path: root/consensus/clique/clique.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"
	"io"
	"math/big"
	"math/rand"
	"sync"
	"time"

	"github.com/ava-labs/coreth/accounts"
	"github.com/ava-labs/coreth/consensus"
	"github.com/ava-labs/coreth/consensus/misc"
	"github.com/ava-labs/coreth/core/state"
	"github.com/ava-labs/coreth/core/types"
	"github.com/ava-labs/coreth/params"
	"github.com/ava-labs/coreth/rpc"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/ethereum/go-ethereum/trie"
	lru "github.com/hashicorp/golang-lru"
	"golang.org/x/crypto/sha3"
)

const (
	checkpointInterval = 1024 // Number of blocks after which to save the vote snapshot to the database
	inmemorySnapshots  = 128  // Number of recent vote snapshots to keep in memory
	inmemorySignatures = 4096 // Number of recent block signatures to keep in memory

	wiggleTime = 500 * time.Millisecond // Random delay (per signer) to allow concurrent signers
)

// Clique proof-of-authority protocol constants.
var (
	epochLength = uint64(30000) // Default number of blocks after which to checkpoint and reset the pending votes

	extraVanity = 32                     // Fixed number of extra-data prefix bytes reserved for signer vanity
	extraSeal   = crypto.SignatureLength // Fixed number of extra-data suffix bytes reserved for signer seal

	nonceAuthVote = hexutil.MustDecode("0xffffffffffffffff") // Magic nonce number to vote on adding a new signer
	nonceDropVote = hexutil.MustDecode("0x0000000000000000") // Magic nonce number to vote on removing a signer.

	uncleHash = types.CalcUncleHash(nil) // Always Keccak256(RLP([])) as uncles are meaningless outside of PoW.

	diffInTurn = big.NewInt(2) // Block difficulty for in-turn signatures
	diffNoTurn = big.NewInt(1) // Block difficulty for out-of-turn signatures
)

// Various error messages to mark blocks invalid. These should be private to
// prevent engine specific errors from being referenced in the remainder of the
// codebase, inherently breaking if the engine is swapped out. Please put common
// error types into the consensus package.
var (
	// errUnknownBlock is returned when the list of signers is requested for a block
	// that is not part of the local blockchain.
	errUnknownBlock = errors.New