lnd.xprv/lnwallet/btcwallet/btcwallet.go
Olaoluwa Osuntokun 628224a5ee
lnwallet/btcwallet: concretely implement the new TransactionSubscription interface
This commit returns the BtcWallet wrapper struct back to conformance to
the WalletController interface by adding support for
SubscribeTransactions.

The implementation of the lnwallet.TransactionSubscription consists
simply of a proxy goroutine which forwards notifications from the
wallet’s internal NotificaitonServer.
2016-10-15 14:11:25 -07:00

613 lines
18 KiB
Go

package btcwallet
import (
"bytes"
"encoding/hex"
"fmt"
"math"
"sync"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/chaincfg"
"github.com/roasbeef/btcd/txscript"
"github.com/roasbeef/btcd/wire"
"github.com/roasbeef/btcutil"
"github.com/roasbeef/btcwallet/chain"
"github.com/roasbeef/btcwallet/waddrmgr"
base "github.com/roasbeef/btcwallet/wallet"
"github.com/roasbeef/btcwallet/walletdb"
)
const (
defaultAccount = uint32(waddrmgr.DefaultAccountNum)
)
var (
lnNamespace = []byte("ln")
rootKey = []byte("ln-root")
)
// 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
// rpc is an an active RPC connection to btcd full-node.
rpc *chain.RPCClient
// lnNamespace is a namespace within btcwallet's walletdb used to store
// persistent state required by the WalletController interface but not
// natively supported by btcwallet.
lnNamespace walletdb.Namespace
netParams *chaincfg.Params
// 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 interface.
var _ lnwallet.WalletController = (*BtcWallet)(nil)
// New returns a new fully initialized instance of BtcWallet given a valid
// confirguration 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)
var pubPass []byte
if cfg.PublicPass == nil {
pubPass = defaultPubPassphrase
} else {
pubPass = cfg.PublicPass
}
loader := base.NewLoader(cfg.NetParams, netDir)
walletExists, err := loader.WalletExists()
if err != nil {
return nil, err
}
var wallet *base.Wallet
if !walletExists {
// Wallet has never been created, perform initial set up.
wallet, err = loader.CreateNewWallet(pubPass, cfg.PrivatePass,
cfg.HdSeed)
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 namepsaces, and the DB itself.
wallet, err = loader.OpenExistingWallet(pubPass, false)
if err != nil {
return nil, err
}
}
if err := wallet.Manager.Unlock(cfg.PrivatePass); err != nil {
return nil, err
}
// Create a special websockets rpc client for btcd which will be used
// by the wallet for notifications, calls, etc.
rpcc, err := chain.NewRPCClient(cfg.NetParams, cfg.RpcHost,
cfg.RpcUser, cfg.RpcPass, cfg.CACert, false, 20)
if err != nil {
return nil, err
}
db := wallet.Database()
walletNamespace, err := db.Namespace(lnNamespace)
if err != nil {
return nil, err
}
return &BtcWallet{
wallet: wallet,
rpc: rpcc,
lnNamespace: walletNamespace,
netParams: cfg.NetParams,
utxoCache: make(map[wire.OutPoint]*wire.TxOut),
}, nil
}
// 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 {
// Establish an RPC connection in additino to starting the goroutines
// in the underlying wallet.
if err := b.rpc.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.rpc)
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.rpc.Shutdown()
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, witness bool) (btcutil.Amount, error) {
var balance btcutil.Amount
if witness {
witnessOutputs, err := b.ListUnspentWitness(confs)
if err != nil {
return 0, err
}
for _, witnessOutput := range witnessOutputs {
balance += witnessOutput.Value
}
} else {
outputSum, err := b.wallet.CalculateBalance(confs)
if err != nil {
return 0, err
}
balance = outputSum
}
return balance, nil
}
// NewAddress returns the next external or internal address for the wallet
// dicatated by the value of the `change` paramter. 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 addrType waddrmgr.AddressType
switch t {
case lnwallet.WitnessPubKey:
addrType = waddrmgr.WitnessPubKey
case lnwallet.NestedWitnessPubKey:
addrType = waddrmgr.NestedWitnessPubKey
case lnwallet.PubKeyHash:
addrType = waddrmgr.PubKeyHash
default:
return nil, fmt.Errorf("unknown address type")
}
if change {
return b.wallet.NewAddress(defaultAccount, addrType)
} else {
return b.wallet.NewChangeAddress(defaultAccount, addrType)
}
}
// GetPrivKey retrives the underlying private key associated with the passed
// address. If the we're unable to locate the proper private key, then a
// non-nil error will be returned.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) GetPrivKey(a btcutil.Address) (*btcec.PrivateKey, error) {
// Using the ID address, request the private key coresponding to the
// address from the wallet's address manager.
walletAddr, err := b.wallet.Manager.Address(a)
if err != nil {
return nil, err
}
return walletAddr.(waddrmgr.ManagedPubKeyAddress).PrivKey()
}
// NewRawKey retrieves the next key within our HD key-chain for use within as a
// multi-sig key within the funding transaction, or within the commitment
// transaction's outputs.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) NewRawKey() (*btcec.PublicKey, error) {
nextAddr, err := b.wallet.Manager.NextExternalAddresses(defaultAccount,
1, waddrmgr.WitnessPubKey)
if err != nil {
return nil, err
}
pkAddr := nextAddr[0].(waddrmgr.ManagedPubKeyAddress)
return pkAddr.PubKey(), nil
}
// FetchRootKey returns a root key which is meanted to be used as an initial
// seed/salt to generate any Lightning specific secrets.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) FetchRootKey() (*btcec.PrivateKey, error) {
// Fetch the root address hash from the database, this is persisted
// locally within the database, then used to obtain the key from the
// wallet based on the address hash.
var rootAddrHash []byte
if err := b.lnNamespace.Update(func(tx walletdb.Tx) error {
rootBucket := tx.RootBucket()
rootAddrHash = rootBucket.Get(rootKey)
return nil
}); err != nil {
return nil, err
}
if rootAddrHash == nil {
// Otherwise, we need to generate a fresh address from the
// wallet, then stores it's hash160 within the database so we
// can look up the exact key later.
rootAddr, err := b.wallet.Manager.NextExternalAddresses(defaultAccount,
1, waddrmgr.WitnessPubKey)
if err != nil {
return nil, err
}
if err := b.lnNamespace.Update(func(tx walletdb.Tx) error {
rootBucket := tx.RootBucket()
rootAddrHash = rootAddr[0].Address().ScriptAddress()
if err := rootBucket.Put(rootKey, rootAddrHash); err != nil {
return err
}
return nil
}); err != nil {
return nil, err
}
}
// With the root address hash obtained, generate the corresponding
// address, then retrieve the managed address from the wallet which
// will allow us to obtain the private key.
rootAddr, err := btcutil.NewAddressWitnessPubKeyHash(rootAddrHash,
b.netParams)
if err != nil {
return nil, err
}
walletAddr, err := b.wallet.Manager.Address(rootAddr)
if err != nil {
return nil, err
}
return walletAddr.(waddrmgr.ManagedPubKeyAddress).PrivKey()
}
// 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 be returned.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) SendOutputs(outputs []*wire.TxOut) (*wire.ShaHash, error) {
return b.wallet.SendOutputs(outputs, defaultAccount, 1)
}
// 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 an previously locked output, marking it eligible for
// coin seleciton.
//
// 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 int32) ([]*lnwallet.Utxo, error) {
// First, grab all the unfiltered currently unspent outputs.
maxConfs := int32(math.MaxInt32)
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
}
// TODO(roasbeef): this assumes all p2sh outputs returned by
// the wallet are nested p2sh...
if txscript.IsPayToWitnessPubKeyHash(pkScript) ||
txscript.IsPayToScriptHash(pkScript) {
txid, err := wire.NewShaHashFromStr(output.TxID)
if err != nil {
return nil, err
}
utxo := &lnwallet.Utxo{
Value: btcutil.Amount(output.Amount * 1e8),
OutPoint: wire.OutPoint{
Hash: *txid,
Index: output.Vout,
},
}
witnessOutputs = append(witnessOutputs, utxo)
}
}
return witnessOutputs, nil
}
// PublishTransaction performs cursory validation (dust checks, etc), then
// finally broadcasts the passed transaction to the Bitcoin network.
func (b *BtcWallet) PublishTransaction(tx *wire.MsgTx) error {
return b.wallet.PublishTransaction(tx)
}
// extractBalanceDelta extracts the net balance delta from the PoV of the
// wallet given a TransactionSummary.
func extractBalanceDelta(txSummary base.TransactionSummary) (btcutil.Amount, error) {
tx := wire.NewMsgTx()
txReader := bytes.NewReader(txSummary.Transaction)
if err := tx.Deserialize(txReader); err != nil {
return -1, nil
}
// 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) ([]*lnwallet.TransactionDetail, error) {
details := make([]*lnwallet.TransactionDetail, 0, len(block.Transactions))
for _, tx := range block.Transactions {
txDetail := &lnwallet.TransactionDetail{
Hash: *tx.Hash,
NumConfirmations: currentHeight - block.Height + 1,
BlockHash: block.Hash,
BlockHeight: block.Height,
Timestamp: block.Timestamp,
TotalFees: int64(tx.Fee),
}
balanceDelta, err := extractBalanceDelta(tx)
if err != nil {
return nil, err
}
txDetail.Value = balanceDelta
details = append(details, txDetail)
}
return details, nil
}
// unminedTransactionsToDetail is a helper funciton which converts a summary
// for a unconfirmed transaction to a transaction detail.
func unminedTransactionsToDetail(summary base.TransactionSummary) (*lnwallet.TransactionDetail, error) {
txDetail := &lnwallet.TransactionDetail{
Hash: *summary.Hash,
TotalFees: int64(summary.Fee),
Timestamp: summary.Timestamp,
}
balanceDelta, err := extractBalanceDelta(summary)
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
// TODO(roasbeef): can replace with start "wallet birthday"
start := base.NewBlockIdentifierFromHeight(0)
stop := base.NewBlockIdentifierFromHeight(bestBlock.Height)
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 unconfirme dtransactions, create a
// TransactionDetail which re-packages the data returned by the base
// wallet.
for _, blockPackage := range txns.MinedTransactions {
details, err := minedTransactionsToDetails(currentHeight, blockPackage)
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)
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
}