lnwallet: use custom LockTime for rbf coop close

Author: Roasbeef

lnwallet/chancloser/rbf_coop_test.go

@@ -547,8 +547,8 @@ func (r *rbfCloserTestHarness) expectHalfSignerIteration(
 		}
 
 	case *SendOfferEvent:
-		expectedStates = []RbfState{&ClosingNegotiation{}}
 
+		expectedStates = []RbfState{&ClosingNegotiation{}}
 	case *ChannelFlushed:
 		// If we're sending a flush event here, then this means that we
 		// also have enough balance to cover the fee so we'll have
@@ -1534,7 +1534,7 @@ func TestRbfCloseClosingNegotiationRemote(t *testing.T) {
 		feeOffer := &OfferReceivedEvent{
 			SigMsg: lnwire.ClosingComplete{
 				FeeSatoshis: absoluteFee,
-				LockTime:    10,
+				LockTime:    1,
 				ClosingSigs: lnwire.ClosingSigs{
 					CloserAndClosee: newSigTlv[tlv.TlvType3]( //nolint:ll
 						remoteWireSig,

lnwallet/chancloser/rbf_coop_transitions.go

@@ -902,6 +902,7 @@ func (l *RemoteCloseStart) ProcessEvent(event ProtocolEvent, env *Environment,
 
 		chanOpts := []lnwallet.ChanCloseOpt{
 			lnwallet.WithCustomSequence(mempool.MaxRBFSequence),
+			lnwallet.WithCustomLockTime(msg.SigMsg.LockTime),
 		}
 
 		chancloserLog.Infof("responding to close w/ local_addr=%x, "+

lnwallet/channel.go

@@ -8201,6 +8201,8 @@ type chanCloseOpt struct {
 	customSort CloseSortFunc
 
 	customSequence fn.Option[uint32]
+
+	customLockTime fn.Option[uint32]
 }
 
 // ChanCloseOpt is a closure type that cen be used to modify the set of default
@@ -8234,7 +8236,7 @@ func WithExtraCloseOutputs(extraOutputs []CloseOutput) ChanCloseOpt {
 func WithCustomCoopSort(sorter CloseSortFunc) ChanCloseOpt {
 	return func(opts *chanCloseOpt) {
 		opts.customSort = sorter
-    }
+	}
 }
 
 // WithCustomSequence can be used to specify a custom sequence number for the
@@ -8245,6 +8247,14 @@ func WithCustomSequence(sequence uint32) ChanCloseOpt {
 	}
 }
 
+// WithCustomLockTime can be used to specify a custom lock time for the coop
+// close transaction.
+func WithCustomLockTime(lockTime uint32) ChanCloseOpt {
+	return func(opts *chanCloseOpt) {
+		opts.customLockTime = fn.Some(lockTime)
+	}
+}
+
 // CreateCloseProposal is used by both parties in a cooperative channel close
 // workflow to generate proposed close transactions and signatures. This method
 // should only be executed once all pending HTLCs (if any) on the channel have
@@ -8310,6 +8320,12 @@ func (lc *LightningChannel) CreateCloseProposal(proposedFee btcutil.Amount,
 		))
 	})
 
+	opts.customLockTime.WhenSome(func(lockTime uint32) {
+		closeTxOpts = append(closeTxOpts, WithCustomTxLockTime(
+			lockTime,
+		))
+	})
+
 	closeTx, err := CreateCooperativeCloseTx(
 		fundingTxIn(lc.channelState), lc.channelState.LocalChanCfg.DustLimit,
 		lc.channelState.RemoteChanCfg.DustLimit, ourBalance, theirBalance,
@@ -8417,6 +8433,12 @@ func (lc *LightningChannel) CompleteCooperativeClose(
 		))
 	})
 
+	opts.customLockTime.WhenSome(func(lockTime uint32) {
+		closeTxOpts = append(closeTxOpts, WithCustomTxLockTime(
+			lockTime,
+		))
+	})
+
 	// Create the transaction used to return the current settled balance
 	// on this active channel back to both parties. In this current model,
 	// the initiator pays full fees for the cooperative close transaction.
@@ -9138,6 +9160,8 @@ type closeTxOpts struct {
 	// close transaction. This gives slightly more control compared to the
 	// enableRBF option.
 	customSequence fn.Option[uint32]
+
+	customLockTime fn.Option[uint32]
 }
 
 // defaultCloseTxOpts returns a closeTxOpts struct with default values.
@@ -9171,7 +9195,7 @@ func WithExtraTxCloseOutputs(extraOutputs []CloseOutput) CloseTxOpt {
 func WithCustomTxSort(sorter CloseSortFunc) CloseTxOpt {
 	return func(opts *closeTxOpts) {
 		opts.customSort = sorter
-    }
+	}
 }
 
 // WithCustomTxInSequence allows a caller to set a custom sequence on the sole
@@ -9182,6 +9206,12 @@ func WithCustomTxInSequence(sequence uint32) CloseTxOpt {
 	}
 }
 
+func WithCustomTxLockTime(lockTime uint32) CloseTxOpt {
+	return func(o *closeTxOpts) {
+		o.customLockTime = fn.Some(lockTime)
+	}
+}
+
 // CreateCooperativeCloseTx creates a transaction which if signed by both
 // parties, then broadcast cooperatively closes an active channel. The creation
 // of the closure transaction is modified by a boolean indicating if the party
@@ -9216,6 +9246,10 @@ func CreateCooperativeCloseTx(fundingTxIn wire.TxIn,
 	closeTx := wire.NewMsgTx(2)
 	closeTx.AddTxIn(&fundingTxIn)
 
+	opts.customLockTime.WhenSome(func(lockTime uint32) {
+		closeTx.LockTime = lockTime
+	})
+
 	// TODO(roasbeef): needs support for dropping inputs
 
 	// Create both cooperative closure outputs, properly respecting the