// removeTransaction is the internal function which implements the public
// RemoveTransaction. See the comment for RemoveTransaction for more details.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *txMemPool) removeTransaction(tx *btcutil.Tx, removeRedeemers bool) {
txHash := tx.Sha()
if removeRedeemers {
// Remove any transactions which rely on this one.
for i := uint32(0); i < uint32(len(tx.MsgTx().TxOut)); i++ {
outpoint := wire.NewOutPoint(txHash, i)
if txRedeemer, exists := mp.outpoints[*outpoint]; exists {
mp.removeTransaction(txRedeemer, true)
}
}
}
// Remove the transaction and mark the referenced outpoints as unspent
// by the pool.
if txDesc, exists := mp.pool[*txHash]; exists {
if mp.cfg.EnableAddrIndex {
mp.removeTransactionFromAddrIndex(tx)
}
for _, txIn := range txDesc.Tx.MsgTx().TxIn {
delete(mp.outpoints, txIn.PreviousOutPoint)
}
delete(mp.pool, *txHash)
atomic.StoreInt64(&mp.lastUpdated, time.Now().Unix())
}
}
// removeTransaction is the internal function which implements the public
// RemoveTransaction. See the comment for RemoveTransaction for more details.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *TxPool) removeTransaction(tx *btcutil.Tx, removeRedeemers bool) {
txHash := tx.Hash()
if removeRedeemers {
// Remove any transactions which rely on this one.
for i := uint32(0); i < uint32(len(tx.MsgTx().TxOut)); i++ {
prevOut := wire.OutPoint{Hash: *txHash, Index: i}
if txRedeemer, exists := mp.outpoints[prevOut]; exists {
mp.removeTransaction(txRedeemer, true)
}
}
}
// Remove the transaction if needed.
if txDesc, exists := mp.pool[*txHash]; exists {
// Remove unconfirmed address index entries associated with the
// transaction if enabled.
if mp.cfg.AddrIndex != nil {
mp.cfg.AddrIndex.RemoveUnconfirmedTx(txHash)
}
// Mark the referenced outpoints as unspent by the pool.
for _, txIn := range txDesc.Tx.MsgTx().TxIn {
delete(mp.outpoints, txIn.PreviousOutPoint)
}
delete(mp.pool, *txHash)
atomic.StoreInt64(&mp.lastUpdated, time.Now().Unix())
}
}
// calcPriority returns a transaction priority given a transaction and the sum
// of each of its input values multiplied by their age (# of confirmations).
// Thus, the final formula for the priority is:
// sum(inputValue * inputAge) / adjustedTxSize
func calcPriority(tx *btcutil.Tx, inputValueAge float64) float64 {
// In order to encourage spending multiple old unspent transaction
// outputs thereby reducing the total set, don't count the constant
// overhead for each input as well as enough bytes of the signature
// script to cover a pay-to-script-hash redemption with a compressed
// pubkey. This makes additional inputs free by boosting the priority
// of the transaction accordingly. No more incentive is given to avoid
// encouraging gaming future transactions through the use of junk
// outputs. This is the same logic used in the reference
// implementation.
//
// The constant overhead for a txin is 41 bytes since the previous
// outpoint is 36 bytes + 4 bytes for the sequence + 1 byte the
// signature script length.
//
// A compressed pubkey pay-to-script-hash redemption with a maximum len
// signature is of the form:
// [OP_DATA_73 <73-byte sig> + OP_DATA_35 + {OP_DATA_33
// <33 byte compresed pubkey> + OP_CHECKSIG}]
//
// Thus 1 + 73 + 1 + 1 + 33 + 1 = 110
overhead := 0
for _, txIn := range tx.MsgTx().TxIn {
// Max inputs + size can't possibly overflow here.
overhead += 41 + minInt(110, len(txIn.SignatureScript))
}
serializedTxSize := tx.MsgTx().SerializeSize()
if overhead >= serializedTxSize {
return 0.0
}
return inputValueAge / float64(serializedTxSize-overhead)
}
// ExtractCoinbaseHeight attempts to extract the height of the block from the
// scriptSig of a coinbase transaction. Coinbase heights are only present in
// blocks of version 2 or later. This was added as part of BIP0034.
func ExtractCoinbaseHeight(coinbaseTx *btcutil.Tx) (int32, error) {
sigScript := coinbaseTx.MsgTx().TxIn[0].SignatureScript
if len(sigScript) < 1 {
str := "the coinbase signature script for blocks of " +
"version %d or greater must start with the " +
"length of the serialized block height"
str = fmt.Sprintf(str, serializedHeightVersion)
return 0, ruleError(ErrMissingCoinbaseHeight, str)
}
serializedLen := int(sigScript[0])
if len(sigScript[1:]) < serializedLen {
str := "the coinbase signature script for blocks of " +
"version %d or greater must start with the " +
"serialized block height"
str = fmt.Sprintf(str, serializedLen)
return 0, ruleError(ErrMissingCoinbaseHeight, str)
}
serializedHeightBytes := make([]byte, 8, 8)
copy(serializedHeightBytes, sigScript[1:serializedLen+1])
serializedHeight := binary.LittleEndian.Uint64(serializedHeightBytes)
return int32(serializedHeight), nil
}
// IsFinalizedTransaction determines whether or not a transaction is finalized.
func IsFinalizedTransaction(tx *btcutil.Tx, blockHeight int32, blockTime time.Time) bool {
msgTx := tx.MsgTx()
// Lock time of zero means the transaction is finalized.
lockTime := msgTx.LockTime
if lockTime == 0 {
return true
}
// The lock time field of a transaction is either a block height at
// which the transaction is finalized or a timestamp depending on if the
// value is before the txscript.LockTimeThreshold. When it is under the
// threshold it is a block height.
blockTimeOrHeight := int64(0)
if lockTime < txscript.LockTimeThreshold {
blockTimeOrHeight = int64(blockHeight)
} else {
blockTimeOrHeight = blockTime.Unix()
}
if int64(lockTime) < blockTimeOrHeight {
return true
}
// At this point, the transaction's lock time hasn't occurred yet, but
// the transaction might still be finalized if the sequence number
// for all transaction inputs is maxed out.
for _, txIn := range msgTx.TxIn {
if txIn.Sequence != math.MaxUint32 {
return false
}
}
return true
}
// ValidateTransactionScripts validates the scripts for the passed transaction
// using multiple goroutines.
func ValidateTransactionScripts(tx *btcutil.Tx, utxoView *UtxoViewpoint, flags txscript.ScriptFlags, sigCache *txscript.SigCache) error {
// Collect all of the transaction inputs and required information for
// validation.
txIns := tx.MsgTx().TxIn
txValItems := make([]*txValidateItem, 0, len(txIns))
for txInIdx, txIn := range txIns {
// Skip coinbases.
if txIn.PreviousOutPoint.Index == math.MaxUint32 {
continue
}
txVI := &txValidateItem{
txInIndex: txInIdx,
txIn: txIn,
tx: tx,
}
txValItems = append(txValItems, txVI)
}
// Validate all of the inputs.
validator := newTxValidator(utxoView, flags, sigCache)
if err := validator.Validate(txValItems); err != nil {
return err
}
return nil
}
// checkInputsStandard performs a series of checks on a transaction's inputs
// to ensure they are "standard". A standard transaction input within the
// context of this function is one whose referenced public key script is of a
// standard form and, for pay-to-script-hash, does not have more than
// maxStandardP2SHSigOps signature operations. However, it should also be noted
// that standard inputs also are those which have a clean stack after execution
// and only contain pushed data in their signature scripts. This function does
// not perform those checks because the script engine already does this more
// accurately and concisely via the txscript.ScriptVerifyCleanStack and
// txscript.ScriptVerifySigPushOnly flags.
func checkInputsStandard(tx *btcutil.Tx, utxoView *blockchain.UtxoViewpoint) error {
// NOTE: The reference implementation also does a coinbase check here,
// but coinbases have already been rejected prior to calling this
// function so no need to recheck.
for i, txIn := range tx.MsgTx().TxIn {
// It is safe to elide existence and index checks here since
// they have already been checked prior to calling this
// function.
prevOut := txIn.PreviousOutPoint
entry := utxoView.LookupEntry(&prevOut.Hash)
originPkScript := entry.PkScriptByIndex(prevOut.Index)
switch txscript.GetScriptClass(originPkScript) {
case txscript.ScriptHashTy:
numSigOps := txscript.GetPreciseSigOpCount(
txIn.SignatureScript, originPkScript, true)
if numSigOps > maxStandardP2SHSigOps {
str := fmt.Sprintf("transaction input #%d has "+
"%d signature operations which is more "+
"than the allowed max amount of %d",
i, numSigOps, maxStandardP2SHSigOps)
return txRuleError(wire.RejectNonstandard, str)
}
case txscript.NonStandardTy:
str := fmt.Sprintf("transaction input #%d has a "+
"non-standard script form", i)
return txRuleError(wire.RejectNonstandard, str)
}
}
return nil
}
// checkSerializedHeight checks if the signature script in the passed
// transaction starts with the serialized block height of wantHeight.
func checkSerializedHeight(coinbaseTx *btcutil.Tx, wantHeight int64) error {
sigScript := coinbaseTx.MsgTx().TxIn[0].SignatureScript
if len(sigScript) < 1 {
str := "the coinbase signature script for blocks of " +
"version %d or greater must start with the " +
"length of the serialized block height"
str = fmt.Sprintf(str, serializedHeightVersion)
return ruleError(ErrMissingCoinbaseHeight, str)
}
serializedLen := int(sigScript[0])
if len(sigScript[1:]) < serializedLen {
str := "the coinbase signature script for blocks of " +
"version %d or greater must start with the " +
"serialized block height"
str = fmt.Sprintf(str, serializedLen)
return ruleError(ErrMissingCoinbaseHeight, str)
}
serializedHeightBytes := make([]byte, 8, 8)
copy(serializedHeightBytes, sigScript[1:serializedLen+1])
serializedHeight := binary.LittleEndian.Uint64(serializedHeightBytes)
if int64(serializedHeight) != wantHeight {
str := fmt.Sprintf("the coinbase signature script serialized "+
"block height is %d when %d was expected",
serializedHeight, wantHeight)
return ruleError(ErrBadCoinbaseHeight, str)
}
return nil
}
// removeTransaction is the internal function which implements the public
// RemoveTransaction. See the comment for RemoveTransaction for more details.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *txMemPool) removeTransaction(tx *btcutil.Tx) {
// Remove any transactions which rely on this one.
txHash := tx.Sha()
for i := uint32(0); i < uint32(len(tx.MsgTx().TxOut)); i++ {
outpoint := wire.NewOutPoint(txHash, i)
if txRedeemer, exists := mp.outpoints[*outpoint]; exists {
mp.removeTransaction(txRedeemer)
}
}
// Remove the transaction and mark the referenced outpoints as unspent
// by the pool.
if txDesc, exists := mp.pool[*txHash]; exists {
if cfg.AddrIndex {
mp.removeTransactionFromAddrIndex(tx)
}
for _, txIn := range txDesc.Tx.MsgTx().TxIn {
delete(mp.outpoints, txIn.PreviousOutPoint)
}
delete(mp.pool, *txHash)
mp.lastUpdated = time.Now()
}
}
func serializeTx(tx *btcutil.Tx) []byte {
var buf bytes.Buffer
err := tx.MsgTx().Serialize(&buf)
if err != nil {
panic(err)
}
return buf.Bytes()
}
// removeOrphanDoubleSpends removes all orphans which spend outputs spent by the
// passed transaction from the orphan pool. Removing those orphans then leads
// to removing all orphans which rely on them, recursively. This is necessary
// when a transaction is added to the main pool because it may spend outputs
// that orphans also spend.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *TxPool) removeOrphanDoubleSpends(tx *btcutil.Tx) {
msgTx := tx.MsgTx()
for _, txIn := range msgTx.TxIn {
for _, orphan := range mp.orphansByPrev[txIn.PreviousOutPoint] {
mp.removeOrphan(orphan, true)
}
}
}
// getUtxo returns a TxOut from Tx and Vout
func (com *Communication) getUtxo(tx *btcutil.Tx,
vout *wire.TxOut, index uint32) *TxOut {
op := wire.NewOutPoint(tx.Sha(), index)
unspent := TxOut{
OutPoint: op,
Amount: btcutil.Amount(vout.Value),
}
return &unspent
}
// ProcessTransaction is the main workhorse for handling insertion of new
// free-standing transactions into the memory pool. It includes functionality
// such as rejecting duplicate transactions, ensuring transactions follow all
// rules, orphan transaction handling, and insertion into the memory pool.
//
// It returns a slice of transactions added to the mempool. When the
// error is nil, the list will include the passed transaction itself along
// with any additional orphan transaactions that were added as a result of
// the passed one being accepted.
//
// This function is safe for concurrent access.
func (mp *TxPool) ProcessTransaction(tx *btcutil.Tx, allowOrphan, rateLimit bool, tag Tag) ([]*TxDesc, error) {
log.Tracef("Processing transaction %v", tx.Hash())
// Protect concurrent access.
mp.mtx.Lock()
defer mp.mtx.Unlock()
// Potentially accept the transaction to the memory pool.
missingParents, txD, err := mp.maybeAcceptTransaction(tx, true, rateLimit,
true)
if err != nil {
return nil, err
}
if len(missingParents) == 0 {
// Accept any orphan transactions that depend on this
// transaction (they may no longer be orphans if all inputs
// are now available) and repeat for those accepted
// transactions until there are no more.
newTxs := mp.processOrphans(tx)
acceptedTxs := make([]*TxDesc, len(newTxs)+1)
// Add the parent transaction first so remote nodes
// do not add orphans.
acceptedTxs[0] = txD
copy(acceptedTxs[1:], newTxs)
return acceptedTxs, nil
}
// The transaction is an orphan (has inputs missing). Reject
// it if the flag to allow orphans is not set.
if !allowOrphan {
// Only use the first missing parent transaction in
// the error message.
//
// NOTE: RejectDuplicate is really not an accurate
// reject code here, but it matches the reference
// implementation and there isn't a better choice due
// to the limited number of reject codes. Missing
// inputs is assumed to mean they are already spent
// which is not really always the case.
str := fmt.Sprintf("orphan transaction %v references "+
"outputs of unknown or fully-spent "+
"transaction %v", tx.Hash(), missingParents[0])
return nil, txRuleError(wire.RejectDuplicate, str)
}
// Potentially add the orphan transaction to the orphan pool.
err = mp.maybeAddOrphan(tx, tag)
if err != nil {
return nil, err
}
return nil, nil
}
// isNonstandardTransaction determines whether a transaction contains any
// scripts which are not one of the standard types.
func isNonstandardTransaction(tx *btcutil.Tx) bool {
// Check all of the output public key scripts for non-standard scripts.
for _, txOut := range tx.MsgTx().TxOut {
scriptClass := txscript.GetScriptClass(txOut.PkScript)
if scriptClass == txscript.NonStandardTy {
return true
}
}
return false
}
// logSkippedDeps logs any dependencies which are also skipped as a result of
// skipping a transaction while generating a block template at the trace level.
func logSkippedDeps(tx *btcutil.Tx, deps map[chainhash.Hash]*txPrioItem) {
if deps == nil {
return
}
for _, item := range deps {
log.Tracef("Skipping tx %s since it depends on %s\n",
item.tx.Hash(), tx.Hash())
}
}
// logSkippedDeps logs any dependencies which are also skipped as a result of
// skipping a transaction while generating a block template at the trace level.
func logSkippedDeps(tx *btcutil.Tx, deps *list.List) {
if deps == nil {
return
}
for e := deps.Front(); e != nil; e = e.Next() {
item := e.Value.(*txPrioItem)
minrLog.Tracef("Skipping tx %s since it depends on %s\n",
item.tx.Sha(), tx.Sha())
}
}
// isNonstandardTransaction determines whether a transaction contains any
// scripts which are not one of the standard types.
func isNonstandardTransaction(tx *btcutil.Tx) bool {
// TODO(davec): Should there be checks for the input signature scripts?
// Check all of the output public key scripts for non-standard scripts.
for _, txOut := range tx.MsgTx().TxOut {
scriptClass := txscript.GetScriptClass(txOut.PkScript)
if scriptClass == txscript.NonStandardTy {
return true
}
}
return false
}
// checkPoolDoubleSpend checks whether or not the passed transaction is
// attempting to spend coins already spent by other transactions in the pool.
// Note it does not check for double spends against transactions already in the
// main chain.
//
// This function MUST be called with the mempool lock held (for reads).
func (mp *txMemPool) checkPoolDoubleSpend(tx *btcutil.Tx) error {
for _, txIn := range tx.MsgTx().TxIn {
if txR, exists := mp.outpoints[txIn.PreviousOutPoint]; exists {
str := fmt.Sprintf("output %v already spent by "+
"transaction %v in the memory pool",
txIn.PreviousOutPoint, txR.Sha())
return txRuleError(wire.RejectDuplicate, str)
}
}
return nil
}
// RemoveDoubleSpends removes all transactions which spend outputs spent by the
// passed transaction from the memory pool. Removing those transactions then
// leads to removing all transactions which rely on them, recursively. This is
// necessary when a block is connected to the main chain because the block may
// contain transactions which were previously unknown to the memory pool.
//
// This function is safe for concurrent access.
func (mp *TxPool) RemoveDoubleSpends(tx *btcutil.Tx) {
// Protect concurrent access.
mp.mtx.Lock()
for _, txIn := range tx.MsgTx().TxIn {
if txRedeemer, ok := mp.outpoints[txIn.PreviousOutPoint]; ok {
if !txRedeemer.Hash().IsEqual(tx.Hash()) {
mp.removeTransaction(txRedeemer, true)
}
}
}
mp.mtx.Unlock()
}
// spendTransaction updates the passed view by marking the inputs to the passed
// transaction as spent. It also adds all outputs in the passed transaction
// which are not provably unspendable as available unspent transaction outputs.
func spendTransaction(utxoView *blockchain.UtxoViewpoint, tx *btcutil.Tx, height int32) error {
for _, txIn := range tx.MsgTx().TxIn {
originHash := &txIn.PreviousOutPoint.Hash
originIndex := txIn.PreviousOutPoint.Index
entry := utxoView.LookupEntry(originHash)
if entry != nil {
entry.SpendOutput(originIndex)
}
}
utxoView.AddTxOuts(tx, height)
return nil
}
// connectTransaction updates the view by adding all new utxos created by the
// passed transaction and marking all utxos that the transactions spend as
// spent. In addition, when the 'stxos' argument is not nil, it will be updated
// to append an entry for each spent txout. An error will be returned if the
// view does not contain the required utxos.
func (view *UtxoViewpoint) connectTransaction(tx *btcutil.Tx, blockHeight int32, stxos *[]spentTxOut) error {
// Coinbase transactions don't have any inputs to spend.
if IsCoinBase(tx) {
// Add the transaction's outputs as available utxos.
view.AddTxOuts(tx, blockHeight)
return nil
}
// Spend the referenced utxos by marking them spent in the view and,
// if a slice was provided for the spent txout details, append an entry
// to it.
for _, txIn := range tx.MsgTx().TxIn {
originIndex := txIn.PreviousOutPoint.Index
entry := view.entries[txIn.PreviousOutPoint.Hash]
// Ensure the referenced utxo exists in the view. This should
// never happen unless there is a bug is introduced in the code.
if entry == nil {
return AssertError(fmt.Sprintf("view missing input %v",
txIn.PreviousOutPoint))
}
entry.SpendOutput(originIndex)
// Don't create the stxo details if not requested.
if stxos == nil {
continue
}
// Populate the stxo details using the utxo entry. When the
// transaction is fully spent, set the additional stxo fields
// accordingly since those details will no longer be available
// in the utxo set.
var stxo = spentTxOut{
compressed: false,
version: entry.Version(),
amount: entry.AmountByIndex(originIndex),
pkScript: entry.PkScriptByIndex(originIndex),
}
if entry.IsFullySpent() {
stxo.height = entry.BlockHeight()
stxo.isCoinBase = entry.IsCoinBase()
}
// Append the entry to the provided spent txouts slice.
*stxos = append(*stxos, stxo)
}
// Add the transaction's outputs as available utxos.
view.AddTxOuts(tx, blockHeight)
return nil
}
// addOrphan adds an orphan transaction to the orphan pool.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *TxPool) addOrphan(tx *btcutil.Tx, tag Tag) {
// Nothing to do if no orphans are allowed.
if mp.cfg.Policy.MaxOrphanTxs <= 0 {
return
}
// Limit the number orphan transactions to prevent memory exhaustion.
// This will periodically remove any expired orphans and evict a random
// orphan if space is still needed.
mp.limitNumOrphans()
mp.orphans[*tx.Hash()] = &orphanTx{
tx: tx,
tag: tag,
expiration: time.Now().Add(orphanTTL),
}
for _, txIn := range tx.MsgTx().TxIn {
if _, exists := mp.orphansByPrev[txIn.PreviousOutPoint]; !exists {
mp.orphansByPrev[txIn.PreviousOutPoint] =
make(map[chainhash.Hash]*btcutil.Tx)
}
mp.orphansByPrev[txIn.PreviousOutPoint][*tx.Hash()] = tx
}
log.Debugf("Stored orphan transaction %v (total: %d)", tx.Hash(),
len(mp.orphans))
}
// removeScriptFromAddrIndex dissociates the address encoded by the
// passed pkScript from the passed tx in our address based tx index.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *txMemPool) removeScriptFromAddrIndex(pkScript []byte, tx *btcutil.Tx) error {
_, addresses, _, err := txscript.ExtractPkScriptAddrs(pkScript,
activeNetParams.Params)
if err != nil {
txmpLog.Errorf("Unable to extract encoded addresses from script "+
"for addrindex (addrindex): %v", err)
return err
}
for _, addr := range addresses {
delete(mp.addrindex[addr.EncodeAddress()], *tx.Sha())
}
return nil
}
// 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,
FeePerKB: fee * 1000 / int64(tx.MsgTx().SerializeSize()),
},
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
}
// CountP2SHSigOps returns the number of signature operations for all input
// transactions which are of the pay-to-script-hash type. This uses the
// precise, signature operation counting mechanism from the script engine which
// requires access to the input transaction scripts.
func CountP2SHSigOps(tx *btcutil.Tx, isCoinBaseTx bool, utxoView *UtxoViewpoint) (int, error) {
// Coinbase transactions have no interesting inputs.
if isCoinBaseTx {
return 0, nil
}
// Accumulate the number of signature operations in all transaction
// inputs.
msgTx := tx.MsgTx()
totalSigOps := 0
for txInIndex, txIn := range msgTx.TxIn {
// Ensure the referenced input transaction is available.
originTxHash := &txIn.PreviousOutPoint.Hash
originTxIndex := txIn.PreviousOutPoint.Index
txEntry := utxoView.LookupEntry(originTxHash)
if txEntry == nil || txEntry.IsOutputSpent(originTxIndex) {
str := fmt.Sprintf("unable to find unspent output "+
"%v referenced from transaction %s:%d",
txIn.PreviousOutPoint, tx.Hash(), txInIndex)
return 0, ruleError(ErrMissingTx, str)
}
// We're only interested in pay-to-script-hash types, so skip
// this input if it's not one.
pkScript := txEntry.PkScriptByIndex(originTxIndex)
if !txscript.IsPayToScriptHash(pkScript) {
continue
}
// Count the precise number of signature operations in the
// referenced public key script.
sigScript := txIn.SignatureScript
numSigOps := txscript.GetPreciseSigOpCount(sigScript, pkScript,
true)
// We could potentially overflow the accumulator so check for
// overflow.
lastSigOps := totalSigOps
totalSigOps += numSigOps
if totalSigOps < lastSigOps {
str := fmt.Sprintf("the public key script from output "+
"%v contains too many signature operations - "+
"overflow", txIn.PreviousOutPoint)
return 0, ruleError(ErrTooManySigOps, str)
}
}
return totalSigOps, nil
}
// matchTxAndUpdate returns true if the bloom filter matches data within the
// passed transaction, otherwise false is returned. If the filter does match
// the passed transaction, it will also update the filter depending on the bloom
// update flags set via the loaded filter if needed.
//
// This function MUST be called with the filter lock held.
func (bf *Filter) matchTxAndUpdate(tx *btcutil.Tx) bool {
// Check if the filter matches the hash of the transaction.
// This is useful for finding transactions when they appear in a block.
matched := bf.matches(tx.Sha()[:])
// Check if the filter matches any data elements in the public key
// scripts of any of the outputs. When it does, add the outpoint that
// matched so transactions which spend from the matched transaction are
// also included in the filter. This removes the burden of updating the
// filter for this scenario from the client. It is also more efficient
// on the network since it avoids the need for another filteradd message
// from the client and avoids some potential races that could otherwise
// occur.
for i, txOut := range tx.MsgTx().TxOut {
pushedData, err := txscript.PushedData(txOut.PkScript)
if err != nil {
continue
}
for _, data := range pushedData {
if !bf.matches(data) {
continue
}
matched = true
bf.maybeAddOutpoint(txOut.PkScript, tx.Sha(), uint32(i))
break
}
}
// Nothing more to do if a match has already been made.
if matched {
return true
}
// At this point, the transaction and none of the data elements in the
// public key scripts of its outputs matched.
// Check if the filter matches any outpoints this transaction spends or
// any any data elements in the signature scripts of any of the inputs.
for _, txin := range tx.MsgTx().TxIn {
if bf.matchesOutPoint(&txin.PreviousOutPoint) {
return true
}
pushedData, err := txscript.PushedData(txin.SignatureScript)
if err != nil {
continue
}
for _, data := range pushedData {
if bf.matches(data) {
return true
}
}
}
return false
}
// FetchTransactionStore fetches the input transactions referenced by the
// passed transaction from the point of view of the end of the main chain. It
// also attempts to fetch the transaction itself so the returned TxStore can be
// examined for duplicate transactions.
func (b *BlockChain) FetchTransactionStore(tx *btcutil.Tx, includeSpent bool) (TxStore, error) {
// Create a set of needed transactions from the transactions referenced
// by the inputs of the passed transaction. Also, add the passed
// transaction itself as a way for the caller to detect duplicates.
txNeededSet := make(map[wire.ShaHash]struct{})
txNeededSet[*tx.Sha()] = struct{}{}
for _, txIn := range tx.MsgTx().TxIn {
txNeededSet[txIn.PreviousOutPoint.Hash] = struct{}{}
}
// Request the input transactions from the point of view of the end of
// the main chain with or without without including fully spent transactions
// in the results.
txStore := fetchTxStoreMain(b.db, txNeededSet, includeSpent)
return txStore, nil
}
// fetchReferencedOutputScripts looks up and returns all the scriptPubKeys
// referenced by inputs of the passed transaction.
//
// This function MUST be called with the mempool lock held (for reads).
func (mp *txMemPool) fetchReferencedOutputScripts(tx *btcutil.Tx) ([][]byte, error) {
txStore, err := mp.fetchInputTransactions(tx, false)
if err != nil || len(txStore) == 0 {
return nil, err
}
previousOutScripts := make([][]byte, 0, len(tx.MsgTx().TxIn))
for _, txIn := range tx.MsgTx().TxIn {
outPoint := txIn.PreviousOutPoint
if txStore[outPoint.Hash].Err == nil {
referencedOutPoint := txStore[outPoint.Hash].Tx.MsgTx().TxOut[outPoint.Index]
previousOutScripts = append(previousOutScripts, referencedOutPoint.PkScript)
}
}
return previousOutScripts, nil
}
// IsCoinBase determines whether or not a transaction is a coinbase. A coinbase
// is a special transaction created by miners that has no inputs. This is
// represented in the block chain by a transaction with a single input that has
// a previous output transaction index set to the maximum value along with a
// zero hash.
func IsCoinBase(tx *btcutil.Tx) bool {
msgTx := tx.MsgTx()
// A coin base must only have one transaction input.
if len(msgTx.TxIn) != 1 {
return false
}
// The previous output of a coin base must have a max value index and
// a zero hash.
prevOut := msgTx.TxIn[0].PreviousOutPoint
if prevOut.Index != math.MaxUint32 || !prevOut.Hash.IsEqual(zeroHash) {
return false
}
return true
}
// indexScriptByAddress alters our address index by indexing the payment address
// encoded by the passed scriptPubKey to the passed transaction.
//
// This function MUST be called with the mempool lock held (for writes).
func (mp *txMemPool) indexScriptAddressToTx(pkScript []byte, tx *btcutil.Tx) error {
_, addresses, _, err := txscript.ExtractPkScriptAddrs(pkScript,
activeNetParams.Params)
if err != nil {
txmpLog.Errorf("Unable to extract encoded addresses from script "+
"for addrindex: %v", err)
return err
}
for _, addr := range addresses {
if mp.addrindex[addr.EncodeAddress()] == nil {
mp.addrindex[addr.EncodeAddress()] = make(map[wire.ShaHash]struct{})
}
mp.addrindex[addr.EncodeAddress()][*tx.Sha()] = struct{}{}
}
return nil
}