lnd.xprv/lnwallet/btcwallet/btcwallet.go
Olaoluwa Osuntokun eaa043f585 lnwallet/btcwallet: use relay fee not tx fee rate for dust check
In this commit we fix a hidden bug in the transaction creating logic
that was only manifested recently due to higher fees on Bitcoin's
mainnet. Before this commit, we would use the target fee rate to
determine if an output was dust or not. However, this is incorrect, as
instead the relay fee should be used as this matches the policy checks
widely deployed in Bitcoin full node today.

To fix this issue we now properly use the relay fee when computing dust.
This fixes the issue for the `EstimateFee` call, but the `SendOutputs`
call also has a similar issue. However, this must be fixed within
`btcwallet` itself, so it has been left out of this commit

Fixes #3217.
2019-06-18 19:55:16 -07:00

793 lines
24 KiB
Go

package btcwallet
import (
"bytes"
"encoding/hex"
"fmt"
"math"
"strings"
"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
// utxoCache is a cache used to speed up repeated calls to
// FetchInputInfo.
utxoCache map[wire.OutPoint]*wire.TxOut
cacheMtx sync.RWMutex
}
// 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.
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.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,
utxoCache: make(map[wire.OutPoint]*wire.TxOut),
}, nil
}
// 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)
}
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
// 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)
}
// 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 {
switch b.chain.(type) {
case *chain.RPCClient:
if strings.Contains(err.Error(), "already spent") {
// Output was already spent.
return lnwallet.ErrDoubleSpend
}
if strings.Contains(err.Error(), "already been spent") {
// Output was already spent.
return lnwallet.ErrDoubleSpend
}
if strings.Contains(err.Error(), "orphan transaction") {
// Transaction is spending either output that
// is missing or already spent.
return lnwallet.ErrDoubleSpend
}
case *chain.BitcoindClient:
if strings.Contains(err.Error(), "txn-mempool-conflict") {
// Output was spent by other transaction
// already in the mempool.
return lnwallet.ErrDoubleSpend
}
if strings.Contains(err.Error(), "insufficient fee") {
// RBF enabled transaction did not have enough fee.
return lnwallet.ErrDoubleSpend
}
if strings.Contains(err.Error(), "Missing inputs") {
// Transaction is spending either output that
// is missing or already spent.
return lnwallet.ErrDoubleSpend
}
case *chain.NeutrinoClient:
if strings.Contains(err.Error(), "already spent") {
// Output was already spent.
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
// for an unconfirmed transaction to a transaction detail.
func unminedTransactionsToDetail(
summary base.TransactionSummary,
) (*lnwallet.TransactionDetail, error) {
wireTx := &wire.MsgTx{}
txReader := bytes.NewReader(summary.Transaction)
if err := wireTx.Deserialize(txReader); err != nil {
return nil, err
}
txDetail := &lnwallet.TransactionDetail{
Hash: *summary.Hash,
TotalFees: int64(summary.Fee),
Timestamp: summary.Timestamp,
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)
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)
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()
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.
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
}