go-ethereum/consensus/bor/snapshot.go
2019-09-04 19:20:28 +05:30

380 lines
13 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 bor
import (
"bytes"
"encoding/json"
"fmt"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/params"
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.BorConfig // Consensus engine parameters to fine tune behavior
ethAPI *ethapi.PublicBlockChainAPI
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
ValidatorSet *ValidatorSet `json:"validatorSet"` // Validator set 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.BorConfig, sigcache *lru.ARCCache, number uint64, hash common.Hash, validators []*Validator, ethAPI *ethapi.PublicBlockChainAPI) *Snapshot {
snap := &Snapshot{
config: config,
ethAPI: ethAPI,
sigcache: sigcache,
Number: number,
Hash: hash,
ValidatorSet: NewValidatorSet(validators),
Recents: make(map[uint64]common.Address),
// Tally: make(map[common.Address]Tally),
}
fmt.Println("New validator set", "number", number, "proposer", snap.ValidatorSet.Proposer.Address.Hex())
return snap
}
// loadSnapshot loads an existing snapshot from the database.
func loadSnapshot(config *params.BorConfig, sigcache *lru.ARCCache, db ethdb.Database, hash common.Hash, ethAPI *ethapi.PublicBlockChainAPI) (*Snapshot, error) {
blob, err := db.Get(append([]byte("bor-"), 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
snap.ethAPI = ethAPI
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("bor-"), 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,
ethAPI: s.ethAPI,
sigcache: s.sigcache,
Number: s.Number,
Hash: s.Hash,
ValidatorSet: s.ValidatorSet.Copy(),
Recents: make(map[uint64]common.Address),
// Votes: make([]*Vote, len(s.Votes)),
// Tally: make(map[common.Address]Tally),
}
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
// }
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, errOutOfRangeChain
}
}
if headers[0].Number.Uint64() != s.Number+1 {
return nil, errOutOfRangeChain
}
// Iterate through the headers and create a new snapshot
snap := s.copy()
for _, header := range headers {
// Remove any votes on checkpoint blocks
number := header.Number.Uint64()
if (number+1)%s.config.Sprint == 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 number >= s.config.Sprint && number-s.config.Sprint >= 0 {
delete(snap.Recents, number-s.config.Sprint)
}
// Resolve the authorization key and check against signers
signer, err := ecrecover(header, s.sigcache)
if err != nil {
return nil, err
}
if !snap.ValidatorSet.HasAddress(signer.Bytes()) {
return nil, errUnauthorizedSigner
}
//
// Check validator
//
validators := snap.ValidatorSet.Validators
// proposer will be the last signer if block is not epoch block
proposer := snap.ValidatorSet.GetProposer().Address
// if number%s.config.Sprint != 0 {
// proposer = snap.Recents[number-1]
// }
proposerIndex, _ := snap.ValidatorSet.GetByAddress(proposer)
signerIndex, _ := snap.ValidatorSet.GetByAddress(signer)
limit := len(validators) - (len(validators)/2 + 1)
// temp index
tempIndex := signerIndex
if proposerIndex != tempIndex && limit > 0 {
if tempIndex < proposerIndex {
tempIndex = tempIndex + len(validators)
}
if tempIndex-proposerIndex > limit {
return nil, errRecentlySigned
}
}
// add recents
snap.Recents[number] = signer
// TODO remove
fmt.Println("Recent signer", "number", number, "signer", signer.Hex())
// change proposer on epoch
if number > 0 && (number+1)%s.config.Sprint == 0 {
newVals, _ := GetValidators(number, s.config.Sprint, s.config.ValidatorContract, snap.ethAPI)
v := getUpdatedValidatorSet(snap.ValidatorSet.Copy(), newVals)
v.IncrementProposerPriority(1)
snap.ValidatorSet = v
fmt.Println("New validator set", "number", number, "proposer", v.Proposer.Address.Hex())
}
// // 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)
// }
}
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.ValidatorSet.Validators))
for _, sig := range s.ValidatorSet.Validators {
sigs = append(sigs, sig.Address)
}
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, epoch uint64) uint64 {
// if signer is empty
if bytes.Compare(signer.Bytes(), common.Address{}.Bytes()) == 0 {
return 1
}
validators := s.ValidatorSet.Validators
proposer := s.ValidatorSet.GetProposer().Address
totalValidators := len(validators)
// proposer will be the last signer if block is not epoch block
// proposer := snap.ValidatorSet.GetProposer().Address
// if number%epoch != 0 {
// proposer = snap.Recents[number-1]
// }
proposerIndex, _ := s.ValidatorSet.GetByAddress(proposer)
signerIndex, _ := s.ValidatorSet.GetByAddress(signer)
// temp index
tempIndex := signerIndex
if tempIndex < proposerIndex {
tempIndex = tempIndex + totalValidators
}
return uint64(totalValidators - (tempIndex - proposerIndex))
// signers, offset := s.signers(), 0
// for offset < len(signers) && signers[offset] != signer {
// offset++
// }
// return ((number / producerPeriod) % uint64(len(signers))) == uint64(offset)
// // if block is epoch start block, proposer will be inturn signer
// if s.Number%epoch == 0 {
// if bytes.Compare(proposer.Address.Bytes(), signer.Bytes()) == 0 {
// return true
// }
// // if block is not epoch block, last block signer will be inturn
// } else if bytes.Compare(lastSigner.Bytes(), signer.Bytes()) == 0 {
// return false
// }
// return false
}