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"
    "gopkg.in/fatih/set.v0"
)

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

const txPoolQueueSize = 50

type TxPoolHook chan *types.Transaction
type TxMsg struct{ Tx *types.Transaction }

type stateFn func() *state.StateDB

const (
    minGasPrice = 1000000
)

type TxProcessor interface {
    ProcessTransaction(tx *types.Transaction)
}

// 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 {
    mu sync.RWMutex
    // Queueing channel for reading and writing incoming
    // transactions to
    queueChan chan *types.Transaction
    // Quiting channel
    quit chan bool
    // The state function which will allow us to do some pre checkes
    currentState stateFn
    // The current gas limit function callback
    gasLimit func() *big.Int
    // The actual pool
    txs           map[common.Hash]*types.Transaction
    invalidHashes *set.Set

    queue map[common.Address]types.Transactions

    subscribers []chan TxMsg

    eventMux *event.TypeMux
}

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

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
    }

    // Validate curve param
    v, _, _ := tx.Curve()
    if v > 28 || v < 27 {
        return fmt.Errorf("tx.v != (28 || 27) => %v", v)
    }

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

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

    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(tx)

    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])

    if glog.V(logger.Debug) {
        glog.Infof("(t) %x => %s (%v) %x\n", from, toname, tx.Value, tx.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])
        }
    }
}

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
}

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

    var txs types.Transactions
    for _, ts := range self.queue {
        txs = append(txs, ts...)
    }

    return txs
}

func (self *TxPool) RemoveTransactions(txs types.Transactions) {
    self.mu.Lock()
    defer self.mu.Unlock()

    for _, tx := range txs {
        delete(self.txs, 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(tx *types.Transaction) {
    from, _ := tx.From()
    self.queue[from] = append(self.queue[from], tx)
}

func (pool *TxPool) addTx(tx *types.Transaction) {
    if _, ok := pool.txs[tx.Hash()]; !ok {
        pool.txs[tx.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()
    for address, txs := range pool.queue {
        sort.Sort(types.TxByNonce{txs})

        var (
            nonce = statedb.GetNonce(address)
            start int
        )
        // Clean up the transactions first and determine the start of the nonces
        for _, tx := range txs {
            if tx.Nonce() >= nonce {
                break
            }
            start++
        }
        pool.queue[address] = txs[start:]

        // expected nonce
        enonce := nonce
        for _, tx := range pool.queue[address] {
            // If the expected nonce does not match up with the next one
            // (i.e. a nonce gap), we stop the loop
            if enonce != tx.Nonce() {
                break
            }
            enonce++

            pool.addTx(tx)
        }
        // delete the entire queue entry if it's empty. There's no need to keep it
        if len(pool.queue[address]) == 0 {
            delete(pool.queue, address)
        }
    }
}

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)
        }
    }
}