path: root/core/transaction_pool.go

package core

import (
    "errors"
    "fmt"
    "math/big"
    "sort"
    "sync"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/event"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
)

var (
    ErrInvalidSender      = errors.New("Invalid sender")
    ErrNonce              = errors.New("Nonce too low")
    ErrBalance            = errors.New("Insufficient balance")
    ErrNonExistentAccount = errors.New("Account does not exist or account balance too low")
    ErrInsufficientFunds  = errors.New("Insufficient funds for gas * price + value")
    ErrIntrinsicGas       = errors.New("Intrinsic gas too low")
    ErrGasLimit           = errors.New("Exceeds block gas limit")
    ErrNegativeValue      = errors.New("Negative value")
)

type stateFn func() *state.StateDB

// The tx pool a thread safe transaction pool handler. In order to
// guarantee a non blocking pool we use a queue channel which can be
// independently read without needing access to the actual pool.
type TxPool struct {
    quit         chan bool       // Quiting channel
    currentState stateFn         // The state function which will allow us to do some pre checkes
    gasLimit     func() *big.Int // The current gas limit function callback
    eventMux     *event.TypeMux

    mu    sync.RWMutex
    txs   map[common.Hash]*types.Transaction // The actual pool
    queue map[common.Address]map[common.Hash]*types.Transaction
}

func NewTxPool(eventMux *event.TypeMux, currentStateFn stateFn, gasLimitFn func() *big.Int) *TxPool {
    return &TxPool{
        txs:          make(map[common.Hash]*types.Transaction),
        queue:        make(map[common.Address]map[common.Hash]*types.Transaction),
        quit:         make(chan bool),
        eventMux:     eventMux,
        currentState: currentStateFn,
        gasLimit:     gasLimitFn,
    }
}

func (pool *TxPool) Start() {
    // Queue timer will tick so we can attempt to move items from the queue to the
    // main transaction pool.
    queueTimer := time.NewTicker(300 * time.Millisecond)
    // Removal timer will tick and attempt to remove bad transactions (account.nonce>tx.nonce)
    removalTimer := time.NewTicker(1 * time.Second)
done:
    for {
        select {
        case <-queueTimer.C:
            pool.checkQueue()
        case <-removalTimer.C:
            pool.validatePool()
        case <-pool.quit:
            break done
        }
    }
}

func (pool *TxPool) ValidateTransaction(tx *types.Transaction) error {
    // Validate sender
    var (
        from common.Address
        err  error
    )

    if from, err = tx.From(); err != nil {
        return ErrInvalidSender
    }

    if !pool.currentState().HasAccount(from) {
        return ErrNonExistentAccount
    }

    if pool.gasLimit().Cmp(tx.GasLimit) < 0 {
        return ErrGasLimit
    }

    if tx.Amount.Cmp(common.Big0) < 0 {
        return ErrNegativeValue
    }

    total := new(big.Int).Mul(tx.Price, tx.GasLimit)
    total.Add(total, tx.Value())
    if pool.currentState().GetBalance(from).Cmp(total) < 0 {
        return ErrInsufficientFunds
    }

    if tx.GasLimit.Cmp(IntrinsicGas(tx)) < 0 {
        return ErrIntrinsicGas
    }

    if pool.currentState().GetNonce(from) > tx.Nonce() {
        return ErrNonce
    }

    return nil
}

func (self *TxPool) add(tx *types.Transaction) error {
    hash := tx.Hash()

    /* XXX I'm unsure about this. This is extremely dangerous and may result
     in total black listing of certain transactions
    if self.invalidHashes.Has(hash) {
        return fmt.Errorf("Invalid transaction (%x)", hash[:4])
    }
    */
    if self.txs[hash] != nil {
        return fmt.Errorf("Known transaction (%x)", hash[:4])
    }
    err := self.ValidateTransaction(tx)
    if err != nil {
        return err
    }
    self.queueTx(hash, 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, _ := tx.From()
        from := common.Bytes2Hex(f[:4])
        glog.Infof("(t) %x => %s (%v) %x\n", from, toname, tx.Value, hash)
    }

    return nil
}

func (self *TxPool) Size() int {
    return len(self.txs)
}

func (self *TxPool) Add(tx *types.Transaction) error {
    self.mu.Lock()
    defer self.mu.Unlock()

    return self.add(tx)
}

func (self *TxPool) AddTransactions(txs []*types.Transaction) {
    self.mu.Lock()
    defer self.mu.Unlock()

    for _, tx := range txs {
        if err := self.add(tx); err != nil {
            glog.V(logger.Debug).Infoln("tx error:", err)
        } else {
            h := tx.Hash()
            glog.V(logger.Debug).Infof("tx %x\n", h[:4])
        }
    }
}

// GetTransaction allows you to check the pending and queued transaction in the
// transaction pool.
// It has two stategies, first check the pool (map) then check the queue
func (tp *TxPool) GetTransaction(hash common.Hash) *types.Transaction {
    // check the txs first
    if tx, ok := tp.txs[hash]; ok {
        return tx
    }
    // check queue
    for _, txs := range tp.queue {
        if tx, ok := txs[hash]; ok {
            return tx
        }
    }
    return nil
}

func (self *TxPool) GetTransactions() (txs types.Transactions) {
    self.mu.RLock()
    defer self.mu.RUnlock()

    txs = make(types.Transactions, self.Size())
    i := 0
    for _, tx := range self.txs {
        txs[i] = tx
        i++
    }
    return txs
}

func (self *TxPool) GetQueuedTransactions() types.Transactions {
    self.mu.RLock()
    defer self.mu.RUnlock()

    var ret types.Transactions
    for _, txs := range self.queue {
        for _, tx := range txs {
            ret = append(ret, tx)
        }
    }
    sort.Sort(types.TxByNonce{ret})
    return ret
}

func (self *TxPool) RemoveTransactions(txs types.Transactions) {
    self.mu.Lock()
    defer self.mu.Unlock()
    for _, tx := range txs {
        self.removeTx(tx.Hash())
    }
}

func (pool *TxPool) Flush() {
    pool.txs = make(map[common.Hash]*types.Transaction)
}

func (pool *TxPool) Stop() {
    pool.Flush()
    close(pool.quit)

    glog.V(logger.Info).Infoln("TX Pool stopped")
}

func (self *TxPool) queueTx(hash common.Hash, tx *types.Transaction) {
    from, _ := tx.From() // already validated
    if self.queue[from] == nil {
        self.queue[from] = make(map[common.Hash]*types.Transaction)
    }
    self.queue[from][hash] = tx
}

func (pool *TxPool) addTx(hash common.Hash, tx *types.Transaction) {
    if _, ok := pool.txs[hash]; !ok {
        pool.txs[hash] = tx
        // 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 pool.eventMux.Post(TxPreEvent{tx})
    }
}

// check queue will attempt to insert
func (pool *TxPool) checkQueue() {
    pool.mu.Lock()
    defer pool.mu.Unlock()

    statedb := pool.currentState()
    var addq txQueue
    for address, txs := range pool.queue {
        curnonce := statedb.GetNonce(address)
        addq := addq[:0]
        for hash, tx := range txs {
            if tx.AccountNonce < curnonce {
                // Drop queued transactions whose nonce is lower than
                // the account nonce because they have been processed.
                delete(txs, hash)
            } else {
                // Collect the remaining transactions for the next pass.
                addq = append(addq, txQueueEntry{hash, tx})
            }
        }
        // Find the next consecutive nonce range starting at the
        // current account nonce.
        sort.Sort(addq)
        for _, e := range addq {
            if e.AccountNonce != curnonce {
                break
            }
            curnonce++
            delete(txs, e.hash)
            pool.addTx(e.hash, e.Transaction)
        }
        // Delete the entire queue entry if it became empty.
        if len(txs) == 0 {
            delete(pool.queue, address)
        }
    }
}

func (pool *TxPool) removeTx(hash common.Hash) {
    // delete from pending pool
    delete(pool.txs, hash)
    // delete from queue
    for address, txs := range pool.queue {
        if _, ok := txs[hash]; ok {
            if len(txs) == 1 {
                // if only one tx, remove entire address entry.
                delete(pool.queue, address)
            } else {
                delete(txs, hash)
            }
            break
        }
    }
}

func (pool *TxPool) validatePool() {
    pool.mu.Lock()
    defer pool.mu.Unlock()

    for hash, tx := range pool.txs {
        if err := pool.ValidateTransaction(tx); err != nil {
            if glog.V(logger.Info) {
                glog.Infof("removed tx (%x) from pool: %v\n", hash[:4], err)
            }
            delete(pool.txs, hash)
        }
    }
}

type txQueue []txQueueEntry

type txQueueEntry struct {
    hash common.Hash
    *types.Transaction
}

func (q txQueue) Len() int           { return len(q) }
func (q txQueue) Swap(i, j int)      { q[i], q[j] = q[j], q[i] }
func (q txQueue) Less(i, j int) bool { return q[i].AccountNonce < q[j].AccountNonce }