lnwire: add musig2 taproot execution messages for dynamic commitments

lnwire/kickoff_sig.go

@@ -0,0 +1,56 @@
+package lnwire
+
+import (
+	"bytes"
+	"io"
+)
+
+// KickoffSig is the message used to transmit the signature for a kickoff
+// transaction during the execution phase of a dynamic commitment negotiation
+// that requires a reanchoring step.
+type KickoffSig struct {
+	// ChanID identifies the channel id for which this signature is
+	// intended.
+	ChanID ChannelID
+
+	// Signature contains the ECDSA signature that signs the kickoff
+	// transaction.
+	Signature Sig
+
+	// ExtraData is the set of data that was appended to this message to
+	// fill out the full maximum transport message size. These fields can
+	// be used to specify optional data such as custom TLV fields.
+	ExtraData ExtraOpaqueData
+}
+
+// A compile time check to ensure that KickoffSig implements the lnwire.Message
+// interface.
+var _ Message = (*KickoffSig)(nil)
+
+// Encode serializes the target KickoffSig into the passed bytes.Buffer
+// observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (ks *KickoffSig) Encode(w *bytes.Buffer, _ uint32) error {
+	if err := WriteChannelID(w, ks.ChanID); err != nil {
+		return err
+	}
+	if err := WriteSig(w, ks.Signature); err != nil {
+		return err
+	}
+
+	return WriteBytes(w, ks.ExtraData)
+}
+
+// Decode deserializes a serialized KickoffSig message stored in the passed
+// io.Reader observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (ks *KickoffSig) Decode(r io.Reader, _ uint32) error {
+	return ReadElements(r, &ks.ChanID, &ks.Signature, &ks.ExtraData)
+}
+
+// MsgType returns the integer uniquely identifying KickoffSig on the wire.
+//
+// This is part of the lnwire.Message interface.
+func (ks *KickoffSig) MsgType() MessageType { return MsgKickoffSig }