prysm-pulse/beacon-chain/core/epoch/epoch_processing.go
terence tsao e321fdfafa Update to Use Crosslink in AttestationData (#1546)
* fixed epoch_processing

* test p2p

* attestation uses crosslink instead of crosslink root hash

* lint
2019-02-10 11:59:17 -06:00

371 lines
15 KiB
Go

// Package epoch contains epoch processing libraries. These libraries
// process new balance for the validators, justify and finalize new
// check points, shuffle and reassign validators to different slots and
// shards.
package epoch
import (
"fmt"
"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
"github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
"github.com/prysmaticlabs/prysm/shared/mathutil"
"github.com/prysmaticlabs/prysm/shared/params"
"github.com/prysmaticlabs/prysm/shared/ssz"
)
// CanProcessEpoch checks the eligibility to process epoch.
// The epoch can be processed every EPOCH_LENGTH.
//
// Spec pseudocode definition:
// If state.slot % EPOCH_LENGTH == 0:
func CanProcessEpoch(state *pb.BeaconState) bool {
return state.Slot%params.BeaconConfig().EpochLength == 0
}
// CanProcessEth1Data checks the eligibility to process the eth1 data.
// The eth1 data can be processed every ETH1_DATA_VOTING_PERIOD.
//
// Spec pseudocode definition:
// If next_epoch % ETH1_DATA_VOTING_PERIOD == 0
func CanProcessEth1Data(state *pb.BeaconState) bool {
return helpers.NextEpoch(state)%
params.BeaconConfig().Eth1DataVotingPeriod == 0
}
// CanProcessValidatorRegistry checks the eligibility to process validator registry.
// It checks crosslink committees last changed slot and finalized slot against
// latest change slot.
//
// Spec pseudocode definition:
// If the following are satisfied:
// * state.finalized_epoch > state.validator_registry_latest_change_epoch
// * state.latest_crosslinks[shard].epoch > state.validator_registry_update_epoch
// for every shard number shard in [(state.current_epoch_start_shard + i) %
// SHARD_COUNT for i in range(get_current_epoch_committee_count(state) *
// EPOCH_LENGTH)] (that is, for every shard in the current committees)
func CanProcessValidatorRegistry(state *pb.BeaconState) bool {
if state.FinalizedEpoch <= state.ValidatorRegistryUpdateEpoch {
return false
}
shardsProcessed := helpers.CurrentEpochCommitteeCount(state) * params.BeaconConfig().EpochLength
startShard := state.CurrentEpochStartShard
for i := startShard; i < shardsProcessed; i++ {
if state.LatestCrosslinks[i%params.BeaconConfig().ShardCount].Epoch <=
state.ValidatorRegistryUpdateEpoch {
return false
}
}
return true
}
// ProcessEth1Data processes eth1 block deposit roots by checking its vote count.
// With sufficient votes (>2*ETH1_DATA_VOTING_PERIOD), it then
// marks the voted Eth1 data as the latest data set.
//
// Official spec definition:
// if next_epoch % ETH1_DATA_VOTING_PERIOD == 0:
// if eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH for
// some eth1_data_vote in state.eth1_data_votes.
// (ie. more than half the votes in this voting period were for that value)
// Set state.latest_eth1_data = eth1_data_vote.eth1_data.
// Set state.eth1_data_votes = [].
//
func ProcessEth1Data(state *pb.BeaconState) *pb.BeaconState {
if helpers.NextEpoch(state)%params.BeaconConfig().Eth1DataVotingPeriod == 0 {
for _, eth1DataVote := range state.Eth1DataVotes {
if eth1DataVote.VoteCount*2 > params.BeaconConfig().Eth1DataVotingPeriod {
state.LatestEth1Data.DepositRootHash32 = eth1DataVote.Eth1Data.DepositRootHash32
state.LatestEth1Data.BlockHash32 = eth1DataVote.Eth1Data.BlockHash32
}
}
state.Eth1DataVotes = make([]*pb.Eth1DataVote, 0)
}
return state
}
// ProcessJustification processes for justified slot by comparing
// epoch boundary balance and total balance.
//
// Spec pseudocode definition:
// Set state.previous_justified_epoch = state.justified_epoch.
// Set state.justification_bitfield = (state.justification_bitfield * 2) % 2**64.
// Set state.justification_bitfield |= 2 and state.justified_epoch =
// slot_to_epoch(state.slot) - 2 if 3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance
// Set state.justification_bitfield |= 1 and state.justified_epoch =
// slot_to_epoch(state.slot) - 1 if 3 * this_epoch_boundary_attesting_balance >= 2 * total_balance
func ProcessJustification(
state *pb.BeaconState,
thisEpochBoundaryAttestingBalance uint64,
prevEpochBoundaryAttestingBalance uint64,
totalBalance uint64) *pb.BeaconState {
state.PreviousJustifiedEpoch = state.JustifiedEpoch
// Shifts all the bits over one to create a new bit for the recent epoch.
state.JustificationBitfield = state.JustificationBitfield * 2
// If prev prev epoch was justified then we ensure the 2nd bit in the bitfield is set,
// assign new justified slot to 2 * EPOCH_LENGTH before.
if 3*prevEpochBoundaryAttestingBalance >= 2*totalBalance {
state.JustificationBitfield |= 2
state.JustifiedEpoch = helpers.CurrentEpoch(state) - 2
}
// If this epoch was justified then we ensure the 1st bit in the bitfield is set,
// assign new justified slot to 1 * EPOCH_LENGTH before.
if 3*thisEpochBoundaryAttestingBalance >= 2*totalBalance {
state.JustificationBitfield |= 1
state.JustifiedEpoch = helpers.CurrentEpoch(state) - 1
}
return state
}
// ProcessFinalization processes for finalized slot by checking
// consecutive justified slots.
//
// Spec pseudocode definition:
// Set state.finalized_epoch = state.previous_justified_epoch if any of the following are true:
// state.previous_justified_epoch == slot_to_epoch(state.slot) - 2 and state.justification_bitfield % 4 == 3
// state.previous_justified_epoch == slot_to_epoch(state.slot) - 3 and state.justification_bitfield % 8 == 7
// state.previous_justified_epoch == slot_to_epoch(state.slot) - 4 and state.justification_bitfield % 16 in (15, 14)
func ProcessFinalization(state *pb.BeaconState) *pb.BeaconState {
if state.PreviousJustifiedEpoch == helpers.CurrentEpoch(state)-2 &&
state.JustificationBitfield%4 == 3 {
state.FinalizedEpoch = state.JustifiedEpoch
return state
}
if state.PreviousJustifiedEpoch == helpers.CurrentEpoch(state)-3 &&
state.JustificationBitfield%8 == 7 {
state.FinalizedEpoch = state.JustifiedEpoch
return state
}
if state.PreviousJustifiedEpoch == helpers.CurrentEpoch(state)-4 &&
(state.JustificationBitfield%16 == 15 ||
state.JustificationBitfield%16 == 14) {
state.FinalizedEpoch = state.JustifiedEpoch
return state
}
return state
}
// ProcessCrosslinks goes through each crosslink committee and check
// crosslink committee's attested balance * 3 is greater than total balance *2.
// If it's greater then beacon node updates crosslink committee with
// the state epoch and wining root.
//
// Spec pseudocode definition:
// For every slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(next_epoch)),
// let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`.
// For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute:
// Set state.latest_crosslinks[shard] = Crosslink(
// epoch=current_epoch, shard_block_root=winning_root(crosslink_committee))
// if 3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)
func ProcessCrosslinks(
state *pb.BeaconState,
thisEpochAttestations []*pb.PendingAttestationRecord,
prevEpochAttestations []*pb.PendingAttestationRecord) (*pb.BeaconState, error) {
prevEpoch := helpers.PrevEpoch(state)
currentEpoch := helpers.CurrentEpoch(state)
nextEpoch := helpers.NextEpoch(state)
startSlot := helpers.StartSlot(prevEpoch)
endSlot := helpers.StartSlot(nextEpoch)
for i := startSlot; i < endSlot; i++ {
crosslinkCommittees, err := helpers.CrosslinkCommitteesAtSlot(state, i, false)
if err != nil {
return nil, fmt.Errorf("could not get committees for slot %d: %v", i, err)
}
for _, crosslinkCommittee := range crosslinkCommittees {
shard := crosslinkCommittee.Shard
committee := crosslinkCommittee.Committee
attestingBalance, err := TotalAttestingBalance(state, shard, thisEpochAttestations, prevEpochAttestations)
if err != nil {
return nil, fmt.Errorf("could not get attesting balance for shard committee %d: %v", shard, err)
}
totalBalance := TotalBalance(state, committee)
if attestingBalance*3 > totalBalance*2 {
winningRoot, err := winningRoot(state, shard, thisEpochAttestations, prevEpochAttestations)
if err != nil {
return nil, fmt.Errorf("could not get winning root: %v", err)
}
state.LatestCrosslinks[shard] = &pb.Crosslink{
Epoch: currentEpoch,
ShardBlockRootHash32: winningRoot,
}
}
}
}
return state, nil
}
// ProcessEjections iterates through every validator and find the ones below
// ejection balance and eject them.
//
// Spec pseudocode definition:
// def process_ejections(state: BeaconState) -> None:
// """
// Iterate through the validator registry
// and eject active validators with balance below ``EJECTION_BALANCE``.
// """
// for index in get_active_validator_indices(state.validator_registry, current_epoch(state)):
// if state.validator_balances[index] < EJECTION_BALANCE:
// exit_validator(state, index)
func ProcessEjections(state *pb.BeaconState) (*pb.BeaconState, error) {
var err error
activeValidatorIndices := helpers.ActiveValidatorIndices(state.ValidatorRegistry, helpers.CurrentEpoch(state))
for _, index := range activeValidatorIndices {
if state.ValidatorBalances[index] < params.BeaconConfig().EjectionBalance {
state, err = validators.ExitValidator(state, index)
if err != nil {
return nil, fmt.Errorf("could not exit validator %d: %v", index, err)
}
}
}
return state, nil
}
// ProcessPrevSlotShardSeed computes and sets current epoch's calculation slot
// and start shard to previous epoch. Then it returns the updated state.
//
// Spec pseudocode definition:
// Set state.previous_epoch_randao_mix = state.current_epoch_randao_mix
// Set state.previous_calculation_epoch = state.current_calculation_epoch
// Set state.previous_epoch_seed = state.current_epoch_seed.
func ProcessPrevSlotShardSeed(state *pb.BeaconState) *pb.BeaconState {
state.PreviousCalculationEpoch = state.CurrentCalculationEpoch
state.PreviousEpochStartShard = state.CurrentEpochStartShard
state.PreviousEpochSeedHash32 = state.CurrentEpochSeedHash32
return state
}
// ProcessValidatorRegistry computes and sets new validator registry fields,
// reshuffles shard committees and returns the recomputed state with the updated registry.
//
// Spec pseudocode definition:
// Set state.current_calculation_epoch = next_epoch
// Set state.current_epoch_start_shard = (state.current_epoch_start_shard +
// get_current_epoch_committee_count(state)) % SHARD_COUNT
// Set state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)
func ProcessValidatorRegistry(
state *pb.BeaconState) (*pb.BeaconState, error) {
state.CurrentCalculationEpoch = state.Slot
nextStartShard := (state.CurrentEpochStartShard +
helpers.CurrentEpochCommitteeCount(state)*params.BeaconConfig().EpochLength) %
params.BeaconConfig().EpochLength
state.CurrentEpochStartShard = nextStartShard
var randaoMixSlot uint64
if state.CurrentCalculationEpoch > params.BeaconConfig().SeedLookahead {
randaoMixSlot = state.CurrentCalculationEpoch -
params.BeaconConfig().SeedLookahead
}
randaoMix, err := helpers.RandaoMix(state, randaoMixSlot)
if err != nil {
return nil, fmt.Errorf("could not get randaoMix mix: %v", err)
}
state.CurrentEpochSeedHash32 = randaoMix
return state, nil
}
// ProcessPartialValidatorRegistry processes the portion of validator registry
// fields, it doesn't set registry latest change slot. This only gets called if
// validator registry update did not happen.
//
// Spec pseudocode definition:
// Let epochs_since_last_registry_change = current_epoch -
// state.validator_registry_update_epoch
// If epochs_since_last_registry_update > 1 and
// epochs_since_last_registry_change is an exact power of 2:
// set state.current_calculation_epoch = next_epoch
// set state.current_epoch_seed = generate_seed(
// state, state.current_calculation_epoch)
func ProcessPartialValidatorRegistry(state *pb.BeaconState) (*pb.BeaconState, error) {
epochsSinceLastRegistryChange := helpers.CurrentEpoch(state) -
state.ValidatorRegistryUpdateEpoch
if epochsSinceLastRegistryChange > 1 &&
mathutil.IsPowerOf2(epochsSinceLastRegistryChange) {
state.CurrentCalculationEpoch = helpers.NextEpoch(state)
seed, err := helpers.GenerateSeed(state, state.CurrentCalculationEpoch)
if err != nil {
return nil, fmt.Errorf("could not generate seed: %v", err)
}
state.CurrentEpochSeedHash32 = seed[:]
}
return state, nil
}
// CleanupAttestations removes any attestation in state's latest attestations
// such that the attestation slot is lower than state slot minus epoch length.
// Spec pseudocode definition:
// Remove any attestation in state.latest_attestations such
// that slot_to_epoch(att.data.slot) < slot_to_epoch(state) - 1
func CleanupAttestations(state *pb.BeaconState) *pb.BeaconState {
currEpoch := helpers.CurrentEpoch(state)
var latestAttestations []*pb.PendingAttestationRecord
for _, attestation := range state.LatestAttestations {
if helpers.SlotToEpoch(attestation.Data.Slot) >= currEpoch {
latestAttestations = append(latestAttestations, attestation)
}
}
state.LatestAttestations = latestAttestations
return state
}
// UpdateLatestIndexRoots updates the latest index roots. Index root
// is computed by hashing validator indices of the next epoch + delay.
//
// Spec pseudocode definition:
// Let e = state.slot // EPOCH_LENGTH.
// Set state.latest_index_roots[(next_epoch + ENTRY_EXIT_DELAY) %
// LATEST_INDEX_ROOTS_LENGTH] =
// hash_tree_root(get_active_validator_indices(state,
// next_epoch + ENTRY_EXIT_DELAY))
func UpdateLatestIndexRoots(state *pb.BeaconState) (*pb.BeaconState, error) {
nextEpoch := helpers.NextEpoch(state) + params.BeaconConfig().EntryExitDelay
validatorIndices := helpers.ActiveValidatorIndices(state.ValidatorRegistry, nextEpoch)
indexRoot, err := ssz.TreeHash(validatorIndices)
if err != nil {
return nil, fmt.Errorf("could not hash tree root: %v", err)
}
state.LatestIndexRootHash32S[nextEpoch%params.BeaconConfig().LatestIndexRootsLength] =
indexRoot[:]
return state, nil
}
// UpdateLatestPenalizedBalances updates the latest penalized balances. It transfers
// the amount from the current epoch index to next epoch index.
//
// Spec pseudocode definition:
// Set state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] =
// state.latest_penalized_balances[current_epoch % LATEST_PENALIZED_EXIT_LENGTH].
func UpdateLatestPenalizedBalances(state *pb.BeaconState) *pb.BeaconState {
currentEpoch := helpers.CurrentEpoch(state) % params.BeaconConfig().LatestPenalizedExitLength
nextEpoch := helpers.NextEpoch(state) % params.BeaconConfig().LatestPenalizedExitLength
state.LatestPenalizedBalances[nextEpoch] = state.LatestPenalizedBalances[currentEpoch]
return state
}
// UpdateLatestRandaoMixes updates the latest seed mixes. It transfers
// the seed mix of current epoch to next epoch.
//
// Spec pseudocode definition:
// Set state.latest_randao_mixes[next_epoch % LATEST_RANDAO_MIXES_LENGTH] =
// get_randao_mix(state, current_epoch).
func UpdateLatestRandaoMixes(state *pb.BeaconState) (*pb.BeaconState, error) {
nextEpoch := helpers.NextEpoch(state) % params.BeaconConfig().LatestRandaoMixesLength
randaoMix, err := helpers.RandaoMix(state, helpers.CurrentEpoch(state))
if err != nil {
return nil, fmt.Errorf("could not get randaoMix mix: %v", err)
}
state.LatestRandaoMixesHash32S[nextEpoch] = randaoMix
return state, nil
}