// spendNestedWitnessPubKey generates both a sigScript, and valid witness for
// spending the passed pkScript with the specified input amount. The generated
// sigScript is the version 0 p2wkh witness program corresponding to the queried
// key. The witness stack is identical to that of one which spends a regular
// p2wkh output. The input amount *must* correspond to the output value of the
// previous pkScript, or else verification will fail since the new sighash
// digest algorithm defined in BIP0143 includes the input value in the sighash.
func spendNestedWitnessPubKeyHash(txIn *wire.TxIn, pkScript []byte,
inputValue int64, chainParams *chaincfg.Params, secrets SecretsSource,
tx *wire.MsgTx, hashCache *txscript.TxSigHashes, idx int) error {
// First we need to obtain the key pair related to this p2sh output.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(pkScript,
chainParams)
if err != nil {
return err
}
privKey, compressed, err := secrets.GetKey(addrs[0])
if err != nil {
return err
}
pubKey := privKey.PubKey()
var pubKeyHash []byte
if compressed {
pubKeyHash = btcutil.Hash160(pubKey.SerializeCompressed())
} else {
pubKeyHash = btcutil.Hash160(pubKey.SerializeUncompressed())
}
// Next, we'll generate a valid sigScript that'll allow us to spend
// the p2sh output. The sigScript will contain only a single push of
// the p2wkh witness program corresponding to the matching public key
// of this address.
p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(pubKeyHash, chainParams)
if err != nil {
return err
}
witnessProgram, err := txscript.PayToAddrScript(p2wkhAddr)
if err != nil {
return err
}
bldr := txscript.NewScriptBuilder()
bldr.AddData(witnessProgram)
sigScript, err := bldr.Script()
if err != nil {
return err
}
txIn.SignatureScript = sigScript
// With the sigScript in place, we'll next generate the proper witness
// that'll allow us to spend the p2wkh output.
witnessScript, err := txscript.WitnessScript(tx, hashCache, idx,
inputValue, witnessProgram, txscript.SigHashAll, privKey, compressed)
if err != nil {
return err
}
txIn.Witness = witnessScript
return nil
}
func lookupInputAccount(w *Wallet, details *wtxmgr.TxDetails, deb wtxmgr.DebitRecord) uint32 {
// TODO: Debits should record which account(s?) they
// debit from so this doesn't need to be looked up.
prevOP := &details.MsgTx.TxIn[deb.Index].PreviousOutPoint
prev, err := w.TxStore.TxDetails(&prevOP.Hash)
if err != nil {
log.Errorf("Cannot query previous transaction details for %v: %v", prevOP.Hash, err)
return 0
}
if prev == nil {
log.Errorf("Missing previous transaction %v", prevOP.Hash)
return 0
}
prevOut := prev.MsgTx.TxOut[prevOP.Index]
_, addrs, _, err := txscript.ExtractPkScriptAddrs(prevOut.PkScript, w.chainParams)
var inputAcct uint32
if err == nil && len(addrs) > 0 {
inputAcct, err = w.Manager.AddrAccount(addrs[0])
}
if err != nil {
log.Errorf("Cannot fetch account for previous output %v: %v", prevOP, err)
inputAcct = 0
}
return inputAcct
}
// indexUnconfirmedAddresses modifies the unconfirmed (memory-only) address
// index to include mappings for the addresses encoded by the passed public key
// script to the transaction.
//
// This function is safe for concurrent access.
func (idx *AddrIndex) indexUnconfirmedAddresses(pkScript []byte, tx *btcutil.Tx) {
// The error is ignored here since the only reason it can fail is if the
// script fails to parse and it was already validated before being
// admitted to the mempool.
_, addresses, _, _ := txscript.ExtractPkScriptAddrs(pkScript,
idx.chainParams)
for _, addr := range addresses {
// Ignore unsupported address types.
addrKey, err := addrToKey(addr)
if err != nil {
continue
}
// Add a mapping from the address to the transaction.
idx.unconfirmedLock.Lock()
addrIndexEntry := idx.txnsByAddr[addrKey]
if addrIndexEntry == nil {
addrIndexEntry = make(map[chainhash.Hash]*btcutil.Tx)
idx.txnsByAddr[addrKey] = addrIndexEntry
}
addrIndexEntry[*tx.Hash()] = tx
// Add a mapping from the transaction to the address.
addrsByTxEntry := idx.addrsByTx[*tx.Hash()]
if addrsByTxEntry == nil {
addrsByTxEntry = make(map[[addrKeySize]byte]struct{})
idx.addrsByTx[*tx.Hash()] = addrsByTxEntry
}
addrsByTxEntry[addrKey] = struct{}{}
idx.unconfirmedLock.Unlock()
}
}
// handleFundingResponse processes a response to the workflow initiation sent
// by the remote peer. This message then queues a message with the funding
// outpoint, and a commitment signature to the remote peer.
func (f *fundingManager) handleFundingResponse(fmsg *fundingResponseMsg) {
msg := fmsg.msg
sourcePeer := fmsg.peer
f.resMtx.RLock()
resCtx := f.activeReservations[fmsg.peer.id][msg.ChannelID]
f.resMtx.RUnlock()
fndgLog.Infof("Recv'd fundingResponse for pendingID(%v)", msg.ChannelID)
// The remote node has responded with their portion of the channel
// contribution. At this point, we can process their contribution which
// allows us to construct and sign both the commitment transaction, and
// the funding transaction.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(msg.DeliveryPkScript, activeNetParams.Params)
if err != nil {
fndgLog.Errorf("Unable to extract addresses from script: %v", err)
resCtx.err <- err
return
}
contribution := &lnwallet.ChannelContribution{
FundingAmount: 0,
MultiSigKey: msg.ChannelDerivationPoint,
CommitKey: msg.CommitmentKey,
DeliveryAddress: addrs[0],
RevocationKey: msg.RevocationKey,
CsvDelay: msg.CsvDelay,
}
if err := resCtx.reservation.ProcessContribution(contribution); err != nil {
fndgLog.Errorf("Unable to process contribution from %v: %v",
sourcePeer, err)
fmsg.peer.Disconnect()
resCtx.err <- err
return
}
// Now that we have their contribution, we can extract, then send over
// both the funding out point and our signature for their version of
// the commitment transaction to the remote peer.
outPoint := resCtx.reservation.FundingOutpoint()
_, sig := resCtx.reservation.OurSignatures()
commitSig, err := btcec.ParseSignature(sig, btcec.S256())
if err != nil {
fndgLog.Errorf("Unable to parse signature: %v", err)
resCtx.err <- err
return
}
// Register a new barrier for this channel to properly synchronize with
// the peer's readHandler once the channel is open.
fmsg.peer.barrierInits <- *outPoint
fndgLog.Infof("Generated ChannelPoint(%v) for pendingID(%v)",
outPoint, msg.ChannelID)
revocationKey := resCtx.reservation.OurContribution().RevocationKey
fundingComplete := lnwire.NewSingleFundingComplete(msg.ChannelID,
outPoint, commitSig, revocationKey)
sourcePeer.queueMsg(fundingComplete, nil)
}
// indexPkScript extracts all standard addresses from the passed public key
// script and maps each of them to the associated transaction using the passed
// map.
func (idx *AddrIndex) indexPkScript(data writeIndexData, pkScript []byte, txIdx int) {
// Nothing to index if the script is non-standard or otherwise doesn't
// contain any addresses.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(pkScript,
idx.chainParams)
if err != nil || len(addrs) == 0 {
return
}
for _, addr := range addrs {
addrKey, err := addrToKey(addr)
if err != nil {
// Ignore unsupported address types.
continue
}
// Avoid inserting the transaction more than once. Since the
// transactions are indexed serially any duplicates will be
// indexed in a row, so checking the most recent entry for the
// address is enough to detect duplicates.
indexedTxns := data[addrKey]
numTxns := len(indexedTxns)
if numTxns > 0 && indexedTxns[numTxns-1] == txIdx {
continue
}
indexedTxns = append(indexedTxns, txIdx)
data[addrKey] = indexedTxns
}
}
// This example demonstrates extracting information from a standard public key
// script.
func ExampleExtractPkScriptAddrs() {
// Start with a standard pay-to-pubkey-hash script.
scriptHex := "76a914128004ff2fcaf13b2b91eb654b1dc2b674f7ec6188ac"
script, err := hex.DecodeString(scriptHex)
if err != nil {
fmt.Println(err)
return
}
// Extract and print details from the script.
scriptClass, addresses, reqSigs, err := txscript.ExtractPkScriptAddrs(
script, &chaincfg.MainNetParams)
if err != nil {
fmt.Println(err)
return
}
fmt.Println("Script Class:", scriptClass)
fmt.Println("Addresses:", addresses)
fmt.Println("Required Signatures:", reqSigs)
// Output:
// Script Class: pubkeyhash
// Addresses: [12gpXQVcCL2qhTNQgyLVdCFG2Qs2px98nV]
// Required Signatures: 1
}
// signMultiSigUTXO signs the P2SH UTXO with the given index by constructing a
// script containing all given signatures plus the redeem (multi-sig) script. The
// redeem script is obtained by looking up the address of the given P2SH pkScript
// on the address manager.
// The order of the signatures must match that of the public keys in the multi-sig
// script as OP_CHECKMULTISIG expects that.
// This function must be called with the manager unlocked.
func signMultiSigUTXO(mgr *waddrmgr.Manager, tx *wire.MsgTx, idx int, pkScript []byte, sigs []RawSig) error {
class, addresses, _, err := txscript.ExtractPkScriptAddrs(pkScript, mgr.ChainParams())
if err != nil {
return newError(ErrTxSigning, "unparseable pkScript", err)
}
if class != txscript.ScriptHashTy {
return newError(ErrTxSigning, fmt.Sprintf("pkScript is not P2SH: %s", class), nil)
}
redeemScript, err := getRedeemScript(mgr, addresses[0].(*btcutil.AddressScriptHash))
if err != nil {
return newError(ErrTxSigning, "unable to retrieve redeem script", err)
}
class, _, nRequired, err := txscript.ExtractPkScriptAddrs(redeemScript, mgr.ChainParams())
if err != nil {
return newError(ErrTxSigning, "unparseable redeem script", err)
}
if class != txscript.MultiSigTy {
return newError(ErrTxSigning, fmt.Sprintf("redeem script is not multi-sig: %v", class), nil)
}
if len(sigs) < nRequired {
errStr := fmt.Sprintf("not enough signatures; need %d but got only %d", nRequired,
len(sigs))
return newError(ErrTxSigning, errStr, nil)
}
// Construct the unlocking script.
// Start with an OP_0 because of the bug in bitcoind, then add nRequired signatures.
unlockingScript := txscript.NewScriptBuilder().AddOp(txscript.OP_FALSE)
for _, sig := range sigs[:nRequired] {
unlockingScript.AddData(sig)
}
// Combine the redeem script and the unlocking script to get the actual signature script.
sigScript := unlockingScript.AddData(redeemScript)
script, err := sigScript.Script()
if err != nil {
return newError(ErrTxSigning, "error building sigscript", err)
}
tx.TxIn[idx].SignatureScript = script
if err := validateSigScript(tx, idx, pkScript); err != nil {
return err
}
return nil
}
func (w *Wallet) findEligibleOutputs(account uint32, minconf int32, bs *waddrmgr.BlockStamp) ([]wtxmgr.Credit, error) {
unspent, err := w.TxStore.UnspentOutputs()
if err != nil {
return nil, err
}
// TODO: Eventually all of these filters (except perhaps output locking)
// should be handled by the call to UnspentOutputs (or similar).
// Because one of these filters requires matching the output script to
// the desired account, this change depends on making wtxmgr a waddrmgr
// dependancy and requesting unspent outputs for a single account.
eligible := make([]wtxmgr.Credit, 0, len(unspent))
for i := range unspent {
output := &unspent[i]
// Only include this output if it meets the required number of
// confirmations. Coinbase transactions must have have reached
// maturity before their outputs may be spent.
if !confirmed(minconf, output.Height, bs.Height) {
continue
}
if output.FromCoinBase {
const target = blockchain.CoinbaseMaturity
if !confirmed(target, output.Height, bs.Height) {
continue
}
}
// Locked unspent outputs are skipped.
if w.LockedOutpoint(output.OutPoint) {
continue
}
// Only include the output if it is associated with the passed
// account.
//
// TODO: Handle multisig outputs by determining if enough of the
// addresses are controlled.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(
output.PkScript, w.chainParams)
if err != nil || len(addrs) != 1 {
continue
}
addrAcct, err := w.Manager.AddrAccount(addrs[0])
if err != nil || addrAcct != account {
continue
}
eligible = append(eligible, *output)
}
return eligible, nil
}
func lookupOutputChain(w *Wallet, details *wtxmgr.TxDetails, cred wtxmgr.CreditRecord) (account uint32, internal bool) {
output := details.MsgTx.TxOut[cred.Index]
_, addrs, _, err := txscript.ExtractPkScriptAddrs(output.PkScript, w.chainParams)
var ma waddrmgr.ManagedAddress
if err == nil && len(addrs) > 0 {
ma, err = w.Manager.Address(addrs[0])
}
if err != nil {
log.Errorf("Cannot fetch account for wallet output: %v", err)
} else {
account = ma.Account()
internal = ma.Internal()
}
return
}
// spendWitnessKeyHash generates, and sets a valid witness for spending the
// passed pkScript with the specified input amount. The input amount *must*
// correspond to the output value of the previous pkScript, or else verification
// will fail since the new sighash digest algorithm defined in BIP0143 includes
// the input value in the sighash.
func spendWitnessKeyHash(txIn *wire.TxIn, pkScript []byte,
inputValue int64, chainParams *chaincfg.Params, secrets SecretsSource,
tx *wire.MsgTx, hashCache *txscript.TxSigHashes, idx int) error {
// First obtain the key pair associated with this p2wkh address.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(pkScript,
chainParams)
if err != nil {
return err
}
privKey, compressed, err := secrets.GetKey(addrs[0])
if err != nil {
return err
}
pubKey := privKey.PubKey()
// Once we have the key pair, generate a p2wkh address type, respecting
// the compression type of the generated key.
var pubKeyHash []byte
if compressed {
pubKeyHash = btcutil.Hash160(pubKey.SerializeCompressed())
} else {
pubKeyHash = btcutil.Hash160(pubKey.SerializeUncompressed())
}
p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(pubKeyHash, chainParams)
if err != nil {
return err
}
// With the concrete address type, we can now generate the
// corresponding witness program to be used to generate a valid witness
// which will allow us to spend this output.
witnessProgram, err := txscript.PayToAddrScript(p2wkhAddr)
if err != nil {
return err
}
witnessScript, err := txscript.WitnessScript(tx, hashCache, idx,
inputValue, witnessProgram, txscript.SigHashAll, privKey, true)
if err != nil {
return err
}
txIn.Witness = witnessScript
return nil
}
// fetchOutputKey attempts to fetch the managed address corresponding to the
// passed output script. This function is used to look up the proper key which
// should be used to sign a specified input.
func (b *BtcWallet) fetchOutputAddr(script []byte) (waddrmgr.ManagedAddress, error) {
_, addrs, _, err := txscript.ExtractPkScriptAddrs(script, b.netParams)
if err != nil {
return nil, err
}
// If the case of a multi-sig output, several address may be extracted.
// Therefore, we simply select the key for the first address we know
// of.
for _, addr := range addrs {
wAddr, err := b.wallet.Manager.Address(addr)
if err == nil {
return wAddr, nil
}
}
// TODO(roasbeef): use the errors.wrap package
return nil, fmt.Errorf("address not found")
}
func totalBalances(w *Wallet, m map[uint32]btcutil.Amount) error {
unspent, err := w.TxStore.UnspentOutputs()
if err != nil {
return err
}
for i := range unspent {
output := &unspent[i]
var outputAcct uint32
_, addrs, _, err := txscript.ExtractPkScriptAddrs(
output.PkScript, w.chainParams)
if err == nil && len(addrs) > 0 {
outputAcct, err = w.Manager.AddrAccount(addrs[0])
}
if err == nil {
_, ok := m[outputAcct]
if ok {
m[outputAcct] += output.Amount
}
}
}
return nil
}
// groupCreditsByAddr converts a slice of credits to a map from the string
// representation of an encoded address to the unspent outputs associated with
// that address.
func groupCreditsByAddr(credits []wtxmgr.Credit, chainParams *chaincfg.Params) (
map[string][]wtxmgr.Credit, error) {
addrMap := make(map[string][]wtxmgr.Credit)
for _, c := range credits {
_, addrs, _, err := txscript.ExtractPkScriptAddrs(c.PkScript, chainParams)
if err != nil {
return nil, newError(ErrInputSelection, "failed to obtain input address", err)
}
// As our credits are all P2SH we should never have more than one
// address per credit, so let's error out if that assumption is
// violated.
if len(addrs) != 1 {
return nil, newError(ErrInputSelection, "input doesn't have exactly one address", nil)
}
encAddr := addrs[0].EncodeAddress()
if v, ok := addrMap[encAddr]; ok {
addrMap[encAddr] = append(v, c)
} else {
addrMap[encAddr] = []wtxmgr.Credit{c}
}
}
return addrMap, nil
}
// handleSingleFundingRequest creates an initial 'ChannelReservation' within
// the wallet, then responds to the source peer with a single funder response
// message progressing the funding workflow.
// TODO(roasbeef): add error chan to all, let channelManager handle
// error+propagate
func (f *fundingManager) handleFundingRequest(fmsg *fundingRequestMsg) {
// Check number of pending channels to be smaller than maximum allowed
// number and send ErrorGeneric to remote peer if condition is violated.
if len(f.activeReservations[fmsg.peer.id]) >= cfg.MaxPendingChannels {
errMsg := &lnwire.ErrorGeneric{
ChannelPoint: &wire.OutPoint{
Hash: wire.ShaHash{},
Index: 0,
},
Problem: "Number of pending channels exceed maximum",
Code: lnwire.ErrorMaxPendingChannels,
PendingChannelID: fmsg.msg.ChannelID,
}
fmsg.peer.queueMsg(errMsg, nil)
return
}
msg := fmsg.msg
amt := msg.FundingAmount
delay := msg.CsvDelay
// TODO(roasbeef): error if funding flow already ongoing
fndgLog.Infof("Recv'd fundingRequest(amt=%v, delay=%v, pendingId=%v) "+
"from peerID(%v)", amt, delay, msg.ChannelID, fmsg.peer.id)
// Attempt to initialize a reservation within the wallet. If the wallet
// has insufficient resources to create the channel, then the reservation
// attempt may be rejected. Note that since we're on the responding
// side of a single funder workflow, we don't commit any funds to the
// channel ourselves.
// TODO(roasbeef): passing num confs 1 is irrelevant here, make signed?
reservation, err := f.wallet.InitChannelReservation(amt, 0,
fmsg.peer.addr.IdentityKey, fmsg.peer.addr.Address, 1, delay)
if err != nil {
// TODO(roasbeef): push ErrorGeneric message
fndgLog.Errorf("Unable to initialize reservation: %v", err)
fmsg.peer.Disconnect()
return
}
// Once the reservation has been created successfully, we add it to this
// peers map of pending reservations to track this particular reservation
// until either abort or completion.
f.resMtx.Lock()
if _, ok := f.activeReservations[fmsg.peer.id]; !ok {
f.activeReservations[fmsg.peer.id] = make(pendingChannels)
}
f.activeReservations[fmsg.peer.id][msg.ChannelID] = &reservationWithCtx{
reservation: reservation,
peer: fmsg.peer,
}
f.resMtx.Unlock()
// With our portion of the reservation initialied, process the
// initiators contribution to the channel.
_, addrs, _, err := txscript.ExtractPkScriptAddrs(msg.DeliveryPkScript, activeNetParams.Params)
if err != nil {
fndgLog.Errorf("Unable to extract addresses from script: %v", err)
return
}
contribution := &lnwallet.ChannelContribution{
FundingAmount: amt,
MultiSigKey: msg.ChannelDerivationPoint,
CommitKey: msg.CommitmentKey,
DeliveryAddress: addrs[0],
CsvDelay: delay,
}
if err := reservation.ProcessSingleContribution(contribution); err != nil {
fndgLog.Errorf("unable to add contribution reservation: %v", err)
fmsg.peer.Disconnect()
return
}
fndgLog.Infof("Sending fundingResp for pendingID(%v)", msg.ChannelID)
// With the initiator's contribution recorded, response with our
// contribution in the next message of the workflow.
ourContribution := reservation.OurContribution()
deliveryScript, err := txscript.PayToAddrScript(ourContribution.DeliveryAddress)
if err != nil {
fndgLog.Errorf("unable to convert address to pkscript: %v", err)
return
}
fundingResp := lnwire.NewSingleFundingResponse(msg.ChannelID,
ourContribution.RevocationKey, ourContribution.CommitKey,
ourContribution.MultiSigKey, ourContribution.CsvDelay,
deliveryScript)
fmsg.peer.queueMsg(fundingResp, nil)
}
func (w *Wallet) addRelevantTx(rec *wtxmgr.TxRecord, block *wtxmgr.BlockMeta) error {
// TODO: The transaction store and address manager need to be updated
// together, but each operate under different namespaces and are changed
// under new transactions. This is not error safe as we lose
// transaction semantics.
//
// I'm unsure of the best way to solve this. Some possible solutions
// and drawbacks:
//
// 1. Open write transactions here and pass the handle to every
// waddrmr and wtxmgr method. This complicates the caller code
// everywhere, however.
//
// 2. Move the wtxmgr namespace into the waddrmgr namespace, likely
// under its own bucket. This entire function can then be moved
// into the waddrmgr package, which updates the nested wtxmgr.
// This removes some of separation between the components.
//
// 3. Use multiple wtxmgrs, one for each account, nested in the
// waddrmgr namespace. This still provides some sort of logical
// separation (transaction handling remains in another package, and
// is simply used by waddrmgr), but may result in duplicate
// transactions being saved if they are relevant to multiple
// accounts.
//
// 4. Store wtxmgr-related details under the waddrmgr namespace, but
// solve the drawback of #3 by splitting wtxmgr to save entire
// transaction records globally for all accounts, with
// credit/debit/balance tracking per account. Each account would
// also save the relevant transaction hashes and block incidence so
// the full transaction can be loaded from the waddrmgr
// transactions bucket. This currently seems like the best
// solution.
// At the moment all notified transactions are assumed to actually be
// relevant. This assumption will not hold true when SPV support is
// added, but until then, simply insert the transaction because there
// should either be one or more relevant inputs or outputs.
err := w.TxStore.InsertTx(rec, block)
if err != nil {
return err
}
// Check every output to determine whether it is controlled by a wallet
// key. If so, mark the output as a credit.
for i, output := range rec.MsgTx.TxOut {
_, addrs, _, err := txscript.ExtractPkScriptAddrs(output.PkScript,
w.chainParams)
if err != nil {
// Non-standard outputs are skipped.
continue
}
for _, addr := range addrs {
ma, err := w.Manager.Address(addr)
if err == nil {
// TODO: Credits should be added with the
// account they belong to, so wtxmgr is able to
// track per-account balances.
err = w.TxStore.AddCredit(rec, block, uint32(i),
ma.Internal())
if err != nil {
return err
}
err = w.Manager.MarkUsed(addr)
if err != nil {
return err
}
log.Debugf("Marked address %v used", addr)
continue
}
// Missing addresses are skipped. Other errors should
// be propagated.
if !waddrmgr.IsError(err, waddrmgr.ErrAddressNotFound) {
return err
}
}
}
// Send notification of mined or unmined transaction to any interested
// clients.
//
// TODO: Avoid the extra db hits.
if block == nil {
details, err := w.TxStore.UniqueTxDetails(&rec.Hash, nil)
if err != nil {
log.Errorf("Cannot query transaction details for notifiation: %v", err)
} else {
w.NtfnServer.notifyUnminedTransaction(details)
}
} else {
details, err := w.TxStore.UniqueTxDetails(&rec.Hash, &block.Block)
if err != nil {
log.Errorf("Cannot query transaction details for notifiation: %v", err)
} else {
w.NtfnServer.notifyMinedTransaction(details, block)
}
}
return nil
}
func (s *walletServer) FundTransaction(ctx context.Context, req *pb.FundTransactionRequest) (
*pb.FundTransactionResponse, error) {
// TODO: A predicate function for selecting outputs should be created
// and passed to a database view of just a particular account's utxos to
// prevent reading every unspent transaction output from every account
// into memory at once.
syncBlock := s.wallet.Manager.SyncedTo()
outputs, err := s.wallet.TxStore.UnspentOutputs()
if err != nil {
return nil, translateError(err)
}
selectedOutputs := make([]*pb.FundTransactionResponse_PreviousOutput, 0, len(outputs))
var totalAmount btcutil.Amount
for i := range outputs {
output := &outputs[i]
if !confirmed(req.RequiredConfirmations, output.Height, syncBlock.Height) {
continue
}
if !req.IncludeImmatureCoinbases && output.FromCoinBase &&
!confirmed(blockchain.CoinbaseMaturity, output.Height, syncBlock.Height) {
continue
}
_, addrs, _, err := txscript.ExtractPkScriptAddrs(
output.PkScript, s.wallet.ChainParams())
if err != nil || len(addrs) == 0 {
// Cannot determine which account this belongs to
// without a valid address. Fix this by saving
// outputs per account (per-account wtxmgr).
continue
}
outputAcct, err := s.wallet.Manager.AddrAccount(addrs[0])
if err != nil {
return nil, translateError(err)
}
if outputAcct != req.Account {
continue
}
selectedOutputs = append(selectedOutputs, &pb.FundTransactionResponse_PreviousOutput{
TransactionHash: output.OutPoint.Hash[:],
OutputIndex: output.Index,
Amount: int64(output.Amount),
PkScript: output.PkScript,
ReceiveTime: output.Received.Unix(),
FromCoinbase: output.FromCoinBase,
})
totalAmount += output.Amount
if req.TargetAmount != 0 && totalAmount > btcutil.Amount(req.TargetAmount) {
break
}
}
var changeScript []byte
if req.IncludeChangeScript && totalAmount > btcutil.Amount(req.TargetAmount) {
changeAddr, err := s.wallet.NewChangeAddress(req.Account, waddrmgr.PubKeyHash)
if err != nil {
return nil, translateError(err)
}
changeScript, err = txscript.PayToAddrScript(changeAddr)
if err != nil {
return nil, translateError(err)
}
}
return &pb.FundTransactionResponse{
SelectedOutputs: selectedOutputs,
TotalAmount: int64(totalAmount),
ChangePkScript: changeScript,
}, nil
}