686 lines
25 KiB
Go
686 lines
25 KiB
Go
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package clique implements the proof-of-authority consensus engine.
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package clique
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import (
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"bytes"
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"errors"
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"math/big"
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"math/rand"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/accounts"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/common/hexutil"
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"github.com/ethereum/go-ethereum/consensus"
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"github.com/ethereum/go-ethereum/consensus/misc"
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"github.com/ethereum/go-ethereum/core/state"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/crypto/sha3"
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"github.com/ethereum/go-ethereum/ethdb"
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"github.com/ethereum/go-ethereum/log"
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"github.com/ethereum/go-ethereum/params"
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"github.com/ethereum/go-ethereum/rlp"
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"github.com/ethereum/go-ethereum/rpc"
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lru "github.com/hashicorp/golang-lru"
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)
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const (
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checkpointInterval = 1024 // Number of blocks after which to save the vote snapshot to the database
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inmemorySnapshots = 128 // Number of recent vote snapshots to keep in memory
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inmemorySignatures = 4096 // Number of recent block signatures to keep in memory
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wiggleTime = 500 * time.Millisecond // Random delay (per signer) to allow concurrent signers
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)
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// Clique proof-of-authority protocol constants.
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var (
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epochLength = uint64(30000) // Default number of blocks after which to checkpoint and reset the pending votes
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blockPeriod = uint64(15) // Default minimum difference between two consecutive block's timestamps
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extraVanity = 32 // Fixed number of extra-data prefix bytes reserved for signer vanity
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extraSeal = 65 // Fixed number of extra-data suffix bytes reserved for signer seal
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nonceAuthVote = hexutil.MustDecode("0xffffffffffffffff") // Magic nonce number to vote on adding a new signer
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nonceDropVote = hexutil.MustDecode("0x0000000000000000") // Magic nonce number to vote on removing a signer.
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uncleHash = types.CalcUncleHash(nil) // Always Keccak256(RLP([])) as uncles are meaningless outside of PoW.
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diffInTurn = big.NewInt(2) // Block difficulty for in-turn signatures
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diffNoTurn = big.NewInt(1) // Block difficulty for out-of-turn signatures
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)
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// Various error messages to mark blocks invalid. These should be private to
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// prevent engine specific errors from being referenced in the remainder of the
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// codebase, inherently breaking if the engine is swapped out. Please put common
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// error types into the consensus package.
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var (
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// errUnknownBlock is returned when the list of signers is requested for a block
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// that is not part of the local blockchain.
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errUnknownBlock = errors.New("unknown block")
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// errInvalidCheckpointBeneficiary is returned if a checkpoint/epoch transition
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// block has a beneficiary set to non-zeroes.
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errInvalidCheckpointBeneficiary = errors.New("beneficiary in checkpoint block non-zero")
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// errInvalidVote is returned if a nonce value is something else that the two
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// allowed constants of 0x00..0 or 0xff..f.
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errInvalidVote = errors.New("vote nonce not 0x00..0 or 0xff..f")
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// errInvalidCheckpointVote is returned if a checkpoint/epoch transition block
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// has a vote nonce set to non-zeroes.
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errInvalidCheckpointVote = errors.New("vote nonce in checkpoint block non-zero")
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// errMissingVanity is returned if a block's extra-data section is shorter than
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// 32 bytes, which is required to store the signer vanity.
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errMissingVanity = errors.New("extra-data 32 byte vanity prefix missing")
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// errMissingSignature is returned if a block's extra-data section doesn't seem
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// to contain a 65 byte secp256k1 signature.
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errMissingSignature = errors.New("extra-data 65 byte suffix signature missing")
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// errExtraSigners is returned if non-checkpoint block contain signer data in
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// their extra-data fields.
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errExtraSigners = errors.New("non-checkpoint block contains extra signer list")
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// errInvalidCheckpointSigners is returned if a checkpoint block contains an
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// invalid list of signers (i.e. non divisible by 20 bytes, or not the correct
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// ones).
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errInvalidCheckpointSigners = errors.New("invalid signer list on checkpoint block")
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// errInvalidMixDigest is returned if a block's mix digest is non-zero.
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errInvalidMixDigest = errors.New("non-zero mix digest")
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// errInvalidUncleHash is returned if a block contains an non-empty uncle list.
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errInvalidUncleHash = errors.New("non empty uncle hash")
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// errInvalidDifficulty is returned if the difficulty of a block is not either
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// of 1 or 2, or if the value does not match the turn of the signer.
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errInvalidDifficulty = errors.New("invalid difficulty")
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// ErrInvalidTimestamp is returned if the timestamp of a block is lower than
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// the previous block's timestamp + the minimum block period.
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ErrInvalidTimestamp = errors.New("invalid timestamp")
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// errInvalidVotingChain is returned if an authorization list is attempted to
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// be modified via out-of-range or non-contiguous headers.
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errInvalidVotingChain = errors.New("invalid voting chain")
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// errUnauthorized is returned if a header is signed by a non-authorized entity.
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errUnauthorized = errors.New("unauthorized")
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// errWaitTransactions is returned if an empty block is attempted to be sealed
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// on an instant chain (0 second period). It's important to refuse these as the
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// block reward is zero, so an empty block just bloats the chain... fast.
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errWaitTransactions = errors.New("waiting for transactions")
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)
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// SignerFn is a signer callback function to request a hash to be signed by a
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// backing account.
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type SignerFn func(accounts.Account, []byte) ([]byte, error)
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// sigHash returns the hash which is used as input for the proof-of-authority
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// signing. It is the hash of the entire header apart from the 65 byte signature
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// contained at the end of the extra data.
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//
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// Note, the method requires the extra data to be at least 65 bytes, otherwise it
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// panics. This is done to avoid accidentally using both forms (signature present
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// or not), which could be abused to produce different hashes for the same header.
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func sigHash(header *types.Header) (hash common.Hash) {
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hasher := sha3.NewKeccak256()
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rlp.Encode(hasher, []interface{}{
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header.ParentHash,
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header.UncleHash,
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header.Coinbase,
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header.Root,
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header.TxHash,
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header.ReceiptHash,
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header.Bloom,
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header.Difficulty,
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header.Number,
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header.GasLimit,
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header.GasUsed,
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header.Time,
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header.Extra[:len(header.Extra)-65], // Yes, this will panic if extra is too short
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header.MixDigest,
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header.Nonce,
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})
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hasher.Sum(hash[:0])
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return hash
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}
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// ecrecover extracts the Ethereum account address from a signed header.
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func ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
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// If the signature's already cached, return that
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hash := header.Hash()
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if address, known := sigcache.Get(hash); known {
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return address.(common.Address), nil
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}
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// Retrieve the signature from the header extra-data
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if len(header.Extra) < extraSeal {
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return common.Address{}, errMissingSignature
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}
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signature := header.Extra[len(header.Extra)-extraSeal:]
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// Recover the public key and the Ethereum address
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pubkey, err := crypto.Ecrecover(sigHash(header).Bytes(), signature)
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if err != nil {
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return common.Address{}, err
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}
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var signer common.Address
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copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
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sigcache.Add(hash, signer)
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return signer, nil
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}
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// Clique is the proof-of-authority consensus engine proposed to support the
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// Ethereum testnet following the Ropsten attacks.
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type Clique struct {
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config *params.CliqueConfig // Consensus engine configuration parameters
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db ethdb.Database // Database to store and retrieve snapshot checkpoints
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recents *lru.ARCCache // Snapshots for recent block to speed up reorgs
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signatures *lru.ARCCache // Signatures of recent blocks to speed up mining
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proposals map[common.Address]bool // Current list of proposals we are pushing
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signer common.Address // Ethereum address of the signing key
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signFn SignerFn // Signer function to authorize hashes with
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lock sync.RWMutex // Protects the signer fields
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}
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// New creates a Clique proof-of-authority consensus engine with the initial
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// signers set to the ones provided by the user.
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func New(config *params.CliqueConfig, db ethdb.Database) *Clique {
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// Set any missing consensus parameters to their defaults
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conf := *config
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if conf.Epoch == 0 {
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conf.Epoch = epochLength
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}
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// Allocate the snapshot caches and create the engine
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recents, _ := lru.NewARC(inmemorySnapshots)
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signatures, _ := lru.NewARC(inmemorySignatures)
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return &Clique{
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config: &conf,
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db: db,
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recents: recents,
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signatures: signatures,
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proposals: make(map[common.Address]bool),
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}
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}
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// Author implements consensus.Engine, returning the Ethereum address recovered
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// from the signature in the header's extra-data section.
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func (c *Clique) Author(header *types.Header) (common.Address, error) {
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return ecrecover(header, c.signatures)
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}
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// VerifyHeader checks whether a header conforms to the consensus rules.
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func (c *Clique) VerifyHeader(chain consensus.ChainReader, header *types.Header, seal bool) error {
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return c.verifyHeader(chain, header, nil)
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}
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// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers. The
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// method returns a quit channel to abort the operations and a results channel to
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// retrieve the async verifications (the order is that of the input slice).
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func (c *Clique) VerifyHeaders(chain consensus.ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error) {
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abort := make(chan struct{})
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results := make(chan error, len(headers))
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go func() {
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for i, header := range headers {
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err := c.verifyHeader(chain, header, headers[:i])
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select {
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case <-abort:
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return
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case results <- err:
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}
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}
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}()
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return abort, results
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}
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// verifyHeader checks whether a header conforms to the consensus rules.The
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// caller may optionally pass in a batch of parents (ascending order) to avoid
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// looking those up from the database. This is useful for concurrently verifying
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// a batch of new headers.
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func (c *Clique) verifyHeader(chain consensus.ChainReader, header *types.Header, parents []*types.Header) error {
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if header.Number == nil {
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return errUnknownBlock
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}
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number := header.Number.Uint64()
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// Don't waste time checking blocks from the future
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if header.Time.Cmp(big.NewInt(time.Now().Unix())) > 0 {
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return consensus.ErrFutureBlock
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}
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// Checkpoint blocks need to enforce zero beneficiary
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checkpoint := (number % c.config.Epoch) == 0
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if checkpoint && header.Coinbase != (common.Address{}) {
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return errInvalidCheckpointBeneficiary
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}
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// Nonces must be 0x00..0 or 0xff..f, zeroes enforced on checkpoints
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if !bytes.Equal(header.Nonce[:], nonceAuthVote) && !bytes.Equal(header.Nonce[:], nonceDropVote) {
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return errInvalidVote
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}
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if checkpoint && !bytes.Equal(header.Nonce[:], nonceDropVote) {
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return errInvalidCheckpointVote
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}
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// Check that the extra-data contains both the vanity and signature
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if len(header.Extra) < extraVanity {
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return errMissingVanity
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}
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if len(header.Extra) < extraVanity+extraSeal {
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return errMissingSignature
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}
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// Ensure that the extra-data contains a signer list on checkpoint, but none otherwise
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signersBytes := len(header.Extra) - extraVanity - extraSeal
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if !checkpoint && signersBytes != 0 {
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return errExtraSigners
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}
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if checkpoint && signersBytes%common.AddressLength != 0 {
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return errInvalidCheckpointSigners
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}
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// Ensure that the mix digest is zero as we don't have fork protection currently
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if header.MixDigest != (common.Hash{}) {
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return errInvalidMixDigest
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}
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// Ensure that the block doesn't contain any uncles which are meaningless in PoA
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if header.UncleHash != uncleHash {
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return errInvalidUncleHash
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}
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// Ensure that the block's difficulty is meaningful (may not be correct at this point)
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if number > 0 {
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if header.Difficulty == nil || (header.Difficulty.Cmp(diffInTurn) != 0 && header.Difficulty.Cmp(diffNoTurn) != 0) {
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return errInvalidDifficulty
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}
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}
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// If all checks passed, validate any special fields for hard forks
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if err := misc.VerifyForkHashes(chain.Config(), header, false); err != nil {
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return err
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}
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// All basic checks passed, verify cascading fields
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return c.verifyCascadingFields(chain, header, parents)
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}
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// verifyCascadingFields verifies all the header fields that are not standalone,
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// rather depend on a batch of previous headers. The caller may optionally pass
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// in a batch of parents (ascending order) to avoid looking those up from the
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// database. This is useful for concurrently verifying a batch of new headers.
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func (c *Clique) verifyCascadingFields(chain consensus.ChainReader, header *types.Header, parents []*types.Header) error {
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// The genesis block is the always valid dead-end
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number := header.Number.Uint64()
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if number == 0 {
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return nil
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}
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// Ensure that the block's timestamp isn't too close to it's parent
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var parent *types.Header
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if len(parents) > 0 {
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parent = parents[len(parents)-1]
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} else {
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parent = chain.GetHeader(header.ParentHash, number-1)
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}
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if parent == nil || parent.Number.Uint64() != number-1 || parent.Hash() != header.ParentHash {
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return consensus.ErrUnknownAncestor
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}
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if parent.Time.Uint64()+c.config.Period > header.Time.Uint64() {
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return ErrInvalidTimestamp
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}
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// Retrieve the snapshot needed to verify this header and cache it
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snap, err := c.snapshot(chain, number-1, header.ParentHash, parents)
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if err != nil {
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return err
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}
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// If the block is a checkpoint block, verify the signer list
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if number%c.config.Epoch == 0 {
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signers := make([]byte, len(snap.Signers)*common.AddressLength)
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for i, signer := range snap.signers() {
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copy(signers[i*common.AddressLength:], signer[:])
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}
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extraSuffix := len(header.Extra) - extraSeal
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if !bytes.Equal(header.Extra[extraVanity:extraSuffix], signers) {
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return errInvalidCheckpointSigners
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}
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}
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// All basic checks passed, verify the seal and return
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return c.verifySeal(chain, header, parents)
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}
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// snapshot retrieves the authorization snapshot at a given point in time.
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func (c *Clique) snapshot(chain consensus.ChainReader, number uint64, hash common.Hash, parents []*types.Header) (*Snapshot, error) {
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// Search for a snapshot in memory or on disk for checkpoints
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var (
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headers []*types.Header
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snap *Snapshot
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)
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for snap == nil {
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// If an in-memory snapshot was found, use that
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if s, ok := c.recents.Get(hash); ok {
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snap = s.(*Snapshot)
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break
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}
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// If an on-disk checkpoint snapshot can be found, use that
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if number%checkpointInterval == 0 {
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if s, err := loadSnapshot(c.config, c.signatures, c.db, hash); err == nil {
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log.Trace("Loaded voting snapshot form disk", "number", number, "hash", hash)
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snap = s
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break
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}
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}
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// If we're at block zero, make a snapshot
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if number == 0 {
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genesis := chain.GetHeaderByNumber(0)
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if err := c.VerifyHeader(chain, genesis, false); err != nil {
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return nil, err
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}
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signers := make([]common.Address, (len(genesis.Extra)-extraVanity-extraSeal)/common.AddressLength)
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for i := 0; i < len(signers); i++ {
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copy(signers[i][:], genesis.Extra[extraVanity+i*common.AddressLength:])
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}
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snap = newSnapshot(c.config, c.signatures, 0, genesis.Hash(), signers)
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if err := snap.store(c.db); err != nil {
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return nil, err
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}
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log.Trace("Stored genesis voting snapshot to disk")
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break
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}
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// No snapshot for this header, gather the header and move backward
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var header *types.Header
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if len(parents) > 0 {
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// If we have explicit parents, pick from there (enforced)
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header = parents[len(parents)-1]
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if header.Hash() != hash || header.Number.Uint64() != number {
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return nil, consensus.ErrUnknownAncestor
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}
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parents = parents[:len(parents)-1]
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} else {
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// No explicit parents (or no more left), reach out to the database
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header = chain.GetHeader(hash, number)
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if header == nil {
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return nil, consensus.ErrUnknownAncestor
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}
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}
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headers = append(headers, header)
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number, hash = number-1, header.ParentHash
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}
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// Previous snapshot found, apply any pending headers on top of it
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for i := 0; i < len(headers)/2; i++ {
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headers[i], headers[len(headers)-1-i] = headers[len(headers)-1-i], headers[i]
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}
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snap, err := snap.apply(headers)
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if err != nil {
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return nil, err
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}
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c.recents.Add(snap.Hash, snap)
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// If we've generated a new checkpoint snapshot, save to disk
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if snap.Number%checkpointInterval == 0 && len(headers) > 0 {
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if err = snap.store(c.db); err != nil {
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return nil, err
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}
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log.Trace("Stored voting snapshot to disk", "number", snap.Number, "hash", snap.Hash)
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}
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return snap, err
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}
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// VerifyUncles implements consensus.Engine, always returning an error for any
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// uncles as this consensus mechanism doesn't permit uncles.
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func (c *Clique) VerifyUncles(chain consensus.ChainReader, block *types.Block) error {
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if len(block.Uncles()) > 0 {
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return errors.New("uncles not allowed")
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}
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return nil
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}
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// VerifySeal implements consensus.Engine, checking whether the signature contained
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// in the header satisfies the consensus protocol requirements.
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func (c *Clique) VerifySeal(chain consensus.ChainReader, header *types.Header) error {
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return c.verifySeal(chain, header, nil)
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}
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|
// 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,
|
|
}}
|
|
}
|