lnwallet: support transactions and scripts for new commitment type

This commit modifies the channel state machine to be able to derive the
proper commitment and second-level HTLC output scripts required by the
new script-enforced leased channel commitment type.

contractcourt/breacharbiter_test.go

@@ -2299,6 +2299,7 @@ func createInitChannels(revocationWindow int) (*lnwallet.LightningChannel, *lnwa
 	aliceCommitTx, bobCommitTx, err := lnwallet.CreateCommitmentTxns(
 		channelBal, channelBal, &aliceCfg, &bobCfg, aliceCommitPoint,
 		bobCommitPoint, *fundingTxIn, channeldb.SingleFunderTweaklessBit,
+		false, 0,
 	)
 	if err != nil {
 		return nil, nil, nil, err

contractcourt/chain_watcher.go

@@ -362,8 +362,13 @@ func (c *chainWatcher) handleUnknownLocalState(
 
 	// With the keys derived, we'll construct the remote script that'll be
 	// present if they have a non-dust balance on the commitment.
+	var leaseExpiry uint32
+	if c.cfg.chanState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = c.cfg.chanState.ThawHeight
+	}
 	remoteScript, _, err := lnwallet.CommitScriptToRemote(
-		c.cfg.chanState.ChanType, commitKeyRing.ToRemoteKey,
+		c.cfg.chanState.ChanType, c.cfg.chanState.IsInitiator,
+		commitKeyRing.ToRemoteKey, leaseExpiry,
 	)
 	if err != nil {
 		return false, err
@@ -373,8 +378,9 @@ func (c *chainWatcher) handleUnknownLocalState(
 	// the remote party allowing them to claim this output before the CSV
 	// delay if we breach.
 	localScript, err := lnwallet.CommitScriptToSelf(
+		c.cfg.chanState.ChanType, c.cfg.chanState.IsInitiator,
 		commitKeyRing.ToLocalKey, commitKeyRing.RevocationKey,
-		uint32(c.cfg.chanState.LocalChanCfg.CsvDelay),
+		uint32(c.cfg.chanState.LocalChanCfg.CsvDelay), leaseExpiry,
 	)
 	if err != nil {
 		return false, err

htlcswitch/test_utils.go

@@ -134,6 +134,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 	channelCapacity := aliceAmount + bobAmount
 	csvTimeoutAlice := uint32(5)
 	csvTimeoutBob := uint32(4)
+	isAliceInitiator := true
 
 	aliceConstraints := &channeldb.ChannelConstraints{
 		DustLimit: btcutil.Amount(200),
@@ -230,6 +231,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 	aliceCommitTx, bobCommitTx, err := lnwallet.CreateCommitmentTxns(
 		aliceAmount, bobAmount, &aliceCfg, &bobCfg, aliceCommitPoint,
 		bobCommitPoint, *fundingTxIn, channeldb.SingleFunderTweaklessBit,
+		isAliceInitiator, 0,
 	)
 	if err != nil {
 		return nil, nil, nil, err
@@ -298,7 +300,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 		IdentityPub:             aliceKeyPub,
 		FundingOutpoint:         *prevOut,
 		ChanType:                channeldb.SingleFunderTweaklessBit,
-		IsInitiator:             true,
+		IsInitiator:             isAliceInitiator,
 		Capacity:                channelCapacity,
 		RemoteCurrentRevocation: bobCommitPoint,
 		RevocationProducer:      alicePreimageProducer,
@@ -317,7 +319,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 		IdentityPub:             bobKeyPub,
 		FundingOutpoint:         *prevOut,
 		ChanType:                channeldb.SingleFunderTweaklessBit,
-		IsInitiator:             false,
+		IsInitiator:             !isAliceInitiator,
 		Capacity:                channelCapacity,
 		RemoteCurrentRevocation: aliceCommitPoint,
 		RevocationProducer:      bobPreimageProducer,

input/size_test.go

@@ -861,8 +861,8 @@ func TestWitnessSizes(t *testing.T) {
 func genTimeoutTx(chanType channeldb.ChannelType) (*wire.MsgTx, error) {
 	// Create the unsigned timeout tx.
 	timeoutTx, err := lnwallet.CreateHtlcTimeoutTx(
-		chanType, testOutPoint, testAmt, testCLTVExpiry,
+		chanType, false, testOutPoint, testAmt, testCLTVExpiry,
-		testCSVDelay, testPubkey, testPubkey,
+		testCSVDelay, 0, testPubkey, testPubkey,
 	)
 	if err != nil {
 		return nil, err
@@ -903,7 +903,7 @@ func genTimeoutTx(chanType channeldb.ChannelType) (*wire.MsgTx, error) {
 func genSuccessTx(chanType channeldb.ChannelType) (*wire.MsgTx, error) {
 	// Create the unisgned success tx.
 	successTx, err := lnwallet.CreateHtlcSuccessTx(
-		chanType, testOutPoint, testAmt, testCSVDelay,
+		chanType, false, testOutPoint, testAmt, testCSVDelay, 0,
 		testPubkey, testPubkey,
 	)
 	if err != nil {

lnwallet/channel.go

@@ -2315,8 +2315,14 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// number so we can have the proper witness script to sign and include
 	// within the final witness.
 	theirDelay := uint32(chanState.RemoteChanCfg.CsvDelay)
+	isRemoteInitiator := !chanState.IsInitiator
+	var leaseExpiry uint32
+	if chanState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = chanState.ThawHeight
+	}
 	theirScript, err := CommitScriptToSelf(
-		keyRing.ToLocalKey, keyRing.RevocationKey, theirDelay,
+		chanState.ChanType, isRemoteInitiator, keyRing.ToLocalKey,
+		keyRing.RevocationKey, theirDelay, leaseExpiry,
 	)
 	if err != nil {
 		return nil, err
@@ -2325,7 +2331,8 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// Since it is the remote breach we are reconstructing, the output going
 	// to us will be a to-remote script with our local params.
 	ourScript, ourDelay, err := CommitScriptToRemote(
-		chanState.ChanType, keyRing.ToRemoteKey,
+		chanState.ChanType, isRemoteInitiator, keyRing.ToRemoteKey,
+		leaseExpiry,
 	)
 	if err != nil {
 		return nil, err
@@ -2410,7 +2417,9 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 		// remote commitment transaction, and *they* go to the second
 		// level.
 		secondLevelScript, err := SecondLevelHtlcScript(
+			chanState.ChanType, isRemoteInitiator,
 			keyRing.RevocationKey, keyRing.ToLocalKey, theirDelay,
+			leaseExpiry,
 		)
 		if err != nil {
 			return nil, err
@@ -2968,8 +2977,8 @@ func processFeeUpdate(feeUpdate *PaymentDescriptor, nextHeight uint64,
 // signature can be submitted to the sigPool to generate all the signatures
 // asynchronously and in parallel.
 func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
-	chanType channeldb.ChannelType,
+	chanType channeldb.ChannelType, isRemoteInitiator bool,
-	localChanCfg, remoteChanCfg *channeldb.ChannelConfig,
+	leaseExpiry uint32, localChanCfg, remoteChanCfg *channeldb.ChannelConfig,
 	remoteCommitView *commitment) ([]SignJob, chan struct{}, error) {
 
 	txHash := remoteCommitView.txn.TxHash()
@@ -3019,9 +3028,9 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 			Index: uint32(htlc.remoteOutputIndex),
 		}
 		sigJob.Tx, err = CreateHtlcTimeoutTx(
-			chanType, op, outputAmt, htlc.Timeout,
+			chanType, isRemoteInitiator, op, outputAmt,
-			uint32(remoteChanCfg.CsvDelay),
+			htlc.Timeout, uint32(remoteChanCfg.CsvDelay),
-			keyRing.RevocationKey, keyRing.ToLocalKey,
+			leaseExpiry, keyRing.RevocationKey, keyRing.ToLocalKey,
 		)
 		if err != nil {
 			return nil, nil, err
@@ -3072,7 +3081,8 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 			Index: uint32(htlc.remoteOutputIndex),
 		}
 		sigJob.Tx, err = CreateHtlcSuccessTx(
-			chanType, op, outputAmt, uint32(remoteChanCfg.CsvDelay),
+			chanType, isRemoteInitiator, op, outputAmt,
+			uint32(remoteChanCfg.CsvDelay), leaseExpiry,
 			keyRing.RevocationKey, keyRing.ToLocalKey,
 		)
 		if err != nil {
@@ -3581,10 +3591,14 @@ func (lc *LightningChannel) SignNextCommitment() (lnwire.Sig, []lnwire.Sig, []ch
 	// need to generate signatures of each of them for the remote party's
 	// commitment state. We do so in two phases: first we generate and
 	// submit the set of signature jobs to the worker pool.
+	var leaseExpiry uint32
+	if lc.channelState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = lc.channelState.ThawHeight
+	}
 	sigBatch, cancelChan, err := genRemoteHtlcSigJobs(
-		keyRing, lc.channelState.ChanType,
+		keyRing, lc.channelState.ChanType, !lc.channelState.IsInitiator,
-		&lc.channelState.LocalChanCfg, &lc.channelState.RemoteChanCfg,
+		leaseExpiry, &lc.channelState.LocalChanCfg,
-		newCommitView,
+		&lc.channelState.RemoteChanCfg, newCommitView,
 	)
 	if err != nil {
 		return sig, htlcSigs, nil, err
@@ -4067,7 +4081,7 @@ func (lc *LightningChannel) computeView(view *htlcView, remoteChain bool,
 // directly into the pool of workers.
 func genHtlcSigValidationJobs(localCommitmentView *commitment,
 	keyRing *CommitmentKeyRing, htlcSigs []lnwire.Sig,
-	chanType channeldb.ChannelType,
+	chanType channeldb.ChannelType, isLocalInitiator bool, leaseExpiry uint32,
 	localChanCfg, remoteChanCfg *channeldb.ChannelConfig) ([]VerifyJob, error) {
 
 	txHash := localCommitmentView.txn.TxHash()
@@ -4116,9 +4130,10 @@ func genHtlcSigValidationJobs(localCommitmentView *commitment,
 				outputAmt := htlc.Amount.ToSatoshis() - htlcFee
 
 				successTx, err := CreateHtlcSuccessTx(
-					chanType, op, outputAmt,
+					chanType, isLocalInitiator, op,
-					uint32(localChanCfg.CsvDelay),
+					outputAmt, uint32(localChanCfg.CsvDelay),
-					keyRing.RevocationKey, keyRing.ToLocalKey,
+					leaseExpiry, keyRing.RevocationKey,
+					keyRing.ToLocalKey,
 				)
 				if err != nil {
 					return nil, err
@@ -4170,8 +4185,9 @@ func genHtlcSigValidationJobs(localCommitmentView *commitment,
 				outputAmt := htlc.Amount.ToSatoshis() - htlcFee
 
 				timeoutTx, err := CreateHtlcTimeoutTx(
-					chanType, op, outputAmt, htlc.Timeout,
+					chanType, isLocalInitiator, op,
-					uint32(localChanCfg.CsvDelay),
+					outputAmt, htlc.Timeout,
+					uint32(localChanCfg.CsvDelay), leaseExpiry,
 					keyRing.RevocationKey, keyRing.ToLocalKey,
 				)
 				if err != nil {
@@ -4385,9 +4401,14 @@ func (lc *LightningChannel) ReceiveNewCommitment(commitSig lnwire.Sig,
 	// As an optimization, we'll generate a series of jobs for the worker
 	// pool to verify each of the HTLc signatures presented. Once
 	// generated, we'll submit these jobs to the worker pool.
+	var leaseExpiry uint32
+	if lc.channelState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = lc.channelState.ThawHeight
+	}
 	verifyJobs, err := genHtlcSigValidationJobs(
 		localCommitmentView, keyRing, htlcSigs,
-		lc.channelState.ChanType, &lc.channelState.LocalChanCfg,
+		lc.channelState.ChanType, lc.channelState.IsInitiator,
+		leaseExpiry, &lc.channelState.LocalChanCfg,
 		&lc.channelState.RemoteChanCfg,
 	)
 	if err != nil {
@@ -5570,18 +5591,24 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer input.Si
 
 	// First, we'll generate the commitment point and the revocation point
 	// so we can re-construct the HTLC state and also our payment key.
+	isOurCommit := false
 	keyRing := DeriveCommitmentKeys(
-		commitPoint, false, chanState.ChanType,
+		commitPoint, isOurCommit, chanState.ChanType,
 		&chanState.LocalChanCfg, &chanState.RemoteChanCfg,
 	)
 
 	// Next, we'll obtain HTLC resolutions for all the outgoing HTLC's we
 	// had on their commitment transaction.
+	var leaseExpiry uint32
+	if chanState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = chanState.ThawHeight
+	}
+	isRemoteInitiator := !chanState.IsInitiator
 	htlcResolutions, err := extractHtlcResolutions(
-		chainfee.SatPerKWeight(remoteCommit.FeePerKw), false, signer,
+		chainfee.SatPerKWeight(remoteCommit.FeePerKw), isOurCommit,
-		remoteCommit.Htlcs, keyRing, &chanState.LocalChanCfg,
+		signer, remoteCommit.Htlcs, keyRing, &chanState.LocalChanCfg,
 		&chanState.RemoteChanCfg, commitSpend.SpendingTx,
-		chanState.ChanType,
+		chanState.ChanType, isRemoteInitiator, leaseExpiry,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("unable to create htlc "+
@@ -5594,7 +5621,8 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer input.Si
 	// locate the output index of our non-delayed output on the commitment
 	// transaction.
 	selfScript, maturityDelay, err := CommitScriptToRemote(
-		chanState.ChanType, keyRing.ToRemoteKey,
+		chanState.ChanType, isRemoteInitiator, keyRing.ToRemoteKey,
+		leaseExpiry,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("unable to create self commit "+
@@ -5801,8 +5829,9 @@ type HtlcResolutions struct {
 func newOutgoingHtlcResolution(signer input.Signer,
 	localChanCfg *channeldb.ChannelConfig, commitTx *wire.MsgTx,
 	htlc *channeldb.HTLC, keyRing *CommitmentKeyRing,
-	feePerKw chainfee.SatPerKWeight, csvDelay uint32,
+	feePerKw chainfee.SatPerKWeight, csvDelay, leaseExpiry uint32,
-	localCommit bool, chanType channeldb.ChannelType) (*OutgoingHtlcResolution, error) {
+	localCommit, isCommitFromInitiator bool,
+	chanType channeldb.ChannelType) (*OutgoingHtlcResolution, error) {
 
 	op := wire.OutPoint{
 		Hash:  commitTx.TxHash(),
@@ -5854,8 +5883,9 @@ func newOutgoingHtlcResolution(signer input.Signer,
 	// With the fee calculated, re-construct the second level timeout
 	// transaction.
 	timeoutTx, err := CreateHtlcTimeoutTx(
-		chanType, op, secondLevelOutputAmt, htlc.RefundTimeout,
+		chanType, isCommitFromInitiator, op, secondLevelOutputAmt,
-		csvDelay, keyRing.RevocationKey, keyRing.ToLocalKey,
+		htlc.RefundTimeout, csvDelay, leaseExpiry, keyRing.RevocationKey,
+		keyRing.ToLocalKey,
 	)
 	if err != nil {
 		return nil, err
@@ -5901,7 +5931,8 @@ func newOutgoingHtlcResolution(signer input.Signer,
 	// transaction creates so we can generate the signDesc required to
 	// complete the claim process after a delay period.
 	htlcSweepScript, err := SecondLevelHtlcScript(
-		keyRing.RevocationKey, keyRing.ToLocalKey, csvDelay,
+		chanType, isCommitFromInitiator, keyRing.RevocationKey,
+		keyRing.ToLocalKey, csvDelay, leaseExpiry,
 	)
 	if err != nil {
 		return nil, err
@@ -5942,8 +5973,9 @@ func newOutgoingHtlcResolution(signer input.Signer,
 func newIncomingHtlcResolution(signer input.Signer,
 	localChanCfg *channeldb.ChannelConfig, commitTx *wire.MsgTx,
 	htlc *channeldb.HTLC, keyRing *CommitmentKeyRing,
-	feePerKw chainfee.SatPerKWeight, csvDelay uint32, localCommit bool,
+	feePerKw chainfee.SatPerKWeight, csvDelay, leaseExpiry uint32,
-	chanType channeldb.ChannelType) (*IncomingHtlcResolution, error) {
+	localCommit, isCommitFromInitiator bool, chanType channeldb.ChannelType) (
+	*IncomingHtlcResolution, error) {
 
 	op := wire.OutPoint{
 		Hash:  commitTx.TxHash(),
@@ -5988,8 +6020,8 @@ func newIncomingHtlcResolution(signer input.Signer,
 	htlcFee := HtlcSuccessFee(chanType, feePerKw)
 	secondLevelOutputAmt := htlc.Amt.ToSatoshis() - htlcFee
 	successTx, err := CreateHtlcSuccessTx(
-		chanType, op, secondLevelOutputAmt, csvDelay,
+		chanType, isCommitFromInitiator, op, secondLevelOutputAmt,
-		keyRing.RevocationKey, keyRing.ToLocalKey,
+		csvDelay, leaseExpiry, keyRing.RevocationKey, keyRing.ToLocalKey,
 	)
 	if err != nil {
 		return nil, err
@@ -6036,7 +6068,8 @@ func newIncomingHtlcResolution(signer input.Signer,
 	// creates so we can generate the proper signDesc to sweep it after the
 	// CSV delay has passed.
 	htlcSweepScript, err := SecondLevelHtlcScript(
-		keyRing.RevocationKey, keyRing.ToLocalKey, csvDelay,
+		chanType, isCommitFromInitiator, keyRing.RevocationKey,
+		keyRing.ToLocalKey, csvDelay, leaseExpiry,
 	)
 	if err != nil {
 		return nil, err
@@ -6096,8 +6129,8 @@ func (r *OutgoingHtlcResolution) HtlcPoint() wire.OutPoint {
 func extractHtlcResolutions(feePerKw chainfee.SatPerKWeight, ourCommit bool,
 	signer input.Signer, htlcs []channeldb.HTLC, keyRing *CommitmentKeyRing,
 	localChanCfg, remoteChanCfg *channeldb.ChannelConfig,
-	commitTx *wire.MsgTx, chanType channeldb.ChannelType) (
+	commitTx *wire.MsgTx, chanType channeldb.ChannelType,
-	*HtlcResolutions, error) {
+	isCommitFromInitiator bool, leaseExpiry uint32) (*HtlcResolutions, error) {
 
 	// TODO(roasbeef): don't need to swap csv delay?
 	dustLimit := remoteChanCfg.DustLimit
@@ -6129,8 +6162,8 @@ func extractHtlcResolutions(feePerKw chainfee.SatPerKWeight, ourCommit bool,
 			// as we can satisfy the contract.
 			ihr, err := newIncomingHtlcResolution(
 				signer, localChanCfg, commitTx, &htlc,
-				keyRing, feePerKw, uint32(csvDelay), ourCommit,
+				keyRing, feePerKw, uint32(csvDelay), leaseExpiry,
-				chanType,
+				ourCommit, isCommitFromInitiator, chanType,
 			)
 			if err != nil {
 				return nil, err
@@ -6142,7 +6175,8 @@ func extractHtlcResolutions(feePerKw chainfee.SatPerKWeight, ourCommit bool,
 
 		ohr, err := newOutgoingHtlcResolution(
 			signer, localChanCfg, commitTx, &htlc, keyRing,
-			feePerKw, uint32(csvDelay), ourCommit, chanType,
+			feePerKw, uint32(csvDelay), leaseExpiry, ourCommit,
+			isCommitFromInitiator, chanType,
 		)
 		if err != nil {
 			return nil, err
@@ -6281,8 +6315,13 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel,
 		&chanState.LocalChanCfg, &chanState.RemoteChanCfg,
 	)
 
+	var leaseExpiry uint32
+	if chanState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = chanState.ThawHeight
+	}
 	toLocalScript, err := CommitScriptToSelf(
-		keyRing.ToLocalKey, keyRing.RevocationKey, csvTimeout,
+		chanState.ChanType, chanState.IsInitiator, keyRing.ToLocalKey,
+		keyRing.RevocationKey, csvTimeout, leaseExpiry,
 	)
 	if err != nil {
 		return nil, err
@@ -6343,6 +6382,7 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel,
 		chainfee.SatPerKWeight(localCommit.FeePerKw), true, signer,
 		localCommit.Htlcs, keyRing, &chanState.LocalChanCfg,
 		&chanState.RemoteChanCfg, commitTx, chanState.ChanType,
+		chanState.IsInitiator, leaseExpiry,
 	)
 	if err != nil {
 		return nil, err

lnwallet/commitment.go

@@ -192,14 +192,31 @@ type ScriptInfo struct {
 
 // CommitScriptToSelf constructs the public key script for the output on the
 // commitment transaction paying to the "owner" of said commitment transaction.
-// If the other party learns of the preimage to the revocation hash, then they
+// The `initiator` argument should correspond to the owner of the commitment
-// can claim all the settled funds in the channel, plus the unsettled funds.
+// tranasction which we are generating the to_local script for. If the other
-func CommitScriptToSelf(selfKey, revokeKey *btcec.PublicKey, csvDelay uint32) (
+// party learns of the preimage to the revocation hash, then they can claim all
+// the settled funds in the channel, plus the unsettled funds.
+func CommitScriptToSelf(chanType channeldb.ChannelType, initiator bool,
+	selfKey, revokeKey *btcec.PublicKey, csvDelay, leaseExpiry uint32) (
 	*ScriptInfo, error) {
 
-	toLocalRedeemScript, err := input.CommitScriptToSelf(
+	var (
-		csvDelay, selfKey, revokeKey,
+		toLocalRedeemScript []byte
+		err                 error
 	)
+	switch {
+	// If we are the initiator of a leased channel, then we have an
+	// additional CLTV requirement in addition to the usual CSV requirement.
+	case initiator && chanType.HasLeaseExpiration():
+		toLocalRedeemScript, err = input.LeaseCommitScriptToSelf(
+			selfKey, revokeKey, csvDelay, leaseExpiry,
+		)
+
+	default:
+		toLocalRedeemScript, err = input.CommitScriptToSelf(
+			csvDelay, selfKey, revokeKey,
+		)
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -216,14 +233,38 @@ func CommitScriptToSelf(selfKey, revokeKey *btcec.PublicKey, csvDelay uint32) (
 }
 
 // CommitScriptToRemote derives the appropriate to_remote script based on the
-// channel's commitment type. The second return value is the CSV delay of the
+// channel's commitment type. The `initiator` argument should correspond to the
-// output script, what must be satisfied in order to spend the output.
+// owner of the commitment tranasction which we are generating the to_remote
-func CommitScriptToRemote(chanType channeldb.ChannelType,
+// script for. The second return value is the CSV delay of the output script,
-	key *btcec.PublicKey) (*ScriptInfo, uint32, error) {
+// what must be satisfied in order to spend the output.
+func CommitScriptToRemote(chanType channeldb.ChannelType, initiator bool,
+	key *btcec.PublicKey, leaseExpiry uint32) (*ScriptInfo, uint32, error) {
+
+	switch {
+	// If we are not the initiator of a leased channel, then the remote
+	// party has an additional CLTV requirement in addition to the 1 block
+	// CSV requirement.
+	case chanType.HasLeaseExpiration() && !initiator:
+		script, err := input.LeaseCommitScriptToRemoteConfirmed(
+			key, leaseExpiry,
+		)
+		if err != nil {
+			return nil, 0, err
+		}
+
+		p2wsh, err := input.WitnessScriptHash(script)
+		if err != nil {
+			return nil, 0, err
+		}
+
+		return &ScriptInfo{
+			PkScript:      p2wsh,
+			WitnessScript: script,
+		}, 1, nil
 
 	// If this channel type has anchors, we derive the delayed to_remote
 	// script.
-	if chanType.HasAnchors() {
+	case chanType.HasAnchors():
 		script, err := input.CommitScriptToRemoteConfirmed(key)
 		if err != nil {
 			return nil, 0, err
@@ -238,20 +279,22 @@ func CommitScriptToRemote(chanType channeldb.ChannelType,
 			PkScript:      p2wsh,
 			WitnessScript: script,
 		}, 1, nil
-	}
 
-	// Otherwise the to_remote will be a simple p2wkh.
+	default:
-	p2wkh, err := input.CommitScriptUnencumbered(key)
+		// Otherwise the to_remote will be a simple p2wkh.
-	if err != nil {
+		p2wkh, err := input.CommitScriptUnencumbered(key)
-		return nil, 0, err
+		if err != nil {
-	}
+			return nil, 0, err
+		}
 
-	// Since this is a regular P2WKH, the WitnessScipt and PkScript should
+		// Since this is a regular P2WKH, the WitnessScipt and PkScript
-	// both be set to the script hash.
+		// should both be set to the script hash.
-	return &ScriptInfo{
+		return &ScriptInfo{
-		WitnessScript: p2wkh,
+			WitnessScript: p2wkh,
-		PkScript:      p2wkh,
+			PkScript:      p2wkh,
-	}, 0, nil
+		}, 0, nil
+
+	}
 }
 
 // HtlcSigHashType returns the sighash type to use for HTLC success and timeout
@@ -296,13 +339,30 @@ func HtlcSecondLevelInputSequence(chanType channeldb.ChannelType) uint32 {
 // on the channel's commitment type. It is the uniform script that's used as the
 // output for the second-level HTLC transactions. The second level transaction
 // act as a sort of covenant, ensuring that a 2-of-2 multi-sig output can only
-// be spent in a particular way, and to a particular output.
+// be spent in a particular way, and to a particular output. The `initiator`
-func SecondLevelHtlcScript(revocationKey, delayKey *btcec.PublicKey,
+// argument should correspond to the owner of the commitment tranasction which
-	csvDelay uint32) (*ScriptInfo, error) {
+// we are generating the to_local script for.
+func SecondLevelHtlcScript(chanType channeldb.ChannelType, initiator bool,
+	revocationKey, delayKey *btcec.PublicKey,
+	csvDelay, leaseExpiry uint32) (*ScriptInfo, error) {
 
-	witnessScript, err := input.SecondLevelHtlcScript(
+	var (
-		revocationKey, delayKey, csvDelay,
+		witnessScript []byte
+		err           error
 	)
+	switch {
+	// If we are the initiator of a leased channel, then we have an
+	// additional CLTV requirement in addition to the usual CSV requirement.
+	case initiator && chanType.HasLeaseExpiration():
+		witnessScript, err = input.LeaseSecondLevelHtlcScript(
+			revocationKey, delayKey, csvDelay, leaseExpiry,
+		)
+
+	default:
+		witnessScript, err = input.SecondLevelHtlcScript(
+			revocationKey, delayKey, csvDelay,
+		)
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -549,19 +609,23 @@ func (cb *CommitmentBuilder) createUnsignedCommitmentTx(ourBalance,
 	// CreateCommitTx with parameters matching the perspective, to generate
 	// a new commitment transaction with all the latest unsettled/un-timed
 	// out HTLCs.
+	var leaseExpiry uint32
+	if cb.chanState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = cb.chanState.ThawHeight
+	}
 	if isOurs {
 		commitTx, err = CreateCommitTx(
 			cb.chanState.ChanType, fundingTxIn(cb.chanState), keyRing,
 			&cb.chanState.LocalChanCfg, &cb.chanState.RemoteChanCfg,
 			ourBalance.ToSatoshis(), theirBalance.ToSatoshis(),
-			numHTLCs,
+			numHTLCs, cb.chanState.IsInitiator, leaseExpiry,
 		)
 	} else {
 		commitTx, err = CreateCommitTx(
 			cb.chanState.ChanType, fundingTxIn(cb.chanState), keyRing,
 			&cb.chanState.RemoteChanCfg, &cb.chanState.LocalChanCfg,
 			theirBalance.ToSatoshis(), ourBalance.ToSatoshis(),
-			numHTLCs,
+			numHTLCs, !cb.chanState.IsInitiator, leaseExpiry,
 		)
 	}
 	if err != nil {
@@ -660,12 +724,13 @@ func (cb *CommitmentBuilder) createUnsignedCommitmentTx(ourBalance,
 // output paying to the "owner" of the commitment transaction which can be
 // spent after a relative block delay or revocation event, and a remote output
 // paying the counterparty within the channel, which can be spent immediately
-// or after a delay depending on the commitment type..
+// or after a delay depending on the commitment type. The `initiator` argument
+// should correspond to the owner of the commitment tranasction we are creating.
 func CreateCommitTx(chanType channeldb.ChannelType,
 	fundingOutput wire.TxIn, keyRing *CommitmentKeyRing,
 	localChanCfg, remoteChanCfg *channeldb.ChannelConfig,
 	amountToLocal, amountToRemote btcutil.Amount,
-	numHTLCs int64) (*wire.MsgTx, error) {
+	numHTLCs int64, initiator bool, leaseExpiry uint32) (*wire.MsgTx, error) {
 
 	// First, we create the script for the delayed "pay-to-self" output.
 	// This output has 2 main redemption clauses: either we can redeem the
@@ -673,8 +738,8 @@ func CreateCommitTx(chanType channeldb.ChannelType,
 	// the funds with the revocation key if we broadcast a revoked
 	// commitment transaction.
 	toLocalScript, err := CommitScriptToSelf(
-		keyRing.ToLocalKey, keyRing.RevocationKey,
+		chanType, initiator, keyRing.ToLocalKey, keyRing.RevocationKey,
-		uint32(localChanCfg.CsvDelay),
+		uint32(localChanCfg.CsvDelay), leaseExpiry,
 	)
 	if err != nil {
 		return nil, err
@@ -682,7 +747,7 @@ func CreateCommitTx(chanType channeldb.ChannelType,
 
 	// Next, we create the script paying to the remote.
 	toRemoteScript, _, err := CommitScriptToRemote(
-		chanType, keyRing.ToRemoteKey,
+		chanType, initiator, keyRing.ToRemoteKey, leaseExpiry,
 	)
 	if err != nil {
 		return nil, err

lnwallet/test_utils.go

@@ -119,6 +119,7 @@ func CreateTestChannels(chanType channeldb.ChannelType) (
 	channelBal := channelCapacity / 2
 	csvTimeoutAlice := uint32(5)
 	csvTimeoutBob := uint32(4)
+	isAliceInitiator := true
 
 	prevOut := &wire.OutPoint{
 		Hash:  chainhash.Hash(testHdSeed),
@@ -223,7 +224,7 @@ func CreateTestChannels(chanType channeldb.ChannelType) (
 
 	aliceCommitTx, bobCommitTx, err := CreateCommitmentTxns(
 		channelBal, channelBal, &aliceCfg, &bobCfg, aliceCommitPoint,
-		bobCommitPoint, *fundingTxIn, chanType,
+		bobCommitPoint, *fundingTxIn, chanType, isAliceInitiator, 0,
 	)
 	if err != nil {
 		return nil, nil, nil, err
@@ -318,7 +319,7 @@ func CreateTestChannels(chanType channeldb.ChannelType) (
 		FundingOutpoint:         *prevOut,
 		ShortChannelID:          shortChanID,
 		ChanType:                chanType,
-		IsInitiator:             true,
+		IsInitiator:             isAliceInitiator,
 		Capacity:                channelCapacity,
 		RemoteCurrentRevocation: bobCommitPoint,
 		RevocationProducer:      alicePreimageProducer,
@@ -336,7 +337,7 @@ func CreateTestChannels(chanType channeldb.ChannelType) (
 		FundingOutpoint:         *prevOut,
 		ShortChannelID:          shortChanID,
 		ChanType:                chanType,
-		IsInitiator:             false,
+		IsInitiator:             !isAliceInitiator,
 		Capacity:                channelCapacity,
 		RemoteCurrentRevocation: aliceCommitPoint,
 		RevocationProducer:      bobPreimageProducer,

lnwallet/transactions.go

@@ -44,9 +44,10 @@ var (
 // In order to spend the HTLC output, the witness for the passed transaction
 // should be:
 //   * <0> <sender sig> <recvr sig> <preimage>
-func CreateHtlcSuccessTx(chanType channeldb.ChannelType,
+func CreateHtlcSuccessTx(chanType channeldb.ChannelType, initiator bool,
-	htlcOutput wire.OutPoint, htlcAmt btcutil.Amount, csvDelay uint32,
+	htlcOutput wire.OutPoint, htlcAmt btcutil.Amount, csvDelay,
-	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
+	leaseExpiry 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).
@@ -65,7 +66,8 @@ func CreateHtlcSuccessTx(chanType channeldb.ChannelType,
 	// level HTLC which forces a covenant w.r.t what can be done with all
 	// HTLC outputs.
 	script, err := SecondLevelHtlcScript(
-		revocationKey, delayKey, csvDelay,
+		chanType, initiator, revocationKey, delayKey, csvDelay,
+		leaseExpiry,
 	)
 	if err != nil {
 		return nil, err
@@ -97,9 +99,9 @@ func CreateHtlcSuccessTx(chanType channeldb.ChannelType,
 // 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(chanType channeldb.ChannelType,
+func CreateHtlcTimeoutTx(chanType channeldb.ChannelType, initiator bool,
 	htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
-	cltvExpiry, csvDelay uint32,
+	cltvExpiry, csvDelay, leaseExpiry uint32,
 	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
 
 	// Create a version two transaction (as the success version of this
@@ -123,7 +125,8 @@ func CreateHtlcTimeoutTx(chanType channeldb.ChannelType,
 	// level HTLC which forces a covenant w.r.t what can be done with all
 	// HTLC outputs.
 	script, err := SecondLevelHtlcScript(
-		revocationKey, delayKey, csvDelay,
+		chanType, initiator, revocationKey, delayKey, csvDelay,
+		leaseExpiry,
 	)
 	if err != nil {
 		return nil, err

lnwallet/transactions_test.go

@@ -573,7 +573,7 @@ func testSpendValidation(t *testing.T, tweakless bool) {
 	}
 	commitmentTx, err := CreateCommitTx(
 		channelType, *fakeFundingTxIn, keyRing, aliceChanCfg,
-		bobChanCfg, channelBalance, channelBalance, 0,
+		bobChanCfg, channelBalance, channelBalance, 0, true, 0,
 	)
 	if err != nil {
 		t.Fatalf("unable to create commitment transaction: %v", nil)
@@ -889,7 +889,7 @@ func createTestChannelsForVectors(tc *testContext, chanType channeldb.ChannelTyp
 	remoteCommitTx, localCommitTx, err := CreateCommitmentTxns(
 		remoteBalance, localBalance-commitFee,
 		&remoteCfg, &localCfg, remoteCommitPoint,
-		localCommitPoint, *fundingTxIn, chanType,
+		localCommitPoint, *fundingTxIn, chanType, true, 0,
 	)
 	require.NoError(t, err)
 

lnwallet/wallet.go

@@ -1246,8 +1246,8 @@ func (l *LightningWallet) handleFundingCancelRequest(req *fundingReserveCancelMs
 func CreateCommitmentTxns(localBalance, remoteBalance btcutil.Amount,
 	ourChanCfg, theirChanCfg *channeldb.ChannelConfig,
 	localCommitPoint, remoteCommitPoint *btcec.PublicKey,
-	fundingTxIn wire.TxIn, chanType channeldb.ChannelType) (
+	fundingTxIn wire.TxIn, chanType channeldb.ChannelType, initiator bool,
-	*wire.MsgTx, *wire.MsgTx, error) {
+	leaseExpiry uint32) (*wire.MsgTx, *wire.MsgTx, error) {
 
 	localCommitmentKeys := DeriveCommitmentKeys(
 		localCommitPoint, true, chanType, ourChanCfg, theirChanCfg,
@@ -1258,7 +1258,8 @@ func CreateCommitmentTxns(localBalance, remoteBalance btcutil.Amount,
 
 	ourCommitTx, err := CreateCommitTx(
 		chanType, fundingTxIn, localCommitmentKeys, ourChanCfg,
-		theirChanCfg, localBalance, remoteBalance, 0,
+		theirChanCfg, localBalance, remoteBalance, 0, initiator,
+		leaseExpiry,
 	)
 	if err != nil {
 		return nil, nil, err
@@ -1271,7 +1272,8 @@ func CreateCommitmentTxns(localBalance, remoteBalance btcutil.Amount,
 
 	theirCommitTx, err := CreateCommitTx(
 		chanType, fundingTxIn, remoteCommitmentKeys, theirChanCfg,
-		ourChanCfg, remoteBalance, localBalance, 0,
+		ourChanCfg, remoteBalance, localBalance, 0, !initiator,
+		leaseExpiry,
 	)
 	if err != nil {
 		return nil, nil, err
@@ -1522,12 +1524,17 @@ func (l *LightningWallet) handleChanPointReady(req *continueContributionMsg) {
 	// With the funding tx complete, create both commitment transactions.
 	localBalance := pendingReservation.partialState.LocalCommitment.LocalBalance.ToSatoshis()
 	remoteBalance := pendingReservation.partialState.LocalCommitment.RemoteBalance.ToSatoshis()
+	var leaseExpiry uint32
+	if pendingReservation.partialState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = pendingReservation.partialState.ThawHeight
+	}
 	ourCommitTx, theirCommitTx, err := CreateCommitmentTxns(
 		localBalance, remoteBalance, ourContribution.ChannelConfig,
 		theirContribution.ChannelConfig,
 		ourContribution.FirstCommitmentPoint,
 		theirContribution.FirstCommitmentPoint, fundingTxIn,
 		pendingReservation.partialState.ChanType,
+		pendingReservation.partialState.IsInitiator, leaseExpiry,
 	)
 	if err != nil {
 		req.err <- err
@@ -1894,6 +1901,10 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 	// remote node's commitment transactions.
 	localBalance := pendingReservation.partialState.LocalCommitment.LocalBalance.ToSatoshis()
 	remoteBalance := pendingReservation.partialState.LocalCommitment.RemoteBalance.ToSatoshis()
+	var leaseExpiry uint32
+	if pendingReservation.partialState.ChanType.HasLeaseExpiration() {
+		leaseExpiry = pendingReservation.partialState.ThawHeight
+	}
 	ourCommitTx, theirCommitTx, err := CreateCommitmentTxns(
 		localBalance, remoteBalance,
 		pendingReservation.ourContribution.ChannelConfig,
@@ -1901,6 +1912,7 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 		pendingReservation.ourContribution.FirstCommitmentPoint,
 		pendingReservation.theirContribution.FirstCommitmentPoint,
 		*fundingTxIn, pendingReservation.partialState.ChanType,
+		pendingReservation.partialState.IsInitiator, leaseExpiry,
 	)
 	if err != nil {
 		req.err <- err

peer/test_utils.go

@@ -79,6 +79,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 	bobDustLimit := btcutil.Amount(1300)
 	csvTimeoutAlice := uint32(5)
 	csvTimeoutBob := uint32(4)
+	isAliceInitiator := true
 
 	prevOut := &wire.OutPoint{
 		Hash:  channels.TestHdSeed,
@@ -162,6 +163,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 	aliceCommitTx, bobCommitTx, err := lnwallet.CreateCommitmentTxns(
 		channelBal, channelBal, &aliceCfg, &bobCfg, aliceCommitPoint,
 		bobCommitPoint, *fundingTxIn, channeldb.SingleFunderTweaklessBit,
+		isAliceInitiator, 0,
 	)
 	if err != nil {
 		return nil, nil, nil, err
@@ -229,7 +231,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 		FundingOutpoint:         *prevOut,
 		ShortChannelID:          shortChanID,
 		ChanType:                channeldb.SingleFunderTweaklessBit,
-		IsInitiator:             true,
+		IsInitiator:             isAliceInitiator,
 		Capacity:                channelCapacity,
 		RemoteCurrentRevocation: bobCommitPoint,
 		RevocationProducer:      alicePreimageProducer,
@@ -246,7 +248,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 		IdentityPub:             bobKeyPub,
 		FundingOutpoint:         *prevOut,
 		ChanType:                channeldb.SingleFunderTweaklessBit,
-		IsInitiator:             false,
+		IsInitiator:             !isAliceInitiator,
 		Capacity:                channelCapacity,
 		RemoteCurrentRevocation: aliceCommitPoint,
 		RevocationProducer:      bobPreimageProducer,