Captute "type" byte for unknow message type (#3146)

Found it useful for debugging

p2p/src/conn.rs

@@ -293,7 +293,11 @@ where
 							try_break!(conn_handle.send(resp_msg));
 						}
 					}
-					Some(MsgHeaderWrapper::Unknown(msg_len)) => {
+					Some(MsgHeaderWrapper::Unknown(msg_len, type_byte)) => {
+						debug!(
+							"Received unknown message header, type {:?}, len {}.",
+							type_byte, msg_len
+						);
 						// Increase received bytes counter
 						reader_tracker.inc_received(MsgHeader::LEN as u64 + msg_len);
 

p2p/src/msg.rs

@@ -205,7 +205,7 @@ pub fn read_message<T: Readable>(
 				Err(Error::BadMessage)
 			}
 		}
-		MsgHeaderWrapper::Unknown(msg_len) => {
+		MsgHeaderWrapper::Unknown(msg_len, _) => {
 			read_discard(msg_len, stream)?;
 			Err(Error::BadMessage)
 		}
@@ -248,7 +248,7 @@ pub enum MsgHeaderWrapper {
 	/// A "known" msg type with deserialized msg header.
 	Known(MsgHeader),
 	/// An unknown msg type with corresponding msg size in bytes.
-	Unknown(u64),
+	Unknown(u64, u8),
 }
 
 /// Header of any protocol message, used to identify incoming messages.
@@ -331,7 +331,7 @@ impl Readable for MsgHeaderWrapper {
 					return Err(ser::Error::TooLargeReadErr);
 				}
 
-				Ok(MsgHeaderWrapper::Unknown(msg_len))
+				Ok(MsgHeaderWrapper::Unknown(msg_len, t))
 			}
 		}
 	}