2020-01-28 02:04:43 +00:00
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package blockchain
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import (
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"context"
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"github.com/pkg/errors"
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ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
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"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
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2021-01-22 17:15:49 +00:00
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"github.com/prysmaticlabs/prysm/shared/attestationutil"
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2020-01-28 02:04:43 +00:00
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"github.com/prysmaticlabs/prysm/shared/bytesutil"
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2021-05-26 18:33:46 +00:00
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"github.com/prysmaticlabs/prysm/shared/copyutil"
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2020-06-06 01:54:44 +00:00
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"github.com/prysmaticlabs/prysm/shared/params"
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2020-09-22 11:49:58 +00:00
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"github.com/prysmaticlabs/prysm/shared/timeutils"
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2020-01-28 02:04:43 +00:00
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"go.opencensus.io/trace"
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)
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// onAttestation is called whenever an attestation is received, verifies the attestation is valid and saves
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2020-06-24 03:14:44 +00:00
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// it to the DB. As a stateless function, this does not hold nor delay attestation based on the spec descriptions.
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2021-01-22 18:08:16 +00:00
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// The delay is handled by the caller in `processAttestations`.
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2020-01-28 02:04:43 +00:00
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//
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// Spec pseudocode definition:
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2020-07-25 04:55:42 +00:00
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// def on_attestation(store: Store, attestation: Attestation) -> None:
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2020-01-28 02:04:43 +00:00
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// """
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// Run ``on_attestation`` upon receiving a new ``attestation`` from either within a block or directly on the wire.
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//
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// An ``attestation`` that is asserted as invalid may be valid at a later time,
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// consider scheduling it for later processing in such case.
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// """
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2020-07-25 04:55:42 +00:00
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// validate_on_attestation(store, attestation)
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// store_target_checkpoint_state(store, attestation.data.target)
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2020-01-28 02:04:43 +00:00
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//
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2020-07-25 04:55:42 +00:00
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// # Get state at the `target` to fully validate attestation
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// target_state = store.checkpoint_states[attestation.data.target]
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2020-01-28 02:04:43 +00:00
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// indexed_attestation = get_indexed_attestation(target_state, attestation)
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// assert is_valid_indexed_attestation(target_state, indexed_attestation)
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//
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2020-07-25 04:55:42 +00:00
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// # Update latest messages for attesting indices
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// update_latest_messages(store, indexed_attestation.attesting_indices, attestation)
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2021-01-21 18:38:51 +00:00
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func (s *Service) onAttestation(ctx context.Context, a *ethpb.Attestation) error {
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2020-07-09 23:50:48 +00:00
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ctx, span := trace.StartSpan(ctx, "blockChain.onAttestation")
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2020-01-28 02:04:43 +00:00
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defer span.End()
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2021-01-19 21:41:44 +00:00
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if err := helpers.ValidateNilAttestation(a); err != nil {
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2021-01-21 18:38:51 +00:00
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return err
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2020-04-16 15:39:53 +00:00
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}
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2021-01-19 21:41:44 +00:00
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if err := helpers.ValidateSlotTargetEpoch(a.Data); err != nil {
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2021-01-21 18:38:51 +00:00
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return err
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2020-04-16 15:39:53 +00:00
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}
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2021-05-26 18:33:46 +00:00
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tgt := copyutil.CopyCheckpoint(a.Data.Target)
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2020-01-28 02:04:43 +00:00
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2021-01-20 18:27:10 +00:00
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// Note that target root check is ignored here because it was performed in sync's validation pipeline:
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// validate_aggregate_proof.go and validate_beacon_attestation.go
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// If missing target root were to fail in this method, it would have just failed in `getAttPreState`.
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2020-01-28 02:04:43 +00:00
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2020-01-30 19:06:20 +00:00
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// Retrieve attestation's data beacon block pre state. Advance pre state to latest epoch if necessary and
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// save it to the cache.
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baseState, err := s.getAttPreState(ctx, tgt)
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2020-01-28 02:04:43 +00:00
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if err != nil {
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2021-01-21 18:38:51 +00:00
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return err
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2020-01-28 02:04:43 +00:00
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}
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2020-09-04 17:25:42 +00:00
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genesisTime := baseState.GenesisTime()
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2020-01-31 20:57:01 +00:00
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2020-01-28 02:04:43 +00:00
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// Verify attestation target is from current epoch or previous epoch.
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2020-09-22 11:49:58 +00:00
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if err := s.verifyAttTargetEpoch(ctx, genesisTime, uint64(timeutils.Now().Unix()), tgt); err != nil {
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2021-01-21 18:38:51 +00:00
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return err
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2020-01-28 02:04:43 +00:00
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}
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// Verify attestation beacon block is known and not from the future.
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if err := s.verifyBeaconBlock(ctx, a.Data); err != nil {
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2021-01-21 18:38:51 +00:00
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return errors.Wrap(err, "could not verify attestation beacon block")
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2020-06-09 22:40:48 +00:00
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}
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2021-01-20 10:19:43 +00:00
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// Note that LMG GHOST and FFG consistency check is ignored because it was performed in sync's validation pipeline:
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// validate_aggregate_proof.go and validate_beacon_attestation.go
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2020-01-28 02:04:43 +00:00
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// Verify attestations can only affect the fork choice of subsequent slots.
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2020-06-06 01:54:44 +00:00
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if err := helpers.VerifySlotTime(genesisTime, a.Data.Slot+1, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
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2021-01-21 18:38:51 +00:00
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return err
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2020-01-28 02:04:43 +00:00
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}
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2021-01-22 17:15:49 +00:00
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// Use the target state to verify attesting indices are valid.
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committee, err := helpers.BeaconCommitteeFromState(baseState, a.Data.Slot, a.Data.CommitteeIndex)
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2020-01-28 02:04:43 +00:00
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if err != nil {
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2021-01-21 18:38:51 +00:00
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return err
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2020-01-28 02:04:43 +00:00
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}
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2021-01-22 17:15:49 +00:00
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indexedAtt, err := attestationutil.ConvertToIndexed(ctx, a, committee)
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if err != nil {
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return err
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}
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if err := attestationutil.IsValidAttestationIndices(ctx, indexedAtt); err != nil {
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return err
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}
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2020-01-28 02:04:43 +00:00
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2021-01-20 21:46:13 +00:00
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// Note that signature verification is ignored here because it was performed in sync's validation pipeline:
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// validate_aggregate_proof.go and validate_beacon_attestation.go
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// We assume trusted attestation in this function has verified signature.
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2020-04-14 20:27:03 +00:00
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2020-02-08 02:05:43 +00:00
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// Update forkchoice store with the new attestation for updating weight.
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2021-03-17 18:36:56 +00:00
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s.cfg.ForkChoiceStore.ProcessAttestation(ctx, indexedAtt.AttestingIndices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)
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2020-02-08 02:05:43 +00:00
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2021-01-21 18:38:51 +00:00
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return nil
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2020-01-28 02:04:43 +00:00
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}
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