prysm-pulse/beacon-chain/blockchain/receive_attestation.go
2019-10-04 14:54:21 -07:00

113 lines
3.9 KiB
Go

package blockchain
import (
"bytes"
"context"
"encoding/hex"
"fmt"
"github.com/pkg/errors"
"github.com/prysmaticlabs/go-ssz"
"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
"github.com/prysmaticlabs/prysm/shared/bytesutil"
"github.com/sirupsen/logrus"
"go.opencensus.io/trace"
)
// AttestationReceiver interface defines the methods of chain service receive and processing new attestations.
type AttestationReceiver interface {
ReceiveAttestation(ctx context.Context, att *ethpb.Attestation) error
ReceiveAttestationNoPubsub(ctx context.Context, att *ethpb.Attestation) error
}
// ReceiveAttestation is a function that defines the operations that are preformed on
// attestation that is received from regular sync. The operations consist of:
// 1. Gossip attestation to other peers
// 2. Validate attestation, update validator's latest vote
// 3. Apply fork choice to the processed attestation
// 4. Save latest head info
func (s *Service) ReceiveAttestation(ctx context.Context, att *ethpb.Attestation) error {
ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.ReceiveAttestation")
defer span.End()
// Broadcast the new attestation to the network.
if err := s.p2p.Broadcast(ctx, att); err != nil {
return errors.Wrap(err, "could not broadcast attestation")
}
attDataRoot, err := ssz.HashTreeRoot(att.Data)
if err != nil {
log.WithError(err).Error("Failed to hash attestation")
}
log.WithFields(logrus.Fields{
"attRoot": fmt.Sprintf("%#x", attDataRoot),
"blockRoot": fmt.Sprintf("%#x", att.Data.BeaconBlockRoot),
}).Debug("Broadcasting attestation")
if err := s.ReceiveAttestationNoPubsub(ctx, att); err != nil {
return err
}
processedAtt.Inc()
return nil
}
// ReceiveAttestationNoPubsub is a function that defines the operations that are preformed on
// attestation that is received from regular sync. The operations consist of:
// 1. Validate attestation, update validator's latest vote
// 2. Apply fork choice to the processed attestation
// 3. Save latest head info
func (s *Service) ReceiveAttestationNoPubsub(ctx context.Context, att *ethpb.Attestation) error {
ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.ReceiveAttestationNoPubsub")
defer span.End()
// Update forkchoice store for the new attestation
attSlot, err := s.forkChoiceStore.OnAttestation(ctx, att)
if err != nil {
return errors.Wrap(err, "could not process attestation from fork choice service")
}
// Run fork choice for head block after updating fork choice store.
headRoot, err := s.forkChoiceStore.Head(ctx)
if err != nil {
return errors.Wrap(err, "could not get head from fork choice service")
}
// Only save head if it's different than the current head.
if !bytes.Equal(headRoot, s.HeadRoot()) {
headBlk, err := s.beaconDB.Block(ctx, bytesutil.ToBytes32(headRoot))
if err != nil {
return errors.Wrap(err, "could not compute state from block head")
}
if err := s.saveHead(ctx, headBlk, bytesutil.ToBytes32(headRoot)); err != nil {
return errors.Wrap(err, "could not save head")
}
}
// Skip checking for competing attestation's target roots at epoch boundary.
if !helpers.IsEpochStart(attSlot) {
s.headLock.RLock()
defer s.headLock.RUnlock()
targetRoot, err := helpers.BlockRoot(s.headState, att.Data.Target.Epoch)
if err != nil {
return errors.Wrapf(err, "could not get target root for epoch %d", att.Data.Target.Epoch)
}
isCompetingAtts(targetRoot, att.Data.Target.Root[:])
}
processedAttNoPubsub.Inc()
return nil
}
// This checks if the attestation is from a competing chain, emits warning and updates metrics.
func isCompetingAtts(headTargetRoot []byte, attTargetRoot []byte) {
if !bytes.Equal(attTargetRoot, headTargetRoot) {
log.WithFields(logrus.Fields{
"attTargetRoot": hex.EncodeToString(attTargetRoot),
"headTargetRoot": hex.EncodeToString(headTargetRoot),
}).Warn("target heads different from new attestation")
competingAtts.Inc()
}
}