multi: switch to lock time from sequence for coop close v2

lnwallet/chancloser/rbf_coop_test.go

@@ -1430,31 +1430,6 @@ func TestRbfCloseClosingNegotiationRemote(t *testing.T) {
 		closeHarness.assertNoStateTransitions()
 	})
 
-	// If the remote party sends us a signature with a final sequence, then
-	// we'll error out as it can't be RBF'd
-	t.Run("recv_offer_final_sequence", func(t *testing.T) {
-		closeHarness := newCloser(t, &harnessCfg{
-			initialState: fn.Some[ProtocolState](startingState),
-		})
-		defer closeHarness.stopAndAssert()
-
-		// We should fail as they sent a non final sequence.
-		closeHarness.expectFailure(ErrNonFinalSequence)
-
-		// We'll send an offer with something beyond the max RBF value,
-		// this should fail.
-		feeOffer := &OfferReceivedEvent{
-			SigMsg: lnwire.ClosingComplete{
-				FeeSatoshis: absoluteFee,
-				Sequence:    mempool.MaxRBFSequence + 1,
-			},
-		}
-		closeHarness.chanCloser.SendEvent(feeOffer)
-
-		// We shouldn't have transitioned to a new state.
-		closeHarness.assertNoStateTransitions()
-	})
-
 	// If our balance, is dust, then the remote party should send a
 	// signature that doesn't include our output.
 	t.Run("recv_offer_err_closer_no_closee", func(t *testing.T) {
@@ -1559,7 +1534,7 @@ func TestRbfCloseClosingNegotiationRemote(t *testing.T) {
 		feeOffer := &OfferReceivedEvent{
 			SigMsg: lnwire.ClosingComplete{
 				FeeSatoshis: absoluteFee,
-				Sequence:    sequence,
+				LockTime:    10,
 				ClosingSigs: lnwire.ClosingSigs{
 					CloserAndClosee: newSigTlv[tlv.TlvType3]( //nolint:ll
 						remoteWireSig,

lnwallet/chancloser/rbf_coop_transitions.go

@@ -716,7 +716,9 @@ func (l *LocalCloseStart) ProcessEvent(event ProtocolEvent, env *Environment,
 			Msgs: []lnwire.Message{&lnwire.ClosingComplete{
 				ChannelID:   env.ChanID,
 				FeeSatoshis: absoluteFee,
-				Sequence:    mempool.MaxRBFSequence,
+				// TODO(roasbeef): thread thru proper height
+				// value
+				LockTime:    mempool.MaxRBFSequence,
 				ClosingSigs: closingSigs,
 			}},
 		}}
@@ -862,18 +864,11 @@ func (l *RemoteCloseStart) ProcessEvent(event ProtocolEvent, env *Environment,
 		// To start, we'll perform some basic validation of the sig
 		// message they've sent. We'll validate that the remote party
 		// actually has enough fees to pay the closing fees.
-		switch {
-		case !l.RemoteCanPayFees(msg.SigMsg.FeeSatoshis):
+		if !l.RemoteCanPayFees(msg.SigMsg.FeeSatoshis) {
 			return nil, fmt.Errorf("%w: %v vs %v",
 				ErrRemoteCannotPay,
 				msg.SigMsg.FeeSatoshis,
 				l.RemoteBalance.ToSatoshis())
-
-		// The sequence they send can't be the max sequence, as that would
-		// prevent RBF.
-		case msg.SigMsg.Sequence > mempool.MaxRBFSequence:
-			return nil, fmt.Errorf("%w: %v", ErrNonFinalSequence,
-				msg.SigMsg.Sequence)
 		}
 
 		// With the basic sanity checks out of the way, we'll now
@@ -908,7 +903,7 @@ func (l *RemoteCloseStart) ProcessEvent(event ProtocolEvent, env *Environment,
 		}
 
 		chanOpts := []lnwallet.ChanCloseOpt{
-			lnwallet.WithCustomSequence(msg.SigMsg.Sequence),
+			lnwallet.WithCustomSequence(mempool.MaxRBFSequence),
 		}
 
 		chancloserLog.Infof("responding to close w/ local_addr=%x, "+