// 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" "fmt" "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" lru "github.com/ethereum/go-ethereum/common/lru" "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" "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 *sigLRU) (common.Address, error) { // If the signature's already cached, return that hash := header.Hash() if address, known := sigcache.Get(hash); known { return 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.Cache[common.Hash, *Snapshot] // Snapshots for recent block to speed up reorgs signatures *sigLRU // 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 and proposals 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.NewCache[common.Hash, *Snapshot](inmemorySnapshots) signatures := lru.NewCache[common.Hash, common.Address](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) 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) (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 if header.Time > uint64(time.Now().Unix()) { 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 } } // Verify that the gas limit is <= 2^63-1 if header.GasLimit > params.MaxGasLimit { return fmt.Errorf("invalid gasLimit: have %v, max %v", header.GasLimit, params.MaxGasLimit) } if chain.Config().IsShanghai(header.Number, header.Time) { return errors.New("clique does not support shanghai fork") } if chain.Config().IsCancun(header.Number, header.Time) { return errors.New("clique does not support cancun fork") } // 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 } // Verify that the gasUsed is <= gasLimit if header.GasUsed > header.GasLimit { return fmt.Errorf("invalid gasUsed: have %d, gasLimit %d", header.GasUsed, header.GasLimit) } if !chain.Config().IsLondon(header.Number) { // Verify BaseFee not present before EIP-1559 fork. if header.BaseFee != nil { return fmt.Errorf("invalid baseFee before fork: have %d, want <nil>", header.BaseFee) } if err := misc.VerifyGaslimit(parent.GasLimit, header.GasLimit); err != nil { return err } } else if err := misc.VerifyEIP1559Header(chain.Config(), parent, header); err != nil { // Verify the header's EIP-1559 attributes. return err } // 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(snap, 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 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.FullImmutabilityThreshold || 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(snap *Snapshot, header *types.Header, parents []*types.Header) error { // Verifying the genesis block is not supported number := header.Number.Uint64() if number == 0 { return errUnknownBlock } // 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 } c.lock.RLock() if number%c.config.Epoch != 0 { // 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) } } } // Copy signer protected by mutex to avoid race condition signer := c.signer c.lock.RUnlock() // Set the correct difficulty header.Difficulty = calcDifficulty(snap, 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. There is no post-transaction // consensus rules in clique, do nothing here. func (c *Clique) Finalize(chain consensus.ChainHeaderReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header, withdrawals []*types.Withdrawal) { // No block rewards in PoA, so the state remains as is } // 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, withdrawals []*types.Withdrawal) (*types.Block, error) { if len(withdrawals) > 0 { return nil, errors.New("clique does not support withdrawals") } // Finalize block c.Finalize(chain, header, state, txs, uncles, nil) // Assign the final state root to header. header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number)) // 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 { return errors.New("sealing paused while waiting for transactions") } // 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 { return errors.New("signed recently, must wait for others") } } } // 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 } c.lock.RLock() signer := c.signer c.lock.RUnlock() return calcDifficulty(snap, 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", Service: &API{chain: chain, clique: c}, }} } // 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.(crypto.KeccakState).Read(hash[:]) 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) { enc := []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 header.BaseFee != nil { enc = append(enc, header.BaseFee) } if header.WithdrawalsHash != nil { panic("unexpected withdrawal hash value in clique") } if err := rlp.Encode(w, enc); err != nil { panic("can't encode: " + err.Error()) } }