lnd.xprv/lnwallet/btcwallet/btcwallet.go

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package btcwallet
import (
"bytes"
"encoding/hex"
"fmt"
"math"
"sync"
"time"
"github.com/btcsuite/btcd/chaincfg"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwallet/chain"
"github.com/btcsuite/btcwallet/waddrmgr"
base "github.com/btcsuite/btcwallet/wallet"
"github.com/btcsuite/btcwallet/wallet/txauthor"
"github.com/btcsuite/btcwallet/wallet/txrules"
"github.com/btcsuite/btcwallet/walletdb"
"github.com/lightningnetwork/lnd/keychain"
"github.com/lightningnetwork/lnd/lnwallet"
)
const (
defaultAccount = uint32(waddrmgr.DefaultAccountNum)
)
var (
// waddrmgrNamespaceKey is the namespace key that the waddrmgr state is
// stored within the top-level waleltdb buckets of btcwallet.
waddrmgrNamespaceKey = []byte("waddrmgr")
// lightningAddrSchema is the scope addr schema for all keys that we
// derive. We'll treat them all as p2wkh addresses, as atm we must
// specify a particular type.
lightningAddrSchema = waddrmgr.ScopeAddrSchema{
ExternalAddrType: waddrmgr.WitnessPubKey,
InternalAddrType: waddrmgr.WitnessPubKey,
}
)
// BtcWallet is an implementation of the lnwallet.WalletController interface
// backed by an active instance of btcwallet. At the time of the writing of
// this documentation, this implementation requires a full btcd node to
// operate.
type BtcWallet struct {
// wallet is an active instance of btcwallet.
wallet *base.Wallet
chain chain.Interface
db walletdb.DB
cfg *Config
netParams *chaincfg.Params
chainKeyScope waddrmgr.KeyScope
}
// A compile time check to ensure that BtcWallet implements the
// WalletController and BlockChainIO interfaces.
var _ lnwallet.WalletController = (*BtcWallet)(nil)
var _ lnwallet.BlockChainIO = (*BtcWallet)(nil)
// New returns a new fully initialized instance of BtcWallet given a valid
// configuration struct.
func New(cfg Config) (*BtcWallet, error) {
// Ensure the wallet exists or create it when the create flag is set.
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netDir := NetworkDir(cfg.DataDir, cfg.NetParams)
// Create the key scope for the coin type being managed by this wallet.
chainKeyScope := waddrmgr.KeyScope{
Purpose: keychain.BIP0043Purpose,
Coin: cfg.CoinType,
}
// Maybe the wallet has already been opened and unlocked by the
// WalletUnlocker. So if we get a non-nil value from the config,
// we assume everything is in order.
var wallet = cfg.Wallet
if wallet == nil {
// No ready wallet was passed, so try to open an existing one.
var pubPass []byte
if cfg.PublicPass == nil {
pubPass = defaultPubPassphrase
} else {
pubPass = cfg.PublicPass
}
loader := base.NewLoader(
cfg.NetParams, netDir, cfg.NoFreelistSync,
cfg.RecoveryWindow,
)
walletExists, err := loader.WalletExists()
if err != nil {
return nil, err
}
if !walletExists {
// Wallet has never been created, perform initial
// set up.
wallet, err = loader.CreateNewWallet(
pubPass, cfg.PrivatePass, cfg.HdSeed,
cfg.Birthday,
)
if err != nil {
return nil, err
}
} else {
// Wallet has been created and been initialized at
// this point, open it along with all the required DB
// namespaces, and the DB itself.
wallet, err = loader.OpenExistingWallet(pubPass, false)
if err != nil {
return nil, err
}
}
}
return &BtcWallet{
cfg: &cfg,
wallet: wallet,
db: wallet.Database(),
chain: cfg.ChainSource,
netParams: cfg.NetParams,
chainKeyScope: chainKeyScope,
}, nil
}
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// BackEnd returns the underlying ChainService's name as a string.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) BackEnd() string {
if b.chain != nil {
return b.chain.BackEnd()
}
return ""
}
// InternalWallet returns a pointer to the internal base wallet which is the
// core of btcwallet.
func (b *BtcWallet) InternalWallet() *base.Wallet {
return b.wallet
}
// Start initializes the underlying rpc connection, the wallet itself, and
// begins syncing to the current available blockchain state.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) Start() error {
// We'll start by unlocking the wallet and ensuring that the KeyScope:
// (1017, 1) exists within the internal waddrmgr. We'll need this in
// order to properly generate the keys required for signing various
// contracts.
if err := b.wallet.Unlock(b.cfg.PrivatePass, nil); err != nil {
return err
}
_, err := b.wallet.Manager.FetchScopedKeyManager(b.chainKeyScope)
if err != nil {
// If the scope hasn't yet been created (it wouldn't been
// loaded by default if it was), then we'll manually create the
// scope for the first time ourselves.
err := walletdb.Update(b.db, func(tx walletdb.ReadWriteTx) error {
addrmgrNs := tx.ReadWriteBucket(waddrmgrNamespaceKey)
_, err := b.wallet.Manager.NewScopedKeyManager(
addrmgrNs, b.chainKeyScope, lightningAddrSchema,
)
return err
})
if err != nil {
return err
}
}
// Establish an RPC connection in addition to starting the goroutines
// in the underlying wallet.
if err := b.chain.Start(); err != nil {
return err
}
// Start the underlying btcwallet core.
b.wallet.Start()
// Pass the rpc client into the wallet so it can sync up to the
// current main chain.
b.wallet.SynchronizeRPC(b.chain)
return nil
}
// Stop signals the wallet for shutdown. Shutdown may entail closing
// any active sockets, database handles, stopping goroutines, etc.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) Stop() error {
b.wallet.Stop()
b.wallet.WaitForShutdown()
b.chain.Stop()
return nil
}
// ConfirmedBalance returns the sum of all the wallet's unspent outputs that
// have at least confs confirmations. If confs is set to zero, then all unspent
// outputs, including those currently in the mempool will be included in the
// final sum.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) ConfirmedBalance(confs int32) (btcutil.Amount, error) {
var balance btcutil.Amount
witnessOutputs, err := b.ListUnspentWitness(confs, math.MaxInt32)
if err != nil {
return 0, err
}
for _, witnessOutput := range witnessOutputs {
balance += witnessOutput.Value
}
return balance, nil
}
// NewAddress returns the next external or internal address for the wallet
// dictated by the value of the `change` parameter. If change is true, then an
// internal address will be returned, otherwise an external address should be
// returned.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) NewAddress(t lnwallet.AddressType, change bool) (btcutil.Address, error) {
var keyScope waddrmgr.KeyScope
switch t {
case lnwallet.WitnessPubKey:
keyScope = waddrmgr.KeyScopeBIP0084
case lnwallet.NestedWitnessPubKey:
keyScope = waddrmgr.KeyScopeBIP0049Plus
default:
return nil, fmt.Errorf("unknown address type")
}
if change {
return b.wallet.NewChangeAddress(defaultAccount, keyScope)
}
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return b.wallet.NewAddress(defaultAccount, keyScope)
}
// LastUnusedAddress returns the last *unused* address known by the wallet. An
// address is unused if it hasn't received any payments. This can be useful in
// UIs in order to continually show the "freshest" address without having to
// worry about "address inflation" caused by continual refreshing. Similar to
// NewAddress it can derive a specified address type, and also optionally a
// change address.
func (b *BtcWallet) LastUnusedAddress(addrType lnwallet.AddressType) (
btcutil.Address, error) {
var keyScope waddrmgr.KeyScope
switch addrType {
case lnwallet.WitnessPubKey:
keyScope = waddrmgr.KeyScopeBIP0084
case lnwallet.NestedWitnessPubKey:
keyScope = waddrmgr.KeyScopeBIP0049Plus
default:
return nil, fmt.Errorf("unknown address type")
}
return b.wallet.CurrentAddress(defaultAccount, keyScope)
}
// IsOurAddress checks if the passed address belongs to this wallet
//
// This is a part of the WalletController interface.
func (b *BtcWallet) IsOurAddress(a btcutil.Address) bool {
result, err := b.wallet.HaveAddress(a)
return result && (err == nil)
}
// SendOutputs funds, signs, and broadcasts a Bitcoin transaction paying out to
// the specified outputs. In the case the wallet has insufficient funds, or the
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// outputs are non-standard, a non-nil error will be returned.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) SendOutputs(outputs []*wire.TxOut,
feeRate lnwallet.SatPerKWeight) (*wire.MsgTx, error) {
// Convert our fee rate from sat/kw to sat/kb since it's required by
// SendOutputs.
feeSatPerKB := btcutil.Amount(feeRate.FeePerKVByte())
// Sanity check outputs.
if len(outputs) < 1 {
return nil, lnwallet.ErrNoOutputs
}
return b.wallet.SendOutputs(outputs, defaultAccount, 1, feeSatPerKB)
}
// CreateSimpleTx creates a Bitcoin transaction paying to the specified
// outputs. The transaction is not broadcasted to the network, but a new change
// address might be created in the wallet database. In the case the wallet has
// insufficient funds, or the outputs are non-standard, an error should be
// returned. This method also takes the target fee expressed in sat/kw that
// should be used when crafting the transaction.
//
// NOTE: The dryRun argument can be set true to create a tx that doesn't alter
// the database. A tx created with this set to true SHOULD NOT be broadcasted.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) CreateSimpleTx(outputs []*wire.TxOut,
feeRate lnwallet.SatPerKWeight, dryRun bool) (*txauthor.AuthoredTx, error) {
// The fee rate is passed in using units of sat/kw, so we'll convert
// this to sat/KB as the CreateSimpleTx method requires this unit.
feeSatPerKB := btcutil.Amount(feeRate.FeePerKVByte())
// Sanity check outputs.
if len(outputs) < 1 {
return nil, lnwallet.ErrNoOutputs
}
for _, output := range outputs {
// When checking an output for things like dusty-ness, we'll
// use the default mempool relay fee rather than the target
// effective fee rate to ensure accuracy. Otherwise, we may
// mistakenly mark small-ish, but not quite dust output as
// dust.
err := txrules.CheckOutput(
output, txrules.DefaultRelayFeePerKb,
)
if err != nil {
return nil, err
}
}
return b.wallet.CreateSimpleTx(defaultAccount, outputs, 1, feeSatPerKB, dryRun)
}
// LockOutpoint marks an outpoint as locked meaning it will no longer be deemed
// as eligible for coin selection. Locking outputs are utilized in order to
// avoid race conditions when selecting inputs for usage when funding a
// channel.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) LockOutpoint(o wire.OutPoint) {
b.wallet.LockOutpoint(o)
}
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// UnlockOutpoint unlocks a previously locked output, marking it eligible for
// coin selection.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) UnlockOutpoint(o wire.OutPoint) {
b.wallet.UnlockOutpoint(o)
}
// ListUnspentWitness returns a slice of all the unspent outputs the wallet
// controls which pay to witness programs either directly or indirectly.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) ListUnspentWitness(minConfs, maxConfs int32) (
[]*lnwallet.Utxo, error) {
// First, grab all the unfiltered currently unspent outputs.
unspentOutputs, err := b.wallet.ListUnspent(minConfs, maxConfs, nil)
if err != nil {
return nil, err
}
// Next, we'll run through all the regular outputs, only saving those
// which are p2wkh outputs or a p2wsh output nested within a p2sh output.
witnessOutputs := make([]*lnwallet.Utxo, 0, len(unspentOutputs))
for _, output := range unspentOutputs {
pkScript, err := hex.DecodeString(output.ScriptPubKey)
if err != nil {
return nil, err
}
addressType := lnwallet.UnknownAddressType
if txscript.IsPayToWitnessPubKeyHash(pkScript) {
addressType = lnwallet.WitnessPubKey
} else if txscript.IsPayToScriptHash(pkScript) {
// TODO(roasbeef): This assumes all p2sh outputs returned by the
// wallet are nested p2pkh. We can't check the redeem script because
// the btcwallet service does not include it.
addressType = lnwallet.NestedWitnessPubKey
}
if addressType == lnwallet.WitnessPubKey ||
addressType == lnwallet.NestedWitnessPubKey {
txid, err := chainhash.NewHashFromStr(output.TxID)
if err != nil {
return nil, err
}
// We'll ensure we properly convert the amount given in
// BTC to satoshis.
amt, err := btcutil.NewAmount(output.Amount)
if err != nil {
return nil, err
}
utxo := &lnwallet.Utxo{
AddressType: addressType,
Value: amt,
PkScript: pkScript,
OutPoint: wire.OutPoint{
Hash: *txid,
Index: output.Vout,
},
Confirmations: output.Confirmations,
}
witnessOutputs = append(witnessOutputs, utxo)
}
}
return witnessOutputs, nil
}
// PublishTransaction performs cursory validation (dust checks, etc), then
// finally broadcasts the passed transaction to the Bitcoin network. If
// publishing the transaction fails, an error describing the reason is returned
// (currently ErrDoubleSpend). If the transaction is already published to the
// network (either in the mempool or chain) no error will be returned.
func (b *BtcWallet) PublishTransaction(tx *wire.MsgTx) error {
if err := b.wallet.PublishTransaction(tx); err != nil {
// If we failed to publish the transaction, check whether we
// got an error of known type.
switch err.(type) {
// If the wallet reports a double spend, convert it to our
// internal ErrDoubleSpend and return.
case *base.ErrDoubleSpend:
return lnwallet.ErrDoubleSpend
// If the wallet reports a replacement error, return
// ErrDoubleSpend, as we currently are never attempting to
// replace transactions.
case *base.ErrReplacement:
return lnwallet.ErrDoubleSpend
default:
return err
}
}
return nil
}
// extractBalanceDelta extracts the net balance delta from the PoV of the
// wallet given a TransactionSummary.
func extractBalanceDelta(
txSummary base.TransactionSummary,
tx *wire.MsgTx,
) (btcutil.Amount, error) {
// For each input we debit the wallet's outflow for this transaction,
// and for each output we credit the wallet's inflow for this
// transaction.
var balanceDelta btcutil.Amount
for _, input := range txSummary.MyInputs {
balanceDelta -= input.PreviousAmount
}
for _, output := range txSummary.MyOutputs {
balanceDelta += btcutil.Amount(tx.TxOut[output.Index].Value)
}
return balanceDelta, nil
}
// minedTransactionsToDetails is a helper function which converts a summary
// information about mined transactions to a TransactionDetail.
func minedTransactionsToDetails(
currentHeight int32,
block base.Block,
chainParams *chaincfg.Params,
) ([]*lnwallet.TransactionDetail, error) {
details := make([]*lnwallet.TransactionDetail, 0, len(block.Transactions))
for _, tx := range block.Transactions {
wireTx := &wire.MsgTx{}
txReader := bytes.NewReader(tx.Transaction)
if err := wireTx.Deserialize(txReader); err != nil {
return nil, err
}
var destAddresses []btcutil.Address
for _, txOut := range wireTx.TxOut {
_, outAddresses, _, err := txscript.ExtractPkScriptAddrs(
txOut.PkScript, chainParams,
)
if err != nil {
return nil, err
}
destAddresses = append(destAddresses, outAddresses...)
}
txDetail := &lnwallet.TransactionDetail{
Hash: *tx.Hash,
NumConfirmations: currentHeight - block.Height + 1,
BlockHash: block.Hash,
BlockHeight: block.Height,
Timestamp: block.Timestamp,
TotalFees: int64(tx.Fee),
DestAddresses: destAddresses,
RawTx: tx.Transaction,
}
balanceDelta, err := extractBalanceDelta(tx, wireTx)
if err != nil {
return nil, err
}
txDetail.Value = balanceDelta
details = append(details, txDetail)
}
return details, nil
}
// unminedTransactionsToDetail is a helper function which converts a summary
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// for an unconfirmed transaction to a transaction detail.
func unminedTransactionsToDetail(
summary base.TransactionSummary,
chainParams *chaincfg.Params,
) (*lnwallet.TransactionDetail, error) {
wireTx := &wire.MsgTx{}
txReader := bytes.NewReader(summary.Transaction)
if err := wireTx.Deserialize(txReader); err != nil {
return nil, err
}
var destAddresses []btcutil.Address
for _, txOut := range wireTx.TxOut {
_, outAddresses, _, err :=
txscript.ExtractPkScriptAddrs(txOut.PkScript, chainParams)
if err != nil {
return nil, err
}
destAddresses = append(destAddresses, outAddresses...)
}
txDetail := &lnwallet.TransactionDetail{
Hash: *summary.Hash,
TotalFees: int64(summary.Fee),
Timestamp: summary.Timestamp,
DestAddresses: destAddresses,
RawTx: summary.Transaction,
}
balanceDelta, err := extractBalanceDelta(summary, wireTx)
if err != nil {
return nil, err
}
txDetail.Value = balanceDelta
return txDetail, nil
}
// ListTransactionDetails returns a list of all transactions which are
// relevant to the wallet.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) ListTransactionDetails() ([]*lnwallet.TransactionDetail, error) {
// Grab the best block the wallet knows of, we'll use this to calculate
// # of confirmations shortly below.
bestBlock := b.wallet.Manager.SyncedTo()
currentHeight := bestBlock.Height
// We'll attempt to find all unconfirmed transactions (height of -1),
// as well as all transactions that are known to have confirmed at this
// height.
start := base.NewBlockIdentifierFromHeight(0)
stop := base.NewBlockIdentifierFromHeight(-1)
txns, err := b.wallet.GetTransactions(start, stop, nil)
if err != nil {
return nil, err
}
txDetails := make([]*lnwallet.TransactionDetail, 0,
len(txns.MinedTransactions)+len(txns.UnminedTransactions))
// For both confirmed and unconfirmed transactions, create a
// TransactionDetail which re-packages the data returned by the base
// wallet.
for _, blockPackage := range txns.MinedTransactions {
details, err := minedTransactionsToDetails(
currentHeight, blockPackage, b.netParams,
)
if err != nil {
return nil, err
}
txDetails = append(txDetails, details...)
}
for _, tx := range txns.UnminedTransactions {
detail, err := unminedTransactionsToDetail(tx, b.netParams)
if err != nil {
return nil, err
}
txDetails = append(txDetails, detail)
}
return txDetails, nil
}
// txSubscriptionClient encapsulates the transaction notification client from
// the base wallet. Notifications received from the client will be proxied over
// two distinct channels.
type txSubscriptionClient struct {
txClient base.TransactionNotificationsClient
confirmed chan *lnwallet.TransactionDetail
unconfirmed chan *lnwallet.TransactionDetail
w *base.Wallet
wg sync.WaitGroup
quit chan struct{}
}
// ConfirmedTransactions returns a channel which will be sent on as new
// relevant transactions are confirmed.
//
// This is part of the TransactionSubscription interface.
func (t *txSubscriptionClient) ConfirmedTransactions() chan *lnwallet.TransactionDetail {
return t.confirmed
}
// UnconfirmedTransactions returns a channel which will be sent on as
// new relevant transactions are seen within the network.
//
// This is part of the TransactionSubscription interface.
func (t *txSubscriptionClient) UnconfirmedTransactions() chan *lnwallet.TransactionDetail {
return t.unconfirmed
}
// Cancel finalizes the subscription, cleaning up any resources allocated.
//
// This is part of the TransactionSubscription interface.
func (t *txSubscriptionClient) Cancel() {
close(t.quit)
t.wg.Wait()
t.txClient.Done()
}
// notificationProxier proxies the notifications received by the underlying
// wallet's notification client to a higher-level TransactionSubscription
// client.
func (t *txSubscriptionClient) notificationProxier() {
out:
for {
select {
case txNtfn := <-t.txClient.C:
// TODO(roasbeef): handle detached blocks
currentHeight := t.w.Manager.SyncedTo().Height
// Launch a goroutine to re-package and send
// notifications for any newly confirmed transactions.
go func() {
for _, block := range txNtfn.AttachedBlocks {
details, err := minedTransactionsToDetails(currentHeight, block, t.w.ChainParams())
if err != nil {
continue
}
for _, d := range details {
select {
case t.confirmed <- d:
case <-t.quit:
return
}
}
}
}()
// Launch a goroutine to re-package and send
// notifications for any newly unconfirmed transactions.
go func() {
for _, tx := range txNtfn.UnminedTransactions {
detail, err := unminedTransactionsToDetail(
tx, t.w.ChainParams(),
)
if err != nil {
continue
}
select {
case t.unconfirmed <- detail:
case <-t.quit:
return
}
}
}()
case <-t.quit:
break out
}
}
t.wg.Done()
}
// SubscribeTransactions returns a TransactionSubscription client which
// is capable of receiving async notifications as new transactions
// related to the wallet are seen within the network, or found in
// blocks.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) SubscribeTransactions() (lnwallet.TransactionSubscription, error) {
walletClient := b.wallet.NtfnServer.TransactionNotifications()
txClient := &txSubscriptionClient{
txClient: walletClient,
confirmed: make(chan *lnwallet.TransactionDetail),
unconfirmed: make(chan *lnwallet.TransactionDetail),
w: b.wallet,
quit: make(chan struct{}),
}
txClient.wg.Add(1)
go txClient.notificationProxier()
return txClient, nil
}
// IsSynced returns a boolean indicating if from the PoV of the wallet, it has
// fully synced to the current best block in the main chain.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) IsSynced() (bool, int64, error) {
// Grab the best chain state the wallet is currently aware of.
syncState := b.wallet.Manager.SyncedTo()
// We'll also extract the current best wallet timestamp so the caller
// can get an idea of where we are in the sync timeline.
bestTimestamp := syncState.Timestamp.Unix()
// Next, query the chain backend to grab the info about the tip of the
// main chain.
bestHash, bestHeight, err := b.cfg.ChainSource.GetBestBlock()
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if err != nil {
return false, 0, err
}
// If the wallet hasn't yet fully synced to the node's best chain tip,
// then we're not yet fully synced.
if syncState.Height < bestHeight || !b.wallet.ChainSynced() {
return false, bestTimestamp, nil
}
// If the wallet is on par with the current best chain tip, then we
// still may not yet be synced as the chain backend may still be
// catching up to the main chain. So we'll grab the block header in
// order to make a guess based on the current time stamp.
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blockHeader, err := b.cfg.ChainSource.GetBlockHeader(bestHash)
if err != nil {
return false, 0, err
}
// If the timestamp on the best header is more than 2 hours in the
// past, then we're not yet synced.
minus24Hours := time.Now().Add(-2 * time.Hour)
if blockHeader.Timestamp.Before(minus24Hours) {
return false, bestTimestamp, nil
}
return true, bestTimestamp, nil
}