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 /// "The maximum size of any Lightning message MUST NOT exceed 65535 bytes.
22 /// A maximum size of 65535 simplifies testing, makes memory management easier,
23 /// and helps mitigate memory-exhaustion attacks."
24 pub const LN_MAX_MSG_LEN: usize = std::u16::MAX as usize; // Must be equal to 65535
26 /// A Lightning message returned by [`read`] when decoding bytes received over the wire. Each
27 /// variant contains a message from [`ln::msgs`] or otherwise the message type if unknown.
29 /// [`read`]: fn.read.html
30 /// [`ln::msgs`]: ../msgs/index.html
31 #[allow(missing_docs)]
34 Error(msgs::ErrorMessage),
37 OpenChannel(msgs::OpenChannel),
38 AcceptChannel(msgs::AcceptChannel),
39 FundingCreated(msgs::FundingCreated),
40 FundingSigned(msgs::FundingSigned),
41 FundingLocked(msgs::FundingLocked),
42 Shutdown(msgs::Shutdown),
43 ClosingSigned(msgs::ClosingSigned),
44 UpdateAddHTLC(msgs::UpdateAddHTLC),
45 UpdateFulfillHTLC(msgs::UpdateFulfillHTLC),
46 UpdateFailHTLC(msgs::UpdateFailHTLC),
47 UpdateFailMalformedHTLC(msgs::UpdateFailMalformedHTLC),
48 CommitmentSigned(msgs::CommitmentSigned),
49 RevokeAndACK(msgs::RevokeAndACK),
50 UpdateFee(msgs::UpdateFee),
51 ChannelReestablish(msgs::ChannelReestablish),
52 AnnouncementSignatures(msgs::AnnouncementSignatures),
53 ChannelAnnouncement(msgs::ChannelAnnouncement),
54 NodeAnnouncement(msgs::NodeAnnouncement),
55 ChannelUpdate(msgs::ChannelUpdate),
56 /// A message that could not be decoded because its type is unknown.
60 /// A number identifying a message to determine how it is encoded on the wire.
61 #[derive(Clone, Copy)]
62 pub struct MessageType(u16);
65 /// Returns the type that was used to decode the message payload.
66 pub fn type_id(&self) -> MessageType {
68 &Message::Init(ref msg) => msg.type_id(),
69 &Message::Error(ref msg) => msg.type_id(),
70 &Message::Ping(ref msg) => msg.type_id(),
71 &Message::Pong(ref msg) => msg.type_id(),
72 &Message::OpenChannel(ref msg) => msg.type_id(),
73 &Message::AcceptChannel(ref msg) => msg.type_id(),
74 &Message::FundingCreated(ref msg) => msg.type_id(),
75 &Message::FundingSigned(ref msg) => msg.type_id(),
76 &Message::FundingLocked(ref msg) => msg.type_id(),
77 &Message::Shutdown(ref msg) => msg.type_id(),
78 &Message::ClosingSigned(ref msg) => msg.type_id(),
79 &Message::UpdateAddHTLC(ref msg) => msg.type_id(),
80 &Message::UpdateFulfillHTLC(ref msg) => msg.type_id(),
81 &Message::UpdateFailHTLC(ref msg) => msg.type_id(),
82 &Message::UpdateFailMalformedHTLC(ref msg) => msg.type_id(),
83 &Message::CommitmentSigned(ref msg) => msg.type_id(),
84 &Message::RevokeAndACK(ref msg) => msg.type_id(),
85 &Message::UpdateFee(ref msg) => msg.type_id(),
86 &Message::ChannelReestablish(ref msg) => msg.type_id(),
87 &Message::AnnouncementSignatures(ref msg) => msg.type_id(),
88 &Message::ChannelAnnouncement(ref msg) => msg.type_id(),
89 &Message::NodeAnnouncement(ref msg) => msg.type_id(),
90 &Message::ChannelUpdate(ref msg) => msg.type_id(),
91 &Message::Unknown(type_id) => type_id,
97 /// Returns whether the message type is even, indicating both endpoints must support it.
98 pub fn is_even(&self) -> bool {
103 impl ::std::fmt::Display for MessageType {
104 fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
105 write!(f, "{}", self.0)
109 /// Reads a message from the data buffer consisting of a 2-byte big-endian type and a
110 /// variable-length payload conforming to the type.
114 /// Returns an error if the message payload code not be decoded as the specified type.
115 pub fn read<R: ::std::io::Read>(buffer: &mut R) -> Result<Message, msgs::DecodeError> {
116 let message_type = <u16 as Readable>::read(buffer)?;
118 msgs::Init::TYPE => {
119 Ok(Message::Init(Readable::read(buffer)?))
121 msgs::ErrorMessage::TYPE => {
122 Ok(Message::Error(Readable::read(buffer)?))
124 msgs::Ping::TYPE => {
125 Ok(Message::Ping(Readable::read(buffer)?))
127 msgs::Pong::TYPE => {
128 Ok(Message::Pong(Readable::read(buffer)?))
130 msgs::OpenChannel::TYPE => {
131 Ok(Message::OpenChannel(Readable::read(buffer)?))
133 msgs::AcceptChannel::TYPE => {
134 Ok(Message::AcceptChannel(Readable::read(buffer)?))
136 msgs::FundingCreated::TYPE => {
137 Ok(Message::FundingCreated(Readable::read(buffer)?))
139 msgs::FundingSigned::TYPE => {
140 Ok(Message::FundingSigned(Readable::read(buffer)?))
142 msgs::FundingLocked::TYPE => {
143 Ok(Message::FundingLocked(Readable::read(buffer)?))
145 msgs::Shutdown::TYPE => {
146 Ok(Message::Shutdown(Readable::read(buffer)?))
148 msgs::ClosingSigned::TYPE => {
149 Ok(Message::ClosingSigned(Readable::read(buffer)?))
151 msgs::UpdateAddHTLC::TYPE => {
152 Ok(Message::UpdateAddHTLC(Readable::read(buffer)?))
154 msgs::UpdateFulfillHTLC::TYPE => {
155 Ok(Message::UpdateFulfillHTLC(Readable::read(buffer)?))
157 msgs::UpdateFailHTLC::TYPE => {
158 Ok(Message::UpdateFailHTLC(Readable::read(buffer)?))
160 msgs::UpdateFailMalformedHTLC::TYPE => {
161 Ok(Message::UpdateFailMalformedHTLC(Readable::read(buffer)?))
163 msgs::CommitmentSigned::TYPE => {
164 Ok(Message::CommitmentSigned(Readable::read(buffer)?))
166 msgs::RevokeAndACK::TYPE => {
167 Ok(Message::RevokeAndACK(Readable::read(buffer)?))
169 msgs::UpdateFee::TYPE => {
170 Ok(Message::UpdateFee(Readable::read(buffer)?))
172 msgs::ChannelReestablish::TYPE => {
173 Ok(Message::ChannelReestablish(Readable::read(buffer)?))
175 msgs::AnnouncementSignatures::TYPE => {
176 Ok(Message::AnnouncementSignatures(Readable::read(buffer)?))
178 msgs::ChannelAnnouncement::TYPE => {
179 Ok(Message::ChannelAnnouncement(Readable::read(buffer)?))
181 msgs::NodeAnnouncement::TYPE => {
182 Ok(Message::NodeAnnouncement(Readable::read(buffer)?))
184 msgs::ChannelUpdate::TYPE => {
185 Ok(Message::ChannelUpdate(Readable::read(buffer)?))
188 Ok(Message::Unknown(MessageType(message_type)))
193 /// Writes a message to the data buffer encoded as a 2-byte big-endian type and a variable-length
198 /// Returns an I/O error if the write could not be completed.
199 pub fn write<M: Encode + Writeable, W: Writer>(message: &M, buffer: &mut W) -> Result<(), ::std::io::Error> {
200 M::TYPE.write(buffer)?;
201 message.write(buffer)
204 /// Defines a type-identified encoding for sending messages over the wire.
206 /// Messages implementing this trait specify a type and must be [`Writeable`] to use with [`write`].
208 /// [`Writeable`]: ../../util/ser/trait.Writeable.html
209 /// [`write`]: fn.write.html
211 /// The type identifying the message payload.
214 /// Returns the type identifying the message payload. Convenience method for accessing
216 fn type_id(&self) -> MessageType {
217 MessageType(Self::TYPE)
221 impl Encode for msgs::Init {
222 const TYPE: u16 = 16;
225 impl Encode for msgs::ErrorMessage {
226 const TYPE: u16 = 17;
229 impl Encode for msgs::Ping {
230 const TYPE: u16 = 18;
233 impl Encode for msgs::Pong {
234 const TYPE: u16 = 19;
237 impl Encode for msgs::OpenChannel {
238 const TYPE: u16 = 32;
241 impl Encode for msgs::AcceptChannel {
242 const TYPE: u16 = 33;
245 impl Encode for msgs::FundingCreated {
246 const TYPE: u16 = 34;
249 impl Encode for msgs::FundingSigned {
250 const TYPE: u16 = 35;
253 impl Encode for msgs::FundingLocked {
254 const TYPE: u16 = 36;
257 impl Encode for msgs::Shutdown {
258 const TYPE: u16 = 38;
261 impl Encode for msgs::ClosingSigned {
262 const TYPE: u16 = 39;
265 impl Encode for msgs::UpdateAddHTLC {
266 const TYPE: u16 = 128;
269 impl Encode for msgs::UpdateFulfillHTLC {
270 const TYPE: u16 = 130;
273 impl Encode for msgs::UpdateFailHTLC {
274 const TYPE: u16 = 131;
277 impl Encode for msgs::UpdateFailMalformedHTLC {
278 const TYPE: u16 = 135;
281 impl Encode for msgs::CommitmentSigned {
282 const TYPE: u16 = 132;
285 impl Encode for msgs::RevokeAndACK {
286 const TYPE: u16 = 133;
289 impl Encode for msgs::UpdateFee {
290 const TYPE: u16 = 134;
293 impl Encode for msgs::ChannelReestablish {
294 const TYPE: u16 = 136;
297 impl Encode for msgs::AnnouncementSignatures {
298 const TYPE: u16 = 259;
301 impl Encode for msgs::ChannelAnnouncement {
302 const TYPE: u16 = 256;
305 impl Encode for msgs::NodeAnnouncement {
306 const TYPE: u16 = 257;
309 impl Encode for msgs::ChannelUpdate {
310 const TYPE: u16 = 258;
316 use util::byte_utils;
318 // Big-endian wire encoding of Pong message (type = 19, byteslen = 2).
319 const ENCODED_PONG: [u8; 6] = [0u8, 19u8, 0u8, 2u8, 0u8, 0u8];
323 assert_eq!(LN_MAX_MSG_LEN, 65535);
324 assert_eq!(LN_MAX_MSG_LEN, std::u16::MAX as usize);
328 fn read_empty_buffer() {
330 let mut reader = ::std::io::Cursor::new(buffer);
331 assert!(read(&mut reader).is_err());
335 fn read_incomplete_type() {
336 let buffer = &ENCODED_PONG[..1];
337 let mut reader = ::std::io::Cursor::new(buffer);
338 assert!(read(&mut reader).is_err());
342 fn read_empty_payload() {
343 let buffer = &ENCODED_PONG[..2];
344 let mut reader = ::std::io::Cursor::new(buffer);
345 assert!(read(&mut reader).is_err());
349 fn read_invalid_message() {
350 let buffer = &ENCODED_PONG[..4];
351 let mut reader = ::std::io::Cursor::new(buffer);
352 assert!(read(&mut reader).is_err());
356 fn read_known_message() {
357 let buffer = &ENCODED_PONG[..];
358 let mut reader = ::std::io::Cursor::new(buffer);
359 let message = read(&mut reader).unwrap();
361 Message::Pong(_) => (),
362 _ => panic!("Expected pong message; found message type: {}", message.type_id()),
367 fn read_unknown_message() {
368 let buffer = &byte_utils::be16_to_array(::std::u16::MAX);
369 let mut reader = ::std::io::Cursor::new(buffer);
370 let message = read(&mut reader).unwrap();
372 Message::Unknown(MessageType(::std::u16::MAX)) => (),
373 _ => panic!("Expected message type {}; found: {}", ::std::u16::MAX, message.type_id()),
378 fn write_message_with_type() {
379 let message = msgs::Pong { byteslen: 2u16 };
380 let mut buffer = Vec::new();
381 assert!(write(&message, &mut buffer).is_ok());
383 let type_length = ::std::mem::size_of::<u16>();
384 let (type_bytes, payload_bytes) = buffer.split_at(type_length);
385 assert_eq!(byte_utils::slice_to_be16(type_bytes), msgs::Pong::TYPE);
386 assert_eq!(payload_bytes, &ENCODED_PONG[type_length..]);
390 fn read_message_encoded_with_write() {
391 let message = msgs::Pong { byteslen: 2u16 };
392 let mut buffer = Vec::new();
393 assert!(write(&message, &mut buffer).is_ok());
395 let mut reader = ::std::io::Cursor::new(buffer);
396 let decoded_message = read(&mut reader).unwrap();
397 match decoded_message {
398 Message::Pong(msgs::Pong { byteslen: 2u16 }) => (),
399 Message::Pong(msgs::Pong { byteslen }) => {
400 panic!("Expected byteslen {}; found: {}", message.byteslen, byteslen);
402 _ => panic!("Expected pong message; found message type: {}", decoded_message.type_id()),
407 fn is_even_message_type() {
408 let message = Message::Unknown(MessageType(42));
409 assert!(message.type_id().is_even());
413 fn is_odd_message_type() {
414 let message = Message::Unknown(MessageType(43));
415 assert!(!message.type_id().is_even());
419 fn read_lnd_init_msg() {
420 // Taken from lnd v0.9.0-beta.
421 let buffer = vec![0, 16, 0, 2, 34, 0, 0, 3, 2, 162, 161];
422 check_init_msg(buffer);
426 fn read_clightning_init_msg() {
427 // Taken from c-lightning v0.8.0.
428 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];
429 check_init_msg(buffer);
432 fn check_init_msg(buffer: Vec<u8>) {
433 let mut reader = ::std::io::Cursor::new(buffer);
434 let decoded_msg = read(&mut reader).unwrap();
436 Message::Init(msgs::Init { features }) => {
437 assert!(features.supports_variable_length_onion());
438 assert!(features.supports_upfront_shutdown_script());
439 assert!(features.supports_unknown_bits());
440 assert!(!features.requires_unknown_bits());
441 assert!(!features.initial_routing_sync());
443 _ => panic!("Expected init message, found message type: {}", decoded_msg.type_id())
448 fn read_lnd_node_announcement() {
449 // Taken from lnd v0.9.0-beta.
450 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];
451 let mut reader = ::std::io::Cursor::new(buffer);
452 let decoded_msg = read(&mut reader).unwrap();
454 Message::NodeAnnouncement(msgs::NodeAnnouncement { contents: msgs::UnsignedNodeAnnouncement { features, ..}, ..}) => {
455 assert!(features.supports_variable_length_onion());
456 assert!(features.supports_upfront_shutdown_script());
457 assert!(features.supports_unknown_bits());
458 assert!(!features.requires_unknown_bits());
460 _ => panic!("Expected node announcement, found message type: {}", decoded_msg.type_id())
465 fn read_lnd_chan_announcement() {
466 // Taken from lnd v0.9.0-beta.
467 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];
468 let mut reader = ::std::io::Cursor::new(buffer);
469 let decoded_msg = read(&mut reader).unwrap();
471 Message::ChannelAnnouncement(msgs::ChannelAnnouncement { contents: msgs::UnsignedChannelAnnouncement { features, ..}, ..}) => {
472 assert!(!features.requires_unknown_bits());
474 _ => panic!("Expected node announcement, found message type: {}", decoded_msg.type_id())