1 //! Wire encoding/decoding for Lightning messages according to [BOLT #1].
3 //! Messages known by this module can be read from the wire using [`read`].
4 //! The [`Message`] enum returned by [`read`] wraps the decoded message or the message type (if
5 //! unknown) to use with pattern matching.
7 //! Messages implementing the [`Encode`] trait define a message type and can be sent over the wire
10 //! [BOLT #1]: https://github.com/lightningnetwork/lightning-rfc/blob/master/01-messaging.md
11 //! [`read`]: fn.read.html
12 //! [`write`]: fn.write.html
13 //! [`Encode`]: trait.Encode.html
14 //! [`Message`]: enum.Message.html
17 use util::ser::{Readable, Writeable, Writer};
19 /// Maximum Lightning message data length according to
20 /// [BOLT-8](https://github.com/lightningnetwork/lightning-rfc/blob/v1.0/08-transport.md#lightning-message-specification)
21 /// and [BOLT-1](https://github.com/lightningnetwork/lightning-rfc/blob/master/01-messaging.md#lightning-message-format):
22 pub const LN_MAX_MSG_LEN: usize = std::u16::MAX as usize; // Must be equal to 65535
24 /// A Lightning message returned by [`read`] when decoding bytes received over the wire. Each
25 /// variant contains a message from [`ln::msgs`] or otherwise the message type if unknown.
27 /// [`read`]: fn.read.html
28 /// [`ln::msgs`]: ../msgs/index.html
29 #[allow(missing_docs)]
32 Error(msgs::ErrorMessage),
35 OpenChannel(msgs::OpenChannel),
36 AcceptChannel(msgs::AcceptChannel),
37 FundingCreated(msgs::FundingCreated),
38 FundingSigned(msgs::FundingSigned),
39 FundingLocked(msgs::FundingLocked),
40 Shutdown(msgs::Shutdown),
41 ClosingSigned(msgs::ClosingSigned),
42 UpdateAddHTLC(msgs::UpdateAddHTLC),
43 UpdateFulfillHTLC(msgs::UpdateFulfillHTLC),
44 UpdateFailHTLC(msgs::UpdateFailHTLC),
45 UpdateFailMalformedHTLC(msgs::UpdateFailMalformedHTLC),
46 CommitmentSigned(msgs::CommitmentSigned),
47 RevokeAndACK(msgs::RevokeAndACK),
48 UpdateFee(msgs::UpdateFee),
49 ChannelReestablish(msgs::ChannelReestablish),
50 AnnouncementSignatures(msgs::AnnouncementSignatures),
51 ChannelAnnouncement(msgs::ChannelAnnouncement),
52 NodeAnnouncement(msgs::NodeAnnouncement),
53 ChannelUpdate(msgs::ChannelUpdate),
54 /// A message that could not be decoded because its type is unknown.
58 /// A number identifying a message to determine how it is encoded on the wire.
59 #[derive(Clone, Copy)]
60 pub struct MessageType(u16);
63 /// Returns the type that was used to decode the message payload.
64 pub fn type_id(&self) -> MessageType {
66 &Message::Init(ref msg) => msg.type_id(),
67 &Message::Error(ref msg) => msg.type_id(),
68 &Message::Ping(ref msg) => msg.type_id(),
69 &Message::Pong(ref msg) => msg.type_id(),
70 &Message::OpenChannel(ref msg) => msg.type_id(),
71 &Message::AcceptChannel(ref msg) => msg.type_id(),
72 &Message::FundingCreated(ref msg) => msg.type_id(),
73 &Message::FundingSigned(ref msg) => msg.type_id(),
74 &Message::FundingLocked(ref msg) => msg.type_id(),
75 &Message::Shutdown(ref msg) => msg.type_id(),
76 &Message::ClosingSigned(ref msg) => msg.type_id(),
77 &Message::UpdateAddHTLC(ref msg) => msg.type_id(),
78 &Message::UpdateFulfillHTLC(ref msg) => msg.type_id(),
79 &Message::UpdateFailHTLC(ref msg) => msg.type_id(),
80 &Message::UpdateFailMalformedHTLC(ref msg) => msg.type_id(),
81 &Message::CommitmentSigned(ref msg) => msg.type_id(),
82 &Message::RevokeAndACK(ref msg) => msg.type_id(),
83 &Message::UpdateFee(ref msg) => msg.type_id(),
84 &Message::ChannelReestablish(ref msg) => msg.type_id(),
85 &Message::AnnouncementSignatures(ref msg) => msg.type_id(),
86 &Message::ChannelAnnouncement(ref msg) => msg.type_id(),
87 &Message::NodeAnnouncement(ref msg) => msg.type_id(),
88 &Message::ChannelUpdate(ref msg) => msg.type_id(),
89 &Message::Unknown(type_id) => type_id,
95 /// Returns whether the message type is even, indicating both endpoints must support it.
96 pub fn is_even(&self) -> bool {
101 impl ::std::fmt::Display for MessageType {
102 fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
103 write!(f, "{}", self.0)
107 /// Reads a message from the data buffer consisting of a 2-byte big-endian type and a
108 /// variable-length payload conforming to the type.
112 /// Returns an error if the message payload code not be decoded as the specified type.
113 pub fn read<R: ::std::io::Read>(buffer: &mut R) -> Result<Message, msgs::DecodeError> {
114 let message_type = <u16 as Readable>::read(buffer)?;
116 msgs::Init::TYPE => {
117 Ok(Message::Init(Readable::read(buffer)?))
119 msgs::ErrorMessage::TYPE => {
120 Ok(Message::Error(Readable::read(buffer)?))
122 msgs::Ping::TYPE => {
123 Ok(Message::Ping(Readable::read(buffer)?))
125 msgs::Pong::TYPE => {
126 Ok(Message::Pong(Readable::read(buffer)?))
128 msgs::OpenChannel::TYPE => {
129 Ok(Message::OpenChannel(Readable::read(buffer)?))
131 msgs::AcceptChannel::TYPE => {
132 Ok(Message::AcceptChannel(Readable::read(buffer)?))
134 msgs::FundingCreated::TYPE => {
135 Ok(Message::FundingCreated(Readable::read(buffer)?))
137 msgs::FundingSigned::TYPE => {
138 Ok(Message::FundingSigned(Readable::read(buffer)?))
140 msgs::FundingLocked::TYPE => {
141 Ok(Message::FundingLocked(Readable::read(buffer)?))
143 msgs::Shutdown::TYPE => {
144 Ok(Message::Shutdown(Readable::read(buffer)?))
146 msgs::ClosingSigned::TYPE => {
147 Ok(Message::ClosingSigned(Readable::read(buffer)?))
149 msgs::UpdateAddHTLC::TYPE => {
150 Ok(Message::UpdateAddHTLC(Readable::read(buffer)?))
152 msgs::UpdateFulfillHTLC::TYPE => {
153 Ok(Message::UpdateFulfillHTLC(Readable::read(buffer)?))
155 msgs::UpdateFailHTLC::TYPE => {
156 Ok(Message::UpdateFailHTLC(Readable::read(buffer)?))
158 msgs::UpdateFailMalformedHTLC::TYPE => {
159 Ok(Message::UpdateFailMalformedHTLC(Readable::read(buffer)?))
161 msgs::CommitmentSigned::TYPE => {
162 Ok(Message::CommitmentSigned(Readable::read(buffer)?))
164 msgs::RevokeAndACK::TYPE => {
165 Ok(Message::RevokeAndACK(Readable::read(buffer)?))
167 msgs::UpdateFee::TYPE => {
168 Ok(Message::UpdateFee(Readable::read(buffer)?))
170 msgs::ChannelReestablish::TYPE => {
171 Ok(Message::ChannelReestablish(Readable::read(buffer)?))
173 msgs::AnnouncementSignatures::TYPE => {
174 Ok(Message::AnnouncementSignatures(Readable::read(buffer)?))
176 msgs::ChannelAnnouncement::TYPE => {
177 Ok(Message::ChannelAnnouncement(Readable::read(buffer)?))
179 msgs::NodeAnnouncement::TYPE => {
180 Ok(Message::NodeAnnouncement(Readable::read(buffer)?))
182 msgs::ChannelUpdate::TYPE => {
183 Ok(Message::ChannelUpdate(Readable::read(buffer)?))
186 Ok(Message::Unknown(MessageType(message_type)))
191 /// Writes a message to the data buffer encoded as a 2-byte big-endian type and a variable-length
196 /// Returns an I/O error if the write could not be completed.
197 pub fn write<M: Encode + Writeable, W: Writer>(message: &M, buffer: &mut W) -> Result<(), ::std::io::Error> {
198 M::TYPE.write(buffer)?;
199 message.write(buffer)
202 /// Defines a type-identified encoding for sending messages over the wire.
204 /// Messages implementing this trait specify a type and must be [`Writeable`] to use with [`write`].
206 /// [`Writeable`]: ../../util/ser/trait.Writeable.html
207 /// [`write`]: fn.write.html
209 /// The type identifying the message payload.
212 /// Returns the type identifying the message payload. Convenience method for accessing
214 fn type_id(&self) -> MessageType {
215 MessageType(Self::TYPE)
219 impl Encode for msgs::Init {
220 const TYPE: u16 = 16;
223 impl Encode for msgs::ErrorMessage {
224 const TYPE: u16 = 17;
227 impl Encode for msgs::Ping {
228 const TYPE: u16 = 18;
231 impl Encode for msgs::Pong {
232 const TYPE: u16 = 19;
235 impl Encode for msgs::OpenChannel {
236 const TYPE: u16 = 32;
239 impl Encode for msgs::AcceptChannel {
240 const TYPE: u16 = 33;
243 impl Encode for msgs::FundingCreated {
244 const TYPE: u16 = 34;
247 impl Encode for msgs::FundingSigned {
248 const TYPE: u16 = 35;
251 impl Encode for msgs::FundingLocked {
252 const TYPE: u16 = 36;
255 impl Encode for msgs::Shutdown {
256 const TYPE: u16 = 38;
259 impl Encode for msgs::ClosingSigned {
260 const TYPE: u16 = 39;
263 impl Encode for msgs::UpdateAddHTLC {
264 const TYPE: u16 = 128;
267 impl Encode for msgs::UpdateFulfillHTLC {
268 const TYPE: u16 = 130;
271 impl Encode for msgs::UpdateFailHTLC {
272 const TYPE: u16 = 131;
275 impl Encode for msgs::UpdateFailMalformedHTLC {
276 const TYPE: u16 = 135;
279 impl Encode for msgs::CommitmentSigned {
280 const TYPE: u16 = 132;
283 impl Encode for msgs::RevokeAndACK {
284 const TYPE: u16 = 133;
287 impl Encode for msgs::UpdateFee {
288 const TYPE: u16 = 134;
291 impl Encode for msgs::ChannelReestablish {
292 const TYPE: u16 = 136;
295 impl Encode for msgs::AnnouncementSignatures {
296 const TYPE: u16 = 259;
299 impl Encode for msgs::ChannelAnnouncement {
300 const TYPE: u16 = 256;
303 impl Encode for msgs::NodeAnnouncement {
304 const TYPE: u16 = 257;
307 impl Encode for msgs::ChannelUpdate {
308 const TYPE: u16 = 258;
314 use util::byte_utils;
316 // Big-endian wire encoding of Pong message (type = 19, byteslen = 2).
317 const ENCODED_PONG: [u8; 6] = [0u8, 19u8, 0u8, 2u8, 0u8, 0u8];
321 assert_eq!(LN_MAX_MSG_LEN, 65535);
322 assert_eq!(LN_MAX_MSG_LEN, std::u16::MAX as usize);
326 fn read_empty_buffer() {
328 let mut reader = ::std::io::Cursor::new(buffer);
329 assert!(read(&mut reader).is_err());
333 fn read_incomplete_type() {
334 let buffer = &ENCODED_PONG[..1];
335 let mut reader = ::std::io::Cursor::new(buffer);
336 assert!(read(&mut reader).is_err());
340 fn read_empty_payload() {
341 let buffer = &ENCODED_PONG[..2];
342 let mut reader = ::std::io::Cursor::new(buffer);
343 assert!(read(&mut reader).is_err());
347 fn read_invalid_message() {
348 let buffer = &ENCODED_PONG[..4];
349 let mut reader = ::std::io::Cursor::new(buffer);
350 assert!(read(&mut reader).is_err());
354 fn read_known_message() {
355 let buffer = &ENCODED_PONG[..];
356 let mut reader = ::std::io::Cursor::new(buffer);
357 let message = read(&mut reader).unwrap();
359 Message::Pong(_) => (),
360 _ => panic!("Expected pong message; found message type: {}", message.type_id()),
365 fn read_unknown_message() {
366 let buffer = &byte_utils::be16_to_array(::std::u16::MAX);
367 let mut reader = ::std::io::Cursor::new(buffer);
368 let message = read(&mut reader).unwrap();
370 Message::Unknown(MessageType(::std::u16::MAX)) => (),
371 _ => panic!("Expected message type {}; found: {}", ::std::u16::MAX, message.type_id()),
376 fn write_message_with_type() {
377 let message = msgs::Pong { byteslen: 2u16 };
378 let mut buffer = Vec::new();
379 assert!(write(&message, &mut buffer).is_ok());
381 let type_length = ::std::mem::size_of::<u16>();
382 let (type_bytes, payload_bytes) = buffer.split_at(type_length);
383 assert_eq!(byte_utils::slice_to_be16(type_bytes), msgs::Pong::TYPE);
384 assert_eq!(payload_bytes, &ENCODED_PONG[type_length..]);
388 fn read_message_encoded_with_write() {
389 let message = msgs::Pong { byteslen: 2u16 };
390 let mut buffer = Vec::new();
391 assert!(write(&message, &mut buffer).is_ok());
393 let mut reader = ::std::io::Cursor::new(buffer);
394 let decoded_message = read(&mut reader).unwrap();
395 match decoded_message {
396 Message::Pong(msgs::Pong { byteslen: 2u16 }) => (),
397 Message::Pong(msgs::Pong { byteslen }) => {
398 panic!("Expected byteslen {}; found: {}", message.byteslen, byteslen);
400 _ => panic!("Expected pong message; found message type: {}", decoded_message.type_id()),
405 fn is_even_message_type() {
406 let message = Message::Unknown(MessageType(42));
407 assert!(message.type_id().is_even());
411 fn is_odd_message_type() {
412 let message = Message::Unknown(MessageType(43));
413 assert!(!message.type_id().is_even());
417 fn read_lnd_init_msg() {
418 // Taken from lnd v0.9.0-beta.
419 let buffer = vec![0, 16, 0, 2, 34, 0, 0, 3, 2, 162, 161];
420 check_init_msg(buffer);
424 fn read_clightning_init_msg() {
425 // Taken from c-lightning v0.8.0.
426 let buffer = vec![0, 16, 0, 2, 34, 0, 0, 3, 2, 170, 162, 1, 32, 6, 34, 110, 70, 17, 26, 11, 89, 202, 175, 18, 96, 67, 235, 91, 191, 40, 195, 79, 58, 94, 51, 42, 31, 199, 178, 183, 60, 241, 136, 145, 15];
427 check_init_msg(buffer);
430 fn check_init_msg(buffer: Vec<u8>) {
431 let mut reader = ::std::io::Cursor::new(buffer);
432 let decoded_msg = read(&mut reader).unwrap();
434 Message::Init(msgs::Init { features }) => {
435 assert!(features.supports_variable_length_onion());
436 assert!(features.supports_upfront_shutdown_script());
437 assert!(features.supports_unknown_bits());
438 assert!(!features.requires_unknown_bits());
439 assert!(!features.initial_routing_sync());
441 _ => panic!("Expected init message, found message type: {}", decoded_msg.type_id())
446 fn read_lnd_node_announcement() {
447 // Taken from lnd v0.9.0-beta.
448 let buffer = vec![1, 1, 91, 164, 146, 213, 213, 165, 21, 227, 102, 33, 105, 179, 214, 21, 221, 175, 228, 93, 57, 177, 191, 127, 107, 229, 31, 50, 21, 81, 179, 71, 39, 18, 35, 2, 89, 224, 110, 123, 66, 39, 148, 246, 177, 85, 12, 19, 70, 226, 173, 132, 156, 26, 122, 146, 71, 213, 247, 48, 93, 190, 185, 177, 12, 172, 0, 3, 2, 162, 161, 94, 103, 195, 37, 2, 37, 242, 97, 140, 2, 111, 69, 85, 39, 118, 30, 221, 99, 254, 120, 49, 103, 22, 170, 227, 111, 172, 164, 160, 49, 68, 138, 116, 16, 22, 206, 107, 51, 153, 255, 97, 108, 105, 99, 101, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 1, 172, 21, 0, 2, 38, 7];
449 let mut reader = ::std::io::Cursor::new(buffer);
450 let decoded_msg = read(&mut reader).unwrap();
452 Message::NodeAnnouncement(msgs::NodeAnnouncement { contents: msgs::UnsignedNodeAnnouncement { features, ..}, ..}) => {
453 assert!(features.supports_variable_length_onion());
454 assert!(features.supports_upfront_shutdown_script());
455 assert!(features.supports_unknown_bits());
456 assert!(!features.requires_unknown_bits());
458 _ => panic!("Expected node announcement, found message type: {}", decoded_msg.type_id())
463 fn read_lnd_chan_announcement() {
464 // Taken from lnd v0.9.0-beta.
465 let buffer = vec![1, 0, 82, 238, 153, 33, 128, 87, 215, 2, 28, 241, 140, 250, 98, 255, 56, 5, 79, 240, 214, 231, 172, 35, 240, 171, 44, 9, 78, 91, 8, 193, 102, 5, 17, 178, 142, 106, 180, 183, 46, 38, 217, 212, 25, 236, 69, 47, 92, 217, 181, 221, 161, 205, 121, 201, 99, 38, 158, 216, 186, 193, 230, 86, 222, 6, 206, 67, 22, 255, 137, 212, 141, 161, 62, 134, 76, 48, 241, 54, 50, 167, 187, 247, 73, 27, 74, 1, 129, 185, 197, 153, 38, 90, 255, 138, 39, 161, 102, 172, 213, 74, 107, 88, 150, 90, 0, 49, 104, 7, 182, 184, 194, 219, 181, 172, 8, 245, 65, 226, 19, 228, 101, 145, 25, 159, 52, 31, 58, 93, 53, 59, 218, 91, 37, 84, 103, 17, 74, 133, 33, 35, 2, 203, 101, 73, 19, 94, 175, 122, 46, 224, 47, 168, 128, 128, 25, 26, 25, 214, 52, 247, 43, 241, 117, 52, 206, 94, 135, 156, 52, 164, 143, 234, 58, 185, 50, 185, 140, 198, 174, 71, 65, 18, 105, 70, 131, 172, 137, 0, 164, 51, 215, 143, 117, 119, 217, 241, 197, 177, 227, 227, 170, 199, 114, 7, 218, 12, 107, 30, 191, 236, 203, 21, 61, 242, 48, 192, 90, 233, 200, 199, 111, 162, 68, 234, 54, 219, 1, 233, 66, 5, 82, 74, 84, 211, 95, 199, 245, 202, 89, 223, 102, 124, 62, 166, 253, 253, 90, 180, 118, 21, 61, 110, 37, 5, 96, 167, 0, 0, 6, 34, 110, 70, 17, 26, 11, 89, 202, 175, 18, 96, 67, 235, 91, 191, 40, 195, 79, 58, 94, 51, 42, 31, 199, 178, 183, 60, 241, 136, 145, 15, 0, 2, 65, 0, 0, 1, 0, 0, 2, 37, 242, 97, 140, 2, 111, 69, 85, 39, 118, 30, 221, 99, 254, 120, 49, 103, 22, 170, 227, 111, 172, 164, 160, 49, 68, 138, 116, 16, 22, 206, 107, 3, 54, 61, 144, 88, 171, 247, 136, 208, 99, 9, 135, 37, 201, 178, 253, 136, 0, 185, 235, 68, 160, 106, 110, 12, 46, 21, 125, 204, 18, 75, 234, 16, 3, 42, 171, 28, 52, 224, 11, 30, 30, 253, 156, 148, 175, 203, 121, 250, 111, 122, 195, 84, 122, 77, 183, 56, 135, 101, 88, 41, 60, 191, 99, 232, 85, 2, 36, 17, 156, 11, 8, 12, 189, 177, 68, 88, 28, 15, 207, 21, 179, 151, 56, 226, 158, 148, 3, 120, 113, 177, 243, 184, 17, 173, 37, 46, 222, 16];
466 let mut reader = ::std::io::Cursor::new(buffer);
467 let decoded_msg = read(&mut reader).unwrap();
469 Message::ChannelAnnouncement(msgs::ChannelAnnouncement { contents: msgs::UnsignedChannelAnnouncement { features, ..}, ..}) => {
470 assert!(!features.requires_unknown_bits());
472 _ => panic!("Expected node announcement, found message type: {}", decoded_msg.type_id())