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- // Copyright 2017 The go-ethereum Authors
- // This file is part of the go-ethereum library.
- //
- // The go-ethereum library is free software: you can redistribute it and/or modify
- // it under the terms of the GNU Lesser General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // The go-ethereum library is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU Lesser General Public License for more details.
- //
- // You should have received a copy of the GNU Lesser General Public License
- // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
- // Package clique implements the proof-of-authority consensus engine.
- package clique
- import (
- "bytes"
- "errors"
- "io"
- "math/big"
- "math/rand"
- "sync"
- "time"
- "github.com/ethereum/go-ethereum/accounts"
- "github.com/ethereum/go-ethereum/common"
- "github.com/ethereum/go-ethereum/common/hexutil"
- "github.com/ethereum/go-ethereum/consensus"
- "github.com/ethereum/go-ethereum/consensus/misc"
- "github.com/ethereum/go-ethereum/core/state"
- "github.com/ethereum/go-ethereum/core/types"
- "github.com/ethereum/go-ethereum/crypto"
- "github.com/ethereum/go-ethereum/ethdb"
- "github.com/ethereum/go-ethereum/log"
- "github.com/ethereum/go-ethereum/params"
- "github.com/ethereum/go-ethereum/rlp"
- "github.com/ethereum/go-ethereum/rpc"
- "github.com/ethereum/go-ethereum/trie"
- lru "github.com/hashicorp/golang-lru"
- "golang.org/x/crypto/sha3"
- )
- const (
- checkpointInterval = 1024 // Number of blocks after which to save the vote snapshot to the database
- inmemorySnapshots = 128 // Number of recent vote snapshots to keep in memory
- inmemorySignatures = 4096 // Number of recent block signatures to keep in memory
- wiggleTime = 500 * time.Millisecond // Random delay (per signer) to allow concurrent signers
- )
- // Clique proof-of-authority protocol constants.
- var (
- epochLength = uint64(30000) // Default number of blocks after which to checkpoint and reset the pending votes
- extraVanity = 32 // Fixed number of extra-data prefix bytes reserved for signer vanity
- extraSeal = crypto.SignatureLength // Fixed number of extra-data suffix bytes reserved for signer seal
- nonceAuthVote = hexutil.MustDecode("0xffffffffffffffff") // Magic nonce number to vote on adding a new signer
- nonceDropVote = hexutil.MustDecode("0x0000000000000000") // Magic nonce number to vote on removing a signer.
- uncleHash = types.CalcUncleHash(nil) // Always Keccak256(RLP([])) as uncles are meaningless outside of PoW.
- diffInTurn = big.NewInt(2) // Block difficulty for in-turn signatures
- diffNoTurn = big.NewInt(1) // Block difficulty for out-of-turn signatures
- )
- // Various error messages to mark blocks invalid. These should be private to
- // prevent engine specific errors from being referenced in the remainder of the
- // codebase, inherently breaking if the engine is swapped out. Please put common
- // error types into the consensus package.
- var (
- // errUnknownBlock is returned when the list of signers is requested for a block
- // that is not part of the local blockchain.
- errUnknownBlock = errors.New("unknown block")
- // errInvalidCheckpointBeneficiary is returned if a checkpoint/epoch transition
- // block has a beneficiary set to non-zeroes.
- errInvalidCheckpointBeneficiary = errors.New("beneficiary in checkpoint block non-zero")
- // errInvalidVote is returned if a nonce value is something else that the two
- // allowed constants of 0x00..0 or 0xff..f.
- errInvalidVote = errors.New("vote nonce not 0x00..0 or 0xff..f")
- // errInvalidCheckpointVote is returned if a checkpoint/epoch transition block
- // has a vote nonce set to non-zeroes.
- errInvalidCheckpointVote = errors.New("vote nonce in checkpoint block non-zero")
- // errMissingVanity is returned if a block's extra-data section is shorter than
- // 32 bytes, which is required to store the signer vanity.
- errMissingVanity = errors.New("extra-data 32 byte vanity prefix missing")
- // errMissingSignature is returned if a block's extra-data section doesn't seem
- // to contain a 65 byte secp256k1 signature.
- errMissingSignature = errors.New("extra-data 65 byte signature suffix missing")
- // errExtraSigners is returned if non-checkpoint block contain signer data in
- // their extra-data fields.
- errExtraSigners = errors.New("non-checkpoint block contains extra signer list")
- // errInvalidCheckpointSigners is returned if a checkpoint block contains an
- // invalid list of signers (i.e. non divisible by 20 bytes).
- errInvalidCheckpointSigners = errors.New("invalid signer list on checkpoint block")
- // errMismatchingCheckpointSigners is returned if a checkpoint block contains a
- // list of signers different than the one the local node calculated.
- errMismatchingCheckpointSigners = errors.New("mismatching signer list on checkpoint block")
- // errInvalidMixDigest is returned if a block's mix digest is non-zero.
- errInvalidMixDigest = errors.New("non-zero mix digest")
- // errInvalidUncleHash is returned if a block contains an non-empty uncle list.
- errInvalidUncleHash = errors.New("non empty uncle hash")
- // errInvalidDifficulty is returned if the difficulty of a block neither 1 or 2.
- errInvalidDifficulty = errors.New("invalid difficulty")
- // errWrongDifficulty is returned if the difficulty of a block doesn't match the
- // turn of the signer.
- errWrongDifficulty = errors.New("wrong difficulty")
- // errInvalidTimestamp is returned if the timestamp of a block is lower than
- // the previous block's timestamp + the minimum block period.
- errInvalidTimestamp = errors.New("invalid timestamp")
- // errInvalidVotingChain is returned if an authorization list is attempted to
- // be modified via out-of-range or non-contiguous headers.
- errInvalidVotingChain = errors.New("invalid voting chain")
- // errUnauthorizedSigner is returned if a header is signed by a non-authorized entity.
- errUnauthorizedSigner = errors.New("unauthorized signer")
- // errRecentlySigned is returned if a header is signed by an authorized entity
- // that already signed a header recently, thus is temporarily not allowed to.
- errRecentlySigned = errors.New("recently signed")
- )
- // SignerFn hashes and signs the data to be signed by a backing account.
- type SignerFn func(signer accounts.Account, mimeType string, message []byte) ([]byte, error)
- // ecrecover extracts the Ethereum account address from a signed header.
- func ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
- // If the signature's already cached, return that
- hash := header.Hash()
- if address, known := sigcache.Get(hash); known {
- return address.(common.Address), nil
- }
- // Retrieve the signature from the header extra-data
- if len(header.Extra) < extraSeal {
- return common.Address{}, errMissingSignature
- }
- signature := header.Extra[len(header.Extra)-extraSeal:]
- // Recover the public key and the Ethereum address
- pubkey, err := crypto.Ecrecover(SealHash(header).Bytes(), signature)
- if err != nil {
- return common.Address{}, err
- }
- var signer common.Address
- copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
- sigcache.Add(hash, signer)
- return signer, nil
- }
- // Clique is the proof-of-authority consensus engine proposed to support the
- // Ethereum testnet following the Ropsten attacks.
- type Clique struct {
- config *params.CliqueConfig // Consensus engine configuration parameters
- db ethdb.Database // Database to store and retrieve snapshot checkpoints
- recents *lru.ARCCache // Snapshots for recent block to speed up reorgs
- signatures *lru.ARCCache // Signatures of recent blocks to speed up mining
- proposals map[common.Address]bool // Current list of proposals we are pushing
- signer common.Address // Ethereum address of the signing key
- signFn SignerFn // Signer function to authorize hashes with
- lock sync.RWMutex // Protects the signer fields
- // The fields below are for testing only
- fakeDiff bool // Skip difficulty verifications
- }
- // New creates a Clique proof-of-authority consensus engine with the initial
- // signers set to the ones provided by the user.
- func New(config *params.CliqueConfig, db ethdb.Database) *Clique {
- // Set any missing consensus parameters to their defaults
- conf := *config
- if conf.Epoch == 0 {
- conf.Epoch = epochLength
- }
- // Allocate the snapshot caches and create the engine
- recents, _ := lru.NewARC(inmemorySnapshots)
- signatures, _ := lru.NewARC(inmemorySignatures)
- return &Clique{
- config: &conf,
- db: db,
- recents: recents,
- signatures: signatures,
- proposals: make(map[common.Address]bool),
- }
- }
- // Author implements consensus.Engine, returning the Ethereum address recovered
- // from the signature in the header's extra-data section.
- func (c *Clique) Author(header *types.Header) (common.Address, error) {
- return ecrecover(header, c.signatures)
- }
- // VerifyHeader checks whether a header conforms to the consensus rules.
- func (c *Clique) VerifyHeader(chain consensus.ChainHeaderReader, header *types.Header, seal bool) error {
- return c.verifyHeader(chain, header, nil)
- }
- // VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers. The
- // method returns a quit channel to abort the operations and a results channel to
- // retrieve the async verifications (the order is that of the input slice).
- func (c *Clique) VerifyHeaders(chain consensus.ChainHeaderReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error) {
- abort := make(chan struct{})
- results := make(chan error, len(headers))
- go func() {
- for i, header := range headers {
- err := c.verifyHeader(chain, header, headers[:i])
- select {
- case <-abort:
- return
- case results <- err:
- }
- }
- }()
- return abort, results
- }
- // verifyHeader checks whether a header conforms to the consensus rules.The
- // caller may optionally pass in a batch of parents (ascending order) to avoid
- // looking those up from the database. This is useful for concurrently verifying
- // a batch of new headers.
- func (c *Clique) verifyHeader(chain consensus.ChainHeaderReader, header *types.Header, parents []*types.Header) error {
- if header.Number == nil {
- return errUnknownBlock
- }
- number := header.Number.Uint64()
- // Don't waste time checking blocks from the future (adjusting for allowed threshold)
- adjustedTimeNow := time.Now().Add(time.Duration(c.config.AllowedFutureBlockTime) * time.Second).Unix()
- if header.Time > uint64(adjustedTimeNow) {
- return consensus.ErrFutureBlock
- }
- // Checkpoint blocks need to enforce zero beneficiary
- checkpoint := (number % c.config.Epoch) == 0
- if checkpoint && header.Coinbase != (common.Address{}) {
- return errInvalidCheckpointBeneficiary
- }
- // Nonces must be 0x00..0 or 0xff..f, zeroes enforced on checkpoints
- if !bytes.Equal(header.Nonce[:], nonceAuthVote) && !bytes.Equal(header.Nonce[:], nonceDropVote) {
- return errInvalidVote
- }
- if checkpoint && !bytes.Equal(header.Nonce[:], nonceDropVote) {
- return errInvalidCheckpointVote
- }
- // Check that the extra-data contains both the vanity and signature
- if len(header.Extra) < extraVanity {
- return errMissingVanity
- }
- if len(header.Extra) < extraVanity+extraSeal {
- return errMissingSignature
- }
- // Ensure that the extra-data contains a signer list on checkpoint, but none otherwise
- signersBytes := len(header.Extra) - extraVanity - extraSeal
- if !checkpoint && signersBytes != 0 {
- return errExtraSigners
- }
- if checkpoint && signersBytes%common.AddressLength != 0 {
- return errInvalidCheckpointSigners
- }
- // Ensure that the mix digest is zero as we don't have fork protection currently
- if header.MixDigest != (common.Hash{}) {
- return errInvalidMixDigest
- }
- // Ensure that the block doesn't contain any uncles which are meaningless in PoA
- if header.UncleHash != uncleHash {
- return errInvalidUncleHash
- }
- // Ensure that the block's difficulty is meaningful (may not be correct at this point)
- if number > 0 {
- if header.Difficulty == nil || (header.Difficulty.Cmp(diffInTurn) != 0 && header.Difficulty.Cmp(diffNoTurn) != 0) {
- return errInvalidDifficulty
- }
- }
- // If all checks passed, validate any special fields for hard forks
- if err := misc.VerifyForkHashes(chain.Config(), header, false); err != nil {
- return err
- }
- // All basic checks passed, verify cascading fields
- return c.verifyCascadingFields(chain, header, parents)
- }
- // verifyCascadingFields verifies all the header fields that are not standalone,
- // rather depend on a batch of previous headers. The caller may optionally pass
- // in a batch of parents (ascending order) to avoid looking those up from the
- // database. This is useful for concurrently verifying a batch of new headers.
- func (c *Clique) verifyCascadingFields(chain consensus.ChainHeaderReader, header *types.Header, parents []*types.Header) error {
- // The genesis block is the always valid dead-end
- number := header.Number.Uint64()
- if number == 0 {
- return nil
- }
- // Ensure that the block's timestamp isn't too close to its parent
- var parent *types.Header
- if len(parents) > 0 {
- parent = parents[len(parents)-1]
- } else {
- parent = chain.GetHeader(header.ParentHash, number-1)
- }
- if parent == nil || parent.Number.Uint64() != number-1 || parent.Hash() != header.ParentHash {
- return consensus.ErrUnknownAncestor
- }
- if parent.Time+c.config.Period > header.Time {
- return errInvalidTimestamp
- }
- // Retrieve the snapshot needed to verify this header and cache it
- snap, err := c.snapshot(chain, number-1, header.ParentHash, parents)
- if err != nil {
- return err
- }
- // If the block is a checkpoint block, verify the signer list
- if number%c.config.Epoch == 0 {
- signers := make([]byte, len(snap.Signers)*common.AddressLength)
- for i, signer := range snap.signers() {
- copy(signers[i*common.AddressLength:], signer[:])
- }
- extraSuffix := len(header.Extra) - extraSeal
- if !bytes.Equal(header.Extra[extraVanity:extraSuffix], signers) {
- return errMismatchingCheckpointSigners
- }
- }
- // All basic checks passed, verify the seal and return
- return c.verifySeal(chain, header, parents)
- }
- // snapshot retrieves the authorization snapshot at a given point in time.
- func (c *Clique) snapshot(chain consensus.ChainHeaderReader, number uint64, hash common.Hash, parents []*types.Header) (*Snapshot, error) {
- // Search for a snapshot in memory or on disk for checkpoints
- var (
- headers []*types.Header
- snap *Snapshot
- )
- for snap == nil {
- // If an in-memory snapshot was found, use that
- if s, ok := c.recents.Get(hash); ok {
- snap = s.(*Snapshot)
- break
- }
- // If an on-disk checkpoint snapshot can be found, use that
- if number%checkpointInterval == 0 {
- if s, err := loadSnapshot(c.config, c.signatures, c.db, hash); err == nil {
- log.Trace("Loaded voting snapshot from disk", "number", number, "hash", hash)
- snap = s
- break
- }
- }
- // If we're at the genesis, snapshot the initial state. Alternatively if we're
- // at a checkpoint block without a parent (light client CHT), or we have piled
- // up more headers than allowed to be reorged (chain reinit from a freezer),
- // consider the checkpoint trusted and snapshot it.
- if number == 0 || (number%c.config.Epoch == 0 && (len(headers) > params.GetImmutabilityThreshold() || chain.GetHeaderByNumber(number-1) == nil)) {
- checkpoint := chain.GetHeaderByNumber(number)
- if checkpoint != nil {
- hash := checkpoint.Hash()
- signers := make([]common.Address, (len(checkpoint.Extra)-extraVanity-extraSeal)/common.AddressLength)
- for i := 0; i < len(signers); i++ {
- copy(signers[i][:], checkpoint.Extra[extraVanity+i*common.AddressLength:])
- }
- snap = newSnapshot(c.config, c.signatures, number, hash, signers)
- if err := snap.store(c.db); err != nil {
- return nil, err
- }
- log.Info("Stored checkpoint snapshot to disk", "number", number, "hash", hash)
- break
- }
- }
- // No snapshot for this header, gather the header and move backward
- var header *types.Header
- if len(parents) > 0 {
- // If we have explicit parents, pick from there (enforced)
- header = parents[len(parents)-1]
- if header.Hash() != hash || header.Number.Uint64() != number {
- return nil, consensus.ErrUnknownAncestor
- }
- parents = parents[:len(parents)-1]
- } else {
- // No explicit parents (or no more left), reach out to the database
- header = chain.GetHeader(hash, number)
- if header == nil {
- return nil, consensus.ErrUnknownAncestor
- }
- }
- headers = append(headers, header)
- number, hash = number-1, header.ParentHash
- }
- // Previous snapshot found, apply any pending headers on top of it
- for i := 0; i < len(headers)/2; i++ {
- headers[i], headers[len(headers)-1-i] = headers[len(headers)-1-i], headers[i]
- }
- snap, err := snap.apply(headers)
- if err != nil {
- return nil, err
- }
- c.recents.Add(snap.Hash, snap)
- // If we've generated a new checkpoint snapshot, save to disk
- if snap.Number%checkpointInterval == 0 && len(headers) > 0 {
- if err = snap.store(c.db); err != nil {
- return nil, err
- }
- log.Trace("Stored voting snapshot to disk", "number", snap.Number, "hash", snap.Hash)
- }
- return snap, err
- }
- // VerifyUncles implements consensus.Engine, always returning an error for any
- // uncles as this consensus mechanism doesn't permit uncles.
- func (c *Clique) VerifyUncles(chain consensus.ChainReader, block *types.Block) error {
- if len(block.Uncles()) > 0 {
- return errors.New("uncles not allowed")
- }
- return nil
- }
- // verifySeal checks whether the signature contained in the header satisfies the
- // consensus protocol requirements. The method accepts an optional list of parent
- // headers that aren't yet part of the local blockchain to generate the snapshots
- // from.
- func (c *Clique) verifySeal(chain consensus.ChainHeaderReader, header *types.Header, parents []*types.Header) error {
- // Verifying the genesis block is not supported
- number := header.Number.Uint64()
- if number == 0 {
- return errUnknownBlock
- }
- // Retrieve the snapshot needed to verify this header and cache it
- snap, err := c.snapshot(chain, number-1, header.ParentHash, parents)
- if err != nil {
- return err
- }
- // Resolve the authorization key and check against signers
- signer, err := ecrecover(header, c.signatures)
- if err != nil {
- return err
- }
- if _, ok := snap.Signers[signer]; !ok {
- return errUnauthorizedSigner
- }
- for seen, recent := range snap.Recents {
- if recent == signer {
- // Signer is among recents, only fail if the current block doesn't shift it out
- if limit := uint64(len(snap.Signers)/2 + 1); seen > number-limit {
- return errRecentlySigned
- }
- }
- }
- // Ensure that the difficulty corresponds to the turn-ness of the signer
- if !c.fakeDiff {
- inturn := snap.inturn(header.Number.Uint64(), signer)
- if inturn && header.Difficulty.Cmp(diffInTurn) != 0 {
- return errWrongDifficulty
- }
- if !inturn && header.Difficulty.Cmp(diffNoTurn) != 0 {
- return errWrongDifficulty
- }
- }
- return nil
- }
- // Prepare implements consensus.Engine, preparing all the consensus fields of the
- // header for running the transactions on top.
- func (c *Clique) Prepare(chain consensus.ChainHeaderReader, header *types.Header) error {
- // If the block isn't a checkpoint, cast a random vote (good enough for now)
- header.Coinbase = common.Address{}
- header.Nonce = types.BlockNonce{}
- number := header.Number.Uint64()
- // Assemble the voting snapshot to check which votes make sense
- snap, err := c.snapshot(chain, number-1, header.ParentHash, nil)
- if err != nil {
- return err
- }
- if number%c.config.Epoch != 0 {
- c.lock.RLock()
- // Gather all the proposals that make sense voting on
- addresses := make([]common.Address, 0, len(c.proposals))
- for address, authorize := range c.proposals {
- if snap.validVote(address, authorize) {
- addresses = append(addresses, address)
- }
- }
- // If there's pending proposals, cast a vote on them
- if len(addresses) > 0 {
- header.Coinbase = addresses[rand.Intn(len(addresses))]
- if c.proposals[header.Coinbase] {
- copy(header.Nonce[:], nonceAuthVote)
- } else {
- copy(header.Nonce[:], nonceDropVote)
- }
- }
- c.lock.RUnlock()
- }
- // Set the correct difficulty
- header.Difficulty = calcDifficulty(snap, c.signer)
- // Ensure the extra data has all its components
- if len(header.Extra) < extraVanity {
- header.Extra = append(header.Extra, bytes.Repeat([]byte{0x00}, extraVanity-len(header.Extra))...)
- }
- header.Extra = header.Extra[:extraVanity]
- if number%c.config.Epoch == 0 {
- for _, signer := range snap.signers() {
- header.Extra = append(header.Extra, signer[:]...)
- }
- }
- header.Extra = append(header.Extra, make([]byte, extraSeal)...)
- // Mix digest is reserved for now, set to empty
- header.MixDigest = common.Hash{}
- // Ensure the timestamp has the correct delay
- parent := chain.GetHeader(header.ParentHash, number-1)
- if parent == nil {
- return consensus.ErrUnknownAncestor
- }
- header.Time = parent.Time + c.config.Period
- if header.Time < uint64(time.Now().Unix()) {
- header.Time = uint64(time.Now().Unix())
- }
- return nil
- }
- // Finalize implements consensus.Engine, ensuring no uncles are set, nor block
- // rewards given.
- func (c *Clique) Finalize(chain consensus.ChainHeaderReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header) {
- // No block rewards in PoA, so the state remains as is and uncles are dropped
- header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
- header.UncleHash = types.CalcUncleHash(nil)
- }
- // FinalizeAndAssemble implements consensus.Engine, ensuring no uncles are set,
- // nor block rewards given, and returns the final block.
- func (c *Clique) FinalizeAndAssemble(chain consensus.ChainHeaderReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error) {
- // Finalize block
- c.Finalize(chain, header, state, txs, uncles)
- // Assemble and return the final block for sealing
- return types.NewBlock(header, txs, nil, receipts, trie.NewStackTrie(nil)), nil
- }
- // Authorize injects a private key into the consensus engine to mint new blocks
- // with.
- func (c *Clique) Authorize(signer common.Address, signFn SignerFn) {
- c.lock.Lock()
- defer c.lock.Unlock()
- c.signer = signer
- c.signFn = signFn
- }
- // Seal implements consensus.Engine, attempting to create a sealed block using
- // the local signing credentials.
- func (c *Clique) Seal(chain consensus.ChainHeaderReader, block *types.Block, results chan<- *types.Block, stop <-chan struct{}) error {
- header := block.Header()
- // Sealing the genesis block is not supported
- number := header.Number.Uint64()
- if number == 0 {
- return errUnknownBlock
- }
- // For 0-period chains, refuse to seal empty blocks (no reward but would spin sealing)
- if c.config.Period == 0 && len(block.Transactions()) == 0 {
- log.Info("Sealing paused, waiting for transactions")
- return nil
- }
- // Don't hold the signer fields for the entire sealing procedure
- c.lock.RLock()
- signer, signFn := c.signer, c.signFn
- c.lock.RUnlock()
- // Bail out if we're unauthorized to sign a block
- snap, err := c.snapshot(chain, number-1, header.ParentHash, nil)
- if err != nil {
- return err
- }
- if _, authorized := snap.Signers[signer]; !authorized {
- return errUnauthorizedSigner
- }
- // If we're amongst the recent signers, wait for the next block
- for seen, recent := range snap.Recents {
- if recent == signer {
- // Signer is among recents, only wait if the current block doesn't shift it out
- if limit := uint64(len(snap.Signers)/2 + 1); number < limit || seen > number-limit {
- log.Info("Signed recently, must wait for others")
- return nil
- }
- }
- }
- // Sweet, the protocol permits us to sign the block, wait for our time
- delay := time.Unix(int64(header.Time), 0).Sub(time.Now()) // nolint: gosimple
- if header.Difficulty.Cmp(diffNoTurn) == 0 {
- // It's not our turn explicitly to sign, delay it a bit
- wiggle := time.Duration(len(snap.Signers)/2+1) * wiggleTime
- delay += time.Duration(rand.Int63n(int64(wiggle)))
- log.Trace("Out-of-turn signing requested", "wiggle", common.PrettyDuration(wiggle))
- }
- // Sign all the things!
- sighash, err := signFn(accounts.Account{Address: signer}, accounts.MimetypeClique, CliqueRLP(header))
- if err != nil {
- return err
- }
- copy(header.Extra[len(header.Extra)-extraSeal:], sighash)
- // Wait until sealing is terminated or delay timeout.
- log.Trace("Waiting for slot to sign and propagate", "delay", common.PrettyDuration(delay))
- go func() {
- select {
- case <-stop:
- return
- case <-time.After(delay):
- }
- select {
- case results <- block.WithSeal(header):
- default:
- log.Warn("Sealing result is not read by miner", "sealhash", SealHash(header))
- }
- }()
- return nil
- }
- // CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
- // that a new block should have:
- // * DIFF_NOTURN(2) if BLOCK_NUMBER % SIGNER_COUNT != SIGNER_INDEX
- // * DIFF_INTURN(1) if BLOCK_NUMBER % SIGNER_COUNT == SIGNER_INDEX
- func (c *Clique) CalcDifficulty(chain consensus.ChainHeaderReader, time uint64, parent *types.Header) *big.Int {
- snap, err := c.snapshot(chain, parent.Number.Uint64(), parent.Hash(), nil)
- if err != nil {
- return nil
- }
- return calcDifficulty(snap, c.signer)
- }
- func calcDifficulty(snap *Snapshot, signer common.Address) *big.Int {
- if snap.inturn(snap.Number+1, signer) {
- return new(big.Int).Set(diffInTurn)
- }
- return new(big.Int).Set(diffNoTurn)
- }
- // SealHash returns the hash of a block prior to it being sealed.
- func (c *Clique) SealHash(header *types.Header) common.Hash {
- return SealHash(header)
- }
- // Close implements consensus.Engine. It's a noop for clique as there are no background threads.
- func (c *Clique) Close() error {
- return nil
- }
- // APIs implements consensus.Engine, returning the user facing RPC API to allow
- // controlling the signer voting.
- func (c *Clique) APIs(chain consensus.ChainHeaderReader) []rpc.API {
- return []rpc.API{{
- Namespace: "clique",
- Version: "1.0",
- Service: &API{chain: chain, clique: c},
- Public: false,
- }}
- }
- // SealHash returns the hash of a block prior to it being sealed.
- func SealHash(header *types.Header) (hash common.Hash) {
- hasher := sha3.NewLegacyKeccak256()
- encodeSigHeader(hasher, header)
- hasher.Sum(hash[:0])
- return hash
- }
- // CliqueRLP returns the rlp bytes which needs to be signed for the proof-of-authority
- // sealing. The RLP to sign consists of the entire header apart from the 65 byte signature
- // contained at the end of the extra data.
- //
- // Note, the method requires the extra data to be at least 65 bytes, otherwise it
- // panics. This is done to avoid accidentally using both forms (signature present
- // or not), which could be abused to produce different hashes for the same header.
- func CliqueRLP(header *types.Header) []byte {
- b := new(bytes.Buffer)
- encodeSigHeader(b, header)
- return b.Bytes()
- }
- func encodeSigHeader(w io.Writer, header *types.Header) {
- err := rlp.Encode(w, []interface{}{
- header.ParentHash,
- header.UncleHash,
- header.Coinbase,
- header.Root,
- header.TxHash,
- header.ReceiptHash,
- header.Bloom,
- header.Difficulty,
- header.Number,
- header.GasLimit,
- header.GasUsed,
- header.Time,
- header.Extra[:len(header.Extra)-crypto.SignatureLength], // Yes, this will panic if extra is too short
- header.MixDigest,
- header.Nonce,
- })
- if err != nil {
- panic("can't encode: " + err.Error())
- }
- }
- // Protocol implements consensus.Engine.Protocol
- func (c *Clique) Protocol() consensus.Protocol {
- return consensus.CliqueProtocol
- }
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