package lnwallet import ( "errors" "fmt" "sync" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/txscript" "github.com/roasbeef/btcd/wire" "github.com/roasbeef/btcutil" ) // ErrNotMine is an error denoting that a WalletController instance is unable // to spend a specifid output. var ErrNotMine = errors.New("the passed output doesn't belong to the wallet") // AddressType is a enum-like type which denotes the possible address types // WalletController supports. type AddressType uint8 const ( // WitnessPubKey represents a p2wkh address. WitnessPubKey AddressType = iota // NestedWitnessPubKey represents a p2sh output which is itself a // nested p2wkh output. NestedWitnessPubKey // PublicKey represents a regular p2pkh output. PubKeyHash ) // Utxo is an unspent output denoted by its outpoint, and output value of the // original output. type Utxo struct { Value btcutil.Amount wire.OutPoint } // WalletController defines an abstract interface for controlling a local Pure // Go wallet, a local or remote wallet via an RPC mechanism, or possibly even // a daemon assisted hardware wallet. This interface serves the purpose of // allowing LightningWallet to be seamlessly compatible with several wallets // such as: uspv, btcwallet, Bitcoin Core, Electrum, etc. This interface then // serves as a "base wallet", with Lightning Network awareness taking place at // a "higher" level of abstraction. Essentially, an overlay wallet. // Implementors of this interface must closely adhere to the documented // behavior of all interface methods in order to ensure identical behavior // across all concrete implementations. type WalletController interface { // FetchInputInfo queries for the WalletController's knowledge of the // passed outpoint. If the base wallet determines this output is under // its control, then the original txout should be returned. Otherwise, // a non-nil error value of ErrNotMine should be returned instead. FetchInputInfo(prevOut *wire.OutPoint) (*wire.TxOut, error) // 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. ConfirmedBalance(confs int32, witness bool) (btcutil.Amount, error) // 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 should be used, otherwise an external // address should be returned. The type of address returned is dictated // by the wallet's capabilities, and may be of type: p2sh, p2pkh, // p2wkh, p2wsh, etc. NewAddress(addrType AddressType, change bool) (btcutil.Address, error) // GetPrivKey retrives the underlying private key associated with the // passed address. If the wallet is unable to locate this private key // due to the address not being under control of the wallet, then an // error should be returned. // TODO(roasbeef): should instead take tadge's derivation scheme in GetPrivKey(a btcutil.Address) (*btcec.PrivateKey, error) // NewRawKey returns a raw private key controlled by the wallet. These // keys are used for the 2-of-2 multi-sig outputs for funding // transactions, as well as the pub key used for commitment transactions. // TODO(roasbeef): may be scrapped, see above TODO NewRawKey() (*btcec.PublicKey, error) // FetchRootKey returns a root key which will be used by the // LightningWallet to deterministically generate secrets. The private // key returned by this method should remain constant in-between // WalletController restarts. FetchRootKey() (*btcec.PrivateKey, error) // 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, and error // should be returned. SendOutputs(outputs []*wire.TxOut) (*wire.ShaHash, error) // ListUnspentWitness returns all unspent outputs which are version 0 // witness programs. The 'confirms' parameter indicates the minimum // number of confirmations an output needs in order to be returned by // this method. Passing -1 as 'confirms' indicates that even // unconfirmed outputs should be returned. ListUnspentWitness(confirms int32) ([]*Utxo, error) // 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. LockOutpoint(o wire.OutPoint) // UnlockOutpoint unlocks an previously locked output, marking it // eligible for coin seleciton. UnlockOutpoint(o wire.OutPoint) // PublishTransaction performs cursory validation (dust checks, etc), // then finally broadcasts the passed transaction to the Bitcoin network. PublishTransaction(tx *wire.MsgTx) error // Start initializes the wallet, making any neccessary connections, // starting up required goroutines etc. Start() error // Stop signals the wallet for shutdown. Shutdown may entail closing // any active sockets, database handles, stopping goroutines, etc. Stop() error } // BlockChainIO is a dedicated source which will be used to obtain queries // related to the current state of the blockchain. The data returned by each of // the defined methods within this interface should always return the most up // to date data possible. // // TODO(roasbeef): move to diff package perhaps? type BlockChainIO interface { // GetCurrentHeight returns the current height of the valid most-work // chain the implementation is aware of. GetCurrentHeight() (int32, error) // GetTxOut returns the original output referenced by the passed // outpoint. GetUtxo(txid *wire.ShaHash, index uint32) (*wire.TxOut, error) // GetTransaction returns the full transaction identified by the passed // transaction ID. GetTransaction(txid *wire.ShaHash) (*wire.MsgTx, error) } // SignDescriptor houses the necessary information required to succesfully sign // a given output. This struct is used by the Signer interface in order to gain // access to critial data needed to generate a valid signature. type SignDescriptor struct { // Pubkey is the public key to which the signature should be generated // over. The Signer should then generate a signature with the private // key corresponding to this public key. PubKey *btcec.PublicKey // RedeemScript is the full script required to properly redeem the // output. This field will only be populated if a p2wsh or a p2sh // output is being signed. RedeemScript []byte // Output is the target output which should be signed. The PkScript and // Value fields within the output should be properly populated, // otherwise an invalid signature may be generated. Output *wire.TxOut // HashType is the target sighash type that should be used when // generating the final sighash, and signature. HashType txscript.SigHashType // SigHashes is the pre-computed sighash midstate to be used when // generating the final sighash for signing. SigHashes *txscript.TxSigHashes // InputIndex is the target input within the transaction that should be // signed. InputIndex int } // Signer represents an abstract object capable of generating raw signatures as // well as full complete input scripts given a valid SignDescriptor and // transaction. This interface fully abstracts away signing paving the way for // Signer implementations such as hardware wallets, hardware tokens, HSM's, or // simply a regular wallet. type Signer interface { // SignOutputRaw generates a signature for the passed transaction // according to the data within the passed SignDescriptor. // // NOTE: The resulting signature should be void of a sighash byte. SignOutputRaw(tx *wire.MsgTx, signDesc *SignDescriptor) ([]byte, error) // ComputeInputScript generates a complete InputIndex for the passed // transaction with the signature as defined within the passed // SignDescriptor. This method should be capable of generating the // proper input script for both regular p2wkh output and p2wkh outputs // nested within a regualr p2sh output. ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*InputScript, error) } // WalletDriver represents a "driver" for a particular concrete // WalletController implementation. A driver is indentified by a globally // unique string identifier along with a 'New()' method which is responsible // for initializing a particular WalletController concrete implementation. type WalletDriver struct { // WalletType is a string which uniquely identifes the WalletController // that this driver, drives. WalletType string // New creates a new instance of a concrete WalletController // implementation given a variadic set up arguments. The function takes // a varidaic number of interface paramters in order to provide // initialization flexibility, thereby accomodating several potential // WalletController implementations. New func(args ...interface{}) (WalletController, error) } var ( wallets = make(map[string]*WalletDriver) registerMtx sync.Mutex ) // RegisteredWallets returns a slice of all currently registered notifiers. // // NOTE: This function is safe for concurrent access. func RegisteredWallets() []*WalletDriver { registerMtx.Lock() defer registerMtx.Unlock() registeredWallets := make([]*WalletDriver, 0, len(wallets)) for _, wallet := range wallets { registeredWallets = append(registeredWallets, wallet) } return registeredWallets } // RegisterWallet registers a WalletDriver which is capable of driving a // concrete WalletController interface. In the case that this driver has // already been registered, an error is returned. // // NOTE: This function is safe for concurrent access. func RegisterWallet(driver *WalletDriver) error { registerMtx.Lock() defer registerMtx.Unlock() if _, ok := wallets[driver.WalletType]; ok { return fmt.Errorf("wallet already registered") } wallets[driver.WalletType] = driver return nil } // SupportedWallets returns a slice of strings that represents the walelt // drivers that have been registered and are therefore supported. // // NOTE: This function is safe for concurrent access. func SupportedWallets() []string { registerMtx.Lock() defer registerMtx.Unlock() supportedWallets := make([]string, 0, len(wallets)) for walletName := range wallets { supportedWallets = append(supportedWallets, walletName) } return supportedWallets }