go-ethereum/consensus/XDPoS/engines/engine_v1/snapshot.go
2024-12-21 14:39:26 +08:00

287 lines
9.3 KiB
Go

package engine_v1
import (
"bytes"
"encoding/json"
"github.com/XinFinOrg/XDPoSChain/common"
"github.com/XinFinOrg/XDPoSChain/consensus/XDPoS/utils"
"github.com/XinFinOrg/XDPoSChain/consensus/clique"
"github.com/XinFinOrg/XDPoSChain/core/types"
"github.com/XinFinOrg/XDPoSChain/ethdb"
"github.com/XinFinOrg/XDPoSChain/params"
)
// 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 SnapshotV1 struct {
config *params.XDPoSConfig // Consensus engine parameters to fine tune behavior
sigcache *utils.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 []*clique.Vote `json:"votes"` // List of votes cast in chronological order
Tally map[common.Address]clique.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.XDPoSConfig, sigcache *utils.SigLRU, number uint64, hash common.Hash, signers []common.Address) *SnapshotV1 {
snap := &SnapshotV1{
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]clique.Tally),
}
for _, signer := range signers {
snap.Signers[signer] = struct{}{}
}
return snap
}
// loadSnapshot loads an existing snapshot from the database.
func loadSnapshot(config *params.XDPoSConfig, sigcache *utils.SigLRU, db ethdb.Database, hash common.Hash) (*SnapshotV1, error) {
blob, err := db.Get(append([]byte("XDPoS-"), hash[:]...))
if err != nil {
return nil, err
}
snap := new(SnapshotV1)
if err := json.Unmarshal(blob, snap); err != nil {
return nil, err
}
snap.config = config
snap.sigcache = sigcache
return snap, nil
}
// store inserts the SnapshotV1 into the database.
func (s *SnapshotV1) store(db ethdb.Database) error {
blob, err := json.Marshal(s)
if err != nil {
return err
}
return db.Put(append([]byte("XDPoS-"), s.Hash[:]...), blob)
}
// copy creates a deep copy of the SnapshotV1, though not the individual votes.
func (s *SnapshotV1) copy() *SnapshotV1 {
cpy := &SnapshotV1{
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([]*clique.Vote, len(s.Votes)),
Tally: make(map[common.Address]clique.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 *SnapshotV1) 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 *SnapshotV1) 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] = clique.Tally{Authorize: authorize, Votes: 1}
}
return true
}
// uncast removes a previously cast vote from the tally.
func (s *SnapshotV1) 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 SnapshotV1 by applying the given headers to
// the original one.
func (s *SnapshotV1) apply(headers []*types.Header) (*SnapshotV1, 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, utils.ErrInvalidVotingChain
}
}
if headers[0].Number.Uint64() != s.Number+1 {
return nil, utils.ErrInvalidVotingChain
}
// Iterate through the headers and create a new SnapshotV1
snap := s.copy()
for _, 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]clique.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
}
//FIXME: skip signer checking at this step until a good solution found
//if _, ok := snap.Signers[signer]; !ok {
// return nil, errUnauthorized
//}
//for _, recent := range snap.Recents {
// if recent == signer {
// return nil, errUnauthorized
// }
//}
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[:], utils.NonceAuthVote):
authorize = true
case bytes.Equal(header.Nonce[:], utils.NonceDropVote):
authorize = false
default:
return nil, utils.ErrInvalidVote
}
if snap.cast(header.Coinbase, authorize) {
snap.Votes = append(snap.Votes, &clique.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 *SnapshotV1) GetSigners() []common.Address {
signers := make([]common.Address, 0, len(s.Signers))
for signer := range s.Signers {
signers = append(signers, signer)
}
for i := 0; i < len(signers); i++ {
for j := i + 1; j < len(signers); j++ {
if bytes.Compare(signers[i][:], signers[j][:]) > 0 {
signers[i], signers[j] = signers[j], signers[i]
}
}
}
return signers
}