go-ethereum/consensus/clique/snapshot.go
Péter Szilágyi be65b47645
all: update golang/x/ext and fix slice sorting fallout (#27909)
The Go authors updated golang/x/ext to change the function signature of the slices sort method. 
It's an entire shitshow now because x/ext is not tagged, so everyone's codebase just 
picked a new version that some other dep depends on, causing our code to fail building.

This PR updates the dep on our code too and does all the refactorings to follow upstream...
2023-08-12 00:04:12 +02:00

323 lines
11 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
import (
"bytes"
"encoding/json"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/lru"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
"golang.org/x/exp/slices"
)
// Vote represents a single vote that an authorized signer made to modify the
// list of authorizations.
type Vote struct {
Signer common.Address `json:"signer"` // Authorized signer that cast this vote
Block uint64 `json:"block"` // Block number the vote was cast in (expire old votes)
Address common.Address `json:"address"` // Account being voted on to change its authorization
Authorize bool `json:"authorize"` // Whether to authorize or deauthorize the voted account
}
// Tally is a simple vote tally to keep the current score of votes. Votes that
// go against the proposal aren't counted since it's equivalent to not voting.
type Tally struct {
Authorize bool `json:"authorize"` // Whether the vote is about authorizing or kicking someone
Votes int `json:"votes"` // Number of votes until now wanting to pass the proposal
}
type sigLRU = lru.Cache[common.Hash, common.Address]
// Snapshot is the state of the authorization voting at a given point in time.
type Snapshot struct {
config *params.CliqueConfig // Consensus engine parameters to fine tune behavior
sigcache *sigLRU // Cache of recent block signatures to speed up ecrecover
Number uint64 `json:"number"` // Block number where the snapshot was created
Hash common.Hash `json:"hash"` // Block hash where the snapshot was created
Signers map[common.Address]struct{} `json:"signers"` // Set of authorized signers at this moment
Recents map[uint64]common.Address `json:"recents"` // Set of recent signers for spam protections
Votes []*Vote `json:"votes"` // List of votes cast in chronological order
Tally map[common.Address]Tally `json:"tally"` // Current vote tally to avoid recalculating
}
// newSnapshot creates a new snapshot with the specified startup parameters. This
// method does not initialize the set of recent signers, so only ever use if for
// the genesis block.
func newSnapshot(config *params.CliqueConfig, sigcache *sigLRU, number uint64, hash common.Hash, signers []common.Address) *Snapshot {
snap := &Snapshot{
config: config,
sigcache: sigcache,
Number: number,
Hash: hash,
Signers: make(map[common.Address]struct{}),
Recents: make(map[uint64]common.Address),
Tally: make(map[common.Address]Tally),
}
for _, signer := range signers {
snap.Signers[signer] = struct{}{}
}
return snap
}
// loadSnapshot loads an existing snapshot from the database.
func loadSnapshot(config *params.CliqueConfig, sigcache *sigLRU, db ethdb.Database, hash common.Hash) (*Snapshot, error) {
blob, err := db.Get(append(rawdb.CliqueSnapshotPrefix, hash[:]...))
if err != nil {
return nil, err
}
snap := new(Snapshot)
if err := json.Unmarshal(blob, snap); err != nil {
return nil, err
}
snap.config = config
snap.sigcache = sigcache
return snap, nil
}
// store inserts the snapshot into the database.
func (s *Snapshot) store(db ethdb.Database) error {
blob, err := json.Marshal(s)
if err != nil {
return err
}
return db.Put(append(rawdb.CliqueSnapshotPrefix, s.Hash[:]...), blob)
}
// copy creates a deep copy of the snapshot, though not the individual votes.
func (s *Snapshot) copy() *Snapshot {
cpy := &Snapshot{
config: s.config,
sigcache: s.sigcache,
Number: s.Number,
Hash: s.Hash,
Signers: make(map[common.Address]struct{}),
Recents: make(map[uint64]common.Address),
Votes: make([]*Vote, len(s.Votes)),
Tally: make(map[common.Address]Tally),
}
for signer := range s.Signers {
cpy.Signers[signer] = struct{}{}
}
for block, signer := range s.Recents {
cpy.Recents[block] = signer
}
for address, tally := range s.Tally {
cpy.Tally[address] = tally
}
copy(cpy.Votes, s.Votes)
return cpy
}
// validVote returns whether it makes sense to cast the specified vote in the
// given snapshot context (e.g. don't try to add an already authorized signer).
func (s *Snapshot) validVote(address common.Address, authorize bool) bool {
_, signer := s.Signers[address]
return (signer && !authorize) || (!signer && authorize)
}
// cast adds a new vote into the tally.
func (s *Snapshot) cast(address common.Address, authorize bool) bool {
// Ensure the vote is meaningful
if !s.validVote(address, authorize) {
return false
}
// Cast the vote into an existing or new tally
if old, ok := s.Tally[address]; ok {
old.Votes++
s.Tally[address] = old
} else {
s.Tally[address] = Tally{Authorize: authorize, Votes: 1}
}
return true
}
// uncast removes a previously cast vote from the tally.
func (s *Snapshot) uncast(address common.Address, authorize bool) bool {
// If there's no tally, it's a dangling vote, just drop
tally, ok := s.Tally[address]
if !ok {
return false
}
// Ensure we only revert counted votes
if tally.Authorize != authorize {
return false
}
// Otherwise revert the vote
if tally.Votes > 1 {
tally.Votes--
s.Tally[address] = tally
} else {
delete(s.Tally, address)
}
return true
}
// apply creates a new authorization snapshot by applying the given headers to
// the original one.
func (s *Snapshot) apply(headers []*types.Header) (*Snapshot, error) {
// Allow passing in no headers for cleaner code
if len(headers) == 0 {
return s, nil
}
// Sanity check that the headers can be applied
for i := 0; i < len(headers)-1; i++ {
if headers[i+1].Number.Uint64() != headers[i].Number.Uint64()+1 {
return nil, errInvalidVotingChain
}
}
if headers[0].Number.Uint64() != s.Number+1 {
return nil, errInvalidVotingChain
}
// Iterate through the headers and create a new snapshot
snap := s.copy()
var (
start = time.Now()
logged = time.Now()
)
for i, header := range headers {
// Remove any votes on checkpoint blocks
number := header.Number.Uint64()
if number%s.config.Epoch == 0 {
snap.Votes = nil
snap.Tally = make(map[common.Address]Tally)
}
// Delete the oldest signer from the recent list to allow it signing again
if limit := uint64(len(snap.Signers)/2 + 1); number >= limit {
delete(snap.Recents, number-limit)
}
// Resolve the authorization key and check against signers
signer, err := ecrecover(header, s.sigcache)
if err != nil {
return nil, err
}
if _, ok := snap.Signers[signer]; !ok {
return nil, errUnauthorizedSigner
}
for _, recent := range snap.Recents {
if recent == signer {
return nil, errRecentlySigned
}
}
snap.Recents[number] = signer
// Header authorized, discard any previous votes from the signer
for i, vote := range snap.Votes {
if vote.Signer == signer && vote.Address == header.Coinbase {
// Uncast the vote from the cached tally
snap.uncast(vote.Address, vote.Authorize)
// Uncast the vote from the chronological list
snap.Votes = append(snap.Votes[:i], snap.Votes[i+1:]...)
break // only one vote allowed
}
}
// Tally up the new vote from the signer
var authorize bool
switch {
case bytes.Equal(header.Nonce[:], nonceAuthVote):
authorize = true
case bytes.Equal(header.Nonce[:], nonceDropVote):
authorize = false
default:
return nil, errInvalidVote
}
if snap.cast(header.Coinbase, authorize) {
snap.Votes = append(snap.Votes, &Vote{
Signer: signer,
Block: number,
Address: header.Coinbase,
Authorize: authorize,
})
}
// If the vote passed, update the list of signers
if tally := snap.Tally[header.Coinbase]; tally.Votes > len(snap.Signers)/2 {
if tally.Authorize {
snap.Signers[header.Coinbase] = struct{}{}
} else {
delete(snap.Signers, header.Coinbase)
// Signer list shrunk, delete any leftover recent caches
if limit := uint64(len(snap.Signers)/2 + 1); number >= limit {
delete(snap.Recents, number-limit)
}
// Discard any previous votes the deauthorized signer cast
for i := 0; i < len(snap.Votes); i++ {
if snap.Votes[i].Signer == header.Coinbase {
// Uncast the vote from the cached tally
snap.uncast(snap.Votes[i].Address, snap.Votes[i].Authorize)
// Uncast the vote from the chronological list
snap.Votes = append(snap.Votes[:i], snap.Votes[i+1:]...)
i--
}
}
}
// Discard any previous votes around the just changed account
for i := 0; i < len(snap.Votes); i++ {
if snap.Votes[i].Address == header.Coinbase {
snap.Votes = append(snap.Votes[:i], snap.Votes[i+1:]...)
i--
}
}
delete(snap.Tally, header.Coinbase)
}
// If we're taking too much time (ecrecover), notify the user once a while
if time.Since(logged) > 8*time.Second {
log.Info("Reconstructing voting history", "processed", i, "total", len(headers), "elapsed", common.PrettyDuration(time.Since(start)))
logged = time.Now()
}
}
if time.Since(start) > 8*time.Second {
log.Info("Reconstructed voting history", "processed", len(headers), "elapsed", common.PrettyDuration(time.Since(start)))
}
snap.Number += uint64(len(headers))
snap.Hash = headers[len(headers)-1].Hash()
return snap, nil
}
// signers retrieves the list of authorized signers in ascending order.
func (s *Snapshot) signers() []common.Address {
sigs := make([]common.Address, 0, len(s.Signers))
for sig := range s.Signers {
sigs = append(sigs, sig)
}
slices.SortFunc(sigs, common.Address.Cmp)
return sigs
}
// inturn returns if a signer at a given block height is in-turn or not.
func (s *Snapshot) inturn(number uint64, signer common.Address) bool {
signers, offset := s.signers(), 0
for offset < len(signers) && signers[offset] != signer {
offset++
}
return (number % uint64(len(signers))) == uint64(offset)
}