fixing error inconsistency

* Validator custody: Update to the latest specfication.

* Update beacon-chain/blockchain/process_block.go

Co-authored-by: terence <terence@prysmaticlabs.com>

* Fix James' comment.

* Fix James' comment.

* Fix James' comment.

---------

Co-authored-by: terence <terence@prysmaticlabs.com>
Co-authored-by: james-prysm <90280386+james-prysm@users.noreply.github.com>

WORKSPACE

@@ -190,7 +190,7 @@ load("@rules_oci//oci:pull.bzl", "oci_pull")
 # A multi-arch base image
 oci_pull(
     name = "linux_debian11_multiarch_base",  # Debian bullseye
-    digest = "sha256:b82f113425c5b5c714151aaacd8039bc141821cdcd3c65202d42bdf9c43ae60b",  # 2023-12-12
+    digest = "sha256:55a5e011b2c4246b4c51e01fcc2b452d151e03df052e357465f0392fcd59fddf",
     image = "gcr.io/prysmaticlabs/distroless/cc-debian11",
     platforms = [
         "linux/amd64",
@@ -208,7 +208,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()
 
 go_register_toolchains(
-    go_version = "1.24.0",
+    go_version = "1.24.5",
     nogo = "@//:nogo",
 )
 

api/server/structs/BUILD.bazel

@@ -36,6 +36,7 @@ go_library(
         "//consensus-types/primitives:go_default_library",
         "//consensus-types/validator:go_default_library",
         "//container/slice:go_default_library",
+        "//crypto/bls:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//math:go_default_library",
         "//proto/engine/v1:go_default_library",

api/server/structs/conversions.go

@@ -10,6 +10,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/validator"
 	"github.com/OffchainLabs/prysm/v6/container/slice"
+	"github.com/OffchainLabs/prysm/v6/crypto/bls"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
 	"github.com/OffchainLabs/prysm/v6/math"
 	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
@@ -699,6 +700,11 @@ func (m *SyncCommitteeMessage) ToConsensus() (*eth.SyncCommitteeMessage, error)
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Signature")
 	}
+	// Add validation to check if the signature is valid BLS format
+	_, err = bls.SignatureFromBytes(sig)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
 
 	return &eth.SyncCommitteeMessage{
 		Slot:           primitives.Slot(slot),

beacon-chain/blockchain/BUILD.bazel

@@ -73,6 +73,7 @@ go_library(
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/stategen:go_default_library",
         "//beacon-chain/verification:go_default_library",
+        "//cmd/beacon-chain/flags:go_default_library",
         "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
@@ -194,6 +195,7 @@ go_test(
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_ethereum_go_ethereum//core/types:go_default_library",
         "@com_github_holiman_uint256//:go_default_library",
+        "@com_github_libp2p_go_libp2p//core/peer:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",

beacon-chain/blockchain/execution_engine.go

@@ -174,6 +174,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 			"payloadID": fmt.Sprintf("%#x", bytesutil.Trunc(payloadID[:])),
 		}).Info("Forkchoice updated with payload attributes for proposal")
 		s.cfg.PayloadIDCache.Set(nextSlot, arg.headRoot, pId)
+		go s.firePayloadAttributesEvent(s.cfg.StateNotifier.StateFeed(), arg.headBlock, arg.headRoot, nextSlot)
 	} else if hasAttr && payloadID == nil && !features.Get().PrepareAllPayloads {
 		log.WithFields(logrus.Fields{
 			"blockHash": fmt.Sprintf("%#x", headPayload.BlockHash()),

beacon-chain/blockchain/forkchoice_update_execution.go

@@ -102,8 +102,6 @@ func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, args *fcuCo
 		log.WithError(err).Error("Could not save head")
 	}
 
-	go s.firePayloadAttributesEvent(s.cfg.StateNotifier.StateFeed(), args.headBlock, args.headRoot, s.CurrentSlot()+1)
-
 	// Only need to prune attestations from pool if the head has changed.
 	s.pruneAttsFromPool(s.ctx, args.headState, args.headBlock)
 	return nil

beacon-chain/blockchain/options.go

@@ -7,7 +7,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution"
@@ -36,7 +35,7 @@ func WithMaxGoroutines(x int) Option {
 // WithLCStore for light client store access.
 func WithLCStore() Option {
 	return func(s *Service) error {
-		s.lcStore = lightclient.NewLightClientStore(s.cfg.BeaconDB)
+		s.lcStore = lightclient.NewLightClientStore(s.cfg.BeaconDB, s.cfg.P2P, s.cfg.StateNotifier.StateFeed())
 		return nil
 	}
 }
@@ -235,14 +234,6 @@ func WithSyncChecker(checker Checker) Option {
 	}
 }
 
-// WithCustodyInfo sets the custody info for the blockchain service.
-func WithCustodyInfo(custodyInfo *peerdas.CustodyInfo) Option {
-	return func(s *Service) error {
-		s.cfg.CustodyInfo = custodyInfo
-		return nil
-	}
-}
-
 // WithSlasherEnabled sets whether the slasher is enabled or not.
 func WithSlasherEnabled(enabled bool) Option {
 	return func(s *Service) error {

beacon-chain/blockchain/process_block.go

@@ -666,7 +666,9 @@ func (s *Service) areDataColumnsAvailable(
 	root [fieldparams.RootLength]byte,
 	block interfaces.ReadOnlyBeaconBlock,
 ) error {
-	// We are only required to check within MIN_EPOCHS_FOR_DATA_COLUMN_SIDECARS_REQUESTS.
+	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
+
+	// We are only required to check within MIN_EPOCHS_FOR_DATA_COLUMN_SIDECARS_REQUESTS
 	blockSlot, currentSlot := block.Slot(), s.CurrentSlot()
 	blockEpoch, currentEpoch := slots.ToEpoch(blockSlot), slots.ToEpoch(currentSlot)
 	if !params.WithinDAPeriod(blockEpoch, currentEpoch) {
@@ -689,16 +691,20 @@ func (s *Service) areDataColumnsAvailable(
 	}
 
 	// All columns to sample need to be available for the block to be considered available.
-	// https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.10/specs/fulu/das-core.md#custody-sampling
 	nodeID := s.cfg.P2P.NodeID()
 
-	// Prevent custody group count to change during the rest of the function.
-	s.cfg.CustodyInfo.Mut.RLock()
-	defer s.cfg.CustodyInfo.Mut.RUnlock()
-
 	// Get the custody group sampling size for the node.
-	custodyGroupSamplingSize := s.cfg.CustodyInfo.CustodyGroupSamplingSize(peerdas.Actual)
-	peerInfo, _, err := peerdas.Info(nodeID, custodyGroupSamplingSize)
+	custodyGroupCount, err := s.cfg.P2P.CustodyGroupCount()
+	if err != nil {
+		return errors.Wrap(err, "custody group count")
+	}
+
+	// Compute the sampling size.
+	// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/das-core.md#custody-sampling
+	samplingSize := max(samplesPerSlot, custodyGroupCount)
+
+	// Get the peer info for the node.
+	peerInfo, _, err := peerdas.Info(nodeID, samplingSize)
 	if err != nil {
 		return errors.Wrap(err, "peer info")
 	}

beacon-chain/blockchain/process_block_helpers.go

@@ -1,7 +1,6 @@
 package blockchain
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"strings"
@@ -198,8 +197,7 @@ func (s *Service) processLightClientFinalityUpdate(
 
 	finalizedCheckpoint := attestedState.FinalizedCheckpoint()
 
-	// Check if the finalized checkpoint has changed
-	if finalizedCheckpoint == nil || bytes.Equal(finalizedCheckpoint.GetRoot(), postState.FinalizedCheckpoint().Root) {
+	if finalizedCheckpoint == nil {
 		return nil
 	}
 
@@ -224,17 +222,7 @@ func (s *Service) processLightClientFinalityUpdate(
 		return nil
 	}
 
-	log.Debug("Saving new light client finality update")
-	s.lcStore.SetLastFinalityUpdate(newUpdate)
-
-	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.LightClientFinalityUpdate,
-		Data: newUpdate,
-	})
-
-	if err = s.cfg.P2P.BroadcastLightClientFinalityUpdate(ctx, newUpdate); err != nil {
-		return errors.Wrap(err, "could not broadcast light client finality update")
-	}
+	s.lcStore.SetLastFinalityUpdate(newUpdate, true)
 
 	return nil
 }
@@ -266,17 +254,7 @@ func (s *Service) processLightClientOptimisticUpdate(ctx context.Context, signed
 		return nil
 	}
 
-	log.Debug("Saving new light client optimistic update")
-	s.lcStore.SetLastOptimisticUpdate(newUpdate)
-
-	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.LightClientOptimisticUpdate,
-		Data: newUpdate,
-	})
-
-	if err = s.cfg.P2P.BroadcastLightClientOptimisticUpdate(ctx, newUpdate); err != nil {
-		return errors.Wrap(err, "could not broadcast light client optimistic update")
-	}
+	s.lcStore.SetLastOptimisticUpdate(newUpdate, true)
 
 	return nil
 }

beacon-chain/blockchain/process_block_test.go

@@ -2894,7 +2894,6 @@ func TestIsDataAvailable(t *testing.T) {
 		}
 
 		params := testIsAvailableParams{
-			options:                 []Option{WithCustodyInfo(&peerdas.CustodyInfo{})},
 			columnsToSave:           indices,
 			blobKzgCommitmentsCount: 3,
 		}
@@ -2907,7 +2906,6 @@ func TestIsDataAvailable(t *testing.T) {
 
 	t.Run("Fulu - no missing data columns", func(t *testing.T) {
 		params := testIsAvailableParams{
-			options:                 []Option{WithCustodyInfo(&peerdas.CustodyInfo{})},
 			columnsToSave:           []uint64{1, 17, 19, 42, 75, 87, 102, 117, 119}, // 119 is not needed
 			blobKzgCommitmentsCount: 3,
 		}
@@ -2922,7 +2920,7 @@ func TestIsDataAvailable(t *testing.T) {
 		startWaiting := make(chan bool)
 
 		testParams := testIsAvailableParams{
-			options:       []Option{WithCustodyInfo(&peerdas.CustodyInfo{}), WithStartWaitingDataColumnSidecars(startWaiting)},
+			options:       []Option{WithStartWaitingDataColumnSidecars(startWaiting)},
 			columnsToSave: []uint64{1, 17, 19, 75, 102, 117, 119}, // 119 is not needed, 42 and 87 are missing
 
 			blobKzgCommitmentsCount: 3,
@@ -2959,6 +2957,9 @@ func TestIsDataAvailable(t *testing.T) {
 			require.NoError(t, err)
 		}()
 
+		ctx, cancel := context.WithTimeout(ctx, time.Second*2)
+		defer cancel()
+
 		err = service.isDataAvailable(ctx, root, signed)
 		require.NoError(t, err)
 	})
@@ -2971,10 +2972,6 @@ func TestIsDataAvailable(t *testing.T) {
 
 		startWaiting := make(chan bool)
 
-		var custodyInfo peerdas.CustodyInfo
-		custodyInfo.TargetGroupCount.SetValidatorsCustodyRequirement(cgc)
-		custodyInfo.ToAdvertiseGroupCount.Set(cgc)
-
 		minimumColumnsCountToReconstruct := peerdas.MinimumColumnsCountToReconstruct()
 		indices := make([]uint64, 0, minimumColumnsCountToReconstruct-missingColumns)
 
@@ -2983,12 +2980,14 @@ func TestIsDataAvailable(t *testing.T) {
 		}
 
 		testParams := testIsAvailableParams{
-			options:                 []Option{WithCustodyInfo(&custodyInfo), WithStartWaitingDataColumnSidecars(startWaiting)},
+			options:                 []Option{WithStartWaitingDataColumnSidecars(startWaiting)},
 			columnsToSave:           indices,
 			blobKzgCommitmentsCount: 3,
 		}
 
 		ctx, _, service, root, signed := testIsAvailableSetup(t, testParams)
+		_, _, err := service.cfg.P2P.UpdateCustodyInfo(0, cgc)
+		require.NoError(t, err)
 		block := signed.Block()
 		slot := block.Slot()
 		proposerIndex := block.ProposerIndex()
@@ -3020,6 +3019,9 @@ func TestIsDataAvailable(t *testing.T) {
 			require.NoError(t, err)
 		}()
 
+		ctx, cancel := context.WithTimeout(ctx, time.Second*2)
+		defer cancel()
+
 		err = service.isDataAvailable(ctx, root, signed)
 		require.NoError(t, err)
 	})
@@ -3028,7 +3030,7 @@ func TestIsDataAvailable(t *testing.T) {
 		startWaiting := make(chan bool)
 
 		params := testIsAvailableParams{
-			options:                 []Option{WithCustodyInfo(&peerdas.CustodyInfo{}), WithStartWaitingDataColumnSidecars(startWaiting)},
+			options:                 []Option{WithStartWaitingDataColumnSidecars(startWaiting)},
 			blobKzgCommitmentsCount: 3,
 		}
 
@@ -3170,7 +3172,7 @@ func TestProcessLightClientOptimisticUpdate(t *testing.T) {
 
 			t.Run(version.String(testVersion)+"_"+tc.name, func(t *testing.T) {
 				s.genesisTime = time.Unix(time.Now().Unix()-(int64(forkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
-				s.lcStore = &lightClient.Store{}
+				s.lcStore = lightClient.NewLightClientStore(s.cfg.BeaconDB, s.cfg.P2P, s.cfg.StateNotifier.StateFeed())
 
 				var oldActualUpdate interfaces.LightClientOptimisticUpdate
 				var err error
@@ -3246,39 +3248,39 @@ func TestProcessLightClientFinalityUpdate(t *testing.T) {
 			expectReplace: true,
 		},
 		{
-			name:          "Old update is better - age - no supermajority",
+			name:          "Old update is better - finalized slot is higher",
 			oldOptions:    []util.LightClientOption{util.WithIncreasedFinalizedSlot(1)},
 			newOptions:    []util.LightClientOption{},
 			expectReplace: false,
 		},
 		{
-			name:          "Old update is better - age - both supermajority",
-			oldOptions:    []util.LightClientOption{util.WithIncreasedFinalizedSlot(1), util.WithSupermajority()},
-			newOptions:    []util.LightClientOption{util.WithSupermajority()},
-			expectReplace: false,
-		},
-		{
-			name:          "Old update is better - supermajority",
-			oldOptions:    []util.LightClientOption{util.WithSupermajority()},
+			name:          "Old update is better - attested slot is higher",
+			oldOptions:    []util.LightClientOption{util.WithIncreasedAttestedSlot(1)},
 			newOptions:    []util.LightClientOption{},
 			expectReplace: false,
 		},
 		{
-			name:          "New update is better - age - both supermajority",
-			oldOptions:    []util.LightClientOption{util.WithSupermajority()},
-			newOptions:    []util.LightClientOption{util.WithIncreasedFinalizedSlot(1), util.WithSupermajority()},
+			name:          "Old update is better - signature slot is higher",
+			oldOptions:    []util.LightClientOption{util.WithIncreasedSignatureSlot(1)},
+			newOptions:    []util.LightClientOption{},
+			expectReplace: false,
+		},
+		{
+			name:          "New update is better - finalized slot is higher",
+			oldOptions:    []util.LightClientOption{},
+			newOptions:    []util.LightClientOption{util.WithIncreasedAttestedSlot(1)},
 			expectReplace: true,
 		},
 		{
-			name:          "New update is better - age - no supermajority",
+			name:          "New update is better - attested slot is higher",
 			oldOptions:    []util.LightClientOption{},
-			newOptions:    []util.LightClientOption{util.WithIncreasedFinalizedSlot(1)},
+			newOptions:    []util.LightClientOption{util.WithIncreasedAttestedSlot(1)},
 			expectReplace: true,
 		},
 		{
-			name:          "New update is better - supermajority",
+			name:          "New update is better - signature slot is higher",
 			oldOptions:    []util.LightClientOption{},
-			newOptions:    []util.LightClientOption{util.WithSupermajority()},
+			newOptions:    []util.LightClientOption{util.WithIncreasedSignatureSlot(1)},
 			expectReplace: true,
 		},
 	}
@@ -3310,7 +3312,7 @@ func TestProcessLightClientFinalityUpdate(t *testing.T) {
 
 			t.Run(version.String(testVersion)+"_"+tc.name, func(t *testing.T) {
 				s.genesisTime = time.Unix(time.Now().Unix()-(int64(forkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
-				s.lcStore = &lightClient.Store{}
+				s.lcStore = lightClient.NewLightClientStore(s.cfg.BeaconDB, s.cfg.P2P, s.cfg.StateNotifier.StateFeed())
 
 				var actualOldUpdate, actualNewUpdate interfaces.LightClientFinalityUpdate
 				var err error

beacon-chain/blockchain/service.go

@@ -16,7 +16,6 @@ import (
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	coreTime "github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
@@ -31,6 +30,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state/stategen"
+	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
@@ -97,7 +97,6 @@ type config struct {
 	FinalizedStateAtStartUp state.BeaconState
 	ExecutionEngineCaller   execution.EngineCaller
 	SyncChecker             Checker
-	CustodyInfo             *peerdas.CustodyInfo
 }
 
 // Checker is an interface used to determine if a node is in initial sync
@@ -296,6 +295,20 @@ func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 	if err := s.clockSetter.SetClock(startup.NewClock(s.genesisTime, vr)); err != nil {
 		return errors.Wrap(err, "failed to initialize blockchain service")
 	}
+
+	if !params.FuluEnabled() {
+		return nil
+	}
+
+	earliestAvailableSlot, custodySubnetCount, err := s.updateCustodyInfoInDB(saved.Slot())
+	if err != nil {
+		return errors.Wrap(err, "could not get and save custody group count")
+	}
+
+	if _, _, err := s.cfg.P2P.UpdateCustodyInfo(earliestAvailableSlot, custodySubnetCount); err != nil {
+		return errors.Wrap(err, "update custody info")
+	}
+
 	return nil
 }
 
@@ -516,6 +529,57 @@ func (s *Service) removeStartupState() {
 	s.cfg.FinalizedStateAtStartUp = nil
 }
 
+// UpdateCustodyInfoInDB updates the custody information in the database.
+// It returns the (potentially updated) custody group count and the earliest available slot.
+func (s *Service) updateCustodyInfoInDB(slot primitives.Slot) (primitives.Slot, uint64, error) {
+	isSubscribedToAllDataSubnets := flags.Get().SubscribeAllDataSubnets
+
+	beaconConfig := params.BeaconConfig()
+	custodyRequirement := beaconConfig.CustodyRequirement
+
+	// Check if the node was previously subscribed to all data subnets, and if so,
+	// store the new status accordingly.
+	wasSubscribedToAllDataSubnets, err := s.cfg.BeaconDB.UpdateSubscribedToAllDataSubnets(s.ctx, isSubscribedToAllDataSubnets)
+	if err != nil {
+		log.WithError(err).Error("Could not update subscription status to all data subnets")
+	}
+
+	// Warn the user if the node was previously subscribed to all data subnets and is not any more.
+	if wasSubscribedToAllDataSubnets && !isSubscribedToAllDataSubnets {
+		log.Warnf(
+			"Because the flag `--%s` was previously used, the node will still subscribe to all data subnets.",
+			flags.SubscribeAllDataSubnets.Name,
+		)
+	}
+
+	// Compute the custody group count.
+	custodyGroupCount := custodyRequirement
+	if isSubscribedToAllDataSubnets {
+		custodyGroupCount = beaconConfig.NumberOfColumns
+	}
+
+	// Safely compute the fulu fork slot.
+	fuluForkSlot, err := fuluForkSlot()
+	if err != nil {
+		return 0, 0, errors.Wrap(err, "fulu fork slot")
+	}
+
+	// If slot is before the fulu fork slot, then use the earliest stored slot as the reference slot.
+	if slot < fuluForkSlot {
+		slot, err = s.cfg.BeaconDB.EarliestSlot(s.ctx)
+		if err != nil {
+			return 0, 0, errors.Wrap(err, "earliest slot")
+		}
+	}
+
+	earliestAvailableSlot, custodyGroupCount, err := s.cfg.BeaconDB.UpdateCustodyInfo(s.ctx, slot, custodyGroupCount)
+	if err != nil {
+		return 0, 0, errors.Wrap(err, "update custody info")
+	}
+
+	return earliestAvailableSlot, custodyGroupCount, nil
+}
+
 func spawnCountdownIfPreGenesis(ctx context.Context, genesisTime time.Time, db db.HeadAccessDatabase) {
 	currentTime := prysmTime.Now()
 	if currentTime.After(genesisTime) {
@@ -532,3 +596,19 @@ func spawnCountdownIfPreGenesis(ctx context.Context, genesisTime time.Time, db d
 	}
 	go slots.CountdownToGenesis(ctx, genesisTime, uint64(gState.NumValidators()), gRoot)
 }
+
+func fuluForkSlot() (primitives.Slot, error) {
+	beaconConfig := params.BeaconConfig()
+
+	fuluForkEpoch := beaconConfig.FuluForkEpoch
+	if fuluForkEpoch == beaconConfig.FarFutureEpoch {
+		return beaconConfig.FarFutureSlot, nil
+	}
+
+	forkFuluSlot, err := slots.EpochStart(fuluForkEpoch)
+	if err != nil {
+		return 0, errors.Wrap(err, "epoch start")
+	}
+
+	return forkFuluSlot, nil
+}

beacon-chain/blockchain/setup_test.go

@@ -30,6 +30,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
+	"github.com/libp2p/go-libp2p/core/peer"
 	"google.golang.org/protobuf/proto"
 )
 
@@ -54,6 +55,7 @@ type mockBroadcaster struct {
 
 type mockAccessor struct {
 	mockBroadcaster
+	mockCustodyManager
 	p2pTesting.MockPeerManager
 }
 
@@ -97,6 +99,43 @@ func (mb *mockBroadcaster) BroadcastBLSChanges(_ context.Context, _ []*ethpb.Sig
 
 var _ p2p.Broadcaster = (*mockBroadcaster)(nil)
 
+// mockCustodyManager is a mock implementation of p2p.CustodyManager
+type mockCustodyManager struct {
+	mut                   sync.RWMutex
+	earliestAvailableSlot primitives.Slot
+	custodyGroupCount     uint64
+}
+
+func (dch *mockCustodyManager) EarliestAvailableSlot() (primitives.Slot, error) {
+	dch.mut.RLock()
+	defer dch.mut.RUnlock()
+
+	return dch.earliestAvailableSlot, nil
+}
+
+func (dch *mockCustodyManager) CustodyGroupCount() (uint64, error) {
+	dch.mut.RLock()
+	defer dch.mut.RUnlock()
+
+	return dch.custodyGroupCount, nil
+}
+
+func (dch *mockCustodyManager) UpdateCustodyInfo(earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error) {
+	dch.mut.Lock()
+	defer dch.mut.Unlock()
+
+	dch.earliestAvailableSlot = earliestAvailableSlot
+	dch.custodyGroupCount = custodyGroupCount
+
+	return earliestAvailableSlot, custodyGroupCount, nil
+}
+
+func (dch *mockCustodyManager) CustodyGroupCountFromPeer(peer.ID) uint64 {
+	return 0
+}
+
+var _ p2p.CustodyManager = (*mockCustodyManager)(nil)
+
 type testServiceRequirements struct {
 	ctx     context.Context
 	db      db.Database

beacon-chain/core/electra/withdrawals.go

@@ -102,13 +102,13 @@ func ProcessWithdrawalRequests(ctx context.Context, st state.BeaconState, wrs []
 			return nil, err
 		} else if n == params.BeaconConfig().PendingPartialWithdrawalsLimit && !isFullExitRequest {
 			// if the PendingPartialWithdrawalsLimit is met, the user would have paid for a partial withdrawal that's not included
-			log.Debugln("Skipping execution layer withdrawal request, PendingPartialWithdrawalsLimit reached")
+			log.Debug("Skipping execution layer withdrawal request, PendingPartialWithdrawalsLimit reached")
 			continue
 		}
 
 		vIdx, exists := st.ValidatorIndexByPubkey(bytesutil.ToBytes48(wr.ValidatorPubkey))
 		if !exists {
-			log.Debugf("Skipping execution layer withdrawal request, validator index for %s not found\n", hexutil.Encode(wr.ValidatorPubkey))
+			log.WithField("validator", hexutil.Encode(wr.ValidatorPubkey)).Debug("Skipping execution layer withdrawal request, validator index not found")
 			continue
 		}
 		validator, err := st.ValidatorAtIndexReadOnly(vIdx)
@@ -120,23 +120,23 @@ func ProcessWithdrawalRequests(ctx context.Context, st state.BeaconState, wrs []
 		wc := validator.GetWithdrawalCredentials()
 		isCorrectSourceAddress := bytes.Equal(wc[12:], wr.SourceAddress)
 		if !hasCorrectCredential || !isCorrectSourceAddress {
-			log.Debugln("Skipping execution layer withdrawal request, wrong withdrawal credentials")
+			log.Debug("Skipping execution layer withdrawal request, wrong withdrawal credentials")
 			continue
 		}
 
 		// Verify the validator is active.
 		if !helpers.IsActiveValidatorUsingTrie(validator, currentEpoch) {
-			log.Debugln("Skipping execution layer withdrawal request, validator not active")
+			log.Debug("Skipping execution layer withdrawal request, validator not active")
 			continue
 		}
 		// Verify the validator has not yet submitted an exit.
 		if validator.ExitEpoch() != params.BeaconConfig().FarFutureEpoch {
-			log.Debugln("Skipping execution layer withdrawal request, validator has submitted an exit already")
+			log.Debug("Skipping execution layer withdrawal request, validator has submitted an exit already")
 			continue
 		}
 		// Verify the validator has been active long enough.
 		if currentEpoch < validator.ActivationEpoch().AddEpoch(params.BeaconConfig().ShardCommitteePeriod) {
-			log.Debugln("Skipping execution layer withdrawal request, validator has not been active long enough")
+			log.Debug("Skipping execution layer withdrawal request, validator has not been active long enough")
 			continue
 		}
 

beacon-chain/core/fulu/upgrade.go

@@ -15,7 +15,7 @@ import (
 )
 
 // UpgradeToFulu updates inputs a generic state to return the version Fulu state.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/fork.md#upgrading-the-state
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/fork.md#upgrading-the-state
 func UpgradeToFulu(ctx context.Context, beaconState state.BeaconState) (state.BeaconState, error) {
 	currentSyncCommittee, err := beaconState.CurrentSyncCommittee()
 	if err != nil {

beacon-chain/core/light-client/BUILD.bazel

@@ -10,8 +10,12 @@ go_library(
     importpath = "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client",
     visibility = ["//visibility:public"],
     deps = [
+        "//async/event:go_default_library",
+        "//beacon-chain/core/feed:go_default_library",
+        "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/db/iface:go_default_library",
         "//beacon-chain/execution:go_default_library",
+        "//beacon-chain/p2p:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
@@ -39,6 +43,9 @@ go_test(
     ],
     deps = [
         ":go_default_library",
+        "//async/event:go_default_library",
+        "//beacon-chain/db/testing:go_default_library",
+        "//beacon-chain/p2p/testing:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types:go_default_library",

beacon-chain/core/light-client/lightclient.go

@@ -750,7 +750,9 @@ func UpdateHasSupermajority(syncAggregate *pb.SyncAggregate) bool {
 	return numActiveParticipants*3 >= maxActiveParticipants*2
 }
 
-func IsBetterFinalityUpdate(newUpdate, oldUpdate interfaces.LightClientFinalityUpdate) bool {
+// IsFinalityUpdateValidForBroadcast checks if a finality update needs to be broadcasted.
+// It is also used to check if an incoming gossiped finality update is valid for forwarding and saving.
+func IsFinalityUpdateValidForBroadcast(newUpdate, oldUpdate interfaces.LightClientFinalityUpdate) bool {
 	if oldUpdate == nil {
 		return true
 	}
@@ -772,6 +774,35 @@ func IsBetterFinalityUpdate(newUpdate, oldUpdate interfaces.LightClientFinalityU
 	return true
 }
 
+// IsBetterFinalityUpdate checks if the new finality update is better than the old one for saving.
+// This does not concern broadcasting, but rather the decision of whether to save the new update.
+// For broadcasting checks, use IsFinalityUpdateValidForBroadcast.
+func IsBetterFinalityUpdate(newUpdate, oldUpdate interfaces.LightClientFinalityUpdate) bool {
+	if oldUpdate == nil {
+		return true
+	}
+
+	// Full nodes SHOULD provide the LightClientFinalityUpdate with the highest attested_header.beacon.slot (if multiple, highest signature_slot)
+	newFinalizedSlot := newUpdate.FinalizedHeader().Beacon().Slot
+	newAttestedSlot := newUpdate.AttestedHeader().Beacon().Slot
+
+	oldFinalizedSlot := oldUpdate.FinalizedHeader().Beacon().Slot
+	oldAttestedSlot := oldUpdate.AttestedHeader().Beacon().Slot
+
+	if newFinalizedSlot < oldFinalizedSlot {
+		return false
+	}
+	if newFinalizedSlot == oldFinalizedSlot {
+		if newAttestedSlot < oldAttestedSlot {
+			return false
+		}
+		if newAttestedSlot == oldAttestedSlot && newUpdate.SignatureSlot() <= oldUpdate.SignatureSlot() {
+			return false
+		}
+	}
+	return true
+}
+
 func IsBetterOptimisticUpdate(newUpdate, oldUpdate interfaces.LightClientOptimisticUpdate) bool {
 	if oldUpdate == nil {
 		return true

beacon-chain/core/light-client/store.go

@@ -4,7 +4,11 @@ import (
 	"context"
 	"sync"
 
+	"github.com/OffchainLabs/prysm/v6/async/event"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed"
+	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/iface"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
@@ -16,13 +20,17 @@ type Store struct {
 	mu sync.RWMutex
 
 	beaconDB             iface.HeadAccessDatabase
-	lastFinalityUpdate   interfaces.LightClientFinalityUpdate
-	lastOptimisticUpdate interfaces.LightClientOptimisticUpdate
+	lastFinalityUpdate   interfaces.LightClientFinalityUpdate   // tracks the best finality update seen so far
+	lastOptimisticUpdate interfaces.LightClientOptimisticUpdate // tracks the best optimistic update seen so far
+	p2p                  p2p.Accessor
+	stateFeed            event.SubscriberSender
 }
 
-func NewLightClientStore(db iface.HeadAccessDatabase) *Store {
+func NewLightClientStore(db iface.HeadAccessDatabase, p p2p.Accessor, e event.SubscriberSender) *Store {
 	return &Store{
-		beaconDB: db,
+		beaconDB:  db,
+		p2p:       p,
+		stateFeed: e,
 	}
 }
 
@@ -143,10 +151,23 @@ func (s *Store) SaveLightClientUpdate(ctx context.Context, period uint64, update
 	return nil
 }
 
-func (s *Store) SetLastFinalityUpdate(update interfaces.LightClientFinalityUpdate) {
+func (s *Store) SetLastFinalityUpdate(update interfaces.LightClientFinalityUpdate, broadcast bool) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
+
+	if broadcast && IsFinalityUpdateValidForBroadcast(update, s.lastFinalityUpdate) {
+		if err := s.p2p.BroadcastLightClientFinalityUpdate(context.Background(), update); err != nil {
+			log.WithError(err).Error("Could not broadcast light client finality update")
+		}
+	}
+
 	s.lastFinalityUpdate = update
+	log.Debug("Saved new light client finality update")
+
+	s.stateFeed.Send(&feed.Event{
+		Type: statefeed.LightClientFinalityUpdate,
+		Data: update,
+	})
 }
 
 func (s *Store) LastFinalityUpdate() interfaces.LightClientFinalityUpdate {
@@ -155,10 +176,23 @@ func (s *Store) LastFinalityUpdate() interfaces.LightClientFinalityUpdate {
 	return s.lastFinalityUpdate
 }
 
-func (s *Store) SetLastOptimisticUpdate(update interfaces.LightClientOptimisticUpdate) {
+func (s *Store) SetLastOptimisticUpdate(update interfaces.LightClientOptimisticUpdate, broadcast bool) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
+
+	if broadcast {
+		if err := s.p2p.BroadcastLightClientOptimisticUpdate(context.Background(), update); err != nil {
+			log.WithError(err).Error("Could not broadcast light client optimistic update")
+		}
+	}
+
 	s.lastOptimisticUpdate = update
+	log.Debug("Saved new light client optimistic update")
+
+	s.stateFeed.Send(&feed.Event{
+		Type: statefeed.LightClientOptimisticUpdate,
+		Data: update,
+	})
 }
 
 func (s *Store) LastOptimisticUpdate() interfaces.LightClientOptimisticUpdate {

beacon-chain/core/light-client/store_test.go

@@ -3,7 +3,10 @@ package light_client_test
 import (
 	"testing"
 
+	"github.com/OffchainLabs/prysm/v6/async/event"
 	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
+	testDB "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
+	p2pTesting "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
@@ -21,7 +24,7 @@ func TestLightClientStore(t *testing.T) {
 	params.OverrideBeaconConfig(cfg)
 
 	// Initialize the light client store
-	lcStore := &lightClient.Store{}
+	lcStore := lightClient.NewLightClientStore(testDB.SetupDB(t), &p2pTesting.FakeP2P{}, new(event.Feed))
 
 	// Create test light client updates for Capella and Deneb
 	lCapella := util.NewTestLightClient(t, version.Capella)
@@ -45,24 +48,118 @@ func TestLightClientStore(t *testing.T) {
 	require.IsNil(t, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate should be nil")
 
 	// Set and get finality with Capella update. Optimistic update should be nil
-	lcStore.SetLastFinalityUpdate(finUpdateCapella)
+	lcStore.SetLastFinalityUpdate(finUpdateCapella, false)
 	require.Equal(t, finUpdateCapella, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
 	require.IsNil(t, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate should be nil")
 
 	// Set and get optimistic with Capella update. Finality update should be Capella
-	lcStore.SetLastOptimisticUpdate(opUpdateCapella)
+	lcStore.SetLastOptimisticUpdate(opUpdateCapella, false)
 	require.Equal(t, opUpdateCapella, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate is wrong")
 	require.Equal(t, finUpdateCapella, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
 
 	// Set and get finality and optimistic with Deneb update
-	lcStore.SetLastFinalityUpdate(finUpdateDeneb)
-	lcStore.SetLastOptimisticUpdate(opUpdateDeneb)
+	lcStore.SetLastFinalityUpdate(finUpdateDeneb, false)
+	lcStore.SetLastOptimisticUpdate(opUpdateDeneb, false)
 	require.Equal(t, finUpdateDeneb, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
 	require.Equal(t, opUpdateDeneb, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate is wrong")
-
-	// Set and get finality and optimistic with nil update
-	lcStore.SetLastFinalityUpdate(nil)
-	lcStore.SetLastOptimisticUpdate(nil)
-	require.IsNil(t, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should be nil")
-	require.IsNil(t, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate should be nil")
+}
+
+func TestLightClientStore_SetLastFinalityUpdate(t *testing.T) {
+	p2p := p2pTesting.NewTestP2P(t)
+	lcStore := lightClient.NewLightClientStore(testDB.SetupDB(t), p2p, new(event.Feed))
+
+	// update 0 with basic data and no supermajority following an empty lastFinalityUpdate - should save and broadcast
+	l0 := util.NewTestLightClient(t, version.Altair)
+	update0, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l0.Ctx, l0.State, l0.Block, l0.AttestedState, l0.AttestedBlock, l0.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update0, lcStore.LastFinalityUpdate()), "update0 should be better than nil")
+	// update0 should be valid for broadcast - meaning it should be broadcasted
+	require.Equal(t, true, lightClient.IsFinalityUpdateValidForBroadcast(update0, lcStore.LastFinalityUpdate()), "update0 should be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update0, true)
+	require.Equal(t, update0, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after setting a new last finality update when previous is nil")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 1 with same finality slot, increased attested slot, and no supermajority - should save but not broadcast
+	l1 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(1))
+	update1, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l1.Ctx, l1.State, l1.Block, l1.AttestedState, l1.AttestedBlock, l1.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update1, update0), "update1 should be better than update0")
+	// update1 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update1, lcStore.LastFinalityUpdate()), "update1 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update1, true)
+	require.Equal(t, update1, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called after setting a new last finality update without supermajority")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 2 with same finality slot, increased attested slot, and supermajority - should save and broadcast
+	l2 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(2), util.WithSupermajority())
+	update2, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update2, update1), "update2 should be better than update1")
+	// update2 should be valid for broadcast - meaning it should be broadcasted
+	require.Equal(t, true, lightClient.IsFinalityUpdateValidForBroadcast(update2, lcStore.LastFinalityUpdate()), "update2 should be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update2, true)
+	require.Equal(t, update2, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after setting a new last finality update with supermajority")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 3 with same finality slot, increased attested slot, and supermajority - should save but not broadcast
+	l3 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(3), util.WithSupermajority())
+	update3, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l3.Ctx, l3.State, l3.Block, l3.AttestedState, l3.AttestedBlock, l3.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update3, update2), "update3 should be better than update2")
+	// update3 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update3, lcStore.LastFinalityUpdate()), "update3 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update3, true)
+	require.Equal(t, update3, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been when previous was already broadcast")
+
+	// update 4 with increased finality slot, increased attested slot, and supermajority - should save and broadcast
+	l4 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(1), util.WithSupermajority())
+	update4, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l4.Ctx, l4.State, l4.Block, l4.AttestedState, l4.AttestedBlock, l4.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update4, update3), "update4 should be better than update3")
+	// update4 should be valid for broadcast - meaning it should be broadcasted
+	require.Equal(t, true, lightClient.IsFinalityUpdateValidForBroadcast(update4, lcStore.LastFinalityUpdate()), "update4 should be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update4, true)
+	require.Equal(t, update4, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after a new finality update with increased finality slot")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 5 with the same new finality slot, increased attested slot, and supermajority - should save but not broadcast
+	l5 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(2), util.WithSupermajority())
+	update5, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l5.Ctx, l5.State, l5.Block, l5.AttestedState, l5.AttestedBlock, l5.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update5, update4), "update5 should be better than update4")
+	// update5 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update5, lcStore.LastFinalityUpdate()), "update5 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update5, true)
+	require.Equal(t, update5, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called when previous was already broadcast with supermajority")
+
+	// update 6 with the same new finality slot, increased attested slot, and no supermajority - should save but not broadcast
+	l6 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(3))
+	update6, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l6.Ctx, l6.State, l6.Block, l6.AttestedState, l6.AttestedBlock, l6.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update6, update5), "update6 should be better than update5")
+	// update6 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update6, lcStore.LastFinalityUpdate()), "update6 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update6, true)
+	require.Equal(t, update6, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called when previous was already broadcast with supermajority")
 }

beacon-chain/core/peerdas/BUILD.bazel

@@ -16,7 +16,6 @@ go_library(
     deps = [
         "//beacon-chain/blockchain/kzg:go_default_library",
         "//beacon-chain/state:go_default_library",
-        "//cmd/beacon-chain/flags:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
@@ -53,7 +52,6 @@ go_test(
         ":go_default_library",
         "//beacon-chain/blockchain/kzg:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",
-        "//cmd/beacon-chain/flags:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",

beacon-chain/core/peerdas/das_core.go

@@ -31,15 +31,8 @@ var (
 	maxUint256 = &uint256.Int{math.MaxUint64, math.MaxUint64, math.MaxUint64, math.MaxUint64}
 )
 
-type CustodyType int
-
-const (
-	Target CustodyType = iota
-	Actual
-)
-
 // CustodyGroups computes the custody groups the node should participate in for custody.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/das-core.md#get_custody_groups
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/das-core.md#get_custody_groups
 func CustodyGroups(nodeId enode.ID, custodyGroupCount uint64) ([]uint64, error) {
 	numberOfCustodyGroups := params.BeaconConfig().NumberOfCustodyGroups
 
@@ -102,7 +95,7 @@ func CustodyGroups(nodeId enode.ID, custodyGroupCount uint64) ([]uint64, error)
 }
 
 // ComputeColumnsForCustodyGroup computes the columns for a given custody group.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/das-core.md#compute_columns_for_custody_group
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/das-core.md#compute_columns_for_custody_group
 func ComputeColumnsForCustodyGroup(custodyGroup uint64) ([]uint64, error) {
 	beaconConfig := params.BeaconConfig()
 	numberOfCustodyGroups := beaconConfig.NumberOfCustodyGroups
@@ -127,7 +120,7 @@ func ComputeColumnsForCustodyGroup(custodyGroup uint64) ([]uint64, error) {
 // DataColumnSidecars computes the data column sidecars from the signed block, cells and cell proofs.
 // The returned value contains pointers to function parameters.
 // (If the caller alterates `cellsAndProofs` afterwards, the returned value will be modified as well.)
-// https://github.com/ethereum/consensus-specs/blob/v1.6.0-alpha.3/specs/fulu/validator.md#get_data_column_sidecars_from_block
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_block
 func DataColumnSidecars(signedBlock interfaces.ReadOnlySignedBeaconBlock, cellsAndProofs []kzg.CellsAndProofs) ([]*ethpb.DataColumnSidecar, error) {
 	if signedBlock == nil || signedBlock.IsNil() || len(cellsAndProofs) == 0 {
 		return nil, nil
@@ -176,19 +169,6 @@ func ComputeCustodyGroupForColumn(columnIndex uint64) (uint64, error) {
 	return columnIndex % numberOfCustodyGroups, nil
 }
 
-// CustodyGroupSamplingSize returns the number of custody groups the node should sample from.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/das-core.md#custody-sampling
-func (custodyInfo *CustodyInfo) CustodyGroupSamplingSize(ct CustodyType) uint64 {
-	custodyGroupCount := custodyInfo.TargetGroupCount.Get()
-
-	if ct == Actual {
-		custodyGroupCount = custodyInfo.ActualGroupCount()
-	}
-
-	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
-	return max(samplesPerSlot, custodyGroupCount)
-}
-
 // CustodyColumns computes the custody columns from the custody groups.
 func CustodyColumns(custodyGroups []uint64) (map[uint64]bool, error) {
 	numberOfCustodyGroups := params.BeaconConfig().NumberOfCustodyGroups
@@ -219,7 +199,7 @@ func CustodyColumns(custodyGroups []uint64) (map[uint64]bool, error) {
 // the KZG commitment includion proofs and cells and cell proofs.
 // The returned value contains pointers to function parameters.
 // (If the caller alterates input parameters afterwards, the returned value will be modified as well.)
-// https://github.com/ethereum/consensus-specs/blob/v1.6.0-alpha.3/specs/fulu/validator.md#get_data_column_sidecars
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars
 func dataColumnsSidecars(
 	signedBlockHeader *ethpb.SignedBeaconBlockHeader,
 	blobKzgCommitments [][]byte,

beacon-chain/core/peerdas/das_core_test.go

@@ -104,62 +104,6 @@ func TestComputeCustodyGroupForColumn(t *testing.T) {
 	})
 }
 
-func TestCustodyGroupSamplingSize(t *testing.T) {
-	testCases := []struct {
-		name                         string
-		custodyType                  peerdas.CustodyType
-		validatorsCustodyRequirement uint64
-		toAdvertiseCustodyGroupCount uint64
-		expected                     uint64
-	}{
-		{
-			name:                         "target, lower than samples per slot",
-			custodyType:                  peerdas.Target,
-			validatorsCustodyRequirement: 2,
-			expected:                     8,
-		},
-		{
-			name:                         "target, higher than samples per slot",
-			custodyType:                  peerdas.Target,
-			validatorsCustodyRequirement: 100,
-			expected:                     100,
-		},
-		{
-			name:                         "actual, lower than samples per slot",
-			custodyType:                  peerdas.Actual,
-			validatorsCustodyRequirement: 3,
-			toAdvertiseCustodyGroupCount: 4,
-			expected:                     8,
-		},
-		{
-			name:                         "actual, higher than samples per slot",
-			custodyType:                  peerdas.Actual,
-			validatorsCustodyRequirement: 100,
-			toAdvertiseCustodyGroupCount: 101,
-			expected:                     100,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			// Create a custody info.
-			custodyInfo := peerdas.CustodyInfo{}
-
-			// Set the validators custody requirement for target custody group count.
-			custodyInfo.TargetGroupCount.SetValidatorsCustodyRequirement(tc.validatorsCustodyRequirement)
-
-			// Set the to advertise custody group count.
-			custodyInfo.ToAdvertiseGroupCount.Set(tc.toAdvertiseCustodyGroupCount)
-
-			// Compute the custody group sampling size.
-			actual := custodyInfo.CustodyGroupSamplingSize(tc.custodyType)
-
-			// Check the result.
-			require.Equal(t, tc.expected, actual)
-		})
-	}
-}
-
 func TestCustodyColumns(t *testing.T) {
 	t.Run("group too large", func(t *testing.T) {
 		_, err := peerdas.CustodyColumns([]uint64{1_000_000})

beacon-chain/core/peerdas/info.go

@@ -4,45 +4,17 @@ import (
 	"encoding/binary"
 	"sync"
 
-	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
-	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	lru "github.com/hashicorp/golang-lru"
 	"github.com/pkg/errors"
 )
 
 // info contains all useful peerDAS related information regarding a peer.
-type (
-	info struct {
-		CustodyGroups      map[uint64]bool
-		CustodyColumns     map[uint64]bool
-		DataColumnsSubnets map[uint64]bool
-	}
-
-	targetCustodyGroupCount struct {
-		mut                          sync.RWMutex
-		validatorsCustodyRequirement uint64
-	}
-
-	toAdverstiseCustodyGroupCount struct {
-		mut   sync.RWMutex
-		value uint64
-	}
-
-	CustodyInfo struct {
-		// Mut is a mutex to be used by caller to ensure neither
-		// TargetCustodyGroupCount nor ToAdvertiseCustodyGroupCount are being modified.
-		// (This is not necessary to use this mutex for any data protection.)
-		Mut sync.RWMutex
-
-		// TargetGroupCount represents the target number of custody groups we should custody
-		// regarding the validators we are tracking.
-		TargetGroupCount targetCustodyGroupCount
-
-		// ToAdvertiseGroupCount represents the number of custody groups to advertise to the network.
-		ToAdvertiseGroupCount toAdverstiseCustodyGroupCount
-	}
-)
+type info struct {
+	CustodyGroups      map[uint64]bool
+	CustodyColumns     map[uint64]bool
+	DataColumnsSubnets map[uint64]bool
+}
 
 const (
 	nodeInfoCacheSize   = 200
@@ -109,61 +81,6 @@ func Info(nodeID enode.ID, custodyGroupCount uint64) (*info, bool, error) {
 	return result, false, nil
 }
 
-// ActualGroupCount returns the actual custody group count.
-func (custodyInfo *CustodyInfo) ActualGroupCount() uint64 {
-	return min(custodyInfo.TargetGroupCount.Get(), custodyInfo.ToAdvertiseGroupCount.Get())
-}
-
-// CustodyGroupCount returns the number of groups we should participate in for custody.
-func (tcgc *targetCustodyGroupCount) Get() uint64 {
-	// If subscribed to all subnets, return the number of custody groups.
-	if flags.Get().SubscribeAllDataSubnets {
-		return params.BeaconConfig().NumberOfCustodyGroups
-	}
-
-	tcgc.mut.RLock()
-	defer tcgc.mut.RUnlock()
-
-	// If no validators are tracked, return the default custody requirement.
-	if tcgc.validatorsCustodyRequirement == 0 {
-		return params.BeaconConfig().CustodyRequirement
-	}
-
-	// Return the validators custody requirement.
-	return tcgc.validatorsCustodyRequirement
-}
-
-// setValidatorsCustodyRequirement sets the validators custody requirement.
-func (tcgc *targetCustodyGroupCount) SetValidatorsCustodyRequirement(value uint64) {
-	tcgc.mut.Lock()
-	defer tcgc.mut.Unlock()
-
-	tcgc.validatorsCustodyRequirement = value
-}
-
-// Get returns the to advertise custody group count.
-func (tacgc *toAdverstiseCustodyGroupCount) Get() uint64 {
-	// If subscribed to all subnets, return the number of custody groups.
-	if flags.Get().SubscribeAllDataSubnets {
-		return params.BeaconConfig().NumberOfCustodyGroups
-	}
-
-	custodyRequirement := params.BeaconConfig().CustodyRequirement
-
-	tacgc.mut.RLock()
-	defer tacgc.mut.RUnlock()
-
-	return max(tacgc.value, custodyRequirement)
-}
-
-// Set sets the to advertise custody group count.
-func (tacgc *toAdverstiseCustodyGroupCount) Set(value uint64) {
-	tacgc.mut.Lock()
-	defer tacgc.mut.Unlock()
-
-	tacgc.value = value
-}
-
 // createInfoCacheIfNeeded creates a new cache if it doesn't exist.
 func createInfoCacheIfNeeded() error {
 	nodeInfoCacheMut.Lock()

beacon-chain/core/peerdas/info_test.go

@@ -4,7 +4,6 @@ import (
 	"testing"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
-	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 )
@@ -26,108 +25,3 @@ func TestInfo(t *testing.T) {
 		require.DeepEqual(t, expectedDataColumnsSubnets, actual.DataColumnsSubnets)
 	}
 }
-
-func TestTargetCustodyGroupCount(t *testing.T) {
-	testCases := []struct {
-		name                         string
-		subscribeToAllColumns        bool
-		validatorsCustodyRequirement uint64
-		expected                     uint64
-	}{
-		{
-			name:                         "subscribed to all data subnets",
-			subscribeToAllColumns:        true,
-			validatorsCustodyRequirement: 100,
-			expected:                     128,
-		},
-		{
-			name:                         "no validators attached",
-			subscribeToAllColumns:        false,
-			validatorsCustodyRequirement: 0,
-			expected:                     4,
-		},
-		{
-			name:                         "some validators attached",
-			subscribeToAllColumns:        false,
-			validatorsCustodyRequirement: 100,
-			expected:                     100,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			// Subscribe to all subnets if needed.
-			if tc.subscribeToAllColumns {
-				resetFlags := flags.Get()
-				gFlags := new(flags.GlobalFlags)
-				gFlags.SubscribeAllDataSubnets = true
-				flags.Init(gFlags)
-				defer flags.Init(resetFlags)
-			}
-
-			var custodyInfo peerdas.CustodyInfo
-
-			// Set the validators custody requirement.
-			custodyInfo.TargetGroupCount.SetValidatorsCustodyRequirement(tc.validatorsCustodyRequirement)
-
-			// Get the target custody group count.
-			actual := custodyInfo.TargetGroupCount.Get()
-
-			// Compare the expected and actual values.
-			require.Equal(t, tc.expected, actual)
-		})
-	}
-}
-
-func TestToAdvertiseCustodyGroupCount(t *testing.T) {
-	testCases := []struct {
-		name                         string
-		subscribeToAllColumns        bool
-		toAdvertiseCustodyGroupCount uint64
-		expected                     uint64
-	}{
-		{
-			name:                         "subscribed to all subnets",
-			subscribeToAllColumns:        true,
-			toAdvertiseCustodyGroupCount: 100,
-			expected:                     128,
-		},
-		{
-			name:                         "higher than custody requirement",
-			subscribeToAllColumns:        false,
-			toAdvertiseCustodyGroupCount: 100,
-			expected:                     100,
-		},
-		{
-			name:                         "lower than custody requirement",
-			subscribeToAllColumns:        false,
-			toAdvertiseCustodyGroupCount: 1,
-			expected:                     4,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			// Subscribe to all subnets if needed.
-			if tc.subscribeToAllColumns {
-				resetFlags := flags.Get()
-				gFlags := new(flags.GlobalFlags)
-				gFlags.SubscribeAllDataSubnets = true
-				flags.Init(gFlags)
-				defer flags.Init(resetFlags)
-			}
-
-			// Create a custody info.
-			var custodyInfo peerdas.CustodyInfo
-
-			// Set the to advertise custody group count.
-			custodyInfo.ToAdvertiseGroupCount.Set(tc.toAdvertiseCustodyGroupCount)
-
-			// Get the to advertise custody group count.
-			actual := custodyInfo.ToAdvertiseGroupCount.Get()
-
-			// Compare the expected and actual values.
-			require.Equal(t, tc.expected, actual)
-		})
-	}
-}

beacon-chain/core/peerdas/p2p_interface.go

@@ -10,10 +10,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-const (
-	CustodyGroupCountEnrKey = "cgc"
-	kzgPosition             = 11 // The index of the KZG commitment list in the Body
-)
+const kzgPosition = 11 // The index of the KZG commitment list in the Body
 
 var (
 	ErrIndexTooLarge               = errors.New("column index is larger than the specified columns count")
@@ -27,13 +24,13 @@ var (
 	ErrCannotLoadCustodyGroupCount = errors.New("cannot load the custody group count from peer")
 )
 
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/p2p-interface.md#custody-group-count
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#custody-group-count
 type Cgc uint64
 
-func (Cgc) ENRKey() string { return CustodyGroupCountEnrKey }
+func (Cgc) ENRKey() string { return params.BeaconNetworkConfig().CustodyGroupCountKey }
 
 // VerifyDataColumnSidecar verifies if the data column sidecar is valid.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/p2p-interface.md#verify_data_column_sidecar
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#verify_data_column_sidecar
 func VerifyDataColumnSidecar(sidecar blocks.RODataColumn) error {
 	// The sidecar index must be within the valid range.
 	numberOfColumns := params.BeaconConfig().NumberOfColumns
@@ -60,7 +57,7 @@ func VerifyDataColumnSidecar(sidecar blocks.RODataColumn) error {
 // while we are verifying all the KZG proofs from multiple sidecars in a batch.
 // This is done to improve performance since the internal KZG library is way more
 // efficient when verifying in batch.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/p2p-interface.md#verify_data_column_sidecar_kzg_proofs
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#verify_data_column_sidecar_kzg_proofs
 func VerifyDataColumnsSidecarKZGProofs(sidecars []blocks.RODataColumn) error {
 	// Compute the total count.
 	count := 0
@@ -96,7 +93,7 @@ func VerifyDataColumnsSidecarKZGProofs(sidecars []blocks.RODataColumn) error {
 }
 
 // VerifyDataColumnSidecarInclusionProof verifies if the given KZG commitments included in the given beacon block.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/p2p-interface.md#verify_data_column_sidecar_inclusion_proof
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#verify_data_column_sidecar_inclusion_proof
 func VerifyDataColumnSidecarInclusionProof(sidecar blocks.RODataColumn) error {
 	if sidecar.SignedBlockHeader == nil || sidecar.SignedBlockHeader.Header == nil {
 		return ErrNilBlockHeader
@@ -128,7 +125,7 @@ func VerifyDataColumnSidecarInclusionProof(sidecar blocks.RODataColumn) error {
 }
 
 // ComputeSubnetForDataColumnSidecar computes the subnet for a data column sidecar.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/p2p-interface.md#compute_subnet_for_data_column_sidecar
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#compute_subnet_for_data_column_sidecar
 func ComputeSubnetForDataColumnSidecar(columnIndex uint64) uint64 {
 	dataColumnSidecarSubnetCount := params.BeaconConfig().DataColumnSidecarSubnetCount
 	return columnIndex % dataColumnSidecarSubnetCount

beacon-chain/core/peerdas/validator.go

@@ -8,7 +8,7 @@ import (
 )
 
 // ValidatorsCustodyRequirement returns the number of custody groups regarding the validator indices attached to the beacon node.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/validator.md#validator-custody
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#validator-custody
 func ValidatorsCustodyRequirement(state beaconState.ReadOnlyBeaconState, validatorsIndex map[primitives.ValidatorIndex]bool) (uint64, error) {
 	totalNodeBalance := uint64(0)
 	for index := range validatorsIndex {

beacon-chain/das/BUILD.bazel

@@ -39,10 +39,8 @@ go_test(
     ],
     embed = [":go_default_library"],
     deps = [
-        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/verification:go_default_library",
-        "//cmd/beacon-chain/flags:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",

beacon-chain/das/availability_columns.go

@@ -22,8 +22,8 @@ type LazilyPersistentStoreColumn struct {
 	store                  *filesystem.DataColumnStorage
 	nodeID                 enode.ID
 	cache                  *dataColumnCache
-	custodyInfo            *peerdas.CustodyInfo
 	newDataColumnsVerifier verification.NewDataColumnsVerifier
+	custodyGroupCount      uint64
 }
 
 var _ AvailabilityStore = &LazilyPersistentStoreColumn{}
@@ -38,13 +38,18 @@ type DataColumnsVerifier interface {
 
 // NewLazilyPersistentStoreColumn creates a new LazilyPersistentStoreColumn.
 // WARNING: The resulting LazilyPersistentStoreColumn is NOT thread-safe.
-func NewLazilyPersistentStoreColumn(store *filesystem.DataColumnStorage, nodeID enode.ID, newDataColumnsVerifier verification.NewDataColumnsVerifier, custodyInfo *peerdas.CustodyInfo) *LazilyPersistentStoreColumn {
+func NewLazilyPersistentStoreColumn(
+	store *filesystem.DataColumnStorage,
+	nodeID enode.ID,
+	newDataColumnsVerifier verification.NewDataColumnsVerifier,
+	custodyGroupCount uint64,
+) *LazilyPersistentStoreColumn {
 	return &LazilyPersistentStoreColumn{
 		store:                  store,
 		nodeID:                 nodeID,
 		cache:                  newDataColumnCache(),
-		custodyInfo:            custodyInfo,
 		newDataColumnsVerifier: newDataColumnsVerifier,
+		custodyGroupCount:      custodyGroupCount,
 	}
 }
 
@@ -155,6 +160,8 @@ func (s *LazilyPersistentStoreColumn) IsDataAvailable(ctx context.Context, curre
 
 // fullCommitmentsToCheck returns the commitments to check for a given block.
 func (s *LazilyPersistentStoreColumn) fullCommitmentsToCheck(nodeID enode.ID, block blocks.ROBlock, currentSlot primitives.Slot) (*safeCommitmentsArray, error) {
+	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
+
 	// Return early for blocks that are pre-Fulu.
 	if block.Version() < version.Fulu {
 		return &safeCommitmentsArray{}, nil
@@ -183,11 +190,9 @@ func (s *LazilyPersistentStoreColumn) fullCommitmentsToCheck(nodeID enode.ID, bl
 		return &safeCommitmentsArray{}, nil
 	}
 
-	// Retrieve the groups count.
-	custodyGroupCount := s.custodyInfo.ActualGroupCount()
-
 	// Retrieve peer info.
-	peerInfo, _, err := peerdas.Info(nodeID, custodyGroupCount)
+	samplingSize := max(s.custodyGroupCount, samplesPerSlot)
+	peerInfo, _, err := peerdas.Info(nodeID, samplingSize)
 	if err != nil {
 		return nil, errors.Wrap(err, "peer info")
 	}

beacon-chain/das/availability_columns_test.go

@@ -4,10 +4,8 @@ import (
 	"context"
 	"testing"
 
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
-	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
@@ -29,7 +27,7 @@ var commitments = [][]byte{
 func TestPersist(t *testing.T) {
 	t.Run("no sidecars", func(t *testing.T) {
 		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, &peerdas.CustodyInfo{})
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
 		err := lazilyPersistentStoreColumns.Persist(0)
 		require.NoError(t, err)
 		require.Equal(t, 0, len(lazilyPersistentStoreColumns.cache.entries))
@@ -44,7 +42,7 @@ func TestPersist(t *testing.T) {
 		}
 
 		roSidecars, _ := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, &peerdas.CustodyInfo{})
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
 
 		err := lazilyPersistentStoreColumns.Persist(0, roSidecars...)
 		require.ErrorIs(t, err, errMixedRoots)
@@ -59,7 +57,7 @@ func TestPersist(t *testing.T) {
 		}
 
 		roSidecars, _ := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, &peerdas.CustodyInfo{})
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
 
 		err := lazilyPersistentStoreColumns.Persist(1_000_000, roSidecars...)
 		require.NoError(t, err)
@@ -76,7 +74,7 @@ func TestPersist(t *testing.T) {
 		}
 
 		roSidecars, roDataColumns := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, &peerdas.CustodyInfo{})
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
 
 		err := lazilyPersistentStoreColumns.Persist(slot, roSidecars...)
 		require.NoError(t, err)
@@ -114,7 +112,7 @@ func TestIsDataAvailable(t *testing.T) {
 		signedRoBlock := newSignedRoBlock(t, signedBeaconBlockFulu)
 
 		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, newDataColumnsVerifier, &peerdas.CustodyInfo{})
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, newDataColumnsVerifier, 0)
 
 		err := lazilyPersistentStoreColumns.IsDataAvailable(ctx, 0 /*current slot*/, signedRoBlock)
 		require.NoError(t, err)
@@ -135,9 +133,9 @@ func TestIsDataAvailable(t *testing.T) {
 		root := signedRoBlock.Root()
 
 		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, newDataColumnsVerifier, &peerdas.CustodyInfo{})
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, newDataColumnsVerifier, 0)
 
-		indices := [...]uint64{1, 17, 87, 102}
+		indices := [...]uint64{1, 17, 19, 42, 75, 87, 102, 117}
 		dataColumnsParams := make([]util.DataColumnParam, 0, len(indices))
 		for _, index := range indices {
 			dataColumnParams := util.DataColumnParam{
@@ -221,14 +219,10 @@ func TestFullCommitmentsToCheck(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			resetFlags := flags.Get()
-			gFlags := new(flags.GlobalFlags)
-			gFlags.SubscribeAllDataSubnets = true
-			flags.Init(gFlags)
-			defer flags.Init(resetFlags)
+			numberOfColumns := params.BeaconConfig().NumberOfColumns
 
 			b := tc.block(t)
-			s := NewLazilyPersistentStoreColumn(nil, enode.ID{}, nil, &peerdas.CustodyInfo{})
+			s := NewLazilyPersistentStoreColumn(nil, enode.ID{}, nil, numberOfColumns)
 
 			commitmentsArray, err := s.fullCommitmentsToCheck(enode.ID{}, b, tc.slot)
 			require.NoError(t, err)

beacon-chain/db/iface/interface.go

@@ -33,6 +33,7 @@ type ReadOnlyDatabase interface {
 	IsFinalizedBlock(ctx context.Context, blockRoot [32]byte) bool
 	FinalizedChildBlock(ctx context.Context, blockRoot [32]byte) (interfaces.ReadOnlySignedBeaconBlock, error)
 	HighestRootsBelowSlot(ctx context.Context, slot primitives.Slot) (primitives.Slot, [][32]byte, error)
+	EarliestSlot(ctx context.Context) (primitives.Slot, error)
 	// State related methods.
 	State(ctx context.Context, blockRoot [32]byte) (state.BeaconState, error)
 	StateOrError(ctx context.Context, blockRoot [32]byte) (state.BeaconState, error)
@@ -56,12 +57,11 @@ type ReadOnlyDatabase interface {
 	// Fee recipients operations.
 	FeeRecipientByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (common.Address, error)
 	RegistrationByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (*ethpb.ValidatorRegistrationV1, error)
-	// light client operations
+	// Light client operations
 	LightClientUpdates(ctx context.Context, startPeriod, endPeriod uint64) (map[uint64]interfaces.LightClientUpdate, error)
 	LightClientUpdate(ctx context.Context, period uint64) (interfaces.LightClientUpdate, error)
 	LightClientBootstrap(ctx context.Context, blockRoot []byte) (interfaces.LightClientBootstrap, error)
-
-	// origin checkpoint sync support
+	// Origin checkpoint sync support
 	OriginCheckpointBlockRoot(ctx context.Context) ([32]byte, error)
 	BackfillStatus(context.Context) (*dbval.BackfillStatus, error)
 }
@@ -102,6 +102,10 @@ type NoHeadAccessDatabase interface {
 
 	CleanUpDirtyStates(ctx context.Context, slotsPerArchivedPoint primitives.Slot) error
 	DeleteHistoricalDataBeforeSlot(ctx context.Context, slot primitives.Slot, batchSize int) (int, error)
+
+	// Custody operations.
+	UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed bool) (bool, error)
+	UpdateCustodyInfo(ctx context.Context, earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error)
 }
 
 // HeadAccessDatabase defines a struct with access to reading chain head data.

beacon-chain/db/kv/BUILD.bazel

@@ -8,6 +8,7 @@ go_library(
         "backup.go",
         "blocks.go",
         "checkpoint.go",
+        "custody.go",
         "deposit_contract.go",
         "encoding.go",
         "error.go",
@@ -83,6 +84,7 @@ go_test(
         "backup_test.go",
         "blocks_test.go",
         "checkpoint_test.go",
+        "custody_test.go",
         "deposit_contract_test.go",
         "encoding_test.go",
         "execution_chain_test.go",

beacon-chain/db/kv/blocks.go

@@ -860,6 +860,47 @@ func (s *Store) SaveRegistrationsByValidatorIDs(ctx context.Context, ids []primi
 	})
 }
 
+// EarliestStoredSlot returns the earliest slot in the database.
+func (s *Store) EarliestSlot(ctx context.Context) (primitives.Slot, error) {
+	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+	_, span := trace.StartSpan(ctx, "BeaconDB.EarliestSlot")
+	defer span.End()
+
+	earliestAvailableSlot := primitives.Slot(0)
+	err := s.db.View(func(tx *bolt.Tx) error {
+		// Retrieve the root corresponding to the earliest available block.
+		c := tx.Bucket(blockSlotIndicesBucket).Cursor()
+		k, v := c.First()
+		if k == nil || v == nil {
+			return ErrNotFound
+		}
+		slot := bytesutil.BytesToSlotBigEndian(k)
+
+		// The genesis block may be indexed in this bucket, even if we started from a checkpoint.
+		// Because of this, we check the next block. If the next block is still in the genesis epoch,
+		// then we consider we have the whole chain.
+		if slot != 0 {
+			earliestAvailableSlot = slot
+		}
+
+		k, v = c.Next()
+		if k == nil || v == nil {
+			// Only the genesis block is available.
+			return nil
+		}
+		slot = bytesutil.BytesToSlotBigEndian(k)
+		if slot < slotsPerEpoch {
+			// We are still in the genesis epoch, so we consider we have the whole chain.
+			return nil
+		}
+
+		earliestAvailableSlot = slot
+		return nil
+	})
+
+	return earliestAvailableSlot, err
+}
+
 type slotRoot struct {
 	slot primitives.Slot
 	root [32]byte
@@ -883,7 +924,7 @@ func (s *Store) slotRootsInRange(ctx context.Context, start, end primitives.Slot
 		c := bkt.Cursor()
 		for k, v := c.Seek(key); ; /* rely on internal checks to exit */ k, v = c.Prev() {
 			if len(k) == 0 && len(v) == 0 {
-				// The `edge`` variable and this `if` deal with 2 edge cases:
+				// The `edge` variable and this `if` deal with 2 edge cases:
 				// - Seeking past the end of the bucket (the `end` param is higher than the highest slot).
 				// - Seeking before the beginning of the bucket (the `start` param is lower than the lowest slot).
 				// In both of these cases k,v will be nil and we can handle the same way using `edge` to

beacon-chain/db/kv/blocks_test.go

@@ -1,6 +1,7 @@
 package kv
 
 import (
+	"context"
 	"fmt"
 	"testing"
 	"time"
@@ -1327,3 +1328,86 @@ func TestStore_RegistrationsByValidatorID(t *testing.T) {
 	want := errors.Wrap(ErrNotFoundFeeRecipient, "validator id 3")
 	require.Equal(t, want.Error(), err.Error())
 }
+
+// Block creates a phase0 beacon block at the specified slot and saves it to the database.
+func createAndSaveBlock(t *testing.T, ctx context.Context, db *Store, slot primitives.Slot) {
+	block := util.NewBeaconBlock()
+	block.Block.Slot = slot
+
+	wrappedBlock, err := blocks.NewSignedBeaconBlock(block)
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(ctx, wrappedBlock))
+}
+
+func TestStore_EarliestSlot(t *testing.T) {
+	ctx := t.Context()
+
+	t.Run("empty database returns ErrNotFound", func(t *testing.T) {
+		db := setupDB(t)
+
+		slot, err := db.EarliestSlot(ctx)
+		require.ErrorIs(t, err, ErrNotFound)
+		assert.Equal(t, primitives.Slot(0), slot)
+	})
+
+	t.Run("database with only genesis block", func(t *testing.T) {
+		db := setupDB(t)
+
+		// Create and save genesis block (slot 0)
+		createAndSaveBlock(t, ctx, db, 0)
+
+		slot, err := db.EarliestSlot(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, primitives.Slot(0), slot)
+	})
+
+	t.Run("database with genesis and blocks in genesis epoch", func(t *testing.T) {
+		db := setupDB(t)
+		slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+
+		// Create and save genesis block (slot 0)
+		createAndSaveBlock(t, ctx, db, 0)
+
+		// Create and save a block in the genesis epoch
+		createAndSaveBlock(t, ctx, db, primitives.Slot(slotsPerEpoch-1))
+
+		slot, err := db.EarliestSlot(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, primitives.Slot(0), slot)
+	})
+
+	t.Run("database with genesis and blocks beyond genesis epoch", func(t *testing.T) {
+		db := setupDB(t)
+		slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+
+		// Create and save genesis block (slot 0)
+		createAndSaveBlock(t, ctx, db, 0)
+
+		// Create and save a block beyond the genesis epoch
+		nextEpochSlot := primitives.Slot(slotsPerEpoch)
+		createAndSaveBlock(t, ctx, db, nextEpochSlot)
+
+		slot, err := db.EarliestSlot(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, nextEpochSlot, slot)
+	})
+
+	t.Run("database starting from checkpoint (non-zero earliest slot)", func(t *testing.T) {
+		db := setupDB(t)
+		slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+
+		// Simulate starting from a checkpoint by creating blocks starting from a later slot
+		checkpointSlot := primitives.Slot(slotsPerEpoch * 10) // 10 epochs later
+		nextEpochSlot := checkpointSlot + slotsPerEpoch
+
+		// Create and save first block at checkpoint slot
+		createAndSaveBlock(t, ctx, db, checkpointSlot)
+
+		// Create and save another block in the next epoch
+		createAndSaveBlock(t, ctx, db, nextEpochSlot)
+
+		slot, err := db.EarliestSlot(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, nextEpochSlot, slot)
+	})
+}

beacon-chain/db/kv/custody.go

@@ -0,0 +1,129 @@
+package kv
+
+import (
+	"context"
+
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/monitoring/tracing/trace"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	bolt "go.etcd.io/bbolt"
+)
+
+// UpdateCustodyInfo atomically updates the custody group count only it is greater than the stored one.
+// In this case, it also updates the earliest available slot with the provided value.
+// It returns the (potentially updated) custody group count and earliest available slot.
+func (s *Store) UpdateCustodyInfo(ctx context.Context, earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error) {
+	_, span := trace.StartSpan(ctx, "BeaconDB.UpdateCustodyInfo")
+	defer span.End()
+
+	storedGroupCount, storedEarliestAvailableSlot := uint64(0), primitives.Slot(0)
+	if err := s.db.Update(func(tx *bolt.Tx) error {
+		// Retrieve the custody bucket.
+		bucket, err := tx.CreateBucketIfNotExists(custodyBucket)
+		if err != nil {
+			return errors.Wrap(err, "create custody bucket")
+		}
+
+		// Retrieve the stored custody group count.
+		storedGroupCountBytes := bucket.Get(groupCountKey)
+		if len(storedGroupCountBytes) != 0 {
+			storedGroupCount = bytesutil.BytesToUint64BigEndian(storedGroupCountBytes)
+		}
+
+		// Retrieve the stored earliest available slot.
+		storedEarliestAvailableSlotBytes := bucket.Get(earliestAvailableSlotKey)
+		if len(storedEarliestAvailableSlotBytes) != 0 {
+			storedEarliestAvailableSlot = primitives.Slot(bytesutil.BytesToUint64BigEndian(storedEarliestAvailableSlotBytes))
+		}
+
+		// Exit early if the new custody group count is lower than or equal to the stored one.
+		if custodyGroupCount <= storedGroupCount {
+			return nil
+		}
+
+		storedGroupCount, storedEarliestAvailableSlot = custodyGroupCount, earliestAvailableSlot
+
+		// Store the earliest available slot.
+		bytes := bytesutil.Uint64ToBytesBigEndian(uint64(earliestAvailableSlot))
+		if err := bucket.Put(earliestAvailableSlotKey, bytes); err != nil {
+			return errors.Wrap(err, "put earliest available slot")
+		}
+
+		// Store the custody group count.
+		bytes = bytesutil.Uint64ToBytesBigEndian(custodyGroupCount)
+		if err := bucket.Put(groupCountKey, bytes); err != nil {
+			return errors.Wrap(err, "put custody group count")
+		}
+
+		return nil
+	}); err != nil {
+		return 0, 0, err
+	}
+
+	log.WithFields(logrus.Fields{
+		"earliestAvailableSlot": storedEarliestAvailableSlot,
+		"groupCount":            storedGroupCount,
+	}).Debug("Custody info")
+
+	return storedEarliestAvailableSlot, storedGroupCount, nil
+}
+
+// UpdateSubscribedToAllDataSubnets updates the "subscribed to all data subnets" status in the database
+// only if `subscribed` is `true`.
+// It returns the previous subscription status.
+func (s *Store) UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed bool) (bool, error) {
+	_, span := trace.StartSpan(ctx, "BeaconDB.UpdateSubscribedToAllDataSubnets")
+	defer span.End()
+
+	result := false
+	if !subscribed {
+		if err := s.db.View(func(tx *bolt.Tx) error {
+			// Retrieve the custody bucket.
+			bucket := tx.Bucket(custodyBucket)
+			if bucket == nil {
+				return nil
+			}
+
+			// Retrieve the subscribe all data subnets flag.
+			bytes := bucket.Get(subscribeAllDataSubnetsKey)
+			if len(bytes) == 0 {
+				return nil
+			}
+
+			if bytes[0] == 1 {
+				result = true
+			}
+
+			return nil
+		}); err != nil {
+			return false, err
+		}
+
+		return result, nil
+	}
+
+	if err := s.db.Update(func(tx *bolt.Tx) error {
+		// Retrieve the custody bucket.
+		bucket, err := tx.CreateBucketIfNotExists(custodyBucket)
+		if err != nil {
+			return errors.Wrap(err, "create custody bucket")
+		}
+
+		bytes := bucket.Get(subscribeAllDataSubnetsKey)
+		if len(bytes) != 0 && bytes[0] == 1 {
+			result = true
+		}
+
+		if err := bucket.Put(subscribeAllDataSubnetsKey, []byte{1}); err != nil {
+			return errors.Wrap(err, "put subscribe all data subnets")
+		}
+
+		return nil
+	}); err != nil {
+		return false, err
+	}
+
+	return result, nil
+}

beacon-chain/db/kv/custody_test.go

@@ -0,0 +1,176 @@
+package kv
+
+import (
+	"context"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+	bolt "go.etcd.io/bbolt"
+)
+
+// getCustodyInfoFromDB reads the custody info directly from the database for testing purposes.
+func getCustodyInfoFromDB(t *testing.T, db *Store) (primitives.Slot, uint64) {
+	t.Helper()
+	var earliestSlot primitives.Slot
+	var groupCount uint64
+
+	err := db.db.View(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(custodyBucket)
+		if bucket == nil {
+			return nil
+		}
+
+		// Read group count
+		groupCountBytes := bucket.Get(groupCountKey)
+		if len(groupCountBytes) != 0 {
+			groupCount = bytesutil.BytesToUint64BigEndian(groupCountBytes)
+		}
+
+		// Read earliest available slot
+		earliestSlotBytes := bucket.Get(earliestAvailableSlotKey)
+		if len(earliestSlotBytes) != 0 {
+			earliestSlot = primitives.Slot(bytesutil.BytesToUint64BigEndian(earliestSlotBytes))
+		}
+
+		return nil
+	})
+	require.NoError(t, err)
+
+	return earliestSlot, groupCount
+}
+
+// getSubscriptionStatusFromDB reads the subscription status directly from the database for testing purposes.
+func getSubscriptionStatusFromDB(t *testing.T, db *Store) bool {
+	t.Helper()
+	var subscribed bool
+
+	err := db.db.View(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(custodyBucket)
+		if bucket == nil {
+			return nil
+		}
+
+		bytes := bucket.Get(subscribeAllDataSubnetsKey)
+		if len(bytes) != 0 && bytes[0] == 1 {
+			subscribed = true
+		}
+
+		return nil
+	})
+	require.NoError(t, err)
+
+	return subscribed
+}
+
+func TestUpdateCustodyInfo(t *testing.T) {
+	ctx := t.Context()
+
+	t.Run("initial update with empty database", func(t *testing.T) {
+		const (
+			earliestSlot = primitives.Slot(100)
+			groupCount   = uint64(5)
+		)
+
+		db := setupDB(t)
+
+		slot, count, err := db.UpdateCustodyInfo(ctx, earliestSlot, groupCount)
+		require.NoError(t, err)
+		require.Equal(t, earliestSlot, slot)
+		require.Equal(t, groupCount, count)
+
+		storedSlot, storedCount := getCustodyInfoFromDB(t, db)
+		require.Equal(t, earliestSlot, storedSlot)
+		require.Equal(t, groupCount, storedCount)
+	})
+
+	t.Run("update with higher group count", func(t *testing.T) {
+		const (
+			initialSlot  = primitives.Slot(100)
+			initialCount = uint64(5)
+			earliestSlot = primitives.Slot(200)
+			groupCount   = uint64(10)
+		)
+
+		db := setupDB(t)
+
+		_, _, err := db.UpdateCustodyInfo(ctx, initialSlot, initialCount)
+		require.NoError(t, err)
+
+		slot, count, err := db.UpdateCustodyInfo(ctx, earliestSlot, groupCount)
+		require.NoError(t, err)
+		require.Equal(t, earliestSlot, slot)
+		require.Equal(t, groupCount, count)
+
+		storedSlot, storedCount := getCustodyInfoFromDB(t, db)
+		require.Equal(t, earliestSlot, storedSlot)
+		require.Equal(t, groupCount, storedCount)
+	})
+
+	t.Run("update with lower group count should not update", func(t *testing.T) {
+		const (
+			initialSlot  = primitives.Slot(200)
+			initialCount = uint64(10)
+			earliestSlot = primitives.Slot(300)
+			groupCount   = uint64(8)
+		)
+
+		db := setupDB(t)
+
+		_, _, err := db.UpdateCustodyInfo(ctx, initialSlot, initialCount)
+		require.NoError(t, err)
+
+		slot, count, err := db.UpdateCustodyInfo(ctx, earliestSlot, groupCount)
+		require.NoError(t, err)
+		require.Equal(t, initialSlot, slot)
+		require.Equal(t, initialCount, count)
+
+		storedSlot, storedCount := getCustodyInfoFromDB(t, db)
+		require.Equal(t, initialSlot, storedSlot)
+		require.Equal(t, initialCount, storedCount)
+	})
+}
+
+func TestUpdateSubscribedToAllDataSubnets(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("initial update with empty database - set to false", func(t *testing.T) {
+		db := setupDB(t)
+
+		prev, err := db.UpdateSubscribedToAllDataSubnets(ctx, false)
+		require.NoError(t, err)
+		require.Equal(t, false, prev)
+
+		stored := getSubscriptionStatusFromDB(t, db)
+		require.Equal(t, false, stored)
+	})
+
+	t.Run("attempt to update from true to false (should not change)", func(t *testing.T) {
+		db := setupDB(t)
+
+		_, err := db.UpdateSubscribedToAllDataSubnets(ctx, true)
+		require.NoError(t, err)
+
+		prev, err := db.UpdateSubscribedToAllDataSubnets(ctx, false)
+		require.NoError(t, err)
+		require.Equal(t, true, prev)
+
+		stored := getSubscriptionStatusFromDB(t, db)
+		require.Equal(t, true, stored)
+	})
+
+	t.Run("attempt to update from true to false (should not change)", func(t *testing.T) {
+		db := setupDB(t)
+
+		_, err := db.UpdateSubscribedToAllDataSubnets(ctx, true)
+		require.NoError(t, err)
+
+		prev, err := db.UpdateSubscribedToAllDataSubnets(ctx, true)
+		require.NoError(t, err)
+		require.Equal(t, true, prev)
+
+		stored := getSubscriptionStatusFromDB(t, db)
+		require.Equal(t, true, stored)
+	})
+}

beacon-chain/db/kv/kv.go

@@ -123,6 +123,7 @@ var Buckets = [][]byte{
 
 	feeRecipientBucket,
 	registrationBucket,
+	custodyBucket,
 }
 
 // KVStoreOption is a functional option that modifies a kv.Store.

beacon-chain/db/kv/schema.go

@@ -70,4 +70,10 @@ var (
 
 	// Migrations
 	migrationsBucket = []byte("migrations")
+
+	// Custody
+	custodyBucket              = []byte("custody")
+	groupCountKey              = []byte("group-count")
+	earliestAvailableSlotKey   = []byte("earliest-available-slot")
+	subscribeAllDataSubnetsKey = []byte("subscribe-all-data-subnets")
 )

beacon-chain/db/kv/wss.go

@@ -43,6 +43,7 @@ func (s *Store) SaveOrigin(ctx context.Context, serState, serBlock []byte) error
 		return errors.Wrap(err, "failed to initialize origin block w/ bytes + config+fork")
 	}
 	blk := wblk.Block()
+	slot := blk.Slot()
 
 	blockRoot, err := blk.HashTreeRoot()
 	if err != nil {
@@ -51,43 +52,43 @@ func (s *Store) SaveOrigin(ctx context.Context, serState, serBlock []byte) error
 
 	pr := blk.ParentRoot()
 	bf := &dbval.BackfillStatus{
-		LowSlot:       uint64(wblk.Block().Slot()),
+		LowSlot:       uint64(slot),
 		LowRoot:       blockRoot[:],
 		LowParentRoot: pr[:],
 		OriginRoot:    blockRoot[:],
-		OriginSlot:    uint64(wblk.Block().Slot()),
+		OriginSlot:    uint64(slot),
 	}
 
 	if err = s.SaveBackfillStatus(ctx, bf); err != nil {
 		return errors.Wrap(err, "unable to save backfill status data to db for checkpoint sync")
 	}
 
-	log.WithField("root", fmt.Sprintf("%#x", blockRoot)).Info("Saving checkpoint block to db")
+	log.WithField("root", fmt.Sprintf("%#x", blockRoot)).Info("Saving checkpoint data into database")
 	if err := s.SaveBlock(ctx, wblk); err != nil {
-		return errors.Wrap(err, "could not save checkpoint block")
+		return errors.Wrap(err, "save block")
 	}
 
 	// save state
-	log.WithField("blockRoot", fmt.Sprintf("%#x", blockRoot)).Info("Calling SaveState")
 	if err = s.SaveState(ctx, state, blockRoot); err != nil {
-		return errors.Wrap(err, "could not save state")
+		return errors.Wrap(err, "save state")
 	}
+
 	if err = s.SaveStateSummary(ctx, &ethpb.StateSummary{
 		Slot: state.Slot(),
 		Root: blockRoot[:],
 	}); err != nil {
-		return errors.Wrap(err, "could not save state summary")
+		return errors.Wrap(err, "save state summary")
 	}
 
 	// mark block as head of chain, so that processing will pick up from this point
 	if err = s.SaveHeadBlockRoot(ctx, blockRoot); err != nil {
-		return errors.Wrap(err, "could not save head block root")
+		return errors.Wrap(err, "save head block root")
 	}
 
 	// save origin block root in a special key, to be used when the canonical
 	// origin (start of chain, ie alternative to genesis) block or state is needed
 	if err = s.SaveOriginCheckpointBlockRoot(ctx, blockRoot); err != nil {
-		return errors.Wrap(err, "could not save origin block root")
+		return errors.Wrap(err, "save origin checkpoint block root")
 	}
 
 	// rebuild the checkpoint from the block
@@ -96,15 +97,18 @@ func (s *Store) SaveOrigin(ctx context.Context, serState, serBlock []byte) error
 	if err != nil {
 		return err
 	}
+
 	chkpt := &ethpb.Checkpoint{
 		Epoch: primitives.Epoch(slotEpoch),
 		Root:  blockRoot[:],
 	}
+
 	if err = s.SaveJustifiedCheckpoint(ctx, chkpt); err != nil {
-		return errors.Wrap(err, "could not mark checkpoint sync block as justified")
+		return errors.Wrap(err, "save justified checkpoint")
 	}
+
 	if err = s.SaveFinalizedCheckpoint(ctx, chkpt); err != nil {
-		return errors.Wrap(err, "could not mark checkpoint sync block as finalized")
+		return errors.Wrap(err, "save finalized checkpoint")
 	}
 
 	return nil

beacon-chain/node/BUILD.bazel

@@ -23,7 +23,6 @@ go_library(
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/cache/depositsnapshot:go_default_library",
         "//beacon-chain/core/light-client:go_default_library",
-        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/db/kv:go_default_library",

beacon-chain/node/node.go

@@ -26,7 +26,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache/depositsnapshot"
 	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/kv"
@@ -124,7 +123,6 @@ type BeaconNode struct {
 	BlobStorageOptions       []filesystem.BlobStorageOption
 	DataColumnStorage        *filesystem.DataColumnStorage
 	DataColumnStorageOptions []filesystem.DataColumnStorageOption
-	custodyInfo              *peerdas.CustodyInfo
 	verifyInitWaiter         *verification.InitializerWaiter
 	syncChecker              *initialsync.SyncChecker
 	slasherEnabled           bool
@@ -166,7 +164,6 @@ func New(cliCtx *cli.Context, cancel context.CancelFunc, opts ...Option) (*Beaco
 		serviceFlagOpts:         &serviceFlagOpts{},
 		initialSyncComplete:     make(chan struct{}),
 		syncChecker:             &initialsync.SyncChecker{},
-		custodyInfo:             &peerdas.CustodyInfo{},
 		slasherEnabled:          cliCtx.Bool(flags.SlasherFlag.Name),
 	}
 
@@ -236,7 +233,7 @@ func New(cliCtx *cli.Context, cancel context.CancelFunc, opts ...Option) (*Beaco
 	beacon.finalizedStateAtStartUp = nil
 
 	if features.Get().EnableLightClient {
-		beacon.lcStore = lightclient.NewLightClientStore(beacon.db)
+		beacon.lcStore = lightclient.NewLightClientStore(beacon.db, beacon.fetchP2P(), beacon.StateFeed())
 	}
 
 	return beacon, nil
@@ -717,7 +714,6 @@ func (b *BeaconNode) registerP2P(cliCtx *cli.Context) error {
 		StateNotifier:        b,
 		DB:                   b.db,
 		ClockWaiter:          b.clockWaiter,
-		CustodyInfo:          b.custodyInfo,
 	})
 	if err != nil {
 		return err
@@ -800,7 +796,6 @@ func (b *BeaconNode) registerBlockchainService(fc forkchoice.ForkChoicer, gs *st
 		blockchain.WithTrackedValidatorsCache(b.trackedValidatorsCache),
 		blockchain.WithPayloadIDCache(b.payloadIDCache),
 		blockchain.WithSyncChecker(b.syncChecker),
-		blockchain.WithCustodyInfo(b.custodyInfo),
 		blockchain.WithSlasherEnabled(b.slasherEnabled),
 		blockchain.WithLightClientStore(b.lcStore),
 	)
@@ -888,7 +883,7 @@ func (b *BeaconNode) registerSyncService(initialSyncComplete chan struct{}, bFil
 		regularsync.WithDataColumnStorage(b.DataColumnStorage),
 		regularsync.WithVerifierWaiter(b.verifyInitWaiter),
 		regularsync.WithAvailableBlocker(bFillStore),
-		regularsync.WithCustodyInfo(b.custodyInfo),
+		regularsync.WithTrackedValidatorsCache(b.trackedValidatorsCache),
 		regularsync.WithSlasherEnabled(b.slasherEnabled),
 		regularsync.WithLightClientStore(b.lcStore),
 		regularsync.WithBatchVerifierLimit(b.cliCtx.Int(flags.BatchVerifierLimit.Name)),

beacon-chain/p2p/BUILD.bazel

@@ -147,7 +147,6 @@ go_test(
         "//beacon-chain/blockchain/testing:go_default_library",
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/db/testing:go_default_library",
@@ -174,7 +173,6 @@ go_test(
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/metadata:go_default_library",
         "//proto/testing:go_default_library",
-        "//runtime/version:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",

beacon-chain/p2p/broadcaster_test.go

@@ -11,7 +11,6 @@ import (
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
-	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/scorers"
@@ -24,7 +23,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/network/forks"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	testpb "github.com/OffchainLabs/prysm/v6/proto/testing"
-	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/testing/assert"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
@@ -229,6 +227,7 @@ func TestService_BroadcastAttestationWithDiscoveryAttempts(t *testing.T) {
 		cfg:                   cfg,
 		genesisTime:           genesisTime,
 		genesisValidatorsRoot: genesisValidatorsRoot,
+		custodyInfo:           &custodyInfo{},
 	}
 	bootListener, err := s.createListener(ipAddr, pkey)
 	require.NoError(t, err)
@@ -257,6 +256,7 @@ func TestService_BroadcastAttestationWithDiscoveryAttempts(t *testing.T) {
 			cfg:                   cfg,
 			genesisTime:           genesisTime,
 			genesisValidatorsRoot: genesisValidatorsRoot,
+			custodyInfo:           &custodyInfo{},
 		}
 		listener, err := s.startDiscoveryV5(ipAddr, pkey)
 		// Set for 2nd peer
@@ -546,8 +546,7 @@ func TestService_BroadcastLightClientOptimisticUpdate(t *testing.T) {
 		}),
 	}
 
-	l := util.NewTestLightClient(t, version.Altair)
-	msg, err := lightClient.NewLightClientOptimisticUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock)
+	msg, err := util.MockOptimisticUpdate()
 	require.NoError(t, err)
 
 	GossipTypeMapping[reflect.TypeOf(msg)] = LightClientOptimisticUpdateTopicFormat
@@ -613,8 +612,7 @@ func TestService_BroadcastLightClientFinalityUpdate(t *testing.T) {
 		}),
 	}
 
-	l := util.NewTestLightClient(t, version.Altair)
-	msg, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+	msg, err := util.MockFinalityUpdate()
 	require.NoError(t, err)
 
 	GossipTypeMapping[reflect.TypeOf(msg)] = LightClientFinalityUpdateTopicFormat
@@ -699,6 +697,7 @@ func TestService_BroadcastDataColumn(t *testing.T) {
 		subnetsLock:           make(map[uint64]*sync.RWMutex),
 		subnetsLockLock:       sync.Mutex{},
 		peers:                 peers.NewStatus(t.Context(), &peers.StatusConfig{ScorerParams: &scorers.Config{}}),
+		custodyInfo:           &custodyInfo{},
 	}
 
 	// Create a listener.

beacon-chain/p2p/config.go

@@ -4,7 +4,6 @@ import (
 	"time"
 
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
 )
@@ -40,7 +39,6 @@ type Config struct {
 	StateNotifier        statefeed.Notifier
 	DB                   db.ReadOnlyDatabase
 	ClockWaiter          startup.ClockWaiter
-	CustodyInfo          *peerdas.CustodyInfo
 }
 
 // validateConfig validates whether the values provided are accurate and will set

beacon-chain/p2p/custody.go

@@ -3,11 +3,114 @@ package p2p
 import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
-var _ DataColumnsHandler = (*Service)(nil)
+var _ CustodyManager = (*Service)(nil)
+
+// EarliestAvailableSlot returns the earliest available slot.
+func (s *Service) EarliestAvailableSlot() (primitives.Slot, error) {
+	s.custodyInfoLock.RLock()
+	defer s.custodyInfoLock.RUnlock()
+
+	if s.custodyInfo == nil {
+		return 0, errors.New("no custody info available")
+	}
+
+	return s.custodyInfo.earliestAvailableSlot, nil
+}
+
+// CustodyGroupCount returns the custody group count.
+func (s *Service) CustodyGroupCount() (uint64, error) {
+	s.custodyInfoLock.Lock()
+	defer s.custodyInfoLock.Unlock()
+
+	if s.custodyInfo == nil {
+		return 0, errors.New("no custody info available")
+	}
+
+	return s.custodyInfo.groupCount, nil
+}
+
+// UpdateCustodyInfo updates the stored custody group count to the incoming one
+// if the incoming one is greater than the stored one. In this case, the
+// incoming earliest available slot should be greater than or equal to the
+// stored one or an error is returned.
+//
+//   - If there is no stored custody info, or
+//   - If the incoming earliest available slot is greater than or equal to the
+//     fulu fork slot and the incoming custody group count is greater than the
+//     number of samples per slot
+//
+// then the stored earliest available slot is updated to the incoming one.
+//
+// This function returns a boolean indicating whether the custody info was
+// updated and the (possibly updated) custody info itself.
+//
+// Rationale:
+//   - The custody group count can only be increased (specification)
+//   - If the custody group count is increased before Fulu, we can still serve
+//     all the data, since there is no sharding before Fulu. As a consequence
+//     we do not need to update the earliest available slot in this case.
+//   - If the custody group count is increased after Fulu, but to a value less
+//     than or equal to the number of samples per slot, we can still serve all
+//     the data, since we store all sampled data column sidecars in all cases.
+//     As a consequence, we do not need to update the earliest available slot
+//   - If the custody group count is increased after Fulu to a value higher than
+//     the number of samples per slot, then, until the backfill is complete, we
+//     are unable to serve the data column sidecars corresponding to the new
+//     custody groups. As a consequence, we need to update the earliest
+//     available slot to inform the peers that we are not able to serve data
+//     column sidecars before this point.
+func (s *Service) UpdateCustodyInfo(earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error) {
+	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
+
+	s.custodyInfoLock.Lock()
+	defer s.custodyInfoLock.Unlock()
+
+	if s.custodyInfo == nil {
+		s.custodyInfo = &custodyInfo{
+			earliestAvailableSlot: earliestAvailableSlot,
+			groupCount:            custodyGroupCount,
+		}
+		return earliestAvailableSlot, custodyGroupCount, nil
+	}
+
+	inMemory := s.custodyInfo
+	if custodyGroupCount <= inMemory.groupCount {
+		return inMemory.earliestAvailableSlot, inMemory.groupCount, nil
+	}
+
+	if earliestAvailableSlot < inMemory.earliestAvailableSlot {
+		return 0, 0, errors.Errorf(
+			"earliest available slot %d is less than the current one %d. (custody group count: %d, current one: %d)",
+			earliestAvailableSlot, inMemory.earliestAvailableSlot, custodyGroupCount, inMemory.groupCount,
+		)
+	}
+
+	if custodyGroupCount <= samplesPerSlot {
+		inMemory.groupCount = custodyGroupCount
+		return inMemory.earliestAvailableSlot, custodyGroupCount, nil
+	}
+
+	fuluForkSlot, err := fuluForkSlot()
+	if err != nil {
+		return 0, 0, errors.Wrap(err, "fulu fork slot")
+	}
+
+	if earliestAvailableSlot < fuluForkSlot {
+		inMemory.groupCount = custodyGroupCount
+		return inMemory.earliestAvailableSlot, custodyGroupCount, nil
+	}
+
+	inMemory.earliestAvailableSlot = earliestAvailableSlot
+	inMemory.groupCount = custodyGroupCount
+	return earliestAvailableSlot, custodyGroupCount, nil
+}
 
 // CustodyGroupCountFromPeer retrieves custody group count from a peer.
 // It first tries to get the custody group count from the peer's metadata,
@@ -72,3 +175,19 @@ func (s *Service) custodyGroupCountFromPeerENR(pid peer.ID) uint64 {
 
 	return custodyGroupCount
 }
+
+func fuluForkSlot() (primitives.Slot, error) {
+	beaconConfig := params.BeaconConfig()
+
+	fuluForkEpoch := beaconConfig.FuluForkEpoch
+	if fuluForkEpoch == beaconConfig.FarFutureEpoch {
+		return beaconConfig.FarFutureSlot, nil
+	}
+
+	forkFuluSlot, err := slots.EpochStart(fuluForkEpoch)
+	if err != nil {
+		return 0, errors.Wrap(err, "epoch start")
+	}
+
+	return forkFuluSlot, nil
+}

beacon-chain/p2p/custody_test.go

@@ -1,12 +1,15 @@
 package p2p
 
 import (
+	"context"
+	"strings"
 	"testing"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/scorers"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/wrapper"
 	pb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1/metadata"
@@ -15,6 +18,174 @@ import (
 	"github.com/libp2p/go-libp2p/core/network"
 )
 
+func TestEarliestAvailableSlot(t *testing.T) {
+	t.Run("No custody info available", func(t *testing.T) {
+		service := &Service{
+			custodyInfo: nil,
+		}
+
+		_, err := service.EarliestAvailableSlot()
+
+		require.NotNil(t, err)
+	})
+
+	t.Run("Valid custody info", func(t *testing.T) {
+		const expected primitives.Slot = 100
+
+		service := &Service{
+			custodyInfo: &custodyInfo{
+				earliestAvailableSlot: expected,
+			},
+		}
+
+		slot, err := service.EarliestAvailableSlot()
+
+		require.NoError(t, err)
+		require.Equal(t, expected, slot)
+	})
+}
+
+func TestCustodyGroupCount(t *testing.T) {
+	t.Run("No custody info available", func(t *testing.T) {
+		service := &Service{
+			custodyInfo: nil,
+		}
+
+		_, err := service.CustodyGroupCount()
+
+		require.NotNil(t, err)
+		require.Equal(t, true, strings.Contains(err.Error(), "no custody info available"))
+	})
+
+	t.Run("Valid custody info", func(t *testing.T) {
+		const expected uint64 = 5
+
+		service := &Service{
+			custodyInfo: &custodyInfo{
+				groupCount: expected,
+			},
+		}
+
+		count, err := service.CustodyGroupCount()
+
+		require.NoError(t, err)
+		require.Equal(t, expected, count)
+	})
+}
+
+func TestUpdateCustodyInfo(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	config := params.BeaconConfig()
+	config.SamplesPerSlot = 8
+	config.FuluForkEpoch = 10
+	params.OverrideBeaconConfig(config)
+
+	testCases := []struct {
+		name               string
+		initialCustodyInfo *custodyInfo
+		inputSlot          primitives.Slot
+		inputGroupCount    uint64
+		expectedUpdated    bool
+		expectedSlot       primitives.Slot
+		expectedGroupCount uint64
+		expectedErr        string
+	}{
+		{
+			name:               "First time setting custody info",
+			initialCustodyInfo: nil,
+			inputSlot:          100,
+			inputGroupCount:    5,
+			expectedUpdated:    true,
+			expectedSlot:       100,
+			expectedGroupCount: 5,
+		},
+		{
+			name: "Group count decrease - no update",
+			initialCustodyInfo: &custodyInfo{
+				earliestAvailableSlot: 50,
+				groupCount:            10,
+			},
+			inputSlot:          60,
+			inputGroupCount:    8,
+			expectedUpdated:    false,
+			expectedSlot:       50,
+			expectedGroupCount: 10,
+		},
+		{
+			name: "Earliest slot decrease - error",
+			initialCustodyInfo: &custodyInfo{
+				earliestAvailableSlot: 100,
+				groupCount:            5,
+			},
+			inputSlot:       50,
+			inputGroupCount: 10,
+			expectedErr:     "earliest available slot 50 is less than the current one 100",
+		},
+		{
+			name: "Group count increase but <= samples per slot",
+			initialCustodyInfo: &custodyInfo{
+				earliestAvailableSlot: 50,
+				groupCount:            5,
+			},
+			inputSlot:          60,
+			inputGroupCount:    8,
+			expectedUpdated:    true,
+			expectedSlot:       50,
+			expectedGroupCount: 8,
+		},
+		{
+			name: "Group count increase > samples per slot, before Fulu fork",
+			initialCustodyInfo: &custodyInfo{
+				earliestAvailableSlot: 50,
+				groupCount:            5,
+			},
+			inputSlot:          60,
+			inputGroupCount:    15,
+			expectedUpdated:    true,
+			expectedSlot:       50,
+			expectedGroupCount: 15,
+		},
+		{
+			name: "Group count increase > samples per slot, after Fulu fork",
+			initialCustodyInfo: &custodyInfo{
+				earliestAvailableSlot: 50,
+				groupCount:            5,
+			},
+			inputSlot:          500,
+			inputGroupCount:    15,
+			expectedUpdated:    true,
+			expectedSlot:       500,
+			expectedGroupCount: 15,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			service := &Service{
+				custodyInfo: tc.initialCustodyInfo,
+			}
+
+			slot, groupCount, err := service.UpdateCustodyInfo(tc.inputSlot, tc.inputGroupCount)
+
+			if tc.expectedErr != "" {
+				require.NotNil(t, err)
+				require.Equal(t, true, strings.Contains(err.Error(), tc.expectedErr))
+				return
+			}
+
+			require.NoError(t, err)
+			require.Equal(t, tc.expectedSlot, slot)
+			require.Equal(t, tc.expectedGroupCount, groupCount)
+
+			if tc.expectedUpdated {
+				require.NotNil(t, service.custodyInfo)
+				require.Equal(t, tc.expectedSlot, service.custodyInfo.earliestAvailableSlot)
+				require.Equal(t, tc.expectedGroupCount, service.custodyInfo.groupCount)
+			}
+		})
+	}
+}
+
 func TestCustodyGroupCountFromPeer(t *testing.T) {
 	const (
 		expectedENR      uint64 = 7
@@ -109,3 +280,59 @@ func TestCustodyGroupCountFromPeer(t *testing.T) {
 	}
 
 }
+
+func TestCustodyGroupCountFromPeerENR(t *testing.T) {
+	const (
+		expectedENR uint64 = 7
+		pid                = "test-id"
+	)
+
+	cgc := peerdas.Cgc(expectedENR)
+	custodyRequirement := params.BeaconConfig().CustodyRequirement
+
+	testCases := []struct {
+		name     string
+		record   *enr.Record
+		expected uint64
+		wantErr  bool
+	}{
+		{
+			name:     "No ENR record",
+			record:   nil,
+			expected: custodyRequirement,
+		},
+		{
+			name:     "Empty ENR record",
+			record:   &enr.Record{},
+			expected: custodyRequirement,
+		},
+		{
+			name: "Valid ENR with custody group count",
+			record: func() *enr.Record {
+				record := &enr.Record{}
+				record.Set(cgc)
+				return record
+			}(),
+			expected: expectedENR,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			peers := peers.NewStatus(context.Background(), &peers.StatusConfig{
+				ScorerParams: &scorers.Config{},
+			})
+
+			if tc.record != nil {
+				peers.Add(tc.record, pid, nil, network.DirOutbound)
+			}
+
+			service := &Service{
+				peers: peers,
+			}
+
+			actual := service.custodyGroupCountFromPeerENR(pid)
+			require.Equal(t, tc.expected, actual)
+		})
+	}
+}

beacon-chain/p2p/discovery.go

@@ -236,22 +236,40 @@ func (s *Service) RefreshPersistentSubnets() {
 	// Get the sync subnet bitfield in our metadata.
 	currentBitSInMetadata := s.Metadata().SyncnetsBitfield()
 
-	// Is our sync bitvector record up to date?
 	isBitSUpToDate := bytes.Equal(bitS, inRecordBitS) && bytes.Equal(bitS, currentBitSInMetadata)
 
 	// Compare current epoch with the Fulu fork epoch.
 	fuluForkEpoch := params.BeaconConfig().FuluForkEpoch
 
+	custodyGroupCount, inRecordCustodyGroupCount := uint64(0), uint64(0)
+	if params.FuluEnabled() {
+		// Get the custody group count we store in our record.
+		inRecordCustodyGroupCount, err = peerdas.CustodyGroupCountFromRecord(record)
+		if err != nil {
+			log.WithError(err).Error("Could not retrieve custody group count")
+			return
+		}
+
+		custodyGroupCount, err = s.CustodyGroupCount()
+		if err != nil {
+			log.WithError(err).Error("Could not retrieve custody group count")
+			return
+		}
+	}
+
 	// We add `1` to the current epoch because we want to prepare one epoch before the Fulu fork.
 	if currentEpoch+1 < fuluForkEpoch {
+		// Is our custody group count record up to date?
+		isCustodyGroupCountUpToDate := custodyGroupCount == inRecordCustodyGroupCount
+
 		// Altair behaviour.
-		if metadataVersion == version.Altair && isBitVUpToDate && isBitSUpToDate {
+		if metadataVersion == version.Altair && isBitVUpToDate && isBitSUpToDate && (!params.FuluEnabled() || isCustodyGroupCountUpToDate) {
 			// Nothing to do, return early.
 			return
 		}
 
 		// Some data have changed, update our record and metadata.
-		s.updateSubnetRecordWithMetadataV2(bitV, bitS)
+		s.updateSubnetRecordWithMetadataV2(bitV, bitS, custodyGroupCount)
 
 		// Ping all peers to inform them of new metadata
 		s.pingPeersAndLogEnr()
@@ -259,16 +277,6 @@ func (s *Service) RefreshPersistentSubnets() {
 		return
 	}
 
-	// Get the current custody group count.
-	custodyGroupCount := s.cfg.CustodyInfo.ActualGroupCount()
-
-	// Get the custody group count we store in our record.
-	inRecordCustodyGroupCount, err := peerdas.CustodyGroupCountFromRecord(record)
-	if err != nil {
-		log.WithError(err).Error("Could not retrieve custody subnet count")
-		return
-	}
-
 	// Get the custody group count in our metadata.
 	inMetadataCustodyGroupCount := s.Metadata().CustodyGroupCount()
 
@@ -565,11 +573,6 @@ func (s *Service) createLocalNode(
 		localNode.Set(quicEntry)
 	}
 
-	if params.FuluEnabled() {
-		custodyGroupCount := s.cfg.CustodyInfo.ActualGroupCount()
-		localNode.Set(peerdas.Cgc(custodyGroupCount))
-	}
-
 	localNode.SetFallbackIP(ipAddr)
 	localNode.SetFallbackUDP(udpPort)
 
@@ -581,6 +584,16 @@ func (s *Service) createLocalNode(
 	localNode = initializeAttSubnets(localNode)
 	localNode = initializeSyncCommSubnets(localNode)
 
+	if params.FuluEnabled() {
+		custodyGroupCount, err := s.CustodyGroupCount()
+		if err != nil {
+			return nil, errors.Wrap(err, "could not retrieve custody group count")
+		}
+
+		custodyGroupCountEntry := peerdas.Cgc(custodyGroupCount)
+		localNode.Set(custodyGroupCountEntry)
+	}
+
 	if s.cfg != nil && s.cfg.HostAddress != "" {
 		hostIP := net.ParseIP(s.cfg.HostAddress)
 		if hostIP.To4() == nil && hostIP.To16() == nil {

beacon-chain/p2p/discovery_test.go

@@ -16,7 +16,6 @@ import (
 
 	mock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/peerdata"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/scorers"
@@ -65,6 +64,7 @@ func TestCreateListener(t *testing.T) {
 		genesisTime:           time.Now(),
 		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
 		cfg:                   &Config{UDPPort: uint(port)},
+		custodyInfo:           &custodyInfo{},
 	}
 	listener, err := s.createListener(ipAddr, pkey)
 	require.NoError(t, err)
@@ -91,6 +91,7 @@ func TestStartDiscV5_DiscoverAllPeers(t *testing.T) {
 		cfg:                   &Config{UDPPort: uint(port), PingInterval: testPingInterval, DisableLivenessCheck: true},
 		genesisTime:           genesisTime,
 		genesisValidatorsRoot: genesisValidatorsRoot,
+		custodyInfo:           &custodyInfo{},
 	}
 	bootListener, err := s.createListener(ipAddr, pkey)
 	require.NoError(t, err)
@@ -116,6 +117,7 @@ func TestStartDiscV5_DiscoverAllPeers(t *testing.T) {
 			cfg:                   cfg,
 			genesisTime:           genesisTime,
 			genesisValidatorsRoot: genesisValidatorsRoot,
+			custodyInfo:           &custodyInfo{},
 		}
 		listener, err := s.startDiscoveryV5(ipAddr, pkey)
 		assert.NoError(t, err, "Could not start discovery for node")
@@ -157,27 +159,27 @@ func TestCreateLocalNode(t *testing.T) {
 	}{
 		{
 			name:          "valid config",
-			cfg:           &Config{CustodyInfo: &peerdas.CustodyInfo{}},
+			cfg:           &Config{},
 			expectedError: false,
 		},
 		{
 			name:          "invalid host address",
-			cfg:           &Config{HostAddress: "invalid", CustodyInfo: &peerdas.CustodyInfo{}},
+			cfg:           &Config{HostAddress: "invalid"},
 			expectedError: true,
 		},
 		{
 			name:          "valid host address",
-			cfg:           &Config{HostAddress: "192.168.0.1", CustodyInfo: &peerdas.CustodyInfo{}},
+			cfg:           &Config{HostAddress: "192.168.0.1"},
 			expectedError: false,
 		},
 		{
 			name:          "invalid host DNS",
-			cfg:           &Config{HostDNS: "invalid", CustodyInfo: &peerdas.CustodyInfo{}},
+			cfg:           &Config{HostDNS: "invalid"},
 			expectedError: true,
 		},
 		{
 			name:          "valid host DNS",
-			cfg:           &Config{HostDNS: "www.google.com", CustodyInfo: &peerdas.CustodyInfo{}},
+			cfg:           &Config{HostDNS: "www.google.com"},
 			expectedError: false,
 		},
 	}
@@ -191,6 +193,8 @@ func TestCreateLocalNode(t *testing.T) {
 				quicPort = 3000
 			)
 
+			custodyRequirement := params.BeaconConfig().CustodyRequirement
+
 			// Create a private key.
 			address, privKey := createAddrAndPrivKey(t)
 
@@ -199,6 +203,7 @@ func TestCreateLocalNode(t *testing.T) {
 				genesisTime:           time.Now(),
 				genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
 				cfg:                   tt.cfg,
+				custodyInfo:           &custodyInfo{groupCount: custodyRequirement},
 			}
 
 			localNode, err := service.createLocalNode(privKey, address, udpPort, tcpPort, quicPort)
@@ -210,7 +215,7 @@ func TestCreateLocalNode(t *testing.T) {
 			require.NoError(t, err)
 
 			expectedAddress := address
-			if tt.cfg.HostAddress != "" {
+			if tt.cfg != nil && tt.cfg.HostAddress != "" {
 				expectedAddress = net.ParseIP(tt.cfg.HostAddress)
 			}
 
@@ -250,8 +255,8 @@ func TestCreateLocalNode(t *testing.T) {
 
 			// Check cgc config.
 			custodyGroupCount := new(uint64)
-			require.NoError(t, localNode.Node().Record().Load(enr.WithEntry(peerdas.CustodyGroupCountEnrKey, custodyGroupCount)))
-			require.Equal(t, params.BeaconConfig().CustodyRequirement, *custodyGroupCount)
+			require.NoError(t, localNode.Node().Record().Load(enr.WithEntry(params.BeaconNetworkConfig().CustodyGroupCountKey, custodyGroupCount)))
+			require.Equal(t, custodyRequirement, *custodyGroupCount)
 		})
 	}
 }
@@ -263,6 +268,7 @@ func TestRebootDiscoveryListener(t *testing.T) {
 		genesisTime:           time.Now(),
 		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
 		cfg:                   &Config{UDPPort: uint(port)},
+		custodyInfo:           &custodyInfo{},
 	}
 
 	createListener := func() (*discover.UDPv5, error) {
@@ -295,6 +301,7 @@ func TestMultiAddrsConversion_InvalidIPAddr(t *testing.T) {
 		genesisTime:           time.Now(),
 		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
 		cfg:                   &Config{},
+		custodyInfo:           &custodyInfo{},
 	}
 	node, err := s.createLocalNode(pkey, addr, 0, 0, 0)
 	require.NoError(t, err)
@@ -313,6 +320,7 @@ func TestMultiAddrConversion_OK(t *testing.T) {
 		},
 		genesisTime:           time.Now(),
 		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+		custodyInfo:           &custodyInfo{},
 	}
 	listener, err := s.createListener(ipAddr, pkey)
 	require.NoError(t, err)
@@ -386,6 +394,7 @@ func TestHostIsResolved(t *testing.T) {
 		},
 		genesisTime:           time.Now(),
 		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+		custodyInfo:           &custodyInfo{},
 	}
 	ip, key := createAddrAndPrivKey(t)
 	list, err := s.createListener(ip, key)
@@ -455,6 +464,7 @@ func TestUDPMultiAddress(t *testing.T) {
 		cfg:                   &Config{UDPPort: uint(port)},
 		genesisTime:           genesisTime,
 		genesisValidatorsRoot: genesisValidatorsRoot,
+		custodyInfo:           &custodyInfo{},
 	}
 
 	createListener := func() (*discover.UDPv5, error) {
@@ -655,7 +665,7 @@ func checkPingCountCacheMetadataRecord(
 	if expected.custodyGroupCount != nil {
 		// Check custody subnet count in ENR.
 		var actualCustodyGroupCount uint64
-		err := service.dv5Listener.LocalNode().Node().Record().Load(enr.WithEntry(peerdas.CustodyGroupCountEnrKey, &actualCustodyGroupCount))
+		err := service.dv5Listener.LocalNode().Node().Record().Load(enr.WithEntry(params.BeaconNetworkConfig().CustodyGroupCountKey, &actualCustodyGroupCount))
 		require.NoError(t, err)
 		require.Equal(t, *expected.custodyGroupCount, actualCustodyGroupCount)
 
@@ -818,10 +828,11 @@ func TestRefreshPersistentSubnets(t *testing.T) {
 					actualPingCount++
 					return nil
 				},
-				cfg:                   &Config{UDPPort: 2000, CustodyInfo: &peerdas.CustodyInfo{}},
+				cfg:                   &Config{UDPPort: 2000},
 				peers:                 p2p.Peers(),
 				genesisTime:           time.Now().Add(-time.Duration(tc.epochSinceGenesis*secondsPerEpoch) * time.Second),
 				genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+				custodyInfo:           &custodyInfo{groupCount: custodyGroupCount},
 			}
 
 			// Set the listener and the metadata.

beacon-chain/p2p/fork_test.go

@@ -40,6 +40,7 @@ func TestStartDiscv5_DifferentForkDigests(t *testing.T) {
 		},
 		genesisTime:           genesisTime,
 		genesisValidatorsRoot: genesisValidatorsRoot,
+		custodyInfo:           &custodyInfo{},
 	}
 	bootListener, err := s.createListener(ipAddr, pkey)
 	require.NoError(t, err)
@@ -73,6 +74,7 @@ func TestStartDiscv5_DifferentForkDigests(t *testing.T) {
 			cfg:                   cfg,
 			genesisTime:           genesisTime,
 			genesisValidatorsRoot: root,
+			custodyInfo:           &custodyInfo{},
 		}
 		listener, err := s.startDiscoveryV5(ipAddr, pkey)
 		assert.NoError(t, err, "Could not start discovery for node")
@@ -134,6 +136,7 @@ func TestStartDiscv5_SameForkDigests_DifferentNextForkData(t *testing.T) {
 		cfg:                   &Config{UDPPort: uint(port), PingInterval: testPingInterval, DisableLivenessCheck: true},
 		genesisTime:           genesisTime,
 		genesisValidatorsRoot: genesisValidatorsRoot,
+		custodyInfo:           &custodyInfo{},
 	}
 	bootListener, err := s.createListener(ipAddr, pkey)
 	require.NoError(t, err)
@@ -168,6 +171,7 @@ func TestStartDiscv5_SameForkDigests_DifferentNextForkData(t *testing.T) {
 			cfg:                   cfg,
 			genesisTime:           genesisTime,
 			genesisValidatorsRoot: genesisValidatorsRoot,
+			custodyInfo:           &custodyInfo{},
 		}
 		listener, err := s.startDiscoveryV5(ipAddr, pkey)
 		assert.NoError(t, err, "Could not start discovery for node")

beacon-chain/p2p/interfaces.go

@@ -7,6 +7,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1/metadata"
 	"github.com/ethereum/go-ethereum/p2p/enode"
@@ -32,13 +33,14 @@ type (
 		ConnectionHandler
 		PeersProvider
 		MetadataProvider
-		DataColumnsHandler
+		CustodyManager
 	}
 
-	// Accessor provides access to the Broadcaster and PeerManager interfaces.
+	// Accessor provides access to the Broadcaster, PeerManager and CustodyManager interfaces.
 	Accessor interface {
 		Broadcaster
 		PeerManager
+		CustodyManager
 	}
 
 	// Broadcaster broadcasts messages to peers over the p2p pubsub protocol.
@@ -118,8 +120,11 @@ type (
 		MetadataSeq() uint64
 	}
 
-	// DataColumnsHandler abstracts some data columns related methods.
-	DataColumnsHandler interface {
+	// CustodyManager abstracts some data columns related methods.
+	CustodyManager interface {
+		EarliestAvailableSlot() (primitives.Slot, error)
+		CustodyGroupCount() (uint64, error)
+		UpdateCustodyInfo(earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error)
 		CustodyGroupCountFromPeer(peer.ID) uint64
 	}
 )

beacon-chain/p2p/peers/peerdata/store.go

@@ -54,7 +54,7 @@ type PeerData struct {
 	NextValidTime time.Time
 	// Chain related data.
 	MetaData                  metadata.Metadata
-	ChainState                *ethpb.Status
+	ChainState                *ethpb.StatusV2
 	ChainStateLastUpdated     time.Time
 	ChainStateValidationError error
 	// Scorers internal data.

beacon-chain/p2p/peers/scorers/peer_status.go

@@ -112,7 +112,7 @@ func (s *PeerStatusScorer) BadPeers() []peer.ID {
 }
 
 // SetPeerStatus sets chain state data for a given peer.
-func (s *PeerStatusScorer) SetPeerStatus(pid peer.ID, chainState *pb.Status, validationError error) {
+func (s *PeerStatusScorer) SetPeerStatus(pid peer.ID, chainState *pb.StatusV2, validationError error) {
 	s.store.Lock()
 	defer s.store.Unlock()
 
@@ -130,14 +130,14 @@ func (s *PeerStatusScorer) SetPeerStatus(pid peer.ID, chainState *pb.Status, val
 // PeerStatus gets the chain state of the given remote peer.
 // This can return nil if there is no known chain state for the peer.
 // This will error if the peer does not exist.
-func (s *PeerStatusScorer) PeerStatus(pid peer.ID) (*pb.Status, error) {
+func (s *PeerStatusScorer) PeerStatus(pid peer.ID) (*pb.StatusV2, error) {
 	s.store.RLock()
 	defer s.store.RUnlock()
 	return s.peerStatusNoLock(pid)
 }
 
 // peerStatusNoLock lock-free version of PeerStatus.
-func (s *PeerStatusScorer) peerStatusNoLock(pid peer.ID) (*pb.Status, error) {
+func (s *PeerStatusScorer) peerStatusNoLock(pid peer.ID) (*pb.StatusV2, error) {
 	if peerData, ok := s.store.PeerData(pid); ok {
 		if peerData.ChainState == nil {
 			return nil, peerdata.ErrNoPeerStatus

beacon-chain/p2p/peers/scorers/peer_status_test.go

@@ -35,7 +35,7 @@ func TestScorers_PeerStatus_Score(t *testing.T) {
 			name: "existent bad peer",
 			update: func(scorer *scorers.PeerStatusScorer) {
 				scorer.SetHeadSlot(0)
-				scorer.SetPeerStatus("peer1", &pb.Status{
+				scorer.SetPeerStatus("peer1", &pb.StatusV2{
 					HeadRoot: make([]byte, 32),
 					HeadSlot: 64,
 				}, p2ptypes.ErrWrongForkDigestVersion)
@@ -48,7 +48,7 @@ func TestScorers_PeerStatus_Score(t *testing.T) {
 			name: "existent peer no head slot for the host node is known",
 			update: func(scorer *scorers.PeerStatusScorer) {
 				scorer.SetHeadSlot(0)
-				scorer.SetPeerStatus("peer1", &pb.Status{
+				scorer.SetPeerStatus("peer1", &pb.StatusV2{
 					HeadRoot: make([]byte, 32),
 					HeadSlot: 64,
 				}, nil)
@@ -61,7 +61,7 @@ func TestScorers_PeerStatus_Score(t *testing.T) {
 			name: "existent peer head is before ours",
 			update: func(scorer *scorers.PeerStatusScorer) {
 				scorer.SetHeadSlot(128)
-				scorer.SetPeerStatus("peer1", &pb.Status{
+				scorer.SetPeerStatus("peer1", &pb.StatusV2{
 					HeadRoot: make([]byte, 32),
 					HeadSlot: 64,
 				}, nil)
@@ -75,12 +75,12 @@ func TestScorers_PeerStatus_Score(t *testing.T) {
 			update: func(scorer *scorers.PeerStatusScorer) {
 				headSlot := primitives.Slot(128)
 				scorer.SetHeadSlot(headSlot)
-				scorer.SetPeerStatus("peer1", &pb.Status{
+				scorer.SetPeerStatus("peer1", &pb.StatusV2{
 					HeadRoot: make([]byte, 32),
 					HeadSlot: headSlot + 64,
 				}, nil)
 				// Set another peer to a higher score.
-				scorer.SetPeerStatus("peer2", &pb.Status{
+				scorer.SetPeerStatus("peer2", &pb.StatusV2{
 					HeadRoot: make([]byte, 32),
 					HeadSlot: headSlot + 128,
 				}, nil)
@@ -95,7 +95,7 @@ func TestScorers_PeerStatus_Score(t *testing.T) {
 			update: func(scorer *scorers.PeerStatusScorer) {
 				headSlot := primitives.Slot(128)
 				scorer.SetHeadSlot(headSlot)
-				scorer.SetPeerStatus("peer1", &pb.Status{
+				scorer.SetPeerStatus("peer1", &pb.StatusV2{
 					HeadRoot: make([]byte, 32),
 					HeadSlot: headSlot + 64,
 				}, nil)
@@ -108,7 +108,7 @@ func TestScorers_PeerStatus_Score(t *testing.T) {
 			name: "existent peer no max known slot",
 			update: func(scorer *scorers.PeerStatusScorer) {
 				scorer.SetHeadSlot(0)
-				scorer.SetPeerStatus("peer1", &pb.Status{
+				scorer.SetPeerStatus("peer1", &pb.StatusV2{
 					HeadRoot: make([]byte, 32),
 					HeadSlot: 0,
 				}, nil)
@@ -141,7 +141,7 @@ func TestScorers_PeerStatus_IsBadPeer(t *testing.T) {
 	assert.NoError(t, peerStatuses.Scorers().IsBadPeer(pid))
 	assert.NoError(t, peerStatuses.Scorers().PeerStatusScorer().IsBadPeer(pid))
 
-	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid, &pb.Status{}, p2ptypes.ErrWrongForkDigestVersion)
+	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid, &pb.StatusV2{}, p2ptypes.ErrWrongForkDigestVersion)
 	assert.NotNil(t, peerStatuses.Scorers().IsBadPeer(pid))
 	assert.NotNil(t, peerStatuses.Scorers().PeerStatusScorer().IsBadPeer(pid))
 }
@@ -160,9 +160,9 @@ func TestScorers_PeerStatus_BadPeers(t *testing.T) {
 	assert.NoError(t, peerStatuses.Scorers().IsBadPeer(pid3))
 	assert.NoError(t, peerStatuses.Scorers().PeerStatusScorer().IsBadPeer(pid3))
 
-	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid1, &pb.Status{}, p2ptypes.ErrWrongForkDigestVersion)
-	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid2, &pb.Status{}, nil)
-	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid3, &pb.Status{}, p2ptypes.ErrWrongForkDigestVersion)
+	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid1, &pb.StatusV2{}, p2ptypes.ErrWrongForkDigestVersion)
+	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid2, &pb.StatusV2{}, nil)
+	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus(pid3, &pb.StatusV2{}, p2ptypes.ErrWrongForkDigestVersion)
 	assert.NotNil(t, peerStatuses.Scorers().IsBadPeer(pid1))
 	assert.NotNil(t, peerStatuses.Scorers().PeerStatusScorer().IsBadPeer(pid1))
 	assert.NoError(t, peerStatuses.Scorers().IsBadPeer(pid2))
@@ -179,12 +179,12 @@ func TestScorers_PeerStatus_PeerStatus(t *testing.T) {
 	})
 	status, err := peerStatuses.Scorers().PeerStatusScorer().PeerStatus("peer1")
 	require.ErrorContains(t, peerdata.ErrPeerUnknown.Error(), err)
-	assert.Equal(t, (*pb.Status)(nil), status)
+	assert.Equal(t, (*pb.StatusV2)(nil), status)
 
-	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus("peer1", &pb.Status{
+	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus("peer1", &pb.StatusV2{
 		HeadSlot: 128,
 	}, nil)
-	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus("peer2", &pb.Status{
+	peerStatuses.Scorers().PeerStatusScorer().SetPeerStatus("peer2", &pb.StatusV2{
 		HeadSlot: 128,
 	}, p2ptypes.ErrInvalidEpoch)
 	status, err = peerStatuses.Scorers().PeerStatusScorer().PeerStatus("peer1")

beacon-chain/p2p/peers/status.go

@@ -205,14 +205,14 @@ func (p *Status) ENR(pid peer.ID) (*enr.Record, error) {
 }
 
 // SetChainState sets the chain state of the given remote peer.
-func (p *Status) SetChainState(pid peer.ID, chainState *pb.Status) {
+func (p *Status) SetChainState(pid peer.ID, chainState *pb.StatusV2) {
 	p.scorers.PeerStatusScorer().SetPeerStatus(pid, chainState, nil)
 }
 
 // ChainState gets the chain state of the given remote peer.
 // This will error if the peer does not exist.
 // This will error if there is no known chain state for the peer.
-func (p *Status) ChainState(pid peer.ID) (*pb.Status, error) {
+func (p *Status) ChainState(pid peer.ID) (*pb.StatusV2, error) {
 	return p.scorers.PeerStatusScorer().PeerStatus(pid)
 }
 

beacon-chain/p2p/peers/status_test.go

@@ -289,7 +289,7 @@ func TestPeerChainState(t *testing.T) {
 	require.NoError(t, err)
 
 	finalizedEpoch := primitives.Epoch(123)
-	p.SetChainState(id, &pb.Status{FinalizedEpoch: finalizedEpoch})
+	p.SetChainState(id, &pb.StatusV2{FinalizedEpoch: finalizedEpoch})
 
 	resChainState, err := p.ChainState(id)
 	require.NoError(t, err)
@@ -324,7 +324,7 @@ func TestPeerWithNilChainState(t *testing.T) {
 
 	resChainState, err := p.ChainState(id)
 	require.Equal(t, peerdata.ErrNoPeerStatus, err)
-	var nothing *pb.Status
+	var nothing *pb.StatusV2
 	require.Equal(t, resChainState, nothing)
 }
 
@@ -616,7 +616,7 @@ func TestTrimmedOrderedPeers(t *testing.T) {
 
 	// Peer 1
 	pid1 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid1, &pb.Status{
+	p.SetChainState(pid1, &pb.StatusV2{
 		HeadSlot:       3 * params.BeaconConfig().SlotsPerEpoch,
 		FinalizedEpoch: 3,
 		FinalizedRoot:  mockroot3[:],
@@ -624,7 +624,7 @@ func TestTrimmedOrderedPeers(t *testing.T) {
 
 	// Peer 2
 	pid2 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid2, &pb.Status{
+	p.SetChainState(pid2, &pb.StatusV2{
 		HeadSlot:       4 * params.BeaconConfig().SlotsPerEpoch,
 		FinalizedEpoch: 4,
 		FinalizedRoot:  mockroot4[:],
@@ -632,7 +632,7 @@ func TestTrimmedOrderedPeers(t *testing.T) {
 
 	// Peer 3
 	pid3 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid3, &pb.Status{
+	p.SetChainState(pid3, &pb.StatusV2{
 		HeadSlot:       5 * params.BeaconConfig().SlotsPerEpoch,
 		FinalizedEpoch: 5,
 		FinalizedRoot:  mockroot5[:],
@@ -640,7 +640,7 @@ func TestTrimmedOrderedPeers(t *testing.T) {
 
 	// Peer 4
 	pid4 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid4, &pb.Status{
+	p.SetChainState(pid4, &pb.StatusV2{
 		HeadSlot:       2 * params.BeaconConfig().SlotsPerEpoch,
 		FinalizedEpoch: 2,
 		FinalizedRoot:  mockroot2[:],
@@ -648,7 +648,7 @@ func TestTrimmedOrderedPeers(t *testing.T) {
 
 	// Peer 5
 	pid5 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid5, &pb.Status{
+	p.SetChainState(pid5, &pb.StatusV2{
 		HeadSlot:       2 * params.BeaconConfig().SlotsPerEpoch,
 		FinalizedEpoch: 2,
 		FinalizedRoot:  mockroot2[:],
@@ -1012,7 +1012,7 @@ func TestStatus_BestPeer(t *testing.T) {
 				},
 			})
 			for _, peerConfig := range tt.peers {
-				p.SetChainState(addPeer(t, p, peers.Connected), &pb.Status{
+				p.SetChainState(addPeer(t, p, peers.Connected), &pb.StatusV2{
 					FinalizedEpoch: peerConfig.finalizedEpoch,
 					HeadSlot:       peerConfig.headSlot,
 				})
@@ -1039,7 +1039,7 @@ func TestBestFinalized_returnsMaxValue(t *testing.T) {
 	for i := 0; i <= maxPeers+100; i++ {
 		p.Add(new(enr.Record), peer.ID(rune(i)), nil, network.DirOutbound)
 		p.SetConnectionState(peer.ID(rune(i)), peers.Connected)
-		p.SetChainState(peer.ID(rune(i)), &pb.Status{
+		p.SetChainState(peer.ID(rune(i)), &pb.StatusV2{
 			FinalizedEpoch: 10,
 		})
 	}
@@ -1062,7 +1062,7 @@ func TestStatus_BestNonFinalized(t *testing.T) {
 	for i, headSlot := range peerSlots {
 		p.Add(new(enr.Record), peer.ID(rune(i)), nil, network.DirOutbound)
 		p.SetConnectionState(peer.ID(rune(i)), peers.Connected)
-		p.SetChainState(peer.ID(rune(i)), &pb.Status{
+		p.SetChainState(peer.ID(rune(i)), &pb.StatusV2{
 			HeadSlot: headSlot,
 		})
 	}
@@ -1085,17 +1085,17 @@ func TestStatus_CurrentEpoch(t *testing.T) {
 	})
 	// Peer 1
 	pid1 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid1, &pb.Status{
+	p.SetChainState(pid1, &pb.StatusV2{
 		HeadSlot: params.BeaconConfig().SlotsPerEpoch * 4,
 	})
 	// Peer 2
 	pid2 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid2, &pb.Status{
+	p.SetChainState(pid2, &pb.StatusV2{
 		HeadSlot: params.BeaconConfig().SlotsPerEpoch * 5,
 	})
 	// Peer 3
 	pid3 := addPeer(t, p, peers.Connected)
-	p.SetChainState(pid3, &pb.Status{
+	p.SetChainState(pid3, &pb.StatusV2{
 		HeadSlot: params.BeaconConfig().SlotsPerEpoch * 4,
 	})
 

beacon-chain/p2p/rpc_topic_mappings.go

@@ -108,6 +108,8 @@ const (
 	RPCDataColumnSidecarsByRangeTopicV1 = protocolPrefix + DataColumnSidecarsByRangeName + SchemaVersionV1
 
 	// V2 RPC Topics
+	// RPCStatusTopicV2 defines the v1 topic for the status rpc method.
+	RPCStatusTopicV2 = protocolPrefix + StatusMessageName + SchemaVersionV2
 	// 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.
@@ -130,6 +132,7 @@ var (
 	RPCTopicMappings = map[string]interface{}{
 		// RPC Status Message
 		RPCStatusTopicV1: new(pb.Status),
+		RPCStatusTopicV2: new(pb.StatusV2),
 
 		// RPC Goodbye Message
 		RPCGoodByeTopicV1: new(primitives.SSZUint64),
@@ -201,6 +204,7 @@ var (
 
 	// Maps all the RPC messages which are to updated in fulu.
 	fuluMapping = map[string]string{
+		StatusMessageName:   SchemaVersionV2,
 		MetadataMessageName: SchemaVersionV3,
 	}
 

beacon-chain/p2p/rpc_topic_mappings_test.go

@@ -141,6 +141,11 @@ func TestTopicFromMessage_CorrectType(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, "/eth2/beacon_chain/req/beacon_blocks_by_range/2", topic)
 
+		// Modified in fulu fork.
+		topic, err = TopicFromMessage(StatusMessageName, fuluForkEpoch)
+		require.NoError(t, err)
+		require.Equal(t, "/eth2/beacon_chain/req/status/2", topic)
+
 		// Modified both in altair and fulu fork.
 		topic, err = TopicFromMessage(MetadataMessageName, fuluForkEpoch)
 		require.NoError(t, err)

beacon-chain/p2p/service.go

@@ -16,6 +16,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
 	"github.com/OffchainLabs/prysm/v6/config/features"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	leakybucket "github.com/OffchainLabs/prysm/v6/container/leaky-bucket"
 	"github.com/OffchainLabs/prysm/v6/monitoring/tracing/trace"
 	prysmnetwork "github.com/OffchainLabs/prysm/v6/network"
@@ -62,33 +63,42 @@ var (
 )
 
 // Service for managing peer to peer (p2p) networking.
-type Service struct {
-	started               bool
-	isPreGenesis          bool
-	pingMethod            func(ctx context.Context, id peer.ID) error
-	pingMethodLock        sync.RWMutex
-	cancel                context.CancelFunc
-	cfg                   *Config
-	peers                 *peers.Status
-	addrFilter            *multiaddr.Filters
-	ipLimiter             *leakybucket.Collector
-	privKey               *ecdsa.PrivateKey
-	metaData              metadata.Metadata
-	pubsub                *pubsub.PubSub
-	joinedTopics          map[string]*pubsub.Topic
-	joinedTopicsLock      sync.RWMutex
-	subnetsLock           map[uint64]*sync.RWMutex
-	subnetsLockLock       sync.Mutex // Lock access to subnetsLock
-	initializationLock    sync.Mutex
-	dv5Listener           ListenerRebooter
-	startupErr            error
-	ctx                   context.Context
-	host                  host.Host
-	genesisTime           time.Time
-	genesisValidatorsRoot []byte
-	activeValidatorCount  uint64
-	peerDisconnectionTime *cache.Cache
-}
+type (
+	Service struct {
+		started               bool
+		isPreGenesis          bool
+		pingMethod            func(ctx context.Context, id peer.ID) error
+		pingMethodLock        sync.RWMutex
+		cancel                context.CancelFunc
+		cfg                   *Config
+		peers                 *peers.Status
+		addrFilter            *multiaddr.Filters
+		ipLimiter             *leakybucket.Collector
+		privKey               *ecdsa.PrivateKey
+		metaData              metadata.Metadata
+		pubsub                *pubsub.PubSub
+		joinedTopics          map[string]*pubsub.Topic
+		joinedTopicsLock      sync.RWMutex
+		subnetsLock           map[uint64]*sync.RWMutex
+		subnetsLockLock       sync.Mutex // Lock access to subnetsLock
+		initializationLock    sync.Mutex
+		dv5Listener           ListenerRebooter
+		startupErr            error
+		ctx                   context.Context
+		host                  host.Host
+		genesisTime           time.Time
+		genesisValidatorsRoot []byte
+		activeValidatorCount  uint64
+		peerDisconnectionTime *cache.Cache
+		custodyInfo           *custodyInfo
+		custodyInfoLock       sync.RWMutex // Lock access to custodyInfo
+	}
+
+	custodyInfo struct {
+		earliestAvailableSlot primitives.Slot
+		groupCount            uint64
+	}
+)
 
 // NewService initializes a new p2p service compatible with shared.Service interface. No
 // connections are made until the Start function is called during the service registry startup.

beacon-chain/p2p/service_test.go

@@ -114,6 +114,7 @@ func TestService_Start_OnlyStartsOnce(t *testing.T) {
 	s, err := NewService(t.Context(), cfg)
 	require.NoError(t, err)
 	s.dv5Listener = &mockListener{}
+	s.custodyInfo = &custodyInfo{}
 	exitRoutine := make(chan bool)
 	go func() {
 		s.Start()
@@ -211,6 +212,7 @@ func TestListenForNewNodes(t *testing.T) {
 		cfg:                   cfg,
 		genesisTime:           genesisTime,
 		genesisValidatorsRoot: gvr[:],
+		custodyInfo:           &custodyInfo{},
 	}
 
 	bootListener, err := s.createListener(ipAddr, pkey)
@@ -252,6 +254,7 @@ func TestListenForNewNodes(t *testing.T) {
 			cfg:                   cfg,
 			genesisTime:           genesisTime,
 			genesisValidatorsRoot: gvr[:],
+			custodyInfo:           &custodyInfo{},
 		}
 
 		listener, err := s.startDiscoveryV5(ipAddr, pkey)
@@ -281,6 +284,7 @@ func TestListenForNewNodes(t *testing.T) {
 
 	s, err = NewService(t.Context(), cfg)
 	require.NoError(t, err)
+	s.custodyInfo = &custodyInfo{}
 
 	go s.Start()
 

beacon-chain/p2p/subnets.go

@@ -390,11 +390,23 @@ func (s *Service) updateSubnetRecordWithMetadata(bitV bitfield.Bitvector64) {
 // with a new value for a bitfield of subnets tracked. It also record's
 // the sync committee subnet in the enr. It also updates the node's
 // metadata by increasing the sequence number and the subnets tracked by the node.
-func (s *Service) updateSubnetRecordWithMetadataV2(bitVAtt bitfield.Bitvector64, bitVSync bitfield.Bitvector4) {
+func (s *Service) updateSubnetRecordWithMetadataV2(
+	bitVAtt bitfield.Bitvector64,
+	bitVSync bitfield.Bitvector4,
+	custodyGroupCount uint64,
+) {
 	entry := enr.WithEntry(attSubnetEnrKey, &bitVAtt)
 	subEntry := enr.WithEntry(syncCommsSubnetEnrKey, &bitVSync)
-	s.dv5Listener.LocalNode().Set(entry)
-	s.dv5Listener.LocalNode().Set(subEntry)
+
+	localNode := s.dv5Listener.LocalNode()
+	localNode.Set(entry)
+	localNode.Set(subEntry)
+
+	if params.FuluEnabled() {
+		custodyGroupCountEntry := enr.WithEntry(custodyGroupCountEnrKey, custodyGroupCount)
+		localNode.Set(custodyGroupCountEntry)
+	}
+
 	s.metaData = wrapper.WrappedMetadataV1(&pb.MetaDataV1{
 		SeqNumber: s.metaData.SequenceNumber() + 1,
 		Attnets:   bitVAtt,
@@ -421,10 +433,8 @@ func (s *Service) updateSubnetRecordWithMetadataV3(
 	localNode.Set(syncSubnetsEntry)
 	localNode.Set(custodyGroupCountEntry)
 
-	newSeqNumber := s.metaData.SequenceNumber() + 1
-
 	s.metaData = wrapper.WrappedMetadataV2(&pb.MetaDataV2{
-		SeqNumber:         newSeqNumber,
+		SeqNumber:         s.metaData.SequenceNumber() + 1,
 		Attnets:           bitVAtt,
 		Syncnets:          bitVSync,
 		CustodyGroupCount: custodyGroupCount,

beacon-chain/p2p/subnets_test.go

@@ -74,6 +74,7 @@ func TestStartDiscV5_FindAndDialPeersWithSubnet(t *testing.T) {
 		cfg:                   &Config{UDPPort: 2000, TCPPort: 3000, QUICPort: 3000, DisableLivenessCheck: true, PingInterval: testPingInterval},
 		genesisTime:           genesisTime,
 		genesisValidatorsRoot: genesisValidatorsRoot,
+		custodyInfo:           &custodyInfo{},
 	}
 
 	bootNodeForkDigest, err := bootNodeService.currentForkDigest()
@@ -108,6 +109,7 @@ func TestStartDiscV5_FindAndDialPeersWithSubnet(t *testing.T) {
 
 		service.genesisTime = genesisTime
 		service.genesisValidatorsRoot = genesisValidatorsRoot
+		service.custodyInfo = &custodyInfo{}
 
 		nodeForkDigest, err := service.currentForkDigest()
 		require.NoError(t, err)
@@ -157,6 +159,7 @@ func TestStartDiscV5_FindAndDialPeersWithSubnet(t *testing.T) {
 
 	service.genesisTime = genesisTime
 	service.genesisValidatorsRoot = genesisValidatorsRoot
+	service.custodyInfo = &custodyInfo{}
 
 	service.Start()
 	defer func() {

beacon-chain/p2p/testing/BUILD.bazel

@@ -15,6 +15,7 @@ go_library(
     importpath = "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing",
     visibility = [
         "//beacon-chain:__subpackages__",
+        "//testing:__subpackages__",
     ],
     deps = [
         "//beacon-chain/core/peerdas:go_default_library",
@@ -24,6 +25,7 @@ go_library(
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/interfaces:go_default_library",
+        "//consensus-types/primitives:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/metadata:go_default_library",
         "//testing/require:go_default_library",

beacon-chain/p2p/testing/fuzz_p2p.go

@@ -7,6 +7,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1/metadata"
 	"github.com/ethereum/go-ethereum/p2p/enode"
@@ -196,6 +197,22 @@ func (*FakeP2P) InterceptUpgraded(network.Conn) (allow bool, reason control.Disc
 	return true, 0
 }
 
+// EarliestAvailableSlot -- fake.
+func (*FakeP2P) EarliestAvailableSlot() (primitives.Slot, error) {
+	return 0, nil
+}
+
+// CustodyGroupCount -- fake.
+func (*FakeP2P) CustodyGroupCount() (uint64, error) {
+	return 0, nil
+}
+
+// UpdateCustodyInfo -- fake.
+func (s *FakeP2P) UpdateCustodyInfo(earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error) {
+	return earliestAvailableSlot, custodyGroupCount, nil
+}
+
+// CustodyGroupCountFromPeer -- fake.
 func (*FakeP2P) CustodyGroupCountFromPeer(peer.ID) uint64 {
 	return 0
 }

beacon-chain/p2p/testing/mock_peersprovider.go

@@ -65,7 +65,7 @@ func (m *MockPeersProvider) Peers() *peers.Status {
 		}
 		m.peers.Add(createENR(), id0, ma0, network.DirInbound)
 		m.peers.SetConnectionState(id0, peers.Connected)
-		m.peers.SetChainState(id0, &pb.Status{FinalizedEpoch: 10})
+		m.peers.SetChainState(id0, &pb.StatusV2{FinalizedEpoch: 10})
 		id1, err := peer.Decode(MockRawPeerId1)
 		if err != nil {
 			log.WithError(err).Debug("Cannot decode")
@@ -76,7 +76,7 @@ func (m *MockPeersProvider) Peers() *peers.Status {
 		}
 		m.peers.Add(createENR(), id1, ma1, network.DirOutbound)
 		m.peers.SetConnectionState(id1, peers.Connected)
-		m.peers.SetChainState(id1, &pb.Status{FinalizedEpoch: 11})
+		m.peers.SetChainState(id1, &pb.StatusV2{FinalizedEpoch: 11})
 	}
 	return m.peers
 }

beacon-chain/p2p/testing/p2p.go

@@ -6,6 +6,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -17,6 +18,7 @@ import (
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1/metadata"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
@@ -48,16 +50,19 @@ const (
 
 // TestP2P represents a p2p implementation that can be used for testing.
 type TestP2P struct {
-	t               *testing.T
-	BHost           host.Host
-	EnodeID         enode.ID
-	pubsub          *pubsub.PubSub
-	joinedTopics    map[string]*pubsub.Topic
-	BroadcastCalled atomic.Bool
-	DelaySend       bool
-	Digest          [4]byte
-	peers           *peers.Status
-	LocalMetadata   metadata.Metadata
+	t                     *testing.T
+	BHost                 host.Host
+	EnodeID               enode.ID
+	pubsub                *pubsub.PubSub
+	joinedTopics          map[string]*pubsub.Topic
+	BroadcastCalled       atomic.Bool
+	DelaySend             bool
+	Digest                [4]byte
+	peers                 *peers.Status
+	LocalMetadata         metadata.Metadata
+	custodyInfoMut        sync.RWMutex // protects custodyGroupCount and earliestAvailableSlot
+	earliestAvailableSlot primitives.Slot
+	custodyGroupCount     uint64
 }
 
 // NewTestP2P initializes a new p2p test service.
@@ -461,6 +466,34 @@ func (*TestP2P) InterceptUpgraded(network.Conn) (allow bool, reason control.Disc
 	return true, 0
 }
 
+// EarliestAvailableSlot .
+func (s *TestP2P) EarliestAvailableSlot() (primitives.Slot, error) {
+	s.custodyInfoMut.RLock()
+	defer s.custodyInfoMut.RUnlock()
+
+	return s.earliestAvailableSlot, nil
+}
+
+// CustodyGroupCount .
+func (s *TestP2P) CustodyGroupCount() (uint64, error) {
+	s.custodyInfoMut.RLock()
+	defer s.custodyInfoMut.RUnlock()
+
+	return s.custodyGroupCount, nil
+}
+
+// UpdateCustodyInfo .
+func (s *TestP2P) UpdateCustodyInfo(earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error) {
+	s.custodyInfoMut.Lock()
+	defer s.custodyInfoMut.Unlock()
+
+	s.earliestAvailableSlot = earliestAvailableSlot
+	s.custodyGroupCount = custodyGroupCount
+
+	return s.earliestAvailableSlot, s.custodyGroupCount, nil
+}
+
+// CustodyGroupCountFromPeer .
 func (s *TestP2P) CustodyGroupCountFromPeer(pid peer.ID) uint64 {
 	// By default, we assume the peer custodies the minimum number of groups.
 	custodyRequirement := params.BeaconConfig().CustodyRequirement

beacon-chain/rpc/eth/beacon/handlers.go

@@ -1311,7 +1311,7 @@ func (s *Server) GetCommittees(w http.ResponseWriter, r *http.Request) {
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 
@@ -1492,7 +1492,7 @@ func (s *Server) GetFinalityCheckpoints(w http.ResponseWriter, r *http.Request)
 	}
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 	blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -1666,7 +1666,7 @@ func (s *Server) GetPendingConsolidations(w http.ResponseWriter, r *http.Request
 	} else {
 		isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 		if err != nil {
-			httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+			helpers.HandleIsOptimisticError(w, err)
 			return
 		}
 		blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -1722,7 +1722,7 @@ func (s *Server) GetPendingDeposits(w http.ResponseWriter, r *http.Request) {
 	} else {
 		isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 		if err != nil {
-			httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+			helpers.HandleIsOptimisticError(w, err)
 			return
 		}
 		blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -1778,7 +1778,7 @@ func (s *Server) GetPendingPartialWithdrawals(w http.ResponseWriter, r *http.Req
 	} else {
 		isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 		if err != nil {
-			httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+			helpers.HandleIsOptimisticError(w, err)
 			return
 		}
 		blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -1831,7 +1831,7 @@ func (s *Server) GetProposerLookahead(w http.ResponseWriter, r *http.Request) {
 	} else {
 		isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 		if err != nil {
-			httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+			helpers.HandleIsOptimisticError(w, err)
 			return
 		}
 		blockRoot, err := st.LatestBlockHeader().HashTreeRoot()

beacon-chain/rpc/eth/beacon/handlers_pool_test.go

@@ -1103,9 +1103,9 @@ func TestSubmitSyncCommitteeSignatures(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, 1, len(msgsInPool))
 		assert.Equal(t, primitives.Slot(1), msgsInPool[0].Slot)
-		assert.Equal(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2", hexutil.Encode(msgsInPool[0].BlockRoot))
+		assert.Equal(t, "0xbacd20f09da907734434f052bd4c9503aa16bab1960e89ea20610d08d064481c", hexutil.Encode(msgsInPool[0].BlockRoot))
 		assert.Equal(t, primitives.ValidatorIndex(1), msgsInPool[0].ValidatorIndex)
-		assert.Equal(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505", hexutil.Encode(msgsInPool[0].Signature))
+		assert.Equal(t, "0xb591bd4ca7d745b6e027879645d7c014fecb8c58631af070f7607acc0c1c948a5102a33267f0e4ba41a85b254b07df91185274375b2e6436e37e81d2fd46cb3751f5a6c86efb7499c1796c0c17e122a54ac067bb0f5ff41f3241659cceb0c21c", hexutil.Encode(msgsInPool[0].Signature))
 		assert.Equal(t, true, broadcaster.BroadcastCalled.Load())
 	})
 	t.Run("multiple", func(t *testing.T) {
@@ -2497,23 +2497,23 @@ var (
 	singleSyncCommitteeMsg = `[
   {
     "slot": "1",
-    "beacon_block_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "beacon_block_root": "0xbacd20f09da907734434f052bd4c9503aa16bab1960e89ea20610d08d064481c",
     "validator_index": "1",
-    "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
+    "signature": "0xb591bd4ca7d745b6e027879645d7c014fecb8c58631af070f7607acc0c1c948a5102a33267f0e4ba41a85b254b07df91185274375b2e6436e37e81d2fd46cb3751f5a6c86efb7499c1796c0c17e122a54ac067bb0f5ff41f3241659cceb0c21c"
   }
 ]`
 	multipleSyncCommitteeMsg = `[
   {
     "slot": "1",
-    "beacon_block_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "beacon_block_root": "0xbacd20f09da907734434f052bd4c9503aa16bab1960e89ea20610d08d064481c",
     "validator_index": "1",
-    "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
+    "signature": "0xb591bd4ca7d745b6e027879645d7c014fecb8c58631af070f7607acc0c1c948a5102a33267f0e4ba41a85b254b07df91185274375b2e6436e37e81d2fd46cb3751f5a6c86efb7499c1796c0c17e122a54ac067bb0f5ff41f3241659cceb0c21c"
   },
   {
     "slot": "2",
-    "beacon_block_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "beacon_block_root": "0x2757f6fd8590925cd000a86a3e543f98a93eae23781783a33e34504729a8ad0c",
     "validator_index": "1",
-    "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
+    "signature": "0x99dfe11b6c8b306d2c72eb891926d37922d226ea8e1e7484d6c30fab746494f192b0daa3e40c13f1e335b35238f3362c113455a329b1fab0bc500bc47f643786f49e151d5b5052afb51af57ba5aa34a6051dc90ee4de83a26eb54a895061d89a"
   }
 ]`
 	// signature is invalid
@@ -2523,6 +2523,18 @@ var (
     "beacon_block_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
     "validator_index": "1",
     "signature": "foo"
+  },
+  {
+	"slot": "1121",
+	"beacon_block_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+	"validator_index": "1",
+	"signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
+  },
+  {
+	"slot": "1121",
+	"beacon_block_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+	"validator_index": "2",
+	"signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
   }
 ]`
 	// signatures are invalid

beacon-chain/rpc/eth/beacon/handlers_state.go

@@ -56,7 +56,7 @@ func (s *Server) GetStateRoot(w http.ResponseWriter, r *http.Request) {
 	}
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 	blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -125,7 +125,7 @@ func (s *Server) GetRandao(w http.ResponseWriter, r *http.Request) {
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 
@@ -227,7 +227,7 @@ func (s *Server) GetSyncCommittees(w http.ResponseWriter, r *http.Request) {
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 

beacon-chain/rpc/eth/beacon/handlers_validator.go

@@ -44,7 +44,7 @@ func (s *Server) GetValidators(w http.ResponseWriter, r *http.Request) {
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 	blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -222,7 +222,7 @@ func (s *Server) GetValidator(w http.ResponseWriter, r *http.Request) {
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 	blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -258,7 +258,7 @@ func (s *Server) GetValidatorBalances(w http.ResponseWriter, r *http.Request) {
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 	blockRoot, err := st.LatestBlockHeader().HashTreeRoot()
@@ -419,7 +419,7 @@ func (s *Server) getValidatorIdentitiesJSON(
 ) {
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateId), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 	blockRoot, err := st.LatestBlockHeader().HashTreeRoot()

beacon-chain/rpc/eth/debug/handlers.go

@@ -46,7 +46,7 @@ func (s *Server) getBeaconStateV2(ctx context.Context, w http.ResponseWriter, id
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, id, s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		httputil.HandleError(w, "Could not check if state is optimistic: "+err.Error(), http.StatusInternalServerError)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 	blockRoot, err := st.LatestBlockHeader().HashTreeRoot()

beacon-chain/rpc/eth/helpers/BUILD.bazel

@@ -12,6 +12,7 @@ go_library(
     deps = [
         "//beacon-chain/blockchain:go_default_library",
         "//beacon-chain/db:go_default_library",
+        "//beacon-chain/rpc/eth/shared:go_default_library",
         "//beacon-chain/rpc/lookup:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/stategen:go_default_library",
@@ -21,6 +22,7 @@ go_library(
         "//consensus-types/primitives:go_default_library",
         "//consensus-types/validator:go_default_library",
         "//encoding/bytesutil:go_default_library",
+        "//network/httputil:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
@@ -40,6 +42,7 @@ go_test(
         "//beacon-chain/blockchain/testing:go_default_library",
         "//beacon-chain/db/testing:go_default_library",
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
+        "//beacon-chain/rpc/lookup:go_default_library",
         "//beacon-chain/rpc/testutil:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",
@@ -57,5 +60,6 @@ go_test(
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
     ],
 )

beacon-chain/rpc/eth/helpers/sync.go

@@ -3,15 +3,18 @@ package helpers
 import (
 	"bytes"
 	"context"
+	"net/http"
 	"strconv"
 	"strings"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/rpc/eth/shared"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/rpc/lookup"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/network/httputil"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
@@ -127,7 +130,7 @@ func isStateRootOptimistic(
 ) (bool, error) {
 	st, err := stateFetcher.State(ctx, stateId)
 	if err != nil {
-		return true, errors.Wrap(err, "could not fetch state")
+		return true, lookup.NewFetchStateError(err)
 	}
 	if st.Slot() == chainInfo.HeadSlot() {
 		return optimisticModeFetcher.IsOptimistic(ctx)
@@ -152,3 +155,14 @@ func isStateRootOptimistic(
 	// No block matching requested state root, return true.
 	return true, nil
 }
+
+// HandleIsOptimisticError adds more fine grained handling of the IsOptimistic function's error and sets the error in the response writer
+func HandleIsOptimisticError(w http.ResponseWriter, err error) {
+	var fetchErr *lookup.FetchStateError
+	if errors.As(err, &fetchErr) {
+		shared.WriteStateFetchError(w, err)
+		return
+	}
+	httputil.HandleError(w, "Could not check optimistic status: "+err.Error(), http.StatusInternalServerError)
+	return
+}

beacon-chain/rpc/eth/helpers/sync_test.go

@@ -1,12 +1,15 @@
 package helpers
 
 import (
+	"net/http"
+	"net/http/httptest"
 	"strconv"
 	"testing"
 
 	chainmock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
 	dbtest "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
 	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/rpc/lookup"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/rpc/testutil"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	state_native "github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native"
@@ -21,6 +24,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/pkg/errors"
 )
 
 func TestIsOptimistic(t *testing.T) {
@@ -226,6 +230,25 @@ func TestIsOptimistic(t *testing.T) {
 			require.NoError(t, err)
 			assert.Equal(t, true, o)
 		})
+		t.Run("State not found", func(t *testing.T) {
+			b, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlock())
+			require.NoError(t, err)
+			b.SetStateRoot(bytesutil.PadTo([]byte("root"), 32))
+			db := dbtest.SetupDB(t)
+			require.NoError(t, db.SaveBlock(ctx, b))
+			chainSt, err := util.NewBeaconState()
+			require.NoError(t, err)
+			require.NoError(t, chainSt.SetSlot(fieldparams.SlotsPerEpoch))
+			bRoot, err := b.Block().HashTreeRoot()
+			require.NoError(t, err)
+			cs := &chainmock.ChainService{State: chainSt, OptimisticRoots: map[[32]byte]bool{bRoot: true}}
+			mf := &testutil.MockStater{
+				CustomError: lookup.NewFetchStateError(nil),
+			}
+			_, err = IsOptimistic(ctx, []byte(hexutil.Encode(bytesutil.PadTo([]byte("root"), 32))), cs, mf, cs, db)
+			var fetchErr *lookup.FetchStateError
+			require.Equal(t, true, errors.As(err, &fetchErr))
+		})
 	})
 	t.Run("slot", func(t *testing.T) {
 		t.Run("head is not optimistic", func(t *testing.T) {
@@ -370,3 +393,25 @@ func prepareForkchoiceState(
 	roblock, err := blocks.NewROBlockWithRoot(signed, blockRoot)
 	return st, roblock, err
 }
+
+func TestHandleIsOptimisticError(t *testing.T) {
+	t.Run("fetch-state error handled as 404", func(t *testing.T) {
+		rr := httptest.NewRecorder()
+		notFoundErr := lookup.StateNotFoundError{}
+		fetchErr := lookup.NewFetchStateError(&notFoundErr)
+		HandleIsOptimisticError(rr, fetchErr)
+
+		require.Equal(t, http.StatusNotFound, rr.Code)
+		require.StringContains(t, notFoundErr.Error(), rr.Body.String())
+	})
+
+	t.Run("generic error handled as 500", func(t *testing.T) {
+		rr := httptest.NewRecorder()
+		genericErr := errors.New("boom")
+
+		HandleIsOptimisticError(rr, genericErr)
+
+		require.Equal(t, http.StatusInternalServerError, rr.Code)
+		require.StringContains(t, "Could not check optimistic status: boom", rr.Body.String())
+	})
+}

beacon-chain/rpc/eth/light-client/BUILD.bazel

@@ -33,9 +33,11 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//api/server/structs:go_default_library",
+        "//async/event:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/db/testing:go_default_library",
+        "//beacon-chain/p2p/testing:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",

beacon-chain/rpc/eth/light-client/handlers_test.go

@@ -11,9 +11,11 @@ import (
 	"testing"
 
 	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	"github.com/OffchainLabs/prysm/v6/async/event"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	dbtesting "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
+	p2ptesting "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
@@ -53,7 +55,7 @@ func TestLightClientHandler_GetLightClientBootstrap(t *testing.T) {
 			require.NoError(t, err)
 
 			db := dbtesting.SetupDB(t)
-			lcStore := lightclient.NewLightClientStore(db)
+			lcStore := lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed))
 
 			err = db.SaveLightClientBootstrap(l.Ctx, blockRoot[:], bootstrap)
 			require.NoError(t, err)
@@ -97,7 +99,7 @@ func TestLightClientHandler_GetLightClientBootstrap(t *testing.T) {
 			require.NoError(t, err)
 
 			db := dbtesting.SetupDB(t)
-			lcStore := lightclient.NewLightClientStore(db)
+			lcStore := lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed))
 
 			err = db.SaveLightClientBootstrap(l.Ctx, blockRoot[:], bootstrap)
 			require.NoError(t, err)
@@ -141,7 +143,7 @@ func TestLightClientHandler_GetLightClientBootstrap(t *testing.T) {
 
 	t.Run("no bootstrap found", func(t *testing.T) {
 		s := &Server{
-			LCStore: lightclient.NewLightClientStore(dbtesting.SetupDB(t)),
+			LCStore: lightclient.NewLightClientStore(dbtesting.SetupDB(t), &p2ptesting.FakeP2P{}, new(event.Feed)),
 		}
 		request := httptest.NewRequest("GET", "http://foo.com/", nil)
 		request.SetPathValue("block_root", hexutil.Encode([]byte{0x00, 0x01, 0x02}))
@@ -184,7 +186,7 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 				}
 
 				s := &Server{
-					LCStore: lightclient.NewLightClientStore(db),
+					LCStore: lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed)),
 				}
 
 				updatePeriod := startPeriod
@@ -325,7 +327,7 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 
 				db := dbtesting.SetupDB(t)
 				s := &Server{
-					LCStore: lightclient.NewLightClientStore(db),
+					LCStore: lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed)),
 				}
 
 				updates := make([]interfaces.LightClientUpdate, 2)
@@ -445,7 +447,7 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 
 		db := dbtesting.SetupDB(t)
 		s := &Server{
-			LCStore: lightclient.NewLightClientStore(db),
+			LCStore: lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed)),
 		}
 
 		updates := make([]interfaces.LightClientUpdate, 3)
@@ -492,7 +494,7 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 
 		db := dbtesting.SetupDB(t)
 		s := &Server{
-			LCStore: lightclient.NewLightClientStore(db),
+			LCStore: lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed)),
 		}
 
 		updates := make([]interfaces.LightClientUpdate, 3)
@@ -536,7 +538,7 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 	t.Run("start period before altair", func(t *testing.T) {
 		db := dbtesting.SetupDB(t)
 		s := &Server{
-			LCStore: lightclient.NewLightClientStore(db),
+			LCStore: lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed)),
 		}
 		startPeriod := 0
 		url := fmt.Sprintf("http://foo.com/?count=128&start_period=%d", startPeriod)
@@ -559,7 +561,7 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 		t.Run("missing update in the middle", func(t *testing.T) {
 			db := dbtesting.SetupDB(t)
 			s := &Server{
-				LCStore: lightclient.NewLightClientStore(db),
+				LCStore: lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed)),
 			}
 
 			updates := make([]interfaces.LightClientUpdate, 3)
@@ -603,7 +605,7 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 		t.Run("missing update at the beginning", func(t *testing.T) {
 			db := dbtesting.SetupDB(t)
 			s := &Server{
-				LCStore: lightclient.NewLightClientStore(db),
+				LCStore: lightclient.NewLightClientStore(db, &p2ptesting.FakeP2P{}, new(event.Feed)),
 			}
 
 			updates := make([]interfaces.LightClientUpdate, 3)
@@ -663,8 +665,8 @@ func TestLightClientHandler_GetLightClientFinalityUpdate(t *testing.T) {
 			update, err := lightclient.NewLightClientFinalityUpdateFromBeaconState(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
 			require.NoError(t, err)
 
-			s := &Server{LCStore: &lightclient.Store{}}
-			s.LCStore.SetLastFinalityUpdate(update)
+			s := &Server{LCStore: lightclient.NewLightClientStore(dbtesting.SetupDB(t), &p2ptesting.FakeP2P{}, new(event.Feed))}
+			s.LCStore.SetLastFinalityUpdate(update, false)
 
 			request := httptest.NewRequest("GET", "http://foo.com", nil)
 			writer := httptest.NewRecorder()
@@ -688,8 +690,8 @@ func TestLightClientHandler_GetLightClientFinalityUpdate(t *testing.T) {
 			update, err := lightclient.NewLightClientFinalityUpdateFromBeaconState(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
 			require.NoError(t, err)
 
-			s := &Server{LCStore: &lightclient.Store{}}
-			s.LCStore.SetLastFinalityUpdate(update)
+			s := &Server{LCStore: lightclient.NewLightClientStore(dbtesting.SetupDB(t), &p2ptesting.FakeP2P{}, new(event.Feed))}
+			s.LCStore.SetLastFinalityUpdate(update, false)
 
 			request := httptest.NewRequest("GET", "http://foo.com", nil)
 			request.Header.Add("Accept", "application/octet-stream")
@@ -727,7 +729,7 @@ func TestLightClientHandler_GetLightClientOptimisticUpdate(t *testing.T) {
 	helpers.ClearCache()
 
 	t.Run("no update", func(t *testing.T) {
-		s := &Server{LCStore: &lightclient.Store{}}
+		s := &Server{LCStore: lightclient.NewLightClientStore(dbtesting.SetupDB(t), &p2ptesting.FakeP2P{}, new(event.Feed))}
 
 		request := httptest.NewRequest("GET", "http://foo.com", nil)
 		writer := httptest.NewRecorder()
@@ -743,8 +745,8 @@ func TestLightClientHandler_GetLightClientOptimisticUpdate(t *testing.T) {
 			update, err := lightclient.NewLightClientOptimisticUpdateFromBeaconState(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock)
 			require.NoError(t, err)
 
-			s := &Server{LCStore: &lightclient.Store{}}
-			s.LCStore.SetLastOptimisticUpdate(update)
+			s := &Server{LCStore: lightclient.NewLightClientStore(dbtesting.SetupDB(t), &p2ptesting.FakeP2P{}, new(event.Feed))}
+			s.LCStore.SetLastOptimisticUpdate(update, false)
 
 			request := httptest.NewRequest("GET", "http://foo.com", nil)
 			writer := httptest.NewRecorder()
@@ -767,8 +769,8 @@ func TestLightClientHandler_GetLightClientOptimisticUpdate(t *testing.T) {
 			update, err := lightclient.NewLightClientOptimisticUpdateFromBeaconState(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock)
 			require.NoError(t, err)
 
-			s := &Server{LCStore: &lightclient.Store{}}
-			s.LCStore.SetLastOptimisticUpdate(update)
+			s := &Server{LCStore: lightclient.NewLightClientStore(dbtesting.SetupDB(t), &p2ptesting.FakeP2P{}, new(event.Feed))}
+			s.LCStore.SetLastOptimisticUpdate(update, false)
 
 			request := httptest.NewRequest("GET", "http://foo.com", nil)
 			request.Header.Add("Accept", "application/octet-stream")

beacon-chain/rpc/lookup/stater.go

@@ -21,6 +21,27 @@ import (
 	"github.com/pkg/errors"
 )
 
+type FetchStateError struct {
+	message string
+	cause   error
+}
+
+func NewFetchStateError(cause error) *FetchStateError {
+	return &FetchStateError{
+		message: "could not fetch state",
+		cause:   cause,
+	}
+}
+
+func (e *FetchStateError) Error() string {
+	if e.cause != nil {
+		return e.message + ": " + e.cause.Error()
+	}
+	return e.message
+}
+
+func (e *FetchStateError) Unwrap() error { return e.cause }
+
 // StateIdParseError represents an error scenario where a state ID could not be parsed.
 type StateIdParseError struct {
 	message string

beacon-chain/rpc/prysm/beacon/validator_count.go

@@ -56,11 +56,7 @@ func (s *Server) GetValidatorCount(w http.ResponseWriter, r *http.Request) {
 
 	isOptimistic, err := helpers.IsOptimistic(ctx, []byte(stateID), s.OptimisticModeFetcher, s.Stater, s.ChainInfoFetcher, s.BeaconDB)
 	if err != nil {
-		errJson := &httputil.DefaultJsonError{
-			Message: fmt.Sprintf("could not check if slot's block is optimistic: %v", err),
-			Code:    http.StatusInternalServerError,
-		}
-		httputil.WriteError(w, errJson)
+		helpers.HandleIsOptimisticError(w, err)
 		return
 	}
 

beacon-chain/rpc/prysm/v1alpha1/debug/p2p.go

@@ -109,6 +109,8 @@ func (ds *Server) getPeer(pid peer.ID) (*ethpb.DebugPeerResponse, error) {
 			peerInfo.MetadataV0 = metadata.MetadataObjV0()
 		case metadata.MetadataObjV1() != nil:
 			peerInfo.MetadataV1 = metadata.MetadataObjV1()
+		case metadata.MetadataObjV2() != nil:
+			peerInfo.MetadataV2 = metadata.MetadataObjV2()
 		}
 	}
 	addresses := peerStore.Addrs(pid)
@@ -127,7 +129,7 @@ func (ds *Server) getPeer(pid peer.ID) (*ethpb.DebugPeerResponse, error) {
 	if err != nil {
 		// In the event chain state is non existent, we
 		// initialize with the zero value.
-		pStatus = new(ethpb.Status)
+		pStatus = new(ethpb.StatusV2)
 	}
 	lastUpdated, err := peers.ChainStateLastUpdated(pid)
 	if err != nil {
@@ -150,6 +152,16 @@ func (ds *Server) getPeer(pid peer.ID) (*ethpb.DebugPeerResponse, error) {
 		BehaviourPenalty:   float32(bPenalty),
 		ValidationError:    errorToString(peers.Scorers().ValidationError(pid)),
 	}
+
+	// Convert statusV2 into status
+	peerStatus := &ethpb.Status{
+		ForkDigest:     pStatus.ForkDigest,
+		FinalizedRoot:  pStatus.FinalizedRoot,
+		FinalizedEpoch: pStatus.FinalizedEpoch,
+		HeadRoot:       pStatus.HeadRoot,
+		HeadSlot:       pStatus.HeadSlot,
+	}
+
 	return &ethpb.DebugPeerResponse{
 		ListeningAddresses: stringAddrs,
 		Direction:          pbDirection,
@@ -157,7 +169,7 @@ func (ds *Server) getPeer(pid peer.ID) (*ethpb.DebugPeerResponse, error) {
 		PeerId:             pid.String(),
 		Enr:                enr,
 		PeerInfo:           peerInfo,
-		PeerStatus:         pStatus,
+		PeerStatus:         peerStatus,
 		LastUpdated:        unixTime,
 		ScoreInfo:          scoreInfo,
 	}, nil

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_bellatrix.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"fmt"
 	"math/big"
-	"strings"
 	"time"
 
 	"github.com/OffchainLabs/prysm/v6/api/client/builder"
@@ -19,7 +18,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/encoding/ssz"
 	"github.com/OffchainLabs/prysm/v6/monitoring/tracing"
 	"github.com/OffchainLabs/prysm/v6/monitoring/tracing/trace"
-	"github.com/OffchainLabs/prysm/v6/network/forks"
 	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
@@ -220,16 +218,10 @@ func (vs *Server) getPayloadHeaderFromBuilder(
 	if signedBid == nil || signedBid.IsNil() {
 		return nil, errors.New("builder returned nil bid")
 	}
-	fork, err := forks.Fork(slots.ToEpoch(slot))
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to get fork information")
-	}
-	forkName, ok := params.BeaconConfig().ForkVersionNames[bytesutil.ToBytes4(fork.CurrentVersion)]
-	if !ok {
-		return nil, errors.New("unable to find current fork in schedule")
-	}
-	if !strings.EqualFold(version.String(signedBid.Version()), forkName) {
-		return nil, fmt.Errorf("builder bid response version: %d is different from head block version: %d for epoch %d", signedBid.Version(), b.Version(), slots.ToEpoch(slot))
+	bidVersion := signedBid.Version()
+	headBlockVersion := b.Version()
+	if !isVersionCompatible(bidVersion, headBlockVersion) {
+		return nil, fmt.Errorf("builder bid response version: %d is not compatible with head block version: %d for epoch %d", bidVersion, headBlockVersion, slots.ToEpoch(slot))
 	}
 
 	bid, err := signedBid.Message()
@@ -466,3 +458,19 @@ func expectedGasLimit(parentGasLimit, proposerGasLimit uint64) uint64 {
 	}
 	return proposerGasLimit
 }
+
+// isVersionCompatible checks if a builder bid version is compatible with the head block version.
+func isVersionCompatible(bidVersion, headBlockVersion int) bool {
+	// Exact version match is always compatible
+	if bidVersion == headBlockVersion {
+		return true
+	}
+
+	// Allow Electra bids for Fulu blocks - they have compatible payload formats
+	if bidVersion == version.Electra && headBlockVersion == version.Fulu {
+		return true
+	}
+
+	// For all other cases, require exact version match
+	return false
+}

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_bellatrix_test.go

@@ -25,6 +25,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/encoding/ssz"
 	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
@@ -156,7 +157,7 @@ func TestServer_setExecutionData(t *testing.T) {
 			HasConfigured: true,
 			Cfg:           &builderTest.Config{BeaconDB: beaconDB},
 		}
-		wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockBellatrix())
+		wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockCapella())
 		require.NoError(t, err)
 		chain := &blockchainTest.ChainService{ForkChoiceStore: doublylinkedtree.New(), Genesis: time.Now(), Block: wb}
 		vs.ForkchoiceFetcher = chain
@@ -973,7 +974,7 @@ func TestServer_getPayloadHeader(t *testing.T) {
 					return wb
 				}(),
 			},
-			err: "is different from head block version",
+			err: "builder bid response version: 3 is not compatible with head block version: 2 for epoch 1",
 		},
 		{
 			name: "different bid version during hard fork",
@@ -982,7 +983,7 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			},
 			fetcher: &blockchainTest.ChainService{
 				Block: func() interfaces.ReadOnlySignedBeaconBlock {
-					wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockBellatrix())
+					wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockCapella())
 					require.NoError(t, err)
 					wb.SetSlot(primitives.Slot(fakeCapellaEpoch) * params.BeaconConfig().SlotsPerEpoch)
 					return wb
@@ -1005,6 +1006,86 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			},
 			err: "incorrect header gas limit 30000000 != 31000000",
 		},
+		{
+			name: "electra bid with fulu head block - compatible",
+			mock: func() *builderTest.MockBuilderService {
+				// Create Electra bid
+				requests := &v1.ExecutionRequests{
+					Deposits: []*v1.DepositRequest{
+						{
+							Pubkey:                bytesutil.PadTo([]byte{byte('a')}, fieldparams.BLSPubkeyLength),
+							WithdrawalCredentials: bytesutil.PadTo([]byte{byte('b')}, fieldparams.RootLength),
+							Amount:                params.BeaconConfig().MinActivationBalance,
+							Signature:             bytesutil.PadTo([]byte{byte('c')}, fieldparams.BLSSignatureLength),
+							Index:                 0,
+						},
+					},
+					Withdrawals: []*v1.WithdrawalRequest{
+						{
+							SourceAddress:   bytesutil.PadTo([]byte{byte('d')}, common.AddressLength),
+							ValidatorPubkey: bytesutil.PadTo([]byte{byte('e')}, fieldparams.BLSPubkeyLength),
+							Amount:          params.BeaconConfig().MinActivationBalance,
+						},
+					},
+					Consolidations: []*v1.ConsolidationRequest{
+						{
+							SourceAddress: bytesutil.PadTo([]byte{byte('f')}, common.AddressLength),
+							SourcePubkey:  bytesutil.PadTo([]byte{byte('g')}, fieldparams.BLSPubkeyLength),
+							TargetPubkey:  bytesutil.PadTo([]byte{byte('h')}, fieldparams.BLSPubkeyLength),
+						},
+					},
+				}
+
+				electraBid := &ethpb.BuilderBidElectra{
+					Header: &v1.ExecutionPayloadHeaderDeneb{
+						FeeRecipient:     make([]byte, fieldparams.FeeRecipientLength),
+						StateRoot:        make([]byte, fieldparams.RootLength),
+						ReceiptsRoot:     make([]byte, fieldparams.RootLength),
+						LogsBloom:        make([]byte, fieldparams.LogsBloomLength),
+						PrevRandao:       make([]byte, fieldparams.RootLength),
+						BaseFeePerGas:    make([]byte, fieldparams.RootLength),
+						BlockHash:        make([]byte, fieldparams.RootLength),
+						TransactionsRoot: bytesutil.PadTo([]byte{1}, fieldparams.RootLength),
+						ParentHash:       params.BeaconConfig().ZeroHash[:],
+						Timestamp:        uint64(ti.Unix()),
+						BlockNumber:      2,
+						WithdrawalsRoot:  make([]byte, fieldparams.RootLength),
+						BlobGasUsed:      123,
+						ExcessBlobGas:    456,
+						GasLimit:         gasLimit,
+					},
+					Pubkey:             sk.PublicKey().Marshal(),
+					Value:              bytesutil.PadTo([]byte{1, 2, 3}, 32),
+					BlobKzgCommitments: [][]byte{bytesutil.PadTo([]byte{2}, fieldparams.BLSPubkeyLength)},
+					ExecutionRequests:  requests,
+				}
+
+				d := params.BeaconConfig().DomainApplicationBuilder
+				domain, err := signing.ComputeDomain(d, nil, nil)
+				require.NoError(t, err)
+				sr, err := signing.ComputeSigningRoot(electraBid, domain)
+				require.NoError(t, err)
+
+				sBidElectra := &ethpb.SignedBuilderBidElectra{
+					Message:   electraBid,
+					Signature: sk.Sign(sr[:]).Marshal(),
+				}
+
+				return &builderTest.MockBuilderService{
+					BidElectra: sBidElectra,
+				}
+			}(),
+			fetcher: &blockchainTest.ChainService{
+				Block: func() interfaces.ReadOnlySignedBeaconBlock {
+					// Create Fulu head block
+					wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockFulu())
+					require.NoError(t, err)
+					wb.SetSlot(primitives.Slot(params.BeaconConfig().BellatrixForkEpoch) * params.BeaconConfig().SlotsPerEpoch)
+					return wb
+				}(),
+			},
+			// Should succeed because Electra bids are compatible with Fulu head blocks
+		},
 	}
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
@@ -1222,3 +1303,107 @@ func Test_expectedGasLimit(t *testing.T) {
 		})
 	}
 }
+
+func TestIsVersionCompatible(t *testing.T) {
+
+	tests := []struct {
+		name             string
+		bidVersion       int
+		headBlockVersion int
+		want             bool
+	}{
+		{
+			name:             "Exact version match - Bellatrix",
+			bidVersion:       version.Bellatrix,
+			headBlockVersion: version.Bellatrix,
+			want:             true,
+		},
+		{
+			name:             "Exact version match - Capella",
+			bidVersion:       version.Capella,
+			headBlockVersion: version.Capella,
+			want:             true,
+		},
+		{
+			name:             "Exact version match - Deneb",
+			bidVersion:       version.Deneb,
+			headBlockVersion: version.Deneb,
+			want:             true,
+		},
+		{
+			name:             "Exact version match - Electra",
+			bidVersion:       version.Electra,
+			headBlockVersion: version.Electra,
+			want:             true,
+		},
+		{
+			name:             "Exact version match - Fulu",
+			bidVersion:       version.Fulu,
+			headBlockVersion: version.Fulu,
+			want:             true,
+		},
+		{
+			name:             "Electra bid with Fulu head block - Compatible",
+			bidVersion:       version.Electra,
+			headBlockVersion: version.Fulu,
+			want:             true,
+		},
+		{
+			name:             "Fulu bid with Electra head block - Not compatible",
+			bidVersion:       version.Fulu,
+			headBlockVersion: version.Electra,
+			want:             false,
+		},
+		{
+			name:             "Deneb bid with Electra head block - Not compatible",
+			bidVersion:       version.Deneb,
+			headBlockVersion: version.Electra,
+			want:             false,
+		},
+		{
+			name:             "Electra bid with Deneb head block - Not compatible",
+			bidVersion:       version.Electra,
+			headBlockVersion: version.Deneb,
+			want:             false,
+		},
+		{
+			name:             "Capella bid with Deneb head block - Not compatible",
+			bidVersion:       version.Capella,
+			headBlockVersion: version.Deneb,
+			want:             false,
+		},
+		{
+			name:             "Bellatrix bid with Capella head block - Not compatible",
+			bidVersion:       version.Bellatrix,
+			headBlockVersion: version.Capella,
+			want:             false,
+		},
+		{
+			name:             "Phase0 bid with Altair head block - Not compatible",
+			bidVersion:       version.Phase0,
+			headBlockVersion: version.Altair,
+			want:             false,
+		},
+		{
+			name:             "Deneb bid with Fulu head block - Not compatible",
+			bidVersion:       version.Deneb,
+			headBlockVersion: version.Fulu,
+			want:             false,
+		},
+		{
+			name:             "Capella bid with Fulu head block - Not compatible",
+			bidVersion:       version.Capella,
+			headBlockVersion: version.Fulu,
+			want:             false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := isVersionCompatible(tt.bidVersion, tt.headBlockVersion)
+			if got != tt.want {
+				t.Errorf("isVersionCompatible(%d, %d) = %v, want %v", tt.bidVersion, tt.headBlockVersion, got, tt.want)
+			}
+		})
+	}
+}

beacon-chain/rpc/testutil/mock_stater.go

@@ -15,14 +15,17 @@ type MockStater struct {
 	BeaconStateRoot   []byte
 	StatesBySlot      map[primitives.Slot]state.BeaconState
 	StatesByRoot      map[[32]byte]state.BeaconState
+	CustomError       error
 }
 
 // State --
 func (m *MockStater) State(ctx context.Context, id []byte) (state.BeaconState, error) {
+	if m.CustomError != nil {
+		return nil, m.CustomError
+	}
 	if m.StateProviderFunc != nil {
 		return m.StateProviderFunc(ctx, id)
 	}
-
 	if m.BeaconState != nil {
 		return m.BeaconState, nil
 	}

beacon-chain/state/stategen/getter.go

@@ -259,7 +259,7 @@ func (s *State) latestAncestor(ctx context.Context, blockRoot [32]byte) (state.B
 	defer span.End()
 
 	if s.isFinalizedRoot(blockRoot) {
-		finalizedState := s.finalizedState()
+		finalizedState := s.FinalizedState()
 		if finalizedState != nil {
 			return finalizedState, nil
 		}
@@ -297,7 +297,7 @@ func (s *State) latestAncestor(ctx context.Context, blockRoot [32]byte) (state.B
 
 		// Does the state exist in finalized info cache.
 		if s.isFinalizedRoot(parentRoot) {
-			return s.finalizedState(), nil
+			return s.FinalizedState(), nil
 		}
 
 		// Does the state exist in epoch boundary cache.

beacon-chain/state/stategen/service.go

@@ -196,7 +196,7 @@ func (s *State) isFinalizedRoot(r [32]byte) bool {
 }
 
 // Returns the cached and copied finalized state.
-func (s *State) finalizedState() state.BeaconState {
+func (s *State) FinalizedState() state.BeaconState {
 	s.finalizedInfo.lock.RLock()
 	defer s.finalizedInfo.lock.RUnlock()
 	return s.finalizedInfo.state.Copy()

beacon-chain/state/stategen/service_test.go

@@ -32,5 +32,5 @@ func TestResume(t *testing.T) {
 	require.DeepSSZEqual(t, beaconState.ToProtoUnsafe(), resumeState.ToProtoUnsafe())
 	assert.Equal(t, params.BeaconConfig().SlotsPerEpoch, service.finalizedInfo.slot, "Did not get watned slot")
 	assert.Equal(t, service.finalizedInfo.root, root, "Did not get wanted root")
-	assert.NotNil(t, service.finalizedState(), "Wanted a non nil finalized state")
+	assert.NotNil(t, service.FinalizedState(), "Wanted a non nil finalized state")
 }

beacon-chain/sync/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
         "block_batcher.go",
         "broadcast_bls_changes.go",
         "context.go",
+        "custody.go",
         "data_columns_reconstruct.go",
         "deadlines.go",
         "decode_pubsub.go",
@@ -166,6 +167,7 @@ go_test(
         "block_batcher_test.go",
         "broadcast_bls_changes_test.go",
         "context_test.go",
+        "custody_test.go",
         "data_columns_reconstruct_test.go",
         "decode_pubsub_test.go",
         "error_test.go",
@@ -212,6 +214,7 @@ go_test(
     shard_count = 4,
     deps = [
         "//async/abool:go_default_library",
+        "//async/event:go_default_library",
         "//beacon-chain/blockchain:go_default_library",
         "//beacon-chain/blockchain/kzg:go_default_library",
         "//beacon-chain/blockchain/testing:go_default_library",

beacon-chain/sync/custody.go

@@ -0,0 +1,130 @@
+package sync
+
+import (
+	"strings"
+	"time"
+
+	"github.com/OffchainLabs/prysm/v6/async"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
+	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+var nilFinalizedStateError = errors.New("finalized state is nil")
+
+func (s *Service) maintainCustodyInfo() {
+	const interval = 1 * time.Minute
+
+	async.RunEvery(s.ctx, interval, func() {
+		if err := s.updateCustodyInfoIfNeeded(); err != nil {
+			log.WithError(err).Error("Failed to update custody info")
+		}
+	})
+}
+
+func (s *Service) updateCustodyInfoIfNeeded() error {
+	const minimumPeerCount = 1
+
+	// Get our actual custody group count.
+	actualCustodyGrounpCount, err := s.cfg.p2p.CustodyGroupCount()
+	if err != nil {
+		return errors.Wrap(err, "p2p custody group count")
+	}
+
+	// Get our target custody group count.
+	targetCustodyGroupCount, err := s.custodyGroupCount()
+	if err != nil {
+		return errors.Wrap(err, "custody group count")
+	}
+
+	// If the actual custody group count is already equal to the target, skip the update.
+	if actualCustodyGrounpCount >= targetCustodyGroupCount {
+		return nil
+	}
+
+	// Check that all subscribed data column sidecars topics have at least `minimumPeerCount` peers.
+	topics := s.cfg.p2p.PubSub().GetTopics()
+	enoughPeers := true
+	for _, topic := range topics {
+		if !strings.Contains(topic, p2p.GossipDataColumnSidecarMessage) {
+			continue
+		}
+
+		if peers := s.cfg.p2p.PubSub().ListPeers(topic); len(peers) < minimumPeerCount {
+			// If a topic has fewer than the minimum required peers, log a warning.
+			log.WithFields(logrus.Fields{
+				"topic":            topic,
+				"peerCount":        len(peers),
+				"minimumPeerCount": minimumPeerCount,
+			}).Debug("Insufficient peers for data column sidecar topic to maintain custody count")
+			enoughPeers = false
+		}
+	}
+
+	if !enoughPeers {
+		return nil
+	}
+
+	headROBlock, err := s.cfg.chain.HeadBlock(s.ctx)
+	if err != nil {
+		return errors.Wrap(err, "head block")
+	}
+	headSlot := headROBlock.Block().Slot()
+
+	storedEarliestSlot, storedGroupCount, err := s.cfg.p2p.UpdateCustodyInfo(headSlot, targetCustodyGroupCount)
+	if err != nil {
+		return errors.Wrap(err, "p2p update custody info")
+	}
+
+	if _, _, err := s.cfg.beaconDB.UpdateCustodyInfo(s.ctx, storedEarliestSlot, storedGroupCount); err != nil {
+		return errors.Wrap(err, "beacon db update custody info")
+	}
+
+	return nil
+}
+
+// custodyGroupCount computes the custody group count based on the custody requirement,
+// the validators custody requirement, and whether the node is subscribed to all data subnets.
+func (s *Service) custodyGroupCount() (uint64, error) {
+	beaconConfig := params.BeaconConfig()
+
+	if flags.Get().SubscribeAllDataSubnets {
+		return beaconConfig.NumberOfCustodyGroups, nil
+	}
+
+	validatorsCustodyRequirement, err := s.validatorsCustodyRequirement()
+	if err != nil {
+		return 0, errors.Wrap(err, "validators custody requirement")
+	}
+
+	return max(beaconConfig.CustodyRequirement, validatorsCustodyRequirement), nil
+}
+
+// validatorsCustodyRequirements computes the custody requirements based on the
+// finalized state and the tracked validators.
+func (s *Service) validatorsCustodyRequirement() (uint64, error) {
+	// Get the indices of the tracked validators.
+	indices := s.trackedValidatorsCache.Indices()
+
+	// Return early if no validators are tracked.
+	if len(indices) == 0 {
+		return 0, nil
+	}
+
+	// Retrieve the finalized state.
+	finalizedState := s.cfg.stateGen.FinalizedState()
+	if finalizedState == nil || finalizedState.IsNil() {
+		return 0, nilFinalizedStateError
+	}
+
+	// Compute the validators custody requirements.
+	result, err := peerdas.ValidatorsCustodyRequirement(finalizedState, indices)
+	if err != nil {
+		return 0, errors.Wrap(err, "validators custody requirements")
+	}
+
+	return result, nil
+}

beacon-chain/sync/custody_test.go

@@ -0,0 +1,195 @@
+package sync
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	mock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
+	dbtesting "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
+	p2ptest "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
+	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	eth "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+type testSetup struct {
+	service     *Service
+	p2pService  *p2ptest.TestP2P
+	beaconDB    db.Database
+	ctx         context.Context
+	initialSlot primitives.Slot
+	initialCount uint64
+}
+
+func setupCustodyTest(t *testing.T, withChain bool) *testSetup {
+	ctx := t.Context()
+	p2pService := p2ptest.NewTestP2P(t)
+	beaconDB := dbtesting.SetupDB(t)
+	
+	const (
+		initialEarliestSlot = primitives.Slot(50)
+		initialCustodyCount = uint64(5)
+	)
+
+	_, _, err := p2pService.UpdateCustodyInfo(initialEarliestSlot, initialCustodyCount)
+	require.NoError(t, err)
+
+	dbEarliestAvailableSlot, dbCustodyCount, err := beaconDB.UpdateCustodyInfo(ctx, initialEarliestSlot, initialCustodyCount)
+	require.NoError(t, err)
+	require.Equal(t, initialEarliestSlot, dbEarliestAvailableSlot)
+	require.Equal(t, initialCustodyCount, dbCustodyCount)
+
+	cfg := &config{
+		p2p:      p2pService,
+		beaconDB: beaconDB,
+	}
+
+	if withChain {
+		const headSlot = primitives.Slot(100)
+		block, err := blocks.NewSignedBeaconBlock(&eth.SignedBeaconBlock{
+			Block: &eth.BeaconBlock{
+				Body: &eth.BeaconBlockBody{},
+				Slot: headSlot,
+			},
+		})
+		require.NoError(t, err)
+
+		cfg.chain = &mock.ChainService{
+			Genesis:          time.Now(),
+			ValidAttestation: true,
+			FinalizedCheckPoint: &ethpb.Checkpoint{
+				Epoch: 0,
+			},
+			Block: block,
+		}
+	}
+
+	service := &Service{
+		ctx:                    ctx,
+		cfg:                    cfg,
+		trackedValidatorsCache: cache.NewTrackedValidatorsCache(),
+	}
+
+	return &testSetup{
+		service:      service,
+		p2pService:   p2pService,
+		beaconDB:     beaconDB,
+		ctx:          ctx,
+		initialSlot:  initialEarliestSlot,
+		initialCount: initialCustodyCount,
+	}
+}
+
+func (ts *testSetup) assertCustodyInfo(t *testing.T, expectedSlot primitives.Slot, expectedCount uint64) {
+	p2pEarliestSlot, err := ts.p2pService.EarliestAvailableSlot()
+	require.NoError(t, err)
+	require.Equal(t, expectedSlot, p2pEarliestSlot)
+
+	p2pCustodyCount, err := ts.p2pService.CustodyGroupCount()
+	require.NoError(t, err)
+	require.Equal(t, expectedCount, p2pCustodyCount)
+
+	dbEarliestSlot, dbCustodyCount, err := ts.beaconDB.UpdateCustodyInfo(ts.ctx, 0, 0)
+	require.NoError(t, err)
+	require.Equal(t, expectedSlot, dbEarliestSlot)
+	require.Equal(t, expectedCount, dbCustodyCount)
+}
+
+func withSubscribeAllDataSubnets(t *testing.T, fn func()) {
+	originalFlag := flags.Get().SubscribeAllDataSubnets
+	defer func() {
+		flags.Get().SubscribeAllDataSubnets = originalFlag
+	}()
+	flags.Get().SubscribeAllDataSubnets = true
+	fn()
+}
+
+func TestUpdateCustodyInfoIfNeeded(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	beaconConfig := params.BeaconConfig()
+	beaconConfig.NumberOfCustodyGroups = 128
+	beaconConfig.CustodyRequirement = 4
+	beaconConfig.SamplesPerSlot = 8
+	params.OverrideBeaconConfig(beaconConfig)
+
+	t.Run("Skip update when actual custody count >= target", func(t *testing.T) {
+		setup := setupCustodyTest(t, false)
+		
+		err := setup.service.updateCustodyInfoIfNeeded()
+		require.NoError(t, err)
+
+		setup.assertCustodyInfo(t, setup.initialSlot, setup.initialCount)
+	})
+
+	t.Run("not enough peers in some subnets", func(t *testing.T) {
+		const randomTopic = "aTotalRandomTopicName"
+		require.Equal(t, false, strings.Contains(randomTopic, p2p.GossipDataColumnSidecarMessage))
+
+		withSubscribeAllDataSubnets(t, func() {
+			setup := setupCustodyTest(t, false)
+
+			_, err := setup.service.cfg.p2p.SubscribeToTopic(p2p.GossipDataColumnSidecarMessage)
+			require.NoError(t, err)
+
+			_, err = setup.service.cfg.p2p.SubscribeToTopic(randomTopic)
+			require.NoError(t, err)
+
+			err = setup.service.updateCustodyInfoIfNeeded()
+			require.NoError(t, err)
+
+			setup.assertCustodyInfo(t, setup.initialSlot, setup.initialCount)
+		})
+	})
+
+	t.Run("should update", func(t *testing.T) {
+		withSubscribeAllDataSubnets(t, func() {
+			setup := setupCustodyTest(t, true)
+
+			err := setup.service.updateCustodyInfoIfNeeded()
+			require.NoError(t, err)
+
+			const expectedSlot = primitives.Slot(100)
+			setup.assertCustodyInfo(t, expectedSlot, beaconConfig.NumberOfCustodyGroups)
+		})
+	})
+}
+
+func TestCustodyGroupCount(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	config := params.BeaconConfig()
+	config.NumberOfCustodyGroups = 10
+	config.CustodyRequirement = 3
+	params.OverrideBeaconConfig(config)
+
+	t.Run("SubscribeAllDataSubnets enabled returns NumberOfCustodyGroups", func(t *testing.T) {
+		withSubscribeAllDataSubnets(t, func() {
+			service := &Service{
+				ctx: context.Background(),
+			}
+
+			result, err := service.custodyGroupCount()
+			require.NoError(t, err)
+			require.Equal(t, config.NumberOfCustodyGroups, result)
+		})
+	})
+
+	t.Run("No tracked validators returns CustodyRequirement", func(t *testing.T) {
+		service := &Service{
+			ctx:                    context.Background(),
+			trackedValidatorsCache: cache.NewTrackedValidatorsCache(),
+		}
+
+		result, err := service.custodyGroupCount()
+		require.NoError(t, err)
+		require.Equal(t, config.CustodyRequirement, result)
+	})
+}

beacon-chain/sync/data_columns_reconstruct.go

@@ -32,6 +32,7 @@ func (s *Service) reconstructSaveBroadcastDataColumnSidecars(
 	root [fieldparams.RootLength]byte,
 ) error {
 	startTime := time.Now()
+	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
 
 	// Lock to prevent concurrent reconstructions.
 	s.reconstructionLock.Lock()
@@ -49,8 +50,13 @@ func (s *Service) reconstructSaveBroadcastDataColumnSidecars(
 
 	// Retrieve our local node info.
 	nodeID := s.cfg.p2p.NodeID()
-	custodyGroupCount := s.cfg.custodyInfo.ActualGroupCount()
-	localNodeInfo, _, err := peerdas.Info(nodeID, custodyGroupCount)
+	custodyGroupCount, err := s.cfg.p2p.CustodyGroupCount()
+	if err != nil {
+		return errors.Wrap(err, "custody group count")
+	}
+
+	samplingSize := max(custodyGroupCount, samplesPerSlot)
+	localNodeInfo, _, err := peerdas.Info(nodeID, samplingSize)
 	if err != nil {
 		return errors.Wrap(err, "peer info")
 	}
@@ -155,10 +161,12 @@ func (s *Service) broadcastMissingDataColumnSidecars(
 	// Get the node ID.
 	nodeID := s.cfg.p2p.NodeID()
 
-	// Get the custody group count.
-	custodyGroupCount := s.cfg.custodyInfo.ActualGroupCount()
-
 	// Retrieve the local node info.
+	custodyGroupCount, err := s.cfg.p2p.CustodyGroupCount()
+	if err != nil {
+		return errors.Wrap(err, "custody group count")
+	}
+
 	localNodeInfo, _, err := peerdas.Info(nodeID, custodyGroupCount)
 	if err != nil {
 		return errors.Wrap(err, "peerdas info")

beacon-chain/sync/data_columns_reconstruct_test.go

@@ -65,15 +65,10 @@ func TestReconstructDataColumns(t *testing.T) {
 		err := storage.Save(verifiedRoDataColumns[:minimumCount])
 		require.NoError(t, err)
 
-		custodyInfo := &peerdas.CustodyInfo{}
-		custodyInfo.TargetGroupCount.SetValidatorsCustodyRequirement(cgc)
-		custodyInfo.ToAdvertiseGroupCount.Set(cgc)
-
 		service := NewService(
 			ctx,
 			WithP2P(p2ptest.NewTestP2P(t)),
 			WithDataColumnStorage(storage),
-			WithCustodyInfo(custodyInfo),
 			WithChainService(&mockChain.ChainService{}),
 		)
 
@@ -121,14 +116,9 @@ func TestBroadcastMissingDataColumnSidecars(t *testing.T) {
 	slot, proposerIndex := block.Slot(), block.ProposerIndex()
 
 	t.Run("no missing sidecars", func(t *testing.T) {
-		custodyInfo := &peerdas.CustodyInfo{}
-		custodyInfo.TargetGroupCount.SetValidatorsCustodyRequirement(cgc)
-		custodyInfo.ToAdvertiseGroupCount.Set(cgc)
-
 		service := NewService(
 			ctx,
 			WithP2P(p2ptest.NewTestP2P(t)),
-			WithCustodyInfo(custodyInfo),
 		)
 
 		for _, index := range [...]uint64{1, 17, 19, 42, 75, 87, 102, 117} {
@@ -141,10 +131,6 @@ func TestBroadcastMissingDataColumnSidecars(t *testing.T) {
 	})
 
 	t.Run("some missing sidecars", func(t *testing.T) {
-		custodyInfo := &peerdas.CustodyInfo{}
-		custodyInfo.TargetGroupCount.SetValidatorsCustodyRequirement(cgc)
-		custodyInfo.ToAdvertiseGroupCount.Set(cgc)
-
 		toSave := make([]blocks.VerifiedRODataColumn, 0, 2)
 		for _, index := range [...]uint64{42, 87} {
 			toSave = append(toSave, verifiedRoDataColumns[index])
@@ -158,9 +144,10 @@ func TestBroadcastMissingDataColumnSidecars(t *testing.T) {
 		service := NewService(
 			ctx,
 			WithP2P(p2p),
-			WithCustodyInfo(custodyInfo),
 			WithDataColumnStorage(storage),
 		)
+		_, _, err = service.cfg.p2p.UpdateCustodyInfo(0, cgc)
+		require.NoError(t, err)
 
 		for _, index := range [...]uint64{1, 17, 19, 102, 117} { // 42, 75 and 87 are missing
 			key := computeCacheKey(slot, proposerIndex, index)
@@ -186,6 +173,5 @@ func TestBroadcastMissingDataColumnSidecars(t *testing.T) {
 		}
 
 		require.Equal(t, true, p2p.BroadcastCalled.Load())
-
 	})
 }

beacon-chain/sync/fork_watcher_test.go

@@ -7,7 +7,7 @@ import (
 
 	"github.com/OffchainLabs/prysm/v6/async/abool"
 	mockChain "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
 	p2ptest "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
@@ -47,7 +47,6 @@ func TestService_CheckForNextEpochFork(t *testing.T) {
 						chain:       chainService,
 						clock:       startup.NewClock(gt, vr),
 						initialSync: &mockSync.Sync{IsSyncing: false},
-						custodyInfo: &peerdas.CustodyInfo{},
 					},
 					chainStarted: abool.New(),
 					subHandler:   newSubTopicHandler(),
@@ -83,7 +82,6 @@ func TestService_CheckForNextEpochFork(t *testing.T) {
 						chain:       chainService,
 						clock:       startup.NewClock(gt, vr),
 						initialSync: &mockSync.Sync{IsSyncing: false},
-						custodyInfo: &peerdas.CustodyInfo{},
 					},
 					chainStarted: abool.New(),
 					subHandler:   newSubTopicHandler(),
@@ -128,7 +126,6 @@ func TestService_CheckForNextEpochFork(t *testing.T) {
 						chain:       chainService,
 						clock:       startup.NewClock(chainService.Genesis, chainService.ValidatorsRoot),
 						initialSync: &mockSync.Sync{IsSyncing: false},
-						custodyInfo: &peerdas.CustodyInfo{},
 					},
 					chainStarted: abool.New(),
 					subHandler:   newSubTopicHandler(),
@@ -171,7 +168,6 @@ func TestService_CheckForNextEpochFork(t *testing.T) {
 						chain:       chainService,
 						clock:       startup.NewClock(gt, vr),
 						initialSync: &mockSync.Sync{IsSyncing: false},
-						custodyInfo: &peerdas.CustodyInfo{},
 					},
 					chainStarted: abool.New(),
 					subHandler:   newSubTopicHandler(),
@@ -216,7 +212,6 @@ func TestService_CheckForNextEpochFork(t *testing.T) {
 						chain:       chainService,
 						clock:       startup.NewClock(gt, vr),
 						initialSync: &mockSync.Sync{IsSyncing: false},
-						custodyInfo: &peerdas.CustodyInfo{},
 					},
 					chainStarted: abool.New(),
 					subHandler:   newSubTopicHandler(),
@@ -261,10 +256,10 @@ func TestService_CheckForNextEpochFork(t *testing.T) {
 						chain:       chainService,
 						clock:       startup.NewClock(gt, vr),
 						initialSync: &mockSync.Sync{IsSyncing: false},
-						custodyInfo: &peerdas.CustodyInfo{},
 					},
-					chainStarted: abool.New(),
-					subHandler:   newSubTopicHandler(),
+					chainStarted:           abool.New(),
+					subHandler:             newSubTopicHandler(),
+					trackedValidatorsCache: cache.NewTrackedValidatorsCache(),
 				}
 				return r
 			},

beacon-chain/sync/initial-sync/blocks_fetcher_utils_test.go

@@ -387,7 +387,7 @@ func TestBlocksFetcher_findForkWithPeer(t *testing.T) {
 		defer func() {
 			assert.NoError(t, p1.Disconnect(p2.PeerID()))
 		}()
-		p1.Peers().SetChainState(p2.PeerID(), &ethpb.Status{
+		p1.Peers().SetChainState(p2.PeerID(), &ethpb.StatusV2{
 			HeadRoot: nil,
 			HeadSlot: 0,
 		})

beacon-chain/sync/initial-sync/initial_sync_test.go

@@ -232,7 +232,7 @@ func connectPeer(t *testing.T, host *p2pt.TestP2P, datum *peerData, peerStatus *
 
 	peerStatus.Add(new(enr.Record), p.PeerID(), nil, network.DirOutbound)
 	peerStatus.SetConnectionState(p.PeerID(), peers.Connected)
-	peerStatus.SetChainState(p.PeerID(), &ethpb.Status{
+	peerStatus.SetChainState(p.PeerID(), &ethpb.StatusV2{
 		ForkDigest:     params.BeaconConfig().GenesisForkVersion,
 		FinalizedRoot:  []byte(fmt.Sprintf("finalized_root %d", datum.finalizedEpoch)),
 		FinalizedEpoch: datum.finalizedEpoch,
@@ -331,7 +331,7 @@ func connectPeerHavingBlocks(
 
 	peerStatus.Add(new(enr.Record), p.PeerID(), nil, network.DirOutbound)
 	peerStatus.SetConnectionState(p.PeerID(), peers.Connected)
-	peerStatus.SetChainState(p.PeerID(), &ethpb.Status{
+	peerStatus.SetChainState(p.PeerID(), &ethpb.StatusV2{
 		ForkDigest:     params.BeaconConfig().GenesisForkVersion,
 		FinalizedRoot:  []byte(fmt.Sprintf("finalized_root %d", finalizedEpoch)),
 		FinalizedEpoch: finalizedEpoch,

beacon-chain/sync/options.go

@@ -7,7 +7,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/operation"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution"
@@ -199,10 +198,10 @@ func WithAvailableBlocker(avb coverage.AvailableBlocker) Option {
 	}
 }
 
-// WithCustodyInfo for custody info.
-func WithCustodyInfo(custodyInfo *peerdas.CustodyInfo) Option {
+// WithTrackedValidatorsCache for tracked validators cache.
+func WithTrackedValidatorsCache(c *cache.TrackedValidatorsCache) Option {
 	return func(s *Service) error {
-		s.cfg.custodyInfo = custodyInfo
+		s.trackedValidatorsCache = c
 		return nil
 	}
 }

beacon-chain/sync/pending_attestations_queue_test.go

@@ -51,7 +51,7 @@ func TestProcessPendingAtts_NoBlockRequestBlock(t *testing.T) {
 	assert.Equal(t, 1, len(p1.BHost.Network().Peers()), "Expected peers to be connected")
 	p1.Peers().Add(new(enr.Record), p2.PeerID(), nil, network.DirOutbound)
 	p1.Peers().SetConnectionState(p2.PeerID(), peers.Connected)
-	p1.Peers().SetChainState(p2.PeerID(), &ethpb.Status{})
+	p1.Peers().SetChainState(p2.PeerID(), &ethpb.StatusV2{})
 
 	chain := &mock.ChainService{Genesis: prysmTime.Now(), FinalizedCheckPoint: &ethpb.Checkpoint{}}
 	r := &Service{

beacon-chain/sync/pending_blocks_queue_test.go

@@ -406,7 +406,7 @@ func TestRegularSyncBeaconBlockSubscriber_ProcessPendingBlocks_2Chains(t *testin
 
 	p1.Peers().Add(new(enr.Record), p2.PeerID(), nil, network.DirOutbound)
 	p1.Peers().SetConnectionState(p2.PeerID(), peers.Connected)
-	p1.Peers().SetChainState(p2.PeerID(), &ethpb.Status{})
+	p1.Peers().SetChainState(p2.PeerID(), &ethpb.StatusV2{})
 
 	b0 := util.NewBeaconBlock()
 	util.SaveBlock(t, t.Context(), r.cfg.beaconDB, b0)
@@ -505,7 +505,7 @@ func TestRegularSyncBeaconBlockSubscriber_PruneOldPendingBlocks(t *testing.T) {
 
 	p1.Peers().Add(new(enr.Record), p1.PeerID(), nil, network.DirOutbound)
 	p1.Peers().SetConnectionState(p1.PeerID(), peers.Connected)
-	p1.Peers().SetChainState(p1.PeerID(), &ethpb.Status{})
+	p1.Peers().SetChainState(p1.PeerID(), &ethpb.StatusV2{})
 
 	b0 := util.NewBeaconBlock()
 	util.SaveBlock(t, t.Context(), r.cfg.beaconDB, b0)
@@ -611,7 +611,7 @@ func TestService_BatchRootRequest(t *testing.T) {
 
 	p1.Peers().Add(new(enr.Record), p2.PeerID(), nil, network.DirOutbound)
 	p1.Peers().SetConnectionState(p2.PeerID(), peers.Connected)
-	p1.Peers().SetChainState(p2.PeerID(), &ethpb.Status{FinalizedEpoch: 2})
+	p1.Peers().SetChainState(p2.PeerID(), &ethpb.StatusV2{FinalizedEpoch: 2})
 
 	b0 := util.NewBeaconBlock()
 	util.SaveBlock(t, t.Context(), r.cfg.beaconDB, b0)

beacon-chain/sync/rate_limiter.go

@@ -64,6 +64,7 @@ func newRateLimiter(p2pProvider p2p.P2P) *limiter {
 	topicMap[addEncoding(p2p.RPCPingTopicV1)] = leakybucket.NewCollector(1, defaultBurstLimit, leakyBucketPeriod, false /* deleteEmptyBuckets */)
 	// Status Message
 	topicMap[addEncoding(p2p.RPCStatusTopicV1)] = leakybucket.NewCollector(1, defaultBurstLimit, leakyBucketPeriod, false /* deleteEmptyBuckets */)
+	topicMap[addEncoding(p2p.RPCStatusTopicV2)] = leakybucket.NewCollector(1, defaultBurstLimit, leakyBucketPeriod, false /* deleteEmptyBuckets */)
 
 	// Use a single collector for block requests
 	blockCollector := leakybucket.NewCollector(allowedBlocksPerSecond, allowedBlocksBurst, blockBucketPeriod, false /* deleteEmptyBuckets */)

beacon-chain/sync/rate_limiter_test.go

@@ -17,7 +17,7 @@ import (
 
 func TestNewRateLimiter(t *testing.T) {
 	rlimiter := newRateLimiter(mockp2p.NewTestP2P(t))
-	assert.Equal(t, len(rlimiter.limiterMap), 19, "correct number of topics not registered")
+	assert.Equal(t, len(rlimiter.limiterMap), 20, "correct number of topics not registered")
 }
 
 func TestNewRateLimiter_FreeCorrectly(t *testing.T) {

beacon-chain/sync/rpc.go

@@ -43,13 +43,14 @@ func (s *Service) rpcHandlerByTopicFromFork(forkIndex int) (map[string]rpcHandle
 	// Fulu: https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#messages
 	if forkIndex >= version.Fulu {
 		return map[string]rpcHandler{
+			p2p.RPCStatusTopicV2:                    s.statusRPCHandler, // Updated in Fulu
 			p2p.RPCGoodByeTopicV1:                   s.goodbyeRPCHandler,
 			p2p.RPCBlocksByRangeTopicV2:             s.beaconBlocksByRangeRPCHandler,
 			p2p.RPCBlocksByRootTopicV2:              s.beaconBlocksRootRPCHandler,
 			p2p.RPCPingTopicV1:                      s.pingHandler,
-			p2p.RPCMetaDataTopicV3:                  s.metaDataHandler, // Modified in Fulu
-			p2p.RPCBlobSidecarsByRootTopicV1:        s.blobSidecarByRootRPCHandler,
-			p2p.RPCBlobSidecarsByRangeTopicV1:       s.blobSidecarsByRangeRPCHandler,
+			p2p.RPCMetaDataTopicV3:                  s.metaDataHandler,                     // Updated in Fulu
+			p2p.RPCBlobSidecarsByRootTopicV1:        s.blobSidecarByRootRPCHandler,         // Modified in Fulu
+			p2p.RPCBlobSidecarsByRangeTopicV1:       s.blobSidecarsByRangeRPCHandler,       // Modified in Fulu
 			p2p.RPCDataColumnSidecarsByRootTopicV1:  s.dataColumnSidecarByRootRPCHandler,   // Added in Fulu
 			p2p.RPCDataColumnSidecarsByRangeTopicV1: s.dataColumnSidecarsByRangeRPCHandler, // Added in Fulu
 		}, nil
@@ -60,8 +61,8 @@ func (s *Service) rpcHandlerByTopicFromFork(forkIndex int) (map[string]rpcHandle
 		return map[string]rpcHandler{
 			p2p.RPCStatusTopicV1:              s.statusRPCHandler,
 			p2p.RPCGoodByeTopicV1:             s.goodbyeRPCHandler,
-			p2p.RPCBlocksByRangeTopicV2:       s.beaconBlocksByRangeRPCHandler,
-			p2p.RPCBlocksByRootTopicV2:        s.beaconBlocksRootRPCHandler,
+			p2p.RPCBlocksByRangeTopicV2:       s.beaconBlocksByRangeRPCHandler, // Modified in Electra
+			p2p.RPCBlocksByRootTopicV2:        s.beaconBlocksRootRPCHandler,    // Modified in Electra
 			p2p.RPCPingTopicV1:                s.pingHandler,
 			p2p.RPCMetaDataTopicV2:            s.metaDataHandler,
 			p2p.RPCBlobSidecarsByRootTopicV1:  s.blobSidecarByRootRPCHandler,   // Modified in Electra
@@ -90,8 +91,8 @@ func (s *Service) rpcHandlerByTopicFromFork(forkIndex int) (map[string]rpcHandle
 		handler := map[string]rpcHandler{
 			p2p.RPCStatusTopicV1:        s.statusRPCHandler,
 			p2p.RPCGoodByeTopicV1:       s.goodbyeRPCHandler,
-			p2p.RPCBlocksByRangeTopicV2: s.beaconBlocksByRangeRPCHandler, // Updated in Altair and modified in Capella
-			p2p.RPCBlocksByRootTopicV2:  s.beaconBlocksRootRPCHandler,    // Updated in Altair and modified in Capella
+			p2p.RPCBlocksByRangeTopicV2: s.beaconBlocksByRangeRPCHandler, // Updated in Altair and modified in Bellatrix and Capella
+			p2p.RPCBlocksByRootTopicV2:  s.beaconBlocksRootRPCHandler,    // Updated in Altair and modified in Bellatrix and Capella
 			p2p.RPCPingTopicV1:          s.pingHandler,
 			p2p.RPCMetaDataTopicV2:      s.metaDataHandler, // Updated in Altair
 		}

beacon-chain/sync/rpc_beacon_blocks_by_root_test.go

@@ -394,7 +394,7 @@ func TestRequestPendingBlobs(t *testing.T) {
 		}
 		p1.Peers().Add(new(enr.Record), p2.PeerID(), nil, network.DirOutbound)
 		p1.Peers().SetConnectionState(p2.PeerID(), peers.Connected)
-		p1.Peers().SetChainState(p2.PeerID(), &ethpb.Status{FinalizedEpoch: 1})
+		p1.Peers().SetChainState(p2.PeerID(), &ethpb.StatusV2{FinalizedEpoch: 1})
 		s := &Service{
 			cfg: &config{
 				p2p:         p1,

beacon-chain/sync/rpc_light_client_test.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/OffchainLabs/prysm/v6/async/abool"
+	"github.com/OffchainLabs/prysm/v6/async/event"
 	mockChain "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
 	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	db "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
@@ -54,7 +55,7 @@ func TestRPC_LightClientBootstrap(t *testing.T) {
 			stateNotifier: &mockChain.MockStateNotifier{},
 		},
 		chainStarted: abool.New(),
-		lcStore:      lightClient.NewLightClientStore(d),
+		lcStore:      lightClient.NewLightClientStore(d, &p2ptest.FakeP2P{}, new(event.Feed)),
 		subHandler:   newSubTopicHandler(),
 		rateLimiter:  newRateLimiter(p1),
 	}
@@ -176,7 +177,7 @@ func TestRPC_LightClientOptimisticUpdate(t *testing.T) {
 			stateNotifier: &mockChain.MockStateNotifier{},
 		},
 		chainStarted: abool.New(),
-		lcStore:      &lightClient.Store{},
+		lcStore:      lightClient.NewLightClientStore(d, &p2ptest.FakeP2P{}, new(event.Feed)),
 		subHandler:   newSubTopicHandler(),
 		rateLimiter:  newRateLimiter(p1),
 	}
@@ -202,7 +203,7 @@ func TestRPC_LightClientOptimisticUpdate(t *testing.T) {
 			update, err := lightClient.NewLightClientOptimisticUpdateFromBeaconState(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock)
 			require.NoError(t, err)
 
-			r.lcStore.SetLastOptimisticUpdate(update)
+			r.lcStore.SetLastOptimisticUpdate(update, false)
 
 			var wg sync.WaitGroup
 			wg.Add(1)
@@ -296,7 +297,7 @@ func TestRPC_LightClientFinalityUpdate(t *testing.T) {
 			stateNotifier: &mockChain.MockStateNotifier{},
 		},
 		chainStarted: abool.New(),
-		lcStore:      &lightClient.Store{},
+		lcStore:      lightClient.NewLightClientStore(d, &p2ptest.FakeP2P{}, new(event.Feed)),
 		subHandler:   newSubTopicHandler(),
 		rateLimiter:  newRateLimiter(p1),
 	}
@@ -322,7 +323,7 @@ func TestRPC_LightClientFinalityUpdate(t *testing.T) {
 			update, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
 			require.NoError(t, err)
 
-			r.lcStore.SetLastFinalityUpdate(update)
+			r.lcStore.SetLastFinalityUpdate(update, false)
 
 			var wg sync.WaitGroup
 			wg.Add(1)
@@ -416,7 +417,7 @@ func TestRPC_LightClientUpdatesByRange(t *testing.T) {
 			stateNotifier: &mockChain.MockStateNotifier{},
 		},
 		chainStarted: abool.New(),
-		lcStore:      lightClient.NewLightClientStore(d),
+		lcStore:      lightClient.NewLightClientStore(d, &p2ptest.FakeP2P{}, new(event.Feed)),
 		subHandler:   newSubTopicHandler(),
 		rateLimiter:  newRateLimiter(p1),
 	}

beacon-chain/sync/rpc_status.go

@@ -10,6 +10,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/async"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
 	p2ptypes "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
 	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v6/config/params"
@@ -22,6 +23,7 @@ import (
 	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/pkg/errors"
+	ssz "github.com/prysmaticlabs/fastssz"
 	"github.com/sirupsen/logrus"
 )
 
@@ -136,7 +138,7 @@ func (s *Service) sendRPCStatusRequest(ctx context.Context, peer peer.ID) error
 
 	headRoot, err := s.cfg.chain.HeadRoot(ctx)
 	if err != nil {
-		return errors.Wrap(err, "head root")
+		return errors.Wrap(err, "chain head root")
 	}
 
 	forkDigest, err := s.currentForkDigest()
@@ -144,26 +146,24 @@ func (s *Service) sendRPCStatusRequest(ctx context.Context, peer peer.ID) error
 		return errors.Wrap(err, "current fork digest")
 	}
 
-	cp := s.cfg.chain.FinalizedCheckpt()
-	resp := &pb.Status{
-		ForkDigest:     forkDigest[:],
-		FinalizedRoot:  cp.Root,
-		FinalizedEpoch: cp.Epoch,
-		HeadRoot:       headRoot,
-		HeadSlot:       s.cfg.chain.HeadSlot(),
-	}
+	// Compute the current epoch.
+	currentSlot := s.cfg.clock.CurrentSlot()
+	currentEpoch := slots.ToEpoch(currentSlot)
 
-	log := log.WithField("peer", peer)
-
-	topic, err := p2p.TopicFromMessage(p2p.StatusMessageName, slots.ToEpoch(s.cfg.clock.CurrentSlot()))
+	// Compute the topic for the status request regarding the current epoch.
+	topic, err := p2p.TopicFromMessage(p2p.StatusMessageName, currentEpoch)
 	if err != nil {
 		return errors.Wrap(err, "topic from message")
 	}
 
-	stream, err := s.cfg.p2p.Send(ctx, resp, topic, peer)
+	cp := s.cfg.chain.FinalizedCheckpt()
+	status := s.buildStatusFromEpoch(currentEpoch, forkDigest, cp.Root, cp.Epoch, headRoot)
+
+	stream, err := s.cfg.p2p.Send(ctx, status, topic, peer)
 	if err != nil {
-		return errors.Wrap(err, "send p2p message")
+		return errors.Wrap(err, "p2p send")
 	}
+
 	defer closeStream(stream, log)
 
 	code, errMsg, err := ReadStatusCode(stream, s.cfg.p2p.Encoding())
@@ -171,16 +171,14 @@ func (s *Service) sendRPCStatusRequest(ctx context.Context, peer peer.ID) error
 		s.downscorePeer(peer, "statusRequestReadStatusCodeError")
 		return errors.Wrap(err, "read status code")
 	}
-
 	if code != 0 {
 		s.downscorePeer(peer, "statusRequestNonNullStatusCode")
 		return errors.New(errMsg)
 	}
 
-	msg := &pb.Status{}
-	if err := s.cfg.p2p.Encoding().DecodeWithMaxLength(stream, msg); err != nil {
-		s.downscorePeer(peer, "statusRequestDecodeError")
-		return errors.Wrap(err, "decode status message")
+	msg, err := s.decodeStatus(stream, currentEpoch)
+	if err != nil {
+		return errors.Wrap(err, "decode status")
 	}
 
 	// If validation fails, validation error is logged, and peer status scorer will mark peer as bad.
@@ -189,9 +187,35 @@ func (s *Service) sendRPCStatusRequest(ctx context.Context, peer peer.ID) error
 	if err := s.cfg.p2p.Peers().IsBad(peer); err != nil {
 		s.disconnectBadPeer(s.ctx, peer, err)
 	}
+
 	return err
 }
 
+func (s *Service) decodeStatus(stream network.Stream, epoch primitives.Epoch) (*pb.StatusV2, error) {
+	if epoch >= params.BeaconConfig().FuluForkEpoch {
+		msg := new(pb.StatusV2)
+		if err := s.cfg.p2p.Encoding().DecodeWithMaxLength(stream, msg); err != nil {
+			s.cfg.p2p.Peers().Scorers().BadResponsesScorer().Increment(stream.Conn().RemotePeer())
+			return nil, errors.Wrap(err, "decode with max length")
+		}
+
+		return msg, nil
+	}
+
+	msg := new(pb.Status)
+	if err := s.cfg.p2p.Encoding().DecodeWithMaxLength(stream, msg); err != nil {
+		s.cfg.p2p.Peers().Scorers().BadResponsesScorer().Increment(stream.Conn().RemotePeer())
+		return nil, errors.Wrap(err, "decode with max length")
+	}
+
+	status, err := statusV2(msg)
+	if err != nil {
+		return nil, errors.Wrap(err, "status data")
+	}
+
+	return status, nil
+}
+
 func (s *Service) reValidatePeer(ctx context.Context, id peer.ID) error {
 	s.cfg.p2p.Peers().Scorers().PeerStatusScorer().SetHeadSlot(s.cfg.chain.HeadSlot())
 	if err := s.sendRPCStatusRequest(ctx, id); err != nil {
@@ -211,10 +235,11 @@ func (s *Service) statusRPCHandler(ctx context.Context, msg interface{}, stream
 	defer cancel()
 	SetRPCStreamDeadlines(stream)
 	log := log.WithField("handler", "status")
-	m, ok := msg.(*pb.Status)
-	if !ok {
-		return errors.New("message is not type *pb.Status")
+	m, err := statusV2(msg)
+	if err != nil {
+		return errors.Wrap(err, "status data")
 	}
+
 	if err := s.rateLimiter.validateRequest(stream, 1); err != nil {
 		return err
 	}
@@ -275,30 +300,123 @@ func (s *Service) statusRPCHandler(ctx context.Context, msg interface{}, stream
 func (s *Service) respondWithStatus(ctx context.Context, stream network.Stream) error {
 	headRoot, err := s.cfg.chain.HeadRoot(ctx)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "chain head root")
 	}
 
 	forkDigest, err := s.currentForkDigest()
 	if err != nil {
-		return err
+		return errors.Wrap(err, "current fork digest")
 	}
+
 	cp := s.cfg.chain.FinalizedCheckpt()
-	resp := &pb.Status{
-		ForkDigest:     forkDigest[:],
-		FinalizedRoot:  cp.Root,
-		FinalizedEpoch: cp.Epoch,
-		HeadRoot:       headRoot,
-		HeadSlot:       s.cfg.chain.HeadSlot(),
+	status, err := s.buildStatusFromStream(stream, forkDigest, cp.Root, cp.Epoch, headRoot)
+	if err != nil {
+		return errors.Wrap(err, "build status")
 	}
 
 	if _, err := stream.Write([]byte{responseCodeSuccess}); err != nil && !isUnwantedError(err) {
 		log.WithError(err).Debug("Could not write to stream")
 	}
-	_, err = s.cfg.p2p.Encoding().EncodeWithMaxLength(stream, resp)
-	return err
+
+	if _, err := s.cfg.p2p.Encoding().EncodeWithMaxLength(stream, status); err != nil {
+		return errors.Wrap(err, "encode with max length")
+	}
+
+	return nil
 }
 
-func (s *Service) validateStatusMessage(ctx context.Context, msg *pb.Status) error {
+func (s *Service) buildStatusFromStream(
+	stream libp2pcore.Stream,
+	forkDigest [4]byte,
+	finalizedRoot []byte,
+	FinalizedEpoch primitives.Epoch,
+	headRoot []byte,
+) (ssz.Marshaler, error) {
+	// Get the stream version from the protocol.
+	_, _, streamVersion, err := p2p.TopicDeconstructor(string(stream.Protocol()))
+	if err != nil {
+		err := errors.Wrap(err, "topic deconstructor")
+
+		resp, err2 := s.generateErrorResponse(responseCodeServerError, types.ErrGeneric.Error())
+		if err2 != nil {
+			log.WithError(err2).Debug("Could not write to stream")
+			return nil, err
+		}
+
+		if _, err2 := stream.Write(resp); err2 != nil {
+			log.WithError(err2).Debug("Could not write to stream")
+		}
+
+		return nil, err
+	}
+
+	if streamVersion == p2p.SchemaVersionV2 {
+		earliestAvailableSlot, err := s.cfg.p2p.EarliestAvailableSlot()
+		if err != nil {
+			return nil, errors.Wrap(err, "earliest available slot")
+		}
+
+		status := &pb.StatusV2{
+			ForkDigest:            forkDigest[:],
+			FinalizedRoot:         finalizedRoot,
+			FinalizedEpoch:        FinalizedEpoch,
+			HeadRoot:              headRoot,
+			HeadSlot:              s.cfg.chain.HeadSlot(),
+			EarliestAvailableSlot: earliestAvailableSlot,
+		}
+
+		return status, nil
+	}
+
+	status := &pb.Status{
+		ForkDigest:     forkDigest[:],
+		FinalizedRoot:  finalizedRoot,
+		FinalizedEpoch: FinalizedEpoch,
+		HeadRoot:       headRoot,
+		HeadSlot:       s.cfg.chain.HeadSlot(),
+	}
+
+	return status, nil
+}
+
+func (s *Service) buildStatusFromEpoch(
+	epoch primitives.Epoch,
+	forkDigest [4]byte,
+	finalizedRoot []byte,
+	FinalizedEpoch primitives.Epoch,
+	headRoot []byte,
+) ssz.Marshaler {
+	// Get the stream version from the protocol.
+	if epoch >= params.BeaconConfig().FuluForkEpoch {
+		status := &pb.StatusV2{
+			ForkDigest:            forkDigest[:],
+			FinalizedRoot:         finalizedRoot,
+			FinalizedEpoch:        FinalizedEpoch,
+			HeadRoot:              headRoot,
+			HeadSlot:              s.cfg.chain.HeadSlot(),
+			EarliestAvailableSlot: 0,
+		}
+
+		return status
+	}
+
+	status := &pb.Status{
+		ForkDigest:     forkDigest[:],
+		FinalizedRoot:  finalizedRoot,
+		FinalizedEpoch: FinalizedEpoch,
+		HeadRoot:       headRoot,
+		HeadSlot:       s.cfg.chain.HeadSlot(),
+	}
+
+	return status
+}
+
+func (s *Service) validateStatusMessage(ctx context.Context, genericMsg interface{}) error {
+	msg, err := statusV2(genericMsg)
+	if err != nil {
+		return errors.Wrap(err, "status data")
+	}
+
 	forkDigest, err := s.currentForkDigest()
 	if err != nil {
 		return err
@@ -368,3 +486,24 @@ func (s *Service) validateStatusMessage(ctx context.Context, msg *pb.Status) err
 	}
 	return p2ptypes.ErrInvalidEpoch
 }
+
+func statusV2(msg interface{}) (*pb.StatusV2, error) {
+	if status, ok := msg.(*pb.StatusV2); ok {
+		return status, nil
+	}
+
+	if status, ok := msg.(*pb.Status); ok {
+		status := &pb.StatusV2{
+			ForkDigest:            status.ForkDigest,
+			FinalizedRoot:         status.FinalizedRoot,
+			FinalizedEpoch:        status.FinalizedEpoch,
+			HeadRoot:              status.HeadRoot,
+			HeadSlot:              status.HeadSlot,
+			EarliestAvailableSlot: 0, // Default value for StatusV2
+		}
+
+		return status, nil
+	}
+
+	return nil, errors.New("message is not type *pb.Status or *pb.StatusV2")
+}

beacon-chain/sync/rpc_status_test.go

@@ -6,6 +6,8 @@ import (
 	"testing"
 	"time"
 
+	beaconState "github.com/OffchainLabs/prysm/v6/beacon-chain/state"
+
 	"github.com/OffchainLabs/prysm/v6/async/abool"
 	mock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
@@ -399,6 +401,7 @@ func TestHandshakeHandlers_Roundtrip(t *testing.T) {
 	if util.WaitTimeout(&wg, 1*time.Second) {
 		t.Fatal("Did not receive stream within 1 sec")
 	}
+
 	if util.WaitTimeout(&wg2, 1*time.Second) {
 		t.Fatal("Did not receive stream within 1 sec")
 	}
@@ -425,80 +428,148 @@ func TestHandshakeHandlers_Roundtrip(t *testing.T) {
 }
 
 func TestStatusRPCRequest_RequestSent(t *testing.T) {
-	p1 := p2ptest.NewTestP2P(t)
-	p2 := p2ptest.NewTestP2P(t)
+	beaconConfig := params.BeaconConfig()
 
-	// Set up a head state with data we expect.
-	head := util.NewBeaconBlock()
-	head.Block.Slot = 111
-	headRoot, err := head.Block.HashTreeRoot()
-	require.NoError(t, err)
-	finalized := util.NewBeaconBlock()
-	finalized.Block.Slot = 40
-	finalizedRoot, err := finalized.Block.HashTreeRoot()
-	require.NoError(t, err)
-	genesisState, err := transition.GenesisBeaconState(t.Context(), nil, 0, &ethpb.Eth1Data{})
-	require.NoError(t, err)
-	require.NoError(t, genesisState.SetSlot(111))
-	require.NoError(t, genesisState.UpdateBlockRootAtIndex(111%uint64(params.BeaconConfig().SlotsPerHistoricalRoot), headRoot))
-	finalizedCheckpt := &ethpb.Checkpoint{
-		Epoch: 5,
-		Root:  finalizedRoot[:],
-	}
+	testCases := []struct {
+		name          string
+		fuluForkEpoch primitives.Epoch
+		topic         string
+		streamHandler func(service *Service, stream network.Stream, genesisState beaconState.BeaconState, beaconRoot, headRoot, finalizedRoot []byte)
+	}{
+		{
+			name:          "before fulu",
+			fuluForkEpoch: beaconConfig.FarFutureEpoch,
+			topic:         "/eth2/beacon_chain/req/status/1/ssz_snappy",
+			streamHandler: func(service *Service, stream network.Stream, genesisState beaconState.BeaconState, beaconRoot, headRoot, finalizedRoot []byte) {
+				out := &ethpb.Status{}
+				require.NoError(t, service.cfg.p2p.Encoding().DecodeWithMaxLength(stream, out))
 
-	chain := &mock.ChainService{
-		State:               genesisState,
-		FinalizedCheckPoint: finalizedCheckpt,
-		Root:                headRoot[:],
-		Fork: &ethpb.Fork{
-			PreviousVersion: params.BeaconConfig().GenesisForkVersion,
-			CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
+				digest, err := service.currentForkDigest()
+				require.NoError(t, err)
+
+				expected := &ethpb.Status{
+					ForkDigest:     digest[:],
+					HeadSlot:       genesisState.Slot(),
+					HeadRoot:       headRoot,
+					FinalizedEpoch: 5,
+					FinalizedRoot:  finalizedRoot,
+				}
+
+				if !proto.Equal(out, expected) {
+					t.Errorf("Did not receive expected message. Got %+v wanted %+v", out, expected)
+				}
+
+				err = service.respondWithStatus(context.Background(), stream)
+				require.NoError(t, err)
+			},
 		},
-		Genesis:        time.Now(),
-		ValidatorsRoot: [32]byte{'A'},
-	}
-	r := &Service{
-		cfg: &config{
-			p2p:   p1,
-			chain: chain,
-			clock: startup.NewClock(chain.Genesis, chain.ValidatorsRoot),
+		{
+			name:          "after fulu",
+			fuluForkEpoch: 0,
+			topic:         "/eth2/beacon_chain/req/status/2/ssz_snappy",
+			streamHandler: func(service *Service, stream network.Stream, genesisState beaconState.BeaconState, beaconRoot, headRoot, finalizedRoot []byte) {
+				out := &ethpb.StatusV2{}
+				assert.NoError(t, service.cfg.p2p.Encoding().DecodeWithMaxLength(stream, out))
+
+				digest, err := service.currentForkDigest()
+				assert.NoError(t, err)
+
+				expected := &ethpb.StatusV2{
+					ForkDigest:            digest[:],
+					HeadSlot:              genesisState.Slot(),
+					HeadRoot:              headRoot,
+					FinalizedEpoch:        5,
+					FinalizedRoot:         finalizedRoot,
+					EarliestAvailableSlot: 0,
+				}
+
+				if !proto.Equal(out, expected) {
+					t.Errorf("Did not receive expected message. Got %+v wanted %+v", out, expected)
+				}
+
+				err = service.respondWithStatus(t.Context(), stream)
+				require.NoError(t, err)
+			},
 		},
-		ctx:         t.Context(),
-		rateLimiter: newRateLimiter(p1),
 	}
 
-	// Setup streams
-	pcl := protocol.ID("/eth2/beacon_chain/req/status/1/ssz_snappy")
-	topic := string(pcl)
-	r.rateLimiter.limiterMap[topic] = leakybucket.NewCollector(1, 1, time.Second, false)
-	var wg sync.WaitGroup
-	wg.Add(1)
-	p2.BHost.SetStreamHandler(pcl, func(stream network.Stream) {
-		defer wg.Done()
-		out := &ethpb.Status{}
-		assert.NoError(t, r.cfg.p2p.Encoding().DecodeWithMaxLength(stream, out))
-		digest, err := r.currentForkDigest()
-		assert.NoError(t, err)
-		expected := &ethpb.Status{
-			ForkDigest:     digest[:],
-			HeadSlot:       genesisState.Slot(),
-			HeadRoot:       headRoot[:],
-			FinalizedEpoch: 5,
-			FinalizedRoot:  finalizedRoot[:],
-		}
-		if !proto.Equal(out, expected) {
-			t.Errorf("Did not receive expected message. Got %+v wanted %+v", out, expected)
-		}
-	})
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			params.SetupTestConfigCleanup(t)
+			cfg := params.BeaconConfig().Copy()
+			cfg.FuluForkEpoch = tc.fuluForkEpoch
+			cfg.ForkVersionSchedule[bytesutil.ToBytes4(cfg.FuluForkVersion)] = cfg.FuluForkEpoch
+			params.OverrideBeaconConfig(cfg)
 
-	p1.AddConnectionHandler(r.sendRPCStatusRequest, nil)
-	p1.Connect(p2)
+			p1, p2 := p2ptest.NewTestP2P(t), p2ptest.NewTestP2P(t)
+			p1.Connect(p2)
 
-	if util.WaitTimeout(&wg, 1*time.Second) {
-		t.Fatal("Did not receive stream within 1 sec")
+			// Set up a head state with data we expect.
+			head := util.NewBeaconBlock()
+			head.Block.Slot = 111
+			headRoot, err := head.Block.HashTreeRoot()
+			require.NoError(t, err)
+
+			finalized := util.NewBeaconBlock()
+			finalized.Block.Slot = 40
+			finalizedRoot, err := finalized.Block.HashTreeRoot()
+			require.NoError(t, err)
+
+			genesisState, err := transition.GenesisBeaconState(context.Background(), nil, 0, &ethpb.Eth1Data{})
+			require.NoError(t, err)
+
+			require.NoError(t, genesisState.SetSlot(111))
+			require.NoError(t, genesisState.UpdateBlockRootAtIndex(111%uint64(params.BeaconConfig().SlotsPerHistoricalRoot), headRoot))
+
+			finalizedCheckpt := &ethpb.Checkpoint{
+				Epoch: 5,
+				Root:  finalizedRoot[:],
+			}
+
+			chain := &mock.ChainService{
+				State:               genesisState,
+				FinalizedCheckPoint: finalizedCheckpt,
+				Root:                headRoot[:],
+				Fork: &ethpb.Fork{
+					PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+					CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
+				},
+				Genesis:        time.Now(),
+				ValidatorsRoot: [32]byte{'A'},
+			}
+
+			r := &Service{
+				cfg: &config{
+					p2p:   p1,
+					chain: chain,
+					clock: startup.NewClock(chain.Genesis, chain.ValidatorsRoot),
+				},
+				ctx:         context.Background(),
+				rateLimiter: newRateLimiter(p1),
+			}
+
+			// Setup streams
+			pcl := protocol.ID(tc.topic)
+
+			r.rateLimiter.limiterMap[tc.topic] = leakybucket.NewCollector(1, 1, time.Second, false)
+
+			var wg sync.WaitGroup
+			wg.Add(1)
+			p2.BHost.SetStreamHandler(pcl, func(stream network.Stream) {
+				defer wg.Done()
+				tc.streamHandler(r, stream, genesisState, chain.Root, headRoot[:], finalizedRoot[:])
+			})
+
+			err = r.sendRPCStatusRequest(context.Background(), p2.BHost.ID())
+			require.ErrorIs(t, err, p2ptypes.ErrInvalidEpoch)
+
+			if util.WaitTimeout(&wg, 1*time.Hour) {
+				t.Fatal("Did not receive stream within 1 sec")
+			}
+
+			assert.Equal(t, 1, len(p1.BHost.Network().Peers()), "Expected peers to continue being connected")
+		})
 	}
-
-	assert.Equal(t, 1, len(p1.BHost.Network().Peers()), "Expected peers to continue being connected")
 }
 
 func TestStatusRPCRequest_FinalizedBlockExists(t *testing.T) {