_ Git - rust-lightning/blob - lightning/src/ln/wire.rs

   1 //! Wire encoding/decoding for Lightning messages according to [BOLT #1].
   2 //!
   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.
   6 //!
   7 //! Messages implementing the [`Encode`] trait define a message type and can be sent over the wire
   8 //! using [`write`].
   9 //!
  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
  15
  16 use ln::msgs;
  17 use util::ser::{Readable, Writeable, Writer};
  18
  19 /// A Lightning message returned by [`read`] when decoding bytes received over the wire. Each
  20 /// variant contains a message from [`ln::msgs`] or otherwise the message type if unknown.
  21 ///
  22 /// [`read`]: fn.read.html
  23 /// [`ln::msgs`]: ../msgs/index.html
  24 #[allow(missing_docs)]
  25 pub enum Message {
  26         Init(msgs::Init),
  27         Error(msgs::ErrorMessage),
  28         Ping(msgs::Ping),
  29         Pong(msgs::Pong),
  30         OpenChannel(msgs::OpenChannel),
  31         AcceptChannel(msgs::AcceptChannel),
  32         FundingCreated(msgs::FundingCreated),
  33         FundingSigned(msgs::FundingSigned),
  34         FundingLocked(msgs::FundingLocked),
  35         Shutdown(msgs::Shutdown),
  36         ClosingSigned(msgs::ClosingSigned),
  37         UpdateAddHTLC(msgs::UpdateAddHTLC),
  38         UpdateFulfillHTLC(msgs::UpdateFulfillHTLC),
  39         UpdateFailHTLC(msgs::UpdateFailHTLC),
  40         UpdateFailMalformedHTLC(msgs::UpdateFailMalformedHTLC),
  41         CommitmentSigned(msgs::CommitmentSigned),
  42         RevokeAndACK(msgs::RevokeAndACK),
  43         UpdateFee(msgs::UpdateFee),
  44         ChannelReestablish(msgs::ChannelReestablish),
  45         AnnouncementSignatures(msgs::AnnouncementSignatures),
  46         ChannelAnnouncement(msgs::ChannelAnnouncement),
  47         NodeAnnouncement(msgs::NodeAnnouncement),
  48         ChannelUpdate(msgs::ChannelUpdate),
  49         /// A message that could not be decoded because its type is unknown.
  50         Unknown(MessageType),
  51 }
  52
  53 /// A number identifying a message to determine how it is encoded on the wire.
  54 #[derive(Clone, Copy)]
  55 pub struct MessageType(u16);
  56
  57 impl Message {
  58         /// Returns the type that was used to decode the message payload.
  59         pub fn type_id(&self) -> MessageType {
  60                 match self {
  61                         &Message::Init(ref msg) => msg.type_id(),
  62                         &Message::Error(ref msg) => msg.type_id(),
  63                         &Message::Ping(ref msg) => msg.type_id(),
  64                         &Message::Pong(ref msg) => msg.type_id(),
  65                         &Message::OpenChannel(ref msg) => msg.type_id(),
  66                         &Message::AcceptChannel(ref msg) => msg.type_id(),
  67                         &Message::FundingCreated(ref msg) => msg.type_id(),
  68                         &Message::FundingSigned(ref msg) => msg.type_id(),
  69                         &Message::FundingLocked(ref msg) => msg.type_id(),
  70                         &Message::Shutdown(ref msg) => msg.type_id(),
  71                         &Message::ClosingSigned(ref msg) => msg.type_id(),
  72                         &Message::UpdateAddHTLC(ref msg) => msg.type_id(),
  73                         &Message::UpdateFulfillHTLC(ref msg) => msg.type_id(),
  74                         &Message::UpdateFailHTLC(ref msg) => msg.type_id(),
  75                         &Message::UpdateFailMalformedHTLC(ref msg) => msg.type_id(),
  76                         &Message::CommitmentSigned(ref msg) => msg.type_id(),
  77                         &Message::RevokeAndACK(ref msg) => msg.type_id(),
  78                         &Message::UpdateFee(ref msg) => msg.type_id(),
  79                         &Message::ChannelReestablish(ref msg) => msg.type_id(),
  80                         &Message::AnnouncementSignatures(ref msg) => msg.type_id(),
  81                         &Message::ChannelAnnouncement(ref msg) => msg.type_id(),
  82                         &Message::NodeAnnouncement(ref msg) => msg.type_id(),
  83                         &Message::ChannelUpdate(ref msg) => msg.type_id(),
  84                         &Message::Unknown(type_id) => type_id,
  85                 }
  86         }
  87 }
  88
  89 impl MessageType {
  90         /// Returns whether the message type is even, indicating both endpoints must support it.
  91         pub fn is_even(&self) -> bool {
  92                 (self.0 & 1) == 0
  93         }
  94 }
  95
  96 impl ::std::fmt::Display for MessageType {
  97         fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
  98                 write!(f, "{}", self.0)
  99         }
 100 }
 101
 102 /// Reads a message from the data buffer consisting of a 2-byte big-endian type and a
 103 /// variable-length payload conforming to the type.
 104 ///
 105 /// # Errors
 106 ///
 107 /// Returns an error if the message payload code not be decoded as the specified type.
 108 pub fn read<R: ::std::io::Read>(buffer: &mut R) -> Result<Message, msgs::DecodeError> {
 109         let message_type = <u16 as Readable<R>>::read(buffer)?;
 110         match message_type {
 111                 msgs::Init::TYPE => {
 112                         Ok(Message::Init(Readable::read(buffer)?))
 113                 },
 114                 msgs::ErrorMessage::TYPE => {
 115                         Ok(Message::Error(Readable::read(buffer)?))
 116                 },
 117                 msgs::Ping::TYPE => {
 118                         Ok(Message::Ping(Readable::read(buffer)?))
 119                 },
 120                 msgs::Pong::TYPE => {
 121                         Ok(Message::Pong(Readable::read(buffer)?))
 122                 },
 123                 msgs::OpenChannel::TYPE => {
 124                         Ok(Message::OpenChannel(Readable::read(buffer)?))
 125                 },
 126                 msgs::AcceptChannel::TYPE => {
 127                         Ok(Message::AcceptChannel(Readable::read(buffer)?))
 128                 },
 129                 msgs::FundingCreated::TYPE => {
 130                         Ok(Message::FundingCreated(Readable::read(buffer)?))
 131                 },
 132                 msgs::FundingSigned::TYPE => {
 133                         Ok(Message::FundingSigned(Readable::read(buffer)?))
 134                 },
 135                 msgs::FundingLocked::TYPE => {
 136                         Ok(Message::FundingLocked(Readable::read(buffer)?))
 137                 },
 138                 msgs::Shutdown::TYPE => {
 139                         Ok(Message::Shutdown(Readable::read(buffer)?))
 140                 },
 141                 msgs::ClosingSigned::TYPE => {
 142                         Ok(Message::ClosingSigned(Readable::read(buffer)?))
 143                 },
 144                 msgs::UpdateAddHTLC::TYPE => {
 145                         Ok(Message::UpdateAddHTLC(Readable::read(buffer)?))
 146                 },
 147                 msgs::UpdateFulfillHTLC::TYPE => {
 148                         Ok(Message::UpdateFulfillHTLC(Readable::read(buffer)?))
 149                 },
 150                 msgs::UpdateFailHTLC::TYPE => {
 151                         Ok(Message::UpdateFailHTLC(Readable::read(buffer)?))
 152                 },
 153                 msgs::UpdateFailMalformedHTLC::TYPE => {
 154                         Ok(Message::UpdateFailMalformedHTLC(Readable::read(buffer)?))
 155                 },
 156                 msgs::CommitmentSigned::TYPE => {
 157                         Ok(Message::CommitmentSigned(Readable::read(buffer)?))
 158                 },
 159                 msgs::RevokeAndACK::TYPE => {
 160                         Ok(Message::RevokeAndACK(Readable::read(buffer)?))
 161                 },
 162                 msgs::UpdateFee::TYPE => {
 163                         Ok(Message::UpdateFee(Readable::read(buffer)?))
 164                 },
 165                 msgs::ChannelReestablish::TYPE => {
 166                         Ok(Message::ChannelReestablish(Readable::read(buffer)?))
 167                 },
 168                 msgs::AnnouncementSignatures::TYPE => {
 169                         Ok(Message::AnnouncementSignatures(Readable::read(buffer)?))
 170                 },
 171                 msgs::ChannelAnnouncement::TYPE => {
 172                         Ok(Message::ChannelAnnouncement(Readable::read(buffer)?))
 173                 },
 174                 msgs::NodeAnnouncement::TYPE => {
 175                         Ok(Message::NodeAnnouncement(Readable::read(buffer)?))
 176                 },
 177                 msgs::ChannelUpdate::TYPE => {
 178                         Ok(Message::ChannelUpdate(Readable::read(buffer)?))
 179                 },
 180                 _ => {
 181                         Ok(Message::Unknown(MessageType(message_type)))
 182                 },
 183         }
 184 }
 185
 186 /// Writes a message to the data buffer encoded as a 2-byte big-endian type and a variable-length
 187 /// payload.
 188 ///
 189 /// # Errors
 190 ///
 191 /// Returns an I/O error if the write could not be completed.
 192 pub fn write<M: Encode + Writeable, W: Writer>(message: &M, buffer: &mut W) -> Result<(), ::std::io::Error> {
 193         M::TYPE.write(buffer)?;
 194         message.write(buffer)
 195 }
 196
 197 /// Defines a type-identified encoding for sending messages over the wire.
 198 ///
 199 /// Messages implementing this trait specify a type and must be [`Writeable`] to use with [`write`].
 200 ///
 201 /// [`Writeable`]: ../../util/ser/trait.Writeable.html
 202 /// [`write`]: fn.write.html
 203 pub trait Encode {
 204         /// The type identifying the message payload.
 205         const TYPE: u16;
 206
 207         /// Returns the type identifying the message payload. Convenience method for accessing
 208         /// [`TYPE`](TYPE).
 209         fn type_id(&self) -> MessageType {
 210                 MessageType(Self::TYPE)
 211         }
 212 }
 213
 214 impl Encode for msgs::Init {
 215         const TYPE: u16 = 16;
 216 }
 217
 218 impl Encode for msgs::ErrorMessage {
 219         const TYPE: u16 = 17;
 220 }
 221
 222 impl Encode for msgs::Ping {
 223         const TYPE: u16 = 18;
 224 }
 225
 226 impl Encode for msgs::Pong {
 227         const TYPE: u16 = 19;
 228 }
 229
 230 impl Encode for msgs::OpenChannel {
 231         const TYPE: u16 = 32;
 232 }
 233
 234 impl Encode for msgs::AcceptChannel {
 235         const TYPE: u16 = 33;
 236 }
 237
 238 impl Encode for msgs::FundingCreated {
 239         const TYPE: u16 = 34;
 240 }
 241
 242 impl Encode for msgs::FundingSigned {
 243         const TYPE: u16 = 35;
 244 }
 245
 246 impl Encode for msgs::FundingLocked {
 247         const TYPE: u16 = 36;
 248 }
 249
 250 impl Encode for msgs::Shutdown {
 251         const TYPE: u16 = 38;
 252 }
 253
 254 impl Encode for msgs::ClosingSigned {
 255         const TYPE: u16 = 39;
 256 }
 257
 258 impl Encode for msgs::UpdateAddHTLC {
 259         const TYPE: u16 = 128;
 260 }
 261
 262 impl Encode for msgs::UpdateFulfillHTLC {
 263         const TYPE: u16 = 130;
 264 }
 265
 266 impl Encode for msgs::UpdateFailHTLC {
 267         const TYPE: u16 = 131;
 268 }
 269
 270 impl Encode for msgs::UpdateFailMalformedHTLC {
 271         const TYPE: u16 = 135;
 272 }
 273
 274 impl Encode for msgs::CommitmentSigned {
 275         const TYPE: u16 = 132;
 276 }
 277
 278 impl Encode for msgs::RevokeAndACK {
 279         const TYPE: u16 = 133;
 280 }
 281
 282 impl Encode for msgs::UpdateFee {
 283         const TYPE: u16 = 134;
 284 }
 285
 286 impl Encode for msgs::ChannelReestablish {
 287         const TYPE: u16 = 136;
 288 }
 289
 290 impl Encode for msgs::AnnouncementSignatures {
 291         const TYPE: u16 = 259;
 292 }
 293
 294 impl Encode for msgs::ChannelAnnouncement {
 295         const TYPE: u16 = 256;
 296 }
 297
 298 impl Encode for msgs::NodeAnnouncement {
 299         const TYPE: u16 = 257;
 300 }
 301
 302 impl Encode for msgs::ChannelUpdate {
 303         const TYPE: u16 = 258;
 304 }
 305
 306 #[cfg(test)]
 307 mod tests {
 308         use super::*;
 309         use util::byte_utils;
 310
 311         // Big-endian wire encoding of Pong message (type = 19, byteslen = 2).
 312         const ENCODED_PONG: [u8; 6] = [0u8, 19u8, 0u8, 2u8, 0u8, 0u8];
 313
 314         #[test]
 315         fn read_empty_buffer() {
 316                 let buffer = [];
 317                 let mut reader = ::std::io::Cursor::new(buffer);
 318                 assert!(read(&mut reader).is_err());
 319         }
 320
 321         #[test]
 322         fn read_incomplete_type() {
 323                 let buffer = &ENCODED_PONG[..1];
 324                 let mut reader = ::std::io::Cursor::new(buffer);
 325                 assert!(read(&mut reader).is_err());
 326         }
 327
 328         #[test]
 329         fn read_empty_payload() {
 330                 let buffer = &ENCODED_PONG[..2];
 331                 let mut reader = ::std::io::Cursor::new(buffer);
 332                 assert!(read(&mut reader).is_err());
 333         }
 334
 335         #[test]
 336         fn read_invalid_message() {
 337                 let buffer = &ENCODED_PONG[..4];
 338                 let mut reader = ::std::io::Cursor::new(buffer);
 339                 assert!(read(&mut reader).is_err());
 340         }
 341
 342         #[test]
 343         fn read_known_message() {
 344                 let buffer = &ENCODED_PONG[..];
 345                 let mut reader = ::std::io::Cursor::new(buffer);
 346                 let message = read(&mut reader).unwrap();
 347                 match message {
 348                         Message::Pong(_) => (),
 349                         _ => panic!("Expected pong message; found message type: {}", message.type_id()),
 350                 }
 351         }
 352
 353         #[test]
 354         fn read_unknown_message() {
 355                 let buffer = &byte_utils::be16_to_array(::std::u16::MAX);
 356                 let mut reader = ::std::io::Cursor::new(buffer);
 357                 let message = read(&mut reader).unwrap();
 358                 match message {
 359                         Message::Unknown(MessageType(::std::u16::MAX)) => (),
 360                         _ => panic!("Expected message type {}; found: {}", ::std::u16::MAX, message.type_id()),
 361                 }
 362         }
 363
 364         #[test]
 365         fn write_message_with_type() {
 366                 let message = msgs::Pong { byteslen: 2u16 };
 367                 let mut buffer = Vec::new();
 368                 assert!(write(&message, &mut buffer).is_ok());
 369
 370                 let type_length = ::std::mem::size_of::<u16>();
 371                 let (type_bytes, payload_bytes) = buffer.split_at(type_length);
 372                 assert_eq!(byte_utils::slice_to_be16(type_bytes), msgs::Pong::TYPE);
 373                 assert_eq!(payload_bytes, &ENCODED_PONG[type_length..]);
 374         }
 375
 376         #[test]
 377         fn read_message_encoded_with_write() {
 378                 let message = msgs::Pong { byteslen: 2u16 };
 379                 let mut buffer = Vec::new();
 380                 assert!(write(&message, &mut buffer).is_ok());
 381
 382                 let mut reader = ::std::io::Cursor::new(buffer);
 383                 let decoded_message = read(&mut reader).unwrap();
 384                 match decoded_message {
 385                         Message::Pong(msgs::Pong { byteslen: 2u16 }) => (),
 386                         Message::Pong(msgs::Pong { byteslen }) => {
 387                                 panic!("Expected byteslen {}; found: {}", message.byteslen, byteslen);
 388                         },
 389                         _ => panic!("Expected pong message; found message type: {}", decoded_message.type_id()),
 390                 }
 391         }
 392
 393         #[test]
 394         fn is_even_message_type() {
 395                 let message = Message::Unknown(MessageType(42));
 396                 assert!(message.type_id().is_even());
 397         }
 398
 399         #[test]
 400         fn is_odd_message_type() {
 401                 let message = Message::Unknown(MessageType(43));
 402                 assert!(!message.type_id().is_even());
 403         }
 404 }