The core protocol of WoopChain
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woop/internal/chain/engine.go

567 lines
18 KiB

package chain
import (
"bytes"
"math/big"
"sort"
harmony_bls "github.com/harmony-one/harmony/crypto/bls"
"github.com/ethereum/go-ethereum/common"
"github.com/harmony-one/harmony/block"
"github.com/harmony-one/harmony/consensus/engine"
"github.com/harmony-one/harmony/consensus/quorum"
"github.com/harmony-one/harmony/consensus/reward"
"github.com/harmony-one/harmony/consensus/signature"
"github.com/harmony-one/harmony/core/state"
"github.com/harmony-one/harmony/core/types"
"github.com/harmony-one/harmony/internal/utils"
"github.com/harmony-one/harmony/multibls"
"github.com/harmony-one/harmony/shard"
"github.com/harmony-one/harmony/shard/committee"
"github.com/harmony-one/harmony/staking/availability"
"github.com/harmony-one/harmony/staking/slash"
staking "github.com/harmony-one/harmony/staking/types"
"github.com/pkg/errors"
)
type engineImpl struct {
beacon engine.ChainReader
}
// Engine is an algorithm-agnostic consensus engine.
var Engine = &engineImpl{nil}
func (e *engineImpl) Beaconchain() engine.ChainReader {
return e.beacon
}
// SetBeaconchain assigns the beaconchain handle used
func (e *engineImpl) SetBeaconchain(beaconchain engine.ChainReader) {
e.beacon = beaconchain
}
// VerifyHeader checks whether a header conforms to the consensus rules of the bft engine.
// Note that each block header contains the bls signature of the parent block
func (e *engineImpl) VerifyHeader(chain engine.ChainReader, header *block.Header, seal bool) error {
parentHeader := chain.GetHeader(header.ParentHash(), header.Number().Uint64()-1)
if parentHeader == nil {
return engine.ErrUnknownAncestor
}
if seal {
if err := e.VerifySeal(chain, header); err != nil {
return err
}
}
return nil
}
// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers
// concurrently. The method returns a quit channel to abort the operations and
// a results channel to retrieve the async verifications.
func (e *engineImpl) VerifyHeaders(chain engine.ChainReader, headers []*block.Header, seals []bool) (chan<- struct{}, <-chan error) {
abort, results := make(chan struct{}), make(chan error, len(headers))
go func() {
for i, header := range headers {
err := e.VerifyHeader(chain, header, seals[i])
select {
case <-abort:
return
case results <- err:
}
}
}()
return abort, results
}
// ReadPublicKeysFromLastBlock finds the public keys of last block's committee
func ReadPublicKeysFromLastBlock(
bc engine.ChainReader, header *block.Header,
) ([]harmony_bls.PublicKeyWrapper, error) {
parentHeader := bc.GetHeaderByHash(header.ParentHash())
return GetPublicKeys(bc, parentHeader, false)
}
// VerifyShardState implements Engine, checking the shardstate is valid at epoch transition
func (e *engineImpl) VerifyShardState(
bc engine.ChainReader, beacon engine.ChainReader, header *block.Header,
) error {
if bc.ShardID() != header.ShardID() {
return errors.Errorf(
"[VerifyShardState] shardID not match %d %d", bc.ShardID(), header.ShardID(),
)
}
headerShardStateBytes := header.ShardState()
// TODO: figure out leader withhold shardState
if len(headerShardStateBytes) == 0 {
return nil
}
shardState, err := bc.SuperCommitteeForNextEpoch(beacon, header, true)
if err != nil {
return err
}
isStaking := false
if shardState.Epoch != nil && bc.Config().IsStaking(shardState.Epoch) {
isStaking = true
}
shardStateBytes, err := shard.EncodeWrapper(*shardState, isStaking)
if err != nil {
return errors.Wrapf(
err, "[VerifyShardState] ShardState Encoding had error",
)
}
if !bytes.Equal(shardStateBytes, headerShardStateBytes) {
return errors.New("shard state header did not match as expected")
}
return nil
}
// VerifySeal implements Engine, checking whether the given block's parent block satisfies
// the PoS difficulty requirements, i.e. >= 2f+1 valid signatures from the committee
// Note that each block header contains the bls signature of the parent block
func (e *engineImpl) VerifySeal(chain engine.ChainReader, header *block.Header) error {
if chain.CurrentHeader().Number().Uint64() <= uint64(1) {
return nil
}
if header == nil {
return errors.New("[VerifySeal] nil block header")
}
publicKeys, err := ReadPublicKeysFromLastBlock(chain, header)
if err != nil {
return errors.New("[VerifySeal] Cannot retrieve publickeys from last block")
}
sig := header.LastCommitSignature()
payload := append(sig[:], header.LastCommitBitmap()...)
aggSig, mask, err := ReadSignatureBitmapByPublicKeys(payload, publicKeys)
if err != nil {
return errors.New(
"[VerifySeal] Unable to deserialize the LastCommitSignature" +
" and LastCommitBitmap in Block Header",
)
}
parentHash := header.ParentHash()
parentHeader := chain.GetHeader(parentHash, header.Number().Uint64()-1)
if parentHeader == nil {
return errors.New(
"[VerifySeal] no parent header found",
)
}
if chain.Config().IsStaking(parentHeader.Epoch()) {
slotList, err := chain.ReadShardState(parentHeader.Epoch())
if err != nil {
return errors.Wrapf(err, "cannot decoded shard state")
}
subComm, err := slotList.FindCommitteeByID(parentHeader.ShardID())
if err != nil {
return err
}
// TODO(audit): reuse a singleton decider and not recreate it for every single block
d := quorum.NewDecider(
quorum.SuperMajorityStake, subComm.ShardID,
)
d.SetMyPublicKeyProvider(func() (multibls.PublicKeys, error) {
return nil, nil
})
if _, err := d.SetVoters(subComm, slotList.Epoch); err != nil {
return err
}
if !d.IsQuorumAchievedByMask(mask) {
return errors.New(
"[VerifySeal] Not enough voting power in LastCommitSignature from Block Header",
)
}
} else {
parentQuorum, err := QuorumForBlock(chain, parentHeader, false)
if err != nil {
return errors.Wrapf(err,
"cannot calculate quorum for block %s", header.Number())
}
if count := utils.CountOneBits(mask.Bitmap); count < int64(parentQuorum) {
return errors.Errorf(
"[VerifySeal] need %d signature in LastCommitSignature have %d",
parentQuorum, count,
)
}
}
lastCommitPayload := signature.ConstructCommitPayload(chain,
parentHeader.Epoch(), parentHeader.Hash(), parentHeader.Number().Uint64(), parentHeader.ViewID().Uint64())
if !aggSig.VerifyHash(mask.AggregatePublic, lastCommitPayload) {
const msg = "[VerifySeal] Unable to verify aggregated signature from last block: %x"
return errors.Errorf(msg, payload)
}
return nil
}
// Finalize implements Engine, accumulating the block rewards,
// setting the final state and assembling the block.
// sigsReady signal indicates whether the commit sigs are populated in the header object.
func (e *engineImpl) Finalize(
chain engine.ChainReader, header *block.Header,
state *state.DB, txs []*types.Transaction,
receipts []*types.Receipt, outcxs []*types.CXReceipt,
incxs []*types.CXReceiptsProof, stks staking.StakingTransactions,
doubleSigners slash.Records, sigsReady chan bool, viewID func() uint64,
) (*types.Block, reward.Reader, error) {
isBeaconChain := header.ShardID() == shard.BeaconChainShardID
inStakingEra := chain.Config().IsStaking(header.Epoch())
// Process Undelegations, set LastEpochInCommittee and set EPoS status
// Needs to be before AccumulateRewardsAndCountSigs
if IsCommitteeSelectionBlock(chain, header) {
if err := payoutUndelegations(chain, header, state); err != nil {
return nil, nil, err
}
// Needs to be after payoutUndelegations because payoutUndelegations
// depends on the old LastEpochInCommittee
if err := setLastEpochInCommittee(header, state); err != nil {
return nil, nil, err
}
curShardState, err := chain.ReadShardState(chain.CurrentBlock().Epoch())
if err != nil {
return nil, nil, err
}
// Needs to be before AccumulateRewardsAndCountSigs because
// ComputeAndMutateEPOSStatus depends on the signing counts that's
// consistent with the counts when the new shardState was proposed.
// Refer to committee.IsEligibleForEPoSAuction()
for _, addr := range curShardState.StakedValidators().Addrs {
if err := availability.ComputeAndMutateEPOSStatus(
chain, state, addr,
); err != nil {
return nil, nil, err
}
}
}
// Accumulate block rewards and commit the final state root
// Header seems complete, assemble into a block and return
payout, err := AccumulateRewardsAndCountSigs(
chain, state, header, e.Beaconchain(), sigsReady,
)
if err != nil {
return nil, nil, err
}
// Apply slashes
if isBeaconChain && inStakingEra && len(doubleSigners) > 0 {
if err := applySlashes(chain, header, state, doubleSigners); err != nil {
return nil, nil, err
}
} else if len(doubleSigners) > 0 {
return nil, nil, errors.New("slashes proposed in non-beacon chain or non-staking epoch")
}
// ViewID setting needs to happen after commig sig reward logic for pipelining reason.
// TODO: make the viewID fetch from caller of the block proposal.
header.SetViewID(new(big.Int).SetUint64(viewID()))
// Finalize the state root
header.SetRoot(state.IntermediateRoot(chain.Config().IsS3(header.Epoch())))
// TODO: put block version and eth transaction in new block
return types.NewBlock(header, txs, receipts, outcxs, incxs, stks), payout, nil
}
// Withdraw unlocked tokens to the delegators' accounts
func payoutUndelegations(
chain engine.ChainReader, header *block.Header, state *state.DB,
) error {
currentHeader := chain.CurrentHeader()
nowEpoch, blockNow := currentHeader.Epoch(), currentHeader.Number()
utils.AnalysisStart("payoutUndelegations", nowEpoch, blockNow)
defer utils.AnalysisEnd("payoutUndelegations", nowEpoch, blockNow)
validators, err := chain.ReadValidatorList()
countTrack := map[common.Address]int{}
if err != nil {
const msg = "[Finalize] failed to read all validators"
return errors.New(msg)
}
// Payout undelegated/unlocked tokens
for _, validator := range validators {
wrapper, err := state.ValidatorWrapper(validator)
if err != nil {
return errors.New(
"[Finalize] failed to get validator from state to finalize",
)
}
lockPeriod := GetLockPeriodInEpoch(chain, header.Epoch())
for i := range wrapper.Delegations {
delegation := &wrapper.Delegations[i]
totalWithdraw := delegation.RemoveUnlockedUndelegations(
header.Epoch(), wrapper.LastEpochInCommittee, lockPeriod,
)
state.AddBalance(delegation.DelegatorAddress, totalWithdraw)
}
countTrack[validator] = len(wrapper.Delegations)
}
utils.Logger().Info().
Uint64("epoch", header.Epoch().Uint64()).
Uint64("block-number", header.Number().Uint64()).
Interface("count-track", countTrack).
Msg("paid out delegations")
return nil
}
// IsCommitteeSelectionBlock checks if the given header is for the committee selection block
// which can only occur on beacon chain and if epoch > pre-staking epoch.
func IsCommitteeSelectionBlock(chain engine.ChainReader, header *block.Header) bool {
isBeaconChain := header.ShardID() == shard.BeaconChainShardID
inPreStakingEra := chain.Config().IsPreStaking(header.Epoch())
return isBeaconChain && header.IsLastBlockInEpoch() && inPreStakingEra
}
func setLastEpochInCommittee(header *block.Header, state *state.DB) error {
newShardState, err := header.GetShardState()
if err != nil {
const msg = "[Finalize] failed to read shard state"
return errors.New(msg)
}
for _, addr := range newShardState.StakedValidators().Addrs {
wrapper, err := state.ValidatorWrapper(addr)
if err != nil {
return errors.New(
"[Finalize] failed to get validator from state to finalize",
)
}
wrapper.LastEpochInCommittee = newShardState.Epoch
}
return nil
}
func applySlashes(
chain engine.ChainReader,
header *block.Header,
state *state.DB,
doubleSigners slash.Records,
) error {
type keyStruct struct {
height uint64
viewID uint64
shardID uint32
epoch uint64
}
groupedRecords := map[keyStruct]slash.Records{}
// First group slashes by same signed blocks
for i := range doubleSigners {
thisKey := keyStruct{
height: doubleSigners[i].Evidence.Height,
viewID: doubleSigners[i].Evidence.ViewID,
shardID: doubleSigners[i].Evidence.Moment.ShardID,
epoch: doubleSigners[i].Evidence.Moment.Epoch.Uint64(),
}
groupedRecords[thisKey] = append(groupedRecords[thisKey], doubleSigners[i])
}
sortedKeys := []keyStruct{}
for key := range groupedRecords {
sortedKeys = append(sortedKeys, key)
}
// Sort them so the slashes are always consistent
sort.SliceStable(sortedKeys, func(i, j int) bool {
if sortedKeys[i].shardID < sortedKeys[j].shardID {
return true
} else if sortedKeys[i].height < sortedKeys[j].height {
return true
} else if sortedKeys[i].viewID < sortedKeys[j].viewID {
return true
}
return false
})
// Do the slashing by groups in the sorted order
for _, key := range sortedKeys {
records := groupedRecords[key]
superCommittee, err := chain.ReadShardState(big.NewInt(int64(key.epoch)))
if err != nil {
return errors.New("could not read shard state")
}
subComm, err := superCommittee.FindCommitteeByID(key.shardID)
if err != nil {
return errors.New("could not find shard committee")
}
// Apply the slashes, invariant: assume been verified as legit slash by this point
var slashApplied *slash.Application
votingPower, err := lookupVotingPower(
big.NewInt(int64(key.epoch)), subComm,
)
if err != nil {
return errors.Wrapf(err, "could not lookup cached voting power in slash application")
}
rate := slash.Rate(votingPower, records)
utils.Logger().Info().
Str("rate", rate.String()).
RawJSON("records", []byte(records.String())).
Msg("now applying slash to state during block finalization")
if slashApplied, err = slash.Apply(
chain,
state,
records,
rate,
); err != nil {
return errors.New("[Finalize] could not apply slash")
}
utils.Logger().Info().
Str("rate", rate.String()).
RawJSON("records", []byte(records.String())).
RawJSON("applied", []byte(slashApplied.String())).
Msg("slash applied successfully")
}
return nil
}
// QuorumForBlock returns the quorum for the given block header.
func QuorumForBlock(
chain engine.ChainReader, h *block.Header, reCalculate bool,
) (quorum int, err error) {
ss := new(shard.State)
if reCalculate {
ss, _ = committee.WithStakingEnabled.Compute(h.Epoch(), chain)
} else {
ss, err = chain.ReadShardState(h.Epoch())
if err != nil {
return 0, errors.Wrapf(
err, "failed to read shard state of epoch %d", h.Epoch().Uint64(),
)
}
}
subComm, err := ss.FindCommitteeByID(h.ShardID())
if err != nil {
return 0, errors.Errorf("cannot find shard %d in shard state", h.ShardID())
}
return (len(subComm.Slots))*2/3 + 1, nil
}
// Similiar to VerifyHeader, which is only for verifying the block headers of one's own chain, this verification
// is used for verifying "incoming" block header against commit signature and bitmap sent from the other chain cross-shard via libp2p.
// i.e. this header verification api is more flexible since the caller specifies which commit signature and bitmap to use
// for verifying the block header, which is necessary for cross-shard block header verification. Example of such is cross-shard transaction.
func (e *engineImpl) VerifyHeaderWithSignature(chain engine.ChainReader, header *block.Header, commitSig []byte, commitBitmap []byte, reCalculate bool) error {
if chain.Config().IsStaking(header.Epoch()) {
// Never recalculate after staking is enabled
reCalculate = false
}
publicKeys, err := GetPublicKeys(chain, header, reCalculate)
if err != nil {
return errors.New("[VerifyHeaderWithSignature] Cannot get publickeys for block header")
}
payload := append(commitSig[:], commitBitmap[:]...)
aggSig, mask, err := ReadSignatureBitmapByPublicKeys(payload, publicKeys)
if err != nil {
return errors.Wrapf(
err,
"[VerifyHeaderWithSignature] Unable to deserialize signatures",
)
}
if e := header.Epoch(); chain.Config().IsStaking(e) {
slotList, err := chain.ReadShardState(e)
if err != nil {
return errors.Wrapf(err, "cannot read shard state")
}
subComm, err := slotList.FindCommitteeByID(header.ShardID())
if err != nil {
return err
}
// TODO(audit): reuse a singleton decider and not recreate it for every single block
d := quorum.NewDecider(quorum.SuperMajorityStake, subComm.ShardID)
d.SetMyPublicKeyProvider(func() (multibls.PublicKeys, error) {
return nil, nil
})
if _, err := d.SetVoters(subComm, e); err != nil {
return err
}
if !d.IsQuorumAchievedByMask(mask) {
return errors.New(
"[VerifySeal] Not enough voting power in commitSignature from Block Header",
)
}
} else {
quorumCount, err := QuorumForBlock(chain, header, reCalculate)
if err != nil {
return errors.Wrapf(err,
"cannot calculate quorum for block %s", header.Number())
}
if count := utils.CountOneBits(mask.Bitmap); count < int64(quorumCount) {
return errors.New(
"[VerifyHeaderWithSignature] Not enough signature in commitSignature from Block Header",
)
}
}
commitPayload := signature.ConstructCommitPayload(chain,
header.Epoch(), header.Hash(), header.Number().Uint64(), header.ViewID().Uint64())
if !aggSig.VerifyHash(mask.AggregatePublic, commitPayload) {
return errors.New("[VerifySeal] Unable to verify aggregated signature for block")
}
return nil
}
// GetPublicKeys finds the public keys of the committee that signed the block header
func GetPublicKeys(
chain engine.ChainReader, header *block.Header, reCalculate bool,
) ([]harmony_bls.PublicKeyWrapper, error) {
if header == nil {
return nil, errors.New("nil header provided")
}
shardState := new(shard.State)
var err error
if reCalculate {
shardState, _ = committee.WithStakingEnabled.Compute(header.Epoch(), chain)
} else {
shardState, err = chain.ReadShardState(header.Epoch())
if err != nil {
return nil, errors.Wrapf(
err, "failed to read shard state of epoch %d", header.Epoch().Uint64(),
)
}
}
subCommittee, err := shardState.FindCommitteeByID(header.ShardID())
if err != nil {
return nil, errors.Wrapf(
err,
"cannot find shard in the shard state at block %d shard %d",
header.Number(),
header.ShardID(),
)
}
return subCommittee.BLSPublicKeys()
}
// GetLockPeriodInEpoch returns the delegation lock period for the given chain
func GetLockPeriodInEpoch(chain engine.ChainReader, epoch *big.Int) int {
lockPeriod := staking.LockPeriodInEpoch
if chain.Config().IsRedelegation(epoch) {
lockPeriod = staking.LockPeriodInEpoch
} else if chain.Config().IsQuickUnlock(epoch) {
lockPeriod = staking.LockPeriodInEpochV2
}
return lockPeriod
}