rpc+funding: add taproot overlay as RPC chan type

funding/manager_test.go

@@ -4642,8 +4642,8 @@ func testZeroConf(t *testing.T, chanType *lnwire.ChannelType) {
 // opening behavior with a specified fundmax flag. To give a hypothetical
 // example, if ANCHOR types had been introduced after the fundmax flag had been
 // activated, the developer would have had to code for the anchor reserve in the
-// funding manager in the context of public and private channels. Otherwise
-// inconsistent bahvior would have resulted when specifying fundmax for
+// funding manager in the context of public and private channels. Otherwise,
+// inconsistent behavior would have resulted when specifying fundmax for
 // different types of channel openings.
 // To ensure consistency this test compares a map of locally defined channel
 // commitment types to the list of channel types that are defined in the proto
@@ -4659,6 +4659,7 @@ func TestCommitmentTypeFundmaxSanityCheck(t *testing.T) {
 		"ANCHORS":                 3,
 		"SCRIPT_ENFORCED_LEASE":   4,
 		"SIMPLE_TAPROOT":          5,
+		"SIMPLE_TAPROOT_OVERLAY":  6,
 	}
 
 	for commitmentType := range lnrpc.CommitmentType_value {

rpcserver.go

@@ -2293,6 +2293,29 @@ func (r *rpcServer) parseOpenChannelReq(in *lnrpc.OpenChannelRequest,
 
 		*channelType = lnwire.ChannelType(*fv)
 
+	case lnrpc.CommitmentType_SIMPLE_TAPROOT_OVERLAY:
+		// If the taproot overlay channel type is being set, then the
+		// channel MUST be private.
+		if !in.Private {
+			return nil, fmt.Errorf("taproot overlay channels " +
+				"must be private")
+		}
+
+		channelType = new(lnwire.ChannelType)
+		fv := lnwire.NewRawFeatureVector(
+			lnwire.SimpleTaprootOverlayChansRequired,
+		)
+
+		if in.ZeroConf {
+			fv.Set(lnwire.ZeroConfRequired)
+		}
+
+		if in.ScidAlias {
+			fv.Set(lnwire.ScidAliasRequired)
+		}
+
+		*channelType = lnwire.ChannelType(*fv)
+
 	default:
 		return nil, fmt.Errorf("unhandled request channel type %v",
 			in.CommitmentType)
@@ -4527,6 +4550,9 @@ func rpcCommitmentType(chanType channeldb.ChannelType) lnrpc.CommitmentType {
 	case chanType.IsTaproot():
 		return lnrpc.CommitmentType_SIMPLE_TAPROOT
 
+	case chanType.HasTapscriptRoot():
+		return lnrpc.CommitmentType_SIMPLE_TAPROOT_OVERLAY
+
 	case chanType.HasLeaseExpiration():
 		return lnrpc.CommitmentType_SCRIPT_ENFORCED_LEASE