Add support for receiving sendaddrv2 message from a peer

wire/message.go

@@ -57,6 +57,7 @@ const (
 	CmdCFilter      = "cfilter"
 	CmdCFHeaders    = "cfheaders"
 	CmdCFCheckpt    = "cfcheckpt"
+	CmdSendAddrV2   = "sendaddrv2"
 )
 
 // MessageEncoding represents the wire message encoding format to be used.
@@ -99,6 +100,9 @@ func makeEmptyMessage(command string) (Message, error) {
 	case CmdVerAck:
 		msg = &MsgVerAck{}
 
+	case CmdSendAddrV2:
+		msg = &MsgSendAddrV2{}
+
 	case CmdGetAddr:
 		msg = &MsgGetAddr{}
 

wire/msgsendaddrv2.go

@@ -0,0 +1,42 @@
+package wire
+
+import (
+	"io"
+)
+
+// MsgSendAddrV2 defines a bitcoin sendaddrv2 message which is used for a peer
+// to signal support for receiving ADDRV2 messages (BIP155). It implements the
+// Message interface.
+//
+// This message has no payload.
+type MsgSendAddrV2 struct{}
+
+// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
+// This is part of the Message interface implementation.
+func (msg *MsgSendAddrV2) BtcDecode(r io.Reader, pver uint32, enc MessageEncoding) error {
+	return nil
+}
+
+// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
+// This is part of the Message interface implementation.
+func (msg *MsgSendAddrV2) BtcEncode(w io.Writer, pver uint32, enc MessageEncoding) error {
+	return nil
+}
+
+// Command returns the protocol command string for the message.  This is part
+// of the Message interface implementation.
+func (msg *MsgSendAddrV2) Command() string {
+	return CmdSendAddrV2
+}
+
+// MaxPayloadLength returns the maximum length the payload can be for the
+// receiver.  This is part of the Message interface implementation.
+func (msg *MsgSendAddrV2) MaxPayloadLength(pver uint32) uint32 {
+	return 0
+}
+
+// NewMsgSendAddrV2 returns a new bitcoin sendaddrv2 message that conforms to the
+// Message interface.
+func NewMsgSendAddrV2() *MsgSendAddrV2 {
+	return &MsgSendAddrV2{}
+}