Add a new WarningMessage message to send and receive warnings

Author: TheBlueMatt

fuzz/src/msg_targets/gen_target.sh

@@ -43,4 +43,5 @@ GEN_TEST QueryShortChannelIds test_msg ""
 GEN_TEST ReplyChannelRange test_msg ""
 
 GEN_TEST ErrorMessage test_msg_hole ", 32, 2"
+GEN_TEST WarningMessage test_msg_hole ", 32, 2"
 GEN_TEST ChannelUpdate test_msg_hole ", 108, 1"

fuzz/src/msg_targets/mod.rs

@@ -28,4 +28,5 @@ pub mod msg_node_announcement;
 pub mod msg_query_short_channel_ids;
 pub mod msg_reply_channel_range;
 pub mod msg_error_message;
+pub mod msg_warning_message;
 pub mod msg_channel_update;

fuzz/src/msg_targets/msg_warning_message.rs

@@ -0,0 +1,27 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+// This file is auto-generated by gen_target.sh based on msg_target_template.txt
+// To modify it, modify msg_target_template.txt and run gen_target.sh instead.
+
+use lightning::ln::msgs;
+
+use msg_targets::utils::VecWriter;
+use utils::test_logger;
+
+#[inline]
+pub fn msg_warning_message_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
+	test_msg_hole!(msgs::WarningMessage, data, 32, 2);
+}
+
+#[no_mangle]
+pub extern "C" fn msg_warning_message_run(data: *const u8, datalen: usize) {
+	let data = unsafe { std::slice::from_raw_parts(data, datalen) };
+	test_msg_hole!(msgs::WarningMessage, data, 32, 2);
+}

lightning/src/ln/msgs.rs

@@ -80,12 +80,29 @@ pub struct Init {
 /// An error message to be sent or received from a peer
 #[derive(Clone, Debug, PartialEq)]
 pub struct ErrorMessage {
-	/// The channel ID involved in the error
+	/// The channel ID involved in the error.
+	///
+	/// All-0s indicates a general error unrelated to a specific channel, after which all channels
+	/// with the sending peer should be closed.
 	pub channel_id: [u8; 32],
 	/// A possibly human-readable error description.
-	/// The string should be sanitized before it is used (e.g. emitted to logs
-	/// or printed to stdout).  Otherwise, a well crafted error message may trigger a security
-	/// vulnerability in the terminal emulator or the logging subsystem.
+	/// The string should be sanitized before it is used (e.g. emitted to logs or printed to
+	/// stdout). Otherwise, a well crafted error message may trigger a security vulnerability in
+	/// the terminal emulator or the logging subsystem.
+	pub data: String,
+}
+
+/// A warning message to be sent or received from a peer
+#[derive(Clone, Debug, PartialEq)]
+pub struct WarningMessage {
+	/// The channel ID involved in the warning.
+	///
+	/// All-0s indicates a warning unrelated to a specific channel.
+	pub channel_id: [u8; 32],
+	/// A possibly human-readable warning description.
+	/// The string should be sanitized before it is used (e.g. emitted to logs or printed to
+	/// stdout). Otherwise, a well crafted error message may trigger a security vulnerability in
+	/// the terminal emulator or the logging subsystem.
 	pub data: String,
 }
 
@@ -1515,6 +1532,32 @@ impl Readable for ErrorMessage {
 	}
 }
 
+impl Writeable for WarningMessage {
+	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+		self.channel_id.write(w)?;
+		(self.data.len() as u16).write(w)?;
+		w.write_all(self.data.as_bytes())?;
+		Ok(())
+	}
+}
+
+impl Readable for WarningMessage {
+	fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+		Ok(Self {
+			channel_id: Readable::read(r)?,
+			data: {
+				let mut sz: usize = <u16 as Readable>::read(r)? as usize;
+				let data = read_to_end(r)?;
+				sz = cmp::min(data.len(), sz);
+				match String::from_utf8(data[..sz as usize].to_vec()) {
+					Ok(s) => s,
+					Err(_) => return Err(DecodeError::InvalidValue),
+				}
+			}
+		})
+	}
+}
+
 impl Writeable for UnsignedNodeAnnouncement {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 		self.features.write(w)?;
@@ -2405,6 +2448,17 @@ mod tests {
 		assert_eq!(encoded_value, target_value);
 	}
 
+	#[test]
+	fn encoding_warning() {
+		let error = msgs::WarningMessage {
+			channel_id: [2; 32],
+			data: String::from("rust-lightning"),
+		};
+		let encoded_value = error.encode();
+		let target_value = hex::decode("0202020202020202020202020202020202020202020202020202020202020202000e727573742d6c696768746e696e67").unwrap();
+		assert_eq!(encoded_value, target_value);
+	}
+
 	#[test]
 	fn encoding_ping() {
 		let ping = msgs::Ping {