plugeth/light/txpool.go
bas-vk 4e36b1e3da core: bugfix state change race condition in txpool (#3412)
The transaction pool keeps track of the current nonce in its local pendingState. When a
new block comes in the pendingState is reset. During the reset it fetches multiple times
the current state through the use of the currentState callback. When a second block comes
in during the reset its possible that the state changes during the reset. If that block
holds transactions that are currently in the pool the local pendingState that is used to
determine nonces can get out of sync.
2016-12-10 23:54:58 +01:00

557 lines
17 KiB
Go

// Copyright 2016 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 light
import (
"fmt"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rlp"
"golang.org/x/net/context"
)
// txPermanent is the number of mined blocks after a mined transaction is
// considered permanent and no rollback is expected
var txPermanent = uint64(500)
// TxPool implements the transaction pool for light clients, which keeps track
// of the status of locally created transactions, detecting if they are included
// in a block (mined) or rolled back. There are no queued transactions since we
// always receive all locally signed transactions in the same order as they are
// created.
type TxPool struct {
config *params.ChainConfig
signer types.Signer
quit chan bool
eventMux *event.TypeMux
events event.Subscription
mu sync.RWMutex
chain *LightChain
odr OdrBackend
chainDb ethdb.Database
relay TxRelayBackend
head common.Hash
nonce map[common.Address]uint64 // "pending" nonce
pending map[common.Hash]*types.Transaction // pending transactions by tx hash
mined map[common.Hash][]*types.Transaction // mined transactions by block hash
clearIdx uint64 // earliest block nr that can contain mined tx info
homestead bool
}
// TxRelayBackend provides an interface to the mechanism that forwards transacions
// to the ETH network. The implementations of the functions should be non-blocking.
//
// Send instructs backend to forward new transactions
// NewHead notifies backend about a new head after processed by the tx pool,
// including mined and rolled back transactions since the last event
// Discard notifies backend about transactions that should be discarded either
// because they have been replaced by a re-send or because they have been mined
// long ago and no rollback is expected
type TxRelayBackend interface {
Send(txs types.Transactions)
NewHead(head common.Hash, mined []common.Hash, rollback []common.Hash)
Discard(hashes []common.Hash)
}
// NewTxPool creates a new light transaction pool
func NewTxPool(config *params.ChainConfig, eventMux *event.TypeMux, chain *LightChain, relay TxRelayBackend) *TxPool {
pool := &TxPool{
config: config,
signer: types.HomesteadSigner{},
nonce: make(map[common.Address]uint64),
pending: make(map[common.Hash]*types.Transaction),
mined: make(map[common.Hash][]*types.Transaction),
quit: make(chan bool),
eventMux: eventMux,
events: eventMux.Subscribe(core.ChainHeadEvent{}),
chain: chain,
relay: relay,
odr: chain.Odr(),
chainDb: chain.Odr().Database(),
head: chain.CurrentHeader().Hash(),
clearIdx: chain.CurrentHeader().Number.Uint64(),
}
go pool.eventLoop()
return pool
}
// currentState returns the light state of the current head header
func (pool *TxPool) currentState() *LightState {
return NewLightState(StateTrieID(pool.chain.CurrentHeader()), pool.odr)
}
// GetNonce returns the "pending" nonce of a given address. It always queries
// the nonce belonging to the latest header too in order to detect if another
// client using the same key sent a transaction.
func (pool *TxPool) GetNonce(ctx context.Context, addr common.Address) (uint64, error) {
nonce, err := pool.currentState().GetNonce(ctx, addr)
if err != nil {
return 0, err
}
sn, ok := pool.nonce[addr]
if ok && sn > nonce {
nonce = sn
}
if !ok || sn < nonce {
pool.nonce[addr] = nonce
}
return nonce, nil
}
type txBlockData struct {
BlockHash common.Hash
BlockIndex uint64
Index uint64
}
// storeTxBlockData stores the block position of a mined tx in the local db
func (pool *TxPool) storeTxBlockData(txh common.Hash, tbd txBlockData) {
//fmt.Println("storeTxBlockData", txh, tbd)
data, _ := rlp.EncodeToBytes(tbd)
pool.chainDb.Put(append(txh[:], byte(1)), data)
}
// removeTxBlockData removes the stored block position of a rolled back tx
func (pool *TxPool) removeTxBlockData(txh common.Hash) {
//fmt.Println("removeTxBlockData", txh)
pool.chainDb.Delete(append(txh[:], byte(1)))
}
// txStateChanges stores the recent changes between pending/mined states of
// transactions. True means mined, false means rolled back, no entry means no change
type txStateChanges map[common.Hash]bool
// setState sets the status of a tx to either recently mined or recently rolled back
func (txc txStateChanges) setState(txHash common.Hash, mined bool) {
val, ent := txc[txHash]
if ent && (val != mined) {
delete(txc, txHash)
} else {
txc[txHash] = mined
}
}
// getLists creates lists of mined and rolled back tx hashes
func (txc txStateChanges) getLists() (mined []common.Hash, rollback []common.Hash) {
for hash, val := range txc {
if val {
mined = append(mined, hash)
} else {
rollback = append(rollback, hash)
}
}
return
}
// checkMinedTxs checks newly added blocks for the currently pending transactions
// and marks them as mined if necessary. It also stores block position in the db
// and adds them to the received txStateChanges map.
func (pool *TxPool) checkMinedTxs(ctx context.Context, hash common.Hash, idx uint64, txc txStateChanges) error {
//fmt.Println("checkMinedTxs")
if len(pool.pending) == 0 {
return nil
}
//fmt.Println("len(pool) =", len(pool.pending))
block, err := GetBlock(ctx, pool.odr, hash, idx)
var receipts types.Receipts
if err != nil {
//fmt.Println(err)
return err
}
//fmt.Println("len(block.Transactions()) =", len(block.Transactions()))
list := pool.mined[hash]
for i, tx := range block.Transactions() {
txHash := tx.Hash()
//fmt.Println(" txHash:", txHash)
if tx, ok := pool.pending[txHash]; ok {
//fmt.Println("TX FOUND")
if receipts == nil {
receipts, err = GetBlockReceipts(ctx, pool.odr, hash, idx)
if err != nil {
return err
}
if len(receipts) != len(block.Transactions()) {
panic(nil) // should never happen if hashes did match
}
core.SetReceiptsData(pool.config, block, receipts)
}
//fmt.Println("WriteReceipt", receipts[i].TxHash)
core.WriteReceipt(pool.chainDb, receipts[i])
pool.storeTxBlockData(txHash, txBlockData{hash, idx, uint64(i)})
delete(pool.pending, txHash)
list = append(list, tx)
txc.setState(txHash, true)
}
}
if list != nil {
pool.mined[hash] = list
}
return nil
}
// rollbackTxs marks the transactions contained in recently rolled back blocks
// as rolled back. It also removes block position info from the db and adds them
// to the received txStateChanges map.
func (pool *TxPool) rollbackTxs(hash common.Hash, txc txStateChanges) {
if list, ok := pool.mined[hash]; ok {
for _, tx := range list {
txHash := tx.Hash()
pool.removeTxBlockData(txHash)
pool.pending[txHash] = tx
txc.setState(txHash, false)
}
delete(pool.mined, hash)
}
}
// setNewHead sets a new head header, processing (and rolling back if necessary)
// the blocks since the last known head and returns a txStateChanges map containing
// the recently mined and rolled back transaction hashes. If an error (context
// timeout) occurs during checking new blocks, it leaves the locally known head
// at the latest checked block and still returns a valid txStateChanges, making it
// possible to continue checking the missing blocks at the next chain head event
func (pool *TxPool) setNewHead(ctx context.Context, newHeader *types.Header) (txStateChanges, error) {
txc := make(txStateChanges)
oldh := pool.chain.GetHeaderByHash(pool.head)
newh := newHeader
// find common ancestor, create list of rolled back and new block hashes
var oldHashes, newHashes []common.Hash
for oldh.Hash() != newh.Hash() {
if oldh.Number.Uint64() >= newh.Number.Uint64() {
oldHashes = append(oldHashes, oldh.Hash())
oldh = pool.chain.GetHeader(oldh.ParentHash, oldh.Number.Uint64()-1)
}
if oldh.Number.Uint64() < newh.Number.Uint64() {
newHashes = append(newHashes, newh.Hash())
newh = pool.chain.GetHeader(newh.ParentHash, newh.Number.Uint64()-1)
if newh == nil {
// happens when CHT syncing, nothing to do
newh = oldh
}
}
}
if oldh.Number.Uint64() < pool.clearIdx {
pool.clearIdx = oldh.Number.Uint64()
}
// roll back old blocks
for _, hash := range oldHashes {
pool.rollbackTxs(hash, txc)
}
pool.head = oldh.Hash()
// check mined txs of new blocks (array is in reversed order)
for i := len(newHashes) - 1; i >= 0; i-- {
hash := newHashes[i]
if err := pool.checkMinedTxs(ctx, hash, newHeader.Number.Uint64()-uint64(i), txc); err != nil {
return txc, err
}
pool.head = hash
}
// clear old mined tx entries of old blocks
if idx := newHeader.Number.Uint64(); idx > pool.clearIdx+txPermanent {
idx2 := idx - txPermanent
for i := pool.clearIdx; i < idx2; i++ {
hash := core.GetCanonicalHash(pool.chainDb, i)
if list, ok := pool.mined[hash]; ok {
hashes := make([]common.Hash, len(list))
for i, tx := range list {
hashes[i] = tx.Hash()
}
pool.relay.Discard(hashes)
delete(pool.mined, hash)
}
}
pool.clearIdx = idx2
}
return txc, nil
}
// blockCheckTimeout is the time limit for checking new blocks for mined
// transactions. Checking resumes at the next chain head event if timed out.
const blockCheckTimeout = time.Second * 3
// eventLoop processes chain head events and also notifies the tx relay backend
// about the new head hash and tx state changes
func (pool *TxPool) eventLoop() {
for ev := range pool.events.Chan() {
switch ev.Data.(type) {
case core.ChainHeadEvent:
pool.mu.Lock()
ctx, _ := context.WithTimeout(context.Background(), blockCheckTimeout)
head := pool.chain.CurrentHeader()
txc, _ := pool.setNewHead(ctx, head)
m, r := txc.getLists()
pool.relay.NewHead(pool.head, m, r)
pool.homestead = pool.config.IsHomestead(head.Number)
pool.signer = types.MakeSigner(pool.config, head.Number)
pool.mu.Unlock()
}
}
}
// Stop stops the light transaction pool
func (pool *TxPool) Stop() {
close(pool.quit)
pool.events.Unsubscribe()
glog.V(logger.Info).Infoln("Transaction pool stopped")
}
// Stats returns the number of currently pending (locally created) transactions
func (pool *TxPool) Stats() (pending int) {
pool.mu.RLock()
defer pool.mu.RUnlock()
pending = len(pool.pending)
return
}
// validateTx checks whether a transaction is valid according to the consensus rules.
func (pool *TxPool) validateTx(ctx context.Context, tx *types.Transaction) error {
// Validate sender
var (
from common.Address
err error
)
// Validate the transaction sender and it's sig. Throw
// if the from fields is invalid.
if from, err = types.Sender(pool.signer, tx); err != nil {
return core.ErrInvalidSender
}
// Make sure the account exist. Non existent accounts
// haven't got funds and well therefor never pass.
currentState := pool.currentState()
if h, err := currentState.HasAccount(ctx, from); err == nil {
if !h {
return core.ErrNonExistentAccount
}
} else {
return err
}
// Last but not least check for nonce errors
if n, err := currentState.GetNonce(ctx, from); err == nil {
if n > tx.Nonce() {
return core.ErrNonce
}
} else {
return err
}
// Check the transaction doesn't exceed the current
// block limit gas.
header := pool.chain.GetHeaderByHash(pool.head)
if header.GasLimit.Cmp(tx.Gas()) < 0 {
return core.ErrGasLimit
}
// Transactions can't be negative. This may never happen
// using RLP decoded transactions but may occur if you create
// a transaction using the RPC for example.
if tx.Value().Cmp(common.Big0) < 0 {
return core.ErrNegativeValue
}
// Transactor should have enough funds to cover the costs
// cost == V + GP * GL
if b, err := currentState.GetBalance(ctx, from); err == nil {
if b.Cmp(tx.Cost()) < 0 {
return core.ErrInsufficientFunds
}
} else {
return err
}
// Should supply enough intrinsic gas
if tx.Gas().Cmp(core.IntrinsicGas(tx.Data(), tx.To() == nil, pool.homestead)) < 0 {
return core.ErrIntrinsicGas
}
return nil
}
// add validates a new transaction and sets its state pending if processable.
// It also updates the locally stored nonce if necessary.
func (self *TxPool) add(ctx context.Context, tx *types.Transaction) error {
hash := tx.Hash()
if self.pending[hash] != nil {
return fmt.Errorf("Known transaction (%x)", hash[:4])
}
err := self.validateTx(ctx, tx)
if err != nil {
return err
}
if _, ok := self.pending[hash]; !ok {
self.pending[hash] = tx
nonce := tx.Nonce() + 1
addr, _ := types.Sender(self.signer, tx)
if nonce > self.nonce[addr] {
self.nonce[addr] = nonce
}
// Notify the subscribers. This event is posted in a goroutine
// because it's possible that somewhere during the post "Remove transaction"
// gets called which will then wait for the global tx pool lock and deadlock.
go self.eventMux.Post(core.TxPreEvent{Tx: tx})
}
if glog.V(logger.Debug) {
var toname string
if to := tx.To(); to != nil {
toname = common.Bytes2Hex(to[:4])
} else {
toname = "[NEW_CONTRACT]"
}
// we can ignore the error here because From is
// verified in ValidateTransaction.
f, _ := types.Sender(self.signer, tx)
from := common.Bytes2Hex(f[:4])
glog.Infof("(t) %x => %s (%v) %x\n", from, toname, tx.Value, hash)
}
return nil
}
// Add adds a transaction to the pool if valid and passes it to the tx relay
// backend
func (self *TxPool) Add(ctx context.Context, tx *types.Transaction) error {
self.mu.Lock()
defer self.mu.Unlock()
data, err := rlp.EncodeToBytes(tx)
if err != nil {
return err
}
if err := self.add(ctx, tx); err != nil {
return err
}
//fmt.Println("Send", tx.Hash())
self.relay.Send(types.Transactions{tx})
self.chainDb.Put(tx.Hash().Bytes(), data)
return nil
}
// AddTransactions adds all valid transactions to the pool and passes them to
// the tx relay backend
func (self *TxPool) AddBatch(ctx context.Context, txs []*types.Transaction) {
self.mu.Lock()
defer self.mu.Unlock()
var sendTx types.Transactions
for _, tx := range txs {
if err := self.add(ctx, tx); err != nil {
glog.V(logger.Debug).Infoln("tx error:", err)
} else {
sendTx = append(sendTx, tx)
h := tx.Hash()
glog.V(logger.Debug).Infof("tx %x\n", h[:4])
}
}
if len(sendTx) > 0 {
self.relay.Send(sendTx)
}
}
// GetTransaction returns a transaction if it is contained in the pool
// and nil otherwise.
func (tp *TxPool) GetTransaction(hash common.Hash) *types.Transaction {
// check the txs first
if tx, ok := tp.pending[hash]; ok {
return tx
}
return nil
}
// GetTransactions returns all currently processable transactions.
// The returned slice may be modified by the caller.
func (self *TxPool) GetTransactions() (txs types.Transactions, err error) {
self.mu.RLock()
defer self.mu.RUnlock()
txs = make(types.Transactions, len(self.pending))
i := 0
for _, tx := range self.pending {
txs[i] = tx
i++
}
return txs, nil
}
// Content retrieves the data content of the transaction pool, returning all the
// pending as well as queued transactions, grouped by account and nonce.
func (self *TxPool) Content() (map[common.Address]types.Transactions, map[common.Address]types.Transactions) {
self.mu.RLock()
defer self.mu.RUnlock()
// Retrieve all the pending transactions and sort by account and by nonce
pending := make(map[common.Address]types.Transactions)
for _, tx := range self.pending {
account, _ := types.Sender(self.signer, tx)
pending[account] = append(pending[account], tx)
}
// There are no queued transactions in a light pool, just return an empty map
queued := make(map[common.Address]types.Transactions)
return pending, queued
}
// RemoveTransactions removes all given transactions from the pool.
func (self *TxPool) RemoveTransactions(txs types.Transactions) {
self.mu.Lock()
defer self.mu.Unlock()
var hashes []common.Hash
for _, tx := range txs {
//self.RemoveTx(tx.Hash())
hash := tx.Hash()
delete(self.pending, hash)
self.chainDb.Delete(hash[:])
hashes = append(hashes, hash)
}
self.relay.Discard(hashes)
}
// RemoveTx removes the transaction with the given hash from the pool.
func (pool *TxPool) RemoveTx(hash common.Hash) {
pool.mu.Lock()
defer pool.mu.Unlock()
// delete from pending pool
delete(pool.pending, hash)
pool.chainDb.Delete(hash[:])
pool.relay.Discard([]common.Hash{hash})
}