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/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 interface. var _ lnwallet.WalletController = (*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()) return b.wallet.SendOutputs(outputs, defaultAccount, 1, feeSatPerKB) } // 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 } var addressType lnwallet.AddressType 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, } 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, } 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 }