// addTransaction adds the passed transaction to the memory pool. It should
// not be called directly as it doesn't perform any validation. This is a
// helper for maybeAcceptTransaction.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *TxPool) addTransaction(utxoView *blockchain.UtxoViewpoint, tx *btcutil.Tx, height int32, fee int64) *TxDesc {
// Add the transaction to the pool and mark the referenced outpoints
// as spent by the pool.
txD := &TxDesc{
TxDesc: mining.TxDesc{
Tx: tx,
Added: time.Now(),
Height: height,
Fee: fee,
},
StartingPriority: mining.CalcPriority(tx.MsgTx(), utxoView, height),
}
mp.pool[*tx.Hash()] = txD
for _, txIn := range tx.MsgTx().TxIn {
mp.outpoints[txIn.PreviousOutPoint] = tx
}
atomic.StoreInt64(&mp.lastUpdated, time.Now().Unix())
// Add unconfirmed address index entries associated with the transaction
// if enabled.
if mp.cfg.AddrIndex != nil {
mp.cfg.AddrIndex.AddUnconfirmedTx(tx, utxoView)
}
return txD
}
// RawMempoolVerbose returns all of the entries in the mempool as a fully
// populated btcjson result.
//
// This function is safe for concurrent access.
func (mp *TxPool) RawMempoolVerbose() map[string]*btcjson.GetRawMempoolVerboseResult {
mp.mtx.RLock()
defer mp.mtx.RUnlock()
result := make(map[string]*btcjson.GetRawMempoolVerboseResult,
len(mp.pool))
bestHeight := mp.cfg.BestHeight()
for _, desc := range mp.pool {
// Calculate the current priority based on the inputs to
// the transaction. Use zero if one or more of the
// input transactions can't be found for some reason.
tx := desc.Tx
var currentPriority float64
utxos, err := mp.fetchInputUtxos(tx)
if err == nil {
currentPriority = mining.CalcPriority(tx.MsgTx(), utxos,
bestHeight+1)
}
mpd := &btcjson.GetRawMempoolVerboseResult{
Size: int32(tx.MsgTx().SerializeSize()),
Fee: btcutil.Amount(desc.Fee).ToBTC(),
Time: desc.Added.Unix(),
Height: int64(desc.Height),
StartingPriority: desc.StartingPriority,
CurrentPriority: currentPriority,
Depends: make([]string, 0),
}
for _, txIn := range tx.MsgTx().TxIn {
hash := &txIn.PreviousOutPoint.Hash
if mp.haveTransaction(hash) {
mpd.Depends = append(mpd.Depends,
hash.String())
}
}
result[tx.Hash().String()] = mpd
}
return result
}
// maybeAcceptTransaction is the internal function which implements the public
// MaybeAcceptTransaction. See the comment for MaybeAcceptTransaction for
// more details.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *TxPool) maybeAcceptTransaction(tx *btcutil.Tx, isNew, rateLimit, rejectDupOrphans bool) ([]*chainhash.Hash, *TxDesc, error) {
txHash := tx.Hash()
// Don't accept the transaction if it already exists in the pool. This
// applies to orphan transactions as well when the reject duplicate
// orphans flag is set. This check is intended to be a quick check to
// weed out duplicates.
if mp.isTransactionInPool(txHash) || (rejectDupOrphans &&
mp.isOrphanInPool(txHash)) {
str := fmt.Sprintf("already have transaction %v", txHash)
return nil, nil, txRuleError(wire.RejectDuplicate, str)
}
// Perform preliminary sanity checks on the transaction. This makes
// use of blockchain which contains the invariant rules for what
// transactions are allowed into blocks.
err := blockchain.CheckTransactionSanity(tx)
if err != nil {
if cerr, ok := err.(blockchain.RuleError); ok {
return nil, nil, chainRuleError(cerr)
}
return nil, nil, err
}
// A standalone transaction must not be a coinbase transaction.
if blockchain.IsCoinBase(tx) {
str := fmt.Sprintf("transaction %v is an individual coinbase",
txHash)
return nil, nil, txRuleError(wire.RejectInvalid, str)
}
// Don't accept transactions with a lock time after the maximum int32
// value for now. This is an artifact of older bitcoind clients which
// treated this field as an int32 and would treat anything larger
// incorrectly (as negative).
if tx.MsgTx().LockTime > math.MaxInt32 {
str := fmt.Sprintf("transaction %v has a lock time after "+
"2038 which is not accepted yet", txHash)
return nil, nil, txRuleError(wire.RejectNonstandard, str)
}
// Get the current height of the main chain. A standalone transaction
// will be mined into the next block at best, so its height is at least
// one more than the current height.
bestHeight := mp.cfg.BestHeight()
nextBlockHeight := bestHeight + 1
medianTimePast := mp.cfg.MedianTimePast()
// Don't allow non-standard transactions if the network parameters
// forbid their acceptance.
if !mp.cfg.Policy.AcceptNonStd {
err = checkTransactionStandard(tx, nextBlockHeight,
medianTimePast, mp.cfg.Policy.MinRelayTxFee,
mp.cfg.Policy.MaxTxVersion)
if err != nil {
// Attempt to extract a reject code from the error so
// it can be retained. When not possible, fall back to
// a non standard error.
rejectCode, found := extractRejectCode(err)
if !found {
rejectCode = wire.RejectNonstandard
}
str := fmt.Sprintf("transaction %v is not standard: %v",
txHash, err)
return nil, nil, txRuleError(rejectCode, str)
}
}
// The transaction may not use any of the same outputs as other
// transactions already in the pool as that would ultimately result in a
// double spend. This check is intended to be quick and therefore only
// detects double spends within the transaction pool itself. The
// transaction could still be double spending coins from the main chain
// at this point. There is a more in-depth check that happens later
// after fetching the referenced transaction inputs from the main chain
// which examines the actual spend data and prevents double spends.
err = mp.checkPoolDoubleSpend(tx)
if err != nil {
return nil, nil, err
}
// Fetch all of the unspent transaction outputs referenced by the inputs
// to this transaction. This function also attempts to fetch the
// transaction itself to be used for detecting a duplicate transaction
// without needing to do a separate lookup.
utxoView, err := mp.fetchInputUtxos(tx)
if err != nil {
if cerr, ok := err.(blockchain.RuleError); ok {
return nil, nil, chainRuleError(cerr)
}
return nil, nil, err
}
// Don't allow the transaction if it exists in the main chain and is not
// not already fully spent.
txEntry := utxoView.LookupEntry(txHash)
if txEntry != nil && !txEntry.IsFullySpent() {
return nil, nil, txRuleError(wire.RejectDuplicate,
"transaction already exists")
}
delete(utxoView.Entries(), *txHash)
// Transaction is an orphan if any of the referenced input transactions
// don't exist. Adding orphans to the orphan pool is not handled by
// this function, and the caller should use maybeAddOrphan if this
// behavior is desired.
var missingParents []*chainhash.Hash
for originHash, entry := range utxoView.Entries() {
if entry == nil || entry.IsFullySpent() {
// Must make a copy of the hash here since the iterator
// is replaced and taking its address directly would
// result in all of the entries pointing to the same
// memory location and thus all be the final hash.
hashCopy := originHash
missingParents = append(missingParents, &hashCopy)
}
}
if len(missingParents) > 0 {
return missingParents, nil, nil
}
// Don't allow the transaction into the mempool unless its sequence
// lock is active, meaning that it'll be allowed into the next block
// with respect to its defined relative lock times.
sequenceLock, err := mp.cfg.CalcSequenceLock(tx, utxoView)
if err != nil {
if cerr, ok := err.(blockchain.RuleError); ok {
return nil, nil, chainRuleError(cerr)
}
return nil, nil, err
}
if !blockchain.SequenceLockActive(sequenceLock, nextBlockHeight,
medianTimePast) {
return nil, nil, txRuleError(wire.RejectNonstandard,
"transaction's sequence locks on inputs not met")
}
// Perform several checks on the transaction inputs using the invariant
// rules in blockchain for what transactions are allowed into blocks.
// Also returns the fees associated with the transaction which will be
// used later.
txFee, err := blockchain.CheckTransactionInputs(tx, nextBlockHeight,
utxoView, mp.cfg.ChainParams)
if err != nil {
if cerr, ok := err.(blockchain.RuleError); ok {
return nil, nil, chainRuleError(cerr)
}
return nil, nil, err
}
// Don't allow transactions with non-standard inputs if the network
// parameters forbid their acceptance.
if !mp.cfg.Policy.AcceptNonStd {
err := checkInputsStandard(tx, utxoView)
if err != nil {
// Attempt to extract a reject code from the error so
// it can be retained. When not possible, fall back to
// a non standard error.
rejectCode, found := extractRejectCode(err)
if !found {
rejectCode = wire.RejectNonstandard
}
str := fmt.Sprintf("transaction %v has a non-standard "+
"input: %v", txHash, err)
return nil, nil, txRuleError(rejectCode, str)
}
}
// NOTE: if you modify this code to accept non-standard transactions,
// you should add code here to check that the transaction does a
// reasonable number of ECDSA signature verifications.
// Don't allow transactions with an excessive number of signature
// operations which would result in making it impossible to mine. Since
// the coinbase address itself can contain signature operations, the
// maximum allowed signature operations per transaction is less than
// the maximum allowed signature operations per block.
numSigOps, err := blockchain.CountP2SHSigOps(tx, false, utxoView)
if err != nil {
if cerr, ok := err.(blockchain.RuleError); ok {
return nil, nil, chainRuleError(cerr)
}
return nil, nil, err
}
numSigOps += blockchain.CountSigOps(tx)
if numSigOps > mp.cfg.Policy.MaxSigOpsPerTx {
str := fmt.Sprintf("transaction %v has too many sigops: %d > %d",
txHash, numSigOps, mp.cfg.Policy.MaxSigOpsPerTx)
return nil, nil, txRuleError(wire.RejectNonstandard, str)
}
// Don't allow transactions with fees too low to get into a mined block.
//
// Most miners allow a free transaction area in blocks they mine to go
// alongside the area used for high-priority transactions as well as
// transactions with fees. A transaction size of up to 1000 bytes is
// considered safe to go into this section. Further, the minimum fee
// calculated below on its own would encourage several small
// transactions to avoid fees rather than one single larger transaction
// which is more desirable. Therefore, as long as the size of the
// transaction does not exceeed 1000 less than the reserved space for
// high-priority transactions, don't require a fee for it.
serializedSize := int64(tx.MsgTx().SerializeSize())
minFee := calcMinRequiredTxRelayFee(serializedSize,
mp.cfg.Policy.MinRelayTxFee)
if serializedSize >= (DefaultBlockPrioritySize-1000) && txFee < minFee {
str := fmt.Sprintf("transaction %v has %d fees which is under "+
"the required amount of %d", txHash, txFee,
minFee)
return nil, nil, txRuleError(wire.RejectInsufficientFee, str)
}
// Require that free transactions have sufficient priority to be mined
// in the next block. Transactions which are being added back to the
// memory pool from blocks that have been disconnected during a reorg
// are exempted.
if isNew && !mp.cfg.Policy.DisableRelayPriority && txFee < minFee {
currentPriority := mining.CalcPriority(tx.MsgTx(), utxoView,
nextBlockHeight)
if currentPriority <= mining.MinHighPriority {
str := fmt.Sprintf("transaction %v has insufficient "+
"priority (%g <= %g)", txHash,
currentPriority, mining.MinHighPriority)
return nil, nil, txRuleError(wire.RejectInsufficientFee, str)
}
}
// Free-to-relay transactions are rate limited here to prevent
// penny-flooding with tiny transactions as a form of attack.
if rateLimit && txFee < minFee {
nowUnix := time.Now().Unix()
// Decay passed data with an exponentially decaying ~10 minute
// window - matches bitcoind handling.
mp.pennyTotal *= math.Pow(1.0-1.0/600.0,
float64(nowUnix-mp.lastPennyUnix))
mp.lastPennyUnix = nowUnix
// Are we still over the limit?
if mp.pennyTotal >= mp.cfg.Policy.FreeTxRelayLimit*10*1000 {
str := fmt.Sprintf("transaction %v has been rejected "+
"by the rate limiter due to low fees", txHash)
return nil, nil, txRuleError(wire.RejectInsufficientFee, str)
}
oldTotal := mp.pennyTotal
mp.pennyTotal += float64(serializedSize)
log.Tracef("rate limit: curTotal %v, nextTotal: %v, "+
"limit %v", oldTotal, mp.pennyTotal,
mp.cfg.Policy.FreeTxRelayLimit*10*1000)
}
// Verify crypto signatures for each input and reject the transaction if
// any don't verify.
err = blockchain.ValidateTransactionScripts(tx, utxoView,
txscript.StandardVerifyFlags, mp.cfg.SigCache)
if err != nil {
if cerr, ok := err.(blockchain.RuleError); ok {
return nil, nil, chainRuleError(cerr)
}
return nil, nil, err
}
// Add to transaction pool.
txD := mp.addTransaction(utxoView, tx, bestHeight, txFee)
log.Debugf("Accepted transaction %v (pool size: %v)", txHash,
len(mp.pool))
return nil, txD, nil
}