neo-go/pkg/consensus/consensus.go
Ekaterina Pavlova 5bb7c6b715 services: update logs flush after services shutdown
Added sync logs for every service separately to provide the ability to
have a custom logger for each service. This commit makes the code follow
the zap usages rules: `Sync calls the underlying Core's Sync method,
flushing any buffered log entries. Applications should take care to
call Sync before exiting.`

Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>
2024-02-27 15:10:51 +03:00

766 lines
22 KiB
Go

package consensus
import (
"errors"
"fmt"
"sort"
"sync/atomic"
"time"
"github.com/nspcc-dev/dbft"
"github.com/nspcc-dev/dbft/block"
"github.com/nspcc-dev/dbft/crypto"
"github.com/nspcc-dev/dbft/payload"
"github.com/nspcc-dev/neo-go/pkg/config"
"github.com/nspcc-dev/neo-go/pkg/config/netmode"
coreb "github.com/nspcc-dev/neo-go/pkg/core/block"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/core/mempool"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
"github.com/nspcc-dev/neo-go/pkg/encoding/address"
"github.com/nspcc-dev/neo-go/pkg/io"
npayload "github.com/nspcc-dev/neo-go/pkg/network/payload"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm/emit"
"github.com/nspcc-dev/neo-go/pkg/wallet"
"go.uber.org/zap"
)
// cacheMaxCapacity is the default cache capacity taken
// from C# implementation https://github.com/neo-project/neo/blob/master/neo/Ledger/Blockchain.cs#L64
const cacheMaxCapacity = 100
// defaultTimePerBlock is a period between blocks which is used in Neo.
const defaultTimePerBlock = 15 * time.Second
// Number of nanoseconds in millisecond.
const nsInMs = 1000000
// Ledger is the interface to Blockchain sufficient for Service.
type Ledger interface {
ApplyPolicyToTxSet([]*transaction.Transaction) []*transaction.Transaction
GetConfig() config.Blockchain
GetMemPool() *mempool.Pool
GetNextBlockValidators() ([]*keys.PublicKey, error)
GetStateRoot(height uint32) (*state.MPTRoot, error)
GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
ComputeNextBlockValidators() []*keys.PublicKey
PoolTx(t *transaction.Transaction, pools ...*mempool.Pool) error
SubscribeForBlocks(ch chan *coreb.Block)
UnsubscribeFromBlocks(ch chan *coreb.Block)
GetBaseExecFee() int64
CalculateAttributesFee(tx *transaction.Transaction) int64
interop.Ledger
mempool.Feer
}
// BlockQueuer is an interface to the block queue manager sufficient for Service.
type BlockQueuer interface {
PutBlock(block *coreb.Block) error
}
// Service represents a consensus instance.
type Service interface {
// Name returns service name.
Name() string
// Start initializes dBFT and starts event loop for consensus service.
// It must be called only when the sufficient amount of peers are connected.
// The service only starts once, subsequent calls to Start are no-op.
Start()
// Shutdown stops dBFT event loop. It can only be called once, subsequent calls
// to Shutdown on the same instance are no-op. The instance that was stopped can
// not be started again by calling Start (use a new instance if needed).
Shutdown()
// OnPayload is a callback to notify the Service about a newly received payload.
OnPayload(p *npayload.Extensible) error
// OnTransaction is a callback to notify the Service about a newly received transaction.
OnTransaction(tx *transaction.Transaction)
}
type service struct {
Config
log *zap.Logger
// txx is a fifo cache which stores miner transactions.
txx *relayCache
dbft *dbft.DBFT
// messages and transactions are channels needed to process
// everything in single thread.
messages chan Payload
transactions chan *transaction.Transaction
// blockEvents is used to pass a new block event to the consensus
// process. It has a tiny buffer in order to avoid Blockchain blocking
// on block addition under the high load.
blockEvents chan *coreb.Block
lastProposal []util.Uint256
wallet *wallet.Wallet
// started is a flag set with Start method that runs an event handling
// goroutine.
started atomic.Bool
quit chan struct{}
finished chan struct{}
// lastTimestamp contains timestamp for the last processed block.
// We can't rely on timestamp from dbft context because it is changed
// before the block is accepted. So, in case of change view, it will contain
// an updated value.
lastTimestamp uint64
}
// Config is a configuration for consensus services.
type Config struct {
// Logger is a logger instance.
Logger *zap.Logger
// Broadcast is a callback which is called to notify the server
// about a new consensus payload to be sent.
Broadcast func(p *npayload.Extensible)
// Chain is a Ledger instance.
Chain Ledger
// BlockQueue is a BlockQueuer instance.
BlockQueue BlockQueuer
// ProtocolConfiguration contains protocol settings.
ProtocolConfiguration config.ProtocolConfiguration
// RequestTx is a callback to which will be called
// when a node lacks transactions present in the block.
RequestTx func(h ...util.Uint256)
// StopTxFlow is a callback that is called after the consensus
// process stops accepting incoming transactions.
StopTxFlow func()
// TimePerBlock is minimal time that should pass before the next block is accepted.
TimePerBlock time.Duration
// Wallet is a local-node wallet configuration. If the path is empty, then
// no wallet will be initialized and the service will be in watch-only mode.
Wallet config.Wallet
}
// NewService returns a new consensus.Service instance.
func NewService(cfg Config) (Service, error) {
if cfg.TimePerBlock <= 0 {
cfg.TimePerBlock = defaultTimePerBlock
}
if cfg.Logger == nil {
return nil, errors.New("empty logger")
}
srv := &service{
Config: cfg,
log: cfg.Logger,
txx: newFIFOCache(cacheMaxCapacity),
messages: make(chan Payload, 100),
transactions: make(chan *transaction.Transaction, 100),
blockEvents: make(chan *coreb.Block, 1),
quit: make(chan struct{}),
finished: make(chan struct{}),
}
var err error
if len(cfg.Wallet.Path) > 0 {
if srv.wallet, err = wallet.NewWalletFromFile(cfg.Wallet.Path); err != nil {
return nil, err
}
// Check that the wallet password is correct for at least one account.
var ok bool
for _, acc := range srv.wallet.Accounts {
err := acc.Decrypt(srv.Config.Wallet.Password, srv.wallet.Scrypt)
if err == nil {
ok = true
break
}
}
if !ok {
return nil, errors.New("no account with provided password was found")
}
}
srv.dbft = dbft.New(
dbft.WithLogger(srv.log),
dbft.WithSecondsPerBlock(cfg.TimePerBlock),
dbft.WithGetKeyPair(srv.getKeyPair),
dbft.WithRequestTx(cfg.RequestTx),
dbft.WithStopTxFlow(cfg.StopTxFlow),
dbft.WithGetTx(srv.getTx),
dbft.WithGetVerified(srv.getVerifiedTx),
dbft.WithBroadcast(srv.broadcast),
dbft.WithProcessBlock(srv.processBlock),
dbft.WithVerifyBlock(srv.verifyBlock),
dbft.WithGetBlock(srv.getBlock),
dbft.WithWatchOnly(func() bool { return false }),
dbft.WithNewBlockFromContext(srv.newBlockFromContext),
dbft.WithCurrentHeight(cfg.Chain.BlockHeight),
dbft.WithCurrentBlockHash(cfg.Chain.CurrentBlockHash),
dbft.WithGetValidators(srv.getValidators),
dbft.WithGetConsensusAddress(srv.getConsensusAddress),
dbft.WithNewConsensusPayload(srv.newPayload),
dbft.WithNewPrepareRequest(srv.newPrepareRequest),
dbft.WithNewPrepareResponse(func() payload.PrepareResponse { return new(prepareResponse) }),
dbft.WithNewChangeView(func() payload.ChangeView { return new(changeView) }),
dbft.WithNewCommit(func() payload.Commit { return new(commit) }),
dbft.WithNewRecoveryRequest(func() payload.RecoveryRequest { return new(recoveryRequest) }),
dbft.WithNewRecoveryMessage(func() payload.RecoveryMessage {
return &recoveryMessage{stateRootEnabled: srv.ProtocolConfiguration.StateRootInHeader}
}),
dbft.WithVerifyPrepareRequest(srv.verifyRequest),
dbft.WithVerifyPrepareResponse(func(_ payload.ConsensusPayload) error { return nil }),
)
if srv.dbft == nil {
return nil, errors.New("can't initialize dBFT")
}
return srv, nil
}
var (
_ block.Transaction = (*transaction.Transaction)(nil)
_ block.Block = (*neoBlock)(nil)
)
// NewPayload creates a new consensus payload for the provided network.
func NewPayload(m netmode.Magic, stateRootEnabled bool) *Payload {
return &Payload{
Extensible: npayload.Extensible{
Category: npayload.ConsensusCategory,
},
message: message{
stateRootEnabled: stateRootEnabled,
},
network: m,
}
}
func (s *service) newPayload(c *dbft.Context, t payload.MessageType, msg any) payload.ConsensusPayload {
cp := NewPayload(s.ProtocolConfiguration.Magic, s.ProtocolConfiguration.StateRootInHeader)
cp.SetHeight(c.BlockIndex)
cp.SetValidatorIndex(uint16(c.MyIndex))
cp.SetViewNumber(c.ViewNumber)
cp.SetType(t)
if pr, ok := msg.(*prepareRequest); ok {
pr.SetPrevHash(s.dbft.PrevHash)
pr.SetVersion(s.dbft.Version)
}
cp.SetPayload(msg)
cp.Extensible.ValidBlockStart = 0
cp.Extensible.ValidBlockEnd = c.BlockIndex
cp.Extensible.Sender = c.Validators[c.MyIndex].(*publicKey).GetScriptHash()
return cp
}
func (s *service) newPrepareRequest() payload.PrepareRequest {
r := new(prepareRequest)
if s.ProtocolConfiguration.StateRootInHeader {
r.stateRootEnabled = true
if sr, err := s.Chain.GetStateRoot(s.dbft.BlockIndex - 1); err == nil {
r.stateRoot = sr.Root
} else {
panic(err)
}
}
return r
}
// Name returns service name.
func (s *service) Name() string {
return "consensus"
}
func (s *service) Start() {
if s.started.CompareAndSwap(false, true) {
s.log.Info("starting consensus service")
b, _ := s.Chain.GetBlock(s.Chain.CurrentBlockHash()) // Can't fail, we have some current block!
s.lastTimestamp = b.Timestamp
s.dbft.Start(s.lastTimestamp * nsInMs)
go s.eventLoop()
}
}
// Shutdown implements the Service interface.
func (s *service) Shutdown() {
if s.started.CompareAndSwap(true, false) {
s.log.Info("stopping consensus service")
close(s.quit)
<-s.finished
if s.wallet != nil {
s.wallet.Close()
}
}
_ = s.log.Sync()
}
func (s *service) eventLoop() {
s.Chain.SubscribeForBlocks(s.blockEvents)
// Manually sync up with potentially missed fresh blocks that may be added by blockchain
// before the subscription.
b, _ := s.Chain.GetBlock(s.Chain.CurrentBlockHash()) // Can't fail, we have some current block!
if b.Timestamp >= s.lastTimestamp {
s.handleChainBlock(b)
}
events:
for {
select {
case <-s.quit:
s.dbft.Timer.Stop()
s.Chain.UnsubscribeFromBlocks(s.blockEvents)
break events
case <-s.dbft.Timer.C():
hv := s.dbft.Timer.HV()
s.log.Debug("timer fired",
zap.Uint32("height", hv.Height),
zap.Uint("view", uint(hv.View)))
s.dbft.OnTimeout(hv)
case msg := <-s.messages:
fields := []zap.Field{
zap.Uint8("from", msg.message.ValidatorIndex),
zap.Stringer("type", msg.Type()),
}
if msg.Type() == payload.RecoveryMessageType {
rec := msg.GetRecoveryMessage().(*recoveryMessage)
if rec.preparationHash == nil {
req := rec.GetPrepareRequest(&msg, s.dbft.Validators, uint16(s.dbft.PrimaryIndex))
if req != nil {
h := req.Hash()
rec.preparationHash = &h
}
}
fields = append(fields,
zap.Int("#preparation", len(rec.preparationPayloads)),
zap.Int("#commit", len(rec.commitPayloads)),
zap.Int("#changeview", len(rec.changeViewPayloads)),
zap.Bool("#request", rec.prepareRequest != nil),
zap.Bool("#hash", rec.preparationHash != nil))
}
s.log.Debug("received message", fields...)
s.dbft.OnReceive(&msg)
case tx := <-s.transactions:
s.dbft.OnTransaction(tx)
case b := <-s.blockEvents:
s.handleChainBlock(b)
}
// Always process block event if there is any, we can add one above or external
// services can add several blocks during message processing.
var latestBlock *coreb.Block
syncLoop:
for {
select {
case latestBlock = <-s.blockEvents:
default:
break syncLoop
}
}
if latestBlock != nil {
s.handleChainBlock(latestBlock)
}
}
drainLoop:
for {
select {
case <-s.messages:
case <-s.transactions:
case <-s.blockEvents:
default:
break drainLoop
}
}
close(s.messages)
close(s.transactions)
close(s.blockEvents)
close(s.finished)
}
func (s *service) handleChainBlock(b *coreb.Block) {
// We can get our own block here, so check for index.
if b.Index >= s.dbft.BlockIndex {
s.log.Debug("new block in the chain",
zap.Uint32("dbft index", s.dbft.BlockIndex),
zap.Uint32("chain index", s.Chain.BlockHeight()))
s.postBlock(b)
s.dbft.InitializeConsensus(0, b.Timestamp*nsInMs)
}
}
func (s *service) validatePayload(p *Payload) bool {
validators := s.getValidators()
if int(p.message.ValidatorIndex) >= len(validators) {
return false
}
pub := validators[p.message.ValidatorIndex]
h := pub.(*publicKey).GetScriptHash()
return p.Sender == h
}
func (s *service) getKeyPair(pubs []crypto.PublicKey) (int, crypto.PrivateKey, crypto.PublicKey) {
if s.wallet != nil {
for i := range pubs {
sh := pubs[i].(*publicKey).GetScriptHash()
acc := s.wallet.GetAccount(sh)
if acc == nil {
continue
}
if !acc.CanSign() {
err := acc.Decrypt(s.Config.Wallet.Password, s.wallet.Scrypt)
if err != nil {
s.log.Fatal("can't unlock account", zap.String("address", address.Uint160ToString(sh)))
break
}
}
return i, &privateKey{PrivateKey: acc.PrivateKey()}, &publicKey{PublicKey: acc.PublicKey()}
}
}
return -1, nil, nil
}
func (s *service) payloadFromExtensible(ep *npayload.Extensible) *Payload {
return &Payload{
Extensible: *ep,
message: message{
stateRootEnabled: s.ProtocolConfiguration.StateRootInHeader,
},
}
}
// OnPayload handles Payload receive.
func (s *service) OnPayload(cp *npayload.Extensible) error {
log := s.log.With(zap.Stringer("hash", cp.Hash()))
p := s.payloadFromExtensible(cp)
// decode payload data into message
if err := p.decodeData(); err != nil {
log.Info("can't decode payload data", zap.Error(err))
return nil
}
if !s.validatePayload(p) {
log.Info("can't validate payload")
return nil
}
if s.dbft == nil || !s.started.Load() {
log.Debug("dbft is inactive or not started yet")
return nil
}
s.messages <- *p
return nil
}
func (s *service) OnTransaction(tx *transaction.Transaction) {
if s.dbft != nil && s.started.Load() {
s.transactions <- tx
}
}
func (s *service) broadcast(p payload.ConsensusPayload) {
if err := p.(*Payload).Sign(s.dbft.Priv.(*privateKey)); err != nil {
s.log.Warn("can't sign consensus payload", zap.Error(err))
}
ep := &p.(*Payload).Extensible
s.Config.Broadcast(ep)
}
func (s *service) getTx(h util.Uint256) block.Transaction {
if tx := s.txx.Get(h); tx != nil {
return tx.(*transaction.Transaction)
}
tx, _, _ := s.Config.Chain.GetTransaction(h)
// this is needed because in case of absent tx dBFT expects to
// get nil interface, not a nil pointer to any concrete type
if tx != nil {
return tx
}
return nil
}
func (s *service) verifyBlock(b block.Block) bool {
coreb := &b.(*neoBlock).Block
if s.Chain.BlockHeight() >= coreb.Index {
s.log.Warn("proposed block has already outdated")
return false
}
if s.lastTimestamp >= coreb.Timestamp {
s.log.Warn("proposed block has small timestamp",
zap.Uint64("ts", coreb.Timestamp),
zap.Uint64("last", s.lastTimestamp))
return false
}
size := coreb.GetExpectedBlockSize()
if size > int(s.ProtocolConfiguration.MaxBlockSize) {
s.log.Warn("proposed block size exceeds config MaxBlockSize",
zap.Uint32("max size allowed", s.ProtocolConfiguration.MaxBlockSize),
zap.Int("block size", size))
return false
}
var fee int64
var pool = mempool.New(len(coreb.Transactions), 0, false, nil)
var mainPool = s.Chain.GetMemPool()
for _, tx := range coreb.Transactions {
var err error
fee += tx.SystemFee
if mainPool.ContainsKey(tx.Hash()) {
err = pool.Add(tx, s.Chain)
if err == nil {
continue
}
} else {
err = s.Chain.PoolTx(tx, pool)
}
if err != nil {
s.log.Warn("invalid transaction in proposed block",
zap.Stringer("hash", tx.Hash()),
zap.Error(err))
return false
}
if s.Chain.BlockHeight() >= coreb.Index {
s.log.Warn("proposed block has already outdated")
return false
}
}
maxBlockSysFee := s.ProtocolConfiguration.MaxBlockSystemFee
if fee > maxBlockSysFee {
s.log.Warn("proposed block system fee exceeds config MaxBlockSystemFee",
zap.Int("max system fee allowed", int(maxBlockSysFee)),
zap.Int("block system fee", int(fee)))
return false
}
return true
}
var (
errInvalidPrevHash = errors.New("invalid PrevHash")
errInvalidVersion = errors.New("invalid Version")
errInvalidStateRoot = errors.New("state root mismatch")
errInvalidTransactionsCount = errors.New("invalid transactions count")
)
func (s *service) verifyRequest(p payload.ConsensusPayload) error {
req := p.GetPrepareRequest().(*prepareRequest)
if req.prevHash != s.dbft.PrevHash {
return errInvalidPrevHash
}
if req.version != s.dbft.Version {
return errInvalidVersion
}
if s.ProtocolConfiguration.StateRootInHeader {
sr, err := s.Chain.GetStateRoot(s.dbft.BlockIndex - 1)
if err != nil {
return err
} else if sr.Root != req.stateRoot {
return fmt.Errorf("%w: %s != %s", errInvalidStateRoot, sr.Root, req.stateRoot)
}
}
if len(req.TransactionHashes()) > int(s.ProtocolConfiguration.MaxTransactionsPerBlock) {
return fmt.Errorf("%w: max = %d, got %d", errInvalidTransactionsCount, s.ProtocolConfiguration.MaxTransactionsPerBlock, len(req.TransactionHashes()))
}
// Save lastProposal for getVerified().
s.lastProposal = req.transactionHashes
return nil
}
func (s *service) processBlock(b block.Block) {
bb := &b.(*neoBlock).Block
bb.Script = *(s.getBlockWitness(bb))
if err := s.BlockQueue.PutBlock(bb); err != nil {
// The block might already be added via the regular network
// interaction.
if _, errget := s.Chain.GetBlock(bb.Hash()); errget != nil {
s.log.Warn("error on enqueue block", zap.Error(err))
}
}
s.postBlock(bb)
}
func (s *service) postBlock(b *coreb.Block) {
if s.lastTimestamp < b.Timestamp {
s.lastTimestamp = b.Timestamp
}
s.lastProposal = nil
}
func (s *service) getBlockWitness(b *coreb.Block) *transaction.Witness {
dctx := s.dbft.Context
pubs := convertKeys(dctx.Validators)
sigs := make(map[*keys.PublicKey][]byte)
for i := range pubs {
if p := dctx.CommitPayloads[i]; p != nil && p.ViewNumber() == dctx.ViewNumber {
sigs[pubs[i]] = p.GetCommit().Signature()
}
}
m := s.dbft.Context.M()
verif, err := smartcontract.CreateMultiSigRedeemScript(m, pubs)
if err != nil {
s.log.Warn("can't create multisig redeem script", zap.Error(err))
return nil
}
sort.Sort(keys.PublicKeys(pubs))
buf := io.NewBufBinWriter()
for i, j := 0, 0; i < len(pubs) && j < m; i++ {
if sig, ok := sigs[pubs[i]]; ok {
emit.Bytes(buf.BinWriter, sig)
j++
}
}
return &transaction.Witness{
InvocationScript: buf.Bytes(),
VerificationScript: verif,
}
}
func (s *service) getBlock(h util.Uint256) block.Block {
b, err := s.Chain.GetBlock(h)
if err != nil {
return nil
}
return &neoBlock{network: s.ProtocolConfiguration.Magic, Block: *b}
}
func (s *service) getVerifiedTx() []block.Transaction {
pool := s.Config.Chain.GetMemPool()
var txx []*transaction.Transaction
if s.dbft.ViewNumber > 0 && len(s.lastProposal) > 0 {
txx = make([]*transaction.Transaction, 0, len(s.lastProposal))
for i := range s.lastProposal {
if tx, ok := pool.TryGetValue(s.lastProposal[i]); ok {
txx = append(txx, tx)
}
}
if len(txx) < len(s.lastProposal)/2 {
txx = pool.GetVerifiedTransactions()
}
} else {
txx = pool.GetVerifiedTransactions()
}
if len(txx) > 0 {
txx = s.Config.Chain.ApplyPolicyToTxSet(txx)
}
res := make([]block.Transaction, len(txx))
for i := range txx {
res[i] = txx[i]
}
return res
}
func (s *service) getValidators(txes ...block.Transaction) []crypto.PublicKey {
var (
pKeys []*keys.PublicKey
err error
)
if txes == nil {
// getValidators with empty args is used by dbft to fill the list of
// block's validators, thus should return validators from the current
// epoch without recalculation.
pKeys, err = s.Chain.GetNextBlockValidators()
}
// getValidators with non-empty args is used by dbft to fill block's
// NextConsensus field, but NeoGo doesn't provide WithGetConsensusAddress
// callback and fills NextConsensus by itself via WithNewBlockFromContext
// callback. Thus, leave pKeys empty if txes != nil.
if err != nil {
s.log.Error("error while trying to get validators", zap.Error(err))
}
pubs := make([]crypto.PublicKey, len(pKeys))
for i := range pKeys {
pubs[i] = &publicKey{PublicKey: pKeys[i]}
}
return pubs
}
func (s *service) getConsensusAddress(validators ...crypto.PublicKey) util.Uint160 {
return util.Uint160{}
}
func convertKeys(validators []crypto.PublicKey) (pubs []*keys.PublicKey) {
pubs = make([]*keys.PublicKey, len(validators))
for i, k := range validators {
pubs[i] = k.(*publicKey).PublicKey
}
return
}
func (s *service) newBlockFromContext(ctx *dbft.Context) block.Block {
block := &neoBlock{network: s.ProtocolConfiguration.Magic}
block.Block.Timestamp = ctx.Timestamp / nsInMs
block.Block.Nonce = ctx.Nonce
block.Block.Index = ctx.BlockIndex
if s.ProtocolConfiguration.StateRootInHeader {
sr, err := s.Chain.GetStateRoot(ctx.BlockIndex - 1)
if err != nil {
s.log.Fatal(fmt.Sprintf("failed to get state root: %s", err.Error()))
}
block.StateRootEnabled = true
block.PrevStateRoot = sr.Root
}
// ComputeNextBlockValidators returns proper set of validators wrt dBFT epochs
// boundary. I.e. for the last block in the dBFT epoch this method returns the
// list of validators recalculated from the latest relevant information about
// NEO votes; in this case list of validators may differ from the one returned
// by GetNextBlockValidators. For the not-last block of dBFT epoch this method
// returns the same list as GetNextBlockValidators. Note, that by this moment
// we must be sure that previous block was successfully persisted to chain
// (i.e. PostPersist was completed for native Neo contract and PostPersist
// execution cache was persisted to s.Chain's DAO), otherwise the wrong
// (outdated, relevant for the previous dBFT epoch) value will be returned.
var validators = s.Chain.ComputeNextBlockValidators()
script, err := smartcontract.CreateDefaultMultiSigRedeemScript(validators)
if err != nil {
s.log.Fatal(fmt.Sprintf("failed to create multisignature script: %s", err.Error()))
}
block.Block.NextConsensus = crypto.Hash160(script)
block.Block.PrevHash = ctx.PrevHash
block.Block.Version = ctx.Version
primaryIndex := byte(ctx.PrimaryIndex)
block.Block.PrimaryIndex = primaryIndex
// it's OK to have ctx.TransactionsHashes == nil here
hashes := make([]util.Uint256, len(ctx.TransactionHashes))
copy(hashes, ctx.TransactionHashes)
block.Block.MerkleRoot = hash.CalcMerkleRoot(hashes)
return block
}