Files
prysm/beacon-chain/p2p/broadcaster.go
2026-01-05 12:31:59 +05:30

606 lines
22 KiB
Go

package p2p
import (
"bytes"
"context"
"fmt"
"reflect"
"slices"
"sync"
"time"
"github.com/OffchainLabs/prysm/v7/beacon-chain/core/altair"
"github.com/OffchainLabs/prysm/v7/beacon-chain/core/helpers"
"github.com/OffchainLabs/prysm/v7/beacon-chain/core/peerdas"
fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
"github.com/OffchainLabs/prysm/v7/config/params"
"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
"github.com/OffchainLabs/prysm/v7/consensus-types/interfaces"
"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
"github.com/OffchainLabs/prysm/v7/crypto/hash"
"github.com/OffchainLabs/prysm/v7/monitoring/tracing"
"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
"github.com/OffchainLabs/prysm/v7/time/slots"
pubsub "github.com/libp2p/go-libp2p-pubsub"
"github.com/pkg/errors"
ssz "github.com/prysmaticlabs/fastssz"
"github.com/sirupsen/logrus"
"google.golang.org/protobuf/proto"
)
const minimumPeersPerSubnetForBroadcast = 1
// ErrMessageNotMapped occurs on a Broadcast attempt when a message has not been defined in the
// GossipTypeMapping.
var ErrMessageNotMapped = errors.New("message type is not mapped to a PubSub topic")
// Broadcast a message to the p2p network, the message is assumed to be
// broadcasted to the current fork.
func (s *Service) Broadcast(ctx context.Context, msg proto.Message) error {
ctx, span := trace.StartSpan(ctx, "p2p.Broadcast")
defer span.End()
twoSlots := time.Duration(2*params.BeaconConfig().SecondsPerSlot) * time.Second
ctx, cancel := context.WithTimeout(ctx, twoSlots)
defer cancel()
forkDigest, err := s.currentForkDigest()
if err != nil {
err := errors.Wrap(err, "could not retrieve fork digest")
tracing.AnnotateError(span, err)
return err
}
topic, ok := GossipTypeMapping[reflect.TypeOf(msg)]
if !ok {
tracing.AnnotateError(span, ErrMessageNotMapped)
return ErrMessageNotMapped
}
castMsg, ok := msg.(ssz.Marshaler)
if !ok {
return errors.Errorf("message of %T does not support marshaller interface", msg)
}
return s.broadcastObject(ctx, castMsg, fmt.Sprintf(topic, forkDigest))
}
// BroadcastAttestation broadcasts an attestation to the p2p network, the message is assumed to be
// broadcasted to the current fork.
func (s *Service) BroadcastAttestation(ctx context.Context, subnet uint64, att ethpb.Att) error {
if att == nil {
return errors.New("attempted to broadcast nil attestation")
}
ctx, span := trace.StartSpan(ctx, "p2p.BroadcastAttestation")
defer span.End()
forkDigest, err := s.currentForkDigest()
if err != nil {
err := errors.Wrap(err, "could not retrieve fork digest")
tracing.AnnotateError(span, err)
return err
}
// Non-blocking broadcast, with attempts to discover a subnet peer if none available.
go s.internalBroadcastAttestation(ctx, subnet, att, forkDigest)
return nil
}
// BroadcastSyncCommitteeMessage broadcasts a sync committee message to the p2p network, the message is assumed to be
// broadcasted to the current fork.
func (s *Service) BroadcastSyncCommitteeMessage(ctx context.Context, subnet uint64, sMsg *ethpb.SyncCommitteeMessage) error {
if sMsg == nil {
return errors.New("attempted to broadcast nil sync committee message")
}
ctx, span := trace.StartSpan(ctx, "p2p.BroadcastSyncCommitteeMessage")
defer span.End()
forkDigest, err := s.currentForkDigest()
if err != nil {
err := errors.Wrap(err, "could not retrieve fork digest")
tracing.AnnotateError(span, err)
return err
}
// Non-blocking broadcast, with attempts to discover a subnet peer if none available.
go s.broadcastSyncCommittee(ctx, subnet, sMsg, forkDigest)
return nil
}
func (s *Service) internalBroadcastAttestation(ctx context.Context, subnet uint64, att ethpb.Att, forkDigest [fieldparams.VersionLength]byte) {
_, span := trace.StartSpan(ctx, "p2p.internalBroadcastAttestation")
defer span.End()
ctx = trace.NewContext(context.Background(), span) // clear parent context / deadline.
oneEpoch := time.Duration(1*params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().SecondsPerSlot)) * time.Second
ctx, cancel := context.WithTimeout(ctx, oneEpoch)
defer cancel()
// Ensure we have peers with this subnet.
s.subnetLocker(subnet).RLock()
hasPeer := s.hasPeerWithSubnet(attestationToTopic(subnet, forkDigest))
s.subnetLocker(subnet).RUnlock()
span.SetAttributes(
trace.BoolAttribute("hasPeer", hasPeer),
trace.Int64Attribute("slot", int64(att.GetData().Slot)), // lint:ignore uintcast -- It's safe to do this for tracing.
trace.Int64Attribute("subnet", int64(subnet)), // lint:ignore uintcast -- It's safe to do this for tracing.
)
if !hasPeer {
attestationBroadcastAttempts.Inc()
if err := func() error {
s.subnetLocker(subnet).Lock()
defer s.subnetLocker(subnet).Unlock()
if err := s.FindAndDialPeersWithSubnets(ctx, AttestationSubnetTopicFormat, forkDigest, minimumPeersPerSubnetForBroadcast, map[uint64]bool{subnet: true}); err != nil {
return errors.Wrap(err, "find peers with subnets")
}
savedAttestationBroadcasts.Inc()
return nil
}(); err != nil {
log.WithError(err).Error("Failed to find peers")
tracing.AnnotateError(span, err)
}
}
// In the event our attestation is outdated and beyond the
// acceptable threshold, we exit early and do not broadcast it.
currSlot := slots.CurrentSlot(s.genesisTime)
if err := helpers.ValidateAttestationTime(att.GetData().Slot, s.genesisTime, params.BeaconConfig().MaximumGossipClockDisparityDuration()); err != nil {
log.WithFields(logrus.Fields{
"attestationSlot": att.GetData().Slot,
"currentSlot": currSlot,
}).WithError(err).Debug("Attestation is too old to broadcast, discarding it")
return
}
if err := s.broadcastObject(ctx, att, attestationToTopic(subnet, forkDigest)); err != nil {
log.WithError(err).Error("Failed to broadcast attestation")
tracing.AnnotateError(span, err)
}
}
func (s *Service) broadcastSyncCommittee(ctx context.Context, subnet uint64, sMsg *ethpb.SyncCommitteeMessage, forkDigest [fieldparams.VersionLength]byte) {
_, span := trace.StartSpan(ctx, "p2p.broadcastSyncCommittee")
defer span.End()
ctx = trace.NewContext(context.Background(), span) // clear parent context / deadline.
oneSlot := time.Duration(1*params.BeaconConfig().SecondsPerSlot) * time.Second
ctx, cancel := context.WithTimeout(ctx, oneSlot)
defer cancel()
// Ensure we have peers with this subnet.
// This adds in a special value to the subnet
// to ensure that we can reuse the same subnet locker.
wrappedSubIdx := subnet + syncLockerVal
s.subnetLocker(wrappedSubIdx).RLock()
hasPeer := s.hasPeerWithSubnet(syncCommitteeToTopic(subnet, forkDigest))
s.subnetLocker(wrappedSubIdx).RUnlock()
span.SetAttributes(
trace.BoolAttribute("hasPeer", hasPeer),
trace.Int64Attribute("slot", int64(sMsg.Slot)), // lint:ignore uintcast -- It's safe to do this for tracing.
trace.Int64Attribute("subnet", int64(subnet)), // lint:ignore uintcast -- It's safe to do this for tracing.
)
if !hasPeer {
syncCommitteeBroadcastAttempts.Inc()
if err := func() error {
s.subnetLocker(wrappedSubIdx).Lock()
defer s.subnetLocker(wrappedSubIdx).Unlock()
if err := s.FindAndDialPeersWithSubnets(ctx, SyncCommitteeSubnetTopicFormat, forkDigest, minimumPeersPerSubnetForBroadcast, map[uint64]bool{subnet: true}); err != nil {
return errors.Wrap(err, "find peers with subnets")
}
savedSyncCommitteeBroadcasts.Inc()
return nil
}(); err != nil {
log.WithError(err).Error("Failed to find peers")
tracing.AnnotateError(span, err)
}
}
// In the event our sync message is outdated and beyond the
// acceptable threshold, we exit early and do not broadcast it.
if err := altair.ValidateSyncMessageTime(sMsg.Slot, s.genesisTime, params.BeaconConfig().MaximumGossipClockDisparityDuration()); err != nil {
log.WithError(err).Warn("Sync Committee Message is too old to broadcast, discarding it")
return
}
if err := s.broadcastObject(ctx, sMsg, syncCommitteeToTopic(subnet, forkDigest)); err != nil {
log.WithError(err).Error("Failed to broadcast sync committee message")
tracing.AnnotateError(span, err)
}
}
// BroadcastBlob broadcasts a blob to the p2p network, the message is assumed to be
// broadcasted to the current fork and to the input subnet.
func (s *Service) BroadcastBlob(ctx context.Context, subnet uint64, blob *ethpb.BlobSidecar) error {
ctx, span := trace.StartSpan(ctx, "p2p.BroadcastBlob")
defer span.End()
if blob == nil {
return errors.New("attempted to broadcast nil blob sidecar")
}
forkDigest, err := s.currentForkDigest()
if err != nil {
err := errors.Wrap(err, "could not retrieve fork digest")
tracing.AnnotateError(span, err)
return err
}
// Non-blocking broadcast, with attempts to discover a subnet peer if none available.
go s.internalBroadcastBlob(ctx, subnet, blob, forkDigest)
return nil
}
func (s *Service) internalBroadcastBlob(ctx context.Context, subnet uint64, blobSidecar *ethpb.BlobSidecar, forkDigest [fieldparams.VersionLength]byte) {
_, span := trace.StartSpan(ctx, "p2p.internalBroadcastBlob")
defer span.End()
ctx = trace.NewContext(context.Background(), span) // clear parent context / deadline.
oneSlot := time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second
ctx, cancel := context.WithTimeout(ctx, oneSlot)
defer cancel()
wrappedSubIdx := subnet + blobSubnetLockerVal
s.subnetLocker(wrappedSubIdx).RLock()
hasPeer := s.hasPeerWithSubnet(blobSubnetToTopic(subnet, forkDigest))
s.subnetLocker(wrappedSubIdx).RUnlock()
if !hasPeer {
blobSidecarBroadcastAttempts.Inc()
if err := func() error {
s.subnetLocker(wrappedSubIdx).Lock()
defer s.subnetLocker(wrappedSubIdx).Unlock()
if err := s.FindAndDialPeersWithSubnets(ctx, BlobSubnetTopicFormat, forkDigest, minimumPeersPerSubnetForBroadcast, map[uint64]bool{subnet: true}); err != nil {
return errors.Wrap(err, "find peers with subnets")
}
blobSidecarBroadcasts.Inc()
return nil
}(); err != nil {
log.WithError(err).Error("Failed to find peers")
tracing.AnnotateError(span, err)
}
}
if err := s.broadcastObject(ctx, blobSidecar, blobSubnetToTopic(subnet, forkDigest)); err != nil {
log.WithError(err).Error("Failed to broadcast blob sidecar")
tracing.AnnotateError(span, err)
}
}
func (s *Service) BroadcastLightClientOptimisticUpdate(ctx context.Context, update interfaces.LightClientOptimisticUpdate) error {
ctx, span := trace.StartSpan(ctx, "p2p.BroadcastLightClientOptimisticUpdate")
defer span.End()
if update == nil || update.IsNil() {
return errors.New("attempted to broadcast nil light client optimistic update")
}
// add delay to ensure block has time to propagate
slotStart, err := slots.StartTime(s.genesisTime, update.SignatureSlot())
if err != nil {
err := errors.Wrap(err, "could not compute slot start time")
tracing.AnnotateError(span, err)
return err
}
timeSinceSlotStart := time.Since(slotStart)
expectedDelay := params.BeaconConfig().SlotComponentDuration(params.BeaconConfig().SyncMessageDueBPS)
if timeSinceSlotStart < expectedDelay {
waitDuration := expectedDelay - timeSinceSlotStart
<-time.After(waitDuration)
}
digest := params.ForkDigest(slots.ToEpoch(update.AttestedHeader().Beacon().Slot))
if err := s.broadcastObject(ctx, update, lcOptimisticToTopic(digest)); err != nil {
log.WithError(err).Debug("Failed to broadcast light client optimistic update")
err := errors.Wrap(err, "could not publish message")
tracing.AnnotateError(span, err)
return err
}
log.Debug("Successfully broadcast light client optimistic update")
return nil
}
func (s *Service) BroadcastLightClientFinalityUpdate(ctx context.Context, update interfaces.LightClientFinalityUpdate) error {
ctx, span := trace.StartSpan(ctx, "p2p.BroadcastLightClientFinalityUpdate")
defer span.End()
if update == nil || update.IsNil() {
return errors.New("attempted to broadcast nil light client finality update")
}
// add delay to ensure block has time to propagate
slotStart, err := slots.StartTime(s.genesisTime, update.SignatureSlot())
if err != nil {
err := errors.Wrap(err, "could not compute slot start time")
tracing.AnnotateError(span, err)
return err
}
timeSinceSlotStart := time.Since(slotStart)
expectedDelay := params.BeaconConfig().SlotComponentDuration(params.BeaconConfig().SyncMessageDueBPS)
if timeSinceSlotStart < expectedDelay {
waitDuration := expectedDelay - timeSinceSlotStart
<-time.After(waitDuration)
}
forkDigest := params.ForkDigest(slots.ToEpoch(update.AttestedHeader().Beacon().Slot))
if err := s.broadcastObject(ctx, update, lcFinalityToTopic(forkDigest)); err != nil {
log.WithError(err).Debug("Failed to broadcast light client finality update")
err := errors.Wrap(err, "could not publish message")
tracing.AnnotateError(span, err)
return err
}
log.Debug("Successfully broadcast light client finality update")
return nil
}
// BroadcastDataColumnSidecars broadcasts multiple data column sidecars to the p2p network, after ensuring
// there is at least one peer in each needed subnet. If not, it will attempt to find one before broadcasting.
// This function is non-blocking. It stops trying to broadcast a given sidecar when more than one slot has passed, or the context is
// cancelled (whichever comes first).
func (s *Service) BroadcastDataColumnSidecars(ctx context.Context, sidecars []blocks.VerifiedRODataColumn) error {
// Increase the number of broadcast attempts.
dataColumnSidecarBroadcastAttempts.Add(float64(len(sidecars)))
// Retrieve the current fork digest.
forkDigest, err := s.currentForkDigest()
if err != nil {
return errors.Wrap(err, "current fork digest")
}
go s.broadcastDataColumnSidecars(ctx, forkDigest, sidecars)
return nil
}
// broadcastDataColumnSidecars broadcasts multiple data column sidecars to the p2p network, after ensuring
// there is at least one peer in each needed subnet. If not, it will attempt to find one before broadcasting.
// It returns when all broadcasts are complete, or the context is cancelled (whichever comes first).
func (s *Service) broadcastDataColumnSidecars(ctx context.Context, forkDigest [fieldparams.VersionLength]byte, sidecars []blocks.VerifiedRODataColumn) {
type rootAndIndex struct {
root [fieldparams.RootLength]byte
index uint64
}
var (
wg sync.WaitGroup
timings sync.Map
)
logLevel := logrus.GetLevel()
slotPerRoot := make(map[[fieldparams.RootLength]byte]primitives.Slot, 1)
var messageBatch pubsub.MessageBatch
for _, sidecar := range sidecars {
slotPerRoot[sidecar.BlockRoot()] = sidecar.Slot()
wg.Go(func() {
// Add tracing to the function.
_, span := trace.StartSpan(ctx, "p2p.broadcastDataColumnSidecars")
ctx = trace.NewContext(s.ctx, span) // clear parent context / deadline.
defer span.End()
// Compute the subnet for this data column sidecar.
subnet := peerdas.ComputeSubnetForDataColumnSidecar(sidecar.Index)
// Build the topic corresponding to subnet column subnet and this fork digest.
topic := dataColumnSubnetToTopic(subnet, forkDigest)
// Compute the wrapped subnet index.
wrappedSubIdx := subnet + dataColumnSubnetVal
// Find peers if needed.
if err := s.findPeersIfNeeded(ctx, wrappedSubIdx, DataColumnSubnetTopicFormat, forkDigest, subnet); err != nil {
tracing.AnnotateError(span, err)
log.WithError(err).Error("Cannot find peers if needed")
return
}
// Broadcast the data column sidecar to the network.
if err := s.batchObject(ctx, &messageBatch, sidecar, topic); err != nil {
tracing.AnnotateError(span, err)
log.WithError(err).Error("Cannot broadcast data column sidecar")
return
}
// Increase the number of successful broadcasts.
dataColumnSidecarBroadcasts.Inc()
// Record the timing for log purposes.
if logLevel >= logrus.DebugLevel {
root := sidecar.BlockRoot()
timings.Store(rootAndIndex{root: root, index: sidecar.Index}, time.Now())
}
})
}
// Wait for all messages to be added to the batch.
wg.Wait()
if err := s.pubsub.PublishBatch(&messageBatch); err != nil {
log.WithError(err).Error("Cannot publish batch for data column sidecars")
return
}
// The rest of this function is only for debug logging purposes.
if logLevel < logrus.DebugLevel {
return
}
type logInfo struct {
durationMin time.Duration
durationMax time.Duration
indices []uint64
}
logInfoPerRoot := make(map[[fieldparams.RootLength]byte]*logInfo, 1)
timings.Range(func(key any, value any) bool {
rootAndIndex, ok := key.(rootAndIndex)
if !ok {
log.Error("Could not cast key to rootAndIndex")
return true
}
broadcastTime, ok := value.(time.Time)
if !ok {
log.Error("Could not cast value to time.Time")
return true
}
slot, ok := slotPerRoot[rootAndIndex.root]
if !ok {
log.WithField("root", fmt.Sprintf("%#x", rootAndIndex.root)).Error("Could not find slot for root")
return true
}
duration, err := slots.SinceSlotStart(slot, s.genesisTime, broadcastTime)
if err != nil {
log.WithError(err).Error("Could not compute duration since slot start")
return true
}
info, ok := logInfoPerRoot[rootAndIndex.root]
if !ok {
logInfoPerRoot[rootAndIndex.root] = &logInfo{durationMin: duration, durationMax: duration, indices: []uint64{rootAndIndex.index}}
return true
}
info.durationMin = min(info.durationMin, duration)
info.durationMax = max(info.durationMax, duration)
info.indices = append(info.indices, rootAndIndex.index)
return true
})
for root, info := range logInfoPerRoot {
slices.Sort(info.indices)
log.WithFields(logrus.Fields{
"root": fmt.Sprintf("%#x", root),
"slot": slotPerRoot[root],
"count": len(info.indices),
"indices": helpers.PrettySlice(info.indices),
"timeSinceSlotStartMin": info.durationMin,
"timeSinceSlotStartMax": info.durationMax,
}).Debug("Broadcasted data column sidecars")
}
}
func (s *Service) findPeersIfNeeded(
ctx context.Context,
wrappedSubIdx uint64,
topicFormat string,
forkDigest [fieldparams.VersionLength]byte,
subnet uint64,
) error {
// Sending a data column sidecar to only one peer is not ideal,
// but it ensures at least one peer receives it.
s.subnetLocker(wrappedSubIdx).Lock()
defer s.subnetLocker(wrappedSubIdx).Unlock()
// No peers found, attempt to find peers with this subnet.
if err := s.FindAndDialPeersWithSubnets(ctx, topicFormat, forkDigest, minimumPeersPerSubnetForBroadcast, map[uint64]bool{subnet: true}); err != nil {
return errors.Wrap(err, "find peers with subnet")
}
return nil
}
// encodeGossipMessage encodes an object for gossip transmission.
// It returns the encoded bytes and the full topic with protocol suffix.
func (s *Service) encodeGossipMessage(obj ssz.Marshaler, topic string) ([]byte, string, error) {
buf := new(bytes.Buffer)
if _, err := s.Encoding().EncodeGossip(buf, obj); err != nil {
return nil, "", fmt.Errorf("could not encode message: %w", err)
}
return buf.Bytes(), topic + s.Encoding().ProtocolSuffix(), nil
}
// broadcastObject broadcasts a message to other peers in our gossip mesh.
func (s *Service) broadcastObject(ctx context.Context, obj ssz.Marshaler, topic string) error {
ctx, span := trace.StartSpan(ctx, "p2p.broadcastObject")
defer span.End()
span.SetAttributes(trace.StringAttribute("topic", topic))
data, fullTopic, err := s.encodeGossipMessage(obj, topic)
if err != nil {
tracing.AnnotateError(span, err)
return err
}
if span.IsRecording() {
id := hash.FastSum64(data)
messageLen := int64(len(data))
// lint:ignore uintcast -- It's safe to do this for tracing.
iid := int64(id)
span = trace.AddMessageSendEvent(span, iid, messageLen /*uncompressed*/, messageLen /*compressed*/)
}
if err := s.PublishToTopic(ctx, fullTopic, data); err != nil {
err := errors.Wrap(err, "could not publish message")
tracing.AnnotateError(span, err)
return err
}
return nil
}
// batchObject adds an object to a message batch for a future broadcast.
// The caller MUST publish the batch after all messages have been added.
func (s *Service) batchObject(ctx context.Context, batch *pubsub.MessageBatch, obj ssz.Marshaler, topic string) error {
ctx, span := trace.StartSpan(ctx, "p2p.batchObject")
defer span.End()
span.SetAttributes(trace.StringAttribute("topic", topic))
data, fullTopic, err := s.encodeGossipMessage(obj, topic)
if err != nil {
tracing.AnnotateError(span, err)
return err
}
if span.IsRecording() {
id := hash.FastSum64(data)
messageLen := int64(len(data))
// lint:ignore uintcast -- It's safe to do this for tracing.
iid := int64(id)
span = trace.AddMessageSendEvent(span, iid, messageLen /*uncompressed*/, messageLen /*compressed*/)
}
if err := s.addToBatch(ctx, batch, fullTopic, data); err != nil {
err := errors.Wrap(err, "could not publish message")
tracing.AnnotateError(span, err)
return err
}
return nil
}
func attestationToTopic(subnet uint64, forkDigest [fieldparams.VersionLength]byte) string {
return fmt.Sprintf(AttestationSubnetTopicFormat, forkDigest, subnet)
}
func syncCommitteeToTopic(subnet uint64, forkDigest [fieldparams.VersionLength]byte) string {
return fmt.Sprintf(SyncCommitteeSubnetTopicFormat, forkDigest, subnet)
}
func blobSubnetToTopic(subnet uint64, forkDigest [fieldparams.VersionLength]byte) string {
return fmt.Sprintf(BlobSubnetTopicFormat, forkDigest, subnet)
}
func lcOptimisticToTopic(forkDigest [4]byte) string {
return fmt.Sprintf(LightClientOptimisticUpdateTopicFormat, forkDigest)
}
func lcFinalityToTopic(forkDigest [4]byte) string {
return fmt.Sprintf(LightClientFinalityUpdateTopicFormat, forkDigest)
}
func dataColumnSubnetToTopic(subnet uint64, forkDigest [fieldparams.VersionLength]byte) string {
return fmt.Sprintf(DataColumnSubnetTopicFormat, forkDigest, subnet)
}