// 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, txStore TxStore) (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 _, txIn := range msgTx.TxIn {
// Ensure the referenced input transaction is available.
txInHash := &txIn.PreviousOutPoint.Hash
originTx, exists := txStore[*txInHash]
if !exists || originTx.Err != nil || originTx.Tx == nil {
str := fmt.Sprintf("unable to find input transaction "+
"%v referenced from transaction %v", txInHash,
tx.Sha())
return 0, ruleError(ErrMissingTx, str)
}
originMsgTx := originTx.Tx.MsgTx()
// Ensure the output index in the referenced transaction is
// available.
originTxIndex := txIn.PreviousOutPoint.Index
if originTxIndex >= uint32(len(originMsgTx.TxOut)) {
str := fmt.Sprintf("out of bounds input index %d in "+
"transaction %v referenced from transaction %v",
originTxIndex, txInHash, tx.Sha())
return 0, ruleError(ErrBadTxInput, str)
}
// We're only interested in pay-to-script-hash types, so skip
// this input if it's not one.
pkScript := originMsgTx.TxOut[originTxIndex].PkScript
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 index %d in transaction %v contains "+
"too many signature operations - overflow",
originTxIndex, txInHash)
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().Bytes())
// 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
}
// 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())
}
}
// 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
}
// spendTransaction updates the passed transaction store by marking the inputs
// to the passed transaction as spent. It also adds the passed transaction to
// the store at the provided height.
func spendTransaction(txStore blockchain.TxStore, tx *btcutil.Tx, height int32) error {
for _, txIn := range tx.MsgTx().TxIn {
originHash := &txIn.PreviousOutPoint.Hash
originIndex := txIn.PreviousOutPoint.Index
if originTx, exists := txStore[*originHash]; exists {
originTx.Spent[originIndex] = true
}
}
txStore[*tx.Sha()] = &blockchain.TxData{
Tx: tx,
Hash: tx.Sha(),
BlockHeight: height,
Spent: make([]bool, len(tx.MsgTx().TxOut)),
Err: nil,
}
return nil
}
// CheckTransactionInputs performs a series of checks on the inputs to a
// transaction to ensure they are valid. An example of some of the checks
// include verifying all inputs exist, ensuring the coinbase seasoning
// requirements are met, detecting double spends, validating all values and fees
// are in the legal range and the total output amount doesn't exceed the input
// amount, and verifying the signatures to prove the spender was the owner of
// the bitcoins and therefore allowed to spend them. As it checks the inputs,
// it also calculates the total fees for the transaction and returns that value.
func CheckTransactionInputs(tx *btcutil.Tx, txHeight int32, txStore TxStore) (int64, error) {
// Coinbase transactions have no inputs.
if IsCoinBase(tx) {
return 0, nil
}
txHash := tx.Sha()
var totalSatoshiIn int64
for _, txIn := range tx.MsgTx().TxIn {
// Ensure the input is available.
txInHash := &txIn.PreviousOutPoint.Hash
originTx, exists := txStore[*txInHash]
if !exists || originTx.Err != nil || originTx.Tx == nil {
str := fmt.Sprintf("unable to find input transaction "+
"%v for transaction %v", txInHash, txHash)
return 0, ruleError(ErrMissingTx, str)
}
// Ensure the transaction is not spending coins which have not
// yet reached the required coinbase maturity.
if IsCoinBase(originTx.Tx) {
originHeight := originTx.BlockHeight
blocksSincePrev := txHeight - originHeight
if blocksSincePrev < coinbaseMaturity {
str := fmt.Sprintf("tried to spend coinbase "+
"transaction %v from height %v at "+
"height %v before required maturity "+
"of %v blocks", txInHash, originHeight,
txHeight, coinbaseMaturity)
return 0, ruleError(ErrImmatureSpend, str)
}
}
// Ensure the transaction is not double spending coins.
originTxIndex := txIn.PreviousOutPoint.Index
if originTxIndex >= uint32(len(originTx.Spent)) {
str := fmt.Sprintf("out of bounds input index %d in "+
"transaction %v referenced from transaction %v",
originTxIndex, txInHash, txHash)
return 0, ruleError(ErrBadTxInput, str)
}
if originTx.Spent[originTxIndex] {
str := fmt.Sprintf("transaction %v tried to double "+
"spend output %v", txHash, txIn.PreviousOutPoint)
return 0, ruleError(ErrDoubleSpend, str)
}
// Ensure the transaction amounts are in range. Each of the
// output values of the input transactions must not be negative
// or more than the max allowed per transaction. All amounts in
// a transaction are in a unit value known as a satoshi. One
// bitcoin is a quantity of satoshi as defined by the
// SatoshiPerBitcoin constant.
originTxSatoshi := originTx.Tx.MsgTx().TxOut[originTxIndex].Value
if originTxSatoshi < 0 {
str := fmt.Sprintf("transaction output has negative "+
"value of %v", originTxSatoshi)
return 0, ruleError(ErrBadTxOutValue, str)
}
if originTxSatoshi > btcutil.MaxSatoshi {
str := fmt.Sprintf("transaction output value of %v is "+
"higher than max allowed value of %v",
originTxSatoshi, btcutil.MaxSatoshi)
return 0, ruleError(ErrBadTxOutValue, str)
}
// The total of all outputs must not be more than the max
// allowed per transaction. Also, we could potentially overflow
// the accumulator so check for overflow.
lastSatoshiIn := totalSatoshiIn
totalSatoshiIn += originTxSatoshi
if totalSatoshiIn < lastSatoshiIn ||
totalSatoshiIn > btcutil.MaxSatoshi {
str := fmt.Sprintf("total value of all transaction "+
"inputs is %v which is higher than max "+
"allowed value of %v", totalSatoshiIn,
btcutil.MaxSatoshi)
return 0, ruleError(ErrBadTxOutValue, str)
}
// Mark the referenced output as spent.
originTx.Spent[originTxIndex] = true
}
// Calculate the total output amount for this transaction. It is safe
// to ignore overflow and out of range errors here because those error
// conditions would have already been caught by checkTransactionSanity.
var totalSatoshiOut int64
for _, txOut := range tx.MsgTx().TxOut {
totalSatoshiOut += txOut.Value
}
// Ensure the transaction does not spend more than its inputs.
if totalSatoshiIn < totalSatoshiOut {
str := fmt.Sprintf("total value of all transaction inputs for "+
"transaction %v is %v which is less than the amount "+
"spent of %v", txHash, totalSatoshiIn, totalSatoshiOut)
return 0, ruleError(ErrSpendTooHigh, str)
}
// NOTE: bitcoind checks if the transaction fees are < 0 here, but that
// is an impossible condition because of the check above that ensures
// the inputs are >= the outputs.
txFeeInSatoshi := totalSatoshiIn - totalSatoshiOut
return txFeeInSatoshi, nil
}
