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authorDeterminant <[email protected]>2020-06-28 14:47:41 -0400
committerDeterminant <[email protected]>2020-06-28 14:47:41 -0400
commitd235e2c6a5788ec4a6cff15a16f56b38a3876a0d (patch)
tree5f2727f7a50ee5840f889c82776d3a30a88dd59b /consensus/clique/snapshot.go
parent13ebd8bd9468e9d769d598b0ca2afb72ba78cb97 (diff)
...
Diffstat (limited to 'consensus/clique/snapshot.go')
-rw-r--r--consensus/clique/snapshot.go326
1 files changed, 326 insertions, 0 deletions
diff --git a/consensus/clique/snapshot.go b/consensus/clique/snapshot.go
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+// 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"
+ "sort"
+ "time"
+
+ "github.com/ava-labs/coreth/core/types"
+ "github.com/ava-labs/coreth/params"
+ "github.com/ava-labs/go-ethereum/common"
+ "github.com/ava-labs/go-ethereum/ethdb"
+ "github.com/ava-labs/go-ethereum/log"
+ lru "github.com/hashicorp/golang-lru"
+)
+
+// 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
+}
+
+// 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 *lru.ARCCache // 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
+}
+
+// signersAscending implements the sort interface to allow sorting a list of addresses
+type signersAscending []common.Address
+
+func (s signersAscending) Len() int { return len(s) }
+func (s signersAscending) Less(i, j int) bool { return bytes.Compare(s[i][:], s[j][:]) < 0 }
+func (s signersAscending) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+// 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 *lru.ARCCache, 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 *lru.ARCCache, db ethdb.Database, hash common.Hash) (*Snapshot, error) {
+ blob, err := db.Get(append([]byte("clique-"), 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([]byte("clique-"), 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)
+ }
+ sort.Sort(signersAscending(sigs))
+ 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)
+}