prysm-pulse/beacon-chain/core/altair/attestation.go
terence tsao 38787353a2
Attestation: get participation status (#9340)
* Add participation flag indics matching helpers

* Gazelle

* Tests

* Update BUILD.bazel

* Update attestation.go
2021-08-09 16:35:46 +00:00

115 lines
4.6 KiB
Go

package altair
import (
"bytes"
"github.com/pkg/errors"
types "github.com/prysmaticlabs/eth2-types"
"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
"github.com/prysmaticlabs/prysm/beacon-chain/state"
ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
"github.com/prysmaticlabs/prysm/shared/attestationutil"
"github.com/prysmaticlabs/prysm/shared/params"
)
// HasValidatorFlag returns true if the flag at position has set.
func HasValidatorFlag(flag, flagPosition uint8) bool {
return ((flag >> flagPosition) & 1) == 1
}
// AddValidatorFlag adds new validator flag to existing one.
func AddValidatorFlag(flag, flagPosition uint8) uint8 {
return flag | (1 << flagPosition)
}
// AttestationParticipationFlagIndices retrieves a map of attestation scoring based on Altair's participation flag indices.
// This is used to facilitate process attestation during state transition and during upgrade to altair state.
//
// Spec code:
// def get_attestation_participation_flag_indices(state: BeaconState,
// data: AttestationData,
// inclusion_delay: uint64) -> Sequence[int]:
// """
// Return the flag indices that are satisfied by an attestation.
// """
// if data.target.epoch == get_current_epoch(state):
// justified_checkpoint = state.current_justified_checkpoint
// else:
// justified_checkpoint = state.previous_justified_checkpoint
//
// # Matching roots
// is_matching_source = data.source == justified_checkpoint
// is_matching_target = is_matching_source and data.target.root == get_block_root(state, data.target.epoch)
// is_matching_head = is_matching_target and data.beacon_block_root == get_block_root_at_slot(state, data.slot)
// assert is_matching_source
//
// participation_flag_indices = []
// if is_matching_source and inclusion_delay <= integer_squareroot(SLOTS_PER_EPOCH):
// participation_flag_indices.append(TIMELY_SOURCE_FLAG_INDEX)
// if is_matching_target and inclusion_delay <= SLOTS_PER_EPOCH:
// participation_flag_indices.append(TIMELY_TARGET_FLAG_INDEX)
// if is_matching_head and inclusion_delay == MIN_ATTESTATION_INCLUSION_DELAY:
// participation_flag_indices.append(TIMELY_HEAD_FLAG_INDEX)
//
// return participation_flag_indices
func AttestationParticipationFlagIndices(beaconState state.BeaconStateAltair, data *ethpb.AttestationData, delay types.Slot) (map[uint8]bool, error) {
currEpoch := helpers.CurrentEpoch(beaconState)
var justifiedCheckpt *ethpb.Checkpoint
if data.Target.Epoch == currEpoch {
justifiedCheckpt = beaconState.CurrentJustifiedCheckpoint()
} else {
justifiedCheckpt = beaconState.PreviousJustifiedCheckpoint()
}
matchedSrc, matchedTgt, matchedHead, err := MatchingStatus(beaconState, data, justifiedCheckpt)
if err != nil {
return nil, err
}
if !matchedSrc {
return nil, errors.New("source epoch does not match")
}
participatedFlags := make(map[uint8]bool)
cfg := params.BeaconConfig()
sourceFlagIndex := cfg.TimelySourceFlagIndex
targetFlagIndex := cfg.TimelyTargetFlagIndex
headFlagIndex := cfg.TimelyHeadFlagIndex
slotsPerEpoch := cfg.SlotsPerEpoch
sqtRootSlots := cfg.SqrRootSlotsPerEpoch
if matchedSrc && delay <= sqtRootSlots {
participatedFlags[sourceFlagIndex] = true
}
matchedSrcTgt := matchedSrc && matchedTgt
if matchedSrcTgt && delay <= slotsPerEpoch {
participatedFlags[targetFlagIndex] = true
}
matchedSrcTgtHead := matchedHead && matchedSrcTgt
if matchedSrcTgtHead && delay == cfg.MinAttestationInclusionDelay {
participatedFlags[headFlagIndex] = true
}
return participatedFlags, nil
}
// MatchingStatus returns the matching statues for attestation data's source target and head.
//
// Spec code:
// is_matching_source = data.source == justified_checkpoint
// is_matching_target = is_matching_source and data.target.root == get_block_root(state, data.target.epoch)
// is_matching_head = is_matching_target and data.beacon_block_root == get_block_root_at_slot(state, data.slot)
func MatchingStatus(beaconState state.BeaconState, data *ethpb.AttestationData, cp *ethpb.Checkpoint) (matchedSrc bool, matchedTgt bool, matchedHead bool, err error) {
matchedSrc = attestationutil.CheckPointIsEqual(data.Source, cp)
r, err := helpers.BlockRoot(beaconState, data.Target.Epoch)
if err != nil {
return false, false, false, err
}
matchedTgt = bytes.Equal(r, data.Target.Root)
r, err = helpers.BlockRootAtSlot(beaconState, data.Slot)
if err != nil {
return false, false, false, err
}
matchedHead = bytes.Equal(r, data.BeaconBlockRoot)
return
}