(ctx, blockRoot), "Expected block to exist in the db")
 	retrievedBlock, err = db.Block(ctx, blockRoot)
@@ -173,7 +172,7 @@ func TestStore_BlocksCRUD_NoCache(t *testing.T) {
 	require.NoError(t, err)
 	retrievedBlock, err := db.Block(ctx, blockRoot)
 	require.NoError(t, err)
-	require.DeepEqual(t, (*ethpb.SignedBeaconBlock)(nil), retrievedBlock.Proto(), "Expected nil block")
+	require.DeepEqual(t, nil, retrievedBlock, "Expected nil block")
 	require.NoError(t, db.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(block)))
 	db.blockCache.Del(string(blockRoot[:]))
 	assert.Equal(t, true, db.HasBlock(ctx, blockRoot), "Expected block to exist in the db")

beacon-chain/db/kv/schema.go

@@ -43,6 +43,9 @@ var (
 	justifiedCheckpointKey    = []byte("justified-checkpoint")
 	finalizedCheckpointKey    = []byte("finalized-checkpoint")
 	powchainDataKey           = []byte("powchain-data")
+	// Altair key used to identify object is altair compatible.
+	// Objects that are only compatible with altair should be prefixed with such key.
+	altairKey = []byte("altair")
 
 	// Deprecated: This index key was migrated in PR 6461. Do not use, except for migrations.
 	lastArchivedIndexKey = []byte("last-archived")

beacon-chain/db/kv/state.go

@@ -11,8 +11,8 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/genesis"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	v1alpha "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	v2 "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/featureconfig"
@@ -27,7 +27,6 @@ import (
 func (s *Store) State(ctx context.Context, blockRoot [32]byte) (state.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.State")
 	defer span.End()
-	var st *statepb.BeaconState
 	enc, err := s.stateBytes(ctx, blockRoot)
 	if err != nil {
 		return nil, err
@@ -36,18 +35,13 @@ func (s *Store) State(ctx context.Context, blockRoot [32]byte) (state.BeaconStat
 	if len(enc) == 0 {
 		return nil, nil
 	}
-
 	// get the validator entries of the state
 	valEntries, valErr := s.validatorEntries(ctx, blockRoot)
 	if valErr != nil {
 		return nil, valErr
 	}
 
-	st, err = s.createState(ctx, enc, valEntries)
-	if err != nil {
-		return nil, err
-	}
-	return v1.InitializeFromProtoUnsafe(st)
+	return s.unmarshalState(ctx, enc, valEntries)
 }
 
 // GenesisState returns the genesis state in beacon chain.
@@ -65,8 +59,8 @@ func (s *Store) GenesisState(ctx context.Context) (state.BeaconState, error) {
 		return cached, nil
 	}
 
-	var st *statepb.BeaconState
-	if err = s.db.View(func(tx *bolt.Tx) error {
+	var st state.BeaconState
+	err = s.db.View(func(tx *bolt.Tx) error {
 		// Retrieve genesis block's signing root from blocks bucket,
 		// to look up what the genesis state is.
 		bucket := tx.Bucket(blocksBucket)
@@ -77,7 +71,6 @@ func (s *Store) GenesisState(ctx context.Context) (state.BeaconState, error) {
 		if enc == nil {
 			return nil
 		}
-
 		// get the validator entries of the genesis state
 		valEntries, valErr := s.validatorEntries(ctx, bytesutil.ToBytes32(genesisBlockRoot))
 		if valErr != nil {
@@ -85,15 +78,16 @@ func (s *Store) GenesisState(ctx context.Context) (state.BeaconState, error) {
 		}
 
 		var crtErr error
-		st, crtErr = s.createState(ctx, enc, valEntries)
+		st, err = s.unmarshalState(ctx, enc, valEntries)
 		return crtErr
-	}); err != nil {
+	})
+	if err != nil {
 		return nil, err
 	}
-	if st == nil {
+	if st == nil || st.IsNil() {
 		return nil, nil
 	}
-	return v1.InitializeFromProtoUnsafe(st)
+	return st, nil
 }
 
 // SaveState stores a state to the db using block's signing root which was used to generate the state.
@@ -119,14 +113,11 @@ func (s *Store) SaveStates(ctx context.Context, states []state.ReadOnlyBeaconSta
 	}
 	multipleEncs := make([][]byte, len(states))
 	for i, st := range states {
-		pbState, err := v1.ProtobufBeaconState(st.InnerStateUnsafe())
-		if err != nil {
-			return err
-		}
-		multipleEncs[i], err = encode(ctx, pbState)
+		stateBytes, err := marshalState(ctx, st)
 		if err != nil {
 			return err
 		}
+		multipleEncs[i] = stateBytes
 	}
 
 	return s.db.Update(func(tx *bolt.Tx) error {
@@ -151,8 +142,8 @@ func (s *Store) SaveStatesEfficient(ctx context.Context, states []state.ReadOnly
 	if states == nil {
 		return errors.New("nil state")
 	}
-	validatorsEntries := make(map[string]*v1alpha.Validator) // It's a map to make sure that you store only new validator entries.
-	validatorKeys := make([][]byte, len(states))             // For every state, this stores a compressed list of validator keys.
+	validatorsEntries := make(map[string]*ethpb.Validator) // It's a map to make sure that you store only new validator entries.
+	validatorKeys := make([][]byte, len(states))           // For every state, this stores a compressed list of validator keys.
 	for i, st := range states {
 		pbState, err := v1.ProtobufBeaconState(st.InnerStateUnsafe())
 		if err != nil {
@@ -195,7 +186,7 @@ func (s *Store) SaveStatesEfficient(ctx context.Context, states []state.ReadOnly
 				return err
 			}
 			valEntries := pbState.Validators
-			pbState.Validators = make([]*v1alpha.Validator, 0)
+			pbState.Validators = make([]*ethpb.Validator, 0)
 			encodedState, err := encode(ctx, pbState)
 			if err != nil {
 				return err
@@ -270,9 +261,9 @@ func (s *Store) DeleteState(ctx context.Context, blockRoot [32]byte) error {
 
 		bkt = tx.Bucket(checkpointBucket)
 		enc := bkt.Get(finalizedCheckpointKey)
-		checkpoint := &v1alpha.Checkpoint{}
+		checkpoint := &ethpb.Checkpoint{}
 		if enc == nil {
-			checkpoint = &v1alpha.Checkpoint{Root: genesisBlockRoot}
+			checkpoint = &ethpb.Checkpoint{Root: genesisBlockRoot}
 		} else if err := decode(ctx, enc, checkpoint); err != nil {
 			return err
 		}
@@ -342,36 +333,86 @@ func (s *Store) DeleteStates(ctx context.Context, blockRoots [][32]byte) error {
 	return nil
 }
 
-// creates state from marshaled proto state bytes. Also add the validator entries retrieved
-// from the validator bucket and complete the state construction.
-func (s *Store) createState(ctx context.Context, enc []byte, validatorEntries []*v1alpha.Validator) (*statepb.BeaconState, error) {
-	protoState := &statepb.BeaconState{}
-	if err := decode(ctx, enc, protoState); err != nil {
-		return nil, errors.Wrap(err, "failed to unmarshal encoding")
-	}
-	ok, err := s.isStateValidatorMigrationOver()
+// unmarshal state from marshaled proto state bytes to versioned state struct type.
+func (s *Store) unmarshalState(ctx context.Context, enc []byte, validatorEntries []*ethpb.Validator) (state.BeaconState, error) {
+	var err error
+	enc, err = snappy.Decode(nil, enc)
 	if err != nil {
-		return protoState, err
+		return nil, err
 	}
-	if ok {
-		protoState.Validators = validatorEntries
+
+	switch {
+	case hasAltairKey(enc):
+		// Marshal state bytes to altair beacon state.
+		protoState := &ethpb.BeaconStateAltair{}
+		if err := protoState.UnmarshalSSZ(enc[len(altairKey):]); err != nil {
+			return nil, errors.Wrap(err, "failed to unmarshal encoding for altair")
+		}
+		ok, err := s.isStateValidatorMigrationOver()
+		if err != nil {
+			return nil, err
+		}
+		if ok {
+			protoState.Validators = validatorEntries
+		}
+		return v2.InitializeFromProtoUnsafe(protoState)
+	default:
+		// Marshal state bytes to phase 0 beacon state.
+		protoState := &ethpb.BeaconState{}
+		if err := protoState.UnmarshalSSZ(enc); err != nil {
+			return nil, errors.Wrap(err, "failed to unmarshal encoding")
+		}
+		ok, err := s.isStateValidatorMigrationOver()
+		if err != nil {
+			return nil, err
+		}
+		if ok {
+			protoState.Validators = validatorEntries
+		}
+		return v1.InitializeFromProtoUnsafe(protoState)
+	}
+}
+
+// marshal versioned state from struct type down to bytes.
+func marshalState(ctx context.Context, st state.ReadOnlyBeaconState) ([]byte, error) {
+	switch st.InnerStateUnsafe().(type) {
+	case *ethpb.BeaconState:
+		rState, ok := st.InnerStateUnsafe().(*ethpb.BeaconState)
+		if !ok {
+			return nil, errors.New("non valid inner state")
+		}
+		return encode(ctx, rState)
+	case *ethpb.BeaconStateAltair:
+		rState, ok := st.InnerStateUnsafe().(*ethpb.BeaconStateAltair)
+		if !ok {
+			return nil, errors.New("non valid inner state")
+		}
+		if rState == nil {
+			return nil, errors.New("nil state")
+		}
+		rawObj, err := rState.MarshalSSZ()
+		if err != nil {
+			return nil, err
+		}
+		return snappy.Encode(nil, append(altairKey, rawObj...)), nil
+	default:
+		return nil, errors.New("invalid inner state")
 	}
-	return protoState, nil
 }
 
 // Retrieve the validator entries for a given block root. These entries are stored in a
 // separate bucket to reduce state size.
-func (s *Store) validatorEntries(ctx context.Context, blockRoot [32]byte) ([]*v1alpha.Validator, error) {
+func (s *Store) validatorEntries(ctx context.Context, blockRoot [32]byte) ([]*ethpb.Validator, error) {
 	ok, err := s.isStateValidatorMigrationOver()
 	if err != nil {
 		return nil, err
 	}
 	if !ok {
-		return make([]*v1alpha.Validator, 0), nil
+		return make([]*ethpb.Validator, 0), nil
 	}
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.validatorEntries")
 	defer span.End()
-	var validatorEntries []*v1alpha.Validator
+	var validatorEntries []*ethpb.Validator
 	err = s.db.View(func(tx *bolt.Tx) error {
 		// get the validator keys from the index bucket
 		idxBkt := tx.Bucket(blockRootValidatorHashesBucket)
@@ -396,7 +437,7 @@ func (s *Store) validatorEntries(ctx context.Context, blockRoot [32]byte) ([]*v1
 			// get the entry bytes from the cache or from the DB.
 			v, ok := s.validatorEntryCache.Get(key)
 			if ok {
-				valEntry, vType := v.(*v1alpha.Validator)
+				valEntry, vType := v.(*ethpb.Validator)
 				if vType {
 					s.validatorEntryCache.Set(key, valEntry, int64(valEntry.SizeSSZ()))
 					validatorEntries = append(validatorEntries, valEntry)
@@ -411,7 +452,7 @@ func (s *Store) validatorEntries(ctx context.Context, blockRoot [32]byte) ([]*v1
 				if len(valEntryBytes) == 0 {
 					return errors.New("could not find validator entry")
 				}
-				encValEntry := &v1alpha.Validator{}
+				encValEntry := &ethpb.Validator{}
 				decodeErr := decode(ctx, valEntryBytes, encValEntry)
 				if decodeErr != nil {
 					return errors.Wrap(decodeErr, "failed to decode validator entry keys")
@@ -425,7 +466,7 @@ func (s *Store) validatorEntries(ctx context.Context, blockRoot [32]byte) ([]*v1
 	return validatorEntries, err
 }
 
-/// retrieves and assembles the state information from multiple buckets.
+// retrieves and assembles the state information from multiple buckets.
 func (s *Store) stateBytes(ctx context.Context, blockRoot [32]byte) ([]byte, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.stateBytes")
 	defer span.End()
@@ -468,16 +509,16 @@ func (s *Store) slotByBlockRoot(ctx context.Context, tx *bolt.Tx, blockRoot []by
 				return 0, errors.New("state enc can't be nil")
 			}
 			// no need to construct the validator entries as it is not used here.
-			s, err := s.createState(ctx, enc, nil)
+			s, err := s.unmarshalState(ctx, enc, nil)
 			if err != nil {
 				return 0, err
 			}
-			if s == nil {
+			if s == nil || s.IsNil() {
 				return 0, errors.New("state can't be nil")
 			}
-			return s.Slot, nil
+			return s.Slot(), nil
 		}
-		b := &v1alpha.SignedBeaconBlock{}
+		b := &ethpb.SignedBeaconBlock{}
 		err := decode(ctx, enc, b)
 		if err != nil {
 			return 0, err
@@ -487,7 +528,7 @@ func (s *Store) slotByBlockRoot(ctx context.Context, tx *bolt.Tx, blockRoot []by
 		}
 		return b.Block.Slot, nil
 	}
-	stateSummary := &statepb.StateSummary{}
+	stateSummary := &ethpb.StateSummary{}
 	if err := decode(ctx, enc, stateSummary); err != nil {
 		return 0, err
 	}

beacon-chain/db/kv/state_test.go

@@ -532,6 +532,48 @@ func TestStore_CleanUpDirtyStates_DontDeleteNonFinalized(t *testing.T) {
 	}
 }
 
+func TestAltairState_CanSaveRetrieve(t *testing.T) {
+	db := setupDB(t)
+
+	r := [32]byte{'A'}
+
+	require.Equal(t, false, db.HasState(context.Background(), r))
+
+	st, _ := testutil.DeterministicGenesisStateAltair(t, 1)
+	require.NoError(t, st.SetSlot(100))
+
+	require.NoError(t, db.SaveState(context.Background(), st, r))
+	require.Equal(t, true, db.HasState(context.Background(), r))
+
+	savedS, err := db.State(context.Background(), r)
+	require.NoError(t, err)
+
+	require.DeepSSZEqual(t, st.InnerStateUnsafe(), savedS.InnerStateUnsafe())
+
+	savedS, err = db.State(context.Background(), [32]byte{'B'})
+	require.NoError(t, err)
+	require.Equal(t, state.ReadOnlyBeaconState(nil), savedS, "Unsaved state should've been nil")
+}
+
+func TestAltairState_CanDelete(t *testing.T) {
+	db := setupDB(t)
+
+	r := [32]byte{'A'}
+
+	require.Equal(t, false, db.HasState(context.Background(), r))
+
+	st, _ := testutil.DeterministicGenesisStateAltair(t, 1)
+	require.NoError(t, st.SetSlot(100))
+
+	require.NoError(t, db.SaveState(context.Background(), st, r))
+	require.Equal(t, true, db.HasState(context.Background(), r))
+
+	require.NoError(t, db.DeleteState(context.Background(), r))
+	savedS, err := db.State(context.Background(), r)
+	require.NoError(t, err)
+	require.Equal(t, state.ReadOnlyBeaconState(nil), savedS, "Unsaved state should've been nil")
+}
+
 func validators(limit int) []*ethpb.Validator {
 	var vals []*ethpb.Validator
 	for i := 0; i < limit; i++ {

beacon-chain/gateway/helpers.go

@@ -65,7 +65,7 @@ func DefaultConfig(enableDebugRPCEndpoints bool) MuxConfig {
 	)
 	v1Alpha1PbHandler := gateway.PbMux{
 		Registrations: v1Alpha1Registrations,
-		Patterns:      []string{"/eth/v1alpha1/"},
+		Patterns:      []string{"/prysm/v1alpha1/"},
 		Mux:           v1Alpha1Mux,
 	}
 	v1PbHandler := gateway.PbMux{

beacon-chain/gateway/helpers_test.go

@@ -16,7 +16,7 @@ func TestDefaultConfig(t *testing.T) {
 		assert.Equal(t, 4, len(cfg.V1PbMux.Registrations))
 		assert.NotNil(t, cfg.V1Alpha1PbMux.Mux)
 		require.Equal(t, 1, len(cfg.V1Alpha1PbMux.Patterns))
-		assert.Equal(t, "/eth/v1alpha1/", cfg.V1Alpha1PbMux.Patterns[0])
+		assert.Equal(t, "/prysm/v1alpha1/", cfg.V1Alpha1PbMux.Patterns[0])
 		assert.Equal(t, 4, len(cfg.V1Alpha1PbMux.Registrations))
 	})
 
@@ -28,7 +28,7 @@ func TestDefaultConfig(t *testing.T) {
 		assert.Equal(t, 5, len(cfg.V1PbMux.Registrations))
 		assert.NotNil(t, cfg.V1Alpha1PbMux.Mux)
 		require.Equal(t, 1, len(cfg.V1Alpha1PbMux.Patterns))
-		assert.Equal(t, "/eth/v1alpha1/", cfg.V1Alpha1PbMux.Patterns[0])
+		assert.Equal(t, "/prysm/v1alpha1/", cfg.V1Alpha1PbMux.Patterns[0])
 		assert.Equal(t, 5, len(cfg.V1Alpha1PbMux.Registrations))
 	})
 }

beacon-chain/node/BUILD.bazel

@@ -26,6 +26,7 @@ go_library(
         "//beacon-chain/node/registration:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",
         "//beacon-chain/operations/slashings:go_default_library",
+        "//beacon-chain/operations/synccommittee:go_default_library",
         "//beacon-chain/operations/voluntaryexits:go_default_library",
         "//beacon-chain/p2p:go_default_library",
         "//beacon-chain/powchain:go_default_library",

beacon-chain/node/node.go

@@ -28,6 +28,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/node/registration"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/slashings"
+	"github.com/prysmaticlabs/prysm/beacon-chain/operations/synccommittee"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
 	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
@@ -59,23 +60,24 @@ const testSkipPowFlag = "test-skip-pow"
 // full PoS node. It handles the lifecycle of the entire system and registers
 // services to a service registry.
 type BeaconNode struct {
-	cliCtx          *cli.Context
-	ctx             context.Context
-	cancel          context.CancelFunc
-	services        *shared.ServiceRegistry
-	lock            sync.RWMutex
-	stop            chan struct{} // Channel to wait for termination notifications.
-	db              db.Database
-	attestationPool attestations.Pool
-	exitPool        voluntaryexits.PoolManager
-	slashingsPool   slashings.PoolManager
-	depositCache    *depositcache.DepositCache
-	stateFeed       *event.Feed
-	blockFeed       *event.Feed
-	opFeed          *event.Feed
-	forkChoiceStore forkchoice.ForkChoicer
-	stateGen        *stategen.State
-	collector       *bcnodeCollector
+	cliCtx            *cli.Context
+	ctx               context.Context
+	cancel            context.CancelFunc
+	services          *shared.ServiceRegistry
+	lock              sync.RWMutex
+	stop              chan struct{} // Channel to wait for termination notifications.
+	db                db.Database
+	attestationPool   attestations.Pool
+	exitPool          voluntaryexits.PoolManager
+	slashingsPool     slashings.PoolManager
+	syncCommitteePool synccommittee.Pool
+	depositCache      *depositcache.DepositCache
+	stateFeed         *event.Feed
+	blockFeed         *event.Feed
+	opFeed            *event.Feed
+	forkChoiceStore   forkchoice.ForkChoicer
+	stateGen          *stategen.State
+	collector         *bcnodeCollector
 }
 
 // New creates a new node instance, sets up configuration options, and registers
@@ -95,21 +97,25 @@ func New(cliCtx *cli.Context) (*BeaconNode, error) {
 	configureNetwork(cliCtx)
 	configureInteropConfig(cliCtx)
 
+	// Initializes any forks here.
+	params.BeaconConfig().InitializeForkSchedule()
+
 	registry := shared.NewServiceRegistry()
 
 	ctx, cancel := context.WithCancel(cliCtx.Context)
 	beacon := &BeaconNode{
-		cliCtx:          cliCtx,
-		ctx:             ctx,
-		cancel:          cancel,
-		services:        registry,
-		stop:            make(chan struct{}),
-		stateFeed:       new(event.Feed),
-		blockFeed:       new(event.Feed),
-		opFeed:          new(event.Feed),
-		attestationPool: attestations.NewPool(),
-		exitPool:        voluntaryexits.NewPool(),
-		slashingsPool:   slashings.NewPool(),
+		cliCtx:            cliCtx,
+		ctx:               ctx,
+		cancel:            cancel,
+		services:          registry,
+		stop:              make(chan struct{}),
+		stateFeed:         new(event.Feed),
+		blockFeed:         new(event.Feed),
+		opFeed:            new(event.Feed),
+		attestationPool:   attestations.NewPool(),
+		exitPool:          voluntaryexits.NewPool(),
+		slashingsPool:     slashings.NewPool(),
+		syncCommitteePool: synccommittee.NewPool(),
 	}
 
 	depositAddress, err := registration.DepositContractAddress()
@@ -500,6 +506,7 @@ func (b *BeaconNode) registerSyncService() error {
 		AttPool:           b.attestationPool,
 		ExitPool:          b.exitPool,
 		SlashingPool:      b.slashingsPool,
+		SyncCommsPool:     b.syncCommitteePool,
 		StateGen:          b.stateGen,
 	})
 
@@ -588,6 +595,7 @@ func (b *BeaconNode) registerRPCService() error {
 		AttestationsPool:        b.attestationPool,
 		ExitPool:                b.exitPool,
 		SlashingsPool:           b.slashingsPool,
+		SyncCommitteeObjectPool: b.syncCommitteePool,
 		POWChainService:         web3Service,
 		ChainStartFetcher:       chainStartFetcher,
 		MockEth1Votes:           mockEth1DataVotes,

beacon-chain/operations/synccommittee/contribution.go

@@ -5,7 +5,7 @@ import (
 
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
-	prysmv2 "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/copyutil"
 	"github.com/prysmaticlabs/prysm/shared/queue"
 )
@@ -16,7 +16,7 @@ const syncCommitteeMaxQueueSize = 4
 
 // SaveSyncCommitteeContribution saves a sync committee contribution in to a priority queue.
 // The priority queue is capped at syncCommitteeMaxQueueSize contributions.
-func (s *Store) SaveSyncCommitteeContribution(cont *prysmv2.SyncCommitteeContribution) error {
+func (s *Store) SaveSyncCommitteeContribution(cont *ethpb.SyncCommitteeContribution) error {
 	if cont == nil {
 		return errNilContribution
 	}
@@ -33,7 +33,7 @@ func (s *Store) SaveSyncCommitteeContribution(cont *prysmv2.SyncCommitteeContrib
 
 	// Contributions exist in the queue. Append instead of insert new.
 	if item != nil {
-		contributions, ok := item.Value.([]*prysmv2.SyncCommitteeContribution)
+		contributions, ok := item.Value.([]*ethpb.SyncCommitteeContribution)
 		if !ok {
 			return errors.New("not typed []ethpb.SyncCommitteeContribution")
 		}
@@ -50,7 +50,7 @@ func (s *Store) SaveSyncCommitteeContribution(cont *prysmv2.SyncCommitteeContrib
 	// Contribution does not exist. Insert new.
 	if err := s.contributionCache.Push(&queue.Item{
 		Key:      syncCommitteeKey(cont.Slot),
-		Value:    []*prysmv2.SyncCommitteeContribution{copied},
+		Value:    []*ethpb.SyncCommitteeContribution{copied},
 		Priority: int64(cont.Slot),
 	}); err != nil {
 		return err
@@ -69,7 +69,7 @@ func (s *Store) SaveSyncCommitteeContribution(cont *prysmv2.SyncCommitteeContrib
 
 // SyncCommitteeContributions returns sync committee contributions by slot from the priority queue.
 // Upon retrieval, the contribution is removed from the queue.
-func (s *Store) SyncCommitteeContributions(slot types.Slot) ([]*prysmv2.SyncCommitteeContribution, error) {
+func (s *Store) SyncCommitteeContributions(slot types.Slot) ([]*ethpb.SyncCommitteeContribution, error) {
 	s.contributionLock.RLock()
 	defer s.contributionLock.RUnlock()
 
@@ -78,9 +78,9 @@ func (s *Store) SyncCommitteeContributions(slot types.Slot) ([]*prysmv2.SyncComm
 		return nil, nil
 	}
 
-	contributions, ok := item.Value.([]*prysmv2.SyncCommitteeContribution)
+	contributions, ok := item.Value.([]*ethpb.SyncCommitteeContribution)
 	if !ok {
-		return nil, errors.New("not typed []prysmv2.SyncCommitteeContribution")
+		return nil, errors.New("not typed []ethpb.SyncCommitteeContribution")
 	}
 
 	return contributions, nil

beacon-chain/operations/synccommittee/contribution_test.go

@@ -3,7 +3,7 @@ package synccommittee
 import (
 	"testing"
 
-	prysmv2 "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )
 
@@ -15,7 +15,7 @@ func TestSyncCommitteeContributionCache_Nil(t *testing.T) {
 func TestSyncCommitteeContributionCache_RoundTrip(t *testing.T) {
 	store := NewStore()
 
-	conts := []*prysmv2.SyncCommitteeContribution{
+	conts := []*ethpb.SyncCommitteeContribution{
 		{Slot: 1, SubcommitteeIndex: 0, Signature: []byte{'a'}},
 		{Slot: 1, SubcommitteeIndex: 1, Signature: []byte{'b'}},
 		{Slot: 2, SubcommitteeIndex: 0, Signature: []byte{'c'}},
@@ -36,36 +36,36 @@ func TestSyncCommitteeContributionCache_RoundTrip(t *testing.T) {
 
 	conts, err := store.SyncCommitteeContributions(1)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution(nil), conts)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution(nil), conts)
 
 	conts, err = store.SyncCommitteeContributions(2)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution(nil), conts)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution(nil), conts)
 
 	conts, err = store.SyncCommitteeContributions(3)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 3, SubcommitteeIndex: 0, Signature: []byte{'e'}},
 		{Slot: 3, SubcommitteeIndex: 1, Signature: []byte{'f'}},
 	}, conts)
 
 	conts, err = store.SyncCommitteeContributions(4)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 4, SubcommitteeIndex: 0, Signature: []byte{'g'}},
 		{Slot: 4, SubcommitteeIndex: 1, Signature: []byte{'h'}},
 	}, conts)
 
 	conts, err = store.SyncCommitteeContributions(5)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 5, SubcommitteeIndex: 0, Signature: []byte{'i'}},
 		{Slot: 5, SubcommitteeIndex: 1, Signature: []byte{'j'}},
 	}, conts)
 
 	conts, err = store.SyncCommitteeContributions(6)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 6, SubcommitteeIndex: 0, Signature: []byte{'k'}},
 		{Slot: 6, SubcommitteeIndex: 1, Signature: []byte{'l'}},
 	}, conts)
@@ -73,35 +73,35 @@ func TestSyncCommitteeContributionCache_RoundTrip(t *testing.T) {
 	// All the contributions should persist after get.
 	conts, err = store.SyncCommitteeContributions(1)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution(nil), conts)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution(nil), conts)
 	conts, err = store.SyncCommitteeContributions(2)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution(nil), conts)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution(nil), conts)
 
 	conts, err = store.SyncCommitteeContributions(3)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 3, SubcommitteeIndex: 0, Signature: []byte{'e'}},
 		{Slot: 3, SubcommitteeIndex: 1, Signature: []byte{'f'}},
 	}, conts)
 
 	conts, err = store.SyncCommitteeContributions(4)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 4, SubcommitteeIndex: 0, Signature: []byte{'g'}},
 		{Slot: 4, SubcommitteeIndex: 1, Signature: []byte{'h'}},
 	}, conts)
 
 	conts, err = store.SyncCommitteeContributions(5)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 5, SubcommitteeIndex: 0, Signature: []byte{'i'}},
 		{Slot: 5, SubcommitteeIndex: 1, Signature: []byte{'j'}},
 	}, conts)
 
 	conts, err = store.SyncCommitteeContributions(6)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeContribution{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeContribution{
 		{Slot: 6, SubcommitteeIndex: 0, Signature: []byte{'k'}},
 		{Slot: 6, SubcommitteeIndex: 1, Signature: []byte{'l'}},
 	}, conts)

beacon-chain/operations/synccommittee/message.go

@@ -3,14 +3,14 @@ package synccommittee
 import (
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
-	prysmv2 "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/copyutil"
 	"github.com/prysmaticlabs/prysm/shared/queue"
 )
 
 // SaveSyncCommitteeMessage saves a sync committee message in to a priority queue.
 // The priority queue capped at syncCommitteeMaxQueueSize contributions.
-func (s *Store) SaveSyncCommitteeMessage(msg *prysmv2.SyncCommitteeMessage) error {
+func (s *Store) SaveSyncCommitteeMessage(msg *ethpb.SyncCommitteeMessage) error {
 	if msg == nil {
 		return errNilMessage
 	}
@@ -26,7 +26,7 @@ func (s *Store) SaveSyncCommitteeMessage(msg *prysmv2.SyncCommitteeMessage) erro
 	copied := copyutil.CopySyncCommitteeMessage(msg)
 	// Messages exist in the queue. Append instead of insert new.
 	if item != nil {
-		messages, ok := item.Value.([]*prysmv2.SyncCommitteeMessage)
+		messages, ok := item.Value.([]*ethpb.SyncCommitteeMessage)
 		if !ok {
 			return errors.New("not typed []ethpb.SyncCommitteeMessage")
 		}
@@ -43,7 +43,7 @@ func (s *Store) SaveSyncCommitteeMessage(msg *prysmv2.SyncCommitteeMessage) erro
 	// Message does not exist. Insert new.
 	if err := s.messageCache.Push(&queue.Item{
 		Key:      syncCommitteeKey(msg.Slot),
-		Value:    []*prysmv2.SyncCommitteeMessage{copied},
+		Value:    []*ethpb.SyncCommitteeMessage{copied},
 		Priority: int64(msg.Slot),
 	}); err != nil {
 		return err
@@ -62,7 +62,7 @@ func (s *Store) SaveSyncCommitteeMessage(msg *prysmv2.SyncCommitteeMessage) erro
 
 // SyncCommitteeMessages returns sync committee messages by slot from the priority queue.
 // Upon retrieval, the message is removed from the queue.
-func (s *Store) SyncCommitteeMessages(slot types.Slot) ([]*prysmv2.SyncCommitteeMessage, error) {
+func (s *Store) SyncCommitteeMessages(slot types.Slot) ([]*ethpb.SyncCommitteeMessage, error) {
 	s.messageLock.RLock()
 	defer s.messageLock.RUnlock()
 
@@ -71,9 +71,9 @@ func (s *Store) SyncCommitteeMessages(slot types.Slot) ([]*prysmv2.SyncCommittee
 		return nil, nil
 	}
 
-	messages, ok := item.Value.([]*prysmv2.SyncCommitteeMessage)
+	messages, ok := item.Value.([]*ethpb.SyncCommitteeMessage)
 	if !ok {
-		return nil, errors.New("not typed []prysmv2.SyncCommitteeMessage")
+		return nil, errors.New("not typed []ethpb.SyncCommitteeMessage")
 	}
 
 	return messages, nil

beacon-chain/operations/synccommittee/message_test.go

@@ -3,7 +3,7 @@ package synccommittee
 import (
 	"testing"
 
-	prysmv2 "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )
 
@@ -15,7 +15,7 @@ func TestSyncCommitteeSignatureCache_Nil(t *testing.T) {
 func TestSyncCommitteeSignatureCache_RoundTrip(t *testing.T) {
 	store := NewStore()
 
-	msgs := []*prysmv2.SyncCommitteeMessage{
+	msgs := []*ethpb.SyncCommitteeMessage{
 		{Slot: 1, ValidatorIndex: 0, Signature: []byte{'a'}},
 		{Slot: 1, ValidatorIndex: 1, Signature: []byte{'b'}},
 		{Slot: 2, ValidatorIndex: 0, Signature: []byte{'c'}},
@@ -36,36 +36,36 @@ func TestSyncCommitteeSignatureCache_RoundTrip(t *testing.T) {
 
 	msgs, err := store.SyncCommitteeMessages(1)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage(nil), msgs)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage(nil), msgs)
 
 	msgs, err = store.SyncCommitteeMessages(2)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage(nil), msgs)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage(nil), msgs)
 
 	msgs, err = store.SyncCommitteeMessages(3)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 3, ValidatorIndex: 0, Signature: []byte{'e'}},
 		{Slot: 3, ValidatorIndex: 1, Signature: []byte{'f'}},
 	}, msgs)
 
 	msgs, err = store.SyncCommitteeMessages(4)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 4, ValidatorIndex: 0, Signature: []byte{'g'}},
 		{Slot: 4, ValidatorIndex: 1, Signature: []byte{'h'}},
 	}, msgs)
 
 	msgs, err = store.SyncCommitteeMessages(5)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 5, ValidatorIndex: 0, Signature: []byte{'i'}},
 		{Slot: 5, ValidatorIndex: 1, Signature: []byte{'j'}},
 	}, msgs)
 
 	msgs, err = store.SyncCommitteeMessages(6)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 6, ValidatorIndex: 0, Signature: []byte{'k'}},
 		{Slot: 6, ValidatorIndex: 1, Signature: []byte{'l'}},
 	}, msgs)
@@ -73,36 +73,36 @@ func TestSyncCommitteeSignatureCache_RoundTrip(t *testing.T) {
 	// Messages should persist after retrieval.
 	msgs, err = store.SyncCommitteeMessages(1)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage(nil), msgs)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage(nil), msgs)
 
 	msgs, err = store.SyncCommitteeMessages(2)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage(nil), msgs)
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage(nil), msgs)
 
 	msgs, err = store.SyncCommitteeMessages(3)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 3, ValidatorIndex: 0, Signature: []byte{'e'}},
 		{Slot: 3, ValidatorIndex: 1, Signature: []byte{'f'}},
 	}, msgs)
 
 	msgs, err = store.SyncCommitteeMessages(4)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 4, ValidatorIndex: 0, Signature: []byte{'g'}},
 		{Slot: 4, ValidatorIndex: 1, Signature: []byte{'h'}},
 	}, msgs)
 
 	msgs, err = store.SyncCommitteeMessages(5)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 5, ValidatorIndex: 0, Signature: []byte{'i'}},
 		{Slot: 5, ValidatorIndex: 1, Signature: []byte{'j'}},
 	}, msgs)
 
 	msgs, err = store.SyncCommitteeMessages(6)
 	require.NoError(t, err)
-	require.DeepSSZEqual(t, []*prysmv2.SyncCommitteeMessage{
+	require.DeepSSZEqual(t, []*ethpb.SyncCommitteeMessage{
 		{Slot: 6, ValidatorIndex: 0, Signature: []byte{'k'}},
 		{Slot: 6, ValidatorIndex: 1, Signature: []byte{'l'}},
 	}, msgs)

beacon-chain/operations/synccommittee/pool.go

@@ -2,7 +2,7 @@ package synccommittee
 
 import (
 	types "github.com/prysmaticlabs/eth2-types"
-	prysmv2 "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 )
 
 var _ = Pool(&Store{})
@@ -13,12 +13,12 @@ var _ = Pool(&Store{})
 // sync aggregators.
 type Pool interface {
 	// Methods for Sync Contributions.
-	SaveSyncCommitteeContribution(contr *prysmv2.SyncCommitteeContribution) error
-	SyncCommitteeContributions(slot types.Slot) ([]*prysmv2.SyncCommitteeContribution, error)
+	SaveSyncCommitteeContribution(contr *ethpb.SyncCommitteeContribution) error
+	SyncCommitteeContributions(slot types.Slot) ([]*ethpb.SyncCommitteeContribution, error)
 
 	// Methods for Sync Committee Messages.
-	SaveSyncCommitteeMessage(sig *prysmv2.SyncCommitteeMessage) error
-	SyncCommitteeMessages(slot types.Slot) ([]*prysmv2.SyncCommitteeMessage, error)
+	SaveSyncCommitteeMessage(sig *ethpb.SyncCommitteeMessage) error
+	SyncCommitteeMessages(slot types.Slot) ([]*ethpb.SyncCommitteeMessage, error)
 }
 
 // NewPool returns the sync committee store fulfilling the pool interface.

beacon-chain/p2p/BUILD.bazel

@@ -11,6 +11,7 @@ go_library(
         "discovery.go",
         "doc.go",
         "fork.go",
+        "fork_watcher.go",
         "gossip_scoring_params.go",
         "gossip_topic_mappings.go",
         "handshake.go",
@@ -39,6 +40,7 @@ go_library(
     ],
     deps = [
         "//beacon-chain/cache:go_default_library",
+        "//beacon-chain/core/altair:go_default_library",
         "//beacon-chain/core/feed:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
@@ -53,6 +55,7 @@ go_library(
         "//proto/prysm/v1alpha1/metadata:go_default_library",
         "//proto/prysm/v1alpha1/wrapper:go_default_library",
         "//shared:go_default_library",
+        "//shared/bytesutil:go_default_library",
         "//shared/featureconfig:go_default_library",
         "//shared/fileutil:go_default_library",
         "//shared/hashutil:go_default_library",
@@ -68,8 +71,10 @@ go_library(
         "@com_github_ethereum_go_ethereum//p2p/discover:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/enr:go_default_library",
+        "@com_github_ferranbt_fastssz//:go_default_library",
         "@com_github_ipfs_go_ipfs_addr//:go_default_library",
         "@com_github_kevinms_leakybucket_go//:go_default_library",
+        "@com_github_kr_pretty//:go_default_library",
         "@com_github_libp2p_go_libp2p//:go_default_library",
         "@com_github_libp2p_go_libp2p//config:go_default_library",
         "@com_github_libp2p_go_libp2p//p2p/protocol/identify:go_default_library",
@@ -147,6 +152,7 @@ go_test(
         "//shared/testutil/assert:go_default_library",
         "//shared/testutil/require:go_default_library",
         "//shared/timeutils:go_default_library",
+        "//shared/version:go_default_library",
         "@com_github_ethereum_go_ethereum//crypto:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/discover:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
@@ -164,6 +170,7 @@ go_test(
         "@com_github_libp2p_go_libp2p_pubsub//pb:go_default_library",
         "@com_github_libp2p_go_libp2p_swarm//testing:go_default_library",
         "@com_github_multiformats_go_multiaddr//:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",

beacon-chain/p2p/broadcaster.go

@@ -7,8 +7,12 @@ import (
 	"reflect"
 	"time"
 
+	ssz "github.com/ferranbt/fastssz"
 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	eth "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/traceutil"
@@ -20,7 +24,8 @@ import (
 // GossipTypeMapping.
 var ErrMessageNotMapped = errors.New("message type is not mapped to a PubSub topic")
 
-// Broadcast a message to the p2p network.
+// Broadcasts a message to the p2p network, the message is assumed to be
+// broadcasted to the current fork.
 func (s *Service) Broadcast(ctx context.Context, msg proto.Message) error {
 	ctx, span := trace.StartSpan(ctx, "p2p.Broadcast")
 	defer span.End()
@@ -29,7 +34,7 @@ func (s *Service) Broadcast(ctx context.Context, msg proto.Message) error {
 	ctx, cancel := context.WithTimeout(ctx, twoSlots)
 	defer cancel()
 
-	forkDigest, err := s.forkDigest()
+	forkDigest, err := s.currentForkDigest()
 	if err != nil {
 		err := errors.Wrap(err, "could not retrieve fork digest")
 		traceutil.AnnotateError(span, err)
@@ -41,14 +46,19 @@ func (s *Service) Broadcast(ctx context.Context, msg proto.Message) error {
 		traceutil.AnnotateError(span, ErrMessageNotMapped)
 		return ErrMessageNotMapped
 	}
-	return s.broadcastObject(ctx, msg, fmt.Sprintf(topic, forkDigest))
+	castMsg, ok := msg.(ssz.Marshaler)
+	if !ok {
+		return errors.Errorf("message of %T does not support marshaller interface", msg)
+	}
+	return s.broadcastObject(ctx, castMsg, fmt.Sprintf(topic, forkDigest))
 }
 
-// BroadcastAttestation broadcasts an attestation to the p2p network.
+// BroadcastAttestation broadcasts an attestation to the p2p network, the message is assumed to be
+// broadcasted to the current fork.
 func (s *Service) BroadcastAttestation(ctx context.Context, subnet uint64, att *eth.Attestation) error {
 	ctx, span := trace.StartSpan(ctx, "p2p.BroadcastAttestation")
 	defer span.End()
-	forkDigest, err := s.forkDigest()
+	forkDigest, err := s.currentForkDigest()
 	if err != nil {
 		err := errors.Wrap(err, "could not retrieve fork digest")
 		traceutil.AnnotateError(span, err)
@@ -61,6 +71,24 @@ func (s *Service) BroadcastAttestation(ctx context.Context, subnet uint64, att *
 	return nil
 }
 
+// BroadcastAttestation broadcasts an attestation to the p2p network, the message is assumed to be
+// broadcasted to the current fork.
+func (s *Service) BroadcastSyncCommitteeMessage(ctx context.Context, subnet uint64, sMsg *ethpb.SyncCommitteeMessage) error {
+	ctx, span := trace.StartSpan(ctx, "p2p.BroadcastSyncCommitteeMessage")
+	defer span.End()
+	forkDigest, err := s.currentForkDigest()
+	if err != nil {
+		err := errors.Wrap(err, "could not retrieve fork digest")
+		traceutil.AnnotateError(span, err)
+		return err
+	}
+
+	// Non-blocking broadcast, with attempts to discover a subnet peer if none available.
+	go s.broadcastSyncCommittee(ctx, subnet, sMsg, forkDigest)
+
+	return nil
+}
+
 func (s *Service) broadcastAttestation(ctx context.Context, subnet uint64, att *eth.Attestation, forkDigest [4]byte) {
 	ctx, span := trace.StartSpan(ctx, "p2p.broadcastAttestation")
 	defer span.End()
@@ -100,6 +128,13 @@ func (s *Service) broadcastAttestation(ctx context.Context, subnet uint64, att *
 			traceutil.AnnotateError(span, err)
 		}
 	}
+	// In the event our attestation is outdated and beyond the
+	// acceptable threshold, we exit early and do not broadcast it.
+	currSlot := helpers.CurrentSlot(uint64(s.genesisTime.Unix()))
+	if att.Data.Slot+params.BeaconConfig().SlotsPerEpoch < currSlot {
+		log.Warnf("Attestation is too old to broadcast, discarding it. Current Slot: %d , Attestation Slot: %d", currSlot, att.Data.Slot)
+		return
+	}
 
 	if err := s.broadcastObject(ctx, att, attestationToTopic(subnet, forkDigest)); err != nil {
 		log.WithError(err).Error("Failed to broadcast attestation")
@@ -107,8 +142,63 @@ func (s *Service) broadcastAttestation(ctx context.Context, subnet uint64, att *
 	}
 }
 
+func (s *Service) broadcastSyncCommittee(ctx context.Context, subnet uint64, sMsg *ethpb.SyncCommitteeMessage, forkDigest [4]byte) {
+	ctx, span := trace.StartSpan(ctx, "p2p.broadcastSyncCommittee")
+	defer span.End()
+	ctx = trace.NewContext(context.Background(), span) // clear parent context / deadline.
+
+	oneSlot := time.Duration(1*params.BeaconConfig().SecondsPerSlot) * time.Second
+	ctx, cancel := context.WithTimeout(ctx, oneSlot)
+	defer cancel()
+
+	// Ensure we have peers with this subnet.
+	// This adds in a special value to the subnet
+	// to ensure that we can re-use the same subnet locker.
+	wrappedSubIdx := subnet + syncLockerVal
+	s.subnetLocker(wrappedSubIdx).RLock()
+	hasPeer := s.hasPeerWithSubnet(syncCommitteeToTopic(subnet, forkDigest))
+	s.subnetLocker(wrappedSubIdx).RUnlock()
+
+	span.AddAttributes(
+		trace.BoolAttribute("hasPeer", hasPeer),
+		trace.Int64Attribute("slot", int64(sMsg.Slot)),
+		trace.Int64Attribute("subnet", int64(subnet)),
+	)
+
+	if !hasPeer {
+		syncCommitteeBroadcastAttempts.Inc()
+		if err := func() error {
+			s.subnetLocker(wrappedSubIdx).Lock()
+			defer s.subnetLocker(wrappedSubIdx).Unlock()
+			ok, err := s.FindPeersWithSubnet(ctx, syncCommitteeToTopic(subnet, forkDigest), subnet, 1)
+			if err != nil {
+				return err
+			}
+			if ok {
+				savedSyncCommitteeBroadcasts.Inc()
+				return nil
+			}
+			return errors.New("failed to find peers for subnet")
+		}(); err != nil {
+			log.WithError(err).Error("Failed to find peers")
+			traceutil.AnnotateError(span, err)
+		}
+	}
+	// In the event our sync message is outdated and beyond the
+	// acceptable threshold, we exit early and do not broadcast it.
+	if err := altair.ValidateSyncMessageTime(sMsg.Slot, s.genesisTime, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
+		log.Warnf("Sync Committee Message is too old to broadcast, discarding it. %v", err)
+		return
+	}
+
+	if err := s.broadcastObject(ctx, sMsg, syncCommitteeToTopic(subnet, forkDigest)); err != nil {
+		log.WithError(err).Error("Failed to broadcast sync committee message")
+		traceutil.AnnotateError(span, err)
+	}
+}
+
 // method to broadcast messages to other peers in our gossip mesh.
-func (s *Service) broadcastObject(ctx context.Context, obj interface{}, topic string) error {
+func (s *Service) broadcastObject(ctx context.Context, obj ssz.Marshaler, topic string) error {
 	_, span := trace.StartSpan(ctx, "p2p.broadcastObject")
 	defer span.End()
 
@@ -126,7 +216,6 @@ func (s *Service) broadcastObject(ctx context.Context, obj interface{}, topic st
 		messageLen := int64(buf.Len())
 		span.AddMessageSendEvent(int64(id), messageLen /*uncompressed*/, messageLen /*compressed*/)
 	}
-
 	if err := s.PublishToTopic(ctx, topic+s.Encoding().ProtocolSuffix(), buf.Bytes()); err != nil {
 		err := errors.Wrap(err, "could not publish message")
 		traceutil.AnnotateError(span, err)
@@ -138,3 +227,7 @@ func (s *Service) broadcastObject(ctx context.Context, obj interface{}, topic st
 func attestationToTopic(subnet uint64, forkDigest [4]byte) string {
 	return fmt.Sprintf(AttestationSubnetTopicFormat, forkDigest, subnet)
 }
+
+func syncCommitteeToTopic(subnet uint64, forkDigest [4]byte) string {
+	return fmt.Sprintf(SyncCommitteeSubnetTopicFormat, forkDigest, subnet)
+}

beacon-chain/p2p/broadcaster_test.go

@@ -18,8 +18,8 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/peers/scorers"
 	p2ptest "github.com/prysmaticlabs/prysm/beacon-chain/p2p/testing"
 	eth "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	pb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
 	testpb "github.com/prysmaticlabs/prysm/proto/testing"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
@@ -46,7 +46,7 @@ func TestService_Broadcast(t *testing.T) {
 		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
 	}
 
-	msg := &statepb.Fork{
+	msg := &ethpb.Fork{
 		Epoch:           55,
 		CurrentVersion:  []byte("fooo"),
 		PreviousVersion: []byte("barr"),
@@ -55,7 +55,7 @@ func TestService_Broadcast(t *testing.T) {
 	topic := "/eth2/%x/testing"
 	// Set a test gossip mapping for testpb.TestSimpleMessage.
 	GossipTypeMapping[reflect.TypeOf(msg)] = topic
-	digest, err := p.forkDigest()
+	digest, err := p.currentForkDigest()
 	require.NoError(t, err)
 	topic = fmt.Sprintf(topic, digest)
 
@@ -77,7 +77,7 @@ func TestService_Broadcast(t *testing.T) {
 		incomingMessage, err := sub.Next(ctx)
 		require.NoError(t, err)
 
-		result := &statepb.Fork{}
+		result := &ethpb.Fork{}
 		require.NoError(t, p.Encoding().DecodeGossip(incomingMessage.Data, result))
 		if !proto.Equal(result, msg) {
 			tt.Errorf("Did not receive expected message, got %+v, wanted %+v", result, msg)
@@ -169,7 +169,7 @@ func TestService_BroadcastAttestation(t *testing.T) {
 
 	topic := AttestationSubnetTopicFormat
 	GossipTypeMapping[reflect.TypeOf(msg)] = topic
-	digest, err := p.forkDigest()
+	digest, err := p.currentForkDigest()
 	require.NoError(t, err)
 	topic = fmt.Sprintf(topic, digest, subnet)
 
@@ -326,7 +326,7 @@ func TestService_BroadcastAttestationWithDiscoveryAttempts(t *testing.T) {
 	msg := testutil.HydrateAttestation(&eth.Attestation{AggregationBits: bitfield.NewBitlist(7)})
 	topic := AttestationSubnetTopicFormat
 	GossipTypeMapping[reflect.TypeOf(msg)] = topic
-	digest, err := p.forkDigest()
+	digest, err := p.currentForkDigest()
 	require.NoError(t, err)
 	topic = fmt.Sprintf(topic, digest, subnet)
 
@@ -365,3 +365,66 @@ func TestService_BroadcastAttestationWithDiscoveryAttempts(t *testing.T) {
 		t.Error("Failed to receive pubsub within 4s")
 	}
 }
+
+func TestService_BroadcastSyncCommittee(t *testing.T) {
+	p1 := p2ptest.NewTestP2P(t)
+	p2 := p2ptest.NewTestP2P(t)
+	p1.Connect(p2)
+	if len(p1.BHost.Network().Peers()) == 0 {
+		t.Fatal("No peers")
+	}
+
+	p := &Service{
+		host:                  p1.BHost,
+		pubsub:                p1.PubSub(),
+		joinedTopics:          map[string]*pubsub.Topic{},
+		cfg:                   &Config{},
+		genesisTime:           time.Now(),
+		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+		subnetsLock:           make(map[uint64]*sync.RWMutex),
+		subnetsLockLock:       sync.Mutex{},
+		peers: peers.NewStatus(context.Background(), &peers.StatusConfig{
+			ScorerParams: &scorers.Config{},
+		}),
+	}
+
+	msg := testutil.HydrateSyncCommittee(&pb.SyncCommitteeMessage{})
+	subnet := uint64(5)
+
+	topic := SyncCommitteeSubnetTopicFormat
+	GossipTypeMapping[reflect.TypeOf(msg)] = topic
+	digest, err := p.currentForkDigest()
+	require.NoError(t, err)
+	topic = fmt.Sprintf(topic, digest, subnet)
+
+	// External peer subscribes to the topic.
+	topic += p.Encoding().ProtocolSuffix()
+	sub, err := p2.SubscribeToTopic(topic)
+	require.NoError(t, err)
+
+	time.Sleep(50 * time.Millisecond) // libp2p fails without this delay...
+
+	// Async listen for the pubsub, must be before the broadcast.
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func(tt *testing.T) {
+		defer wg.Done()
+		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+		defer cancel()
+
+		incomingMessage, err := sub.Next(ctx)
+		require.NoError(t, err)
+
+		result := &pb.SyncCommitteeMessage{}
+		require.NoError(t, p.Encoding().DecodeGossip(incomingMessage.Data, result))
+		if !proto.Equal(result, msg) {
+			tt.Errorf("Did not receive expected message, got %+v, wanted %+v", result, msg)
+		}
+	}(t)
+
+	// Broadcast to peers and wait.
+	require.NoError(t, p.BroadcastSyncCommitteeMessage(context.Background(), subnet, msg))
+	if testutil.WaitTimeout(&wg, 1*time.Second) {
+		t.Error("Failed to receive pubsub within 1s")
+	}
+}

beacon-chain/p2p/discovery.go

@@ -16,6 +16,9 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/version"
 )
 
 // Listener defines the discovery V5 network interface that is used
@@ -36,7 +39,7 @@ type Listener interface {
 // to be dynamically discoverable by others given our tracked committee ids.
 func (s *Service) RefreshENR() {
 	// return early if discv5 isnt running
-	if s.dv5Listener == nil {
+	if s.dv5Listener == nil || !s.isInitialized() {
 		return
 	}
 	bitV := bitfield.NewBitvector64()
@@ -44,16 +47,43 @@ func (s *Service) RefreshENR() {
 	for _, idx := range committees {
 		bitV.SetBitAt(idx, true)
 	}
-	currentBitV, err := bitvector(s.dv5Listener.Self().Record())
+	currentBitV, err := attBitvector(s.dv5Listener.Self().Record())
 	if err != nil {
-		log.Errorf("Could not retrieve bitfield: %v", err)
+		log.Errorf("Could not retrieve att bitfield: %v", err)
 		return
 	}
-	if bytes.Equal(bitV, currentBitV) {
-		// return early if bitfield hasn't changed
-		return
+	// Compare current epoch with our fork epochs
+	currEpoch := helpers.SlotToEpoch(helpers.CurrentSlot(uint64(s.genesisTime.Unix())))
+	altairForkEpoch := params.BeaconConfig().AltairForkEpoch
+	switch {
+	// Altair Behaviour
+	case currEpoch >= altairForkEpoch:
+		// Retrieve sync subnets from application level
+		// cache.
+		bitS := bitfield.Bitvector4{byte(0x00)}
+		committees = cache.SyncSubnetIDs.GetAllSubnets(currEpoch)
+		for _, idx := range committees {
+			bitS.SetBitAt(idx, true)
+		}
+		currentBitS, err := syncBitvector(s.dv5Listener.Self().Record())
+		if err != nil {
+			log.Errorf("Could not retrieve sync bitfield: %v", err)
+			return
+		}
+		if bytes.Equal(bitV, currentBitV) && bytes.Equal(bitS, currentBitS) &&
+			s.Metadata().Version() == version.Altair {
+			// return early if bitfields haven't changed
+			return
+		}
+		s.updateSubnetRecordWithMetadataV2(bitV, bitS)
+	default:
+		// Phase 0 behaviour.
+		if bytes.Equal(bitV, currentBitV) {
+			// return early if bitfield hasn't changed
+			return
+		}
+		s.updateSubnetRecordWithMetadata(bitV)
 	}
-	s.updateSubnetRecordWithMetadata(bitV)
 	// ping all peers to inform them of new metadata
 	s.pingPeers()
 }
@@ -206,7 +236,8 @@ func (s *Service) createLocalNode(
 	if err != nil {
 		return nil, errors.Wrap(err, "could not add eth2 fork version entry to enr")
 	}
-	return intializeAttSubnets(localNode), nil
+	localNode = initializeAttSubnets(localNode)
+	return initializeSyncCommSubnets(localNode), nil
 }
 
 func (s *Service) startDiscoveryV5(

beacon-chain/p2p/discovery_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/libp2p/go-libp2p-core/peer"
 	"github.com/prysmaticlabs/go-bitfield"
 	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/peers"
@@ -33,8 +34,10 @@ import (
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/iputils"
+	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"github.com/prysmaticlabs/prysm/shared/version"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )
 
@@ -340,3 +343,163 @@ func addPeer(t *testing.T, p *peers.Status, state peerdata.PeerConnectionState)
 	}))
 	return id
 }
+
+func TestRefreshENR_ForkBoundaries(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	// Clean up caches after usage.
+	defer cache.SubnetIDs.EmptyAllCaches()
+	defer cache.SubnetIDs.EmptyAllCaches()
+
+	tests := []struct {
+		name           string
+		svcBuilder     func(t *testing.T) *Service
+		postValidation func(t *testing.T, s *Service)
+	}{
+		{
+			name: "metadata no change",
+			svcBuilder: func(t *testing.T) *Service {
+				port := 2000
+				ipAddr, pkey := createAddrAndPrivKey(t)
+				s := &Service{
+					genesisTime:           time.Now(),
+					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+					cfg:                   &Config{UDPPort: uint(port)},
+				}
+				listener, err := s.createListener(ipAddr, pkey)
+				assert.NoError(t, err)
+				s.dv5Listener = listener
+				s.metaData = wrapper.WrappedMetadataV0(new(pb.MetaDataV0))
+				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
+				return s
+			},
+			postValidation: func(t *testing.T, s *Service) {
+				assert.DeepEqual(t, bitfield.NewBitvector64(), s.metaData.AttnetsBitfield())
+			},
+		},
+		{
+			name: "metadata updated",
+			svcBuilder: func(t *testing.T) *Service {
+				port := 2000
+				ipAddr, pkey := createAddrAndPrivKey(t)
+				s := &Service{
+					genesisTime:           time.Now(),
+					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+					cfg:                   &Config{UDPPort: uint(port)},
+				}
+				listener, err := s.createListener(ipAddr, pkey)
+				assert.NoError(t, err)
+				s.dv5Listener = listener
+				s.metaData = wrapper.WrappedMetadataV0(new(pb.MetaDataV0))
+				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})
+				cache.SubnetIDs.AddPersistentCommittee([]byte{'A'}, []uint64{1, 2, 3, 23}, 0)
+				return s
+			},
+			postValidation: func(t *testing.T, s *Service) {
+				assert.DeepEqual(t, bitfield.Bitvector64{0xe, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0}, s.metaData.AttnetsBitfield())
+			},
+		},
+		{
+			name: "metadata updated at fork epoch",
+			svcBuilder: func(t *testing.T) *Service {
+				port := 2000
+				ipAddr, pkey := createAddrAndPrivKey(t)
+				s := &Service{
+					genesisTime:           time.Now().Add(-5 * oneEpochDuration()),
+					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+					cfg:                   &Config{UDPPort: uint(port)},
+				}
+				listener, err := s.createListener(ipAddr, pkey)
+				assert.NoError(t, err)
+
+				// Update params
+				cfg := params.BeaconConfig()
+				cfg.AltairForkEpoch = 5
+				params.OverrideBeaconConfig(cfg)
+				params.BeaconConfig().InitializeForkSchedule()
+
+				s.dv5Listener = listener
+				s.metaData = wrapper.WrappedMetadataV0(new(pb.MetaDataV0))
+				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})
+				cache.SubnetIDs.AddPersistentCommittee([]byte{'A'}, []uint64{1, 2, 3, 23}, 0)
+				return s
+			},
+			postValidation: func(t *testing.T, s *Service) {
+				assert.Equal(t, version.Altair, s.metaData.Version())
+				assert.DeepEqual(t, bitfield.Bitvector4{0x00}, s.metaData.MetadataObjV1().Syncnets)
+				assert.DeepEqual(t, bitfield.Bitvector64{0xe, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0}, s.metaData.AttnetsBitfield())
+			},
+		},
+		{
+			name: "metadata updated at fork epoch with no bitfield",
+			svcBuilder: func(t *testing.T) *Service {
+				port := 2000
+				ipAddr, pkey := createAddrAndPrivKey(t)
+				s := &Service{
+					genesisTime:           time.Now().Add(-5 * oneEpochDuration()),
+					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+					cfg:                   &Config{UDPPort: uint(port)},
+				}
+				listener, err := s.createListener(ipAddr, pkey)
+				assert.NoError(t, err)
+
+				// Update params
+				cfg := params.BeaconConfig()
+				cfg.AltairForkEpoch = 5
+				params.OverrideBeaconConfig(cfg)
+				params.BeaconConfig().InitializeForkSchedule()
+
+				s.dv5Listener = listener
+				s.metaData = wrapper.WrappedMetadataV0(new(pb.MetaDataV0))
+				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
+				return s
+			},
+			postValidation: func(t *testing.T, s *Service) {
+				assert.Equal(t, version.Altair, s.metaData.Version())
+				assert.DeepEqual(t, bitfield.Bitvector4{0x00}, s.metaData.MetadataObjV1().Syncnets)
+				assert.DeepEqual(t, bitfield.Bitvector64{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, s.metaData.AttnetsBitfield())
+			},
+		},
+		{
+			name: "metadata updated past fork epoch with bitfields",
+			svcBuilder: func(t *testing.T) *Service {
+				port := 2000
+				ipAddr, pkey := createAddrAndPrivKey(t)
+				s := &Service{
+					genesisTime:           time.Now().Add(-6 * oneEpochDuration()),
+					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+					cfg:                   &Config{UDPPort: uint(port)},
+				}
+				listener, err := s.createListener(ipAddr, pkey)
+				assert.NoError(t, err)
+
+				// Update params
+				cfg := params.BeaconConfig()
+				cfg.AltairForkEpoch = 5
+				params.OverrideBeaconConfig(cfg)
+				params.BeaconConfig().InitializeForkSchedule()
+
+				s.dv5Listener = listener
+				s.metaData = wrapper.WrappedMetadataV0(new(pb.MetaDataV0))
+				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
+				cache.SubnetIDs.AddPersistentCommittee([]byte{'A'}, []uint64{1, 2, 3, 23}, 0)
+				cache.SyncSubnetIDs.AddSyncCommitteeSubnets([]byte{'A'}, 0, []uint64{0, 1}, 0)
+				return s
+			},
+			postValidation: func(t *testing.T, s *Service) {
+				assert.Equal(t, version.Altair, s.metaData.Version())
+				assert.DeepEqual(t, bitfield.Bitvector4{0x03}, s.metaData.MetadataObjV1().Syncnets)
+				assert.DeepEqual(t, bitfield.Bitvector64{0xe, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0}, s.metaData.AttnetsBitfield())
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := tt.svcBuilder(t)
+			s.RefreshENR()
+			tt.postValidation(t, s)
+			s.dv5Listener.Close()
+			cache.SubnetIDs.EmptyAllCaches()
+			cache.SyncSubnetIDs.EmptyAllCaches()
+		})
+	}
+}

beacon-chain/p2p/encoder/network_encoding.go

@@ -2,20 +2,22 @@ package encoder
 
 import (
 	"io"
+
+	ssz "github.com/ferranbt/fastssz"
 )
 
 // NetworkEncoding represents an encoder compatible with Ethereum consensus p2p.
 type NetworkEncoding interface {
 	// DecodeGossip to the provided gossip message. The interface must be a pointer to the decoding destination.
-	DecodeGossip([]byte, interface{}) error
+	DecodeGossip([]byte, ssz.Unmarshaler) error
 	// DecodeWithMaxLength a bytes from a reader with a varint length prefix. The interface must be a pointer to the
 	// decoding destination. The length of the message should not be more than the provided limit.
-	DecodeWithMaxLength(io.Reader, interface{}) error
+	DecodeWithMaxLength(io.Reader, ssz.Unmarshaler) error
 	// EncodeGossip an arbitrary gossip message to the provided writer. The interface must be a pointer object to encode.
-	EncodeGossip(io.Writer, interface{}) (int, error)
+	EncodeGossip(io.Writer, ssz.Marshaler) (int, error)
 	// EncodeWithMaxLength an arbitrary message to the provided writer with a varint length prefix. The interface must be
 	// a pointer object to encode. The encoded message should not be bigger than the provided limit.
-	EncodeWithMaxLength(io.Writer, interface{}) (int, error)
+	EncodeWithMaxLength(io.Writer, ssz.Marshaler) (int, error)
 	// ProtocolSuffix returns the last part of the protocol ID to indicate the encoding scheme.
 	ProtocolSuffix() string
 }

beacon-chain/p2p/encoder/ssz.go

@@ -33,15 +33,12 @@ type SszNetworkEncoder struct{}
 // ProtocolSuffixSSZSnappy is the last part of the topic string to identify the encoding protocol.
 const ProtocolSuffixSSZSnappy = "ssz_snappy"
 
-func (e SszNetworkEncoder) doEncode(msg interface{}) ([]byte, error) {
-	if v, ok := msg.(fastssz.Marshaler); ok {
-		return v.MarshalSSZ()
-	}
-	return nil, errors.Errorf("non-supported type: %T", msg)
+func (e SszNetworkEncoder) doEncode(msg fastssz.Marshaler) ([]byte, error) {
+	return msg.MarshalSSZ()
 }
 
 // EncodeGossip the proto gossip message to the io.Writer.
-func (e SszNetworkEncoder) EncodeGossip(w io.Writer, msg interface{}) (int, error) {
+func (e SszNetworkEncoder) EncodeGossip(w io.Writer, msg fastssz.Marshaler) (int, error) {
 	if msg == nil {
 		return 0, nil
 	}
@@ -58,7 +55,7 @@ func (e SszNetworkEncoder) EncodeGossip(w io.Writer, msg interface{}) (int, erro
 
 // EncodeWithMaxLength the proto message to the io.Writer. This encoding prefixes the byte slice with a protobuf varint
 // to indicate the size of the message. This checks that the encoded message isn't larger than the provided max limit.
-func (e SszNetworkEncoder) EncodeWithMaxLength(w io.Writer, msg interface{}) (int, error) {
+func (e SszNetworkEncoder) EncodeWithMaxLength(w io.Writer, msg fastssz.Marshaler) (int, error) {
 	if msg == nil {
 		return 0, nil
 	}
@@ -81,15 +78,12 @@ func (e SszNetworkEncoder) EncodeWithMaxLength(w io.Writer, msg interface{}) (in
 	return writeSnappyBuffer(w, b)
 }
 
-func (e SszNetworkEncoder) doDecode(b []byte, to interface{}) error {
-	if v, ok := to.(fastssz.Unmarshaler); ok {
-		return v.UnmarshalSSZ(b)
-	}
-	return errors.Errorf("non-supported type: %T", to)
+func (e SszNetworkEncoder) doDecode(b []byte, to fastssz.Unmarshaler) error {
+	return to.UnmarshalSSZ(b)
 }
 
 // DecodeGossip decodes the bytes to the protobuf gossip message provided.
-func (e SszNetworkEncoder) DecodeGossip(b []byte, to interface{}) error {
+func (e SszNetworkEncoder) DecodeGossip(b []byte, to fastssz.Unmarshaler) error {
 	b, err := DecodeSnappy(b, MaxGossipSize)
 	if err != nil {
 		return err
@@ -115,7 +109,7 @@ func DecodeSnappy(msg []byte, maxSize uint64) ([]byte, error) {
 
 // DecodeWithMaxLength the bytes from io.Reader to the protobuf message provided.
 // This checks that the decoded message isn't larger than the provided max limit.
-func (e SszNetworkEncoder) DecodeWithMaxLength(r io.Reader, to interface{}) error {
+func (e SszNetworkEncoder) DecodeWithMaxLength(r io.Reader, to fastssz.Unmarshaler) error {
 	msgLen, err := readVarint(r)
 	if err != nil {
 		return err

beacon-chain/p2p/encoder/ssz_test.go

@@ -10,7 +10,7 @@ import (
 
 	gogo "github.com/gogo/protobuf/proto"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/encoder"
-	statepb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
@@ -26,7 +26,7 @@ func TestSszNetworkEncoder_RoundTrip(t *testing.T) {
 
 func TestSszNetworkEncoder_FailsSnappyLength(t *testing.T) {
 	e := &encoder.SszNetworkEncoder{}
-	att := &statepb.Fork{}
+	att := &ethpb.Fork{}
 	data := make([]byte, 32)
 	binary.PutUvarint(data, encoder.MaxGossipSize+32)
 	err := e.DecodeGossip(data, att)
@@ -35,14 +35,14 @@ func TestSszNetworkEncoder_FailsSnappyLength(t *testing.T) {
 
 func testRoundTripWithLength(t *testing.T, e *encoder.SszNetworkEncoder) {
 	buf := new(bytes.Buffer)
-	msg := &statepb.Fork{
+	msg := &ethpb.Fork{
 		PreviousVersion: []byte("fooo"),
 		CurrentVersion:  []byte("barr"),
 		Epoch:           9001,
 	}
 	_, err := e.EncodeWithMaxLength(buf, msg)
 	require.NoError(t, err)
-	decoded := &statepb.Fork{}
+	decoded := &ethpb.Fork{}
 	require.NoError(t, e.DecodeWithMaxLength(buf, decoded))
 	if !proto.Equal(decoded, msg) {
 		t.Logf("decoded=%+v\n", decoded)
@@ -52,14 +52,14 @@ func testRoundTripWithLength(t *testing.T, e *encoder.SszNetworkEncoder) {
 
 func testRoundTripWithGossip(t *testing.T, e *encoder.SszNetworkEncoder) {
 	buf := new(bytes.Buffer)
-	msg := &statepb.Fork{
+	msg := &ethpb.Fork{
 		PreviousVersion: []byte("fooo"),
 		CurrentVersion:  []byte("barr"),
 		Epoch:           9001,
 	}
 	_, err := e.EncodeGossip(buf, msg)
 	require.NoError(t, err)
-	decoded := &statepb.Fork{}
+	decoded := &ethpb.Fork{}
 	require.NoError(t, e.DecodeGossip(buf.Bytes(), decoded))
 	if !proto.Equal(decoded, msg) {
 		t.Logf("decoded=%+v\n", decoded)
@@ -69,7 +69,7 @@ func testRoundTripWithGossip(t *testing.T, e *encoder.SszNetworkEncoder) {
 
 func TestSszNetworkEncoder_EncodeWithMaxLength(t *testing.T) {
 	buf := new(bytes.Buffer)
-	msg := &statepb.Fork{
+	msg := &ethpb.Fork{
 		PreviousVersion: []byte("fooo"),
 		CurrentVersion:  []byte("barr"),
 		Epoch:           9001,
@@ -86,7 +86,7 @@ func TestSszNetworkEncoder_EncodeWithMaxLength(t *testing.T) {
 
 func TestSszNetworkEncoder_DecodeWithMaxLength(t *testing.T) {
 	buf := new(bytes.Buffer)
-	msg := &statepb.Fork{
+	msg := &ethpb.Fork{
 		PreviousVersion: []byte("fooo"),
 		CurrentVersion:  []byte("barr"),
 		Epoch:           4242,
@@ -99,7 +99,7 @@ func TestSszNetworkEncoder_DecodeWithMaxLength(t *testing.T) {
 	params.OverrideBeaconNetworkConfig(c)
 	_, err := e.EncodeGossip(buf, msg)
 	require.NoError(t, err)
-	decoded := &statepb.Fork{}
+	decoded := &ethpb.Fork{}
 	err = e.DecodeWithMaxLength(buf, decoded)
 	wanted := fmt.Sprintf("goes over the provided max limit of %d", maxChunkSize)
 	assert.ErrorContains(t, wanted, err)
@@ -115,13 +115,13 @@ func TestSszNetworkEncoder_DecodeWithMultipleFrames(t *testing.T) {
 	maxChunkSize := uint64(1 << 22)
 	c.MaxChunkSize = maxChunkSize
 	params.OverrideBeaconNetworkConfig(c)
-	_, err := e.EncodeWithMaxLength(buf, st.InnerStateUnsafe())
+	_, err := e.EncodeWithMaxLength(buf, st.InnerStateUnsafe().(*ethpb.BeaconState))
 	require.NoError(t, err)
 	// Max snappy block size
 	if buf.Len() <= 76490 {
 		t.Errorf("buffer smaller than expected, wanted > %d but got %d", 76490, buf.Len())
 	}
-	decoded := new(statepb.BeaconState)
+	decoded := new(ethpb.BeaconState)
 	err = e.DecodeWithMaxLength(buf, decoded)
 	assert.NoError(t, err)
 }
@@ -144,7 +144,7 @@ func TestSszNetworkEncoder_MaxInt64(t *testing.T) {
 func TestSszNetworkEncoder_DecodeWithBadSnappyStream(t *testing.T) {
 	st := newBadSnappyStream()
 	e := &encoder.SszNetworkEncoder{}
-	decoded := new(statepb.Fork)
+	decoded := new(ethpb.Fork)
 	err := e.DecodeWithMaxLength(st, decoded)
 	assert.ErrorContains(t, io.EOF.Error(), err)
 }

beacon-chain/p2p/fork.go

@@ -3,11 +3,11 @@ package p2p
 import (
 	"bytes"
 	"fmt"
-	"math"
 	"time"
 
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
+	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	pb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/p2putils"
@@ -20,16 +20,12 @@ import (
 var eth2ENRKey = params.BeaconNetworkConfig().ETH2Key
 
 // ForkDigest returns the current fork digest of
-// the node.
-func (s *Service) forkDigest() ([4]byte, error) {
-	if s.currentForkDigest != [4]byte{} {
-		return s.currentForkDigest, nil
+// the node according to the local clock.
+func (s *Service) currentForkDigest() ([4]byte, error) {
+	if !s.isInitialized() {
+		return [4]byte{}, errors.New("state is not initialized")
 	}
-	fd, err := p2putils.CreateForkDigest(s.genesisTime, s.genesisValidatorsRoot)
-	if err != nil {
-		s.currentForkDigest = fd
-	}
-	return fd, err
+	return p2putils.CreateForkDigest(s.genesisTime, s.genesisValidatorsRoot)
 }
 
 // Compares fork ENRs between an incoming peer's record and our node's
@@ -97,20 +93,10 @@ func addForkEntry(
 	if timeutils.Now().Before(genesisTime) {
 		currentEpoch = 0
 	}
-	fork, err := p2putils.Fork(currentEpoch)
-	if err != nil {
-		return nil, err
-	}
-
-	nextForkEpoch := params.BeaconConfig().NextForkEpoch
-	nextForkVersion := params.BeaconConfig().NextForkVersion
-	// Set to the current fork version if our next fork is not planned.
-	if nextForkEpoch == math.MaxUint64 {
-		nextForkVersion = fork.CurrentVersion
-	}
+	nextForkVersion, nextForkEpoch := p2putils.NextForkData(currentEpoch)
 	enrForkID := &pb.ENRForkID{
 		CurrentForkDigest: digest[:],
-		NextForkVersion:   nextForkVersion,
+		NextForkVersion:   nextForkVersion[:],
 		NextForkEpoch:     nextForkEpoch,
 	}
 	enc, err := enrForkID.MarshalSSZ()

beacon-chain/p2p/fork_test.go

@@ -144,7 +144,7 @@ func TestStartDiscv5_SameForkDigests_DifferentNextForkData(t *testing.T) {
 
 		c := params.BeaconConfig()
 		nextForkEpoch := types.Epoch(i)
-		c.NextForkEpoch = nextForkEpoch
+		c.ForkVersionSchedule[[4]byte{'A', 'B', 'C', 'D'}] = nextForkEpoch
 		params.OverrideBeaconConfig(c)
 
 		// We give every peer a different genesis validators root, which
@@ -209,14 +209,12 @@ func TestStartDiscv5_SameForkDigests_DifferentNextForkData(t *testing.T) {
 func TestDiscv5_AddRetrieveForkEntryENR(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	c := params.BeaconConfig()
-	c.ForkVersionSchedule = map[types.Epoch][]byte{
-		0: params.BeaconConfig().GenesisForkVersion,
-		1: {0, 0, 0, 1},
+	c.ForkVersionSchedule = map[[4]byte]types.Epoch{
+		bytesutil.ToBytes4(params.BeaconConfig().GenesisForkVersion): 0,
+		{0, 0, 0, 1}: 1,
 	}
 	nextForkEpoch := types.Epoch(1)
 	nextForkVersion := []byte{0, 0, 0, 1}
-	c.NextForkEpoch = nextForkEpoch
-	c.NextForkVersion = nextForkVersion
 	params.OverrideBeaconConfig(c)
 
 	genesisTime := time.Now()
@@ -255,6 +253,7 @@ func TestDiscv5_AddRetrieveForkEntryENR(t *testing.T) {
 }
 
 func TestAddForkEntry_Genesis(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
 	temp := t.TempDir()
 	randNum := rand.Int()
 	tempPath := path.Join(temp, strconv.Itoa(randNum))
@@ -264,6 +263,11 @@ func TestAddForkEntry_Genesis(t *testing.T) {
 	db, err := enode.OpenDB("")
 	require.NoError(t, err)
 
+	bCfg := params.BeaconConfig()
+	bCfg.ForkVersionSchedule = map[[4]byte]types.Epoch{}
+	bCfg.ForkVersionSchedule[bytesutil.ToBytes4(params.BeaconConfig().GenesisForkVersion)] = bCfg.GenesisEpoch
+	params.OverrideBeaconConfig(bCfg)
+
 	localNode := enode.NewLocalNode(db, pkey)
 	localNode, err = addForkEntry(localNode, time.Now().Add(10*time.Second), bytesutil.PadTo([]byte{'A', 'B', 'C', 'D'}, 32))
 	require.NoError(t, err)

beacon-chain/p2p/fork_watcher.go

@@ -0,0 +1,30 @@
+package p2p
+
+import (
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/slotutil"
+)
+
+// A background routine which listens for new and upcoming forks and
+// updates the node's discovery service to reflect any new fork version
+// changes.
+func (s *Service) forkWatcher() {
+	slotTicker := slotutil.NewSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
+	for {
+		select {
+		case currSlot := <-slotTicker.C():
+			currEpoch := helpers.SlotToEpoch(currSlot)
+			if currEpoch == params.BeaconConfig().AltairForkEpoch {
+				_, err := addForkEntry(s.dv5Listener.LocalNode(), s.genesisTime, s.genesisValidatorsRoot)
+				if err != nil {
+					log.WithError(err).Error("Could not add fork entry")
+				}
+			}
+		case <-s.ctx.Done():
+			log.Debug("Context closed, exiting goroutine")
+			slotTicker.Done()
+			return
+		}
+	}
+}

beacon-chain/p2p/gossip_scoring_params.go

@@ -21,9 +21,15 @@ const (
 	// aggregateWeight specifies the scoring weight that we apply to
 	// our aggregate topic.
 	aggregateWeight = 0.5
+	// syncContributionWeight specifies the scoring weight that we apply to
+	// our sync contribution topic.
+	syncContributionWeight = 0.2
 	// attestationTotalWeight specifies the scoring weight that we apply to
 	// our attestation subnet topic.
 	attestationTotalWeight = 1
+	// syncCommitteesTotalWeight specifies the scoring weight that we apply to
+	// our sync subnet topic.
+	syncCommitteesTotalWeight = 0.4
 	// attesterSlashingWeight specifies the scoring weight that we apply to
 	// our attester slashing topic.
 	attesterSlashingWeight = 0.05
@@ -92,6 +98,10 @@ func (s *Service) topicScoreParams(topic string) (*pubsub.TopicScoreParams, erro
 		return defaultAggregateTopicParams(activeValidators)
 	case strings.Contains(topic, "beacon_attestation"):
 		return defaultAggregateSubnetTopicParams(activeValidators)
+	case strings.Contains(topic, GossipSyncCommitteeMessage):
+		return defaultSyncSubnetTopicParams(activeValidators)
+	case strings.Contains(topic, "sync_committee_contribution_and_proof"):
+		return defaultSyncContributionTopicParams()
 	case strings.Contains(topic, "voluntary_exit"):
 		return defaultVoluntaryExitTopicParams(), nil
 	case strings.Contains(topic, "proposer_slashing"):
@@ -215,6 +225,48 @@ func defaultAggregateTopicParams(activeValidators uint64) (*pubsub.TopicScorePar
 	}, nil
 }
 
+func defaultSyncContributionTopicParams() (*pubsub.TopicScoreParams, error) {
+	// Determine the expected message rate for the particular gossip topic.
+	aggPerSlot := params.BeaconConfig().SyncCommitteeSubnetCount * params.BeaconConfig().TargetAggregatorsPerSyncSubcommittee
+	firstMessageCap, err := decayLimit(scoreDecay(1*oneEpochDuration()), float64(aggPerSlot*2/gossipSubD))
+	if err != nil {
+		log.Warnf("skipping initializing topic scoring: %v", err)
+		return nil, nil
+	}
+	firstMessageWeight := maxFirstDeliveryScore / firstMessageCap
+	meshThreshold, err := decayThreshold(scoreDecay(1*oneEpochDuration()), float64(aggPerSlot)/dampeningFactor)
+	if err != nil {
+		log.Warnf("skipping initializing topic scoring: %v", err)
+		return nil, nil
+	}
+	meshWeight := -scoreByWeight(syncContributionWeight, meshThreshold)
+	meshCap := 4 * meshThreshold
+	if !meshDeliveryIsScored {
+		// Set the mesh weight as zero as a temporary measure, so as to prevent
+		// the average nodes from being penalised.
+		meshWeight = 0
+	}
+	return &pubsub.TopicScoreParams{
+		TopicWeight:                     syncContributionWeight,
+		TimeInMeshWeight:                maxInMeshScore / inMeshCap(),
+		TimeInMeshQuantum:               inMeshTime(),
+		TimeInMeshCap:                   inMeshCap(),
+		FirstMessageDeliveriesWeight:    firstMessageWeight,
+		FirstMessageDeliveriesDecay:     scoreDecay(1 * oneEpochDuration()),
+		FirstMessageDeliveriesCap:       firstMessageCap,
+		MeshMessageDeliveriesWeight:     meshWeight,
+		MeshMessageDeliveriesDecay:      scoreDecay(1 * oneEpochDuration()),
+		MeshMessageDeliveriesCap:        meshCap,
+		MeshMessageDeliveriesThreshold:  meshThreshold,
+		MeshMessageDeliveriesWindow:     2 * time.Second,
+		MeshMessageDeliveriesActivation: 1 * oneEpochDuration(),
+		MeshFailurePenaltyWeight:        meshWeight,
+		MeshFailurePenaltyDecay:         scoreDecay(1 * oneEpochDuration()),
+		InvalidMessageDeliveriesWeight:  -maxScore() / syncContributionWeight,
+		InvalidMessageDeliveriesDecay:   scoreDecay(50 * oneEpochDuration()),
+	}, nil
+}
+
 func defaultAggregateSubnetTopicParams(activeValidators uint64) (*pubsub.TopicScoreParams, error) {
 	subnetCount := params.BeaconNetworkConfig().AttestationSubnetCount
 	// Get weight for each specific subnet.
@@ -238,8 +290,13 @@ func defaultAggregateSubnetTopicParams(activeValidators uint64) (*pubsub.TopicSc
 		firstDecay = 4
 		meshDecay = 16
 	}
+	rate := numPerSlot * 2 / gossipSubD
+	if rate == 0 {
+		log.Warn("rate is 0, skipping initializing topic scoring")
+		return nil, nil
+	}
 	// Determine expected first deliveries based on the message rate.
-	firstMessageCap, err := decayLimit(scoreDecay(firstDecay*oneEpochDuration()), float64(numPerSlot*2/gossipSubD))
+	firstMessageCap, err := decayLimit(scoreDecay(firstDecay*oneEpochDuration()), float64(rate))
 	if err != nil {
 		log.Warnf("skipping initializing topic scoring: %v", err)
 		return nil, nil
@@ -279,6 +336,69 @@ func defaultAggregateSubnetTopicParams(activeValidators uint64) (*pubsub.TopicSc
 	}, nil
 }
 
+func defaultSyncSubnetTopicParams(activeValidators uint64) (*pubsub.TopicScoreParams, error) {
+	subnetCount := params.BeaconConfig().SyncCommitteeSubnetCount
+	// Get weight for each specific subnet.
+	topicWeight := syncCommitteesTotalWeight / float64(subnetCount)
+	syncComSize := params.BeaconConfig().SyncCommitteeSize
+	// Set the max as the sync committee size
+	if activeValidators > syncComSize {
+		activeValidators = syncComSize
+	}
+	subnetWeight := activeValidators / subnetCount
+	if subnetWeight == 0 {
+		log.Warn("Subnet weight is 0, skipping initializing topic scoring")
+		return nil, nil
+	}
+	firstDecay := time.Duration(1)
+	meshDecay := time.Duration(4)
+
+	rate := subnetWeight * 2 / gossipSubD
+	if rate == 0 {
+		log.Warn("rate is 0, skipping initializing topic scoring")
+		return nil, nil
+	}
+	// Determine expected first deliveries based on the message rate.
+	firstMessageCap, err := decayLimit(scoreDecay(firstDecay*oneEpochDuration()), float64(rate))
+	if err != nil {
+		log.Warnf("skipping initializing topic scoring: %v", err)
+		return nil, nil
+	}
+	firstMessageWeight := maxFirstDeliveryScore / firstMessageCap
+	// Determine expected mesh deliveries based on message rate applied with a dampening factor.
+	meshThreshold, err := decayThreshold(scoreDecay(meshDecay*oneEpochDuration()), float64(subnetWeight)/dampeningFactor)
+	if err != nil {
+		log.Warnf("skipping initializing topic scoring: %v", err)
+		return nil, nil
+	}
+	meshWeight := -scoreByWeight(topicWeight, meshThreshold)
+	meshCap := 4 * meshThreshold
+	if !meshDeliveryIsScored {
+		// Set the mesh weight as zero as a temporary measure, so as to prevent
+		// the average nodes from being penalised.
+		meshWeight = 0
+	}
+	return &pubsub.TopicScoreParams{
+		TopicWeight:                     topicWeight,
+		TimeInMeshWeight:                maxInMeshScore / inMeshCap(),
+		TimeInMeshQuantum:               inMeshTime(),
+		TimeInMeshCap:                   inMeshCap(),
+		FirstMessageDeliveriesWeight:    firstMessageWeight,
+		FirstMessageDeliveriesDecay:     scoreDecay(firstDecay * oneEpochDuration()),
+		FirstMessageDeliveriesCap:       firstMessageCap,
+		MeshMessageDeliveriesWeight:     meshWeight,
+		MeshMessageDeliveriesDecay:      scoreDecay(meshDecay * oneEpochDuration()),
+		MeshMessageDeliveriesCap:        meshCap,
+		MeshMessageDeliveriesThreshold:  meshThreshold,
+		MeshMessageDeliveriesWindow:     2 * time.Second,
+		MeshMessageDeliveriesActivation: 1 * oneEpochDuration(),
+		MeshFailurePenaltyWeight:        meshWeight,
+		MeshFailurePenaltyDecay:         scoreDecay(meshDecay * oneEpochDuration()),
+		InvalidMessageDeliveriesWeight:  -maxScore() / topicWeight,
+		InvalidMessageDeliveriesDecay:   scoreDecay(50 * oneEpochDuration()),
+	}, nil
+}
+
 func defaultAttesterSlashingTopicParams() *pubsub.TopicScoreParams {
 	return &pubsub.TopicScoreParams{
 		TopicWeight:                     attesterSlashingWeight,
@@ -401,8 +521,9 @@ func scoreByWeight(weight, threshold float64) float64 {
 
 // maxScore attainable by a peer.
 func maxScore() float64 {
-	totalWeight := beaconBlockWeight + aggregateWeight + attestationTotalWeight +
-		attesterSlashingWeight + proposerSlashingWeight + voluntaryExitWeight
+	totalWeight := beaconBlockWeight + aggregateWeight + +syncContributionWeight +
+		attestationTotalWeight + syncCommitteesTotalWeight + attesterSlashingWeight +
+		proposerSlashingWeight + voluntaryExitWeight
 	return (maxInMeshScore + maxFirstDeliveryScore) * totalWeight
 }
 

beacon-chain/p2p/gossip_topic_mappings.go

@@ -3,27 +3,53 @@ package p2p
 import (
 	"reflect"
 
+	types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	pb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/params"
 	"google.golang.org/protobuf/proto"
 )
 
-// GossipTopicMappings represent the protocol ID to protobuf message type map for easy
+// gossipTopicMappings represent the protocol ID to protobuf message type map for easy
 // lookup.
-var GossipTopicMappings = map[string]proto.Message{
-	BlockSubnetTopicFormat:             &pb.SignedBeaconBlock{},
-	AttestationSubnetTopicFormat:       &pb.Attestation{},
-	ExitSubnetTopicFormat:              &pb.SignedVoluntaryExit{},
-	ProposerSlashingSubnetTopicFormat:  &pb.ProposerSlashing{},
-	AttesterSlashingSubnetTopicFormat:  &pb.AttesterSlashing{},
-	AggregateAndProofSubnetTopicFormat: &pb.SignedAggregateAttestationAndProof{},
+var gossipTopicMappings = map[string]proto.Message{
+	BlockSubnetTopicFormat:                    &pb.SignedBeaconBlock{},
+	AttestationSubnetTopicFormat:              &pb.Attestation{},
+	ExitSubnetTopicFormat:                     &pb.SignedVoluntaryExit{},
+	ProposerSlashingSubnetTopicFormat:         &pb.ProposerSlashing{},
+	AttesterSlashingSubnetTopicFormat:         &pb.AttesterSlashing{},
+	AggregateAndProofSubnetTopicFormat:        &pb.SignedAggregateAttestationAndProof{},
+	SyncContributionAndProofSubnetTopicFormat: &ethpb.SignedContributionAndProof{},
+	SyncCommitteeSubnetTopicFormat:            &ethpb.SyncCommitteeMessage{},
+}
+
+// GossipTopicMappings is a function to return the assigned data type
+// versioned by epoch.
+func GossipTopicMappings(topic string, epoch types.Epoch) proto.Message {
+	if topic == BlockSubnetTopicFormat && epoch >= params.BeaconConfig().AltairForkEpoch {
+		return &ethpb.SignedBeaconBlockAltair{}
+	}
+	return gossipTopicMappings[topic]
+}
+
+// AllTopics returns all topics stored in our
+// gossip mapping.
+func AllTopics() []string {
+	topics := []string{}
+	for k := range gossipTopicMappings {
+		topics = append(topics, k)
+	}
+	return topics
 }
 
 // GossipTypeMapping is the inverse of GossipTopicMappings so that an arbitrary protobuf message
 // can be mapped to a protocol ID string.
-var GossipTypeMapping = make(map[reflect.Type]string, len(GossipTopicMappings))
+var GossipTypeMapping = make(map[reflect.Type]string, len(gossipTopicMappings))
 
 func init() {
-	for k, v := range GossipTopicMappings {
+	for k, v := range gossipTopicMappings {
 		GossipTypeMapping[reflect.TypeOf(v)] = k
 	}
+	// Specially handle Altair Objects.
+	GossipTypeMapping[reflect.TypeOf(&ethpb.SignedBeaconBlockAltair{})] = BlockSubnetTopicFormat
 }

beacon-chain/p2p/gossip_topic_mappings_test.go

@@ -3,14 +3,39 @@ package p2p
 import (
 	"reflect"
 	"testing"
+
+	eth2types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 )
 
 func TestMappingHasNoDuplicates(t *testing.T) {
 	m := make(map[reflect.Type]bool)
-	for _, v := range GossipTopicMappings {
+	for _, v := range gossipTopicMappings {
 		if _, ok := m[reflect.TypeOf(v)]; ok {
 			t.Errorf("%T is duplicated in the topic mapping", v)
 		}
 		m[reflect.TypeOf(v)] = true
 	}
 }
+
+func TestGossipTopicMappings_CorrectBlockType(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	bCfg := params.BeaconConfig()
+	forkEpoch := eth2types.Epoch(100)
+	bCfg.AltairForkEpoch = forkEpoch
+	bCfg.ForkVersionSchedule[bytesutil.ToBytes4(bCfg.AltairForkVersion)] = eth2types.Epoch(100)
+	params.OverrideBeaconConfig(bCfg)
+
+	// Before Fork
+	pMessage := GossipTopicMappings(BlockSubnetTopicFormat, 0)
+	_, ok := pMessage.(*ethpb.SignedBeaconBlock)
+	assert.Equal(t, true, ok)
+
+	// After Fork
+	pMessage = GossipTopicMappings(BlockSubnetTopicFormat, forkEpoch)
+	_, ok = pMessage.(*ethpb.SignedBeaconBlockAltair)
+	assert.Equal(t, true, ok)
+}

beacon-chain/p2p/interfaces.go

@@ -35,6 +35,7 @@ type P2P interface {
 type Broadcaster interface {
 	Broadcast(context.Context, proto.Message) error
 	BroadcastAttestation(ctx context.Context, subnet uint64, att *ethpb.Attestation) error
+	BroadcastSyncCommitteeMessage(ctx context.Context, subnet uint64, sMsg *ethpb.SyncCommitteeMessage) error
 }
 
 // SetStreamHandler configures p2p to handle streams of a certain topic ID.

beacon-chain/p2p/monitoring.go

@@ -25,6 +25,16 @@ var (
 		Name: "p2p_attestation_subnet_attempted_broadcasts",
 		Help: "The number of attestations that were attempted to be broadcast.",
 	})
+	savedSyncCommitteeBroadcasts = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "p2p_sync_committee_subnet_recovered_broadcasts",
+		Help: "The number of sync committee messages that were attempted to be broadcast with no peers on " +
+			"the subnet. The beacon node increments this counter when the broadcast is blocked " +
+			"until a subnet peer can be found.",
+	})
+	syncCommitteeBroadcastAttempts = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "p2p_sync_committee_subnet_attempted_broadcasts",
+		Help: "The number of sync committee that were attempted to be broadcast.",
+	})
 )
 
 func (s *Service) updateMetrics() {

beacon-chain/p2p/peers/status.go

@@ -235,7 +235,7 @@ func (p *Status) SetMetadata(pid peer.ID, metaData metadata.Metadata) {
 	defer p.store.Unlock()
 
 	peerData := p.store.PeerDataGetOrCreate(pid)
-	peerData.MetaData = metaData
+	peerData.MetaData = metaData.Copy()
 }
 
 // Metadata returns a copy of the metadata corresponding to the provided

beacon-chain/p2p/pubsub.go

@@ -2,16 +2,21 @@ package p2p
 
 import (
 	"context"
+	"encoding/hex"
+	"strings"
 	"time"
 
 	"github.com/libp2p/go-libp2p-core/peer"
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	pubsub_pb "github.com/libp2p/go-libp2p-pubsub/pb"
+	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/encoder"
 	"github.com/prysmaticlabs/prysm/cmd/beacon-chain/flags"
 	pbrpc "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
+	"github.com/prysmaticlabs/prysm/shared/p2putils"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
 
@@ -36,6 +41,11 @@ const (
 	randomSubD = 6 // random gossip target
 )
 
+var errInvalidTopic = errors.New("invalid topic format")
+
+// Specifies the fixed size context length.
+const digestLength = 4
+
 // JoinTopic will join PubSub topic, if not already joined.
 func (s *Service) JoinTopic(topic string, opts ...pubsub.TopicOpt) (*pubsub.Topic, error) {
 	s.joinedTopicsLock.Lock()
@@ -132,7 +142,26 @@ func (s *Service) peerInspector(peerMap map[peer.ID]*pubsub.PeerScoreSnapshot) {
 //    Otherwise, set `message-id` to the first 20 bytes of the `SHA256` hash of
 //    the concatenation of `MESSAGE_DOMAIN_INVALID_SNAPPY` with the raw message data,
 //    i.e. `SHA256(MESSAGE_DOMAIN_INVALID_SNAPPY + message.data)[:20]`.
-func msgIDFunction(pmsg *pubsub_pb.Message) string {
+func (s *Service) msgIDFunction(pmsg *pubsub_pb.Message) string {
+	digest, err := ExtractGossipDigest(*pmsg.Topic)
+	if err != nil {
+		// Impossible condition that should
+		// never be hit.
+		msg := make([]byte, 20)
+		copy(msg, "invalid")
+		return string(msg)
+	}
+	_, fEpoch, err := p2putils.RetrieveForkDataFromDigest(digest, s.genesisValidatorsRoot)
+	if err != nil {
+		// Impossible condition that should
+		// never be hit.
+		msg := make([]byte, 20)
+		copy(msg, "invalid")
+		return string(msg)
+	}
+	if fEpoch >= params.BeaconConfig().AltairForkEpoch {
+		return s.altairMsgID(pmsg)
+	}
 	decodedData, err := encoder.DecodeSnappy(pmsg.Data, params.BeaconNetworkConfig().GossipMaxSize)
 	if err != nil {
 		combinedData := append(params.BeaconNetworkConfig().MessageDomainInvalidSnappy[:], pmsg.Data...)
@@ -144,6 +173,43 @@ func msgIDFunction(pmsg *pubsub_pb.Message) string {
 	return string(h[:20])
 }
 
+// Spec:
+// The derivation of the message-id has changed starting with Altair to incorporate the message topic along with the message data.
+// These are fields of the Message Protobuf, and interpreted as empty byte strings if missing. The message-id MUST be the following
+// 20 byte value computed from the message:
+//
+// If message.data has a valid snappy decompression, set message-id to the first 20 bytes of the SHA256 hash of the concatenation of
+// the following data: MESSAGE_DOMAIN_VALID_SNAPPY, the length of the topic byte string (encoded as little-endian uint64), the topic
+// byte string, and the snappy decompressed message data: i.e. SHA256(MESSAGE_DOMAIN_VALID_SNAPPY + uint_to_bytes(uint64(len(message.topic)))
+// + message.topic + snappy_decompress(message.data))[:20]. Otherwise, set message-id to the first 20 bytes of the SHA256 hash of the concatenation
+// of the following data: MESSAGE_DOMAIN_INVALID_SNAPPY, the length of the topic byte string (encoded as little-endian uint64),
+// the topic byte string, and the raw message data: i.e. SHA256(MESSAGE_DOMAIN_INVALID_SNAPPY + uint_to_bytes(uint64(len(message.topic))) + message.topic + message.data)[:20].
+func (s *Service) altairMsgID(pmsg *pubsub_pb.Message) string {
+	topic := *pmsg.Topic
+	topicLen := uint64(len(topic))
+	topicLenBytes := bytesutil.Uint64ToBytesLittleEndian(topicLen)
+
+	decodedData, err := encoder.DecodeSnappy(pmsg.Data, params.BeaconNetworkConfig().GossipMaxSize)
+	if err != nil {
+		totalLength := len(params.BeaconNetworkConfig().MessageDomainInvalidSnappy) + len(topicLenBytes) + int(topicLen) + len(pmsg.Data)
+		combinedData := make([]byte, 0, totalLength)
+		combinedData = append(combinedData, params.BeaconNetworkConfig().MessageDomainInvalidSnappy[:]...)
+		combinedData = append(combinedData, topicLenBytes...)
+		combinedData = append(combinedData, topic...)
+		combinedData = append(combinedData, pmsg.Data...)
+		h := hashutil.Hash(combinedData)
+		return string(h[:20])
+	}
+	totalLength := len(params.BeaconNetworkConfig().MessageDomainValidSnappy) + len(topicLenBytes) + int(topicLen) + len(decodedData)
+	combinedData := make([]byte, 0, totalLength)
+	combinedData = append(combinedData, params.BeaconNetworkConfig().MessageDomainValidSnappy[:]...)
+	combinedData = append(combinedData, topicLenBytes...)
+	combinedData = append(combinedData, topic...)
+	combinedData = append(combinedData, decodedData...)
+	h := hashutil.Hash(combinedData)
+	return string(h[:20])
+}
+
 // creates a custom gossipsub parameter set.
 func pubsubGossipParam() pubsub.GossipSubParams {
 	gParams := pubsub.DefaultGossipSubParams()
@@ -184,3 +250,27 @@ func convertTopicScores(topicMap map[string]*pubsub.TopicScoreSnapshot) map[stri
 	}
 	return newMap
 }
+
+// Extracts the relevant fork digest from the gossip topic.
+func ExtractGossipDigest(topic string) ([4]byte, error) {
+	splitParts := strings.Split(topic, "/")
+	parts := []string{}
+	for _, p := range splitParts {
+		if p == "" {
+			continue
+		}
+		parts = append(parts, p)
+	}
+	if len(parts) < 2 {
+		return [4]byte{}, errors.Wrapf(errInvalidTopic, "it only has %d parts: %v", len(parts), parts)
+	}
+	strDigest := parts[1]
+	digest, err := hex.DecodeString(strDigest)
+	if err != nil {
+		return [4]byte{}, err
+	}
+	if len(digest) != digestLength {
+		return [4]byte{}, errors.Errorf("invalid digest length wanted %d but got %d", digestLength, len(digest))
+	}
+	return bytesutil.ToBytes4(digest), nil
+}

beacon-chain/p2p/pubsub_filter.go

@@ -8,11 +8,18 @@ import (
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	pubsubpb "github.com/libp2p/go-libp2p-pubsub/pb"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/encoder"
+	"github.com/prysmaticlabs/prysm/shared/p2putils"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )
 
 var _ pubsub.SubscriptionFilter = (*Service)(nil)
 
-const pubsubSubscriptionRequestLimit = 100
+// It is set at this limit to handle the possibility
+// of double topic subscriptions at fork boundaries.
+// -> 64 Attestation Subnets * 2.
+// -> 4 Sync Committee Subnets * 2.
+// -> Block,Aggregate,ProposerSlashing,AttesterSlashing,Exits,SyncContribution * 2.
+const pubsubSubscriptionRequestLimit = 200
 
 // CanSubscribe returns true if the topic is of interest and we could subscribe to it.
 func (s *Service) CanSubscribe(topic string) bool {
@@ -30,12 +37,17 @@ func (s *Service) CanSubscribe(topic string) bool {
 	if parts[1] != "eth2" {
 		return false
 	}
-	fd, err := s.forkDigest()
+	fd, err := s.currentForkDigest()
 	if err != nil {
 		log.WithError(err).Error("Could not determine fork digest")
 		return false
 	}
-	if parts[2] != fmt.Sprintf("%x", fd) {
+	digest, err := p2putils.ForkDigestFromEpoch(params.BeaconConfig().AltairForkEpoch, s.genesisValidatorsRoot)
+	if err != nil {
+		log.WithError(err).Error("Could not determine next fork digest")
+		return false
+	}
+	if parts[2] != fmt.Sprintf("%x", fd) && parts[2] != fmt.Sprintf("%x", digest) {
 		return false
 	}
 	if parts[4] != encoder.ProtocolSuffixSSZSnappy {
@@ -43,7 +55,7 @@ func (s *Service) CanSubscribe(topic string) bool {
 	}
 
 	// Check the incoming topic matches any topic mapping. This includes a check for part[3].
-	for gt := range GossipTopicMappings {
+	for gt := range gossipTopicMappings {
 		if _, err := scanfcheck(strings.Join(parts[0:4], "/"), gt); err == nil {
 			return true
 		}

beacon-chain/p2p/pubsub_filter_test.go

@@ -14,7 +14,8 @@ import (
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/encoder"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
-	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/p2putils"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/timeutils"
 	"github.com/stretchr/testify/require"
 )
@@ -22,6 +23,10 @@ import (
 func TestService_CanSubscribe(t *testing.T) {
 	currentFork := [4]byte{0x01, 0x02, 0x03, 0x04}
 	validProtocolSuffix := "/" + encoder.ProtocolSuffixSSZSnappy
+	genesisTime := time.Now()
+	valRoot := [32]byte{}
+	digest, err := p2putils.CreateForkDigest(genesisTime, valRoot[:])
+	assert.NoError(t, err)
 	type test struct {
 		name  string
 		topic string
@@ -30,7 +35,7 @@ func TestService_CanSubscribe(t *testing.T) {
 	tests := []test{
 		{
 			name:  "block topic on current fork",
-			topic: fmt.Sprintf(BlockSubnetTopicFormat, currentFork) + validProtocolSuffix,
+			topic: fmt.Sprintf(BlockSubnetTopicFormat, digest) + validProtocolSuffix,
 			want:  true,
 		},
 		{
@@ -60,17 +65,17 @@ func TestService_CanSubscribe(t *testing.T) {
 		},
 		{
 			name:  "bad prefix",
-			topic: fmt.Sprintf("/eth3/%x/foobar", currentFork) + validProtocolSuffix,
+			topic: fmt.Sprintf("/eth3/%x/foobar", digest) + validProtocolSuffix,
 			want:  false,
 		},
 		{
 			name:  "topic not in gossip mapping",
-			topic: fmt.Sprintf("/eth2/%x/foobar", currentFork) + validProtocolSuffix,
+			topic: fmt.Sprintf("/eth2/%x/foobar", digest) + validProtocolSuffix,
 			want:  false,
 		},
 		{
 			name:  "att subnet topic on current fork",
-			topic: fmt.Sprintf(AttestationSubnetTopicFormat, currentFork, 55 /*subnet*/) + validProtocolSuffix,
+			topic: fmt.Sprintf(AttestationSubnetTopicFormat, digest, 55 /*subnet*/) + validProtocolSuffix,
 			want:  true,
 		},
 		{
@@ -81,11 +86,11 @@ func TestService_CanSubscribe(t *testing.T) {
 	}
 
 	// Ensure all gossip topic mappings pass validation.
-	for topic := range GossipTopicMappings {
-		formatting := []interface{}{currentFork}
+	for _, topic := range AllTopics() {
+		formatting := []interface{}{digest}
 
 		// Special case for attestation subnets which have a second formatting placeholder.
-		if topic == AttestationSubnetTopicFormat {
+		if topic == AttestationSubnetTopicFormat || topic == SyncCommitteeSubnetTopicFormat {
 			formatting = append(formatting, 0 /* some subnet ID */)
 		}
 
@@ -99,9 +104,8 @@ func TestService_CanSubscribe(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			s := &Service{
-				currentForkDigest:     currentFork,
-				genesisValidatorsRoot: make([]byte, 32),
-				genesisTime:           time.Now(),
+				genesisValidatorsRoot: valRoot[:],
+				genesisTime:           genesisTime,
 			}
 			if got := s.CanSubscribe(tt.topic); got != tt.want {
 				t.Errorf("CanSubscribe(%s) = %v, want %v", tt.topic, got, tt.want)
@@ -189,7 +193,7 @@ func Test_scanfcheck(t *testing.T) {
 func TestGossipTopicMapping_scanfcheck_GossipTopicFormattingSanityCheck(t *testing.T) {
 	// scanfcheck only supports integer based substitutions at the moment. Any others will
 	// inaccurately fail validation.
-	for topic := range GossipTopicMappings {
+	for _, topic := range AllTopics() {
 		t.Run(topic, func(t *testing.T) {
 			for i, c := range topic {
 				if string(c) == "%" {
@@ -204,8 +208,11 @@ func TestGossipTopicMapping_scanfcheck_GossipTopicFormattingSanityCheck(t *testi
 }
 
 func TestService_FilterIncomingSubscriptions(t *testing.T) {
-	currentFork := [4]byte{0x01, 0x02, 0x03, 0x04}
 	validProtocolSuffix := "/" + encoder.ProtocolSuffixSSZSnappy
+	genesisTime := time.Now()
+	valRoot := [32]byte{}
+	digest, err := p2putils.CreateForkDigest(genesisTime, valRoot[:])
+	assert.NoError(t, err)
 	type args struct {
 		id   peer.ID
 		subs []*pubsubpb.RPC_SubOpts
@@ -241,7 +248,7 @@ func TestService_FilterIncomingSubscriptions(t *testing.T) {
 							return &b
 						}(),
 						Topicid: func() *string {
-							s := fmt.Sprintf(BlockSubnetTopicFormat, currentFork) + validProtocolSuffix
+							s := fmt.Sprintf(BlockSubnetTopicFormat, digest) + validProtocolSuffix
 							return &s
 						}(),
 					},
@@ -255,7 +262,7 @@ func TestService_FilterIncomingSubscriptions(t *testing.T) {
 						return &b
 					}(),
 					Topicid: func() *string {
-						s := fmt.Sprintf(BlockSubnetTopicFormat, currentFork) + validProtocolSuffix
+						s := fmt.Sprintf(BlockSubnetTopicFormat, digest) + validProtocolSuffix
 						return &s
 					}(),
 				},
@@ -271,7 +278,7 @@ func TestService_FilterIncomingSubscriptions(t *testing.T) {
 							return &b
 						}(),
 						Topicid: func() *string {
-							s := fmt.Sprintf(BlockSubnetTopicFormat, currentFork) + validProtocolSuffix
+							s := fmt.Sprintf(BlockSubnetTopicFormat, digest) + validProtocolSuffix
 							return &s
 						}(),
 					},
@@ -281,7 +288,7 @@ func TestService_FilterIncomingSubscriptions(t *testing.T) {
 							return &b
 						}(),
 						Topicid: func() *string {
-							s := fmt.Sprintf(BlockSubnetTopicFormat, currentFork) + validProtocolSuffix
+							s := fmt.Sprintf(BlockSubnetTopicFormat, digest) + validProtocolSuffix
 							return &s
 						}(),
 					},
@@ -295,7 +302,7 @@ func TestService_FilterIncomingSubscriptions(t *testing.T) {
 						return &b
 					}(),
 					Topicid: func() *string {
-						s := fmt.Sprintf(BlockSubnetTopicFormat, currentFork) + validProtocolSuffix
+						s := fmt.Sprintf(BlockSubnetTopicFormat, digest) + validProtocolSuffix
 						return &s
 					}(),
 				},
@@ -305,9 +312,8 @@ func TestService_FilterIncomingSubscriptions(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			s := &Service{
-				currentForkDigest:     currentFork,
-				genesisValidatorsRoot: make([]byte, 32),
-				genesisTime:           time.Now(),
+				genesisValidatorsRoot: valRoot[:],
+				genesisTime:           genesisTime,
 			}
 			got, err := s.FilterIncomingSubscriptions(tt.args.id, tt.args.subs)
 			if (err != nil) != tt.wantErr {
@@ -350,14 +356,4 @@ func TestService_MonitorsStateForkUpdates(t *testing.T) {
 	time.Sleep(50 * time.Millisecond)
 
 	require.True(t, s.isInitialized())
-	require.NotEmpty(t, s.currentForkDigest)
-}
-
-func TestService_doesntSupportForksYet(t *testing.T) {
-	// Part of phase 1 will include a state transition which updates the state's fork. In phase 0,
-	// there are no forks or fork schedule planned. As such, we'll work on supporting fork upgrades
-	// in phase 1 changes.
-	if len(params.BeaconConfig().ForkVersionSchedule) > 0 {
-		t.Fatal("pubsub subscription filters do not support fork schedule (yet)")
-	}
 }

beacon-chain/p2p/pubsub_test.go

@@ -9,9 +9,12 @@ import (
 
 	"github.com/golang/snappy"
 	pubsubpb "github.com/libp2p/go-libp2p-pubsub/pb"
+	"github.com/pkg/errors"
 	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/encoder"
 	testp2p "github.com/prysmaticlabs/prysm/beacon-chain/p2p/testing"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
@@ -58,16 +61,112 @@ func TestService_PublishToTopicConcurrentMapWrite(t *testing.T) {
 }
 
 func TestMessageIDFunction_HashesCorrectly(t *testing.T) {
+	s := &Service{
+		cfg: &Config{
+			TCPPort: 0,
+			UDPPort: 0,
+		},
+		genesisTime:           time.Now(),
+		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+	}
+	d, err := s.currentForkDigest()
+	assert.NoError(t, err)
+	tpc := fmt.Sprintf(BlockSubnetTopicFormat, d)
 	invalidSnappy := [32]byte{'J', 'U', 'N', 'K'}
-	pMsg := &pubsubpb.Message{Data: invalidSnappy[:]}
+	pMsg := &pubsubpb.Message{Data: invalidSnappy[:], Topic: &tpc}
 	hashedData := hashutil.Hash(append(params.BeaconNetworkConfig().MessageDomainInvalidSnappy[:], pMsg.Data...))
 	msgID := string(hashedData[:20])
-	assert.Equal(t, msgID, msgIDFunction(pMsg), "Got incorrect msg id")
+	assert.Equal(t, msgID, s.msgIDFunction(pMsg), "Got incorrect msg id")
 
 	validObj := [32]byte{'v', 'a', 'l', 'i', 'd'}
 	enc := snappy.Encode(nil, validObj[:])
-	nMsg := &pubsubpb.Message{Data: enc}
+	nMsg := &pubsubpb.Message{Data: enc, Topic: &tpc}
 	hashedData = hashutil.Hash(append(params.BeaconNetworkConfig().MessageDomainValidSnappy[:], validObj[:]...))
 	msgID = string(hashedData[:20])
-	assert.Equal(t, msgID, msgIDFunction(nMsg), "Got incorrect msg id")
+	assert.Equal(t, msgID, s.msgIDFunction(nMsg), "Got incorrect msg id")
+}
+
+func TestMessageIDFunction_HashesCorrectlyAltair(t *testing.T) {
+	s := &Service{
+		cfg: &Config{
+			TCPPort: 0,
+			UDPPort: 0,
+		},
+		genesisTime:           time.Now(),
+		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+	}
+	d, err := helpers.ComputeForkDigest(params.BeaconConfig().AltairForkVersion, s.genesisValidatorsRoot)
+	assert.NoError(t, err)
+	tpc := fmt.Sprintf(BlockSubnetTopicFormat, d)
+	topicLen := uint64(len(tpc))
+	topicLenBytes := bytesutil.Uint64ToBytesLittleEndian(topicLen)
+	invalidSnappy := [32]byte{'J', 'U', 'N', 'K'}
+	pMsg := &pubsubpb.Message{Data: invalidSnappy[:], Topic: &tpc}
+	// Create object to hash
+	combinedObj := append(params.BeaconNetworkConfig().MessageDomainInvalidSnappy[:], topicLenBytes...)
+	combinedObj = append(combinedObj, tpc...)
+	combinedObj = append(combinedObj, pMsg.Data...)
+	hashedData := hashutil.Hash(combinedObj)
+	msgID := string(hashedData[:20])
+	assert.Equal(t, msgID, s.msgIDFunction(pMsg), "Got incorrect msg id")
+
+	validObj := [32]byte{'v', 'a', 'l', 'i', 'd'}
+	enc := snappy.Encode(nil, validObj[:])
+	nMsg := &pubsubpb.Message{Data: enc, Topic: &tpc}
+	// Create object to hash
+	combinedObj = append(params.BeaconNetworkConfig().MessageDomainValidSnappy[:], topicLenBytes...)
+	combinedObj = append(combinedObj, tpc...)
+	combinedObj = append(combinedObj, validObj[:]...)
+	hashedData = hashutil.Hash(combinedObj)
+	msgID = string(hashedData[:20])
+	assert.Equal(t, msgID, s.msgIDFunction(nMsg), "Got incorrect msg id")
+}
+
+func TestExtractGossipDigest(t *testing.T) {
+	tests := []struct {
+		name    string
+		topic   string
+		want    [4]byte
+		wantErr bool
+		error   error
+	}{
+		{
+			name:    "too short topic",
+			topic:   "/eth2/",
+			want:    [4]byte{},
+			wantErr: true,
+			error:   errors.New("invalid topic format"),
+		},
+		{
+			name:    "invalid digest in topic",
+			topic:   "/eth2/zzxxyyaa/beacon_block" + "/" + encoder.ProtocolSuffixSSZSnappy,
+			want:    [4]byte{},
+			wantErr: true,
+			error:   errors.New("encoding/hex: invalid byte"),
+		},
+		{
+			name:    "short digest",
+			topic:   fmt.Sprintf(BlockSubnetTopicFormat, []byte{0xb5, 0x30, 0x3f}) + "/" + encoder.ProtocolSuffixSSZSnappy,
+			want:    [4]byte{},
+			wantErr: true,
+			error:   errors.New("invalid digest length wanted"),
+		},
+		{
+			name:    "valid topic",
+			topic:   fmt.Sprintf(BlockSubnetTopicFormat, []byte{0xb5, 0x30, 0x3f, 0x2a}) + "/" + encoder.ProtocolSuffixSSZSnappy,
+			want:    [4]byte{0xb5, 0x30, 0x3f, 0x2a},
+			wantErr: false,
+			error:   nil,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ExtractGossipDigest(tt.topic)
+			assert.Equal(t, err != nil, tt.wantErr)
+			if tt.wantErr {
+				assert.ErrorContains(t, tt.error.Error(), err)
+			}
+			assert.DeepEqual(t, tt.want, got)
+		})
+	}
 }

beacon-chain/p2p/rpc_topic_mappings.go

@@ -7,56 +7,82 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	p2ptypes "github.com/prysmaticlabs/prysm/beacon-chain/p2p/types"
 	pb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )
 
 // SchemaVersionV1 specifies the schema version for our rpc protocol ID.
 const SchemaVersionV1 = "/1"
 
+// SchemaVersionV2 specifies the next schema version for our rpc protocol ID.
+const SchemaVersionV2 = "/2"
+
 // Specifies the protocol prefix for all our Req/Resp topics.
 const protocolPrefix = "/eth2/beacon_chain/req"
 
-// Specifies the name for the status message topic.
-const statusMessageName = "/status"
+// StatusMessageName specifies the name for the status message topic.
+const StatusMessageName = "/status"
 
-// Specifies the name for the goodbye message topic.
-const goodbyeMessageName = "/goodbye"
+// GoodbyeMessageName specifies the name for the goodbye message topic.
+const GoodbyeMessageName = "/goodbye"
 
-// Specifies the name for the beacon blocks by range message topic.
-const beaconBlocksByRangeMessageName = "/beacon_blocks_by_range"
+// BeaconBlocksByRangeMessageName specifies the name for the beacon blocks by range message topic.
+const BeaconBlocksByRangeMessageName = "/beacon_blocks_by_range"
 
-// Specifies the name for the beacon blocks by root message topic.
-const beaconBlocksByRootsMessageName = "/beacon_blocks_by_root"
+// BeaconBlocksByRootsMessageName specifies the name for the beacon blocks by root message topic.
+const BeaconBlocksByRootsMessageName = "/beacon_blocks_by_root"
 
-// Specifies the name for the ping message topic.
-const pingMessageName = "/ping"
+// PingMessageName Specifies the name for the ping message topic.
+const PingMessageName = "/ping"
 
-// Specifies the name for the metadata message topic.
-const metadataMessageName = "/metadata"
+// MetadataMessageName specifies the name for the metadata message topic.
+const MetadataMessageName = "/metadata"
 
 const (
 	// V1 RPC Topics
 	// RPCStatusTopicV1 defines the v1 topic for the status rpc method.
-	RPCStatusTopicV1 = protocolPrefix + statusMessageName + SchemaVersionV1
+	RPCStatusTopicV1 = protocolPrefix + StatusMessageName + SchemaVersionV1
 	// RPCGoodByeTopicV1 defines the v1 topic for the goodbye rpc method.
-	RPCGoodByeTopicV1 = protocolPrefix + goodbyeMessageName + SchemaVersionV1
+	RPCGoodByeTopicV1 = protocolPrefix + GoodbyeMessageName + SchemaVersionV1
 	// RPCBlocksByRangeTopicV1 defines v1 the topic for the blocks by range rpc method.
-	RPCBlocksByRangeTopicV1 = protocolPrefix + beaconBlocksByRangeMessageName + SchemaVersionV1
+	RPCBlocksByRangeTopicV1 = protocolPrefix + BeaconBlocksByRangeMessageName + SchemaVersionV1
 	// RPCBlocksByRootTopicV1 defines the v1 topic for the blocks by root rpc method.
-	RPCBlocksByRootTopicV1 = protocolPrefix + beaconBlocksByRootsMessageName + SchemaVersionV1
+	RPCBlocksByRootTopicV1 = protocolPrefix + BeaconBlocksByRootsMessageName + SchemaVersionV1
 	// RPCPingTopicV1 defines the v1 topic for the ping rpc method.
-	RPCPingTopicV1 = protocolPrefix + pingMessageName + SchemaVersionV1
+	RPCPingTopicV1 = protocolPrefix + PingMessageName + SchemaVersionV1
 	// RPCMetaDataTopicV1 defines the v1 topic for the metadata rpc method.
-	RPCMetaDataTopicV1 = protocolPrefix + metadataMessageName + SchemaVersionV1
+	RPCMetaDataTopicV1 = protocolPrefix + MetadataMessageName + SchemaVersionV1
+
+	// V2 RPC Topics
+	// RPCBlocksByRangeTopicV2 defines v2 the topic for the blocks by range rpc method.
+	RPCBlocksByRangeTopicV2 = protocolPrefix + BeaconBlocksByRangeMessageName + SchemaVersionV2
+	// RPCBlocksByRootTopicV2 defines the v2 topic for the blocks by root rpc method.
+	RPCBlocksByRootTopicV2 = protocolPrefix + BeaconBlocksByRootsMessageName + SchemaVersionV2
+	// RPCMetaDataTopicV2 defines the v2 topic for the metadata rpc method.
+	RPCMetaDataTopicV2 = protocolPrefix + MetadataMessageName + SchemaVersionV2
+)
+
+// RPC errors for topic parsing.
+const (
+	invalidRPCMessageType = "provided message type doesn't have a registered mapping"
 )
 
 // RPCTopicMappings map the base message type to the rpc request.
 var RPCTopicMappings = map[string]interface{}{
-	RPCStatusTopicV1:        new(pb.Status),
-	RPCGoodByeTopicV1:       new(types.SSZUint64),
+	// RPC Status Message
+	RPCStatusTopicV1: new(pb.Status),
+	// RPC Goodbye Message
+	RPCGoodByeTopicV1: new(types.SSZUint64),
+	// RPC Block By Range Message
 	RPCBlocksByRangeTopicV1: new(pb.BeaconBlocksByRangeRequest),
-	RPCBlocksByRootTopicV1:  new(p2ptypes.BeaconBlockByRootsReq),
-	RPCPingTopicV1:          new(types.SSZUint64),
-	RPCMetaDataTopicV1:      new(interface{}),
+	RPCBlocksByRangeTopicV2: new(pb.BeaconBlocksByRangeRequest),
+	// RPC Block By Root Message
+	RPCBlocksByRootTopicV1: new(p2ptypes.BeaconBlockByRootsReq),
+	RPCBlocksByRootTopicV2: new(p2ptypes.BeaconBlockByRootsReq),
+	// RPC Ping Message
+	RPCPingTopicV1: new(types.SSZUint64),
+	// RPC Metadata Message
+	RPCMetaDataTopicV1: new(interface{}),
+	RPCMetaDataTopicV2: new(interface{}),
 }
 
 // Maps all registered protocol prefixes.
@@ -67,16 +93,24 @@ var protocolMapping = map[string]bool{
 // Maps all the protocol message names for the different rpc
 // topics.
 var messageMapping = map[string]bool{
-	statusMessageName:              true,
-	goodbyeMessageName:             true,
-	beaconBlocksByRangeMessageName: true,
-	beaconBlocksByRootsMessageName: true,
-	pingMessageName:                true,
-	metadataMessageName:            true,
+	StatusMessageName:              true,
+	GoodbyeMessageName:             true,
+	BeaconBlocksByRangeMessageName: true,
+	BeaconBlocksByRootsMessageName: true,
+	PingMessageName:                true,
+	MetadataMessageName:            true,
+}
+
+// Maps all the RPC messages which are to updated in altair.
+var altairMapping = map[string]bool{
+	BeaconBlocksByRangeMessageName: true,
+	BeaconBlocksByRootsMessageName: true,
+	MetadataMessageName:            true,
 }
 
 var versionMapping = map[string]bool{
 	SchemaVersionV1: true,
+	SchemaVersionV2: true,
 }
 
 // VerifyTopicMapping verifies that the topic and its accompanying
@@ -187,3 +221,17 @@ func (r RPCTopic) Version() string {
 	}
 	return version
 }
+
+// TopicFromMessage constructs the rpc topic from the provided message
+// type and epoch.
+func TopicFromMessage(msg string, epoch types.Epoch) (string, error) {
+	if !messageMapping[msg] {
+		return "", errors.Errorf("%s: %s", invalidRPCMessageType, msg)
+	}
+	version := SchemaVersionV1
+	isAltair := epoch >= params.BeaconConfig().AltairForkEpoch
+	if isAltair && altairMapping[msg] {
+		version = SchemaVersionV2
+	}
+	return protocolPrefix + msg + version, nil
+}

beacon-chain/p2p/rpc_topic_mappings_test.go

@@ -1,10 +1,15 @@
 package p2p
 
 import (
+	"fmt"
+	"strings"
 	"testing"
 
+	eth2types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/types"
 	pb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )
@@ -34,9 +39,9 @@ func TestTopicDeconstructor(t *testing.T) {
 		},
 		{
 			name:          "valid status topic",
-			topic:         protocolPrefix + statusMessageName + SchemaVersionV1,
+			topic:         protocolPrefix + StatusMessageName + SchemaVersionV1,
 			expectedError: "",
-			output:        []string{protocolPrefix, statusMessageName, SchemaVersionV1},
+			output:        []string{protocolPrefix, StatusMessageName, SchemaVersionV1},
 		},
 		{
 			name:          "malformed status topic",
@@ -46,13 +51,13 @@ func TestTopicDeconstructor(t *testing.T) {
 		},
 		{
 			name:          "valid beacon block by range topic",
-			topic:         protocolPrefix + beaconBlocksByRangeMessageName + SchemaVersionV1 + "/ssz_snappy",
+			topic:         protocolPrefix + BeaconBlocksByRangeMessageName + SchemaVersionV1 + "/ssz_snappy",
 			expectedError: "",
-			output:        []string{protocolPrefix, beaconBlocksByRangeMessageName, SchemaVersionV1},
+			output:        []string{protocolPrefix, BeaconBlocksByRangeMessageName, SchemaVersionV1},
 		},
 		{
 			name:          "beacon block by range topic with malformed version",
-			topic:         protocolPrefix + beaconBlocksByRangeMessageName + "/v" + "/ssz_snappy",
+			topic:         protocolPrefix + BeaconBlocksByRangeMessageName + "/v" + "/ssz_snappy",
 			expectedError: "unable to find a valid schema version for /eth2/beacon_chain/req/beacon_blocks_by_range/v/ssz_snappy",
 			output:        []string{""},
 		},
@@ -73,3 +78,45 @@ func TestTopicDeconstructor(t *testing.T) {
 		})
 	}
 }
+
+func TestTopicFromMessage_CorrectType(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	bCfg := params.BeaconConfig()
+	forkEpoch := eth2types.Epoch(100)
+	bCfg.AltairForkEpoch = forkEpoch
+	bCfg.ForkVersionSchedule[bytesutil.ToBytes4(bCfg.AltairForkVersion)] = eth2types.Epoch(100)
+	params.OverrideBeaconConfig(bCfg)
+
+	// Garbage Message
+	badMsg := "wljdjska"
+	_, err := TopicFromMessage(badMsg, 0)
+	assert.ErrorContains(t, fmt.Sprintf("%s: %s", invalidRPCMessageType, badMsg), err)
+	// Before Fork
+	for m := range messageMapping {
+		topic, err := TopicFromMessage(m, 0)
+		assert.NoError(t, err)
+
+		assert.Equal(t, true, strings.Contains(topic, SchemaVersionV1))
+		_, _, version, err := TopicDeconstructor(topic)
+		assert.NoError(t, err)
+		assert.Equal(t, SchemaVersionV1, version)
+	}
+
+	// After Fork
+	for m := range messageMapping {
+		topic, err := TopicFromMessage(m, forkEpoch)
+		assert.NoError(t, err)
+
+		if altairMapping[m] {
+			assert.Equal(t, true, strings.Contains(topic, SchemaVersionV2))
+			_, _, version, err := TopicDeconstructor(topic)
+			assert.NoError(t, err)
+			assert.Equal(t, SchemaVersionV2, version)
+		} else {
+			assert.Equal(t, true, strings.Contains(topic, SchemaVersionV1))
+			_, _, version, err := TopicDeconstructor(topic)
+			assert.NoError(t, err)
+			assert.Equal(t, SchemaVersionV1, version)
+		}
+	}
+}