consensus/clique: Proof of Authority (#3753)
This PR is a prototype implementation of plugable consensus engines and the Clique PoA protocol ethereum/EIPs#225
This commit is contained in:
Péter Szilágyi
committed by
Felix Lange
Felix Lange
parent
bfe5eb7f8c
commit
feeccdf4ec
638
consensus/clique/clique.go
Normal file
638
consensus/clique/clique.go
Normal file
@ -0,0 +1,638 @@
|
||||
// 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"
|
||||
"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/core/state"
|
||||
"github.com/ethereum/go-ethereum/core/types"
|
||||
"github.com/ethereum/go-ethereum/crypto"
|
||||
"github.com/ethereum/go-ethereum/crypto/sha3"
|
||||
"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"
|
||||
lru "github.com/hashicorp/golang-lru"
|
||||
)
|
||||
|
||||
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 = 1024 // Number of recent blocks 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
|
||||
blockPeriod = uint64(15) // Default minimum difference between two consecutive block's timestamps
|
||||
|
||||
extraVanity = 32 // Fixed number of extra-data prefix bytes reserved for signer vanity
|
||||
extraSeal = 65 // 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 suffix signature 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")
|
||||
|
||||
// drrInvalidCheckpointSigners is returned if a checkpoint block contains an
|
||||
// invalid list of signers (i.e. non divisible by 20 bytes, or not the correct
|
||||
// ones).
|
||||
drrInvalidCheckpointSigners = errors.New("invalid 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 is not either
|
||||
// of 1 or 2, or if the value does not match the turn of the signer.
|
||||
errInvalidDifficulty = errors.New("invalid 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")
|
||||
|
||||
// errUnauthorized is returned if a header is signed by a non authorized entity.
|
||||
errUnauthorized = errors.New("unauthorized")
|
||||
)
|
||||
|
||||
// SignerFn is a signer callback function to request a hash to be signed by a
|
||||
// backing account.
|
||||
type SignerFn func(accounts.Account, []byte) ([]byte, error)
|
||||
|
||||
// sigHash returns the hash which is used as input for the proof-of-authority
|
||||
// signing. It is the hash 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 sigHash(header *types.Header) (hash common.Hash) {
|
||||
hasher := sha3.NewKeccak256()
|
||||
|
||||
rlp.Encode(hasher, []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)-65], // Yes, this will panic if extra is too short
|
||||
header.MixDigest,
|
||||
header.Nonce,
|
||||
})
|
||||
hasher.Sum(hash[:0])
|
||||
return hash
|
||||
}
|
||||
|
||||
// ecrecover extracts the Ethereum account address from a signed header.
|
||||
func ecrecover(header *types.Header) (common.Address, error) {
|
||||
// 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(sigHash(header).Bytes(), signature)
|
||||
if err != nil {
|
||||
return common.Address{}, err
|
||||
}
|
||||
var signer common.Address
|
||||
copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
|
||||
|
||||
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
|
||||
}
|
||||
|
||||
// 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
|
||||
}
|
||||
if conf.Period == 0 {
|
||||
conf.Period = blockPeriod
|
||||
}
|
||||
// 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),
|
||||
}
|
||||
}
|
||||
|
||||
// VerifyHeader checks whether a header conforms to the consensus rules.
|
||||
func (c *Clique) VerifyHeader(chain consensus.ChainReader, 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.ChainReader, 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.ChainReader, 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.Cmp(big.NewInt(time.Now().Unix())) > 0 {
|
||||
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 drrInvalidCheckpointSigners
|
||||
}
|
||||
// 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
|
||||
}
|
||||
}
|
||||
// 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.ChainReader, 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 it's 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.Uint64()+c.config.Period > header.Time.Uint64() {
|
||||
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 drrInvalidCheckpointSigners
|
||||
}
|
||||
}
|
||||
// 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.ChainReader, 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.db, hash); err == nil {
|
||||
log.Trace("Loaded voting snapshot form disk", "number", number, "hash", hash)
|
||||
snap = s
|
||||
break
|
||||
}
|
||||
}
|
||||
// If we're at block zero, make a snapshot
|
||||
if number == 0 {
|
||||
genesis := chain.GetHeaderByNumber(0)
|
||||
if err := c.VerifyHeader(chain, genesis, false); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
signers := make([]common.Address, (len(genesis.Extra)-extraVanity-extraSeal)/common.AddressLength)
|
||||
for i := 0; i < len(signers); i++ {
|
||||
copy(signers[i][:], genesis.Extra[extraVanity+i*common.AddressLength:])
|
||||
}
|
||||
snap = newSnapshot(c.config, 0, genesis.Hash(), signers)
|
||||
if err := snap.store(c.db); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
log.Trace("Stored genesis voting snapshot to disk")
|
||||
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 implements consensus.Engine, checking whether the signature contained
|
||||
// in the header satisfies the consensus protocol requirements.
|
||||
func (c *Clique) VerifySeal(chain consensus.ChainReader, header *types.Header) error {
|
||||
return c.verifySeal(chain, header, 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.ChainReader, 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
|
||||
}
|
||||
c.recents.Add(snap.Hash, snap)
|
||||
|
||||
// Resolve the authorization key and check against signers
|
||||
signer, err := ecrecover(header)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
if _, ok := snap.Signers[signer]; !ok {
|
||||
return errUnauthorized
|
||||
}
|
||||
for seen, recent := range snap.Recents {
|
||||
if recent == signer {
|
||||
// Signer is among recents, only fail if the current block doens't shift it out
|
||||
if limit := uint64(len(snap.Signers)/2 + 1); seen > number-limit {
|
||||
return errUnauthorized
|
||||
}
|
||||
}
|
||||
}
|
||||
// Ensure that the difficulty corresponts to the turn-ness of the signer
|
||||
inturn := snap.inturn(header.Number.Uint64(), signer)
|
||||
if inturn && header.Difficulty.Cmp(diffInTurn) != 0 {
|
||||
return errInvalidDifficulty
|
||||
}
|
||||
if !inturn && header.Difficulty.Cmp(diffNoTurn) != 0 {
|
||||
return errInvalidDifficulty
|
||||
}
|
||||
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.ChainReader, header *types.Header) error {
|
||||
// If the block isn't a checkpoint, cast a random vote (good enough fror now)
|
||||
header.Coinbase = common.Address{}
|
||||
header.Nonce = types.BlockNonce{}
|
||||
|
||||
number := header.Number.Uint64()
|
||||
if number%c.config.Epoch != 0 {
|
||||
c.lock.RLock()
|
||||
if len(c.proposals) > 0 {
|
||||
addresses := make([]common.Address, 0, len(c.proposals))
|
||||
for address := range c.proposals {
|
||||
addresses = append(addresses, address)
|
||||
}
|
||||
header.Coinbase = addresses[rand.Intn(len(addresses))]
|
||||
if c.proposals[header.Coinbase] {
|
||||
copy(header.Nonce[:], nonceAuthVote)
|
||||
} else {
|
||||
copy(header.Nonce[:], nonceDropVote)
|
||||
}
|
||||
}
|
||||
c.lock.RUnlock()
|
||||
}
|
||||
// Assemble the voting snapshot and set the correct difficulty
|
||||
snap, err := c.snapshot(chain, number-1, header.ParentHash, nil)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
header.Difficulty = diffNoTurn
|
||||
if snap.inturn(header.Number.Uint64(), c.signer) {
|
||||
header.Difficulty = diffInTurn
|
||||
}
|
||||
// Ensure the extra data has all it's 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 = new(big.Int).Add(parent.Time, new(big.Int).SetUint64(c.config.Period))
|
||||
if header.Time.Int64() < time.Now().Unix() {
|
||||
header.Time = big.NewInt(time.Now().Unix())
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// Finalize implements consensus.Engine, ensuring no uncles are set, nor block
|
||||
// rewards given, and returns the final block.
|
||||
func (c *Clique) Finalize(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error) {
|
||||
// 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)
|
||||
|
||||
// Assemble and return the final block for sealing
|
||||
return types.NewBlock(header, txs, nil, receipts), 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.ChainReader, block *types.Block, stop <-chan struct{}) (*types.Block, error) {
|
||||
header := block.Header()
|
||||
|
||||
// Sealing the genesis block is not supported
|
||||
number := header.Number.Uint64()
|
||||
if number == 0 {
|
||||
return nil, errUnknownBlock
|
||||
}
|
||||
// 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 nil, err
|
||||
}
|
||||
if _, authorized := snap.Signers[signer]; !authorized {
|
||||
return nil, errUnauthorized
|
||||
}
|
||||
// If we're amongs 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 doens't shift it out
|
||||
if limit := uint64(len(snap.Signers)/2 + 1); seen > number-limit {
|
||||
log.Info("Signed recently, must wait for others")
|
||||
<-stop
|
||||
return nil, nil
|
||||
}
|
||||
}
|
||||
}
|
||||
// Sweet, the protocol permits us to sign the block, wait for our time
|
||||
delay := time.Unix(header.Time.Int64(), 0).Sub(time.Now())
|
||||
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))
|
||||
}
|
||||
log.Trace("Waiting for slot to sign and propagate", "delay", common.PrettyDuration(delay))
|
||||
|
||||
select {
|
||||
case <-stop:
|
||||
return nil, nil
|
||||
case <-time.After(delay):
|
||||
}
|
||||
// Sign all the things!
|
||||
sighash, err := signFn(accounts.Account{Address: signer}, sigHash(header).Bytes())
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
copy(header.Extra[len(header.Extra)-extraSeal:], sighash)
|
||||
|
||||
return block.WithSeal(header), nil
|
||||
}
|
||||
|
||||
// APIs implements consensus.Engine, returning the user facing RPC API to allow
|
||||
// controlling the signer voting.
|
||||
func (c *Clique) APIs(chain consensus.ChainReader) []rpc.API {
|
||||
return []rpc.API{{
|
||||
Namespace: "clique",
|
||||
Version: "1.0",
|
||||
Service: &API{chain: chain, clique: c},
|
||||
Public: false,
|
||||
}}
|
||||
}
|
||||
Reference in New Issue
Block a user