685 lines
25 KiB
Go
685 lines
25 KiB
Go
// 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/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/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 = 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 = 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")
|
|
|
|
// errInvalidCheckpointSigners is returned if a checkpoint block contains an
|
|
// invalid list of signers (i.e. non divisible by 20 bytes, or not the correct
|
|
// ones).
|
|
errInvalidCheckpointSigners = 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")
|
|
|
|
// errWaitTransactions is returned if an empty block is attempted to be sealed
|
|
// on an instant chain (0 second period). It's important to refuse these as the
|
|
// block reward is zero, so an empty block just bloats the chain... fast.
|
|
errWaitTransactions = errors.New("waiting for transactions")
|
|
)
|
|
|
|
// 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, 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(sigHash(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
|
|
}
|
|
|
|
// 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.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 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.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 errInvalidCheckpointSigners
|
|
}
|
|
}
|
|
// 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.signatures, c.db, hash); err == nil {
|
|
log.Trace("Loaded voting snapshot from 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, c.signatures, 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
|
|
}
|
|
|
|
// 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 errUnauthorized
|
|
}
|
|
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 errUnauthorized
|
|
}
|
|
}
|
|
}
|
|
// Ensure that the difficulty corresponds 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 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 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
|
|
}
|
|
// 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 nil, errWaitTransactions
|
|
}
|
|
// 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 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")
|
|
<-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()) // 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))
|
|
}
|
|
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
|
|
}
|
|
|
|
// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
|
|
// that a new block should have based on the previous blocks in the chain and the
|
|
// current signer.
|
|
func (c *Clique) CalcDifficulty(chain consensus.ChainReader, 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)
|
|
}
|
|
|
|
// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
|
|
// that a new block should have based on the previous blocks in the chain and the
|
|
// current 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)
|
|
}
|
|
|
|
// 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,
|
|
}}
|
|
}
|