Merge pull request #2481 from joostjager/move-input

multi: move input to separate package

lnwallet/btcwallet/signer.go

@@ -10,6 +10,7 @@ import (
 	base "github.com/btcsuite/btcwallet/wallet"
 	"github.com/btcsuite/btcwallet/walletdb"
 	"github.com/go-errors/errors"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
@@ -132,18 +133,18 @@ func (b *BtcWallet) fetchPrivKey(keyDesc *keychain.KeyDescriptor) (*btcec.Privat
 // maybeTweakPrivKey examines the single and double tweak parameters on the
 // passed sign descriptor and may perform a mapping on the passed private key
 // in order to utilize the tweaks, if populated.
-func maybeTweakPrivKey(signDesc *lnwallet.SignDescriptor,
+func maybeTweakPrivKey(signDesc *input.SignDescriptor,
 	privKey *btcec.PrivateKey) (*btcec.PrivateKey, error) {
 
 	var retPriv *btcec.PrivateKey
 	switch {
 
 	case signDesc.SingleTweak != nil:
-		retPriv = lnwallet.TweakPrivKey(privKey,
+		retPriv = input.TweakPrivKey(privKey,
 			signDesc.SingleTweak)
 
 	case signDesc.DoubleTweak != nil:
-		retPriv = lnwallet.DeriveRevocationPrivKey(privKey,
+		retPriv = input.DeriveRevocationPrivKey(privKey,
 			signDesc.DoubleTweak)
 
 	default:
@@ -158,7 +159,7 @@ func maybeTweakPrivKey(signDesc *lnwallet.SignDescriptor,
 //
 // This is a part of the WalletController interface.
 func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+	signDesc *input.SignDescriptor) ([]byte, error) {
 
 	witnessScript := signDesc.WitnessScript
 
@@ -199,7 +200,7 @@ func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx,
 //
 // This is a part of the WalletController interface.
 func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+	signDesc *input.SignDescriptor) (*input.Script, error) {
 
 	outputScript := signDesc.Output.PkScript
 	walletAddr, err := b.fetchOutputAddr(outputScript)
@@ -214,7 +215,7 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
 	}
 
 	var witnessProgram []byte
-	inputScript := &lnwallet.InputScript{}
+	inputScript := &input.Script{}
 
 	switch {
 
@@ -282,7 +283,7 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
 
 // A compile time check to ensure that BtcWallet implements the Signer
 // interface.
-var _ lnwallet.Signer = (*BtcWallet)(nil)
+var _ input.Signer = (*BtcWallet)(nil)
 
 // SignMessage attempts to sign a target message with the private key that
 // corresponds to the passed public key. If the target private key is unable to

lnwallet/channel.go

@@ -9,17 +9,18 @@ import (
 	"sync"
 
 	"github.com/btcsuite/btcd/blockchain"
-	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/davecgh/go-spew/spew"
-	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/lnwire"
-
 	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcutil/txsort"
+	"github.com/davecgh/go-spew/spew"
+
+	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
+	"github.com/lightningnetwork/lnd/lnwire"
 )
 
 var zeroHash chainhash.Hash
@@ -967,16 +968,16 @@ func deriveCommitmentKeys(commitPoint *btcec.PublicKey, isOurCommit bool,
 	keyRing := &CommitmentKeyRing{
 		CommitPoint: commitPoint,
 
-		LocalCommitKeyTweak: SingleTweakBytes(
+		LocalCommitKeyTweak: input.SingleTweakBytes(
 			commitPoint, localChanCfg.PaymentBasePoint.PubKey,
 		),
-		LocalHtlcKeyTweak: SingleTweakBytes(
+		LocalHtlcKeyTweak: input.SingleTweakBytes(
 			commitPoint, localChanCfg.HtlcBasePoint.PubKey,
 		),
-		LocalHtlcKey: TweakPubKey(
+		LocalHtlcKey: input.TweakPubKey(
 			localChanCfg.HtlcBasePoint.PubKey, commitPoint,
 		),
-		RemoteHtlcKey: TweakPubKey(
+		RemoteHtlcKey: input.TweakPubKey(
 			remoteChanCfg.HtlcBasePoint.PubKey, commitPoint,
 		),
 	}
@@ -1003,9 +1004,9 @@ func deriveCommitmentKeys(commitPoint *btcec.PublicKey, isOurCommit bool,
 
 	// With the base points assigned, we can now derive the actual keys
 	// using the base point, and the current commitment tweak.
-	keyRing.DelayKey = TweakPubKey(delayBasePoint, commitPoint)
-	keyRing.NoDelayKey = TweakPubKey(noDelayBasePoint, commitPoint)
-	keyRing.RevocationKey = DeriveRevocationPubkey(
+	keyRing.DelayKey = input.TweakPubKey(delayBasePoint, commitPoint)
+	keyRing.NoDelayKey = input.TweakPubKey(noDelayBasePoint, commitPoint)
+	keyRing.RevocationKey = input.DeriveRevocationPubkey(
 		revocationBasePoint, commitPoint,
 	)
 
@@ -1285,11 +1286,11 @@ type LightningChannel struct {
 	// Signer is the main signer instances that will be responsible for
 	// signing any HTLC and commitment transaction generated by the state
 	// machine.
-	Signer Signer
+	Signer input.Signer
 
 	// signDesc is the primary sign descriptor that is capable of signing
 	// the commitment transaction that spends the multi-sig output.
-	signDesc *SignDescriptor
+	signDesc *input.SignDescriptor
 
 	channelEvents chainntnfs.ChainNotifier
 
@@ -1363,7 +1364,7 @@ type LightningChannel struct {
 // settled channel state. Throughout state transitions, then channel will
 // automatically persist pertinent state to the database in an efficient
 // manner.
-func NewLightningChannel(signer Signer, pCache PreimageCache,
+func NewLightningChannel(signer input.Signer, pCache PreimageCache,
 	state *channeldb.OpenChannel,
 	sigPool *SigPool) (*LightningChannel, error) {
 
@@ -1423,16 +1424,16 @@ func (lc *LightningChannel) createSignDesc() error {
 	localKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	remoteKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 
-	multiSigScript, err := GenMultiSigScript(localKey, remoteKey)
+	multiSigScript, err := input.GenMultiSigScript(localKey, remoteKey)
 	if err != nil {
 		return err
 	}
 
-	fundingPkScript, err := WitnessScriptHash(multiSigScript)
+	fundingPkScript, err := input.WitnessScriptHash(multiSigScript)
 	if err != nil {
 		return err
 	}
-	lc.signDesc = &SignDescriptor{
+	lc.signDesc = &input.SignDescriptor{
 		KeyDesc:       lc.localChanCfg.MultiSigKey,
 		WitnessScript: multiSigScript,
 		Output: &wire.TxOut{
@@ -1616,7 +1617,7 @@ func (lc *LightningChannel) restoreCommitState(
 	if err != nil {
 		return err
 	}
-	localCommitPoint := ComputeCommitmentPoint(ourRevPreImage[:])
+	localCommitPoint := input.ComputeCommitmentPoint(ourRevPreImage[:])
 	remoteCommitPoint := lc.channelState.RemoteCurrentRevocation
 
 	// With the revocation state reconstructed, we can now convert the disk
@@ -1859,7 +1860,7 @@ type HtlcRetribution struct {
 	// SignDesc is a design descriptor capable of generating the necessary
 	// signatures to satisfy the revocation clause of the HTLC's public key
 	// script.
-	SignDesc SignDescriptor
+	SignDesc input.SignDescriptor
 
 	// OutPoint is the target outpoint of this HTLC pointing to the
 	// breached commitment transaction.
@@ -1915,7 +1916,7 @@ type BreachRetribution struct {
 	//
 	// NOTE: A nil value indicates that the local output is considered dust
 	// according to the remote party's dust limit.
-	LocalOutputSignDesc *SignDescriptor
+	LocalOutputSignDesc *input.SignDescriptor
 
 	// LocalOutpoint is the outpoint of the output paying to us (the local
 	// party) within the breach transaction.
@@ -1928,7 +1929,7 @@ type BreachRetribution struct {
 	//
 	// NOTE: A nil value indicates that the local output is considered dust
 	// according to the remote party's dust limit.
-	RemoteOutputSignDesc *SignDescriptor
+	RemoteOutputSignDesc *input.SignDescriptor
 
 	// RemoteOutpoint is the outpoint of the output paying to the remote
 	// party within the breach transaction.
@@ -1983,17 +1984,17 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// number so we can have the proper witness script to sign and include
 	// within the final witness.
 	remoteDelay := uint32(chanState.RemoteChanCfg.CsvDelay)
-	remotePkScript, err := CommitScriptToSelf(
+	remotePkScript, err := input.CommitScriptToSelf(
 		remoteDelay, keyRing.DelayKey, keyRing.RevocationKey,
 	)
 	if err != nil {
 		return nil, err
 	}
-	remoteWitnessHash, err := WitnessScriptHash(remotePkScript)
+	remoteWitnessHash, err := input.WitnessScriptHash(remotePkScript)
 	if err != nil {
 		return nil, err
 	}
-	localPkScript, err := CommitScriptUnencumbered(keyRing.NoDelayKey)
+	localPkScript, err := input.CommitScriptUnencumbered(keyRing.NoDelayKey)
 	if err != nil {
 		return nil, err
 	}
@@ -2019,8 +2020,8 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// commitment outputs. If either is considered dust using the remote
 	// party's dust limit, the respective sign descriptor will be nil.
 	var (
-		localSignDesc  *SignDescriptor
-		remoteSignDesc *SignDescriptor
+		localSignDesc  *input.SignDescriptor
+		remoteSignDesc *input.SignDescriptor
 	)
 
 	// Compute the local and remote balances in satoshis.
@@ -2030,7 +2031,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// If the local balance exceeds the remote party's dust limit,
 	// instantiate the local sign descriptor.
 	if localAmt >= chanState.RemoteChanCfg.DustLimit {
-		localSignDesc = &SignDescriptor{
+		localSignDesc = &input.SignDescriptor{
 			SingleTweak:   keyRing.LocalCommitKeyTweak,
 			KeyDesc:       chanState.LocalChanCfg.PaymentBasePoint,
 			WitnessScript: localPkScript,
@@ -2045,7 +2046,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// Similarly, if the remote balance exceeds the remote party's dust
 	// limit, assemble the remote sign descriptor.
 	if remoteAmt >= chanState.RemoteChanCfg.DustLimit {
-		remoteSignDesc = &SignDescriptor{
+		remoteSignDesc = &input.SignDescriptor{
 			KeyDesc:       chanState.LocalChanCfg.RevocationBasePoint,
 			DoubleTweak:   commitmentSecret,
 			WitnessScript: remotePkScript,
@@ -2081,7 +2082,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 		// as we'll need it if we're revoking an HTLC output on the
 		// remote commitment transaction, and *they* go to the second
 		// level.
-		secondLevelWitnessScript, err := secondLevelHtlcScript(
+		secondLevelWitnessScript, err := input.SecondLevelHtlcScript(
 			keyRing.RevocationKey, keyRing.DelayKey, remoteDelay,
 		)
 		if err != nil {
@@ -2092,7 +2093,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 		// the sender of the HTLC (relative to us). So we'll
 		// re-generate the sender HTLC script.
 		if htlc.Incoming {
-			htlcWitnessScript, err = senderHTLCScript(
+			htlcWitnessScript, err = input.SenderHTLCScript(
 				keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 				keyRing.RevocationKey, htlc.RHash[:],
 			)
@@ -2104,7 +2105,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 			// Otherwise, is this was an outgoing HTLC that we
 			// sent, then from the PoV of the remote commitment
 			// state, they're the receiver of this HTLC.
-			htlcWitnessScript, err = receiverHTLCScript(
+			htlcWitnessScript, err = input.ReceiverHTLCScript(
 				htlc.RefundTimeout, keyRing.LocalHtlcKey,
 				keyRing.RemoteHtlcKey, keyRing.RevocationKey,
 				htlc.RHash[:],
@@ -2114,13 +2115,13 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 			}
 		}
 
-		htlcPkScript, err := WitnessScriptHash(htlcWitnessScript)
+		htlcPkScript, err := input.WitnessScriptHash(htlcWitnessScript)
 		if err != nil {
 			return nil, err
 		}
 
 		htlcRetributions = append(htlcRetributions, HtlcRetribution{
-			SignDesc: SignDescriptor{
+			SignDesc: input.SignDescriptor{
 				KeyDesc:       chanState.LocalChanCfg.RevocationBasePoint,
 				DoubleTweak:   commitmentSecret,
 				WitnessScript: htlcWitnessScript,
@@ -2161,13 +2162,13 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 // htlcTimeoutFee returns the fee in satoshis required for an HTLC timeout
 // transaction based on the current fee rate.
 func htlcTimeoutFee(feePerKw SatPerKWeight) btcutil.Amount {
-	return feePerKw.FeeForWeight(HtlcTimeoutWeight)
+	return feePerKw.FeeForWeight(input.HtlcTimeoutWeight)
 }
 
 // htlcSuccessFee returns the fee in satoshis required for an HTLC success
 // transaction based on the current fee rate.
 func htlcSuccessFee(feePerKw SatPerKWeight) btcutil.Amount {
-	return feePerKw.FeeForWeight(HtlcSuccessWeight)
+	return feePerKw.FeeForWeight(input.HtlcSuccessWeight)
 }
 
 // htlcIsDust determines if an HTLC output is dust or not depending on two
@@ -2364,7 +2365,7 @@ func (lc *LightningChannel) createCommitmentTx(c *commitment,
 	// on its total weight. Once we have the total weight, we'll multiply
 	// by the current fee-per-kw, then divide by 1000 to get the proper
 	// fee.
-	totalCommitWeight := CommitWeight + (HtlcWeight * numHTLCs)
+	totalCommitWeight := input.CommitWeight + (input.HtlcWeight * numHTLCs)
 
 	// With the weight known, we can now calculate the commitment fee,
 	// ensuring that we account for any dust outputs trimmed above.
@@ -2813,7 +2814,7 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 		// Finally, we'll generate a sign descriptor to generate a
 		// signature to give to the remote party for this commitment
 		// transaction. Note we use the raw HTLC amount.
-		sigJob.SignDesc = SignDescriptor{
+		sigJob.SignDesc = input.SignDescriptor{
 			KeyDesc:       localChanCfg.HtlcBasePoint,
 			SingleTweak:   keyRing.LocalHtlcKeyTweak,
 			WitnessScript: htlc.theirWitnessScript,
@@ -2864,7 +2865,7 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 		// Finally, we'll generate a sign descriptor to generate a
 		// signature to give to the remote party for this commitment
 		// transaction. Note we use the raw HTLC amount.
-		sigJob.SignDesc = SignDescriptor{
+		sigJob.SignDesc = input.SignDescriptor{
 			KeyDesc:       localChanCfg.HtlcBasePoint,
 			SingleTweak:   keyRing.LocalHtlcKeyTweak,
 			WitnessScript: htlc.theirWitnessScript,
@@ -3559,7 +3560,7 @@ func ChanSyncMsg(c *channeldb.OpenChannel) (*lnwire.ChannelReestablish, error) {
 		NextLocalCommitHeight:  nextLocalCommitHeight,
 		RemoteCommitTailHeight: remoteChainTipHeight,
 		LastRemoteCommitSecret: lastCommitSecret,
-		LocalUnrevokedCommitPoint: ComputeCommitmentPoint(
+		LocalUnrevokedCommitPoint: input.ComputeCommitmentPoint(
 			currentCommitSecret[:],
 		),
 	}, nil
@@ -3627,7 +3628,7 @@ func (lc *LightningChannel) computeView(view *htlcView, remoteChain bool,
 			continue
 		}
 
-		totalHtlcWeight += HtlcWeight
+		totalHtlcWeight += input.HtlcWeight
 	}
 	for _, htlc := range filteredHTLCView.theirUpdates {
 		if htlcIsDust(!remoteChain, !remoteChain, feePerKw,
@@ -3635,10 +3636,10 @@ func (lc *LightningChannel) computeView(view *htlcView, remoteChain bool,
 			continue
 		}
 
-		totalHtlcWeight += HtlcWeight
+		totalHtlcWeight += input.HtlcWeight
 	}
 
-	totalCommitWeight := CommitWeight + totalHtlcWeight
+	totalCommitWeight := input.CommitWeight + totalHtlcWeight
 	return ourBalance, theirBalance, totalCommitWeight, filteredHTLCView
 }
 
@@ -4031,7 +4032,7 @@ func (lc *LightningChannel) ReceiveNewCommitment(commitSig lnwire.Sig,
 	if err != nil {
 		return err
 	}
-	commitPoint := ComputeCommitmentPoint(commitSecret[:])
+	commitPoint := input.ComputeCommitmentPoint(commitSecret[:])
 	keyRing := deriveCommitmentKeys(commitPoint, true, lc.localChanCfg,
 		lc.remoteChanCfg)
 
@@ -4258,7 +4259,7 @@ func (lc *LightningChannel) ReceiveRevocation(revMsg *lnwire.RevokeAndAck) (
 	// revealed secret to derive a revocation key with our revocation base
 	// point, then it matches the current revocation of the remote party.
 	currentCommitPoint := lc.channelState.RemoteCurrentRevocation
-	derivedCommitPoint := ComputeCommitmentPoint(revMsg.Revocation[:])
+	derivedCommitPoint := input.ComputeCommitmentPoint(revMsg.Revocation[:])
 	if !derivedCommitPoint.IsEqual(currentCommitPoint) {
 		return nil, nil, nil, fmt.Errorf("revocation key mismatch")
 	}
@@ -4496,7 +4497,7 @@ func (lc *LightningChannel) NextRevocationKey() (*btcec.PublicKey, error) {
 		return nil, err
 	}
 
-	return ComputeCommitmentPoint(revocation[:]), nil
+	return input.ComputeCommitmentPoint(revocation[:]), nil
 }
 
 // InitNextRevocation inserts the passed commitment point as the _next_
@@ -4872,7 +4873,7 @@ func genHtlcScript(isIncoming, ourCommit bool, timeout uint32, rHash [32]byte,
 	// transaction. So we need to use the receiver's version of HTLC the
 	// script.
 	case isIncoming && ourCommit:
-		witnessScript, err = receiverHTLCScript(timeout,
+		witnessScript, err = input.ReceiverHTLCScript(timeout,
 			keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 			keyRing.RevocationKey, rHash[:])
 
@@ -4880,21 +4881,21 @@ func genHtlcScript(isIncoming, ourCommit bool, timeout uint32, rHash [32]byte,
 	// being added to their commitment transaction, so we use the sender's
 	// version of the HTLC script.
 	case isIncoming && !ourCommit:
-		witnessScript, err = senderHTLCScript(keyRing.RemoteHtlcKey,
+		witnessScript, err = input.SenderHTLCScript(keyRing.RemoteHtlcKey,
 			keyRing.LocalHtlcKey, keyRing.RevocationKey, rHash[:])
 
 	// We're sending an HTLC which is being added to our commitment
 	// transaction. Therefore, we need to use the sender's version of the
 	// HTLC script.
 	case !isIncoming && ourCommit:
-		witnessScript, err = senderHTLCScript(keyRing.LocalHtlcKey,
+		witnessScript, err = input.SenderHTLCScript(keyRing.LocalHtlcKey,
 			keyRing.RemoteHtlcKey, keyRing.RevocationKey, rHash[:])
 
 	// Finally, we're paying the remote party via an HTLC, which is being
 	// added to their commitment transaction. Therefore, we use the
 	// receiver's version of the HTLC script.
 	case !isIncoming && !ourCommit:
-		witnessScript, err = receiverHTLCScript(timeout, keyRing.LocalHtlcKey,
+		witnessScript, err = input.ReceiverHTLCScript(timeout, keyRing.LocalHtlcKey,
 			keyRing.RemoteHtlcKey, keyRing.RevocationKey, rHash[:])
 	}
 	if err != nil {
@@ -4903,7 +4904,7 @@ func genHtlcScript(isIncoming, ourCommit bool, timeout uint32, rHash [32]byte,
 
 	// Now that we have the redeem scripts, create the P2WSH public key
 	// script for the output itself.
-	htlcP2WSH, err := WitnessScriptHash(witnessScript)
+	htlcP2WSH, err := input.WitnessScriptHash(witnessScript)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -4972,7 +4973,7 @@ func (lc *LightningChannel) getSignedCommitTx() (*wire.MsgTx, error) {
 	ourKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	theirKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 
-	commitTx.TxIn[0].Witness = SpendMultiSig(
+	commitTx.TxIn[0].Witness = input.SpendMultiSig(
 		lc.signDesc.WitnessScript, ourKey,
 		ourSig, theirKey, theirSig,
 	)
@@ -4990,7 +4991,7 @@ type CommitOutputResolution struct {
 
 	// SelfOutputSignDesc is a fully populated sign descriptor capable of
 	// generating a valid signature to sweep the output paying to us.
-	SelfOutputSignDesc SignDescriptor
+	SelfOutputSignDesc input.SignDescriptor
 
 	// MaturityDelay is the relative time-lock, in blocks for all outputs
 	// that pay to the local party within the broadcast commitment
@@ -5046,7 +5047,7 @@ type UnilateralCloseSummary struct {
 // happen in case we have lost state) it should be set to an empty struct, in
 // which case we will attempt to sweep the non-HTLC output using the passed
 // commitPoint.
-func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
+func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer input.Signer,
 	pCache PreimageCache, commitSpend *chainntnfs.SpendDetail,
 	remoteCommit channeldb.ChannelCommitment,
 	commitPoint *btcec.PublicKey) (*UnilateralCloseSummary, error) {
@@ -5074,7 +5075,7 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 	// Before we can generate the proper sign descriptor, we'll need to
 	// locate the output index of our non-delayed output on the commitment
 	// transaction.
-	selfP2WKH, err := CommitScriptUnencumbered(keyRing.NoDelayKey)
+	selfP2WKH, err := input.CommitScriptUnencumbered(keyRing.NoDelayKey)
 	if err != nil {
 		return nil, fmt.Errorf("unable to create self commit script: %v", err)
 	}
@@ -5103,7 +5104,7 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 		localPayBase := chanState.LocalChanCfg.PaymentBasePoint
 		commitResolution = &CommitOutputResolution{
 			SelfOutPoint: *selfPoint,
-			SelfOutputSignDesc: SignDescriptor{
+			SelfOutputSignDesc: input.SignDescriptor{
 				KeyDesc:       localPayBase,
 				SingleTweak:   keyRing.LocalCommitKeyTweak,
 				WitnessScript: selfP2WKH,
@@ -5190,7 +5191,7 @@ type IncomingHtlcResolution struct {
 	// SweepSignDesc is a sign descriptor that has been populated with the
 	// necessary items required to spend the sole output of the above
 	// transaction.
-	SweepSignDesc SignDescriptor
+	SweepSignDesc input.SignDescriptor
 }
 
 // OutgoingHtlcResolution houses the information necessary to sweep any
@@ -5230,7 +5231,7 @@ type OutgoingHtlcResolution struct {
 	// SweepSignDesc is a sign descriptor that has been populated with the
 	// necessary items required to spend the sole output of the above
 	// transaction.
-	SweepSignDesc SignDescriptor
+	SweepSignDesc input.SignDescriptor
 }
 
 // HtlcResolutions contains the items necessary to sweep HTLC's on chain
@@ -5250,7 +5251,7 @@ type HtlcResolutions struct {
 // newOutgoingHtlcResolution generates a new HTLC resolution capable of
 // allowing the caller to sweep an outgoing HTLC present on either their, or
 // the remote party's commitment transaction.
-func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelConfig,
+func newOutgoingHtlcResolution(signer input.Signer, localChanCfg *channeldb.ChannelConfig,
 	commitHash chainhash.Hash, htlc *channeldb.HTLC, keyRing *CommitmentKeyRing,
 	feePerKw SatPerKWeight, dustLimit btcutil.Amount, csvDelay uint32, localCommit bool,
 ) (*OutgoingHtlcResolution, error) {
@@ -5266,14 +5267,14 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	if !localCommit {
 		// First, we'll re-generate the script used to send the HTLC to
 		// the remote party within their commitment transaction.
-		htlcReceiverScript, err := receiverHTLCScript(htlc.RefundTimeout,
+		htlcReceiverScript, err := input.ReceiverHTLCScript(htlc.RefundTimeout,
 			keyRing.LocalHtlcKey, keyRing.RemoteHtlcKey,
 			keyRing.RevocationKey, htlc.RHash[:],
 		)
 		if err != nil {
 			return nil, err
 		}
-		htlcScriptHash, err := WitnessScriptHash(htlcReceiverScript)
+		htlcScriptHash, err := input.WitnessScriptHash(htlcReceiverScript)
 		if err != nil {
 			return nil, err
 		}
@@ -5283,7 +5284,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 		return &OutgoingHtlcResolution{
 			Expiry:        htlc.RefundTimeout,
 			ClaimOutpoint: op,
-			SweepSignDesc: SignDescriptor{
+			SweepSignDesc: input.SignDescriptor{
 				KeyDesc:       localChanCfg.HtlcBasePoint,
 				SingleTweak:   keyRing.LocalHtlcKeyTweak,
 				WitnessScript: htlcReceiverScript,
@@ -5318,12 +5319,12 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	// With the transaction created, we can generate a sign descriptor
 	// that's capable of generating the signature required to spend the
 	// HTLC output using the timeout transaction.
-	htlcCreationScript, err := senderHTLCScript(keyRing.LocalHtlcKey,
+	htlcCreationScript, err := input.SenderHTLCScript(keyRing.LocalHtlcKey,
 		keyRing.RemoteHtlcKey, keyRing.RevocationKey, htlc.RHash[:])
 	if err != nil {
 		return nil, err
 	}
-	timeoutSignDesc := SignDescriptor{
+	timeoutSignDesc := input.SignDescriptor{
 		KeyDesc:       localChanCfg.HtlcBasePoint,
 		SingleTweak:   keyRing.LocalHtlcKeyTweak,
 		WitnessScript: htlcCreationScript,
@@ -5337,7 +5338,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 
 	// With the sign desc created, we can now construct the full witness
 	// for the timeout transaction, and populate it as well.
-	timeoutWitness, err := senderHtlcSpendTimeout(
+	timeoutWitness, err := input.SenderHtlcSpendTimeout(
 		htlc.Signature, signer, &timeoutSignDesc, timeoutTx,
 	)
 	if err != nil {
@@ -5348,18 +5349,18 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	// Finally, we'll generate the script output that the timeout
 	// transaction creates so we can generate the signDesc required to
 	// complete the claim process after a delay period.
-	htlcSweepScript, err := secondLevelHtlcScript(
+	htlcSweepScript, err := input.SecondLevelHtlcScript(
 		keyRing.RevocationKey, keyRing.DelayKey, csvDelay,
 	)
 	if err != nil {
 		return nil, err
 	}
-	htlcScriptHash, err := WitnessScriptHash(htlcSweepScript)
+	htlcScriptHash, err := input.WitnessScriptHash(htlcSweepScript)
 	if err != nil {
 		return nil, err
 	}
 
-	localDelayTweak := SingleTweakBytes(
+	localDelayTweak := input.SingleTweakBytes(
 		keyRing.CommitPoint, localChanCfg.DelayBasePoint.PubKey,
 	)
 	return &OutgoingHtlcResolution{
@@ -5370,7 +5371,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 			Hash:  timeoutTx.TxHash(),
 			Index: 0,
 		},
-		SweepSignDesc: SignDescriptor{
+		SweepSignDesc: input.SignDescriptor{
 			KeyDesc:       localChanCfg.DelayBasePoint,
 			SingleTweak:   localDelayTweak,
 			WitnessScript: htlcSweepScript,
@@ -5390,7 +5391,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 // they can just sweep the output immediately with knowledge of the pre-image.
 //
 // TODO(roasbeef) consolidate code with above func
-func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelConfig,
+func newIncomingHtlcResolution(signer input.Signer, localChanCfg *channeldb.ChannelConfig,
 	commitHash chainhash.Hash, htlc *channeldb.HTLC, keyRing *CommitmentKeyRing,
 	feePerKw SatPerKWeight, dustLimit btcutil.Amount, csvDelay uint32,
 	localCommit bool, preimage [32]byte) (*IncomingHtlcResolution, error) {
@@ -5405,14 +5406,14 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	if !localCommit {
 		// First, we'll re-generate the script the remote party used to
 		// send the HTLC to us in their commitment transaction.
-		htlcSenderScript, err := senderHTLCScript(
+		htlcSenderScript, err := input.SenderHTLCScript(
 			keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 			keyRing.RevocationKey, htlc.RHash[:],
 		)
 		if err != nil {
 			return nil, err
 		}
-		htlcScriptHash, err := WitnessScriptHash(htlcSenderScript)
+		htlcScriptHash, err := input.WitnessScriptHash(htlcSenderScript)
 		if err != nil {
 			return nil, err
 		}
@@ -5423,7 +5424,7 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 			Preimage:      preimage,
 			ClaimOutpoint: op,
 			CsvDelay:      csvDelay,
-			SweepSignDesc: SignDescriptor{
+			SweepSignDesc: input.SignDescriptor{
 				KeyDesc:       localChanCfg.HtlcBasePoint,
 				SingleTweak:   keyRing.LocalHtlcKeyTweak,
 				WitnessScript: htlcSenderScript,
@@ -5452,14 +5453,14 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 
 	// Once we've created the second-level transaction, we'll generate the
 	// SignDesc needed spend the HTLC output using the success transaction.
-	htlcCreationScript, err := receiverHTLCScript(htlc.RefundTimeout,
+	htlcCreationScript, err := input.ReceiverHTLCScript(htlc.RefundTimeout,
 		keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 		keyRing.RevocationKey, htlc.RHash[:],
 	)
 	if err != nil {
 		return nil, err
 	}
-	successSignDesc := SignDescriptor{
+	successSignDesc := input.SignDescriptor{
 		KeyDesc:       localChanCfg.HtlcBasePoint,
 		SingleTweak:   keyRing.LocalHtlcKeyTweak,
 		WitnessScript: htlcCreationScript,
@@ -5473,7 +5474,7 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 
 	// Next, we'll construct the full witness needed to satisfy the input
 	// of the success transaction.
-	successWitness, err := receiverHtlcSpendRedeem(
+	successWitness, err := input.ReceiverHtlcSpendRedeem(
 		htlc.Signature, preimage[:], signer, &successSignDesc, successTx,
 	)
 	if err != nil {
@@ -5484,18 +5485,18 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	// Finally, we'll generate the script that the second-level transaction
 	// creates so we can generate the proper signDesc to sweep it after the
 	// CSV delay has passed.
-	htlcSweepScript, err := secondLevelHtlcScript(
+	htlcSweepScript, err := input.SecondLevelHtlcScript(
 		keyRing.RevocationKey, keyRing.DelayKey, csvDelay,
 	)
 	if err != nil {
 		return nil, err
 	}
-	htlcScriptHash, err := WitnessScriptHash(htlcSweepScript)
+	htlcScriptHash, err := input.WitnessScriptHash(htlcSweepScript)
 	if err != nil {
 		return nil, err
 	}
 
-	localDelayTweak := SingleTweakBytes(
+	localDelayTweak := input.SingleTweakBytes(
 		keyRing.CommitPoint, localChanCfg.DelayBasePoint.PubKey,
 	)
 	return &IncomingHtlcResolution{
@@ -5506,7 +5507,7 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 			Hash:  successTx.TxHash(),
 			Index: 0,
 		},
-		SweepSignDesc: SignDescriptor{
+		SweepSignDesc: input.SignDescriptor{
 			KeyDesc:       localChanCfg.DelayBasePoint,
 			SingleTweak:   localDelayTweak,
 			WitnessScript: htlcSweepScript,
@@ -5547,7 +5548,7 @@ func (r *OutgoingHtlcResolution) HtlcPoint() wire.OutPoint {
 // the local key used when generating the HTLC scrips. This function is to be
 // used in two cases: force close, or a unilateral close.
 func extractHtlcResolutions(feePerKw SatPerKWeight, ourCommit bool,
-	signer Signer, htlcs []channeldb.HTLC, keyRing *CommitmentKeyRing,
+	signer input.Signer, htlcs []channeldb.HTLC, keyRing *CommitmentKeyRing,
 	localChanCfg, remoteChanCfg *channeldb.ChannelConfig,
 	commitHash chainhash.Hash, pCache PreimageCache) (*HtlcResolutions, error) {
 
@@ -5692,7 +5693,7 @@ func (lc *LightningChannel) ForceClose() (*LocalForceCloseSummary, error) {
 // NewLocalForceCloseSummary generates a LocalForceCloseSummary from the given
 // channel state.  The passed commitTx must be a fully signed commitment
 // transaction corresponding to localCommit.
-func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
+func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer input.Signer,
 	pCache PreimageCache, commitTx *wire.MsgTx,
 	localCommit channeldb.ChannelCommitment) (*LocalForceCloseSummary, error) {
 
@@ -5707,15 +5708,15 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 	if err != nil {
 		return nil, err
 	}
-	commitPoint := ComputeCommitmentPoint(revocation[:])
+	commitPoint := input.ComputeCommitmentPoint(revocation[:])
 	keyRing := deriveCommitmentKeys(commitPoint, true, &chanState.LocalChanCfg,
 		&chanState.RemoteChanCfg)
-	selfScript, err := CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
+	selfScript, err := input.CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
 		keyRing.RevocationKey)
 	if err != nil {
 		return nil, err
 	}
-	payToUsScriptHash, err := WitnessScriptHash(selfScript)
+	payToUsScriptHash, err := input.WitnessScriptHash(selfScript)
 	if err != nil {
 		return nil, err
 	}
@@ -5745,7 +5746,7 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 	// nil.
 	var commitResolution *CommitOutputResolution
 	if len(delayScript) != 0 {
-		singleTweak := SingleTweakBytes(
+		singleTweak := input.SingleTweakBytes(
 			commitPoint, chanState.LocalChanCfg.DelayBasePoint.PubKey,
 		)
 		localBalance := localCommit.LocalBalance
@@ -5754,7 +5755,7 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 				Hash:  commitTx.TxHash(),
 				Index: delayIndex,
 			},
-			SelfOutputSignDesc: SignDescriptor{
+			SelfOutputSignDesc: input.SignDescriptor{
 				KeyDesc:       chanState.LocalChanCfg.DelayBasePoint,
 				SingleTweak:   singleTweak,
 				WitnessScript: selfScript,
@@ -5916,7 +5917,7 @@ func (lc *LightningChannel) CompleteCooperativeClose(localSig, remoteSig []byte,
 	// pubkeys+sigs on the stack.
 	ourKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	theirKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
-	witness := SpendMultiSig(lc.signDesc.WitnessScript, ourKey,
+	witness := input.SpendMultiSig(lc.signDesc.WitnessScript, ourKey,
 		localSig, theirKey, remoteSig)
 	closeTx.TxIn[0].Witness = witness
 
@@ -6121,7 +6122,7 @@ func (lc *LightningChannel) generateRevocation(height uint64) (*lnwire.RevokeAnd
 		return nil, err
 	}
 
-	revocationMsg.NextRevocationKey = ComputeCommitmentPoint(nextCommitSecret[:])
+	revocationMsg.NextRevocationKey = input.ComputeCommitmentPoint(nextCommitSecret[:])
 	revocationMsg.ChanID = lnwire.NewChanIDFromOutPoint(
 		&lc.channelState.FundingOutpoint)
 
@@ -6142,19 +6143,19 @@ func CreateCommitTx(fundingOutput wire.TxIn,
 	// output after a relative block delay, or the remote node can claim
 	// the funds with the revocation key if we broadcast a revoked
 	// commitment transaction.
-	ourRedeemScript, err := CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
+	ourRedeemScript, err := input.CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
 		keyRing.RevocationKey)
 	if err != nil {
 		return nil, err
 	}
-	payToUsScriptHash, err := WitnessScriptHash(ourRedeemScript)
+	payToUsScriptHash, err := input.WitnessScriptHash(ourRedeemScript)
 	if err != nil {
 		return nil, err
 	}
 
 	// Next, we create the script paying to them. This is just a regular
 	// P2WPKH output, without any added CSV delay.
-	theirWitnessKeyHash, err := CommitScriptUnencumbered(keyRing.NoDelayKey)
+	theirWitnessKeyHash, err := input.CommitScriptUnencumbered(keyRing.NoDelayKey)
 	if err != nil {
 		return nil, err
 	}
@@ -6223,7 +6224,7 @@ func CreateCooperativeCloseTx(fundingTxIn wire.TxIn,
 // CalcFee returns the commitment fee to use for the given
 // fee rate (fee-per-kw).
 func (lc *LightningChannel) CalcFee(feeRate SatPerKWeight) btcutil.Amount {
-	return feeRate.FeeForWeight(CommitWeight)
+	return feeRate.FeeForWeight(input.CommitWeight)
 }
 
 // RemoteNextRevocation returns the channelState's RemoteNextRevocation.

lnwallet/channel_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -403,7 +404,7 @@ func TestCheckCommitTxSize(t *testing.T) {
 		}
 
 		actualCost := blockchain.GetTransactionWeight(btcutil.NewTx(commitTx))
-		estimatedCost := estimateCommitTxWeight(count, false)
+		estimatedCost := input.EstimateCommitTxWeight(count, false)
 
 		diff := int(estimatedCost - actualCost)
 		if 0 > diff || BaseCommitmentTxSizeEstimationError < diff {
@@ -624,7 +625,7 @@ func TestForceClose(t *testing.T) {
 
 	// Factoring in the fee rate, Alice's amount should properly reflect
 	// that we've added two additional HTLC to the commitment transaction.
-	totalCommitWeight := CommitWeight + (HtlcWeight * 2)
+	totalCommitWeight := input.CommitWeight + (input.HtlcWeight * 2)
 	feePerKw := SatPerKWeight(aliceChannel.channelState.LocalCommitment.FeePerKw)
 	commitFee := feePerKw.FeeForWeight(totalCommitWeight)
 	expectedAmount := (aliceChannel.Capacity / 2) - htlcAmount.ToSatoshis() - commitFee
@@ -680,7 +681,7 @@ func TestForceClose(t *testing.T) {
 		Value:    htlcResolution.SweepSignDesc.Output.Value,
 	})
 	htlcResolution.SweepSignDesc.InputIndex = 0
-	sweepTx.TxIn[0].Witness, err = htlcSpendSuccess(aliceChannel.Signer,
+	sweepTx.TxIn[0].Witness, err = input.HtlcSpendSuccess(aliceChannel.Signer,
 		&htlcResolution.SweepSignDesc, sweepTx,
 		uint32(aliceChannel.channelState.LocalChanCfg.CsvDelay))
 	if err != nil {
@@ -741,7 +742,7 @@ func TestForceClose(t *testing.T) {
 		Value:    inHtlcResolution.SweepSignDesc.Output.Value,
 	})
 	inHtlcResolution.SweepSignDesc.InputIndex = 0
-	sweepTx.TxIn[0].Witness, err = htlcSpendSuccess(aliceChannel.Signer,
+	sweepTx.TxIn[0].Witness, err = input.HtlcSpendSuccess(aliceChannel.Signer,
 		&inHtlcResolution.SweepSignDesc, sweepTx,
 		uint32(aliceChannel.channelState.LocalChanCfg.CsvDelay))
 	if err != nil {
@@ -5007,7 +5008,7 @@ func TestChannelUnilateralCloseHtlcResolution(t *testing.T) {
 
 	// With the transaction constructed, we'll generate a witness that
 	// should be valid for it, and verify using an instance of Script.
-	sweepTx.TxIn[0].Witness, err = receiverHtlcSpendTimeout(
+	sweepTx.TxIn[0].Witness, err = input.ReceiverHtlcSpendTimeout(
 		aliceChannel.Signer, &outHtlcResolution.SweepSignDesc,
 		sweepTx, int32(outHtlcResolution.Expiry),
 	)
@@ -5041,7 +5042,7 @@ func TestChannelUnilateralCloseHtlcResolution(t *testing.T) {
 	inHtlcResolution.SweepSignDesc.SigHashes = txscript.NewTxSigHashes(
 		sweepTx,
 	)
-	sweepTx.TxIn[0].Witness, err = SenderHtlcSpendRedeem(
+	sweepTx.TxIn[0].Witness, err = input.SenderHtlcSpendRedeem(
 		aliceChannel.Signer, &inHtlcResolution.SweepSignDesc,
 		sweepTx, preimageBob[:],
 	)
@@ -5172,7 +5173,7 @@ func TestChannelUnilateralClosePendingCommit(t *testing.T) {
 		Value:    aliceSignDesc.Output.Value,
 	})
 	aliceSignDesc.SigHashes = txscript.NewTxSigHashes(sweepTx)
-	sweepTx.TxIn[0].Witness, err = CommitSpendNoDelay(
+	sweepTx.TxIn[0].Witness, err = input.CommitSpendNoDelay(
 		aliceChannel.Signer, &aliceSignDesc, sweepTx,
 	)
 	if err != nil {

lnwallet/config.go

@@ -4,6 +4,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 )
 
@@ -37,7 +38,7 @@ type Config struct {
 	// 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
+	Signer input.Signer
 
 	// FeeEstimator is the implementation that the wallet will use for the
 	// calculation of on-chain transaction fees.

lnwallet/interface.go

@@ -253,30 +253,6 @@ type BlockChainIO interface {
 	GetBlock(blockHash *chainhash.Hash) (*wire.MsgBlock, error)
 }
 
-// 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 regular p2sh output.
-	//
-	// NOTE: This method will ignore any tweak parameters set within the
-	// passed SignDescriptor as it assumes a set of typical script
-	// templates (p2wkh, np2wkh, etc).
-	ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*InputScript, error)
-}
-
 // MessageSigner represents an abstract object capable of signing arbitrary
 // messages. The capabilities of this interface are used to sign announcements
 // to the network, or just arbitrary messages that leverage the wallet's keys

lnwallet/interface_test.go

@@ -35,6 +35,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
@@ -353,7 +354,7 @@ func loadTestCredits(miner *rpctest.Harness, w *lnwallet.LightningWallet,
 func createTestWallet(tempTestDir string, miningNode *rpctest.Harness,
 	netParams *chaincfg.Params, notifier chainntnfs.ChainNotifier,
 	wc lnwallet.WalletController, keyRing keychain.SecretKeyRing,
-	signer lnwallet.Signer, bio lnwallet.BlockChainIO) (*lnwallet.LightningWallet, error) {
+	signer input.Signer, bio lnwallet.BlockChainIO) (*lnwallet.LightningWallet, error) {
 
 	dbDir := filepath.Join(tempTestDir, "cdb")
 	cdb, err := channeldb.Open(dbDir)
@@ -434,7 +435,7 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness,
 		ChanReserve:      fundingAmount / 100,
 		MaxPendingAmount: lnwire.NewMSatFromSatoshis(fundingAmount),
 		MinHTLC:          1,
-		MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+		MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 		CsvDelay:         csvDelay,
 	}
 	err = aliceChanReservation.CommitConstraints(channelConstraints)
@@ -866,7 +867,7 @@ func testSingleFunderReservationWorkflow(miner *rpctest.Harness,
 		ChanReserve:      fundingAmt / 100,
 		MaxPendingAmount: lnwire.NewMSatFromSatoshis(fundingAmt),
 		MinHTLC:          1,
-		MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+		MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 		CsvDelay:         csvDelay,
 	}
 	err = aliceChanReservation.CommitConstraints(channelConstraints)
@@ -1528,7 +1529,7 @@ func testPublishTransaction(r *rpctest.Harness,
 
 		// Now we can populate the sign descriptor which we'll use to
 		// generate the signature.
-		signDesc := &lnwallet.SignDescriptor{
+		signDesc := &input.SignDescriptor{
 			KeyDesc: keychain.KeyDescriptor{
 				PubKey: pubKey.PubKey,
 			},
@@ -1783,10 +1784,10 @@ func testSignOutputUsingTweaks(r *rpctest.Harness,
 	commitSecret, commitPoint := btcec.PrivKeyFromBytes(btcec.S256(),
 		commitPreimage)
 
-	revocationKey := lnwallet.DeriveRevocationPubkey(pubKey.PubKey, commitPoint)
-	commitTweak := lnwallet.SingleTweakBytes(commitPoint, pubKey.PubKey)
+	revocationKey := input.DeriveRevocationPubkey(pubKey.PubKey, commitPoint)
+	commitTweak := input.SingleTweakBytes(commitPoint, pubKey.PubKey)
 
-	tweakedPub := lnwallet.TweakPubKey(pubKey.PubKey, commitPoint)
+	tweakedPub := input.TweakPubKey(pubKey.PubKey, commitPoint)
 
 	// As we'd like to test both single and double tweaks, we'll repeat
 	// the same set up twice. The first will use a regular single tweak,
@@ -1856,7 +1857,7 @@ func testSignOutputUsingTweaks(r *rpctest.Harness,
 		// private tweak value as the key in the script is derived
 		// based on this tweak value and the key we originally
 		// generated above.
-		signDesc := &lnwallet.SignDescriptor{
+		signDesc := &input.SignDescriptor{
 			KeyDesc: keychain.KeyDescriptor{
 				PubKey: baseKey.PubKey,
 			},
@@ -2392,8 +2393,8 @@ func runTests(t *testing.T, walletDriver *lnwallet.WalletDriver,
 	var (
 		bio lnwallet.BlockChainIO
 
-		aliceSigner lnwallet.Signer
-		bobSigner   lnwallet.Signer
+		aliceSigner input.Signer
+		bobSigner   input.Signer
 
 		aliceKeyRing keychain.SecretKeyRing
 		bobKeyRing   keychain.SecretKeyRing

lnwallet/parameters.go

@@ -3,10 +3,11 @@ package lnwallet
 import (
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcwallet/wallet/txrules"
+	"github.com/lightningnetwork/lnd/input"
 )
 
 // DefaultDustLimit is used to calculate the dust HTLC amount which will be
 // send to other node during funding process.
 func DefaultDustLimit() btcutil.Amount {
-	return txrules.GetDustThreshold(P2WSHSize, txrules.DefaultRelayFeePerKb)
+	return txrules.GetDustThreshold(input.P2WSHSize, txrules.DefaultRelayFeePerKb)
 }

lnwallet/reservation.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -49,18 +50,6 @@ func (c *ChannelContribution) toChanConfig() channeldb.ChannelConfig {
 	return *c.ChannelConfig
 }
 
-// InputScript represents any script inputs required to redeem a previous
-// output. This struct is used rather than just a witness, or scripSig in order
-// to accommodate nested p2sh which utilizes both types of input scripts.
-type InputScript struct {
-	// Witness is the full witness stack required to unlock this output.
-	Witness wire.TxWitness
-
-	// SigScript will only be populated if this is an input script sweeping
-	// a nested p2sh output.
-	SigScript []byte
-}
-
 // ChannelReservation represents an intent to open a lightning payment channel
 // with a counterparty. The funding processes from reservation to channel opening
 // is a 3-step process. In order to allow for full concurrency during the
@@ -102,8 +91,8 @@ type ChannelReservation struct {
 
 	// In order of sorted inputs. Sorting is done in accordance
 	// to BIP-69: https://github.com/bitcoin/bips/blob/master/bip-0069.mediawiki.
-	ourFundingInputScripts   []*InputScript
-	theirFundingInputScripts []*InputScript
+	ourFundingInputScripts   []*input.Script
+	theirFundingInputScripts []*input.Script
 
 	// Our signature for their version of the commitment transaction.
 	ourCommitmentSig   []byte
@@ -149,7 +138,7 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount,
 		initiator    bool
 	)
 
-	commitFee := commitFeePerKw.FeeForWeight(CommitWeight)
+	commitFee := commitFeePerKw.FeeForWeight(input.CommitWeight)
 	fundingMSat := lnwire.NewMSatFromSatoshis(fundingAmt)
 	capacityMSat := lnwire.NewMSatFromSatoshis(capacity)
 	feeMSat := lnwire.NewMSatFromSatoshis(commitFee)
@@ -320,9 +309,9 @@ func (r *ChannelReservation) CommitConstraints(c *channeldb.ChannelConstraints)
 
 	// Fail if maxHtlcs is above the maximum allowed number of 483.  This
 	// number is specified in BOLT-02.
-	if c.MaxAcceptedHtlcs > uint16(MaxHTLCNumber/2) {
+	if c.MaxAcceptedHtlcs > uint16(input.MaxHTLCNumber/2) {
 		return ErrMaxHtlcNumTooLarge(
-			c.MaxAcceptedHtlcs, uint16(MaxHTLCNumber/2),
+			c.MaxAcceptedHtlcs, uint16(input.MaxHTLCNumber/2),
 		)
 	}
 
@@ -424,7 +413,7 @@ func (r *ChannelReservation) TheirContribution() *ChannelContribution {
 //
 // NOTE: These signatures will only be populated after a call to
 // .ProcessContribution()
-func (r *ChannelReservation) OurSignatures() ([]*InputScript, []byte) {
+func (r *ChannelReservation) OurSignatures() ([]*input.Script, []byte) {
 	r.RLock()
 	defer r.RUnlock()
 	return r.ourFundingInputScripts, r.ourCommitmentSig
@@ -443,7 +432,7 @@ func (r *ChannelReservation) OurSignatures() ([]*InputScript, []byte) {
 // block until the funding transaction obtains the configured number of
 // confirmations. Once the method unblocks, a LightningChannel instance is
 // returned, marking the channel available for updates.
-func (r *ChannelReservation) CompleteReservation(fundingInputScripts []*InputScript,
+func (r *ChannelReservation) CompleteReservation(fundingInputScripts []*input.Script,
 	commitmentSig []byte) (*channeldb.OpenChannel, error) {
 
 	// TODO(roasbeef): add flag for watch or not?
@@ -494,7 +483,7 @@ func (r *ChannelReservation) CompleteReservationSingle(fundingPoint *wire.OutPoi
 //
 // NOTE: These attributes will be unpopulated before a call to
 // .CompleteReservation().
-func (r *ChannelReservation) TheirSignatures() ([]*InputScript, []byte) {
+func (r *ChannelReservation) TheirSignatures() ([]*input.Script, []byte) {
 	r.RLock()
 	defer r.RUnlock()
 	return r.theirFundingInputScripts, r.theirCommitmentSig

lnwallet/signdescriptor.go

@@ -1,225 +0,0 @@
-package lnwallet
-
-import (
-	"encoding/binary"
-	"errors"
-	"io"
-
-	"github.com/btcsuite/btcd/btcec"
-	"github.com/btcsuite/btcd/txscript"
-	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/keychain"
-)
-
-var (
-	// ErrTweakOverdose signals a SignDescriptor is invalid because both of its
-	// SingleTweak and DoubleTweak are non-nil.
-	ErrTweakOverdose = errors.New("sign descriptor should only have one tweak")
-)
-
-// SignDescriptor houses the necessary information required to successfully sign
-// a given output. This struct is used by the Signer interface in order to gain
-// access to critical data needed to generate a valid signature.
-type SignDescriptor struct {
-	// KeyDesc is a descriptor that precisely describes *which* key to use
-	// for signing. This may provide the raw public key directly, or
-	// require the Signer to re-derive the key according to the populated
-	// derivation path.
-	KeyDesc keychain.KeyDescriptor
-
-	// SingleTweak is a scalar value that will be added to the private key
-	// corresponding to the above public key to obtain the private key to
-	// be used to sign this input. This value is typically derived via the
-	// following computation:
-	//
-	//  * derivedKey = privkey + sha256(perCommitmentPoint || pubKey) mod N
-	//
-	// NOTE: If this value is nil, then the input can be signed using only
-	// the above public key. Either a SingleTweak should be set or a
-	// DoubleTweak, not both.
-	SingleTweak []byte
-
-	// DoubleTweak is a private key that will be used in combination with
-	// its corresponding private key to derive the private key that is to
-	// be used to sign the target input. Within the Lightning protocol,
-	// this value is typically the commitment secret from a previously
-	// revoked commitment transaction. This value is in combination with
-	// two hash values, and the original private key to derive the private
-	// key to be used when signing.
-	//
-	//  * k = (privKey*sha256(pubKey || tweakPub) +
-	//        tweakPriv*sha256(tweakPub || pubKey)) mod N
-	//
-	// NOTE: If this value is nil, then the input can be signed using only
-	// the above public key. Either a SingleTweak should be set or a
-	// DoubleTweak, not both.
-	DoubleTweak *btcec.PrivateKey
-
-	// WitnessScript 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.
-	WitnessScript []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
-}
-
-// WriteSignDescriptor serializes a SignDescriptor struct into the passed
-// io.Writer stream.
-//
-// NOTE: We assume the SigHashes and InputIndex fields haven't been assigned
-// yet, since that is usually done just before broadcast by the witness
-// generator.
-func WriteSignDescriptor(w io.Writer, sd *SignDescriptor) error {
-	err := binary.Write(w, binary.BigEndian, sd.KeyDesc.Family)
-	if err != nil {
-		return err
-	}
-	err = binary.Write(w, binary.BigEndian, sd.KeyDesc.Index)
-	if err != nil {
-		return err
-	}
-
-	err = binary.Write(w, binary.BigEndian, sd.KeyDesc.PubKey != nil)
-	if err != nil {
-		return err
-	}
-
-	if sd.KeyDesc.PubKey != nil {
-		serializedPubKey := sd.KeyDesc.PubKey.SerializeCompressed()
-		if err := wire.WriteVarBytes(w, 0, serializedPubKey); err != nil {
-			return err
-		}
-	}
-
-	if err := wire.WriteVarBytes(w, 0, sd.SingleTweak); err != nil {
-		return err
-	}
-
-	var doubleTweakBytes []byte
-	if sd.DoubleTweak != nil {
-		doubleTweakBytes = sd.DoubleTweak.Serialize()
-	}
-	if err := wire.WriteVarBytes(w, 0, doubleTweakBytes); err != nil {
-		return err
-	}
-
-	if err := wire.WriteVarBytes(w, 0, sd.WitnessScript); err != nil {
-		return err
-	}
-
-	if err := writeTxOut(w, sd.Output); err != nil {
-		return err
-	}
-
-	var scratch [4]byte
-	binary.BigEndian.PutUint32(scratch[:], uint32(sd.HashType))
-	if _, err := w.Write(scratch[:]); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-// ReadSignDescriptor deserializes a SignDescriptor struct from the passed
-// io.Reader stream.
-func ReadSignDescriptor(r io.Reader, sd *SignDescriptor) error {
-	err := binary.Read(r, binary.BigEndian, &sd.KeyDesc.Family)
-	if err != nil {
-		return err
-	}
-	err = binary.Read(r, binary.BigEndian, &sd.KeyDesc.Index)
-	if err != nil {
-		return err
-	}
-
-	var hasKey bool
-	err = binary.Read(r, binary.BigEndian, &hasKey)
-	if err != nil {
-		return err
-	}
-
-	if hasKey {
-		pubKeyBytes, err := wire.ReadVarBytes(r, 0, 34, "pubkey")
-		if err != nil {
-			return err
-		}
-		sd.KeyDesc.PubKey, err = btcec.ParsePubKey(
-			pubKeyBytes, btcec.S256(),
-		)
-		if err != nil {
-			return err
-		}
-	}
-
-	singleTweak, err := wire.ReadVarBytes(r, 0, 32, "singleTweak")
-	if err != nil {
-		return err
-	}
-
-	// Serializing a SignDescriptor with a nil-valued SingleTweak results
-	// in deserializing a zero-length slice. Since a nil-valued SingleTweak
-	// has special meaning and a zero-length slice for a SingleTweak is
-	// invalid, we can use the zero-length slice as the flag for a
-	// nil-valued SingleTweak.
-	if len(singleTweak) == 0 {
-		sd.SingleTweak = nil
-	} else {
-		sd.SingleTweak = singleTweak
-	}
-
-	doubleTweakBytes, err := wire.ReadVarBytes(r, 0, 32, "doubleTweak")
-	if err != nil {
-		return err
-	}
-
-	// Serializing a SignDescriptor with a nil-valued DoubleTweak results
-	// in deserializing a zero-length slice. Since a nil-valued DoubleTweak
-	// has special meaning and a zero-length slice for a DoubleTweak is
-	// invalid, we can use the zero-length slice as the flag for a
-	// nil-valued DoubleTweak.
-	if len(doubleTweakBytes) == 0 {
-		sd.DoubleTweak = nil
-	} else {
-		sd.DoubleTweak, _ = btcec.PrivKeyFromBytes(btcec.S256(), doubleTweakBytes)
-	}
-
-	// Only one tweak should ever be set, fail if both are present.
-	if sd.SingleTweak != nil && sd.DoubleTweak != nil {
-		return ErrTweakOverdose
-	}
-
-	witnessScript, err := wire.ReadVarBytes(r, 0, 500, "witnessScript")
-	if err != nil {
-		return err
-	}
-	sd.WitnessScript = witnessScript
-
-	txOut := &wire.TxOut{}
-	if err := readTxOut(r, txOut); err != nil {
-		return err
-	}
-	sd.Output = txOut
-
-	var hashType [4]byte
-	if _, err := io.ReadFull(r, hashType[:]); err != nil {
-		return err
-	}
-	sd.HashType = txscript.SigHashType(binary.BigEndian.Uint32(hashType[:]))
-
-	return nil
-}

lnwallet/signdescriptor_test.go

@@ -1,129 +0,0 @@
-package lnwallet
-
-import (
-	"bytes"
-	"reflect"
-	"testing"
-
-	"github.com/btcsuite/btcd/btcec"
-	"github.com/btcsuite/btcd/txscript"
-	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/keychain"
-)
-
-func TestSignDescriptorSerialization(t *testing.T) {
-	keys := [][]byte{
-		{0x04, 0x11, 0xdb, 0x93, 0xe1, 0xdc, 0xdb, 0x8a,
-			0x01, 0x6b, 0x49, 0x84, 0x0f, 0x8c, 0x53, 0xbc, 0x1e,
-			0xb6, 0x8a, 0x38, 0x2e, 0x97, 0xb1, 0x48, 0x2e, 0xca,
-			0xd7, 0xb1, 0x48, 0xa6, 0x90, 0x9a, 0x5c, 0xb2, 0xe0,
-			0xea, 0xdd, 0xfb, 0x84, 0xcc, 0xf9, 0x74, 0x44, 0x64,
-			0xf8, 0x2e, 0x16, 0x0b, 0xfa, 0x9b, 0x8b, 0x64, 0xf9,
-			0xd4, 0xc0, 0x3f, 0x99, 0x9b, 0x86, 0x43, 0xf6, 0x56,
-			0xb4, 0x12, 0xa3,
-		},
-		{0x04, 0x11, 0xdb, 0x93, 0xe1, 0xdc, 0xdb, 0x8a,
-			0x01, 0x6b, 0x49, 0x84, 0x0f, 0x8c, 0x53, 0xbc, 0x1e,
-			0xb6, 0x8a, 0x38, 0x2e, 0x97, 0xb1, 0x48, 0x2e, 0xca,
-			0xd7, 0xb1, 0x48, 0xa6, 0x90, 0x9a, 0x5c, 0xb2, 0xe0,
-			0xea, 0xdd, 0xfb, 0x84, 0xcc, 0xf9, 0x74, 0x44, 0x64,
-			0xf8, 0x2e, 0x16, 0x0b, 0xfa, 0x9b, 0x8b, 0x64, 0xf9,
-			0xd4, 0xc0, 0x3f, 0x99, 0x9b, 0x86, 0x43, 0xf6, 0x56,
-			0xb4, 0x12, 0xa3,
-		},
-	}
-
-	signDescriptors := []SignDescriptor{
-		{
-			SingleTweak: []byte{
-				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
-				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
-				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
-				0x02, 0x02, 0x02, 0x02, 0x02,
-			},
-			WitnessScript: []byte{
-				0x00, 0x14, 0xee, 0x91, 0x41, 0x7e, 0x85, 0x6c, 0xde,
-				0x10, 0xa2, 0x91, 0x1e, 0xdc, 0xbd, 0xbd, 0x69, 0xe2,
-				0xef, 0xb5, 0x71, 0x48,
-			},
-			Output: &wire.TxOut{
-				Value: 5000000000,
-				PkScript: []byte{
-					0x41, // OP_DATA_65
-					0x04, 0xd6, 0x4b, 0xdf, 0xd0, 0x9e, 0xb1, 0xc5,
-					0xfe, 0x29, 0x5a, 0xbd, 0xeb, 0x1d, 0xca, 0x42,
-					0x81, 0xbe, 0x98, 0x8e, 0x2d, 0xa0, 0xb6, 0xc1,
-					0xc6, 0xa5, 0x9d, 0xc2, 0x26, 0xc2, 0x86, 0x24,
-					0xe1, 0x81, 0x75, 0xe8, 0x51, 0xc9, 0x6b, 0x97,
-					0x3d, 0x81, 0xb0, 0x1c, 0xc3, 0x1f, 0x04, 0x78,
-					0x34, 0xbc, 0x06, 0xd6, 0xd6, 0xed, 0xf6, 0x20,
-					0xd1, 0x84, 0x24, 0x1a, 0x6a, 0xed, 0x8b, 0x63,
-					0xa6, // 65-byte signature
-					0xac, // OP_CHECKSIG
-				},
-			},
-			HashType: txscript.SigHashAll,
-		},
-
-		// Test serializing a SignDescriptor with a nil-valued PrivateTweak
-		{
-			SingleTweak: nil,
-			WitnessScript: []byte{
-				0x00, 0x14, 0xee, 0x91, 0x41, 0x7e, 0x85, 0x6c, 0xde,
-				0x10, 0xa2, 0x91, 0x1e, 0xdc, 0xbd, 0xbd, 0x69, 0xe2,
-				0xef, 0xb5, 0x71, 0x48,
-			},
-			Output: &wire.TxOut{
-				Value: 5000000000,
-				PkScript: []byte{
-					0x41, // OP_DATA_65
-					0x04, 0xd6, 0x4b, 0xdf, 0xd0, 0x9e, 0xb1, 0xc5,
-					0xfe, 0x29, 0x5a, 0xbd, 0xeb, 0x1d, 0xca, 0x42,
-					0x81, 0xbe, 0x98, 0x8e, 0x2d, 0xa0, 0xb6, 0xc1,
-					0xc6, 0xa5, 0x9d, 0xc2, 0x26, 0xc2, 0x86, 0x24,
-					0xe1, 0x81, 0x75, 0xe8, 0x51, 0xc9, 0x6b, 0x97,
-					0x3d, 0x81, 0xb0, 0x1c, 0xc3, 0x1f, 0x04, 0x78,
-					0x34, 0xbc, 0x06, 0xd6, 0xd6, 0xed, 0xf6, 0x20,
-					0xd1, 0x84, 0x24, 0x1a, 0x6a, 0xed, 0x8b, 0x63,
-					0xa6, // 65-byte signature
-					0xac, // OP_CHECKSIG
-				},
-			},
-			HashType: txscript.SigHashAll,
-		},
-	}
-
-	for i := 0; i < len(signDescriptors); i++ {
-		// Parse pubkeys for each sign descriptor.
-		sd := &signDescriptors[i]
-		pubkey, err := btcec.ParsePubKey(keys[i], btcec.S256())
-		if err != nil {
-			t.Fatalf("unable to parse pubkey: %v", err)
-		}
-		sd.KeyDesc = keychain.KeyDescriptor{
-			KeyLocator: keychain.KeyLocator{
-				Family: 50,
-				Index:  99,
-			},
-			PubKey: pubkey,
-		}
-
-		// Test that serialize -> deserialize yields same result as original.
-		var buf bytes.Buffer
-		if err := WriteSignDescriptor(&buf, sd); err != nil {
-			t.Fatalf("unable to serialize sign descriptor[%v]: %v", i, sd)
-		}
-
-		desSd := &SignDescriptor{}
-		if err := ReadSignDescriptor(&buf, desSd); err != nil {
-			t.Fatalf("unable to deserialize sign descriptor[%v]: %v", i, sd)
-		}
-
-		if !reflect.DeepEqual(sd, desSd) {
-			t.Fatalf("original and deserialized sign descriptors not equal:\n"+
-				"original     : %+v\n"+
-				"deserialized : %+v\n",
-				sd, desSd)
-		}
-	}
-}

lnwallet/sigpool.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -76,7 +77,7 @@ type SignJob struct {
 	// SignDesc is intended to be a full populated SignDescriptor which
 	// encodes the necessary material (keys, witness script, etc) required
 	// to generate a valid signature for the specified input.
-	SignDesc SignDescriptor
+	SignDesc input.SignDescriptor
 
 	// Tx is the transaction to be signed. This is required to generate the
 	// proper sighash for the input to be signed.
@@ -127,7 +128,7 @@ type SigPool struct {
 	started uint32 // To be used atomically.
 	stopped uint32 // To be used atomically.
 
-	signer Signer
+	signer input.Signer
 
 	verifyJobs chan VerifyJob
 	signJobs   chan SignJob
@@ -141,7 +142,7 @@ type SigPool struct {
 // NewSigPool creates a new signature pool with the specified number of
 // workers. The recommended parameter for the number of works is the number of
 // physical CPU cores available on the target machine.
-func NewSigPool(numWorkers int, signer Signer) *SigPool {
+func NewSigPool(numWorkers int, signer input.Signer) *SigPool {
 	return &SigPool{
 		signer:     signer,
 		numWorkers: numWorkers,

lnwallet/size.go

@@ -1,497 +0,0 @@
-package lnwallet
-
-import (
-	"github.com/btcsuite/btcd/blockchain"
-	"github.com/btcsuite/btcd/wire"
-)
-
-const (
-	// CommitWeight is the weight of the base commitment transaction which
-	// includes: one p2wsh input, out p2wkh output, and one p2wsh output.
-	CommitWeight int64 = 724
-
-	// HtlcWeight is the weight of an HTLC output.
-	HtlcWeight int64 = 172
-)
-
-const (
-	// witnessScaleFactor determines the level of "discount" witness data
-	// receives compared to "base" data. A scale factor of 4, denotes that
-	// witness data is 1/4 as cheap as regular non-witness data. Value copied
-	// here for convenience.
-	witnessScaleFactor = blockchain.WitnessScaleFactor
-
-	// The weight(weight), which is different from the !size! (see BIP-141),
-	// is calculated as:
-	// Weight = 4 * BaseSize + WitnessSize (weight).
-	// BaseSize - size of the transaction without witness data (bytes).
-	// WitnessSize - witness size (bytes).
-	// Weight - the metric for determining the weight of the transaction.
-
-	// P2WPKHSize 22 bytes
-	//	- OP_0: 1 byte
-	//	- OP_DATA: 1 byte (PublicKeyHASH160 length)
-	//	- PublicKeyHASH160: 20 bytes
-	P2WPKHSize = 1 + 1 + 20
-
-	// P2WSHSize 34 bytes
-	//	- OP_0: 1 byte
-	//	- OP_DATA: 1 byte (WitnessScriptSHA256 length)
-	//	- WitnessScriptSHA256: 32 bytes
-	P2WSHSize = 1 + 1 + 32
-
-	// P2PKHOutputSize 34 bytes
-	//      - value: 8 bytes
-	//      - var_int: 1 byte (pkscript_length)
-	//      - pkscript (p2pkh): 25 bytes
-	P2PKHOutputSize = 8 + 1 + 25
-
-	// P2WKHOutputSize 31 bytes
-	//      - value: 8 bytes
-	//      - var_int: 1 byte (pkscript_length)
-	//      - pkscript (p2wpkh): 22 bytes
-	P2WKHOutputSize = 8 + 1 + P2WPKHSize
-
-	// P2WSHOutputSize 43 bytes
-	//      - value: 8 bytes
-	//      - var_int: 1 byte (pkscript_length)
-	//      - pkscript (p2wsh): 34 bytes
-	P2WSHOutputSize = 8 + 1 + P2WSHSize
-
-	// P2SHOutputSize 32 bytes
-	//      - value: 8 bytes
-	//      - var_int: 1 byte (pkscript_length)
-	//      - pkscript (p2sh): 23 bytes
-	P2SHOutputSize = 8 + 1 + 23
-
-	// P2PKHScriptSigSize 108 bytes
-	//      - OP_DATA: 1 byte (signature length)
-	//      - signature
-	//      - OP_DATA: 1 byte (pubkey length)
-	//      - pubkey
-	P2PKHScriptSigSize = 1 + 73 + 1 + 33
-
-	// P2WKHWitnessSize 109 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - signature_length: 1 byte
-	//      - signature
-	//      - pubkey_length: 1 byte
-	//      - pubkey
-	P2WKHWitnessSize = 1 + 1 + 73 + 1 + 33
-
-	// MultiSigSize 71 bytes
-	//	- OP_2: 1 byte
-	//	- OP_DATA: 1 byte (pubKeyAlice length)
-	//	- pubKeyAlice: 33 bytes
-	//	- OP_DATA: 1 byte (pubKeyBob length)
-	//	- pubKeyBob: 33 bytes
-	//	- OP_2: 1 byte
-	//	- OP_CHECKMULTISIG: 1 byte
-	MultiSigSize = 1 + 1 + 33 + 1 + 33 + 1 + 1
-
-	// WitnessSize 222 bytes
-	//	- NumberOfWitnessElements: 1 byte
-	//	- NilLength: 1 byte
-	//	- sigAliceLength: 1 byte
-	//	- sigAlice: 73 bytes
-	//	- sigBobLength: 1 byte
-	//	- sigBob: 73 bytes
-	//	- WitnessScriptLength: 1 byte
-	//	- WitnessScript (MultiSig)
-	WitnessSize = 1 + 1 + 1 + 73 + 1 + 73 + 1 + MultiSigSize
-
-	// InputSize 41 bytes
-	//	- PreviousOutPoint:
-	//		- Hash: 32 bytes
-	//		- Index: 4 bytes
-	//	- OP_DATA: 1 byte (ScriptSigLength)
-	//	- ScriptSig: 0 bytes
-	//	- Witness <----	we use "Witness" instead of "ScriptSig" for
-	// 			transaction validation, but "Witness" is stored
-	// 			separately and weight for it size is smaller. So
-	// 			we separate the calculation of ordinary data
-	// 			from witness data.
-	//	- Sequence: 4 bytes
-	InputSize = 32 + 4 + 1 + 4
-
-	// FundingInputSize represents the size of an input to a funding
-	// transaction, and is equivalent to the size of a standard segwit input
-	// as calculated above.
-	FundingInputSize = InputSize
-
-	// CommitmentDelayOutput 43 bytes
-	//	- Value: 8 bytes
-	//	- VarInt: 1 byte (PkScript length)
-	//	- PkScript (P2WSH)
-	CommitmentDelayOutput = 8 + 1 + P2WSHSize
-
-	// CommitmentKeyHashOutput 31 bytes
-	//	- Value: 8 bytes
-	//	- VarInt: 1 byte (PkScript length)
-	//	- PkScript (P2WPKH)
-	CommitmentKeyHashOutput = 8 + 1 + P2WPKHSize
-
-	// HTLCSize 43 bytes
-	//	- Value: 8 bytes
-	//	- VarInt: 1 byte (PkScript length)
-	//	- PkScript (PW2SH)
-	HTLCSize = 8 + 1 + P2WSHSize
-
-	// WitnessHeaderSize 2 bytes
-	//	- Flag: 1 byte
-	//	- Marker: 1 byte
-	WitnessHeaderSize = 1 + 1
-
-	// BaseTxSize 8 bytes
-	//      - Version: 4 bytes
-	//      - LockTime: 4 bytes
-	BaseTxSize = 4 + 4
-
-	// BaseCommitmentTxSize 125 + 43 * num-htlc-outputs bytes
-	//	- Version: 4 bytes
-	//	- WitnessHeader <---- part of the witness data
-	//	- CountTxIn: 1 byte
-	//	- TxIn: 41 bytes
-	//		FundingInput
-	//	- CountTxOut: 1 byte
-	//	- TxOut: 74 + 43 * num-htlc-outputs bytes
-	//		OutputPayingToThem,
-	//		OutputPayingToUs,
-	//		....HTLCOutputs...
-	//	- LockTime: 4 bytes
-	BaseCommitmentTxSize = 4 + 1 + FundingInputSize + 1 +
-		CommitmentDelayOutput + CommitmentKeyHashOutput + 4
-
-	// BaseCommitmentTxWeight 500 weight
-	BaseCommitmentTxWeight = witnessScaleFactor * BaseCommitmentTxSize
-
-	// WitnessCommitmentTxWeight 224 weight
-	WitnessCommitmentTxWeight = WitnessHeaderSize + WitnessSize
-
-	// HTLCWeight 172 weight
-	HTLCWeight = witnessScaleFactor * HTLCSize
-
-	// HtlcTimeoutWeight is the weight of the HTLC timeout transaction
-	// which will transition an outgoing HTLC to the delay-and-claim state.
-	HtlcTimeoutWeight = 663
-
-	// HtlcSuccessWeight is the weight of the HTLC success transaction
-	// which will transition an incoming HTLC to the delay-and-claim state.
-	HtlcSuccessWeight = 703
-
-	// MaxHTLCNumber is the maximum number HTLCs which can be included in a
-	// commitment transaction. This limit was chosen such that, in the case
-	// of a contract breach, the punishment transaction is able to sweep
-	// all the HTLC's yet still remain below the widely used standard
-	// weight limits.
-	MaxHTLCNumber = 966
-
-	// ToLocalScriptSize 79 bytes
-	//      - OP_IF: 1 byte
-	//          - OP_DATA: 1 byte
-	//          - revoke_key: 33 bytes
-	//      - OP_ELSE: 1 byte
-	//          - OP_DATA: 1 byte
-	//          - csv_delay: 4 bytes
-	//          - OP_CHECKSEQUENCEVERIFY: 1 byte
-	//          - OP_DROP: 1 byte
-	//          - OP_DATA: 1 byte
-	//          - delay_key: 33 bytes
-	//      - OP_ENDIF: 1 byte
-	//      - OP_CHECKSIG: 1 byte
-	ToLocalScriptSize = 1 + 1 + 33 + 1 + 1 + 4 + 1 + 1 + 1 + 33 + 1 + 1
-
-	// ToLocalTimeoutWitnessSize 156 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - local_delay_sig_length: 1 byte
-	//      - local_delay_sig: 73 bytes
-	//      - zero_length: 1 byte
-	//      - witness_script_length: 1 byte
-	//      - witness_script (to_local_script)
-	ToLocalTimeoutWitnessSize = 1 + 1 + 73 + 1 + 1 + ToLocalScriptSize
-
-	// ToLocalPenaltyWitnessSize 156 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - revocation_sig_length: 1 byte
-	//      - revocation_sig: 73 bytes
-	//      - OP_TRUE: 1 byte
-	//      - witness_script_length: 1 byte
-	//      - witness_script (to_local_script)
-	ToLocalPenaltyWitnessSize = 1 + 1 + 73 + 1 + 1 + ToLocalScriptSize
-
-	// AcceptedHtlcScriptSize 139 bytes
-	//      - OP_DUP: 1 byte
-	//      - OP_HASH160: 1 byte
-	//      - OP_DATA: 1 byte (RIPEMD160(SHA256(revocationkey)) length)
-	//      - RIPEMD160(SHA256(revocationkey)): 20 bytes
-	//      - OP_EQUAL: 1 byte
-	//      - OP_IF: 1 byte
-	//              - OP_CHECKSIG: 1 byte
-	//      - OP_ELSE: 1 byte
-	//              - OP_DATA: 1 byte (remotekey length)
-	//              - remotekey: 33 bytes
-	//              - OP_SWAP: 1 byte
-	//              - OP_SIZE: 1 byte
-	//              - 32: 1 byte
-	//              - OP_EQUAL: 1 byte
-	//              - OP_IF: 1 byte
-	//                      - OP_HASH160: 1 byte
-	//                      - OP_DATA: 1 byte (RIPEMD160(payment_hash) length)
-	//                      - RIPEMD160(payment_hash): 20 bytes
-	//                      - OP_EQUALVERIFY: 1 byte
-	//                      - 2: 1 byte
-	//                      - OP_SWAP: 1 byte
-	//                      - OP_DATA: 1 byte (localkey length)
-	//                      - localkey: 33 bytes
-	//                      - 2: 1 byte
-	//                      - OP_CHECKMULTISIG: 1 byte
-	//              - OP_ELSE: 1 byte
-	//                      - OP_DROP: 1 byte
-	//                      - OP_DATA: 1 byte (cltv_expiry length)
-	//                      - cltv_expiry: 4 bytes
-	//                      - OP_CHECKLOCKTIMEVERIFY: 1 byte
-	//                      - OP_DROP: 1 byte
-	//                      - OP_CHECKSIG: 1 byte
-	//              - OP_ENDIF: 1 byte
-	//      - OP_ENDIF: 1 byte
-	AcceptedHtlcScriptSize = 3*1 + 20 + 5*1 + 33 + 7*1 + 20 + 4*1 +
-		33 + 5*1 + 4 + 5*1
-
-	// AcceptedHtlcTimeoutWitnessSize 216
-	//      - number_of_witness_elements: 1 byte
-	//      - sender_sig_length: 1 byte
-	//      - sender_sig: 73 bytes
-	//      - nil_length: 1 byte
-	//      - witness_script_length: 1 byte
-	//      - witness_script: (accepted_htlc_script)
-	AcceptedHtlcTimeoutWitnessSize = 1 + 1 + 73 + 1 + 1 + AcceptedHtlcScriptSize
-
-	// AcceptedHtlcSuccessWitnessSize 322 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - nil_length: 1 byte
-	//      - sig_alice_length: 1 byte
-	//      - sig_alice: 73 bytes
-	//      - sig_bob_length: 1 byte
-	//      - sig_bob: 73 bytes
-	//      - preimage_length: 1 byte
-	//      - preimage: 32 bytes
-	//      - witness_script_length: 1 byte
-	//      - witness_script (accepted_htlc_script)
-	AcceptedHtlcSuccessWitnessSize = 1 + 1 + 73 + 1 + 73 + 1 + 32 + 1 + AcceptedHtlcScriptSize
-
-	// AcceptedHtlcPenaltyWitnessSize 249 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - revocation_sig_length: 1 byte
-	//      - revocation_sig: 73 bytes
-	//      - revocation_key_length: 1 byte
-	//      - revocation_key: 33 bytes
-	//      - witness_script_length: 1 byte
-	//      - witness_script (accepted_htlc_script)
-	AcceptedHtlcPenaltyWitnessSize = 1 + 1 + 73 + 1 + 33 + 1 + AcceptedHtlcScriptSize
-
-	// OfferedHtlcScriptSize 133 bytes
-	//      - OP_DUP: 1 byte
-	//      - OP_HASH160: 1 byte
-	//      - OP_DATA: 1 byte (RIPEMD160(SHA256(revocationkey)) length)
-	//      - RIPEMD160(SHA256(revocationkey)): 20 bytes
-	//      - OP_EQUAL: 1 byte
-	//      - OP_IF: 1 byte
-	//              - OP_CHECKSIG: 1 byte
-	//      - OP_ELSE: 1 byte
-	//              - OP_DATA: 1 byte (remotekey length)
-	//              - remotekey: 33 bytes
-	//              - OP_SWAP: 1 byte
-	//              - OP_SIZE: 1 byte
-	//              - OP_DATA: 1 byte (32 length)
-	//              - 32: 1 byte
-	//              - OP_EQUAL: 1 byte
-	//              - OP_NOTIF: 1 byte
-	//                      - OP_DROP: 1 byte
-	//                      - 2: 1 byte
-	//                      - OP_SWAP: 1 byte
-	//                      - OP_DATA: 1 byte (localkey length)
-	//                      - localkey: 33 bytes
-	//                      - 2: 1 byte
-	//                      - OP_CHECKMULTISIG: 1 byte
-	//              - OP_ELSE: 1 byte
-	//                      - OP_HASH160: 1 byte
-	//                      - OP_DATA: 1 byte (RIPEMD160(payment_hash) length)
-	//                      - RIPEMD160(payment_hash): 20 bytes
-	//                      - OP_EQUALVERIFY: 1 byte
-	//                      - OP_CHECKSIG: 1 byte
-	//              - OP_ENDIF: 1 byte
-	//      - OP_ENDIF: 1 byte
-	OfferedHtlcScriptSize = 3*1 + 20 + 5*1 + 33 + 10*1 + 33 + 5*1 + 20 + 4*1
-
-	// OfferedHtlcTimeoutWitnessSize 285 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - nil_length: 1 byte
-	//      - sig_alice_length: 1 byte
-	//      - sig_alice: 73 bytes
-	//      - sig_bob_length: 1 byte
-	//      - sig_bob: 73 bytes
-	//      - nil_length: 1 byte
-	//      - witness_script_length: 1 byte
-	//      - witness_script (offered_htlc_script)
-	OfferedHtlcTimeoutWitnessSize = 1 + 1 + 1 + 73 + 1 + 73 + 1 + 1 + OfferedHtlcScriptSize
-
-	// OfferedHtlcSuccessWitnessSize 317 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - nil_length: 1 byte
-	//      - receiver_sig_length: 1 byte
-	//      - receiver_sig: 73 bytes
-	//      - sender_sig_length: 1 byte
-	//      - sender_sig: 73 bytes
-	//      - payment_preimage_length: 1 byte
-	//      - payment_preimage: 32 bytes
-	//      - witness_script_length: 1 byte
-	//      - witness_script (offered_htlc_script)
-	OfferedHtlcSuccessWitnessSize = 1 + 1 + 1 + 73 + 1 + 73 + 1 + 32 + 1 + OfferedHtlcScriptSize
-
-	// OfferedHtlcPenaltyWitnessSize 243 bytes
-	//      - number_of_witness_elements: 1 byte
-	//      - revocation_sig_length: 1 byte
-	//      - revocation_sig: 73 bytes
-	//      - revocation_key_length: 1 byte
-	//      - revocation_key: 33 bytes
-	//      - witness_script_length: 1 byte
-	//      - witness_script (offered_htlc_script)
-	OfferedHtlcPenaltyWitnessSize = 1 + 1 + 73 + 1 + 33 + 1 + OfferedHtlcScriptSize
-)
-
-// estimateCommitTxWeight estimate commitment transaction weight depending on
-// the precalculated weight of base transaction, witness data, which is needed
-// for paying for funding tx, and htlc weight multiplied by their count.
-func estimateCommitTxWeight(count int, prediction bool) int64 {
-	// Make prediction about the size of commitment transaction with
-	// additional HTLC.
-	if prediction {
-		count++
-	}
-
-	htlcWeight := int64(count * HTLCWeight)
-	baseWeight := int64(BaseCommitmentTxWeight)
-	witnessWeight := int64(WitnessCommitmentTxWeight)
-
-	return htlcWeight + baseWeight + witnessWeight
-}
-
-// TxWeightEstimator is able to calculate weight estimates for transactions
-// based on the input and output types. For purposes of estimation, all
-// signatures are assumed to be of the maximum possible size, 73 bytes. Each
-// method of the estimator returns an instance with the estimate applied. This
-// allows callers to chain each of the methods
-type TxWeightEstimator struct {
-	hasWitness       bool
-	inputCount       uint32
-	outputCount      uint32
-	inputSize        int
-	inputWitnessSize int
-	outputSize       int
-}
-
-// AddP2PKHInput updates the weight estimate to account for an additional input
-// spending a P2PKH output.
-func (twe *TxWeightEstimator) AddP2PKHInput() *TxWeightEstimator {
-	twe.inputSize += InputSize + P2PKHScriptSigSize
-	twe.inputWitnessSize++
-	twe.inputCount++
-
-	return twe
-}
-
-// AddP2WKHInput updates the weight estimate to account for an additional input
-// spending a native P2PWKH output.
-func (twe *TxWeightEstimator) AddP2WKHInput() *TxWeightEstimator {
-	twe.AddWitnessInput(P2WKHWitnessSize)
-
-	return twe
-}
-
-// AddWitnessInput updates the weight estimate to account for an additional
-// input spending a native pay-to-witness output. This accepts the total size
-// of the witness as a parameter.
-func (twe *TxWeightEstimator) AddWitnessInput(witnessSize int) *TxWeightEstimator {
-	twe.inputSize += InputSize
-	twe.inputWitnessSize += witnessSize
-	twe.inputCount++
-	twe.hasWitness = true
-
-	return twe
-}
-
-// AddNestedP2WKHInput updates the weight estimate to account for an additional
-// input spending a P2SH output with a nested P2WKH redeem script.
-func (twe *TxWeightEstimator) AddNestedP2WKHInput() *TxWeightEstimator {
-	twe.inputSize += InputSize + P2WPKHSize
-	twe.inputWitnessSize += P2WKHWitnessSize
-	twe.inputSize++
-	twe.hasWitness = true
-
-	return twe
-}
-
-// AddNestedP2WSHInput updates the weight estimate to account for an additional
-// input spending a P2SH output with a nested P2WSH redeem script.
-func (twe *TxWeightEstimator) AddNestedP2WSHInput(witnessSize int) *TxWeightEstimator {
-	twe.inputSize += InputSize + P2WSHSize
-	twe.inputWitnessSize += witnessSize
-	twe.inputSize++
-	twe.hasWitness = true
-
-	return twe
-}
-
-// AddP2PKHOutput updates the weight estimate to account for an additional P2PKH
-// output.
-func (twe *TxWeightEstimator) AddP2PKHOutput() *TxWeightEstimator {
-	twe.outputSize += P2PKHOutputSize
-	twe.outputCount++
-
-	return twe
-}
-
-// AddP2WKHOutput updates the weight estimate to account for an additional
-// native P2WKH output.
-func (twe *TxWeightEstimator) AddP2WKHOutput() *TxWeightEstimator {
-	twe.outputSize += P2WKHOutputSize
-	twe.outputCount++
-
-	return twe
-}
-
-// AddP2WSHOutput updates the weight estimate to account for an additional
-// native P2WSH output.
-func (twe *TxWeightEstimator) AddP2WSHOutput() *TxWeightEstimator {
-	twe.outputSize += P2WSHOutputSize
-	twe.outputCount++
-
-	return twe
-}
-
-// AddP2SHOutput updates the weight estimate to account for an additional P2SH
-// output.
-func (twe *TxWeightEstimator) AddP2SHOutput() *TxWeightEstimator {
-	twe.outputSize += P2SHOutputSize
-	twe.outputCount++
-
-	return twe
-}
-
-// Weight gets the estimated weight of the transaction.
-func (twe *TxWeightEstimator) Weight() int {
-	txSizeStripped := BaseTxSize +
-		wire.VarIntSerializeSize(uint64(twe.inputCount)) + twe.inputSize +
-		wire.VarIntSerializeSize(uint64(twe.outputCount)) + twe.outputSize
-	weight := txSizeStripped * witnessScaleFactor
-	if twe.hasWitness {
-		weight += WitnessHeaderSize + twe.inputWitnessSize
-	}
-	return weight
-}
-
-// VSize gets the estimated virtual size of the transactions, in vbytes.
-func (twe *TxWeightEstimator) VSize() int {
-	// A tx's vsize is 1/4 of the weight, rounded up.
-	return (twe.Weight() + witnessScaleFactor - 1) / witnessScaleFactor
-}

lnwallet/size_test.go

@@ -8,7 +8,8 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
-	"github.com/lightningnetwork/lnd/lnwallet"
+
+	"github.com/lightningnetwork/lnd/input"
 )
 
 // TestTxWeightEstimator tests that transaction weight estimates are calculated
@@ -106,7 +107,7 @@ func TestTxWeightEstimator(t *testing.T) {
 	}
 
 	for i, test := range testCases {
-		var weightEstimate lnwallet.TxWeightEstimator
+		var weightEstimate input.TxWeightEstimator
 		tx := wire.NewMsgTx(1)
 
 		for j := 0; j < test.numP2PKHInputs; j++ {

lnwallet/test_utils.go

@@ -6,19 +6,17 @@ import (
 	"crypto/sha256"
 	"encoding/binary"
 	"encoding/hex"
-	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"sync"
 
 	"github.com/btcsuite/btcd/btcec"
-	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/shachain"
@@ -143,7 +141,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 			MaxPendingAmount: lnwire.NewMSatFromSatoshis(channelCapacity),
 			ChanReserve:      channelCapacity / 100,
 			MinHTLC:          0,
-			MaxAcceptedHtlcs: MaxHTLCNumber / 2,
+			MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 			CsvDelay:         uint16(csvTimeoutAlice),
 		},
 		MultiSigKey: keychain.KeyDescriptor{
@@ -168,7 +166,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 			MaxPendingAmount: lnwire.NewMSatFromSatoshis(channelCapacity),
 			ChanReserve:      channelCapacity / 100,
 			MinHTLC:          0,
-			MaxAcceptedHtlcs: MaxHTLCNumber / 2,
+			MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 			CsvDelay:         uint16(csvTimeoutBob),
 		},
 		MultiSigKey: keychain.KeyDescriptor{
@@ -197,7 +195,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	bobCommitPoint := ComputeCommitmentPoint(bobFirstRevoke[:])
+	bobCommitPoint := input.ComputeCommitmentPoint(bobFirstRevoke[:])
 
 	aliceRoot, err := chainhash.NewHash(aliceKeys[0].Serialize())
 	if err != nil {
@@ -208,7 +206,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	aliceCommitPoint := ComputeCommitmentPoint(aliceFirstRevoke[:])
+	aliceCommitPoint := input.ComputeCommitmentPoint(aliceFirstRevoke[:])
 
 	aliceCommitTx, bobCommitTx, err := CreateCommitmentTxns(channelBal,
 		channelBal, &aliceCfg, &bobCfg, aliceCommitPoint, bobCommitPoint,
@@ -300,8 +298,8 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 		Packager:                channeldb.NewChannelPackager(shortChanID),
 	}
 
-	aliceSigner := &mockSigner{privkeys: aliceKeys}
-	bobSigner := &mockSigner{privkeys: bobKeys}
+	aliceSigner := &input.MockSigner{Privkeys: aliceKeys}
+	bobSigner := &input.MockSigner{Privkeys: bobKeys}
 
 	pCache := &mockPreimageCache{
 		// hash -> preimage
@@ -389,118 +387,6 @@ func initRevocationWindows(chanA, chanB *LightningChannel) error {
 	return nil
 }
 
-// mockSigner is a simple implementation of the Signer interface. Each one has
-// a set of private keys in a slice and can sign messages using the appropriate
-// one.
-type mockSigner struct {
-	privkeys  []*btcec.PrivateKey
-	netParams *chaincfg.Params
-}
-
-func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *SignDescriptor) ([]byte, error) {
-	pubkey := signDesc.KeyDesc.PubKey
-	switch {
-	case signDesc.SingleTweak != nil:
-		pubkey = TweakPubKeyWithTweak(pubkey, signDesc.SingleTweak)
-	case signDesc.DoubleTweak != nil:
-		pubkey = DeriveRevocationPubkey(pubkey, signDesc.DoubleTweak.PubKey())
-	}
-
-	hash160 := btcutil.Hash160(pubkey.SerializeCompressed())
-	privKey := m.findKey(hash160, signDesc.SingleTweak, signDesc.DoubleTweak)
-	if privKey == nil {
-		return nil, fmt.Errorf("Mock signer does not have key")
-	}
-
-	sig, err := txscript.RawTxInWitnessSignature(tx, signDesc.SigHashes,
-		signDesc.InputIndex, signDesc.Output.Value, signDesc.WitnessScript,
-		txscript.SigHashAll, privKey)
-	if err != nil {
-		return nil, err
-	}
-
-	return sig[:len(sig)-1], nil
-}
-
-func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*InputScript, error) {
-	scriptType, addresses, _, err := txscript.ExtractPkScriptAddrs(
-		signDesc.Output.PkScript, m.netParams)
-	if err != nil {
-		return nil, err
-	}
-
-	switch scriptType {
-	case txscript.PubKeyHashTy:
-		privKey := m.findKey(addresses[0].ScriptAddress(), signDesc.SingleTweak,
-			signDesc.DoubleTweak)
-		if privKey == nil {
-			return nil, fmt.Errorf("Mock signer does not have key for "+
-				"address %v", addresses[0])
-		}
-
-		sigScript, err := txscript.SignatureScript(
-			tx, signDesc.InputIndex, signDesc.Output.PkScript,
-			txscript.SigHashAll, privKey, true,
-		)
-		if err != nil {
-			return nil, err
-		}
-
-		return &InputScript{SigScript: sigScript}, nil
-
-	case txscript.WitnessV0PubKeyHashTy:
-		privKey := m.findKey(addresses[0].ScriptAddress(), signDesc.SingleTweak,
-			signDesc.DoubleTweak)
-		if privKey == nil {
-			return nil, fmt.Errorf("Mock signer does not have key for "+
-				"address %v", addresses[0])
-		}
-
-		witnessScript, err := txscript.WitnessSignature(tx, signDesc.SigHashes,
-			signDesc.InputIndex, signDesc.Output.Value,
-			signDesc.Output.PkScript, txscript.SigHashAll, privKey, true)
-		if err != nil {
-			return nil, err
-		}
-
-		return &InputScript{Witness: witnessScript}, nil
-
-	default:
-		return nil, fmt.Errorf("Unexpected script type: %v", scriptType)
-	}
-}
-
-// findKey searches through all stored private keys and returns one
-// corresponding to the hashed pubkey if it can be found. The public key may
-// either correspond directly to the private key or to the private key with a
-// tweak applied.
-func (m *mockSigner) findKey(needleHash160 []byte, singleTweak []byte,
-	doubleTweak *btcec.PrivateKey) *btcec.PrivateKey {
-
-	for _, privkey := range m.privkeys {
-		// First check whether public key is directly derived from private key.
-		hash160 := btcutil.Hash160(privkey.PubKey().SerializeCompressed())
-		if bytes.Equal(hash160, needleHash160) {
-			return privkey
-		}
-
-		// Otherwise check if public key is derived from tweaked private key.
-		switch {
-		case singleTweak != nil:
-			privkey = TweakPrivKey(privkey, singleTweak)
-		case doubleTweak != nil:
-			privkey = DeriveRevocationPrivKey(privkey, doubleTweak)
-		default:
-			continue
-		}
-		hash160 = btcutil.Hash160(privkey.PubKey().SerializeCompressed())
-		if bytes.Equal(hash160, needleHash160) {
-			return privkey
-		}
-	}
-	return nil
-}
-
 type mockPreimageCache struct {
 	sync.Mutex
 	preimageMap map[[32]byte][]byte

lnwallet/transactions.go

@@ -0,0 +1,202 @@
+package lnwallet
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/input"
+)
+
+const (
+	// StateHintSize is the total number of bytes used between the sequence
+	// number and locktime of the commitment transaction use to encode a hint
+	// to the state number of a particular commitment transaction.
+	StateHintSize = 6
+
+	// MaxStateHint is the maximum state number we're able to encode using
+	// StateHintSize bytes amongst the sequence number and locktime fields
+	// of the commitment transaction.
+	maxStateHint uint64 = (1 << 48) - 1
+)
+
+var (
+	// TimelockShift is used to make sure the commitment transaction is
+	// spendable by setting the locktime with it so that it is larger than
+	// 500,000,000, thus interpreting it as Unix epoch timestamp and not
+	// a block height. It is also smaller than the current timestamp which
+	// has bit (1 << 30) set, so there is no risk of having the commitment
+	// transaction be rejected. This way we can safely use the lower 24 bits
+	// of the locktime field for part of the obscured commitment transaction
+	// number.
+	TimelockShift = uint32(1 << 29)
+)
+
+// createHtlcSuccessTx creates a transaction that spends the output on the
+// commitment transaction of the peer that receives an HTLC. This transaction
+// essentially acts as an off-chain covenant as it's only permitted to spend
+// the designated HTLC output, and also that spend can _only_ be used as a
+// state transition to create another output which actually allows redemption
+// or revocation of an HTLC.
+//
+// In order to spend the HTLC output, the witness for the passed transaction
+// should be:
+//   * <0> <sender sig> <recvr sig> <preimage>
+func createHtlcSuccessTx(htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
+	csvDelay uint32,
+	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
+
+	// Create a version two transaction (as the success version of this
+	// spends an output with a CSV timeout).
+	successTx := wire.NewMsgTx(2)
+
+	// The input to the transaction is the outpoint that creates the
+	// original HTLC on the sender's commitment transaction.
+	successTx.AddTxIn(&wire.TxIn{
+		PreviousOutPoint: htlcOutput,
+	})
+
+	// Next, we'll generate the script used as the output for all second
+	// level HTLC which forces a covenant w.r.t what can be done with all
+	// HTLC outputs.
+	witnessScript, err := input.SecondLevelHtlcScript(revocationKey, delayKey,
+		csvDelay)
+	if err != nil {
+		return nil, err
+	}
+	pkScript, err := input.WitnessScriptHash(witnessScript)
+	if err != nil {
+		return nil, err
+	}
+
+	// Finally, the output is simply the amount of the HTLC (minus the
+	// required fees), paying to the timeout script.
+	successTx.AddTxOut(&wire.TxOut{
+		Value:    int64(htlcAmt),
+		PkScript: pkScript,
+	})
+
+	return successTx, nil
+}
+
+// createHtlcTimeoutTx creates a transaction that spends the HTLC output on the
+// commitment transaction of the peer that created an HTLC (the sender). This
+// transaction essentially acts as an off-chain covenant as it spends a 2-of-2
+// multi-sig output. This output requires a signature from both the sender and
+// receiver of the HTLC. By using a distinct transaction, we're able to
+// uncouple the timeout and delay clauses of the HTLC contract. This
+// transaction is locked with an absolute lock-time so the sender can only
+// attempt to claim the output using it after the lock time has passed.
+//
+// In order to spend the HTLC output, the witness for the passed transaction
+// should be:
+// * <0> <sender sig> <receiver sig> <0>
+//
+// NOTE: The passed amount for the HTLC should take into account the required
+// fee rate at the time the HTLC was created. The fee should be able to
+// entirely pay for this (tiny: 1-in 1-out) transaction.
+func createHtlcTimeoutTx(htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
+	cltvExpiry, csvDelay uint32,
+	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
+
+	// Create a version two transaction (as the success version of this
+	// spends an output with a CSV timeout), and set the lock-time to the
+	// specified absolute lock-time in blocks.
+	timeoutTx := wire.NewMsgTx(2)
+	timeoutTx.LockTime = cltvExpiry
+
+	// The input to the transaction is the outpoint that creates the
+	// original HTLC on the sender's commitment transaction.
+	timeoutTx.AddTxIn(&wire.TxIn{
+		PreviousOutPoint: htlcOutput,
+	})
+
+	// Next, we'll generate the script used as the output for all second
+	// level HTLC which forces a covenant w.r.t what can be done with all
+	// HTLC outputs.
+	witnessScript, err := input.SecondLevelHtlcScript(revocationKey, delayKey,
+		csvDelay)
+	if err != nil {
+		return nil, err
+	}
+	pkScript, err := input.WitnessScriptHash(witnessScript)
+	if err != nil {
+		return nil, err
+	}
+
+	// Finally, the output is simply the amount of the HTLC (minus the
+	// required fees), paying to the regular second level HTLC script.
+	timeoutTx.AddTxOut(&wire.TxOut{
+		Value:    int64(htlcAmt),
+		PkScript: pkScript,
+	})
+
+	return timeoutTx, nil
+}
+
+// SetStateNumHint encodes the current state number within the passed
+// commitment transaction by re-purposing the locktime and sequence fields in
+// the commitment transaction to encode the obfuscated state number.  The state
+// number is encoded using 48 bits. The lower 24 bits of the lock time are the
+// lower 24 bits of the obfuscated state number and the lower 24 bits of the
+// sequence field are the higher 24 bits. Finally before encoding, the
+// obfuscator is XOR'd against the state number in order to hide the exact
+// state number from the PoV of outside parties.
+func SetStateNumHint(commitTx *wire.MsgTx, stateNum uint64,
+	obfuscator [StateHintSize]byte) error {
+
+	// With the current schema we are only able to encode state num
+	// hints up to 2^48. Therefore if the passed height is greater than our
+	// state hint ceiling, then exit early.
+	if stateNum > maxStateHint {
+		return fmt.Errorf("unable to encode state, %v is greater "+
+			"state num that max of %v", stateNum, maxStateHint)
+	}
+
+	if len(commitTx.TxIn) != 1 {
+		return fmt.Errorf("commitment tx must have exactly 1 input, "+
+			"instead has %v", len(commitTx.TxIn))
+	}
+
+	// Convert the obfuscator into a uint64, then XOR that against the
+	// targeted height in order to obfuscate the state number of the
+	// commitment transaction in the case that either commitment
+	// transaction is broadcast directly on chain.
+	var obfs [8]byte
+	copy(obfs[2:], obfuscator[:])
+	xorInt := binary.BigEndian.Uint64(obfs[:])
+
+	stateNum = stateNum ^ xorInt
+
+	// Set the height bit of the sequence number in order to disable any
+	// sequence locks semantics.
+	commitTx.TxIn[0].Sequence = uint32(stateNum>>24) | wire.SequenceLockTimeDisabled
+	commitTx.LockTime = uint32(stateNum&0xFFFFFF) | TimelockShift
+
+	return nil
+}
+
+// GetStateNumHint recovers the current state number given a commitment
+// transaction which has previously had the state number encoded within it via
+// setStateNumHint and a shared obfuscator.
+//
+// See setStateNumHint for further details w.r.t exactly how the state-hints
+// are encoded.
+func GetStateNumHint(commitTx *wire.MsgTx, obfuscator [StateHintSize]byte) uint64 {
+	// Convert the obfuscator into a uint64, this will be used to
+	// de-obfuscate the final recovered state number.
+	var obfs [8]byte
+	copy(obfs[2:], obfuscator[:])
+	xorInt := binary.BigEndian.Uint64(obfs[:])
+
+	// Retrieve the state hint from the sequence number and locktime
+	// of the transaction.
+	stateNumXor := uint64(commitTx.TxIn[0].Sequence&0xFFFFFF) << 24
+	stateNumXor |= uint64(commitTx.LockTime & 0xFFFFFF)
+
+	// Finally, to obtain the final state number, we XOR by the obfuscator
+	// value to de-obfuscate the state number.
+	return stateNumXor ^ xorInt
+}

lnwallet/transactions_test.go

@@ -5,14 +5,17 @@ import (
 	"encoding/hex"
 	"fmt"
 	"testing"
+	"time"
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/shachain"
@@ -378,7 +381,7 @@ func TestCommitmentAndHTLCTransactions(t *testing.T) {
 			ChannelConstraints: channeldb.ChannelConstraints{
 				DustLimit:        tc.dustLimit,
 				MaxPendingAmount: lnwire.NewMSatFromSatoshis(tc.fundingAmount),
-				MaxAcceptedHtlcs: MaxHTLCNumber,
+				MaxAcceptedHtlcs: input.MaxHTLCNumber,
 				CsvDelay:         tc.localCsvDelay,
 			},
 			MultiSigKey: keychain.KeyDescriptor{
@@ -408,11 +411,11 @@ func TestCommitmentAndHTLCTransactions(t *testing.T) {
 		Capacity:           tc.fundingAmount,
 		RevocationProducer: shachain.NewRevocationProducer(zeroHash),
 	}
-	signer := &mockSigner{
-		privkeys: []*btcec.PrivateKey{
+	signer := &input.MockSigner{
+		Privkeys: []*btcec.PrivateKey{
 			tc.localFundingPrivKey, tc.localPaymentPrivKey,
 		},
-		netParams: tc.netParams,
+		NetParams: tc.netParams,
 	}
 
 	// Construct a LightningChannel manually because we don't have nor need all
@@ -431,7 +434,7 @@ func TestCommitmentAndHTLCTransactions(t *testing.T) {
 
 	// The commitmentPoint is technically hidden in the spec, but we need it to
 	// generate the correct tweak.
-	tweak := SingleTweakBytes(tc.commitmentPoint, tc.localPaymentBasePoint)
+	tweak := input.SingleTweakBytes(tc.commitmentPoint, tc.localPaymentBasePoint)
 	keys := &CommitmentKeyRing{
 		CommitPoint:         tc.commitmentPoint,
 		LocalCommitKeyTweak: tweak,
@@ -910,3 +913,299 @@ func htlcViewFromHTLCs(htlcs []channeldb.HTLC) *htlcView {
 	}
 	return &theHTLCView
 }
+
+func TestCommitTxStateHint(t *testing.T) {
+	t.Parallel()
+
+	stateHintTests := []struct {
+		name       string
+		from       uint64
+		to         uint64
+		inputs     int
+		shouldFail bool
+	}{
+		{
+			name:       "states 0 to 1000",
+			from:       0,
+			to:         1000,
+			inputs:     1,
+			shouldFail: false,
+		},
+		{
+			name:       "states 'maxStateHint-1000' to 'maxStateHint'",
+			from:       maxStateHint - 1000,
+			to:         maxStateHint,
+			inputs:     1,
+			shouldFail: false,
+		},
+		{
+			name:       "state 'maxStateHint+1'",
+			from:       maxStateHint + 1,
+			to:         maxStateHint + 10,
+			inputs:     1,
+			shouldFail: true,
+		},
+		{
+			name:       "commit transaction with two inputs",
+			inputs:     2,
+			shouldFail: true,
+		},
+	}
+
+	var obfuscator [StateHintSize]byte
+	copy(obfuscator[:], testHdSeed[:StateHintSize])
+	timeYesterday := uint32(time.Now().Unix() - 24*60*60)
+
+	for _, test := range stateHintTests {
+		commitTx := wire.NewMsgTx(2)
+
+		// Add supplied number of inputs to the commitment transaction.
+		for i := 0; i < test.inputs; i++ {
+			commitTx.AddTxIn(&wire.TxIn{})
+		}
+
+		for i := test.from; i <= test.to; i++ {
+			stateNum := uint64(i)
+
+			err := SetStateNumHint(commitTx, stateNum, obfuscator)
+			if err != nil && !test.shouldFail {
+				t.Fatalf("unable to set state num %v: %v", i, err)
+			} else if err == nil && test.shouldFail {
+				t.Fatalf("Failed(%v): test should fail but did not", test.name)
+			}
+
+			locktime := commitTx.LockTime
+			sequence := commitTx.TxIn[0].Sequence
+
+			// Locktime should not be less than 500,000,000 and not larger
+			// than the time 24 hours ago. One day should provide a good
+			// enough buffer for the tests.
+			if locktime < 5e8 || locktime > timeYesterday {
+				if !test.shouldFail {
+					t.Fatalf("The value of locktime (%v) may cause the commitment "+
+						"transaction to be unspendable", locktime)
+				}
+			}
+
+			if sequence&wire.SequenceLockTimeDisabled == 0 {
+				if !test.shouldFail {
+					t.Fatalf("Sequence locktime is NOT disabled when it should be")
+				}
+			}
+
+			extractedStateNum := GetStateNumHint(commitTx, obfuscator)
+			if extractedStateNum != stateNum && !test.shouldFail {
+				t.Fatalf("state number mismatched, expected %v, got %v",
+					stateNum, extractedStateNum)
+			} else if extractedStateNum == stateNum && test.shouldFail {
+				t.Fatalf("Failed(%v): test should fail but did not", test.name)
+			}
+		}
+		t.Logf("Passed: %v", test.name)
+	}
+}
+
+// TestCommitmentSpendValidation test the spendability of both outputs within
+// the commitment transaction.
+//
+// The following spending cases are covered by this test:
+//   * Alice's spend from the delayed output on her commitment transaction.
+//   * Bob's spend from Alice's delayed output when she broadcasts a revoked
+//     commitment transaction.
+//   * Bob's spend from his unencumbered output within Alice's commitment
+//     transaction.
+func TestCommitmentSpendValidation(t *testing.T) {
+	t.Parallel()
+
+	// We generate a fake output, and the corresponding txin. This output
+	// doesn't need to exist, as we'll only be validating spending from the
+	// transaction that references this.
+	txid, err := chainhash.NewHash(testHdSeed.CloneBytes())
+	if err != nil {
+		t.Fatalf("unable to create txid: %v", err)
+	}
+	fundingOut := &wire.OutPoint{
+		Hash:  *txid,
+		Index: 50,
+	}
+	fakeFundingTxIn := wire.NewTxIn(fundingOut, nil, nil)
+
+	const channelBalance = btcutil.Amount(1 * 10e8)
+	const csvTimeout = uint32(5)
+
+	// We also set up set some resources for the commitment transaction.
+	// Each side currently has 1 BTC within the channel, with a total
+	// channel capacity of 2BTC.
+	aliceKeyPriv, aliceKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
+		testWalletPrivKey)
+	bobKeyPriv, bobKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
+		bobsPrivKey)
+
+	revocationPreimage := testHdSeed.CloneBytes()
+	commitSecret, commitPoint := btcec.PrivKeyFromBytes(btcec.S256(),
+		revocationPreimage)
+	revokePubKey := input.DeriveRevocationPubkey(bobKeyPub, commitPoint)
+
+	aliceDelayKey := input.TweakPubKey(aliceKeyPub, commitPoint)
+	bobPayKey := input.TweakPubKey(bobKeyPub, commitPoint)
+
+	aliceCommitTweak := input.SingleTweakBytes(commitPoint, aliceKeyPub)
+	bobCommitTweak := input.SingleTweakBytes(commitPoint, bobKeyPub)
+
+	aliceSelfOutputSigner := &input.MockSigner{
+		Privkeys: []*btcec.PrivateKey{aliceKeyPriv},
+	}
+
+	// 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
+	// identical with the roles reversed.
+	//
+	// 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.
+	keyRing := &CommitmentKeyRing{
+		DelayKey:      aliceDelayKey,
+		RevocationKey: revokePubKey,
+		NoDelayKey:    bobPayKey,
+	}
+	commitmentTx, err := CreateCommitTx(*fakeFundingTxIn, keyRing, csvTimeout,
+		channelBalance, channelBalance, DefaultDustLimit())
+	if err != nil {
+		t.Fatalf("unable to create commitment transaction: %v", nil)
+	}
+
+	delayOutput := commitmentTx.TxOut[0]
+	regularOutput := commitmentTx.TxOut[1]
+
+	// We're testing an uncooperative close, output sweep, so construct a
+	// transaction which sweeps the funds to a random address.
+	targetOutput, err := input.CommitScriptUnencumbered(aliceKeyPub)
+	if err != nil {
+		t.Fatalf("unable to create target output: %v", err)
+	}
+	sweepTx := wire.NewMsgTx(2)
+	sweepTx.AddTxIn(wire.NewTxIn(&wire.OutPoint{
+		Hash:  commitmentTx.TxHash(),
+		Index: 0,
+	}, nil, nil))
+	sweepTx.AddTxOut(&wire.TxOut{
+		PkScript: targetOutput,
+		Value:    0.5 * 10e8,
+	})
+
+	// First, we'll test spending with Alice's key after the timeout.
+	delayScript, err := input.CommitScriptToSelf(csvTimeout, aliceDelayKey,
+		revokePubKey)
+	if err != nil {
+		t.Fatalf("unable to generate alice delay script: %v", err)
+	}
+	sweepTx.TxIn[0].Sequence = input.LockTimeToSequence(false, csvTimeout)
+	signDesc := &input.SignDescriptor{
+		WitnessScript: delayScript,
+		KeyDesc: keychain.KeyDescriptor{
+			PubKey: aliceKeyPub,
+		},
+		SingleTweak: aliceCommitTweak,
+		SigHashes:   txscript.NewTxSigHashes(sweepTx),
+		Output: &wire.TxOut{
+			Value: int64(channelBalance),
+		},
+		HashType:   txscript.SigHashAll,
+		InputIndex: 0,
+	}
+	aliceWitnessSpend, err := input.CommitSpendTimeout(aliceSelfOutputSigner,
+		signDesc, sweepTx)
+	if err != nil {
+		t.Fatalf("unable to generate delay commit spend witness: %v", err)
+	}
+	sweepTx.TxIn[0].Witness = aliceWitnessSpend
+	vm, err := txscript.NewEngine(delayOutput.PkScript,
+		sweepTx, 0, txscript.StandardVerifyFlags, nil,
+		nil, int64(channelBalance))
+	if err != nil {
+		t.Fatalf("unable to create engine: %v", err)
+	}
+	if err := vm.Execute(); err != nil {
+		t.Fatalf("spend from delay output is invalid: %v", err)
+	}
+
+	bobSigner := &input.MockSigner{Privkeys: []*btcec.PrivateKey{bobKeyPriv}}
+
+	// Next, we'll test bob spending with the derived revocation key to
+	// simulate the scenario when Alice broadcasts this commitment
+	// transaction after it's been revoked.
+	signDesc = &input.SignDescriptor{
+		KeyDesc: keychain.KeyDescriptor{
+			PubKey: bobKeyPub,
+		},
+		DoubleTweak:   commitSecret,
+		WitnessScript: delayScript,
+		SigHashes:     txscript.NewTxSigHashes(sweepTx),
+		Output: &wire.TxOut{
+			Value: int64(channelBalance),
+		},
+		HashType:   txscript.SigHashAll,
+		InputIndex: 0,
+	}
+	bobWitnessSpend, err := input.CommitSpendRevoke(bobSigner, signDesc,
+		sweepTx)
+	if err != nil {
+		t.Fatalf("unable to generate revocation witness: %v", err)
+	}
+	sweepTx.TxIn[0].Witness = bobWitnessSpend
+	vm, err = txscript.NewEngine(delayOutput.PkScript,
+		sweepTx, 0, txscript.StandardVerifyFlags, nil,
+		nil, int64(channelBalance))
+	if err != nil {
+		t.Fatalf("unable to create engine: %v", err)
+	}
+	if err := vm.Execute(); err != nil {
+		t.Fatalf("revocation spend is invalid: %v", err)
+	}
+
+	// In order to test the final scenario, we modify the TxIn of the sweep
+	// transaction to instead point to the regular output (non delay)
+	// within the commitment transaction.
+	sweepTx.TxIn[0] = &wire.TxIn{
+		PreviousOutPoint: wire.OutPoint{
+			Hash:  commitmentTx.TxHash(),
+			Index: 1,
+		},
+	}
+
+	// Finally, we test bob sweeping his output as normal in the case that
+	// Alice broadcasts this commitment transaction.
+	bobScriptP2WKH, err := input.CommitScriptUnencumbered(bobPayKey)
+	if err != nil {
+		t.Fatalf("unable to create bob p2wkh script: %v", err)
+	}
+	signDesc = &input.SignDescriptor{
+		KeyDesc: keychain.KeyDescriptor{
+			PubKey: bobKeyPub,
+		},
+		SingleTweak:   bobCommitTweak,
+		WitnessScript: bobScriptP2WKH,
+		SigHashes:     txscript.NewTxSigHashes(sweepTx),
+		Output: &wire.TxOut{
+			Value:    int64(channelBalance),
+			PkScript: bobScriptP2WKH,
+		},
+		HashType:   txscript.SigHashAll,
+		InputIndex: 0,
+	}
+	bobRegularSpend, err := input.CommitSpendNoDelay(bobSigner, signDesc,
+		sweepTx)
+	if err != nil {
+		t.Fatalf("unable to create bob regular spend: %v", err)
+	}
+	sweepTx.TxIn[0].Witness = bobRegularSpend
+	vm, err = txscript.NewEngine(regularOutput.PkScript,
+		sweepTx, 0, txscript.StandardVerifyFlags, nil,
+		nil, int64(channelBalance))
+	if err != nil {
+		t.Fatalf("unable to create engine: %v", err)
+	}
+	if err := vm.Execute(); err != nil {
+		t.Fatalf("bob p2wkh spend is invalid: %v", err)
+	}
+}

lnwallet/txout.go

@@ -1,46 +0,0 @@
-package lnwallet
-
-import (
-	"encoding/binary"
-	"io"
-
-	"github.com/btcsuite/btcd/wire"
-)
-
-// writeTxOut serializes a wire.TxOut struct into the passed io.Writer stream.
-func writeTxOut(w io.Writer, txo *wire.TxOut) error {
-	var scratch [8]byte
-
-	binary.BigEndian.PutUint64(scratch[:], uint64(txo.Value))
-	if _, err := w.Write(scratch[:]); err != nil {
-		return err
-	}
-
-	if err := wire.WriteVarBytes(w, 0, txo.PkScript); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-// readTxOut deserializes a wire.TxOut struct from the passed io.Reader stream.
-func readTxOut(r io.Reader, txo *wire.TxOut) error {
-	var scratch [8]byte
-
-	if _, err := io.ReadFull(r, scratch[:]); err != nil {
-		return err
-	}
-	value := int64(binary.BigEndian.Uint64(scratch[:]))
-
-	pkScript, err := wire.ReadVarBytes(r, 0, 80, "pkScript")
-	if err != nil {
-		return err
-	}
-
-	*txo = wire.TxOut{
-		Value:    value,
-		PkScript: pkScript,
-	}
-
-	return nil
-}

lnwallet/txout_test.go

@@ -1,46 +0,0 @@
-package lnwallet
-
-import (
-	"bytes"
-	"reflect"
-	"testing"
-
-	"github.com/btcsuite/btcd/wire"
-)
-
-func TestTxOutSerialization(t *testing.T) {
-	txo := wire.TxOut{
-		Value: 1e7,
-		PkScript: []byte{
-			0x41, // OP_DATA_65
-			0x04, 0xd6, 0x4b, 0xdf, 0xd0, 0x9e, 0xb1, 0xc5,
-			0xfe, 0x29, 0x5a, 0xbd, 0xeb, 0x1d, 0xca, 0x42,
-			0x81, 0xbe, 0x98, 0x8e, 0x2d, 0xa0, 0xb6, 0xc1,
-			0xc6, 0xa5, 0x9d, 0xc2, 0x26, 0xc2, 0x86, 0x24,
-			0xe1, 0x81, 0x75, 0xe8, 0x51, 0xc9, 0x6b, 0x97,
-			0x3d, 0x81, 0xb0, 0x1c, 0xc3, 0x1f, 0x04, 0x78,
-			0x34, 0xbc, 0x06, 0xd6, 0xd6, 0xed, 0xf6, 0x20,
-			0xd1, 0x84, 0x24, 0x1a, 0x6a, 0xed, 0x8b, 0x63,
-			0xa6, // 65-byte signature
-			0xac, // OP_CHECKSIG
-		},
-	}
-
-	var buf bytes.Buffer
-
-	if err := writeTxOut(&buf, &txo); err != nil {
-		t.Fatalf("unable to serialize txout: %v", err)
-	}
-
-	var deserializedTxo wire.TxOut
-	if err := readTxOut(&buf, &deserializedTxo); err != nil {
-		t.Fatalf("unable to deserialize txout: %v", err)
-	}
-
-	if !reflect.DeepEqual(txo, deserializedTxo) {
-		t.Fatalf("original and deserialized txouts are different:\n"+
-			"original     : %+v\n"+
-			"deserialized : %+v\n",
-			txo, deserializedTxo)
-	}
-}

lnwallet/wallet.go

@@ -19,6 +19,7 @@ import (
 	"github.com/btcsuite/btcutil/txsort"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/shachain"
@@ -167,7 +168,7 @@ type addCounterPartySigsMsg struct {
 	// Should be order of sorted inputs that are theirs. Sorting is done
 	// in accordance to BIP-69:
 	// https://github.com/bitcoin/bips/blob/master/bip-0069.mediawiki.
-	theirFundingInputScripts []*InputScript
+	theirFundingInputScripts []*input.Script
 
 	// This should be 1/2 of the signatures needed to successfully spend our
 	// version of the commitment transaction.
@@ -562,7 +563,7 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
 		req.resp <- nil
 		return
 	}
-	reservation.ourContribution.FirstCommitmentPoint = ComputeCommitmentPoint(
+	reservation.ourContribution.FirstCommitmentPoint = input.ComputeCommitmentPoint(
 		firstPreimage[:],
 	)
 
@@ -712,7 +713,7 @@ 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)
-	witnessScript, multiSigOut, err := GenFundingPkScript(
+	witnessScript, multiSigOut, err := input.GenFundingPkScript(
 		ourKey.PubKey.SerializeCompressed(),
 		theirKey.PubKey.SerializeCompressed(), channelCapacity,
 	)
@@ -729,9 +730,9 @@ 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,
+	pendingReservation.ourFundingInputScripts = make([]*input.Script, 0,
 		len(ourContribution.Inputs))
-	signDesc := SignDescriptor{
+	signDesc := input.SignDescriptor{
 		HashType:  txscript.SigHashAll,
 		SigHashes: txscript.NewTxSigHashes(fundingTx),
 	}
@@ -767,7 +768,7 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	// since the outputs are canonically sorted. If this is a single funder
 	// workflow, then we'll also need to send this to the remote node.
 	fundingTxID := fundingTx.TxHash()
-	_, multiSigIndex := FindScriptOutputIndex(fundingTx, multiSigOut.PkScript)
+	_, multiSigIndex := input.FindScriptOutputIndex(fundingTx, multiSigOut.PkScript)
 	fundingOutpoint := wire.NewOutPoint(&fundingTxID, multiSigIndex)
 	pendingReservation.partialState.FundingOutpoint = *fundingOutpoint
 
@@ -858,7 +859,7 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 
 	// Generate a signature for their version of the initial commitment
 	// transaction.
-	signDesc = SignDescriptor{
+	signDesc = input.SignDescriptor{
 		WitnessScript: witnessScript,
 		KeyDesc:       ourKey,
 		Output:        multiSigOut,
@@ -966,7 +967,7 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 			//
 			// TODO(roasbeef): when dual funder pass actual
 			// height-hint
-			pkScript, err := WitnessScriptHash(
+			pkScript, err := input.WitnessScriptHash(
 				txin.Witness[len(txin.Witness)-1],
 			)
 			if err != nil {
@@ -1013,7 +1014,7 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 	// Re-generate both the witnessScript and p2sh output. We sign the
 	// witnessScript script, but include the p2sh output as the subscript
 	// for verification.
-	witnessScript, _, err := GenFundingPkScript(
+	witnessScript, _, err := input.GenFundingPkScript(
 		ourKey.PubKey.SerializeCompressed(),
 		theirKey.PubKey.SerializeCompressed(),
 		int64(res.partialState.Capacity),
@@ -1165,7 +1166,7 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 	hashCache := txscript.NewTxSigHashes(ourCommitTx)
 	theirKey := pendingReservation.theirContribution.MultiSigKey
 	ourKey := pendingReservation.ourContribution.MultiSigKey
-	witnessScript, _, err := GenFundingPkScript(
+	witnessScript, _, err := input.GenFundingPkScript(
 		ourKey.PubKey.SerializeCompressed(),
 		theirKey.PubKey.SerializeCompressed(), channelValue,
 	)
@@ -1201,13 +1202,13 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 	// 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.
-	p2wsh, err := WitnessScriptHash(witnessScript)
+	p2wsh, err := input.WitnessScriptHash(witnessScript)
 	if err != nil {
 		req.err <- err
 		req.completeChan <- nil
 		return
 	}
-	signDesc := SignDescriptor{
+	signDesc := input.SignDescriptor{
 		WitnessScript: witnessScript,
 		KeyDesc:       ourKey,
 		Output: &wire.TxOut{
@@ -1401,7 +1402,7 @@ func coinSelect(feeRate SatPerKWeight, amt btcutil.Amount,
 			return nil, 0, err
 		}
 
-		var weightEstimate TxWeightEstimator
+		var weightEstimate input.TxWeightEstimator
 
 		for _, utxo := range selectedUtxos {
 			switch utxo.AddressType {

lnwallet/witnessgen.go

@@ -1,248 +0,0 @@
-package lnwallet
-
-import (
-	"fmt"
-
-	"github.com/btcsuite/btcd/txscript"
-	"github.com/btcsuite/btcd/wire"
-)
-
-// WitnessType determines how an output's witness will be generated. The
-// default commitmentTimeLock type will generate a witness that will allow
-// spending of a time-locked transaction enforced by CheckSequenceVerify.
-type WitnessType uint16
-
-const (
-	// CommitmentTimeLock is a witness that allows us to spend the output of
-	// a commitment transaction after a relative lock-time lockout.
-	CommitmentTimeLock WitnessType = 0
-
-	// CommitmentNoDelay is a witness that allows us to spend a settled
-	// no-delay output immediately on a counterparty's commitment
-	// transaction.
-	CommitmentNoDelay WitnessType = 1
-
-	// CommitmentRevoke is a witness that allows us to sweep the settled
-	// output of a malicious counterparty's who broadcasts a revoked
-	// commitment transaction.
-	CommitmentRevoke WitnessType = 2
-
-	// HtlcOfferedRevoke is a witness that allows us to sweep an HTLC which
-	// we offered to the remote party in the case that they broadcast a
-	// revoked commitment state.
-	HtlcOfferedRevoke WitnessType = 3
-
-	// HtlcAcceptedRevoke is a witness that allows us to sweep an HTLC
-	// output sent to us in the case that the remote party broadcasts a
-	// revoked commitment state.
-	HtlcAcceptedRevoke WitnessType = 4
-
-	// HtlcOfferedTimeoutSecondLevel is a witness that allows us to sweep
-	// an HTLC output that we extended to a party, but was never fulfilled.
-	// This HTLC output isn't directly on the commitment transaction, but
-	// is the result of a confirmed second-level HTLC transaction. As a
-	// result, we can only spend this after a CSV delay.
-	HtlcOfferedTimeoutSecondLevel WitnessType = 5
-
-	// HtlcAcceptedSuccessSecondLevel is a witness that allows us to sweep
-	// an HTLC output that was offered to us, and for which we have a
-	// payment preimage. This HTLC output isn't directly on our commitment
-	// transaction, but is the result of confirmed second-level HTLC
-	// transaction. As a result, we can only spend this after a CSV delay.
-	HtlcAcceptedSuccessSecondLevel WitnessType = 6
-
-	// HtlcOfferedRemoteTimeout is a witness that allows us to sweep an
-	// HTLC that we offered to the remote party which lies in the
-	// commitment transaction of the remote party. We can spend this output
-	// after the absolute CLTV timeout of the HTLC as passed.
-	HtlcOfferedRemoteTimeout WitnessType = 7
-
-	// HtlcAcceptedRemoteSuccess is a witness that allows us to sweep an
-	// HTLC that was offered to us by the remote party. We use this witness
-	// in the case that the remote party goes to chain, and we know the
-	// pre-image to the HTLC. We can sweep this without any additional
-	// timeout.
-	HtlcAcceptedRemoteSuccess WitnessType = 8
-
-	// HtlcSecondLevelRevoke is a witness that allows us to sweep an HTLC
-	// from the remote party's commitment transaction in the case that the
-	// broadcast a revoked commitment, but then also immediately attempt to
-	// go to the second level to claim the HTLC.
-	HtlcSecondLevelRevoke WitnessType = 9
-
-	// WitnessKeyHash is a witness type that allows us to spend a regular
-	// p2wkh output that's sent to an output which is under complete
-	// control of the backing wallet.
-	WitnessKeyHash WitnessType = 10
-
-	// NestedWitnessKeyHash is a witness type that allows us to sweep an
-	// output that sends to a nested P2SH script that pays to a key solely
-	// under our control. The witness generated needs to include the
-	NestedWitnessKeyHash WitnessType = 11
-)
-
-// Stirng returns a human readable version of the target WitnessType.
-func (wt WitnessType) String() string {
-	switch wt {
-	case CommitmentTimeLock:
-		return "CommitmentTimeLock"
-
-	case CommitmentNoDelay:
-		return "CommitmentNoDelay"
-
-	case CommitmentRevoke:
-		return "CommitmentRevoke"
-
-	case HtlcOfferedRevoke:
-		return "HtlcOfferedRevoke"
-
-	case HtlcAcceptedRevoke:
-		return "HtlcAcceptedRevoke"
-
-	case HtlcOfferedTimeoutSecondLevel:
-		return "HtlcOfferedTimeoutSecondLevel"
-
-	case HtlcAcceptedSuccessSecondLevel:
-		return "HtlcAcceptedSuccessSecondLevel"
-
-	case HtlcOfferedRemoteTimeout:
-		return "HtlcOfferedRemoteTimeout"
-
-	case HtlcAcceptedRemoteSuccess:
-		return "HtlcAcceptedRemoteSuccess"
-
-	case HtlcSecondLevelRevoke:
-		return "HtlcSecondLevelRevoke"
-
-	default:
-		return fmt.Sprintf("Unknown WitnessType: %v", uint32(wt))
-	}
-}
-
-// WitnessGenerator represents a function which is able to generate the final
-// witness for a particular public key script. Additionally, if required, this
-// function will also return the sigScript for spending nested P2SH witness
-// outputs. This function acts as an abstraction layer, hiding the details of
-// the underlying script.
-type WitnessGenerator func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
-	inputIndex int) (*InputScript, error)
-
-// GenWitnessFunc will return a WitnessGenerator function that an output uses
-// to generate the witness and optionally the sigScript for a sweep
-// transaction. The sigScript will be generated if the witness type warrants
-// one for spending, such as the NestedWitnessKeyHash witness type.
-func (wt WitnessType) GenWitnessFunc(signer Signer,
-	descriptor *SignDescriptor) WitnessGenerator {
-
-	return func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
-		inputIndex int) (*InputScript, error) {
-
-		desc := descriptor
-		desc.SigHashes = hc
-		desc.InputIndex = inputIndex
-
-		switch wt {
-		case CommitmentTimeLock:
-			witness, err := CommitSpendTimeout(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case CommitmentNoDelay:
-			witness, err := CommitSpendNoDelay(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case CommitmentRevoke:
-			witness, err := CommitSpendRevoke(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case HtlcOfferedRevoke:
-			witness, err := ReceiverHtlcSpendRevoke(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case HtlcAcceptedRevoke:
-			witness, err := SenderHtlcSpendRevoke(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case HtlcOfferedTimeoutSecondLevel:
-			witness, err := HtlcSecondLevelSpend(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case HtlcAcceptedSuccessSecondLevel:
-			witness, err := HtlcSecondLevelSpend(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case HtlcOfferedRemoteTimeout:
-			// We pass in a value of -1 for the timeout, as we
-			// expect the caller to have already set the lock time
-			// value.
-			witness, err := receiverHtlcSpendTimeout(signer, desc, tx, -1)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case HtlcSecondLevelRevoke:
-			witness, err := htlcSpendRevoke(signer, desc, tx)
-			if err != nil {
-				return nil, err
-			}
-
-			return &InputScript{
-				Witness: witness,
-			}, nil
-
-		case WitnessKeyHash:
-			fallthrough
-		case NestedWitnessKeyHash:
-			return signer.ComputeInputScript(tx, desc)
-
-		default:
-			return nil, fmt.Errorf("unknown witness type: %v", wt)
-		}
-	}
-
-}