/
attester.go
242 lines (214 loc) · 8.78 KB
/
attester.go
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package validator
import (
"context"
"errors"
"fmt"
"github.com/prysmaticlabs/prysm/v3/beacon-chain/cache"
"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/feed"
"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/feed/operation"
"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/time"
"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/transition"
"github.com/prysmaticlabs/prysm/v3/config/params"
"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
"github.com/prysmaticlabs/prysm/v3/crypto/bls"
"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
"github.com/prysmaticlabs/prysm/v3/time/slots"
"go.opencensus.io/trace"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
"google.golang.org/protobuf/types/known/emptypb"
)
// GetAttestationData requests that the beacon node produce an attestation data object,
// which the validator acting as an attester will then sign.
func (vs *Server) GetAttestationData(ctx context.Context, req *ethpb.AttestationDataRequest) (*ethpb.AttestationData, error) {
ctx, span := trace.StartSpan(ctx, "AttesterServer.RequestAttestation")
defer span.End()
span.AddAttributes(
trace.Int64Attribute("slot", int64(req.Slot)),
trace.Int64Attribute("committeeIndex", int64(req.CommitteeIndex)),
)
if vs.SyncChecker.Syncing() {
return nil, status.Errorf(codes.Unavailable, "Syncing to latest head, not ready to respond")
}
// An optimistic validator MUST NOT participate in attestation. (i.e., sign across the DOMAIN_BEACON_ATTESTER, DOMAIN_SELECTION_PROOF or DOMAIN_AGGREGATE_AND_PROOF domains).
if err := vs.optimisticStatus(ctx); err != nil {
return nil, err
}
if err := helpers.ValidateAttestationTime(req.Slot, vs.TimeFetcher.GenesisTime(),
params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
return nil, status.Error(codes.InvalidArgument, fmt.Sprintf("invalid request: %v", err))
}
res, err := vs.AttestationCache.Get(ctx, req)
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not retrieve data from attestation cache: %v", err)
}
if res != nil {
res.CommitteeIndex = req.CommitteeIndex
return res, nil
}
if err := vs.AttestationCache.MarkInProgress(req); err != nil {
if errors.Is(err, cache.ErrAlreadyInProgress) {
res, err := vs.AttestationCache.Get(ctx, req)
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not retrieve data from attestation cache: %v", err)
}
if res == nil {
return nil, status.Error(codes.DataLoss, "A request was in progress and resolved to nil")
}
res.CommitteeIndex = req.CommitteeIndex
return res, nil
}
return nil, status.Errorf(codes.Internal, "Could not mark attestation as in-progress: %v", err)
}
defer func() {
if err := vs.AttestationCache.MarkNotInProgress(req); err != nil {
log.WithError(err).Error("Could not mark cache not in progress")
}
}()
headState, err := vs.HeadFetcher.HeadState(ctx)
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not retrieve head state: %v", err)
}
headRoot, err := vs.HeadFetcher.HeadRoot(ctx)
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not retrieve head root: %v", err)
}
// In the case that we receive an attestation request after a newer state/block has been processed.
if headState.Slot() > req.Slot {
headRoot, err = helpers.BlockRootAtSlot(headState, req.Slot)
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not get historical head root: %v", err)
}
headState, err = vs.StateGen.StateByRoot(ctx, bytesutil.ToBytes32(headRoot))
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not get historical head state: %v", err)
}
}
if headState == nil || headState.IsNil() {
return nil, status.Error(codes.Internal, "Could not lookup parent state from head.")
}
if time.CurrentEpoch(headState) < slots.ToEpoch(req.Slot) {
headState, err = transition.ProcessSlotsUsingNextSlotCache(ctx, headState, headRoot, req.Slot)
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not process slots up to %d: %v", req.Slot, err)
}
}
targetEpoch := time.CurrentEpoch(headState)
epochStartSlot, err := slots.EpochStart(targetEpoch)
if err != nil {
return nil, err
}
var targetRoot []byte
if epochStartSlot == headState.Slot() {
targetRoot = headRoot
} else {
targetRoot, err = helpers.BlockRootAtSlot(headState, epochStartSlot)
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not get target block for slot %d: %v", epochStartSlot, err)
}
if bytesutil.ToBytes32(targetRoot) == params.BeaconConfig().ZeroHash {
targetRoot = headRoot
}
}
res = ðpb.AttestationData{
Slot: req.Slot,
CommitteeIndex: req.CommitteeIndex,
BeaconBlockRoot: headRoot,
Source: headState.CurrentJustifiedCheckpoint(),
Target: ðpb.Checkpoint{
Epoch: targetEpoch,
Root: targetRoot,
},
}
if err := vs.AttestationCache.Put(ctx, req, res); err != nil {
return nil, status.Errorf(codes.Internal, "Could not store attestation data in cache: %v", err)
}
return res, nil
}
// ProposeAttestation is a function called by an attester to vote
// on a block via an attestation object as defined in the Ethereum Serenity specification.
func (vs *Server) ProposeAttestation(ctx context.Context, att *ethpb.Attestation) (*ethpb.AttestResponse, error) {
ctx, span := trace.StartSpan(ctx, "AttesterServer.ProposeAttestation")
defer span.End()
if _, err := bls.SignatureFromBytes(att.Signature); err != nil {
return nil, status.Error(codes.InvalidArgument, "Incorrect attestation signature")
}
root, err := att.Data.HashTreeRoot()
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not tree hash attestation: %v", err)
}
// Broadcast the unaggregated attestation on a feed to notify other services in the beacon node
// of a received unaggregated attestation.
vs.OperationNotifier.OperationFeed().Send(&feed.Event{
Type: operation.UnaggregatedAttReceived,
Data: &operation.UnAggregatedAttReceivedData{
Attestation: att,
},
})
// Determine subnet to broadcast attestation to
wantedEpoch := slots.ToEpoch(att.Data.Slot)
vals, err := vs.HeadFetcher.HeadValidatorsIndices(ctx, wantedEpoch)
if err != nil {
return nil, err
}
subnet := helpers.ComputeSubnetFromCommitteeAndSlot(uint64(len(vals)), att.Data.CommitteeIndex, att.Data.Slot)
// Broadcast the new attestation to the network.
if err := vs.P2P.BroadcastAttestation(ctx, subnet, att); err != nil {
return nil, status.Errorf(codes.Internal, "Could not broadcast attestation: %v", err)
}
go func() {
ctx = trace.NewContext(context.Background(), trace.FromContext(ctx))
attCopy := ethpb.CopyAttestation(att)
if err := vs.AttPool.SaveUnaggregatedAttestation(attCopy); err != nil {
log.WithError(err).Error("Could not handle attestation in operations service")
return
}
}()
return ðpb.AttestResponse{
AttestationDataRoot: root[:],
}, nil
}
// SubscribeCommitteeSubnets subscribes to the committee ID subnet given subscribe request.
func (vs *Server) SubscribeCommitteeSubnets(ctx context.Context, req *ethpb.CommitteeSubnetsSubscribeRequest) (*emptypb.Empty, error) {
ctx, span := trace.StartSpan(ctx, "AttesterServer.SubscribeCommitteeSubnets")
defer span.End()
if len(req.Slots) != len(req.CommitteeIds) || len(req.CommitteeIds) != len(req.IsAggregator) {
return nil, status.Error(codes.InvalidArgument, "request fields are not the same length")
}
if len(req.Slots) == 0 {
return nil, status.Error(codes.InvalidArgument, "no attester slots provided")
}
fetchValsLen := func(slot primitives.Slot) (uint64, error) {
wantedEpoch := slots.ToEpoch(slot)
vals, err := vs.HeadFetcher.HeadValidatorsIndices(ctx, wantedEpoch)
if err != nil {
return 0, err
}
return uint64(len(vals)), nil
}
// Request the head validator indices of epoch represented by the first requested
// slot.
currValsLen, err := fetchValsLen(req.Slots[0])
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not retrieve head validator length: %v", err)
}
currEpoch := slots.ToEpoch(req.Slots[0])
for i := 0; i < len(req.Slots); i++ {
// If epoch has changed, re-request active validators length
if currEpoch != slots.ToEpoch(req.Slots[i]) {
currValsLen, err = fetchValsLen(req.Slots[i])
if err != nil {
return nil, status.Errorf(codes.Internal, "Could not retrieve head validator length: %v", err)
}
currEpoch = slots.ToEpoch(req.Slots[i])
}
subnet := helpers.ComputeSubnetFromCommitteeAndSlot(currValsLen, req.CommitteeIds[i], req.Slots[i])
cache.SubnetIDs.AddAttesterSubnetID(req.Slots[i], subnet)
if req.IsAggregator[i] {
cache.SubnetIDs.AddAggregatorSubnetID(req.Slots[i], subnet)
}
}
return &emptypb.Empty{}, nil
}