Merge pull request #17 from lightningnetwork/wallet-interface-refactor

Refactor the lnwallet package to directly use the WalletController interface

channeldb/channel.go

@@ -106,7 +106,7 @@ type OpenChannel struct {
 	//ReserveAmount btcutil.Amount
 
 	// Keys for both sides to be used for the commitment transactions.
-	OurCommitKey   *btcec.PrivateKey
+	OurCommitKey   *btcec.PublicKey
 	TheirCommitKey *btcec.PublicKey
 
 	// Tracking total channel capacity, and the amount of funds allocated
@@ -123,7 +123,7 @@ type OpenChannel struct {
 	// The outpoint of the final funding transaction.
 	FundingOutpoint *wire.OutPoint
 
-	OurMultiSigKey      *btcec.PrivateKey
+	OurMultiSigKey      *btcec.PublicKey
 	TheirMultiSigKey    *btcec.PublicKey
 	FundingRedeemScript []byte
 
@@ -200,7 +200,7 @@ func (c *OpenChannel) FullSync() error {
 			chanIDBucket.Put(b.Bytes(), nil)
 		}
 
-		return putOpenChannel(chanBucket, nodeChanBucket, c, c.Db.cryptoSystem)
+		return putOpenChannel(chanBucket, nodeChanBucket, c)
 	})
 }
 
@@ -362,7 +362,7 @@ func putClosedChannelSummary(tx *bolt.Tx, chanID []byte) error {
 // putChannel serializes, and stores the current state of the channel in its
 // entirety.
 func putOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
-	channel *OpenChannel, encryptor EncryptorDecryptor) error {
+	channel *OpenChannel) error {
 
 	// First write out all the "common" fields using the field's prefix
 	// appened with the channel's ID. These fields go into a top-level bucket
@@ -387,13 +387,13 @@ func putOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
 	if err := putChannelIDs(nodeChanBucket, channel); err != nil {
 		return err
 	}
-	if err := putChanCommitKeys(nodeChanBucket, channel, encryptor); err != nil {
+	if err := putChanCommitKeys(nodeChanBucket, channel); err != nil {
 		return err
 	}
 	if err := putChanCommitTxns(nodeChanBucket, channel); err != nil {
 		return err
 	}
-	if err := putChanFundingInfo(nodeChanBucket, channel, encryptor); err != nil {
+	if err := putChanFundingInfo(nodeChanBucket, channel); err != nil {
 		return err
 	}
 	if err := putChanEklremState(nodeChanBucket, channel); err != nil {
@@ -411,7 +411,7 @@ func putOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
 // An EncryptorDecryptor is required to decrypt sensitive information stored
 // within the database.
 func fetchOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
-	chanID *wire.OutPoint, decryptor EncryptorDecryptor) (*OpenChannel, error) {
+	chanID *wire.OutPoint) (*OpenChannel, error) {
 
 	channel := &OpenChannel{
 		ChanID: chanID,
@@ -421,13 +421,13 @@ func fetchOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
 	if err := fetchChannelIDs(nodeChanBucket, channel); err != nil {
 		return nil, err
 	}
-	if err := fetchChanCommitKeys(nodeChanBucket, channel, decryptor); err != nil {
+	if err := fetchChanCommitKeys(nodeChanBucket, channel); err != nil {
 		return nil, err
 	}
 	if err := fetchChanCommitTxns(nodeChanBucket, channel); err != nil {
 		return nil, err
 	}
-	if err := fetchChanFundingInfo(nodeChanBucket, channel, decryptor); err != nil {
+	if err := fetchChanFundingInfo(nodeChanBucket, channel); err != nil {
 		return nil, err
 	}
 	if err := fetchChanEklremState(nodeChanBucket, channel); err != nil {
@@ -791,8 +791,7 @@ func fetchChannelIDs(nodeChanBucket *bolt.Bucket, channel *OpenChannel) error {
 	return nil
 }
 
-func putChanCommitKeys(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
-	ed EncryptorDecryptor) error {
+func putChanCommitKeys(nodeChanBucket *bolt.Bucket, channel *OpenChannel) error {
 
 	// Construct the key which stores the commitment keys: ckk || channelID.
 	// TODO(roasbeef): factor into func
@@ -810,12 +809,7 @@ func putChanCommitKeys(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
 		return err
 	}
 
-	encryptedPriv, err := ed.Encrypt(channel.OurCommitKey.Serialize())
-	if err != nil {
-		return err
-	}
-
-	if _, err := b.Write(encryptedPriv); err != nil {
+	if _, err := b.Write(channel.OurCommitKey.SerializeCompressed()); err != nil {
 		return err
 	}
 
@@ -829,8 +823,7 @@ func deleteChanCommitKeys(nodeChanBucket *bolt.Bucket, chanID []byte) error {
 	return nodeChanBucket.Delete(commitKey)
 }
 
-func fetchChanCommitKeys(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
-	ed EncryptorDecryptor) error {
+func fetchChanCommitKeys(nodeChanBucket *bolt.Bucket, channel *OpenChannel) error {
 
 	// Construct the key which stores the commitment keys: ckk || channelID.
 	// TODO(roasbeef): factor into func
@@ -850,12 +843,7 @@ func fetchChanCommitKeys(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
 		return err
 	}
 
-	decryptedPriv, err := ed.Decrypt(keyBytes[33:])
-	if err != nil {
-		return err
-	}
-
-	channel.OurCommitKey, _ = btcec.PrivKeyFromBytes(btcec.S256(), decryptedPriv)
+	channel.OurCommitKey, err = btcec.ParsePubKey(keyBytes[33:], btcec.S256())
 	if err != nil {
 		return err
 	}
@@ -939,9 +927,7 @@ func fetchChanCommitTxns(nodeChanBucket *bolt.Bucket, channel *OpenChannel) erro
 	return nil
 }
 
-func putChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
-	ed EncryptorDecryptor) error {
-
+func putChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel) error {
 	var bc bytes.Buffer
 	if err := writeOutpoint(&bc, channel.ChanID); err != nil {
 		return err
@@ -956,11 +942,8 @@ func putChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
 		return err
 	}
 
-	encryptedPriv, err := ed.Encrypt(channel.OurMultiSigKey.Serialize())
-	if err != nil {
-		return err
-	}
-	if err := wire.WriteVarBytes(&b, 0, encryptedPriv); err != nil {
+	ourSerKey := channel.OurMultiSigKey.SerializeCompressed()
+	if err := wire.WriteVarBytes(&b, 0, ourSerKey); err != nil {
 		return err
 	}
 	theirSerKey := channel.TheirMultiSigKey.SerializeCompressed()
@@ -989,9 +972,7 @@ func deleteChanFundingInfo(nodeChanBucket *bolt.Bucket, chanID []byte) error {
 	return nodeChanBucket.Delete(fundTxnKey)
 }
 
-func fetchChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
-	ed EncryptorDecryptor) error {
-
+func fetchChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel) error {
 	var b bytes.Buffer
 	if err := writeOutpoint(&b, channel.ChanID); err != nil {
 		return err
@@ -1008,17 +989,16 @@ func fetchChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel,
 		return err
 	}
 
-	encryptedPrivBytes, err := wire.ReadVarBytes(infoBytes, 0, 100, "")
+	ourKeyBytes, err := wire.ReadVarBytes(infoBytes, 0, 34, "")
 	if err != nil {
 		return err
 	}
-	decryptedPriv, err := ed.Decrypt(encryptedPrivBytes)
+	channel.OurMultiSigKey, err = btcec.ParsePubKey(ourKeyBytes, btcec.S256())
 	if err != nil {
 		return err
 	}
-	channel.OurMultiSigKey, _ = btcec.PrivKeyFromBytes(btcec.S256(), decryptedPriv)
 
-	theirKeyBytes, err := wire.ReadVarBytes(infoBytes, 0, 33, "")
+	theirKeyBytes, err := wire.ReadVarBytes(infoBytes, 0, 34, "")
 	if err != nil {
 		return err
 	}

channeldb/channel_test.go

@@ -78,23 +78,6 @@ var (
 	}
 )
 
-type MockEncryptorDecryptor struct {
-}
-
-func (m *MockEncryptorDecryptor) Encrypt(n []byte) ([]byte, error) {
-	return n, nil
-}
-
-func (m *MockEncryptorDecryptor) Decrypt(n []byte) ([]byte, error) {
-	return n, nil
-}
-
-func (m *MockEncryptorDecryptor) OverheadSize() uint32 {
-	return 0
-}
-
-var _ EncryptorDecryptor = (*MockEncryptorDecryptor)(nil)
-
 func TestOpenChannelPutGetDelete(t *testing.T) {
 	// First, create a temporary directory to be used for the duration of
 	// this test.
@@ -111,7 +94,6 @@ func TestOpenChannelPutGetDelete(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unable to create channeldb: %v", err)
 	}
-	cdb.RegisterCryptoSystem(&MockEncryptorDecryptor{})
 	defer cdb.Close()
 
 	privKey, pubKey := btcec.PrivKeyFromBytes(btcec.S256(), key[:])
@@ -144,7 +126,7 @@ func TestOpenChannelPutGetDelete(t *testing.T) {
 		TheirLNID:                  key,
 		ChanID:                     id,
 		MinFeePerKb:                btcutil.Amount(5000),
-		OurCommitKey:               privKey,
+		OurCommitKey:               privKey.PubKey(),
 		TheirCommitKey:             pubKey,
 		Capacity:                   btcutil.Amount(10000),
 		OurBalance:                 btcutil.Amount(3000),
@@ -154,7 +136,7 @@ func TestOpenChannelPutGetDelete(t *testing.T) {
 		LocalElkrem:                sender,
 		RemoteElkrem:               receiver,
 		FundingOutpoint:            testOutpoint,
-		OurMultiSigKey:             privKey,
+		OurMultiSigKey:             privKey.PubKey(),
 		TheirMultiSigKey:           privKey.PubKey(),
 		FundingRedeemScript:        script,
 		TheirCurrentRevocation:     privKey.PubKey(),
@@ -195,8 +177,8 @@ func TestOpenChannelPutGetDelete(t *testing.T) {
 		t.Fatalf("fee/kb doens't match")
 	}
 
-	if !bytes.Equal(state.OurCommitKey.Serialize(),
-		newState.OurCommitKey.Serialize()) {
+	if !bytes.Equal(state.OurCommitKey.SerializeCompressed(),
+		newState.OurCommitKey.SerializeCompressed()) {
 		t.Fatalf("our commit key dont't match")
 	}
 	if !bytes.Equal(state.TheirCommitKey.SerializeCompressed(),
@@ -234,8 +216,8 @@ func TestOpenChannelPutGetDelete(t *testing.T) {
 		t.Fatalf("funding outpoint doesn't match")
 	}
 
-	if !bytes.Equal(state.OurMultiSigKey.Serialize(),
-		newState.OurMultiSigKey.Serialize()) {
+	if !bytes.Equal(state.OurMultiSigKey.SerializeCompressed(),
+		newState.OurMultiSigKey.SerializeCompressed()) {
 		t.Fatalf("our multisig key doesn't match")
 	}
 	if !bytes.Equal(state.TheirMultiSigKey.SerializeCompressed(),

channeldb/db.go

@@ -27,14 +27,6 @@ var bufPool = &sync.Pool{
 	New: func() interface{} { return new(bytes.Buffer) },
 }
 
-// EncryptorDecryptor...
-// TODO(roasbeef): ability to rotate EncryptorDecryptor's across DB
-type EncryptorDecryptor interface {
-	Encrypt(in []byte) ([]byte, error)
-	Decrypt(in []byte) ([]byte, error)
-	OverheadSize() uint32
-}
-
 // DB is the primary datastore for the LND daemon. The database stores
 // information related to nodes, routing data, open/closed channels, fee
 // schedules, and reputation data.
@@ -42,8 +34,6 @@ type DB struct {
 	store *bolt.DB
 
 	netParams *chaincfg.Params
-
-	cryptoSystem EncryptorDecryptor
 }
 
 // Open opens an existing channeldb created under the passed namespace with
@@ -66,12 +56,6 @@ func Open(dbPath string, netParams *chaincfg.Params) (*DB, error) {
 	return &DB{store: bdb, netParams: netParams}, nil
 }
 
-// RegisterCryptoSystem registers an implementation of the EncryptorDecryptor
-// interface for use within the database to encrypt/decrypt sensitive data.
-func (d *DB) RegisterCryptoSystem(ed EncryptorDecryptor) {
-	d.cryptoSystem = ed
-}
-
 // Wipe completely deletes all saved state within all used buckets within the
 // database. The deletion is done in a single transaction, therefore this
 // operation is fully atomic.
@@ -179,7 +163,7 @@ func (d *DB) FetchOpenChannels(nodeID *wire.ShaHash) ([]*OpenChannel, error) {
 			}
 
 			oChannel, err := fetchOpenChannel(openChanBucket,
-				nodeChanBucket, chanID, d.cryptoSystem)
+				nodeChanBucket, chanID)
 			if err != nil {
 				return err
 			}

fundingmanager.go

@@ -469,7 +469,6 @@ func (f *fundingManager) handleFundingComplete(fmsg *fundingCompleteMsg) {
 	// Append a sighash type of SigHashAll to the signature as it's the
 	// sighash type used implicitly within this type of channel for
 	// commitment transactions.
-	commitSig = append(commitSig, byte(txscript.SigHashAll))
 	revokeKey := fmsg.msg.RevocationKey
 	if err := resCtx.reservation.CompleteReservationSingle(revokeKey, fundingOut, commitSig); err != nil {
 		// TODO(roasbeef): better error logging: peerID, channelID, etc.
@@ -521,7 +520,7 @@ func (f *fundingManager) handleFundingSignComplete(fmsg *fundingSignCompleteMsg)
 	// The remote peer has responded with a signature for our commitment
 	// transaction. We'll verify the signature for validity, then commit
 	// the state to disk as we can now open the channel.
-	commitSig := append(fmsg.msg.CommitSignature.Serialize(), byte(txscript.SigHashAll))
+	commitSig := fmsg.msg.CommitSignature.Serialize()
 	if err := resCtx.reservation.CompleteReservation(nil, commitSig); err != nil {
 		fndgLog.Errorf("unable to complete reservation sign complete: %v", err)
 		fmsg.peer.Disconnect()

glide.lock

@@ -1,5 +1,5 @@
-hash: 348cab6c25a05211caed34dc711bd1cb5a51800bc87d3609127ff9271b206c42
-updated: 2016-09-02T08:34:25.843272647-04:00
+hash: d11bb1bf4ed6df842559ffff8fcf859509382395ba38fc29a0de546526ecbcd4
+updated: 2016-09-08T12:08:13.98576317-07:00
 imports:
 - name: github.com/awalterschulze/gographviz
   version: cafbade2d58068c3992f12afe46742195c673d2b
@@ -51,7 +51,7 @@ imports:
 - name: github.com/codahale/chacha20poly1305
   version: f8a5c48301822c3d7dd26d78e68ea2968db0ab20
 - name: github.com/davecgh/go-spew
-  version: 6cf5744a041a0022271cefed95ba843f6d87fd51
+  version: 6d212800a42e8ab5c146b8ace3490ee17e5225f9
   subpackages:
   - spew
 - name: github.com/golang/protobuf
@@ -82,7 +82,7 @@ imports:
   - txsort
   - base58
 - name: github.com/roasbeef/btcwallet
-  version: d7d402cc4135a53230ce068dcc51252c58a11a3d
+  version: 1fd2d6224698e14591d06f2a10b24e86494cc19f
   subpackages:
   - chain
   - waddrmgr
@@ -102,7 +102,7 @@ imports:
 - name: github.com/urfave/cli
   version: a14d7d367bc02b1f57d88de97926727f2d936387
 - name: golang.org/x/crypto
-  version: f160b6bf95857cd862817875dd958be022e587c4
+  version: 9e590154d2353f3f5e1b24da7275686040dcf491
   subpackages:
   - hkdf
   - nacl/secretbox
@@ -113,7 +113,7 @@ imports:
   - pbkdf2
   - ssh/terminal
 - name: golang.org/x/net
-  version: 1358eff22f0dd0c54fc521042cc607f6ff4b531a
+  version: 9313baa13d9262e49d07b20ed57dceafcd7240cc
   subpackages:
   - context
   - http2
@@ -122,7 +122,7 @@ imports:
   - lex/httplex
   - internal/timeseries
 - name: golang.org/x/sys
-  version: a646d33e2ee3172a661fc09bca23bb4889a41bc8
+  version: 30de6d19a3bd89a5f38ae4028e23aaa5582648af
   subpackages:
   - unix
 - name: google.golang.org/grpc

glide.yaml

@@ -37,6 +37,7 @@ import:
   - hdkeychain
   - txsort
 - package: github.com/roasbeef/btcwallet
+  version: master
   subpackages:
   - chain
   - waddrmgr

lnd.go

@@ -18,6 +18,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
 	"github.com/roasbeef/btcrpcclient"
 )
 
@@ -116,9 +117,8 @@ func lndMain() error {
 		return err
 	}
 
-	// Create, and start the lnwallet, which handles the core payment
-	// channel logic, and exposes control via proxy state machines.
-	walletConfig := &lnwallet.Config{
+	// TODO(roasbeef): paarse config here select chosen WalletController
+	walletConfig := &btcwallet.Config{
 		PrivatePass: []byte("hello"),
 		DataDir:     filepath.Join(loadedConfig.DataDir, "lnwallet"),
 		RpcHost:     fmt.Sprintf("%v:%v", rpcIP[0], activeNetParams.rpcPort),
@@ -127,7 +127,18 @@ func lndMain() error {
 		CACert:      rpcCert,
 		NetParams:   activeNetParams.Params,
 	}
-	wallet, err := lnwallet.NewLightningWallet(walletConfig, chanDB, notifier)
+	wc, err := btcwallet.New(walletConfig)
+	if err != nil {
+		fmt.Printf("unable to create wallet controller: %v\n", err)
+		return err
+	}
+	signer := wc
+	bio := wc
+
+	// Create, and start the lnwallet, which handles the core payment
+	// channel logic, and exposes control via proxy state machines.
+	wallet, err := lnwallet.NewLightningWallet(chanDB, notifier,
+		wc, signer, bio, activeNetParams.Params)
 	if err != nil {
 		fmt.Printf("unable to create wallet: %v\n", err)
 		return err
@@ -138,9 +149,6 @@ func lndMain() error {
 	}
 	ltndLog.Info("LightningWallet opened")
 
-	ec := &lnwallet.WaddrmgrEncryptorDecryptor{wallet.Manager}
-	chanDB.RegisterCryptoSystem(ec)
-
 	// Set up the core server which will listen for incoming peer
 	// connections.
 	defaultListenAddrs := []string{

lnwallet/btcwallet/blockchain.go

@@ -0,0 +1,55 @@
+package btcwallet
+
+import (
+	"encoding/hex"
+
+	"github.com/roasbeef/btcd/wire"
+)
+
+// GetCurrentHeight returns the current height of the known block within the
+// main chain.
+//
+// This method is a part of the lnwallet.BlockChainIO interface.
+func (b *BtcWallet) GetCurrentHeight() (int32, error) {
+	_, height, err := b.rpc.GetBestBlock()
+	if err != nil {
+		return 0, err
+	}
+
+	return height, nil
+}
+
+// GetTxOut returns the original output referenced by the passed outpoint.
+//
+// This method is a part of the lnwallet.BlockChainIO interface.
+func (b *BtcWallet) GetUtxo(txid *wire.ShaHash, index uint32) (*wire.TxOut, error) {
+	txout, err := b.rpc.GetTxOut(txid, index, false)
+	if err != nil {
+		return nil, err
+	}
+
+	pkScript, err := hex.DecodeString(txout.ScriptPubKey.Hex)
+	if err != nil {
+		return nil, err
+	}
+
+	return &wire.TxOut{
+		// Sadly, gettxout returns the output value in BTC
+		// instead of satoshis.
+		Value:    int64(txout.Value) * 1e8,
+		PkScript: pkScript,
+	}, nil
+}
+
+// GetTransaction returns the full transaction identified by the passed
+// transaction ID.
+//
+// This method is a part of the lnwallet.BlockChainIO interface.
+func (b *BtcWallet) GetTransaction(txid *wire.ShaHash) (*wire.MsgTx, error) {
+	tx, err := b.rpc.GetRawTransaction(txid)
+	if err != nil {
+		return nil, err
+	}
+
+	return tx.MsgTx(), nil
+}

lnwallet/btcwallet/btcwallet.go

@@ -0,0 +1,380 @@
+package btcwallet
+
+import (
+	"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)
+}

lnwallet/btcwallet/config.go

@@ -0,0 +1,94 @@
+package btcwallet
+
+import (
+	"path/filepath"
+
+	"github.com/roasbeef/btcd/chaincfg"
+	"github.com/roasbeef/btcd/wire"
+	"github.com/roasbeef/btcutil"
+	_ "github.com/roasbeef/btcwallet/walletdb/bdb"
+)
+
+var (
+	lnwalletHomeDir = btcutil.AppDataDir("lnwallet", false)
+	defaultDataDir  = lnwalletHomeDir
+
+	defaultLogFilename = "lnwallet.log"
+	defaultLogDirname  = "logs"
+	defaultLogDir      = filepath.Join(lnwalletHomeDir, defaultLogDirname)
+
+	btcdHomeDir        = btcutil.AppDataDir("btcd", false)
+	btcdHomedirCAFile  = filepath.Join(btcdHomeDir, "rpc.cert")
+	defaultRPCKeyFile  = filepath.Join(lnwalletHomeDir, "rpc.key")
+	defaultRPCCertFile = filepath.Join(lnwalletHomeDir, "rpc.cert")
+
+	// defaultPubPassphrase is the default public wallet passphrase which is
+	// used when the user indicates they do not want additional protection
+	// provided by having all public data in the wallet encrypted by a
+	// passphrase only known to them.
+	defaultPubPassphrase = []byte("public")
+
+	walletDbName = "lnwallet.db"
+)
+
+// Config is a struct which houses configuration paramters which modify the
+// instance of BtcWallet generated by the New() function.
+type Config struct {
+	// DataDir is the name of the directory where the wallet's persistent
+	// state should be sotred.
+	DataDir string
+
+	// LogDir is the name of the directory which should be used to store
+	// generated log files.
+	LogDir string
+
+	// DebugLevel is a string representing the level of verbosity the
+	// logger should use.
+	DebugLevel string
+
+	// RpcHost is the host and port to use to reach the rpc sever.
+	RpcHost string // localhost:18334
+
+	// RpcUser is the username which should be used to authentiate with the
+	// rpc server.
+	RpcUser string
+
+	// RpcPass is the password which should be used to authenticate the
+	// connection with the RPC server.
+	RpcPass string
+
+	// RpcNoTLS denotes if a TLS connection should be attempted when
+	// connecting to the RPC server.
+	RpcNoTLS bool
+
+	// RPCCert directory where the TLS certificate of the RPC sever is
+	// stored. If the RpcNoTLS is false, then this value will be unused.
+	RPCCert string
+	RPCKey  string
+
+	// CACert is the raw RPC cert for btcd.
+	CACert []byte
+
+	PrivatePass []byte
+	PublicPass  []byte
+	HdSeed      []byte
+
+	NetParams *chaincfg.Params
+}
+
+// networkDir returns the directory name of a network directory to hold wallet
+// files.
+func networkDir(dataDir string, chainParams *chaincfg.Params) string {
+	netname := chainParams.Name
+
+	// For now, we must always name the testnet data directory as "testnet"
+	// and not "testnet3" or any other version, as the chaincfg testnet3
+	// paramaters will likely be switched to being named "testnet3" in the
+	// future.  This is done to future proof that change, and an upgrade
+	// plan to move the testnet3 data directory can be worked out later.
+	if chainParams.Net == wire.TestNet3 {
+		netname = "testnet"
+	}
+
+	return filepath.Join(dataDir, netname)
+}

lnwallet/btcwallet/driver.go

@@ -0,0 +1,45 @@
+package btcwallet
+
+import (
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/lnwallet"
+)
+
+const (
+	walletType = "btcwallet"
+)
+
+// createNewWallet creates a new instance of BtcWallet given the proper list of
+// initialization parameters. This function is the factory function required to
+// properly create an instance of the lnwallet.WalletDriver struct for
+// BtcWallet.
+func createNewWallet(args ...interface{}) (lnwallet.WalletController, error) {
+	if len(args) != 1 {
+		return nil, fmt.Errorf("incorrect number of arguments to .New(...), "+
+			"expected 1, instead passed %v", len(args))
+	}
+
+	config, ok := args[0].(*Config)
+	if !ok {
+		return nil, fmt.Errorf("first argument to btcdnotifier.New is " +
+			"incorrect, expected a *btcrpcclient.ConnConfig")
+	}
+
+	return New(config)
+}
+
+// init registers a driver for the BtcWallet concrete implementation of the
+// lnwallet.WalletController interface.
+func init() {
+	// Register the driver.
+	driver := &lnwallet.WalletDriver{
+		WalletType: walletType,
+		New:        createNewWallet,
+	}
+
+	if err := lnwallet.RegisterWallet(driver); err != nil {
+		panic(fmt.Sprintf("failed to register wallet driver '%s': %v",
+			walletType, err))
+	}
+}

lnwallet/btcwallet/signer.go

@@ -0,0 +1,174 @@
+package btcwallet
+
+import (
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/roasbeef/btcd/txscript"
+	"github.com/roasbeef/btcd/wire"
+	"github.com/roasbeef/btcutil"
+	"github.com/roasbeef/btcwallet/waddrmgr"
+)
+
+// 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.
+//
+// This is a part of the WalletController interface.
+func (b *BtcWallet) FetchInputInfo(prevOut *wire.OutPoint) (*wire.TxOut, error) {
+	var (
+		err    error
+		output *wire.TxOut
+	)
+
+	// First check to see if the output is already within the utxo cache.
+	// If so we can return directly saving usk a disk access.
+	b.cacheMtx.RLock()
+	if output, ok := b.utxoCache[*prevOut]; ok {
+		b.cacheMtx.RUnlock()
+		return output, nil
+	}
+	b.cacheMtx.RUnlock()
+
+	// Otherwse, we manually look up the output within the tx store.
+	txDetail, err := b.wallet.TxStore.TxDetails(&prevOut.Hash)
+	if err != nil {
+		return nil, err
+	} else if txDetail == nil {
+		return nil, lnwallet.ErrNotMine
+	}
+
+	output = txDetail.TxRecord.MsgTx.TxOut[prevOut.Index]
+
+	b.cacheMtx.Lock()
+	b.utxoCache[*prevOut] = output
+	b.cacheMtx.Unlock()
+
+	return output, nil
+}
+
+// fetchOutputKey attempts to fetch the managed address corresponding to the
+// passed output script. This function is used to look up the proper key which
+// should be used to sign a specified input.
+func (b *BtcWallet) fetchOutputAddr(script []byte) (waddrmgr.ManagedAddress, error) {
+	_, addrs, _, err := txscript.ExtractPkScriptAddrs(script, b.netParams)
+	if err != nil {
+		return nil, err
+	}
+
+	// If the case of a multi-sig output, several address may be extracted.
+	// Therefore, we simply select the key for the first address we know
+	// of.
+	for _, addr := range addrs {
+		wAddr, err := b.wallet.Manager.Address(addr)
+		if err == nil {
+			return wAddr, nil
+		}
+	}
+
+	// TODO(roasbeef): use the errors.wrap package
+	return nil, fmt.Errorf("address not found")
+}
+
+// SignOutputRaw generates a signature for the passed transaction according to
+// the data within the passed SignDescriptor.
+//
+// This is a part of the WalletController interface.
+func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx, signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+	redeemScript := signDesc.RedeemScript
+	walletAddr, err := b.fetchOutputAddr(redeemScript)
+	if err != nil {
+		return nil, err
+	}
+
+	privKey, err := walletAddr.(waddrmgr.ManagedPubKeyAddress).PrivKey()
+	if err != nil {
+		return nil, err
+	}
+
+	amt := signDesc.Output.Value
+	sig, err := txscript.RawTxInWitnessSignature(tx, signDesc.SigHashes, 0,
+		amt, redeemScript, txscript.SigHashAll, privKey)
+	if err != nil {
+		return nil, err
+	}
+
+	// Chop off the sighash flag at the end of the signature.
+	return sig[:len(sig)-1], nil
+}
+
+// ComputeInputScript generates a complete InputIndex for the passed
+// transaction with the signature as defined within the passed SignDescriptor.
+// This method is capable of generating the proper input script for both
+// regular p2wkh output and p2wkh outputs nested within a regualr p2sh output.
+//
+// This is a part of the WalletController interface.
+func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
+	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+
+	outputScript := signDesc.Output.PkScript
+	walletAddr, err := b.fetchOutputAddr(outputScript)
+	if err != nil {
+		return nil, nil
+	}
+
+	pka := walletAddr.(waddrmgr.ManagedPubKeyAddress)
+	privKey, err := pka.PrivKey()
+	if err != nil {
+		return nil, err
+	}
+
+	var witnessProgram []byte
+	inputScript := &lnwallet.InputScript{}
+
+	// If we're spending p2wkh output nested within a p2sh output, then
+	// we'll need to attach a sigScript in addition to witness data.
+	switch {
+	case pka.IsNestedWitness():
+		pubKey := privKey.PubKey()
+		pubKeyHash := btcutil.Hash160(pubKey.SerializeCompressed())
+
+		// Next, we'll generate a valid sigScript that'll allow us to
+		// spend the p2sh output. The sigScript will contain only a
+		// single push of the p2wkh witness program corresponding to
+		// the matching public key of this address.
+		p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(pubKeyHash,
+			b.netParams)
+		if err != nil {
+			return nil, err
+		}
+		witnessProgram, err = txscript.PayToAddrScript(p2wkhAddr)
+		if err != nil {
+			return nil, err
+		}
+
+		bldr := txscript.NewScriptBuilder()
+		bldr.AddData(witnessProgram)
+		sigScript, err := bldr.Script()
+		if err != nil {
+			return nil, err
+		}
+
+		inputScript.ScriptSig = sigScript
+	// Otherwise, this is a regular p2wkh output, so we include the
+	// witness program itself as the subscript to generate the proper
+	// sighash digest. As part of the new sighash digest algorithm, the
+	// p2wkh witness program will be expanded into a regular p2kh
+	// script.
+	default:
+		witnessProgram = outputScript
+	}
+
+	// Generate a valid witness stack for the input.
+	witnessScript, err := txscript.WitnessScript(tx, signDesc.SigHashes,
+		signDesc.InputIndex, signDesc.Output.Value, witnessProgram,
+		txscript.SigHashAll, privKey, true)
+	if err != nil {
+		return nil, err
+	}
+
+	inputScript.Witness = witnessScript
+
+	return inputScript, nil
+}

lnwallet/channel.go

@@ -274,6 +274,9 @@ type LightningChannel struct {
 	// wallet can add back.
 	lnwallet *LightningWallet
 
+	signer   Signer
+	signDesc *SignDescriptor
+
 	channelEvents chainntnfs.ChainNotifier
 
 	sync.RWMutex
@@ -281,7 +284,8 @@ type LightningChannel struct {
 	ourLogCounter   uint32
 	theirLogCounter uint32
 
-	status channelState
+	status   channelState
+	Capacity btcutil.Amount
 
 	// currentHeight is the current height of our local commitment chain.
 	// This is also the same as the number of updates to the channel we've
@@ -337,10 +341,12 @@ type LightningChannel struct {
 	ourLogIndex   map[uint32]*list.Element
 	theirLogIndex map[uint32]*list.Element
 
-	fundingTxIn  *wire.TxIn
-	fundingP2WSH []byte
+	LocalDeliveryScript  []byte
+	RemoteDeliveryScript []byte
 
-	channelDB *channeldb.DB
+	FundingRedeemScript []byte
+	fundingTxIn         *wire.TxIn
+	fundingP2WSH        []byte
 
 	started  int32
 	shutdown int32
@@ -354,11 +360,13 @@ type LightningChannel struct {
 // and the current settled channel state. Throughout state transitions, then
 // channel will automatically persist pertinent state to the database in an
 // efficient manner.
-func NewLightningChannel(wallet *LightningWallet, events chainntnfs.ChainNotifier,
-	chanDB *channeldb.DB, state *channeldb.OpenChannel) (*LightningChannel, error) {
+func NewLightningChannel(signer Signer, wallet *LightningWallet,
+	events chainntnfs.ChainNotifier,
+	state *channeldb.OpenChannel) (*LightningChannel, error) {
 
 	// TODO(roasbeef): remove events+wallet
 	lc := &LightningChannel{
+		signer:               signer,
 		lnwallet:             wallet,
 		channelEvents:        events,
 		currentHeight:        state.NumUpdates,
@@ -370,7 +378,10 @@ func NewLightningChannel(wallet *LightningWallet, events chainntnfs.ChainNotifie
 		theirUpdateLog:       list.New(),
 		ourLogIndex:          make(map[uint32]*list.Element),
 		theirLogIndex:        make(map[uint32]*list.Element),
-		channelDB:            chanDB,
+		Capacity:             state.Capacity,
+		LocalDeliveryScript:  state.OurDeliveryScript,
+		RemoteDeliveryScript: state.TheirDeliveryScript,
+		FundingRedeemScript:  state.FundingRedeemScript,
 	}
 
 	// Initialize both of our chains the current un-revoked commitment for
@@ -395,6 +406,17 @@ func NewLightningChannel(wallet *LightningWallet, events chainntnfs.ChainNotifie
 	lc.fundingTxIn = wire.NewTxIn(state.FundingOutpoint, nil, nil)
 	lc.fundingP2WSH = fundingPkScript
 
+	lc.signDesc = &SignDescriptor{
+		PubKey:       lc.channelState.OurMultiSigKey,
+		RedeemScript: lc.channelState.FundingRedeemScript,
+		Output: &wire.TxOut{
+			PkScript: lc.fundingP2WSH,
+			Value:    int64(lc.channelState.Capacity),
+		},
+		HashType:   txscript.SigHashAll,
+		InputIndex: 0,
+	}
+
 	return lc, nil
 }
 
@@ -480,12 +502,12 @@ func (lc *LightningChannel) fetchCommitmentView(remoteChain bool,
 	var delayBalance, p2wkhBalance btcutil.Amount
 	if remoteChain {
 		selfKey = lc.channelState.TheirCommitKey
-		remoteKey = lc.channelState.OurCommitKey.PubKey()
+		remoteKey = lc.channelState.OurCommitKey
 		delay = lc.channelState.RemoteCsvDelay
 		delayBalance = theirBalance
 		p2wkhBalance = ourBalance
 	} else {
-		selfKey = lc.channelState.OurCommitKey.PubKey()
+		selfKey = lc.channelState.OurCommitKey
 		remoteKey = lc.channelState.TheirCommitKey
 		delay = lc.channelState.LocalCsvDelay
 		delayBalance = ourBalance
@@ -495,7 +517,7 @@ func (lc *LightningChannel) fetchCommitmentView(remoteChain bool,
 	// Generate a new commitment transaction with all the latest
 	// unsettled/un-timed out HTLC's.
 	ourCommitTx := !remoteChain
-	commitTx, err := createCommitTx(lc.fundingTxIn, selfKey, remoteKey,
+	commitTx, err := CreateCommitTx(lc.fundingTxIn, selfKey, remoteKey,
 		revocationKey, delay, delayBalance, p2wkhBalance)
 	if err != nil {
 		return nil, err
@@ -722,11 +744,8 @@ func (lc *LightningChannel) SignNextCommitment() ([]byte, uint32, error) {
 		}))
 
 	// Sign their version of the new commitment transaction.
-	hashCache := txscript.NewTxSigHashes(newCommitView.txn)
-	sig, err := txscript.RawTxInWitnessSignature(newCommitView.txn,
-		hashCache, 0, int64(lc.channelState.Capacity),
-		lc.channelState.FundingRedeemScript, txscript.SigHashAll,
-		lc.channelState.OurMultiSigKey)
+	lc.signDesc.SigHashes = txscript.NewTxSigHashes(newCommitView.txn)
+	sig, err := lc.signer.SignOutputRaw(newCommitView.txn, lc.signDesc)
 	if err != nil {
 		return nil, 0, err
 	}
@@ -744,7 +763,7 @@ func (lc *LightningChannel) SignNextCommitment() ([]byte, uint32, error) {
 
 	// Strip off the sighash flag on the signature in order to send it over
 	// the wire.
-	return sig[:len(sig)], lc.theirLogCounter, nil
+	return sig, lc.theirLogCounter, nil
 }
 
 // ReceiveNewCommitment processs a signature for a new commitment state sent by
@@ -770,7 +789,7 @@ func (lc *LightningChannel) ReceiveNewCommitment(rawSig []byte,
 	if err != nil {
 		return err
 	}
-	revocationKey := deriveRevocationPubkey(theirCommitKey, revocation[:])
+	revocationKey := DeriveRevocationPubkey(theirCommitKey, revocation[:])
 	revocationHash := fastsha256.Sum256(revocation[:])
 
 	// With the revocation information calculated, construct the new
@@ -857,7 +876,7 @@ func (lc *LightningChannel) RevokeCurrentCommitment() (*lnwire.CommitRevocation,
 	if err != nil {
 		return nil, err
 	}
-	revocationMsg.NextRevocationKey = deriveRevocationPubkey(theirCommitKey,
+	revocationMsg.NextRevocationKey = DeriveRevocationPubkey(theirCommitKey,
 		revocationEdge[:])
 	revocationMsg.NextRevocationHash = fastsha256.Sum256(revocationEdge[:])
 
@@ -921,8 +940,8 @@ func (lc *LightningChannel) ReceiveRevocation(revMsg *lnwire.CommitRevocation) (
 	// Verify that the revocation public key we can derive using this
 	// pre-image and our private key is identical to the revocation key we
 	// were given for their current (prior) commitment transaction.
-	revocationPriv := deriveRevocationPrivKey(ourCommitKey, pendingRevocation[:])
-	if !revocationPriv.PubKey().IsEqual(currentRevocationKey) {
+	revocationPub := DeriveRevocationPubkey(ourCommitKey, pendingRevocation[:])
+	if !revocationPub.IsEqual(currentRevocationKey) {
 		return nil, fmt.Errorf("revocation key mismatch")
 	}
 
@@ -1067,7 +1086,7 @@ func (lc *LightningChannel) ExtendRevocationWindow() (*lnwire.CommitRevocation,
 	}
 
 	theirCommitKey := lc.channelState.TheirCommitKey
-	revMsg.NextRevocationKey = deriveRevocationPubkey(theirCommitKey,
+	revMsg.NextRevocationKey = DeriveRevocationPubkey(theirCommitKey,
 		revocation[:])
 	revMsg.NextRevocationHash = fastsha256.Sum256(revocation[:])
 
@@ -1201,7 +1220,7 @@ func (lc *LightningChannel) addHTLC(commitTx *wire.MsgTx, ourCommit bool,
 	paymentDesc *PaymentDescriptor, revocation [32]byte, delay uint32,
 	isIncoming bool) error {
 
-	localKey := lc.channelState.OurCommitKey.PubKey()
+	localKey := lc.channelState.OurCommitKey
 	remoteKey := lc.channelState.TheirCommitKey
 	timeout := paymentDesc.Timeout
 	rHash := paymentDesc.RHash
@@ -1288,7 +1307,7 @@ func (lc *LightningChannel) InitCooperativeClose() ([]byte, *wire.ShaHash, error
 	lc.status = channelClosing
 
 	// TODO(roasbeef): assumes initiator pays fees
-	closeTx := createCooperativeCloseTx(lc.fundingTxIn,
+	closeTx := CreateCooperativeCloseTx(lc.fundingTxIn,
 		lc.channelState.OurBalance, lc.channelState.TheirBalance,
 		lc.channelState.OurDeliveryScript, lc.channelState.TheirDeliveryScript,
 		true)
@@ -1298,11 +1317,8 @@ func (lc *LightningChannel) InitCooperativeClose() ([]byte, *wire.ShaHash, error
 	// initiator we'll simply send our signature over the the remote party,
 	// using the generated txid to be notified once the closure transaction
 	// has been confirmed.
-	hashCache := txscript.NewTxSigHashes(closeTx)
-	closeSig, err := txscript.RawTxInWitnessSignature(closeTx,
-		hashCache, 0, int64(lc.channelState.Capacity),
-		lc.channelState.FundingRedeemScript, txscript.SigHashAll,
-		lc.channelState.OurMultiSigKey)
+	lc.signDesc.SigHashes = txscript.NewTxSigHashes(closeTx)
+	closeSig, err := lc.signer.SignOutputRaw(closeTx, lc.signDesc)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -1315,6 +1331,9 @@ func (lc *LightningChannel) InitCooperativeClose() ([]byte, *wire.ShaHash, error
 // remote node initating a cooperative channel closure. A fully signed closure
 // transaction is returned. It is the duty of the responding node to broadcast
 // a signed+valid closure transaction to the network.
+//
+// NOTE: The passed remote sig is expected to the a fully complete signature
+// including the proper sighash byte.
 func (lc *LightningChannel) CompleteCooperativeClose(remoteSig []byte) (*wire.MsgTx, error) {
 	lc.Lock()
 	defer lc.Unlock()
@@ -1330,35 +1349,34 @@ func (lc *LightningChannel) CompleteCooperativeClose(remoteSig []byte) (*wire.Ms
 	// Create the transaction used to return the current settled balance
 	// on this active channel back to both parties. In this current model,
 	// the initiator pays full fees for the cooperative close transaction.
-	closeTx := createCooperativeCloseTx(lc.fundingTxIn,
+	closeTx := CreateCooperativeCloseTx(lc.fundingTxIn,
 		lc.channelState.OurBalance, lc.channelState.TheirBalance,
 		lc.channelState.OurDeliveryScript, lc.channelState.TheirDeliveryScript,
 		false)
 
 	// With the transaction created, we can finally generate our half of
 	// the 2-of-2 multi-sig needed to redeem the funding output.
-	redeemScript := lc.channelState.FundingRedeemScript
 	hashCache := txscript.NewTxSigHashes(closeTx)
-	capacity := int64(lc.channelState.Capacity)
-	closeSig, err := txscript.RawTxInWitnessSignature(closeTx,
-		hashCache, 0, capacity, redeemScript, txscript.SigHashAll,
-		lc.channelState.OurMultiSigKey)
+	lc.signDesc.SigHashes = hashCache
+	closeSig, err := lc.signer.SignOutputRaw(closeTx, lc.signDesc)
 	if err != nil {
 		return nil, err
 	}
 
 	// Finally, construct the witness stack minding the order of the
 	// pubkeys+sigs on the stack.
-	ourKey := lc.channelState.OurMultiSigKey.PubKey().SerializeCompressed()
+	ourKey := lc.channelState.OurMultiSigKey.SerializeCompressed()
 	theirKey := lc.channelState.TheirMultiSigKey.SerializeCompressed()
-	witness := spendMultiSig(redeemScript, ourKey, closeSig,
+	ourSig := append(closeSig, byte(txscript.SigHashAll))
+	witness := SpendMultiSig(lc.signDesc.RedeemScript, ourKey, ourSig,
 		theirKey, remoteSig)
 	closeTx.TxIn[0].Witness = witness
 
 	// Validate the finalized transaction to ensure the output script is
 	// properly met, and that the remote peer supplied a valid signature.
 	vm, err := txscript.NewEngine(lc.fundingP2WSH, closeTx, 0,
-		txscript.StandardVerifyFlags, nil, hashCache, capacity)
+		txscript.StandardVerifyFlags, nil, hashCache,
+		int64(lc.channelState.Capacity))
 	if err != nil {
 		return nil, err
 	}
@@ -1376,7 +1394,8 @@ func (lc *LightningChannel) DeleteState() error {
 	return lc.channelState.CloseChannel()
 }
 
-// StateSnapshot returns a snapshot b
+// StateSnapshot returns a snapshot of the current fully committed state within
+// the channel.
 func (lc *LightningChannel) StateSnapshot() *channeldb.ChannelSnapshot {
 	lc.stateMtx.RLock()
 	defer lc.stateMtx.RUnlock()
@@ -1384,12 +1403,12 @@ func (lc *LightningChannel) StateSnapshot() *channeldb.ChannelSnapshot {
 	return lc.channelState.Snapshot()
 }
 
-// createCommitTx creates a commitment transaction, spending from specified
+// CreateCommitTx creates a commitment transaction, spending from specified
 // funding output. The commitment transaction contains two outputs: one paying
 // to the "owner" of the commitment transaction which can be spent after a
 // relative block delay or revocation event, and the other paying the the
 // counter-party within the channel, which can be spent immediately.
-func createCommitTx(fundingOutput *wire.TxIn, selfKey, theirKey *btcec.PublicKey,
+func CreateCommitTx(fundingOutput *wire.TxIn, selfKey, theirKey *btcec.PublicKey,
 	revokeKey *btcec.PublicKey, csvTimeout uint32, amountToSelf,
 	amountToThem btcutil.Amount) (*wire.MsgTx, error) {
 
@@ -1433,13 +1452,13 @@ func createCommitTx(fundingOutput *wire.TxIn, selfKey, theirKey *btcec.PublicKey
 	return commitTx, nil
 }
 
-// createCooperativeCloseTx creates a transaction which if signed by both
+// CreateCooperativeCloseTx creates a transaction which if signed by both
 // parties, then broadcast cooperatively closes an active channel. The creation
 // of the closure transaction is modified by a boolean indicating if the party
 // constructing the channel is the initiator of the closure. Currently it is
 // expected that the initiator pays the transaction fees for the closing
 // transaction in full.
-func createCooperativeCloseTx(fundingTxIn *wire.TxIn,
+func CreateCooperativeCloseTx(fundingTxIn *wire.TxIn,
 	ourBalance, theirBalance btcutil.Amount,
 	ourDeliveryScript, theirDeliveryScript []byte,
 	initiator bool) *wire.MsgTx {

lnwallet/channel_test.go

@@ -13,27 +13,64 @@ import (
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/chaincfg"
+	"github.com/roasbeef/btcd/txscript"
 	"github.com/roasbeef/btcd/wire"
 	"github.com/roasbeef/btcutil"
 )
 
-// MockEncryptorDecryptor is a mock implementation of EncryptorDecryptor that
-// simply returns the passed bytes without encrypting or decrypting. This is
-// used for testing purposes to be able to create a channldb instance which
-// doesn't use encryption.
-type MockEncryptorDecryptor struct {
+var (
+	privPass = []byte("private-test")
+
+	// For simplicity a single priv key controls all of our test outputs.
+	testWalletPrivKey = []byte{
+		0x2b, 0xd8, 0x06, 0xc9, 0x7f, 0x0e, 0x00, 0xaf,
+		0x1a, 0x1f, 0xc3, 0x32, 0x8f, 0xa7, 0x63, 0xa9,
+		0x26, 0x97, 0x23, 0xc8, 0xdb, 0x8f, 0xac, 0x4f,
+		0x93, 0xaf, 0x71, 0xdb, 0x18, 0x6d, 0x6e, 0x90,
+	}
+
+	// We're alice :)
+	bobsPrivKey = []byte{
+		0x81, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
+		0x63, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
+		0xd, 0xe7, 0x95, 0xe4, 0xb7, 0x25, 0xb8, 0x4d,
+		0x1e, 0xb, 0x4c, 0xfd, 0x9e, 0xc5, 0x8c, 0xe9,
+	}
+
+	// Use a hard-coded HD seed.
+	testHdSeed = [32]byte{
+		0xb7, 0x94, 0x38, 0x5f, 0x2d, 0x1e, 0xf7, 0xab,
+		0x4d, 0x92, 0x73, 0xd1, 0x90, 0x63, 0x81, 0xb4,
+		0x4f, 0x2f, 0x6f, 0x25, 0x88, 0xa3, 0xef, 0xb9,
+		0x6a, 0x49, 0x18, 0x83, 0x31, 0x98, 0x47, 0x53,
+	}
+
+	// The number of confirmations required to consider any created channel
+	// open.
+	numReqConfs = uint16(1)
+)
+
+type mockSigner struct {
+	key *btcec.PrivateKey
 }
 
-func (m *MockEncryptorDecryptor) Encrypt(n []byte) ([]byte, error) {
-	return n, nil
+func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *SignDescriptor) ([]byte, error) {
+	amt := signDesc.Output.Value
+	redeemScript := signDesc.RedeemScript
+	privKey := m.key
+
+	sig, err := txscript.RawTxInWitnessSignature(tx, signDesc.SigHashes,
+		signDesc.InputIndex, amt, redeemScript, txscript.SigHashAll, privKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return sig[:len(sig)-1], nil
 }
 
-func (m *MockEncryptorDecryptor) Decrypt(n []byte) ([]byte, error) {
-	return n, nil
-}
-
-func (m *MockEncryptorDecryptor) OverheadSize() uint32 {
-	return 0
+// ComputeInputScript...
+func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*InputScript, error) {
+	return nil, nil
 }
 
 // createTestChannels creates two test channels funded with 10 BTC, with 5 BTC
@@ -49,7 +86,7 @@ func createTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	csvTimeoutAlice := uint32(5)
 	csvTimeoutBob := uint32(4)
 
-	redeemScript, _, err := genFundingPkScript(aliceKeyPub.SerializeCompressed(),
+	redeemScript, _, err := GenFundingPkScript(aliceKeyPub.SerializeCompressed(),
 		bobKeyPub.SerializeCompressed(), int64(channelCapacity))
 	if err != nil {
 		return nil, nil, nil, err
@@ -61,26 +98,26 @@ func createTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	}
 	fundingTxIn := wire.NewTxIn(prevOut, nil, nil)
 
-	bobElkrem := elkrem.NewElkremSender(deriveElkremRoot(bobKeyPriv, aliceKeyPub))
+	bobElkrem := elkrem.NewElkremSender(deriveElkremRoot(bobKeyPriv, bobKeyPub, aliceKeyPub))
 	bobFirstRevoke, err := bobElkrem.AtIndex(0)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	bobRevokeKey := deriveRevocationPubkey(aliceKeyPub, bobFirstRevoke[:])
+	bobRevokeKey := DeriveRevocationPubkey(aliceKeyPub, bobFirstRevoke[:])
 
-	aliceElkrem := elkrem.NewElkremSender(deriveElkremRoot(aliceKeyPriv, bobKeyPub))
+	aliceElkrem := elkrem.NewElkremSender(deriveElkremRoot(aliceKeyPriv, aliceKeyPub, bobKeyPub))
 	aliceFirstRevoke, err := aliceElkrem.AtIndex(0)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	aliceRevokeKey := deriveRevocationPubkey(bobKeyPub, aliceFirstRevoke[:])
+	aliceRevokeKey := DeriveRevocationPubkey(bobKeyPub, aliceFirstRevoke[:])
 
-	aliceCommitTx, err := createCommitTx(fundingTxIn, aliceKeyPub,
+	aliceCommitTx, err := CreateCommitTx(fundingTxIn, aliceKeyPub,
 		bobKeyPub, aliceRevokeKey, csvTimeoutAlice, channelBal, channelBal)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	bobCommitTx, err := createCommitTx(fundingTxIn, bobKeyPub,
+	bobCommitTx, err := CreateCommitTx(fundingTxIn, bobKeyPub,
 		aliceKeyPub, bobRevokeKey, csvTimeoutBob, channelBal, channelBal)
 	if err != nil {
 		return nil, nil, nil, err
@@ -91,25 +128,24 @@ func createTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	dbAlice.RegisterCryptoSystem(&MockEncryptorDecryptor{})
+
 	bobPath, err := ioutil.TempDir("", "bobdb")
 	dbBob, err := channeldb.Open(bobPath, &chaincfg.TestNet3Params)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	dbBob.RegisterCryptoSystem(&MockEncryptorDecryptor{})
 
 	aliceChannelState := &channeldb.OpenChannel{
 		TheirLNID:              testHdSeed,
 		ChanID:                 prevOut,
-		OurCommitKey:           aliceKeyPriv,
+		OurCommitKey:           aliceKeyPub,
 		TheirCommitKey:         bobKeyPub,
 		Capacity:               channelCapacity,
 		OurBalance:             channelBal,
 		TheirBalance:           channelBal,
 		OurCommitTx:            aliceCommitTx,
 		FundingOutpoint:        prevOut,
-		OurMultiSigKey:         aliceKeyPriv,
+		OurMultiSigKey:         aliceKeyPub,
 		TheirMultiSigKey:       bobKeyPub,
 		FundingRedeemScript:    redeemScript,
 		LocalCsvDelay:          csvTimeoutAlice,
@@ -122,14 +158,14 @@ func createTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	bobChannelState := &channeldb.OpenChannel{
 		TheirLNID:              testHdSeed,
 		ChanID:                 prevOut,
-		OurCommitKey:           bobKeyPriv,
+		OurCommitKey:           bobKeyPub,
 		TheirCommitKey:         aliceKeyPub,
 		Capacity:               channelCapacity,
 		OurBalance:             channelBal,
 		TheirBalance:           channelBal,
 		OurCommitTx:            bobCommitTx,
 		FundingOutpoint:        prevOut,
-		OurMultiSigKey:         bobKeyPriv,
+		OurMultiSigKey:         bobKeyPub,
 		TheirMultiSigKey:       aliceKeyPub,
 		FundingRedeemScript:    redeemScript,
 		LocalCsvDelay:          csvTimeoutBob,
@@ -145,11 +181,14 @@ func createTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 		os.RemoveAll(alicePath)
 	}
 
-	channelAlice, err := NewLightningChannel(nil, nil, dbAlice, aliceChannelState)
+	aliceSigner := &mockSigner{aliceKeyPriv}
+	bobSigner := &mockSigner{bobKeyPriv}
+
+	channelAlice, err := NewLightningChannel(aliceSigner, nil, nil, aliceChannelState)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	channelBob, err := NewLightningChannel(nil, nil, dbBob, bobChannelState)
+	channelBob, err := NewLightningChannel(bobSigner, nil, nil, bobChannelState)
 	if err != nil {
 		return nil, nil, nil, err
 	}
@@ -456,7 +495,8 @@ func TestCooperativeChannelClosure(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unable to initiate alice cooperative close: %v", err)
 	}
-	closeTx, err := bobChannel.CompleteCooperativeClose(sig)
+	finalSig := append(sig, byte(txscript.SigHashAll))
+	closeTx, err := bobChannel.CompleteCooperativeClose(finalSig)
 	if err != nil {
 		t.Fatalf("unable to complete alice cooperative close: %v", err)
 	}
@@ -475,7 +515,8 @@ func TestCooperativeChannelClosure(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unable to initiate bob cooperative close: %v", err)
 	}
-	closeTx, err = aliceChannel.CompleteCooperativeClose(sig)
+	finalSig = append(sig, byte(txscript.SigHashAll))
+	closeTx, err = aliceChannel.CompleteCooperativeClose(finalSig)
 	if err != nil {
 		t.Fatalf("unable to complete bob cooperative close: %v", err)
 	}

lnwallet/coin_select.go

@@ -1,73 +0,0 @@
-package lnwallet
-
-import (
-	"encoding/hex"
-
-	"github.com/roasbeef/btcd/btcjson"
-	"github.com/roasbeef/btcd/wire"
-	"github.com/roasbeef/btcutil"
-	"github.com/roasbeef/btcutil/coinset"
-)
-
-// lnCoin represents a single unspet output. Its purpose is to convert a regular
-// output to a struct adhering to the coinset.Coin interface
-type lnCoin struct {
-	hash     *wire.ShaHash
-	index    uint32
-	value    btcutil.Amount
-	pkScript []byte
-	numConfs int64
-	valueAge int64
-}
-
-func (l *lnCoin) Hash() *wire.ShaHash   { return l.hash }
-func (l *lnCoin) Index() uint32         { return l.index }
-func (l *lnCoin) Value() btcutil.Amount { return l.value }
-func (l *lnCoin) PkScript() []byte      { return l.pkScript }
-func (l *lnCoin) NumConfs() int64       { return l.numConfs }
-func (l *lnCoin) ValueAge() int64       { return l.valueAge }
-
-// Ensure lnCoin adheres to the coinset.Coin interface.
-var _ coinset.Coin = (*lnCoin)(nil)
-
-// newLnCoin creates a new "coin" from the passed output. Coins are required
-// in order to perform coin selection upon.
-func newLnCoin(output *btcjson.ListUnspentResult) (coinset.Coin, error) {
-	txid, err := wire.NewShaHashFromStr(output.TxID)
-	if err != nil {
-		return nil, err
-	}
-
-	pkScript, err := hex.DecodeString(output.ScriptPubKey)
-	if err != nil {
-		return nil, err
-	}
-
-	return &lnCoin{
-		hash: txid,
-		// btcjson.ListUnspentResult shows the amount in BTC,
-		// translate into Satoshi so coin selection can work properly.
-		value:    btcutil.Amount(output.Amount * 1e8),
-		index:    output.Vout,
-		pkScript: pkScript,
-		numConfs: output.Confirmations,
-		// TODO(roasbeef): output.Amount should be a int64, damn json-RPC :/
-		valueAge: output.Confirmations * int64(output.Amount),
-	}, nil
-}
-
-// outputsToCoins converts a slice of transaction outputs to a coin-selectable
-// slice of "Coins"s.
-func outputsToCoins(outputs []*btcjson.ListUnspentResult) ([]coinset.Coin, error) {
-	coins := make([]coinset.Coin, len(outputs))
-	for i, output := range outputs {
-		coin, err := newLnCoin(output)
-		if err != nil {
-			return nil, err
-		}
-
-		coins[i] = coin
-	}
-
-	return coins, nil
-}

lnwallet/config.go

@@ -1,60 +1,15 @@
 package lnwallet
 
-import (
-	"path/filepath"
-
-	"github.com/roasbeef/btcd/chaincfg"
-	"github.com/roasbeef/btcutil"
-)
-
-var (
-	// TODO(roasbeef): lnwallet config file
-	lnwalletHomeDir = btcutil.AppDataDir("lnwallet", false)
-	defaultDataDir  = lnwalletHomeDir
-
-	defaultLogFilename = "lnwallet.log"
-	defaultLogDirname  = "logs"
-	defaultLogDir      = filepath.Join(lnwalletHomeDir, defaultLogDirname)
-
-	btcdHomeDir        = btcutil.AppDataDir("btcd", false)
-	btcdHomedirCAFile  = filepath.Join(btcdHomeDir, "rpc.cert")
-	defaultRPCKeyFile  = filepath.Join(lnwalletHomeDir, "rpc.key")
-	defaultRPCCertFile = filepath.Join(lnwalletHomeDir, "rpc.cert")
-
-	// defaultPubPassphrase is the default public wallet passphrase which is
-	// used when the user indicates they do not want additional protection
-	// provided by having all public data in the wallet encrypted by a
-	// passphrase only known to them.
-	defaultPubPassphrase = []byte("public")
-
-	walletDbName = "lnwallet.db"
-)
-
-// Config...
+// Config..
 type Config struct {
-	DataDir string
-	LogDir  string
-
-	DebugLevel string
-
-	RpcHost  string // localhost:18334
-	RpcUser  string
-	RpcPass  string
-	RpcNoTLS bool
-
-	RPCCert string
-	RPCKey  string
-
-	CACert []byte
-
-	PrivatePass []byte
-	PublicPass  []byte
-	HdSeed      []byte
-
-	// Which bitcoin network are we using?
-	NetParams *chaincfg.Params
-}
-
-// setDefaults...
-func setDefaults(confg *Config) {
+	// default csv time
+	// default cltv time
+	// default wait for funding time
+	// default wait for closure time
+	// min amount to accept channel
+	// min fee imformation
+	//  * or possibly interface to predict fees
+	// max htlcs in flight?
+	// possible secret derivation functions
+	//
 }

lnwallet/interface.go

@@ -1,11 +1,43 @@
 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
@@ -17,82 +49,71 @@ import (
 // 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) btcutil.Amount
+	ConfirmedBalance(confs int32, witness bool) (btcutil.Amount, error)
 
-	// NewAddress returns the next external address for the wallet. The
-	// type of address returned is dictated by the wallet's capabilities,
-	// and may be of type: p2sh, p2pkh, p2wkh, p2wsh, etc.
-	NewAddress(witness bool) (btcutil.Address, error)
-
-	// NewChangeAddress returns a new change address for the wallet. If the
-	// underlying wallet supports hd key chains, then this address should be
-	// dervied from an internal branch.
-	NewChangeAddress(witness bool) (btcutil.Address, 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.
-	GetPrivKey(a *btcutil.Address) (*btcec.PrivateKey, error)
+	// 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): key pool due to cancelled reservations??
-	NewRawKey() (*btcec.PrivateKey, error)
+	// TODO(roasbeef): may be scrapped, see above TODO
+	NewRawKey() (*btcec.PublicKey, error)
 
-	// FetchIdentityKey returns a private key which will be utilized as the
-	// wallet's Lightning Network identity for authentication purposes.
-	// TODO(roasbeef): rotate identity key?
-	FetchIdentityKey() (*btcec.PrivateKey, 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)
 
-	// FundTransaction creates a new unsigned transactions paying to the
-	// passed outputs, possibly using the specified change address. The
-	// includeFee parameter dictates if the wallet should also provide
-	// enough the funds necessary to create an adequate fee or not.
-	FundTransaction(outputs []*wire.TxOut, changeAddr btcutil.Address,
-		includeFee bool) (*wire.MsgTx, error)
-
-	// SignTransaction performs potentially a sparse, or full signing of
-	// all inputs within the passed transaction that are spendable by the
-	// wallet.
-	SignTransaction(tx *wire.MsgTx) error
-
-	// BroadcastTransaction performs cursory validation (dust checks, etc),
-	// then finally broadcasts the passed transaction to the Bitcoin network.
-	BroadcastTransaction(tx *wire.MsgTx) error
-
-	// SendMany 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.
-	SendMany(outputs []*wire.TxOut) (*wire.ShaHash, 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) ([]*wire.OutPoint, error)
+	// 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 eligble for coin selection. Locking outputs are utilized
-	// in order to avoid race conditions when selecting inputs for usage when
-	// funding a channel.
+	// 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)
 
-	// ImportScript imports the serialize public key script, or redeem
-	// script into the wallet's database. Scripts to be imported include
-	// the 2-of-2 script for funding transactions, commitment scripts,
-	// HTLCs scripts, and so on.
-	ImportScript(b []byte) error
+	// 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.
@@ -101,11 +122,147 @@ type WalletController interface {
 	// Stop signals the wallet for shutdown. Shutdown may entail closing
 	// any active sockets, database handles, stopping goroutines, etc.
 	Stop() error
-
-	// WaitForShutdown blocks until the wallet finishes the shutdown
-	// procedure triggered by a prior call to Stop().
-	WaitForShutdown() error
-
-	// TODO(roasbeef): ImportPriv?
-	//  * segwitty flag?
+}
+
+// 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
 }

lnwallet/interface_test.go

@@ -1,4 +1,4 @@
-package lnwallet
+package lnwallet_test
 
 import (
 	"bytes"
@@ -11,18 +11,20 @@ import (
 	"time"
 
 	"github.com/boltdb/bolt"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
 	"github.com/roasbeef/btcd/chaincfg"
 	"github.com/roasbeef/btcutil/txsort"
+	_ "github.com/roasbeef/btcwallet/walletdb/bdb"
 
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/rpctest"
 	"github.com/roasbeef/btcd/txscript"
 	"github.com/roasbeef/btcd/wire"
 	"github.com/roasbeef/btcutil"
-	"github.com/roasbeef/btcutil/coinset"
-	"github.com/roasbeef/btcwallet/waddrmgr"
 )
 
 var (
@@ -60,8 +62,8 @@ var (
 // assertProperBalance asserts than the total value of the unspent outputs
 // within the wallet are *exactly* amount. If unable to retrieve the current
 // balance, or the assertion fails, the test will halt with a fatal error.
-func assertProperBalance(t *testing.T, lw *LightningWallet, numConfirms int32, amount int64) {
-	balance, err := lw.CalculateBalance(numConfirms)
+func assertProperBalance(t *testing.T, lw *lnwallet.LightningWallet, numConfirms int32, amount int64) {
+	balance, err := lw.ConfirmedBalance(numConfirms, false)
 	if err != nil {
 		t.Fatalf("unable to query for balance: %v", err)
 	}
@@ -72,7 +74,7 @@ func assertProperBalance(t *testing.T, lw *LightningWallet, numConfirms int32, a
 }
 
 func assertChannelOpen(t *testing.T, miner *rpctest.Harness, numConfs uint32,
-	c <-chan *LightningChannel) *LightningChannel {
+	c <-chan *lnwallet.LightningChannel) *lnwallet.LightningChannel {
 	// Mine a single block. After this block is mined, the channel should
 	// be considered fully open.
 	if _, err := miner.Node.Generate(1); err != nil {
@@ -108,9 +110,9 @@ type bobNode struct {
 
 // Contribution returns bobNode's contribution necessary to open a payment
 // channel with Alice.
-func (b *bobNode) Contribution(aliceCommitKey *btcec.PublicKey) *ChannelContribution {
-	revokeKey := deriveRevocationPubkey(aliceCommitKey, b.revocation[:])
-	return &ChannelContribution{
+func (b *bobNode) Contribution(aliceCommitKey *btcec.PublicKey) *lnwallet.ChannelContribution {
+	revokeKey := lnwallet.DeriveRevocationPubkey(aliceCommitKey, b.revocation[:])
+	return &lnwallet.ChannelContribution{
 		FundingAmount:   b.fundingAmt,
 		Inputs:          b.availableOutputs,
 		ChangeOutputs:   b.changeOutputs,
@@ -124,9 +126,9 @@ func (b *bobNode) Contribution(aliceCommitKey *btcec.PublicKey) *ChannelContribu
 
 // SingleContribution returns bobNode's contribution to a single funded
 // channel. This contribution contains no inputs nor change outputs.
-func (b *bobNode) SingleContribution(aliceCommitKey *btcec.PublicKey) *ChannelContribution {
-	revokeKey := deriveRevocationPubkey(aliceCommitKey, b.revocation[:])
-	return &ChannelContribution{
+func (b *bobNode) SingleContribution(aliceCommitKey *btcec.PublicKey) *lnwallet.ChannelContribution {
+	revokeKey := lnwallet.DeriveRevocationPubkey(aliceCommitKey, b.revocation[:])
+	return &lnwallet.ChannelContribution{
 		FundingAmount:   b.fundingAmt,
 		MultiSigKey:     b.channelKey,
 		CommitKey:       b.channelKey,
@@ -139,8 +141,8 @@ func (b *bobNode) SingleContribution(aliceCommitKey *btcec.PublicKey) *ChannelCo
 // signFundingTx generates signatures for all the inputs in the funding tx
 // belonging to Bob.
 // NOTE: This generates the full witness stack.
-func (b *bobNode) signFundingTx(fundingTx *wire.MsgTx) ([]*InputScript, error) {
-	bobInputScripts := make([]*InputScript, 0, len(b.availableOutputs))
+func (b *bobNode) signFundingTx(fundingTx *wire.MsgTx) ([]*lnwallet.InputScript, error) {
+	bobInputScripts := make([]*lnwallet.InputScript, 0, len(b.availableOutputs))
 	bobPkScript := b.changeOutputs[0].PkScript
 
 	inputValue := int64(7e8)
@@ -158,7 +160,7 @@ func (b *bobNode) signFundingTx(fundingTx *wire.MsgTx) ([]*InputScript, error) {
 			return nil, err
 		}
 
-		inputScript := &InputScript{Witness: witness}
+		inputScript := &lnwallet.InputScript{Witness: witness}
 		bobInputScripts = append(bobInputScripts, inputScript)
 	}
 
@@ -217,7 +219,7 @@ func newBobNode(miner *rpctest.Harness, amt btcutil.Amount) (*bobNode, error) {
 	if err != nil {
 		return nil, err
 	}
-	found, index := findScriptOutputIndex(tx.MsgTx(), bobAddrScript)
+	found, index := lnwallet.FindScriptOutputIndex(tx.MsgTx(), bobAddrScript)
 	if !found {
 		return nil, fmt.Errorf("output to bob never created")
 	}
@@ -251,14 +253,14 @@ func newBobNode(miner *rpctest.Harness, amt btcutil.Amount) (*bobNode, error) {
 	}, nil
 }
 
-func loadTestCredits(miner *rpctest.Harness, w *LightningWallet, numOutputs, btcPerOutput int) error {
+func loadTestCredits(miner *rpctest.Harness, w *lnwallet.LightningWallet, numOutputs, btcPerOutput int) error {
 	// Using the mining node, spend from a coinbase output numOutputs to
 	// give us btcPerOutput with each output.
 	satoshiPerOutput := int64(btcPerOutput * 1e8)
 	addrs := make([]btcutil.Address, 0, numOutputs)
 	for i := 0; i < numOutputs; i++ {
 		// Grab a fresh address from the wallet to house this output.
-		walletAddr, err := w.NewAddress(waddrmgr.DefaultAccountNum, waddrmgr.WitnessPubKey)
+		walletAddr, err := w.NewAddress(lnwallet.WitnessPubKey, false)
 		if err != nil {
 			return err
 		}
@@ -285,87 +287,59 @@ func loadTestCredits(miner *rpctest.Harness, w *LightningWallet, numOutputs, btc
 		return err
 	}
 
-	_, bestHeight, err := miner.Node.GetBestBlock()
-	if err != nil {
-		return err
-	}
-
 	// Wait until the wallet has finished syncing up to the main chain.
 	ticker := time.NewTicker(100 * time.Millisecond)
+	expectedBalance := btcutil.Amount(satoshiPerOutput * int64(numOutputs))
 out:
 	for {
 		select {
 		case <-ticker.C:
-			if w.Manager.SyncedTo().Height == bestHeight {
+			balance, err := w.ConfirmedBalance(1, false)
+			if err != nil {
+				return err
+			}
+			if balance == expectedBalance {
 				break out
 			}
 		}
 	}
 	ticker.Stop()
 
-	// Trigger a re-scan to ensure the wallet knows of the newly created
-	// outputs it can spend.
-	if err := w.Rescan(addrs, nil); err != nil {
-		return err
-	}
-
 	return nil
 }
 
 // createTestWallet creates a test LightningWallet will a total of 20BTC
 // available for funding channels.
-func createTestWallet(miningNode *rpctest.Harness, netParams *chaincfg.Params) (string, *LightningWallet, error) {
-	privPass := []byte("private-test")
-	tempTestDir, err := ioutil.TempDir("", "lnwallet")
-	if err != nil {
-		return "", nil, nil
-	}
-
-	rpcConfig := miningNode.RPCConfig()
-	config := &Config{
-		PrivatePass: privPass,
-		HdSeed:      testHdSeed[:],
-		DataDir:     tempTestDir,
-		NetParams:   netParams,
-		RpcHost:     rpcConfig.Host,
-		RpcUser:     rpcConfig.User,
-		RpcPass:     rpcConfig.Pass,
-		CACert:      rpcConfig.Certificates,
-	}
+func createTestWallet(tempTestDir string, miningNode *rpctest.Harness,
+	netParams *chaincfg.Params, notifier chainntnfs.ChainNotifier,
+	wc lnwallet.WalletController, signer lnwallet.Signer,
+	bio lnwallet.BlockChainIO) (*lnwallet.LightningWallet, error) {
 
 	dbDir := filepath.Join(tempTestDir, "cdb")
 	cdb, err := channeldb.Open(dbDir, &chaincfg.SegNet4Params)
 	if err != nil {
-		return "", nil, err
+		return nil, err
 	}
 
-	chainNotifier, err := btcdnotify.New(&rpcConfig)
+	wallet, err := lnwallet.NewLightningWallet(cdb, notifier, wc, signer,
+		bio, netParams)
 	if err != nil {
-		return "", nil, err
-	}
-	if err := chainNotifier.Start(); err != nil {
-		return "", nil, err
+		return nil, err
 	}
 
-	wallet, err := NewLightningWallet(config, cdb, chainNotifier)
-	if err != nil {
-		return "", nil, err
-	}
 	if err := wallet.Startup(); err != nil {
-		return "", nil, err
+		return nil, err
 	}
 
-	cdb.RegisterCryptoSystem(&WaddrmgrEncryptorDecryptor{wallet.Manager})
-
-	// Load our test wallet with 10 outputs each holding 4BTC.
-	if err := loadTestCredits(miningNode, wallet, 10, 4); err != nil {
-		return "", nil, err
+	// Load our test wallet with 20 outputs each holding 4BTC.
+	if err := loadTestCredits(miningNode, wallet, 20, 4); err != nil {
+		return nil, err
 	}
 
-	return tempTestDir, wallet, nil
+	return wallet, nil
 }
 
-func testDualFundingReservationWorkflow(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
+func testDualFundingReservationWorkflow(miner *rpctest.Harness, wallet *lnwallet.LightningWallet, t *testing.T) {
 	// Create the bob-test wallet which will be the other side of our funding
 	// channel.
 	fundingAmount := btcutil.Amount(5 * 1e8)
@@ -376,7 +350,7 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness, lnwallet *Lightn
 
 	// Bob initiates a channel funded with 5 BTC for each side, so 10
 	// BTC total. He also generates 2 BTC in change.
-	chanReservation, err := lnwallet.InitChannelReservation(fundingAmount*2,
+	chanReservation, err := wallet.InitChannelReservation(fundingAmount*2,
 		fundingAmount, bobNode.id, numReqConfs, 4)
 	if err != nil {
 		t.Fatalf("unable to initialize funding reservation: %v", err)
@@ -426,10 +400,13 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness, lnwallet *Lightn
 	if ourContribution.RevocationKey == nil {
 		t.Fatalf("alice's revocation key not found")
 	}
+
 	// Additionally, the funding tx should have been populated.
-	if chanReservation.fundingTx == nil {
+	fundingTx := chanReservation.FinalFundingTx()
+	if fundingTx == nil {
 		t.Fatalf("funding transaction never created!")
 	}
+
 	// Their funds should also be filled in.
 	if len(theirContribution.Inputs) != 1 {
 		t.Fatalf("bob's outputs for funding tx not properly selected, have %v "+
@@ -455,13 +432,13 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness, lnwallet *Lightn
 
 	// Alice responds with her output, change addr, multi-sig key and signatures.
 	// Bob then responds with his signatures.
-	bobsSigs, err := bobNode.signFundingTx(chanReservation.fundingTx)
+	bobsSigs, err := bobNode.signFundingTx(fundingTx)
 	if err != nil {
 		t.Fatalf("unable to sign inputs for bob: %v", err)
 	}
 	commitSig, err := bobNode.signCommitTx(
-		chanReservation.partialState.OurCommitTx,
-		chanReservation.partialState.FundingRedeemScript,
+		chanReservation.LocalCommitTx(),
+		chanReservation.FundingRedeemScript(),
 		10e8)
 	if err != nil {
 		t.Fatalf("bob is unable to sign alice's commit tx: %v", err)
@@ -474,10 +451,9 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness, lnwallet *Lightn
 	// txn hits a "comfortable" depth.
 
 	// The resulting active channel state should have been persisted to the DB.
-	fundingTx := chanReservation.FinalFundingTx()
 	fundingSha := fundingTx.TxSha()
 	nodeID := wire.ShaHash(bobNode.id)
-	channels, err := lnwallet.channelDB.FetchOpenChannels(&nodeID)
+	channels, err := wallet.ChannelDB.FetchOpenChannels(&nodeID)
 	if err != nil {
 		t.Fatalf("unable to retrieve channel from DB: %v", err)
 	}
@@ -495,46 +471,49 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness, lnwallet *Lightn
 	if err != nil {
 		t.Fatalf("unable to init cooperative closure: %v", err)
 	}
+	aliceCloseSig = append(aliceCloseSig, byte(txscript.SigHashAll))
+
+	chanInfo := lnc.StateSnapshot()
 
 	// Obtain bob's signature for the closure transaction.
-	redeemScript := lnc.channelState.FundingRedeemScript
+	redeemScript := lnc.FundingRedeemScript
 	fundingOut := lnc.ChannelPoint()
 	fundingTxIn := wire.NewTxIn(fundingOut, nil, nil)
-	bobCloseTx := createCooperativeCloseTx(fundingTxIn,
-		lnc.channelState.TheirBalance, lnc.channelState.OurBalance,
-		lnc.channelState.TheirDeliveryScript, lnc.channelState.OurDeliveryScript,
+	bobCloseTx := lnwallet.CreateCooperativeCloseTx(fundingTxIn,
+		chanInfo.RemoteBalance, chanInfo.LocalBalance,
+		lnc.RemoteDeliveryScript, lnc.LocalDeliveryScript,
 		false)
-	bobSig, err := bobNode.signCommitTx(bobCloseTx,
-		redeemScript,
-		int64(lnc.channelState.Capacity))
+	bobSig, err := bobNode.signCommitTx(bobCloseTx, redeemScript, int64(lnc.Capacity))
 	if err != nil {
 		t.Fatalf("unable to generate bob's signature for closing tx: %v", err)
 	}
 
 	// Broadcast the transaction to the network. This transaction should
 	// be accepted, and found in the next mined block.
-	ourKey := lnc.channelState.OurMultiSigKey.PubKey().SerializeCompressed()
-	theirKey := lnc.channelState.TheirMultiSigKey.SerializeCompressed()
-	witness := spendMultiSig(redeemScript, ourKey, aliceCloseSig,
+	ourKey := chanReservation.OurContribution().MultiSigKey.SerializeCompressed()
+	theirKey := chanReservation.TheirContribution().MultiSigKey.SerializeCompressed()
+	witness := lnwallet.SpendMultiSig(redeemScript, ourKey, aliceCloseSig,
 		theirKey, bobSig)
 	bobCloseTx.TxIn[0].Witness = witness
-	if err := lnwallet.PublishTransaction(bobCloseTx); err != nil {
+	if err := wallet.PublishTransaction(bobCloseTx); err != nil {
 		t.Fatalf("broadcast of close tx rejected: %v", err)
 	}
 }
 
-func testFundingTransactionLockedOutputs(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
+func testFundingTransactionLockedOutputs(miner *rpctest.Harness,
+	wallet *lnwallet.LightningWallet, t *testing.T) {
+
 	// Create two channels, both asking for 8 BTC each, totalling 16
 	// BTC.
 	// TODO(roasbeef): tests for concurrent funding.
 	//  * also func for below
 	fundingAmount := btcutil.Amount(8 * 1e8)
-	chanReservation1, err := lnwallet.InitChannelReservation(fundingAmount,
+	chanReservation1, err := wallet.InitChannelReservation(fundingAmount,
 		fundingAmount, testHdSeed, numReqConfs, 4)
 	if err != nil {
 		t.Fatalf("unable to initialize funding reservation 1: %v", err)
 	}
-	chanReservation2, err := lnwallet.InitChannelReservation(fundingAmount,
+	chanReservation2, err := wallet.InitChannelReservation(fundingAmount,
 		fundingAmount, testHdSeed, numReqConfs, 4)
 	if err != nil {
 		t.Fatalf("unable to initialize funding reservation 2: %v", err)
@@ -563,12 +542,12 @@ func testFundingTransactionLockedOutputs(miner *rpctest.Harness, lnwallet *Light
 	// 90 BTC. We only have around 24BTC worth of outpoints that aren't locked, so
 	// this should fail.
 	amt := btcutil.Amount(90 * 1e8)
-	failedReservation, err := lnwallet.InitChannelReservation(amt, amt,
+	failedReservation, err := wallet.InitChannelReservation(amt, amt,
 		testHdSeed, numReqConfs, 4)
 	if err == nil {
 		t.Fatalf("not error returned, should fail on coin selection")
 	}
-	if err != coinset.ErrCoinsNoSelectionAvailable {
+	if err != lnwallet.ErrInsufficientFunds {
 		t.Fatalf("error not coinselect error: %v", err)
 	}
 	if failedReservation != nil {
@@ -576,28 +555,30 @@ func testFundingTransactionLockedOutputs(miner *rpctest.Harness, lnwallet *Light
 	}
 }
 
-func testFundingCancellationNotEnoughFunds(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
-	// Create a reservation for 22 BTC.
-	fundingAmount := btcutil.Amount(22 * 1e8)
-	chanReservation, err := lnwallet.InitChannelReservation(fundingAmount,
+func testFundingCancellationNotEnoughFunds(miner *rpctest.Harness,
+	wallet *lnwallet.LightningWallet, t *testing.T) {
+
+	// Create a reservation for 44 BTC.
+	fundingAmount := btcutil.Amount(44 * 1e8)
+	chanReservation, err := wallet.InitChannelReservation(fundingAmount,
 		fundingAmount, testHdSeed, numReqConfs, 4)
 	if err != nil {
 		t.Fatalf("unable to initialize funding reservation: %v", err)
 	}
 
-	// There should be three locked outpoints.
-	lockedOutPoints := lnwallet.LockedOutpoints()
-	if len(lockedOutPoints) != 6 {
+	// There should be 12 locked outpoints.
+	lockedOutPoints := wallet.LockedOutpoints()
+	if len(lockedOutPoints) != 12 {
 		t.Fatalf("two outpoints should now be locked, instead %v are",
 			len(lockedOutPoints))
 	}
 
-	// Attempt to create another channel with 22 BTC, this should fail.
-	failedReservation, err := lnwallet.InitChannelReservation(fundingAmount,
+	// Attempt to create another channel with 44 BTC, this should fail.
+	_, err = wallet.InitChannelReservation(fundingAmount,
 		fundingAmount, testHdSeed, numReqConfs, 4)
-	if err != coinset.ErrCoinsNoSelectionAvailable {
-		t.Fatalf("coin selection succeded should have insufficient funds: %+v",
-			failedReservation)
+	if err != lnwallet.ErrInsufficientFunds {
+		t.Fatalf("coin selection succeded should have insufficient funds: %v",
+			err)
 	}
 
 	// Now cancel that old reservation.
@@ -606,15 +587,16 @@ func testFundingCancellationNotEnoughFunds(miner *rpctest.Harness, lnwallet *Lig
 	}
 
 	// Those outpoints should no longer be locked.
-	lockedOutPoints = lnwallet.LockedOutpoints()
+	lockedOutPoints = wallet.LockedOutpoints()
 	if len(lockedOutPoints) != 0 {
 		t.Fatalf("outpoints still locked")
 	}
 
-	// Reservation ID should now longer be tracked.
-	_, ok := lnwallet.fundingLimbo[chanReservation.reservationID]
-	if ok {
-		t.Fatalf("funding reservation still in map")
+	// Reservation ID should no longer be tracked.
+	numReservations := wallet.ActiveReservations()
+	if len(wallet.ActiveReservations()) != 0 {
+		t.Fatalf("should have 0 reservations, instead have %v",
+			numReservations)
 	}
 
 	// TODO(roasbeef): create method like Balance that ignores locked
@@ -622,16 +604,18 @@ func testFundingCancellationNotEnoughFunds(miner *rpctest.Harness, lnwallet *Lig
 	// attempting coin selection.
 
 	// Request to fund a new channel should now succeeed.
-	_, err = lnwallet.InitChannelReservation(fundingAmount, fundingAmount,
+	_, err = wallet.InitChannelReservation(fundingAmount, fundingAmount,
 		testHdSeed, numReqConfs, 4)
 	if err != nil {
 		t.Fatalf("unable to initialize funding reservation: %v", err)
 	}
 }
 
-func testCancelNonExistantReservation(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
+func testCancelNonExistantReservation(miner *rpctest.Harness,
+	wallet *lnwallet.LightningWallet, t *testing.T) {
+
 	// Create our own reservation, give it some ID.
-	res := newChannelReservation(1000, 1000, 5000, lnwallet, 22, numReqConfs)
+	res := lnwallet.NewChannelReservation(1000, 1000, 5000, wallet, 22, numReqConfs)
 
 	// Attempt to cancel this reservation. This should fail, we know
 	// nothing of it.
@@ -640,7 +624,9 @@ func testCancelNonExistantReservation(miner *rpctest.Harness, lnwallet *Lightnin
 	}
 }
 
-func testSingleFunderReservationWorkflowInitiator(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
+func testSingleFunderReservationWorkflowInitiator(miner *rpctest.Harness,
+	lnwallet *lnwallet.LightningWallet, t *testing.T) {
+
 	// For this scenario, we (lnwallet) will be the channel initiator while bob
 	// will be the recipient.
 
@@ -702,7 +688,7 @@ func testSingleFunderReservationWorkflowInitiator(miner *rpctest.Harness, lnwall
 		t.Fatalf("commitment sig not found")
 	}
 	// Additionally, the funding tx should have been populated.
-	if chanReservation.fundingTx == nil {
+	if chanReservation.FinalFundingTx() == nil {
 		t.Fatalf("funding transaction never created!")
 	}
 	// Their funds should also be filled in.
@@ -737,8 +723,8 @@ func testSingleFunderReservationWorkflowInitiator(miner *rpctest.Harness, lnwall
 	// Now Bob can generate a signature for our version of the commitment
 	// transaction, allowing us to complete the reservation.
 	bobCommitSig, err := bobNode.signCommitTx(
-		chanReservation.partialState.OurCommitTx,
-		chanReservation.partialState.FundingRedeemScript,
+		chanReservation.LocalCommitTx(),
+		chanReservation.FundingRedeemScript(),
 		int64(fundingAmt))
 	if err != nil {
 		t.Fatalf("bob is unable to sign alice's commit tx: %v", err)
@@ -755,7 +741,7 @@ func testSingleFunderReservationWorkflowInitiator(miner *rpctest.Harness, lnwall
 	fundingTx := chanReservation.FinalFundingTx()
 	fundingSha := fundingTx.TxSha()
 	nodeID := wire.ShaHash(bobNode.id)
-	channels, err := lnwallet.channelDB.FetchOpenChannels(&nodeID)
+	channels, err := lnwallet.ChannelDB.FetchOpenChannels(&nodeID)
 	if err != nil {
 		t.Fatalf("unable to retrieve channel from DB: %v", err)
 	}
@@ -768,7 +754,9 @@ func testSingleFunderReservationWorkflowInitiator(miner *rpctest.Harness, lnwall
 	assertChannelOpen(t, miner, uint32(numReqConfs), chanReservation.DispatchChan())
 }
 
-func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
+func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness,
+	wallet *lnwallet.LightningWallet, t *testing.T) {
+
 	// For this scenario, bob will initiate the channel, while we simply act as
 	// the responder.
 	capacity := btcutil.Amount(4 * 1e8)
@@ -783,7 +771,7 @@ func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness, lnwall
 	// Bob sends over a single funding request, so we allocate our
 	// contribution and the necessary resources.
 	fundingAmt := btcutil.Amount(0)
-	chanReservation, err := lnwallet.InitChannelReservation(capacity,
+	chanReservation, err := wallet.InitChannelReservation(capacity,
 		fundingAmt, bobNode.id, numReqConfs, 4)
 	if err != nil {
 		t.Fatalf("unable to init channel reservation: %v", err)
@@ -821,7 +809,7 @@ func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness, lnwall
 	if err := chanReservation.ProcessSingleContribution(bobContribution); err != nil {
 		t.Fatalf("unable to process bob's contribution: %v", err)
 	}
-	if chanReservation.fundingTx != nil {
+	if chanReservation.FinalFundingTx() != nil {
 		t.Fatalf("funding transaction populated!")
 	}
 	if len(bobContribution.Inputs) != 1 {
@@ -848,7 +836,7 @@ func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness, lnwall
 		t.Fatalf("bob's revocaiton key not found")
 	}
 
-	fundingRedeemScript, multiOut, err := genFundingPkScript(
+	fundingRedeemScript, multiOut, err := lnwallet.GenFundingPkScript(
 		ourContribution.MultiSigKey.SerializeCompressed(),
 		bobContribution.MultiSigKey.SerializeCompressed(),
 		int64(capacity))
@@ -872,11 +860,11 @@ func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness, lnwall
 	// wallet so it can finalize the transaction by signing bob's commitment
 	// transaction.
 	fundingTxID := fundingTx.TxSha()
-	_, multiSigIndex := findScriptOutputIndex(fundingTx, multiOut.PkScript)
+	_, multiSigIndex := lnwallet.FindScriptOutputIndex(fundingTx, multiOut.PkScript)
 	fundingOutpoint := wire.NewOutPoint(&fundingTxID, multiSigIndex)
 
 	fundingTxIn := wire.NewTxIn(fundingOutpoint, nil, nil)
-	aliceCommitTx, err := createCommitTx(fundingTxIn, ourContribution.CommitKey,
+	aliceCommitTx, err := lnwallet.CreateCommitTx(fundingTxIn, ourContribution.CommitKey,
 		bobContribution.CommitKey, ourContribution.RevocationKey,
 		ourContribution.CsvDelay, 0, capacity)
 	if err != nil {
@@ -897,10 +885,9 @@ func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness, lnwall
 	}
 
 	// Alice should have saved the funding output.
-	if chanReservation.partialState.FundingOutpoint != fundingOutpoint {
+	if chanReservation.FundingOutpoint() != fundingOutpoint {
 		t.Fatalf("funding outputs don't match: %#v vs %#v",
-			chanReservation.partialState.FundingOutpoint,
-			fundingOutpoint)
+			chanReservation.FundingOutpoint(), fundingOutpoint)
 	}
 
 	// Some period of time later, Bob presents us with an SPV proof
@@ -913,13 +900,13 @@ func testSingleFunderReservationWorkflowResponder(miner *rpctest.Harness, lnwall
 	// TODO(roasbeef): bob verify alice's sig
 }
 
-func testFundingReservationInvalidCounterpartySigs(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
+func testFundingReservationInvalidCounterpartySigs(miner *rpctest.Harness, lnwallet *lnwallet.LightningWallet, t *testing.T) {
 }
 
-func testFundingTransactionTxFees(miner *rpctest.Harness, lnwallet *LightningWallet, t *testing.T) {
+func testFundingTransactionTxFees(miner *rpctest.Harness, lnwallet *lnwallet.LightningWallet, t *testing.T) {
 }
 
-var walletTests = []func(miner *rpctest.Harness, w *LightningWallet, test *testing.T){
+var walletTests = []func(miner *rpctest.Harness, w *lnwallet.LightningWallet, test *testing.T){
 	testDualFundingReservationWorkflow,
 	testSingleFunderReservationWorkflowInitiator,
 	testSingleFunderReservationWorkflowResponder,
@@ -934,20 +921,29 @@ var walletTests = []func(miner *rpctest.Harness, w *LightningWallet, test *testi
 }
 
 type testLnWallet struct {
-	lnwallet    *LightningWallet
+	lnwallet    *lnwallet.LightningWallet
 	cleanUpFunc func()
 }
 
-func clearWalletState(w *LightningWallet) error {
-	w.nextFundingID = 0
-	w.fundingLimbo = make(map[uint64]*ChannelReservation)
-	w.ResetLockedOutpoints()
-
+func clearWalletState(w *lnwallet.LightningWallet) error {
 	// TODO(roasbeef): should also restore outputs to original state.
+	w.ResetReservations()
 
-	return w.channelDB.Wipe()
+	return w.ChannelDB.Wipe()
 }
 
+// TestInterfaces tests all registered interfaces with a unified set of tests
+// which excersie each of the required methods found within the WalletController
+// interface.
+//
+// NOTE: In the future, when additional implementations of the WalletController
+// interface have been implemented, in order to ensure the new concrete
+// implementation is automatically tested, two steps must be undertaken. First,
+// one needs add a "non-captured" (_) import from the new sub-package. This
+// import should trigger an init() method within the package which registeres
+// the interface. Second, an additional case in the switch within the main loop
+// below needs to be added which properly initializes the interface.
+//
 // TODO(roasbeef): purge bobNode in favor of dual lnwallet's
 func TestLightningWallet(t *testing.T) {
 	netParams := &chaincfg.SimNetParams
@@ -965,27 +961,72 @@ func TestLightningWallet(t *testing.T) {
 		t.Fatalf("unable to set up mining node: %v", err)
 	}
 
-	// Funding via 10 outputs with 4BTC each.
-	testDir, lnwallet, err := createTestWallet(miningNode, netParams)
+	rpcConfig := miningNode.RPCConfig()
+
+	chainNotifier, err := btcdnotify.New(&rpcConfig)
 	if err != nil {
-		t.Fatalf("unable to create test ln wallet: %v", err)
+		t.Fatalf("unable to create notifier: %v", err)
+	}
+	if err := chainNotifier.Start(); err != nil {
+		t.Fatalf("unable to start notifier: %v", err)
 	}
-	defer os.RemoveAll(testDir)
-	defer lnwallet.Shutdown()
 
-	// The wallet should now have 40BTC available for spending.
-	assertProperBalance(t, lnwallet, 1, 40)
-
-	// Execute every test, clearing possibly mutated wallet state after
-	// each step.
-	for _, walletTest := range walletTests {
-		walletTest(miningNode, lnwallet, t)
-
-		// TODO(roasbeef): possible reset mining node's chainstate to
-		// initial level, cleanly wipe buckets
-		if err := clearWalletState(lnwallet); err != nil &&
-			err != bolt.ErrBucketNotFound {
-			t.Fatalf("unable to wipe wallet state: %v", err)
+	var bio lnwallet.BlockChainIO
+	var signer lnwallet.Signer
+	var wc lnwallet.WalletController
+	for _, walletDriver := range lnwallet.RegisteredWallets() {
+		tempTestDir, err := ioutil.TempDir("", "lnwallet")
+		if err != nil {
+			t.Fatalf("unable to create temp directory: %v", err)
 		}
+		defer os.RemoveAll(tempTestDir)
+
+		walletType := walletDriver.WalletType
+		switch walletType {
+		case "btcwallet":
+			btcwalletConfig := &btcwallet.Config{
+				PrivatePass: privPass,
+				HdSeed:      testHdSeed[:],
+				DataDir:     tempTestDir,
+				NetParams:   netParams,
+				RpcHost:     rpcConfig.Host,
+				RpcUser:     rpcConfig.User,
+				RpcPass:     rpcConfig.Pass,
+				CACert:      rpcConfig.Certificates,
+			}
+			wc, err = walletDriver.New(btcwalletConfig)
+			if err != nil {
+				t.Fatalf("unable to create btcwallet: %v", err)
+			}
+			signer = wc.(*btcwallet.BtcWallet)
+			bio = wc.(*btcwallet.BtcWallet)
+		default:
+			t.Fatalf("unknown wallet driver: %v", walletType)
+		}
+
+		// Funding via 20 outputs with 4BTC each.
+		lnwallet, err := createTestWallet(tempTestDir, miningNode, netParams,
+			chainNotifier, wc, signer, bio)
+		if err != nil {
+			t.Fatalf("unable to create test ln wallet: %v", err)
+		}
+
+		// The wallet should now have 80BTC available for spending.
+		assertProperBalance(t, lnwallet, 1, 80)
+
+		// Execute every test, clearing possibly mutated wallet state after
+		// each step.
+		for _, walletTest := range walletTests {
+			walletTest(miningNode, lnwallet, t)
+
+			// TODO(roasbeef): possible reset mining node's chainstate to
+			// initial level, cleanly wipe buckets
+			if err := clearWalletState(lnwallet); err != nil &&
+				err != bolt.ErrBucketNotFound {
+				t.Fatalf("unable to wipe wallet state: %v", err)
+			}
+		}
+
+		lnwallet.Shutdown()
 	}
 }

lnwallet/reservation.go

@@ -88,7 +88,6 @@ type InputScript struct {
 //       as a signature to our version of the commitment transaction.
 //     * We then verify the validity of all signatures before considering the
 //       channel "open".
-// TODO(roasbeef): update with single funder description
 type ChannelReservation struct {
 	// This mutex MUST be held when either reading or modifying any of the
 	// fields below.
@@ -131,11 +130,11 @@ type ChannelReservation struct {
 	wallet *LightningWallet
 }
 
-// newChannelReservation creates a new channel reservation. This function is
+// NewChannelReservation creates a new channel reservation. This function is
 // used only internally by lnwallet. In order to concurrent safety, the creation
 // of all channel reservations should be carried out via the
 // lnwallet.InitChannelReservation interface.
-func newChannelReservation(capacity, fundingAmt btcutil.Amount, minFeeRate btcutil.Amount,
+func NewChannelReservation(capacity, fundingAmt btcutil.Amount, minFeeRate btcutil.Amount,
 	wallet *LightningWallet, id uint64, numConfs uint16) *ChannelReservation {
 	var ourBalance btcutil.Amount
 	var theirBalance btcutil.Amount
@@ -160,7 +159,7 @@ func newChannelReservation(capacity, fundingAmt btcutil.Amount, minFeeRate btcut
 			OurBalance:   ourBalance,
 			TheirBalance: theirBalance,
 			MinFeePerKb:  minFeeRate,
-			Db:           wallet.channelDB,
+			Db:           wallet.ChannelDB,
 		},
 		numConfsToOpen: numConfs,
 		reservationID:  id,
@@ -315,6 +314,26 @@ func (r *ChannelReservation) FinalFundingTx() *wire.MsgTx {
 	return r.fundingTx
 }
 
+// FundingRedeemScript returns the fully populated funding redeem script.
+//
+// NOTE: This method will only return a non-nil value after either
+// ProcesContribution or ProcessSingleContribution have been executed and
+// returned without error.
+func (r *ChannelReservation) FundingRedeemScript() []byte {
+	r.RLock()
+	defer r.RUnlock()
+	return r.partialState.FundingRedeemScript
+}
+
+// LocalCommitTx returns the commitment transaction for the local node involved
+// in this funding reservation.
+func (r *ChannelReservation) LocalCommitTx() *wire.MsgTx {
+	r.RLock()
+	defer r.RUnlock()
+
+	return r.partialState.OurCommitTx
+}
+
 // FundingOutpoint returns the outpoint of the funding transaction.
 //
 // NOTE: The pointer returned will only be set once the .ProcesContribution()
@@ -346,6 +365,7 @@ func (r *ChannelReservation) Cancel() error {
 // transaction for this pending payment channel obtains the configured number
 // of confirmations. Once confirmations have been obtained, a fully initialized
 // LightningChannel instance is returned, allowing for channel updates.
+//
 // NOTE: If this method is called before .CompleteReservation(), it will block
 // indefinitely.
 func (r *ChannelReservation) DispatchChan() <-chan *LightningChannel {

lnwallet/script_utils.go

@@ -58,9 +58,9 @@ func genMultiSigScript(aPub, bPub []byte) ([]byte, error) {
 	return bldr.Script()
 }
 
-// genFundingPkScript creates a redeem script, and its matching p2wsh
+// GenFundingPkScript creates a redeem script, and its matching p2wsh
 // output for the funding transaction.
-func genFundingPkScript(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, error) {
+func GenFundingPkScript(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, error) {
 	// As a sanity check, ensure that the passed amount is above zero.
 	if amt <= 0 {
 		return nil, nil, fmt.Errorf("can't create FundTx script with " +
@@ -85,7 +85,7 @@ func genFundingPkScript(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, erro
 
 // spendMultiSig generates the witness stack required to redeem the 2-of-2 p2wsh
 // multi-sig output.
-func spendMultiSig(redeemScript, pubA, sigA, pubB, sigB []byte) [][]byte {
+func SpendMultiSig(redeemScript, pubA, sigA, pubB, sigB []byte) [][]byte {
 	witness := make([][]byte, 4)
 
 	// When spending a p2wsh multi-sig script, rather than an OP_0, we add
@@ -114,7 +114,8 @@ func spendMultiSig(redeemScript, pubA, sigA, pubB, sigB []byte) [][]byte {
 // matching 'script'. Additionally, a boolean is returned indicating if
 // a matching output was found at all.
 // NOTE: The search stops after the first matching script is found.
-func findScriptOutputIndex(tx *wire.MsgTx, script []byte) (bool, uint32) {
+// TODO(roasbeef): shouldn't be public?
+func FindScriptOutputIndex(tx *wire.MsgTx, script []byte) (bool, uint32) {
 	found := false
 	index := uint32(0)
 	for i, txOut := range tx.TxOut {
@@ -670,7 +671,7 @@ func commitSpendNoDelay(commitScript []byte, outputAmt btcutil.Amount,
 	return wire.TxWitness(witness), nil
 }
 
-// deriveRevocationPubkey derives the revocation public key given the
+// DeriveRevocationPubkey derives the revocation public key given the
 // counter-party's commitment key, and revocation pre-image derived via a
 // pseudo-random-function. In the event that we (for some reason) broadcast a
 // revoked commitment transaction, then if the other party knows the revocation
@@ -689,7 +690,7 @@ func commitSpendNoDelay(commitScript []byte, outputAmt btcutil.Amount,
 //   revokePriv := commitPriv + revokePreimge mod N
 //
 // Where N is the order of the sub-group.
-func deriveRevocationPubkey(commitPubKey *btcec.PublicKey,
+func DeriveRevocationPubkey(commitPubKey *btcec.PublicKey,
 	revokePreimage []byte) *btcec.PublicKey {
 
 	// First we need to convert the revocation hash into a point on the
@@ -703,7 +704,7 @@ func deriveRevocationPubkey(commitPubKey *btcec.PublicKey,
 	return &btcec.PublicKey{X: revokeX, Y: revokeY}
 }
 
-// deriveRevocationPrivKey derives the revocation private key given a node's
+// DeriveRevocationPrivKey derives the revocation private key given a node's
 // commitment private key, and the pre-image to a previously seen revocation
 // hash. Using this derived private key, a node is able to claim the output
 // within the commitment transaction of a node in the case that they broadcast
@@ -713,7 +714,7 @@ func deriveRevocationPubkey(commitPubKey *btcec.PublicKey,
 //   revokePriv := commitPriv + revokePreimage mod N
 //
 // Where N is the order of the sub-group.
-func deriveRevocationPrivKey(commitPrivKey *btcec.PrivateKey,
+func DeriveRevocationPrivKey(commitPrivKey *btcec.PrivateKey,
 	revokePreimage []byte) *btcec.PrivateKey {
 
 	// Convert the revocation pre-image into a scalar value so we can
@@ -742,12 +743,13 @@ func deriveRevocationPrivKey(commitPrivKey *btcec.PrivateKey,
 //
 // [1]: https://eprint.iacr.org/2010/264.pdf
 // [2]: https://tools.ietf.org/html/rfc5869
-func deriveElkremRoot(localMultiSigKey *btcec.PrivateKey,
+func deriveElkremRoot(elkremDerivationRoot *btcec.PrivateKey,
+	localMultiSigKey *btcec.PublicKey,
 	remoteMultiSigKey *btcec.PublicKey) wire.ShaHash {
 
-	secret := localMultiSigKey.Serialize()
-	salt := remoteMultiSigKey.SerializeCompressed()
-	info := []byte("elkrem")
+	secret := elkremDerivationRoot.Serialize()
+	salt := localMultiSigKey.SerializeCompressed()
+	info := remoteMultiSigKey.SerializeCompressed()
 
 	rootReader := hkdf.New(sha256.New, secret, salt, info)
 

lnwallet/script_utils_test.go

@@ -41,7 +41,7 @@ func TestCommitmentSpendValidation(t *testing.T) {
 	channelBalance := btcutil.Amount(1 * 10e8)
 	csvTimeout := uint32(5)
 	revocationPreimage := testHdSeed[:]
-	revokePubKey := deriveRevocationPubkey(bobKeyPub, revocationPreimage)
+	revokePubKey := DeriveRevocationPubkey(bobKeyPub, revocationPreimage)
 
 	// With all the test data set up, we create the commitment transaction.
 	// We only focus on a single party's transactions, as the scripts are
@@ -50,7 +50,7 @@ func TestCommitmentSpendValidation(t *testing.T) {
 	// This is Alice's commitment transaction, so she must wait a CSV delay
 	// of 5 blocks before sweeping the output, while bob can spend
 	// immediately with either the revocation key, or his regular key.
-	commitmentTx, err := createCommitTx(fakeFundingTxIn, aliceKeyPub,
+	commitmentTx, err := CreateCommitTx(fakeFundingTxIn, aliceKeyPub,
 		bobKeyPub, revokePubKey, csvTimeout, channelBalance, channelBalance)
 	if err != nil {
 		t.Fatalf("unable to create commitment transaction: %v", nil)
@@ -96,7 +96,7 @@ func TestCommitmentSpendValidation(t *testing.T) {
 	// Next, we'll test bob spending with the derived revocation key to
 	// simulate the scenario when alice broadcasts this commitmen
 	// transaction after it's been revoked.
-	revokePrivKey := deriveRevocationPrivKey(bobKeyPriv, revocationPreimage)
+	revokePrivKey := DeriveRevocationPrivKey(bobKeyPriv, revocationPreimage)
 	bobWitnessSpend, err := commitSpendRevoke(delayScript, channelBalance,
 		revokePrivKey, sweepTx)
 	if err != nil {
@@ -144,9 +144,9 @@ func TestRevocationKeyDerivation(t *testing.T) {
 
 	priv, pub := btcec.PrivKeyFromBytes(btcec.S256(), testWalletPrivKey)
 
-	revocationPub := deriveRevocationPubkey(pub, revocationPreimage)
+	revocationPub := DeriveRevocationPubkey(pub, revocationPreimage)
 
-	revocationPriv := deriveRevocationPrivKey(priv, revocationPreimage)
+	revocationPriv := DeriveRevocationPrivKey(priv, revocationPreimage)
 	x, y := btcec.S256().ScalarBaseMult(revocationPriv.D.Bytes())
 	derivedRevPub := &btcec.PublicKey{
 		Curve: btcec.S256(),

lnwallet/setup.go

@@ -1,26 +0,0 @@
-package lnwallet
-
-import (
-	"path/filepath"
-
-	"github.com/roasbeef/btcd/chaincfg"
-	"github.com/roasbeef/btcd/wire"
-	_ "github.com/roasbeef/btcwallet/walletdb/bdb"
-)
-
-// networkDir returns the directory name of a network directory to hold wallet
-// files.
-func networkDir(dataDir string, chainParams *chaincfg.Params) string {
-	netname := chainParams.Name
-
-	// For now, we must always name the testnet data directory as "testnet"
-	// and not "testnet3" or any other version, as the chaincfg testnet3
-	// paramaters will likely be switched to being named "testnet3" in the
-	// future.  This is done to future proof that change, and an upgrade
-	// plan to move the testnet3 data directory can be worked out later.
-	if chainParams.Net == wire.TestNet3 {
-		netname = "testnet"
-	}
-
-	return filepath.Join(dataDir, netname)
-}

lnwallet/wallet.go

@@ -4,7 +4,6 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"math"
 	"sync"
 	"sync/atomic"
 
@@ -12,23 +11,31 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/elkrem"
-	"github.com/roasbeef/btcd/btcjson"
+	"github.com/roasbeef/btcd/chaincfg"
+	"github.com/roasbeef/btcutil/hdkeychain"
 
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/txscript"
 	"github.com/roasbeef/btcd/wire"
 	"github.com/roasbeef/btcutil"
-	"github.com/roasbeef/btcutil/coinset"
 	"github.com/roasbeef/btcutil/txsort"
-	"github.com/roasbeef/btcwallet/chain"
-	"github.com/roasbeef/btcwallet/waddrmgr"
-	btcwallet "github.com/roasbeef/btcwallet/wallet"
 )
 
 const (
 	// The size of the buffered queue of requests to the wallet from the
 	// outside word.
 	msgBufferSize = 100
+
+	// elkremRootIndex is the top level HD key index from which secrets
+	// used to generate elkrem roots should be derived from.
+	elkremRootIndex = hdkeychain.HardenedKeyStart + 1
+
+	// identityKeyIndex is the top level HD key index which is used to
+	// generate/rotate identity keys.
+	//
+	// TODO(roasbeef): should instead be child to make room for future
+	// rotations, etc.
+	identityKeyIndex = hdkeychain.HardenedKeyStart + 2
 )
 
 var (
@@ -217,7 +224,7 @@ type channelOpenMsg struct {
 type LightningWallet struct {
 	// This mutex is to be held when generating external keys to be used
 	// as multi-sig, and commitment keys within the channel.
-	KeyGenMtx sync.RWMutex
+	keyGenMtx sync.RWMutex
 
 	// This mutex MUST be held when performing coin selection in order to
 	// avoid inadvertently creating multiple funding transaction which
@@ -227,25 +234,30 @@ type LightningWallet struct {
 	// A wrapper around a namespace within boltdb reserved for ln-based
 	// wallet meta-data. See the 'channeldb' package for further
 	// information.
-	channelDB *channeldb.DB
+	ChannelDB *channeldb.DB
 
 	// Used by in order to obtain notifications about funding transaction
 	// reaching a specified confirmation depth, and to catch
 	// counterparty's broadcasting revoked commitment states.
 	chainNotifier chainntnfs.ChainNotifier
 
-	// The core wallet, all non Lightning Network specific interaction is
-	// proxied to the internal wallet.
-	*btcwallet.Wallet
+	// wallet is the the core wallet, all non Lightning Network specific
+	// interaction is proxied to the internal wallet.
+	WalletController
 
-	// An active RPC connection to a full-node. In the case of a btcd node,
-	// websockets are used for notifications. If using Bitcoin Core,
-	// notifications are either generated via long-polling or the usage of
-	// ZeroMQ.
-	// TODO(roasbeef): make into interface need: getrawtransaction + gettxout
-	//  * getrawtransaction -> verify proof of channel links
-	//  * gettxout -> verify inputs to funding tx exist and are unspent
-	rpc *chain.RPCClient
+	// Signer is the wallet's current Signer implementation. This Signer is
+	// used to generate signature for all inputs to potential funding
+	// transactions, as well as for spends from the funding transaction to
+	// update the commitment state.
+	Signer Signer
+
+	// chainIO is an instance of the BlockChainIO interface. chainIO is
+	// used to lookup the existance of outputs within the utxo set.
+	chainIO BlockChainIO
+
+	// rootKey is the root HD key dervied from a WalletController private
+	// key. This rootKey is used to derive all LN specific secrets.
+	rootKey *hdkeychain.ExtendedKey
 
 	// All messages to the wallet are to be sent accross this channel.
 	msgChan chan interface{}
@@ -262,7 +274,12 @@ type LightningWallet struct {
 	// TODO(roasbeef): zombie garbage collection routine to solve
 	// lost-object/starvation problem/attack.
 
-	cfg *Config
+	// lockedOutPoints is a set of the currently locked outpoint. This
+	// information is kept in order to provide an easy way to unlock all
+	// the currently locked outpoints.
+	lockedOutPoints map[wire.OutPoint]struct{}
+
+	netParams *chaincfg.Params
 
 	started  int32
 	shutdown int32
@@ -279,86 +296,38 @@ type LightningWallet struct {
 //
 // NOTE: The passed channeldb, and ChainNotifier should already be fully
 // initialized/started before being passed as a function arugment.
-func NewLightningWallet(config *Config, cdb *channeldb.DB,
-	notifier chainntnfs.ChainNotifier) (*LightningWallet, error) {
+func NewLightningWallet(cdb *channeldb.DB, notifier chainntnfs.ChainNotifier,
+	wallet WalletController, signer Signer, bio BlockChainIO,
+	netParams *chaincfg.Params) (*LightningWallet, error) {
 
-	// Ensure the wallet exists or create it when the create flag is set.
-	netDir := networkDir(config.DataDir, config.NetParams)
+	// TODO(roasbeef): need a another wallet level config
 
-	var pubPass []byte
-	if config.PublicPass == nil {
-		pubPass = defaultPubPassphrase
-	} else {
-		pubPass = config.PublicPass
-	}
-
-	loader := btcwallet.NewLoader(config.NetParams, netDir)
-	walletExists, err := loader.WalletExists()
+	// Fetch the root derivation key from the wallet's HD chain. We'll use
+	// this to generate specific Lightning related secrets on the fly.
+	rootKey, err := wallet.FetchRootKey()
 	if err != nil {
 		return nil, err
 	}
 
-	var createID bool
-	var wallet *btcwallet.Wallet
-	if !walletExists {
-		// Wallet has never been created, perform initial set up.
-		wallet, err = loader.CreateNewWallet(pubPass, config.PrivatePass,
-			config.HdSeed)
-		if err != nil {
-			return nil, err
-		}
-
-		createID = true
-	} 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(config.PrivatePass); err != nil {
-		return nil, err
-	}
-
-	// If we just created the wallet, then reserve, and store a key for
-	// our ID within the Lightning Network.
-	if createID {
-		account := uint32(waddrmgr.DefaultAccountNum)
-		adrs, err := wallet.Manager.NextInternalAddresses(account, 1, waddrmgr.WitnessPubKey)
-		if err != nil {
-			return nil, err
-		}
-
-		idPubkeyHash := adrs[0].Address().ScriptAddress()
-		if err := cdb.PutIdKey(idPubkeyHash); err != nil {
-			return nil, err
-		}
-		walletLog.Infof("stored identity key pubkey hash in channeldb")
-	}
-
-	// Create a special websockets rpc client for btcd which will be used
-	// by the wallet for notifications, calls, etc.
-	rpcc, err := chain.NewRPCClient(config.NetParams, config.RpcHost,
-		config.RpcUser, config.RpcPass, config.CACert, false, 20)
+	// TODO(roasbeef): always re-derive on the fly?
+	rootKeyRaw := rootKey.Serialize()
+	rootMasterKey, err := hdkeychain.NewMaster(rootKeyRaw, netParams)
 	if err != nil {
 		return nil, err
 	}
 
 	return &LightningWallet{
-		chainNotifier: notifier,
-		rpc:           rpcc,
-		Wallet:        wallet,
-		channelDB:     cdb,
-		msgChan:       make(chan interface{}, msgBufferSize),
-		// TODO(roasbeef): make this atomic.Uint32 instead? Which is
-		// faster, locks or CAS? I'm guessing CAS because assembly:
-		//  * https://golang.org/src/sync/atomic/asm_amd64.s
-		nextFundingID: 0,
-		cfg:           config,
-		fundingLimbo:  make(map[uint64]*ChannelReservation),
-		quit:          make(chan struct{}),
+		rootKey:          rootMasterKey,
+		chainNotifier:    notifier,
+		Signer:           signer,
+		WalletController: wallet,
+		chainIO:          bio,
+		ChannelDB:        cdb,
+		msgChan:          make(chan interface{}, msgBufferSize),
+		nextFundingID:    0,
+		fundingLimbo:     make(map[uint64]*ChannelReservation),
+		lockedOutPoints:  make(map[wire.OutPoint]struct{}),
+		quit:             make(chan struct{}),
 	}, nil
 }
 
@@ -370,16 +339,10 @@ func (l *LightningWallet) Startup() error {
 		return nil
 	}
 
-	// Establish an RPC connection in additino to starting the goroutines
-	// in the underlying wallet.
-	if err := l.rpc.Start(); err != nil {
+	// Start the underlying wallet controller.
+	if err := l.Start(); err != nil {
 		return err
 	}
-	l.Start()
-
-	// Pass the rpc client into the wallet so it can sync up to the
-	// current main chain.
-	l.SynchronizeRPC(l.rpc)
 
 	l.wg.Add(1)
 	// TODO(roasbeef): multiple request handlers?
@@ -396,16 +359,59 @@ func (l *LightningWallet) Shutdown() error {
 
 	// Signal the underlying wallet controller to shutdown, waiting until
 	// all active goroutines have been shutdown.
-	l.Stop()
-	l.WaitForShutdown()
-
-	l.rpc.Shutdown()
+	if err := l.Stop(); err != nil {
+		return err
+	}
 
 	close(l.quit)
 	l.wg.Wait()
 	return nil
 }
 
+// LockOutpoints returns a list of all currently locked outpoint.
+func (l *LightningWallet) LockedOutpoints() []*wire.OutPoint {
+	outPoints := make([]*wire.OutPoint, 0, len(l.lockedOutPoints))
+	for outPoint := range l.lockedOutPoints {
+		outPoints = append(outPoints, &outPoint)
+	}
+
+	return outPoints
+}
+
+// ResetReservations reset the volatile wallet state which trakcs all currently
+// active reservations.
+func (l *LightningWallet) ResetReservations() {
+	l.nextFundingID = 0
+	l.fundingLimbo = make(map[uint64]*ChannelReservation)
+
+	for outpoint := range l.lockedOutPoints {
+		l.UnlockOutpoint(outpoint)
+	}
+	l.lockedOutPoints = make(map[wire.OutPoint]struct{})
+}
+
+// ActiveReservations returns a slice of all the currently active
+// (non-cancalled) reservations.
+func (l *LightningWallet) ActiveReservations() []*ChannelReservation {
+	reservations := make([]*ChannelReservation, 0, len(l.fundingLimbo))
+	for _, reservation := range l.fundingLimbo {
+		reservations = append(reservations, reservation)
+	}
+
+	return reservations
+}
+
+// GetIdentitykey returns the identity private key of the wallet.
+// TODO(roasbeef): should be moved elsewhere
+func (l *LightningWallet) GetIdentitykey() (*btcec.PrivateKey, error) {
+	identityKey, err := l.rootKey.Child(identityKeyIndex)
+	if err != nil {
+		return nil, err
+	}
+
+	return identityKey.ECPrivKey()
+}
+
 // requestHandler is the primary goroutine(s) resposible for handling, and
 // dispatching relies to all messages.
 func (l *LightningWallet) requestHandler() {
@@ -478,16 +484,9 @@ func (l *LightningWallet) InitChannelReservation(capacity,
 // handleFundingReserveRequest processes a message intending to create, and
 // validate a funding reservation request.
 func (l *LightningWallet) handleFundingReserveRequest(req *initFundingReserveMsg) {
-	// Create a limbo and record entry for this newly pending funding request.
-	l.limboMtx.Lock()
-
-	id := l.nextFundingID
-	reservation := newChannelReservation(req.capacity, req.fundingAmount,
+	id := atomic.AddUint64(&l.nextFundingID, 1)
+	reservation := NewChannelReservation(req.capacity, req.fundingAmount,
 		req.minFeeRate, l, id, req.numConfs)
-	l.nextFundingID++
-	l.fundingLimbo[id] = reservation
-
-	l.limboMtx.Unlock()
 
 	// Grab the mutex on the ChannelReservation to ensure thead-safety
 	reservation.Lock()
@@ -502,7 +501,9 @@ func (l *LightningWallet) handleFundingReserveRequest(req *initFundingReserveMsg
 	// don't need to perform any coin selection. Otherwise, attempt to
 	// obtain enough coins to meet the required funding amount.
 	if req.fundingAmount != 0 {
-		if err := l.selectCoinsAndChange(req.fundingAmount,
+		// TODO(roasbeef): consult model for proper fee rate
+		feeRate := uint64(10)
+		if err := l.selectCoinsAndChange(feeRate, req.fundingAmount,
 			ourContribution); err != nil {
 			req.err <- err
 			req.resp <- nil
@@ -513,27 +514,26 @@ func (l *LightningWallet) handleFundingReserveRequest(req *initFundingReserveMsg
 	// Grab two fresh keys from our HD chain, one will be used for the
 	// multi-sig funding transaction, and the other for the commitment
 	// transaction.
-	multiSigKey, err := l.getNextRawKey()
+	multiSigKey, err := l.NewRawKey()
 	if err != nil {
 		req.err <- err
 		req.resp <- nil
 		return
 	}
-	commitKey, err := l.getNextRawKey()
+	commitKey, err := l.NewRawKey()
 	if err != nil {
 		req.err <- err
 		req.resp <- nil
 		return
 	}
 	reservation.partialState.OurMultiSigKey = multiSigKey
-	ourContribution.MultiSigKey = multiSigKey.PubKey()
+	ourContribution.MultiSigKey = multiSigKey
 	reservation.partialState.OurCommitKey = commitKey
-	ourContribution.CommitKey = commitKey.PubKey()
+	ourContribution.CommitKey = commitKey
 
 	// Generate a fresh address to be used in the case of a cooperative
 	// channel close.
-	deliveryAddress, err := l.NewAddress(waddrmgr.DefaultAccountNum,
-		waddrmgr.WitnessPubKey)
+	deliveryAddress, err := l.NewAddress(WitnessPubKey, false)
 	if err != nil {
 		req.err <- err
 		req.resp <- nil
@@ -548,6 +548,12 @@ func (l *LightningWallet) handleFundingReserveRequest(req *initFundingReserveMsg
 	reservation.partialState.OurDeliveryScript = deliveryScript
 	ourContribution.DeliveryAddress = deliveryAddress
 
+	// Create a limbo and record entry for this newly pending funding
+	// request.
+	l.limboMtx.Lock()
+	l.fundingLimbo[id] = reservation
+	l.limboMtx.Unlock()
+
 	// Funding reservation request succesfully handled. The funding inputs
 	// will be marked as unavailable until the reservation is either
 	// completed, or cancecled.
@@ -578,6 +584,7 @@ func (l *LightningWallet) handleFundingCancelRequest(req *fundingReserveCancelMs
 	// Mark all previously locked outpoints as usuable for future funding
 	// requests.
 	for _, unusedInput := range pendingReservation.ourContribution.Inputs {
+		delete(l.lockedOutPoints, unusedInput.PreviousOutPoint)
 		l.UnlockOutpoint(unusedInput.PreviousOutPoint)
 	}
 
@@ -639,7 +646,7 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	// Finally, add the 2-of-2 multi-sig output which will set up the lightning
 	// channel.
 	channelCapacity := int64(pendingReservation.partialState.Capacity)
-	redeemScript, multiSigOut, err := genFundingPkScript(ourKey.PubKey().SerializeCompressed(),
+	redeemScript, multiSigOut, err := GenFundingPkScript(ourKey.SerializeCompressed(),
 		theirKey.SerializeCompressed(), channelCapacity)
 	if err != nil {
 		req.err <- err
@@ -647,21 +654,6 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	}
 	pendingReservation.partialState.FundingRedeemScript = redeemScript
 
-	// Register intent for notifications related to the funding output.
-	// This'll allow us to properly track the number of confirmations the
-	// funding tx has once it has been broadcasted.
-	// TODO(roasbeef): remove
-	lastBlock := l.Manager.SyncedTo()
-	scriptAddr, err := l.Manager.ImportScript(redeemScript, &lastBlock)
-	if err != nil {
-		req.err <- err
-		return
-	}
-	if err := l.rpc.NotifyReceived([]btcutil.Address{scriptAddr.Address()}); err != nil {
-		req.err <- err
-		return
-	}
-
 	// Sort the transaction. Since both side agree to a cannonical
 	// ordering, by sorting we no longer need to send the entire
 	// transaction. Only signatures will be exchanged.
@@ -671,81 +663,30 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	// Next, sign all inputs that are ours, collecting the signatures in
 	// order of the inputs.
 	pendingReservation.ourFundingInputScripts = make([]*InputScript, 0, len(ourContribution.Inputs))
-	hashCache := txscript.NewTxSigHashes(fundingTx)
+	signDesc := SignDescriptor{
+		HashType:  txscript.SigHashAll,
+		SigHashes: txscript.NewTxSigHashes(fundingTx),
+	}
 	for i, txIn := range fundingTx.TxIn {
-		// Does the wallet know about the txin?
-		txDetail, _ := l.TxStore.TxDetails(&txIn.PreviousOutPoint.Hash)
-		if txDetail == nil {
+		info, err := l.FetchInputInfo(&txIn.PreviousOutPoint)
+		if err == ErrNotMine {
 			continue
-		}
-
-		// Is this our txin?
-		prevIndex := txIn.PreviousOutPoint.Index
-		prevOut := txDetail.TxRecord.MsgTx.TxOut[prevIndex]
-		_, addrs, _, _ := txscript.ExtractPkScriptAddrs(prevOut.PkScript, l.cfg.NetParams)
-		apkh := addrs[0]
-
-		ai, err := l.Manager.Address(apkh)
-		if err != nil {
-			req.err <- fmt.Errorf("cannot get address info: %v", err)
-			return
-		}
-		pka := ai.(waddrmgr.ManagedPubKeyAddress)
-		privKey, err := pka.PrivKey()
-		if err != nil {
-			req.err <- fmt.Errorf("cannot get private key: %v", err)
+		} else if err != nil {
+			req.err <- err
 			return
 		}
 
-		var witnessProgram []byte
-		inputScript := &InputScript{}
+		signDesc.Output = info
+		signDesc.InputIndex = i
 
-		// If we're spending p2wkh output nested within a p2sh output,
-		// then we'll need to attach a sigScript in addition to witness
-		// data.
-		if pka.IsNestedWitness() {
-			pubKey := privKey.PubKey()
-			pubKeyHash := btcutil.Hash160(pubKey.SerializeCompressed())
-
-			// Next, we'll generate a valid sigScript that'll allow us to spend
-			// the p2sh output. The sigScript will contain only a single push of
-			// the p2wkh witness program corresponding to the matching public key
-			// of this address.
-			p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(pubKeyHash,
-				l.cfg.NetParams)
-			if err != nil {
-				req.err <- fmt.Errorf("unable to create p2wkh addr: %v", err)
-				return
-			}
-			witnessProgram, err = txscript.PayToAddrScript(p2wkhAddr)
-			if err != nil {
-				req.err <- fmt.Errorf("unable to create witness program: %v", err)
-				return
-			}
-			bldr := txscript.NewScriptBuilder()
-			bldr.AddData(witnessProgram)
-			sigScript, err := bldr.Script()
-			if err != nil {
-				req.err <- fmt.Errorf("unable to create scriptsig: %v", err)
-				return
-			}
-			txIn.SignatureScript = sigScript
-			inputScript.ScriptSig = sigScript
-		} else {
-			witnessProgram = prevOut.PkScript
-		}
-
-		// Generate a valid witness stack for the input.
-		inputValue := prevOut.Value
-		witnessScript, err := txscript.WitnessScript(fundingTx, hashCache, i,
-			inputValue, witnessProgram, txscript.SigHashAll, privKey, true)
+		inputScript, err := l.Signer.ComputeInputScript(fundingTx, &signDesc)
 		if err != nil {
-			req.err <- fmt.Errorf("cannot create witnessscript: %s", err)
+			req.err <- err
 			return
 		}
-		txIn.Witness = witnessScript
-		inputScript.Witness = witnessScript
 
+		txIn.SignatureScript = inputScript.ScriptSig
+		txIn.Witness = inputScript.Witness
 		pendingReservation.ourFundingInputScripts = append(
 			pendingReservation.ourFundingInputScripts,
 			inputScript,
@@ -753,10 +694,10 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	}
 
 	// Locate the index of the multi-sig outpoint in order to record it
-	// since the outputs are cannonically sorted. If this is a sigle funder
+	// since the outputs are cannonically sorted. If this is a single funder
 	// workflow, then we'll also need to send this to the remote node.
 	fundingTxID := fundingTx.TxSha()
-	_, multiSigIndex := findScriptOutputIndex(fundingTx, multiSigOut.PkScript)
+	_, multiSigIndex := FindScriptOutputIndex(fundingTx, multiSigOut.PkScript)
 	fundingOutpoint := wire.NewOutPoint(&fundingTxID, multiSigIndex)
 	pendingReservation.partialState.FundingOutpoint = fundingOutpoint
 
@@ -767,11 +708,17 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	pendingReservation.partialState.RemoteElkrem = e
 	pendingReservation.partialState.TheirCurrentRevocation = theirContribution.RevocationKey
 
+	masterElkremRoot, err := l.deriveMasterElkremRoot()
+	if err != nil {
+		req.err <- err
+		return
+	}
+
 	// Now that we have their commitment key, we can create the revocation
 	// key for the first version of our commitment transaction. To do so,
 	// we'll first create our elkrem root, then grab the first pre-iamge
 	// from it.
-	elkremRoot := deriveElkremRoot(ourKey, theirKey)
+	elkremRoot := deriveElkremRoot(masterElkremRoot, ourKey, theirKey)
 	elkremSender := elkrem.NewElkremSender(elkremRoot)
 	pendingReservation.partialState.LocalElkrem = elkremSender
 	firstPreimage, err := elkremSender.AtIndex(0)
@@ -780,7 +727,7 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 		return
 	}
 	theirCommitKey := theirContribution.CommitKey
-	ourRevokeKey := deriveRevocationPubkey(theirCommitKey, firstPreimage[:])
+	ourRevokeKey := DeriveRevocationPubkey(theirCommitKey, firstPreimage[:])
 
 	// Create the txIn to our commitment transaction; required to construct
 	// the commitment transactions.
@@ -792,14 +739,14 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	ourBalance := ourContribution.FundingAmount
 	theirBalance := theirContribution.FundingAmount
 	ourCommitKey := ourContribution.CommitKey
-	ourCommitTx, err := createCommitTx(fundingTxIn, ourCommitKey, theirCommitKey,
+	ourCommitTx, err := CreateCommitTx(fundingTxIn, ourCommitKey, theirCommitKey,
 		ourRevokeKey, ourContribution.CsvDelay,
 		ourBalance, theirBalance)
 	if err != nil {
 		req.err <- err
 		return
 	}
-	theirCommitTx, err := createCommitTx(fundingTxIn, theirCommitKey, ourCommitKey,
+	theirCommitTx, err := CreateCommitTx(fundingTxIn, theirCommitKey, ourCommitKey,
 		theirContribution.RevocationKey, theirContribution.CsvDelay,
 		theirBalance, ourBalance)
 	if err != nil {
@@ -830,10 +777,15 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 
 	// Generate a signature for their version of the initial commitment
 	// transaction.
-	hashCache = txscript.NewTxSigHashes(theirCommitTx)
-	channelBalance := pendingReservation.partialState.Capacity
-	sigTheirCommit, err := txscript.RawTxInWitnessSignature(theirCommitTx, hashCache, 0,
-		int64(channelBalance), redeemScript, txscript.SigHashAll, ourKey)
+	signDesc = SignDescriptor{
+		RedeemScript: redeemScript,
+		PubKey:       ourKey,
+		Output:       multiSigOut,
+		HashType:     txscript.SigHashAll,
+		SigHashes:    txscript.NewTxSigHashes(theirCommitTx),
+		InputIndex:   0,
+	}
+	sigTheirCommit, err := l.Signer.SignOutputRaw(theirCommitTx, &signDesc)
 	if err != nil {
 		req.err <- err
 		return
@@ -871,7 +823,7 @@ func (l *LightningWallet) handleSingleContribution(req *addSingleContributionMsg
 	ourKey := pendingReservation.partialState.OurMultiSigKey
 	theirKey := theirContribution.MultiSigKey
 	channelCapacity := int64(pendingReservation.partialState.Capacity)
-	redeemScript, _, err := genFundingPkScript(ourKey.PubKey().SerializeCompressed(),
+	redeemScript, _, err := GenFundingPkScript(ourKey.SerializeCompressed(),
 		theirKey.SerializeCompressed(), channelCapacity)
 	if err != nil {
 		req.err <- err
@@ -879,9 +831,15 @@ func (l *LightningWallet) handleSingleContribution(req *addSingleContributionMsg
 	}
 	pendingReservation.partialState.FundingRedeemScript = redeemScript
 
+	masterElkremRoot, err := l.deriveMasterElkremRoot()
+	if err != nil {
+		req.err <- err
+		return
+	}
+
 	// Now that we know their commitment key, we can create the revocation
 	// key for our version of the initial commitment transaction.
-	elkremRoot := deriveElkremRoot(ourKey, theirKey)
+	elkremRoot := deriveElkremRoot(masterElkremRoot, ourKey, theirKey)
 	elkremSender := elkrem.NewElkremSender(elkremRoot)
 	firstPreimage, err := elkremSender.AtIndex(0)
 	if err != nil {
@@ -890,7 +848,7 @@ func (l *LightningWallet) handleSingleContribution(req *addSingleContributionMsg
 	}
 	pendingReservation.partialState.LocalElkrem = elkremSender
 	theirCommitKey := theirContribution.CommitKey
-	ourRevokeKey := deriveRevocationPubkey(theirCommitKey, firstPreimage[:])
+	ourRevokeKey := DeriveRevocationPubkey(theirCommitKey, firstPreimage[:])
 
 	// Initialize an empty sha-chain for them, tracking the current pending
 	// revocation hash (we don't yet know the pre-image so we can't add it
@@ -951,25 +909,16 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 			// Fetch the alleged previous output along with the
 			// pkscript referenced by this input.
 			prevOut := txin.PreviousOutPoint
-			output, err := l.rpc.GetTxOut(&prevOut.Hash, prevOut.Index, false)
+			output, err := l.chainIO.GetUtxo(&prevOut.Hash, prevOut.Index)
 			if output == nil {
 				msg.err <- fmt.Errorf("input to funding tx does not exist: %v", err)
 				return
 			}
 
-			pkScript, err := hex.DecodeString(output.ScriptPubKey.Hex)
-			if err != nil {
-				msg.err <- err
-				return
-			}
-			// Sadly, gettxout returns the output value in BTC
-			// instead of satoshis.
-			inputValue := int64(output.Value) * 1e8
-
 			// Ensure that the witness+sigScript combo is valid.
-			vm, err := txscript.NewEngine(pkScript,
+			vm, err := txscript.NewEngine(output.PkScript,
 				fundingTx, i, txscript.StandardVerifyFlags, nil,
-				fundingHashCache, inputValue)
+				fundingHashCache, output.Value)
 			if err != nil {
 				// TODO(roasbeef): cancel at this stage if invalid sigs?
 				msg.err <- fmt.Errorf("cannot create script engine: %s", err)
@@ -989,54 +938,37 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 	pendingReservation.theirCommitmentSig = msg.theirCommitmentSig
 	commitTx := pendingReservation.partialState.OurCommitTx
 	theirKey := pendingReservation.theirContribution.MultiSigKey
-	ourKey := pendingReservation.partialState.OurMultiSigKey
 
 	// Re-generate both the redeemScript and p2sh output. We sign the
 	// redeemScript script, but include the p2sh output as the subscript
 	// for verification.
 	redeemScript := pendingReservation.partialState.FundingRedeemScript
-	p2wsh, err := witnessScriptHash(redeemScript)
-	if err != nil {
-		msg.err <- err
-		return
-	}
-
-	// First, we sign our copy of the commitment transaction ourselves.
-	channelValue := int64(pendingReservation.partialState.Capacity)
-	hashCache := txscript.NewTxSigHashes(commitTx)
-	ourCommitSig, err := txscript.RawTxInWitnessSignature(commitTx, hashCache, 0,
-		channelValue, redeemScript, txscript.SigHashAll, ourKey)
-	if err != nil {
-		msg.err <- err
-		return
-	}
 
 	// Next, create the spending scriptSig, and then verify that the script
 	// is complete, allowing us to spend from the funding transaction.
 	theirCommitSig := msg.theirCommitmentSig
-	ourKeySer := ourKey.PubKey().SerializeCompressed()
-	theirKeySer := theirKey.SerializeCompressed()
-	witness := spendMultiSig(redeemScript, ourKeySer, ourCommitSig,
-		theirKeySer, theirCommitSig)
-
-	// Finally, create an instance of a Script VM, and ensure that the
-	// Script executes succesfully.
-	commitTx.TxIn[0].Witness = witness
-	vm, err := txscript.NewEngine(p2wsh,
-		commitTx, 0, txscript.StandardVerifyFlags, nil,
-		nil, channelValue)
+	channelValue := int64(pendingReservation.partialState.Capacity)
+	hashCache := txscript.NewTxSigHashes(commitTx)
+	sigHash, err := txscript.CalcWitnessSigHash(redeemScript, hashCache,
+		txscript.SigHashAll, commitTx, 0, channelValue)
 	if err != nil {
-		msg.err <- err
-		return
-	}
-	if err := vm.Execute(); err != nil {
 		msg.err <- fmt.Errorf("counterparty's commitment signature is invalid: %v", err)
 		return
 	}
 
-	// Strip and store the signature to ensure that our commitment
-	// transaction doesn't stay hot.
-	commitTx.TxIn[0].Witness = nil
+	walletLog.Infof("sighash verify: %v", hex.EncodeToString(sigHash))
+	walletLog.Infof("initer verifying tx: %v", spew.Sdump(commitTx))
+
+	// Verify that we've received a valid signature from the remote party
+	// for our version of the commitment transaction.
+	sig, err := btcec.ParseSignature(theirCommitSig, btcec.S256())
+	if err != nil {
+		msg.err <- err
+		return
+	} else if !sig.Verify(sigHash, theirKey) {
+		msg.err <- fmt.Errorf("counterparty's commitment signature is invalid")
+		return
+	}
 	pendingReservation.partialState.OurCommitSig = theirCommitSig
 
 	// Funding complete, this entry can be removed from limbo.
@@ -1101,14 +1033,14 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 	theirCommitKey := pendingReservation.theirContribution.CommitKey
 	ourBalance := pendingReservation.ourContribution.FundingAmount
 	theirBalance := pendingReservation.theirContribution.FundingAmount
-	ourCommitTx, err := createCommitTx(fundingTxIn, ourCommitKey, theirCommitKey,
+	ourCommitTx, err := CreateCommitTx(fundingTxIn, ourCommitKey, theirCommitKey,
 		pendingReservation.ourContribution.RevocationKey,
 		pendingReservation.ourContribution.CsvDelay, ourBalance, theirBalance)
 	if err != nil {
 		req.err <- err
 		return
 	}
-	theirCommitTx, err := createCommitTx(fundingTxIn, theirCommitKey, ourCommitKey,
+	theirCommitTx, err := CreateCommitTx(fundingTxIn, theirCommitKey, ourCommitKey,
 		req.revokeKey, pendingReservation.theirContribution.CsvDelay,
 		theirBalance, ourBalance)
 	if err != nil {
@@ -1123,65 +1055,51 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 	pendingReservation.partialState.OurCommitTx = ourCommitTx
 	txsort.InPlaceSort(theirCommitTx)
 
-	// Verify that their signature of valid for our current commitment
-	// transaction. Re-generate both the redeemScript and p2sh output. We
-	// sign the redeemScript script, but include the p2sh output as the
-	// subscript for verification.
-	// TODO(roasbeef): replace with regular sighash calculation once the PR
-	// is merged.
 	redeemScript := pendingReservation.partialState.FundingRedeemScript
-	p2wsh, err := witnessScriptHash(redeemScript)
-	if err != nil {
-		req.err <- err
-		return
-	}
-	// TODO(roasbeef): remove all duplication after merge.
-
-	// First, we sign our copy of the commitment transaction ourselves.
 	channelValue := int64(pendingReservation.partialState.Capacity)
 	hashCache := txscript.NewTxSigHashes(ourCommitTx)
 	theirKey := pendingReservation.theirContribution.MultiSigKey
 	ourKey := pendingReservation.partialState.OurMultiSigKey
-	ourCommitSig, err := txscript.RawTxInWitnessSignature(ourCommitTx, hashCache, 0,
-		channelValue, redeemScript, txscript.SigHashAll, ourKey)
+
+	sigHash, err := txscript.CalcWitnessSigHash(redeemScript, hashCache,
+		txscript.SigHashAll, ourCommitTx, 0, channelValue)
 	if err != nil {
 		req.err <- err
 		return
 	}
 
-	// Next, create the spending scriptSig, and then verify that the script
-	// is complete, allowing us to spend from the funding transaction.
-	ourKeySer := ourKey.PubKey().SerializeCompressed()
-	theirKeySer := theirKey.SerializeCompressed()
-	witness := spendMultiSig(redeemScript, ourKeySer, ourCommitSig,
-		theirKeySer, req.theirCommitmentSig)
-
-	// Finally, create an instance of a Script VM, and ensure that the
-	// Script executes succesfully.
-	ourCommitTx.TxIn[0].Witness = witness
-	// TODO(roasbeef): replace engine with plain sighash check
-	vm, err := txscript.NewEngine(p2wsh, ourCommitTx, 0,
-		txscript.StandardVerifyFlags, nil, nil, channelValue)
+	// Verify that we've received a valid signature from the remote party
+	// for our version of the commitment transaction.
+	sig, err := btcec.ParseSignature(req.theirCommitmentSig, btcec.S256())
 	if err != nil {
 		req.err <- err
 		return
-	}
-	if err := vm.Execute(); err != nil {
-		req.err <- fmt.Errorf("counterparty's commitment signature is invalid: %v", err)
+	} else if !sig.Verify(sigHash, theirKey) {
+		req.err <- fmt.Errorf("counterparty's commitment signature is invalid")
 		return
 	}
-
-	// Strip and store the signature to ensure that our commitment
-	// transaction doesn't stay hot.
-	ourCommitTx.TxIn[0].Witness = nil
 	pendingReservation.partialState.OurCommitSig = req.theirCommitmentSig
 
 	// With their signature for our version of the commitment transactions
 	// verified, we can now generate a signature for their version,
 	// allowing the funding transaction to be safely broadcast.
-	hashCache = txscript.NewTxSigHashes(theirCommitTx)
-	sigTheirCommit, err := txscript.RawTxInWitnessSignature(theirCommitTx, hashCache, 0,
-		channelValue, redeemScript, txscript.SigHashAll, ourKey)
+	p2wsh, err := witnessScriptHash(redeemScript)
+	if err != nil {
+		req.err <- err
+		return
+	}
+	signDesc := SignDescriptor{
+		RedeemScript: redeemScript,
+		PubKey:       ourKey,
+		Output: &wire.TxOut{
+			PkScript: p2wsh,
+			Value:    channelValue,
+		},
+		HashType:   txscript.SigHashAll,
+		SigHashes:  txscript.NewTxSigHashes(theirCommitTx),
+		InputIndex: 0,
+	}
+	sigTheirCommit, err := l.Signer.SignOutputRaw(theirCommitTx, &signDesc)
 	if err != nil {
 		req.err <- err
 		return
@@ -1224,8 +1142,7 @@ func (l *LightningWallet) handleChannelOpen(req *channelOpenMsg) {
 
 	// Finally, create and officially open the payment channel!
 	// TODO(roasbeef): CreationTime once tx is 'open'
-	channel, _ := NewLightningChannel(l, l.chainNotifier, l.channelDB,
-		res.partialState)
+	channel, _ := NewLightningChannel(l.Signer, l, l.chainNotifier, res.partialState)
 
 	res.chanOpen <- channel
 	req.err <- nil
@@ -1266,68 +1183,18 @@ out:
 
 	// Finally, create and officially open the payment channel!
 	// TODO(roasbeef): CreationTime once tx is 'open'
-	channel, _ := NewLightningChannel(l, l.chainNotifier, l.channelDB,
+	channel, _ := NewLightningChannel(l.Signer, l, l.chainNotifier,
 		res.partialState)
 	res.chanOpen <- channel
 }
 
-// getNextRawKey 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.
-// TODO(roasbeef): on shutdown, write state of pending keys, then read back?
-func (l *LightningWallet) getNextRawKey() (*btcec.PrivateKey, error) {
-	l.KeyGenMtx.Lock()
-	defer l.KeyGenMtx.Unlock()
-
-	nextAddr, err := l.Manager.NextExternalAddresses(waddrmgr.DefaultAccountNum,
-		1, waddrmgr.WitnessPubKey)
-	if err != nil {
-		return nil, err
-	}
-
-	pkAddr := nextAddr[0].(waddrmgr.ManagedPubKeyAddress)
-
-	return pkAddr.PrivKey()
-}
-
-// ListUnspentWitness returns a slice of all the unspent outputs the wallet
-// controls which pay to witness programs either directly or indirectly.
-func (l *LightningWallet) ListUnspentWitness(minConfs int32) ([]*btcjson.ListUnspentResult, error) {
-	// First, grab all the unfiltered currently unspent outputs.
-	maxConfs := int32(math.MaxInt32)
-	unspentOutputs, err := l.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([]*btcjson.ListUnspentResult, 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) {
-			witnessOutputs = append(witnessOutputs, output)
-		}
-
-	}
-
-	return witnessOutputs, nil
-}
-
 // selectCoinsAndChange performs coin selection in order to obtain witness
 // outputs which sum to at least 'numCoins' amount of satoshis. If coin
 // selection is succesful/possible, then the selected coins are available within
 // the passed contribution's inputs. If necessary, a change address will also be
 // generated.
 // TODO(roasbeef): remove hardcoded fees and req'd confs for outputs.
-func (l *LightningWallet) selectCoinsAndChange(numCoins btcutil.Amount,
+func (l *LightningWallet) selectCoinsAndChange(feeRate uint64, amt btcutil.Amount,
 	contribution *ChannelContribution) error {
 
 	// We hold the coin select mutex while querying for outputs, and
@@ -1337,22 +1204,10 @@ func (l *LightningWallet) selectCoinsAndChange(numCoins btcutil.Amount,
 	// when we encounter an error condition.
 	l.coinSelectMtx.Lock()
 
-	// TODO(roasbeef): check if balance is insufficient, if so then select
-	// on two channels, one is a time.After that will bail out with
-	// insuffcient funds, the other is a notification that the balance has
-	// been updated make(chan struct{}, 1).
-
 	// Find all unlocked unspent witness outputs with greater than 1
 	// confirmation.
 	// TODO(roasbeef): make num confs a configuration paramter
-	unspentOutputs, err := l.ListUnspentWitness(1)
-	if err != nil {
-		l.coinSelectMtx.Unlock()
-		return err
-	}
-
-	// Convert the outputs to coins for coin selection below.
-	coins, err := outputsToCoins(unspentOutputs)
+	coins, err := l.ListUnspentWitness(1)
 	if err != nil {
 		l.coinSelectMtx.Unlock()
 		return err
@@ -1360,17 +1215,8 @@ func (l *LightningWallet) selectCoinsAndChange(numCoins btcutil.Amount,
 
 	// Peform coin selection over our available, unlocked unspent outputs
 	// in order to find enough coins to meet the funding amount requirements.
-	//
-	// TODO(roasbeef): Should extend coinset with optimal coin selection
-	// heuristics for our use case.
-	// NOTE: this current selection assumes "priority" is still a thing.
-	selector := &coinset.MaxValueAgeCoinSelector{
-		MaxInputs:       10,
-		MinChangeAmount: 10000,
-	}
-	// TODO(roasbeef): don't hardcode fee...
-	totalWithFee := numCoins + 10000
-	selectedCoins, err := selector.CoinSelect(totalWithFee, coins)
+	// TODO(roasbeef): take in sat/byte
+	selectedCoins, changeAmt, err := coinSelect(feeRate, amt, coins)
 	if err != nil {
 		l.coinSelectMtx.Unlock()
 		return err
@@ -1379,57 +1225,151 @@ func (l *LightningWallet) selectCoinsAndChange(numCoins btcutil.Amount,
 	// Lock the selected coins. These coins are now "reserved", this
 	// prevents concurrent funding requests from referring to and this
 	// double-spending the same set of coins.
-	contribution.Inputs = make([]*wire.TxIn, len(selectedCoins.Coins()))
-	for i, coin := range selectedCoins.Coins() {
-		txout := wire.NewOutPoint(coin.Hash(), coin.Index())
-		l.LockOutpoint(*txout)
+	contribution.Inputs = make([]*wire.TxIn, len(selectedCoins))
+	for i, coin := range selectedCoins {
+		l.lockedOutPoints[*coin] = struct{}{}
+		l.LockOutpoint(*coin)
 
 		// Empty sig script, we'll actually sign if this reservation is
 		// queued up to be completed (the other side accepts).
-		outPoint := wire.NewOutPoint(coin.Hash(), coin.Index())
-		contribution.Inputs[i] = wire.NewTxIn(outPoint, nil, nil)
+		contribution.Inputs[i] = wire.NewTxIn(coin, nil, nil)
+	}
+
+	// Record any change output(s) generated as a result of the coin
+	// selection.
+	if changeAmt != 0 {
+		changeAddr, err := l.NewAddress(WitnessPubKey, true)
+		if err != nil {
+			return err
+		}
+		changeScript, err := txscript.PayToAddrScript(changeAddr)
+		if err != nil {
+			return err
+		}
+
+		contribution.ChangeOutputs = make([]*wire.TxOut, 1)
+		contribution.ChangeOutputs[0] = &wire.TxOut{
+			Value:    int64(changeAmt),
+			PkScript: changeScript,
+		}
 	}
 
 	l.coinSelectMtx.Unlock()
 
-	// Create some possibly neccessary change outputs.
-	selectedTotalValue := coinset.NewCoinSet(selectedCoins.Coins()).TotalValue()
-	if selectedTotalValue > totalWithFee {
-		// Change is necessary. Query for an available change address to
-		// send the remainder to.
-		contribution.ChangeOutputs = make([]*wire.TxOut, 1)
-		changeAddr, err := l.NewChangeAddress(waddrmgr.DefaultAccountNum,
-			waddrmgr.WitnessPubKey)
-		if err != nil {
-			return err
-		}
-
-		changeAddrScript, err := txscript.PayToAddrScript(changeAddr)
-		if err != nil {
-			return err
-		}
-
-		changeAmount := selectedTotalValue - totalWithFee
-		contribution.ChangeOutputs[0] = wire.NewTxOut(int64(changeAmount),
-			changeAddrScript)
-	}
-
-	// TODO(roasbeef): re-calculate fees here to minFeePerKB, may need more inputs
 	return nil
 }
 
-type WaddrmgrEncryptorDecryptor struct {
-	M *waddrmgr.Manager
+// deriveMasterElkremRoot derives the private key which serves as the master
+// elkrem root. This master secret is used as the secret input to a HKDF to
+// generate elkrem secrets based on random, but public data.
+func (l *LightningWallet) deriveMasterElkremRoot() (*btcec.PrivateKey, error) {
+	masterElkremRoot, err := l.rootKey.Child(elkremRootIndex)
+	if err != nil {
+		return nil, err
+	}
+
+	return masterElkremRoot.ECPrivKey()
 }
 
-func (w *WaddrmgrEncryptorDecryptor) Encrypt(p []byte) ([]byte, error) {
-	return w.M.Encrypt(waddrmgr.CKTPrivate, p)
+// selectInputs selects a slice of inputs necessary to meet the specified
+// selection amount. If input selectino is unable to suceed to to insuffcient
+// funds, a non-nil error is returned. Additionally, the total amount of the
+// selected coins are returned in order for the caller to properly handle
+// change+fees.
+func selectInputs(amt btcutil.Amount, coins []*Utxo) (btcutil.Amount, []*wire.OutPoint, error) {
+	var (
+		selectedUtxos []*wire.OutPoint
+		satSelected   btcutil.Amount
+	)
+
+	i := 0
+	for satSelected < amt {
+		// If we're about to go past the number of available coins,
+		// then exit with an error.
+		if i > len(coins)-1 {
+			return 0, nil, ErrInsufficientFunds
+		}
+
+		// Otherwise, collect this new coin as it may be used for final
+		// coin selection.
+		coin := coins[i]
+		utxo := &wire.OutPoint{
+			Hash:  coin.Hash,
+			Index: coin.Index,
+		}
+
+		selectedUtxos = append(selectedUtxos, utxo)
+		satSelected += coin.Value
+
+		i++
+	}
+
+	return satSelected, selectedUtxos, nil
 }
 
-func (w *WaddrmgrEncryptorDecryptor) Decrypt(c []byte) ([]byte, error) {
-	return w.M.Decrypt(waddrmgr.CKTPrivate, c)
-}
+// coinSelect attemps to select a sufficient amount of coins, including a
+// change output to fund amt satoshis, adhearing to the specified fee rate. The
+// specified fee rate should be expressed in sat/byte for coin selection to
+// function properly.
+func coinSelect(feeRate uint64, amt btcutil.Amount,
+	coins []*Utxo) ([]*wire.OutPoint, btcutil.Amount, error) {
 
-func (w *WaddrmgrEncryptorDecryptor) OverheadSize() uint32 {
-	return 24
+	const (
+		// txOverhead is the overhead of a transaction residing within
+		// the version number and lock time.
+		txOverhead = 8
+
+		// p2wkhSpendSize an estimate of the number of bytes it takes
+		// to spend a p2wkh output.
+		//
+		// (p2wkh witness) + txid + index + varint script size + sequence
+		// TODO(roasbeef): div by 3 due to witness size?
+		p2wkhSpendSize = (1 + 73 + 1 + 33) + 32 + 4 + 1 + 4
+
+		// p2wkhOutputSize is an estimate of the size of a regualr
+		// p2wkh output.
+		//
+		// 8 (output) + 1 (var int script) + 22 (p2wkh output)
+		p2wkhOutputSize = 8 + 1 + 22
+
+		// p2wkhOutputSize is an estimate of the p2wsh funding uotput.
+		p2wshOutputSize = 8 + 1 + 34
+	)
+
+	var estimatedSize int
+
+	amtNeeded := amt
+	for {
+		// First perform an initial round of coin selection to estimate
+		// the required fee.
+		totalSat, selectedUtxos, err := selectInputs(amtNeeded, coins)
+		if err != nil {
+			return nil, 0, err
+		}
+
+		// Based on the selected coins, estimate the size of the final
+		// fully signed transaction.
+		estimatedSize = ((len(selectedUtxos) * p2wkhSpendSize) +
+			p2wshOutputSize + txOverhead)
+
+		// The difference bteween the selected amount and the amount
+		// requested will be used to pay fees, and generate a change
+		// output with the remaining.
+		overShootAmt := totalSat - amtNeeded
+
+		// Based on the estimated size and fee rate, if the excess
+		// amount isn't enough to pay fees, then increase the requested
+		// coin amount by the estimate required fee, performing another
+		// round of coin selection.
+		requiredFee := btcutil.Amount(uint64(estimatedSize) * feeRate)
+		if overShootAmt < requiredFee {
+			amtNeeded += requiredFee
+			continue
+		}
+
+		// If the fee is sufficient, then calculate the size of the change output.
+		changeAmt := overShootAmt - requiredFee
+
+		return selectedUtxos, changeAmt, nil
+	}
 }

peer.go

@@ -218,8 +218,8 @@ func newPeer(conn net.Conn, server *server, btcNet wire.BitcoinNet, inbound bool
 func (p *peer) loadActiveChannels(chans []*channeldb.OpenChannel) error {
 	for _, dbChan := range chans {
 		chanID := dbChan.ChanID
-		lnChan, err := lnwallet.NewLightningChannel(p.server.lnwallet,
-			p.server.chainNotifier, p.server.chanDB, dbChan)
+		lnChan, err := lnwallet.NewLightningChannel(p.server.lnwallet.Signer,
+			p.server.lnwallet, p.server.chainNotifier, dbChan)
 		if err != nil {
 			return err
 		}

rpcserver.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/lightningnetwork/lnd/lndc"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/roasbeef/btcd/txscript"
 	"github.com/roasbeef/btcd/wire"
@@ -96,7 +97,7 @@ func (r *rpcServer) sendCoinsOnChain(paymentMap map[string]int64) (*wire.ShaHash
 		return nil, err
 	}
 
-	return r.server.lnwallet.SendOutputs(outputs, defaultAccount, 1)
+	return r.server.lnwallet.SendOutputs(outputs)
 }
 
 // SendCoins executes a request to send coins to a particular address. Unlike
@@ -136,23 +137,19 @@ func (r *rpcServer) SendMany(ctx context.Context,
 func (r *rpcServer) NewAddress(ctx context.Context,
 	in *lnrpc.NewAddressRequest) (*lnrpc.NewAddressResponse, error) {
 
-	r.server.lnwallet.KeyGenMtx.Lock()
-	defer r.server.lnwallet.KeyGenMtx.Unlock()
-
 	// Translate the gRPC proto address type to the wallet controller's
 	// available address types.
-	var addrType waddrmgr.AddressType
+	var addrType lnwallet.AddressType
 	switch in.Type {
 	case lnrpc.NewAddressRequest_WITNESS_PUBKEY_HASH:
-		addrType = waddrmgr.WitnessPubKey
+		addrType = lnwallet.WitnessPubKey
 	case lnrpc.NewAddressRequest_NESTED_PUBKEY_HASH:
-		addrType = waddrmgr.NestedWitnessPubKey
+		addrType = lnwallet.NestedWitnessPubKey
 	case lnrpc.NewAddressRequest_PUBKEY_HASH:
-		addrType = waddrmgr.PubKeyHash
+		addrType = lnwallet.PubKeyHash
 	}
 
-	addr, err := r.server.lnwallet.NewAddress(defaultAccount,
-		addrType)
+	addr, err := r.server.lnwallet.NewAddress(addrType, false)
 	if err != nil {
 		return nil, err
 	}
@@ -378,35 +375,14 @@ func (r *rpcServer) ListPeers(ctx context.Context,
 func (r *rpcServer) WalletBalance(ctx context.Context,
 	in *lnrpc.WalletBalanceRequest) (*lnrpc.WalletBalanceResponse, error) {
 
-	var balance float64
-
-	if in.WitnessOnly {
-		witnessOutputs, err := r.server.lnwallet.ListUnspentWitness(1)
-		if err != nil {
-			return nil, err
-		}
-
-		// We need to convert from BTC to satoshi here otherwise, and
-		// incorrect sum will be returned.
-		var outputSum btcutil.Amount
-		for _, witnessOutput := range witnessOutputs {
-			outputSum += btcutil.Amount(witnessOutput.Amount * 1e8)
-		}
-
-		balance = outputSum.ToBTC()
-	} else {
-		// TODO(roasbeef): make num confs a param
-		outputSum, err := r.server.lnwallet.CalculateBalance(1)
-		if err != nil {
-			return nil, err
-		}
-
-		balance = outputSum.ToBTC()
+	balance, err := r.server.lnwallet.ConfirmedBalance(1, in.WitnessOnly)
+	if err != nil {
+		return nil, err
 	}
 
 	rpcsLog.Debugf("[walletbalance] balance=%v", balance)
 
-	return &lnrpc.WalletBalanceResponse{balance}, nil
+	return &lnrpc.WalletBalanceResponse{balance.ToBTC()}, nil
 }
 
 // PendingChannels returns a list of all the channels that are currently

server.go

@@ -18,7 +18,6 @@ import (
 
 	"github.com/BitfuryLightning/tools/routing"
 	"github.com/BitfuryLightning/tools/rt/graph"
-	"github.com/roasbeef/btcwallet/waddrmgr"
 )
 
 // server is the main server of the Lightning Network Daemon. The server
@@ -66,7 +65,7 @@ type server struct {
 func newServer(listenAddrs []string, notifier chainntnfs.ChainNotifier,
 	wallet *lnwallet.LightningWallet, chanDB *channeldb.DB) (*server, error) {
 
-	privKey, err := getIdentityPrivKey(chanDB, wallet)
+	privKey, err := wallet.GetIdentitykey()
 	if err != nil {
 		return nil, err
 	}
@@ -493,33 +492,3 @@ func (s *server) listener(l net.Listener) {
 
 	s.wg.Done()
 }
-
-// getIdentityPrivKey gets the identity private key out of the wallet DB.
-func getIdentityPrivKey(c *channeldb.DB,
-	w *lnwallet.LightningWallet) (*btcec.PrivateKey, error) {
-
-	// First retrieve the current identity address for this peer.
-	adr, err := c.GetIdAdr()
-	if err != nil {
-		return nil, err
-	}
-
-	// Using the ID address, request the private key coresponding to the
-	// address from the wallet's address manager.
-	adr2, err := w.Manager.Address(adr)
-	if err != nil {
-		return nil, err
-	}
-
-	serializedKey := adr2.(waddrmgr.ManagedPubKeyAddress).PubKey().SerializeCompressed()
-	keyEncoded := hex.EncodeToString(serializedKey)
-	ltndLog.Infof("identity address: %v", adr)
-	ltndLog.Infof("identity pubkey retrieved: %v", keyEncoded)
-
-	priv, err := adr2.(waddrmgr.ManagedPubKeyAddress).PrivKey()
-	if err != nil {
-		return nil, err
-	}
-
-	return priv, nil
-}