_ Git - rust-lightning/blob - lightning/src/util/ser_macros.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! Some macros that implement [`Readable`]/[`Writeable`] traits for lightning messages.
  11 //! They also handle serialization and deserialization of TLVs.
  12 //!
  13 //! [`Readable`]: crate::util::ser::Readable
  14 //! [`Writeable`]: crate::util::ser::Writeable
  15
  16 /// Implements serialization for a single TLV record.
  17 /// This is exported for use by other exported macros, do not use directly.
  18 #[doc(hidden)]
  19 #[macro_export]
  20 macro_rules! _encode_tlv {
  21         ($stream: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
  22                 $crate::_encode_tlv!($stream, $type, $field, required)
  23         };
  24         ($stream: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
  25                 let _ = &$field; // Ensure we "use" the $field
  26         };
  27         ($stream: expr, $type: expr, $field: expr, required) => {
  28                 BigSize($type).write($stream)?;
  29                 BigSize($field.serialized_length() as u64).write($stream)?;
  30                 $field.write($stream)?;
  31         };
  32         ($stream: expr, $type: expr, $field: expr, required_vec) => {
  33                 $crate::_encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
  34         };
  35         ($stream: expr, $type: expr, $field: expr, vec_type) => {
  36                 $crate::_encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
  37         };
  38         ($stream: expr, $optional_type: expr, $optional_field: expr, option) => {
  39                 if let Some(ref field) = $optional_field {
  40                         BigSize($optional_type).write($stream)?;
  41                         BigSize(field.serialized_length() as u64).write($stream)?;
  42                         field.write($stream)?;
  43                 }
  44         };
  45         ($stream: expr, $type: expr, $field: expr, optional_vec) => {
  46                 if !$field.is_empty() {
  47                         $crate::_encode_tlv!($stream, $type, $field, required_vec);
  48                 }
  49         };
  50         ($stream: expr, $type: expr, $field: expr, upgradable_required) => {
  51                 $crate::_encode_tlv!($stream, $type, $field, required);
  52         };
  53         ($stream: expr, $type: expr, $field: expr, upgradable_option) => {
  54                 $crate::_encode_tlv!($stream, $type, $field, option);
  55         };
  56         ($stream: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
  57                 $crate::_encode_tlv!($stream, $type, $field.map(|f| $encoding(f)), option);
  58         };
  59         ($stream: expr, $type: expr, $field: expr, (option, encoding: $fieldty: ty)) => {
  60                 $crate::_encode_tlv!($stream, $type, $field, option);
  61         };
  62         ($stream: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
  63                 // Just a read-mapped type
  64                 $crate::_encode_tlv!($stream, $type, $field, option);
  65         };
  66 }
  67
  68 /// Panics if the last seen TLV type is not numerically less than the TLV type currently being checked.
  69 /// This is exported for use by other exported macros, do not use directly.
  70 #[doc(hidden)]
  71 #[macro_export]
  72 macro_rules! _check_encoded_tlv_order {
  73         ($last_type: expr, $type: expr, (static_value, $value: expr)) => { };
  74         ($last_type: expr, $type: expr, $fieldty: tt) => {
  75                 if let Some(t) = $last_type {
  76                         #[allow(unused_comparisons)] // Note that $type may be 0 making the following comparison always false
  77                         (debug_assert!(t < $type))
  78                 }
  79                 $last_type = Some($type);
  80         };
  81 }
  82
  83 /// Implements the TLVs serialization part in a [`Writeable`] implementation of a struct.
  84 ///
  85 /// This should be called inside a method which returns `Result<_, `[`io::Error`]`>`, such as
  86 /// [`Writeable::write`]. It will only return an `Err` if the stream `Err`s or [`Writeable::write`]
  87 /// on one of the fields `Err`s.
  88 ///
  89 /// `$stream` must be a `&mut `[`Writer`] which will receive the bytes for each TLV in the stream.
  90 ///
  91 /// Fields MUST be sorted in `$type`-order.
  92 ///
  93 /// Note that the lightning TLV requirements require that a single type not appear more than once,
  94 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
  95 /// decoder.
  96 ///
  97 /// Any `option` fields which have a value of `None` will not be serialized at all.
  98 ///
  99 /// For example,
 100 /// ```
 101 /// # use lightning::encode_tlv_stream;
 102 /// # fn write<W: lightning::util::ser::Writer> (stream: &mut W) -> Result<(), lightning::io::Error> {
 103 /// let mut required_value = 0u64;
 104 /// let mut optional_value: Option<u64> = None;
 105 /// encode_tlv_stream!(stream, {
 106 ///     (0, required_value, required),
 107 ///     (1, Some(42u64), option),
 108 ///     (2, optional_value, option),
 109 /// });
 110 /// // At this point `required_value` has been written as a TLV of type 0, `42u64` has been written
 111 /// // as a TLV of type 1 (indicating the reader may ignore it if it is not understood), and *no*
 112 /// // TLV is written with type 2.
 113 /// # Ok(())
 114 /// # }
 115 /// ```
 116 ///
 117 /// [`Writeable`]: crate::util::ser::Writeable
 118 /// [`io::Error`]: crate::io::Error
 119 /// [`Writeable::write`]: crate::util::ser::Writeable::write
 120 /// [`Writer`]: crate::util::ser::Writer
 121 #[macro_export]
 122 macro_rules! encode_tlv_stream {
 123         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => { {
 124                 #[allow(unused_imports)]
 125                 use $crate::{
 126                         ln::msgs::DecodeError,
 127                         util::ser,
 128                         util::ser::BigSize,
 129                         util::ser::Writeable,
 130                 };
 131
 132                 $(
 133                         $crate::_encode_tlv!($stream, $type, $field, $fieldty);
 134                 )*
 135
 136                 #[allow(unused_mut, unused_variables, unused_assignments)]
 137                 #[cfg(debug_assertions)]
 138                 {
 139                         let mut last_seen: Option<u64> = None;
 140                         $(
 141                                 $crate::_check_encoded_tlv_order!(last_seen, $type, $fieldty);
 142                         )*
 143                 }
 144         } }
 145 }
 146
 147 /// Adds the length of the serialized field to a [`LengthCalculatingWriter`].
 148 /// This is exported for use by other exported macros, do not use directly.
 149 ///
 150 /// [`LengthCalculatingWriter`]: crate::util::ser::LengthCalculatingWriter
 151 #[doc(hidden)]
 152 #[macro_export]
 153 macro_rules! _get_varint_length_prefixed_tlv_length {
 154         ($len: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
 155                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required)
 156         };
 157         ($len: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
 158         };
 159         ($len: expr, $type: expr, $field: expr, required) => {
 160                 BigSize($type).write(&mut $len).expect("No in-memory data may fail to serialize");
 161                 let field_len = $field.serialized_length();
 162                 BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
 163                 $len.0 += field_len;
 164         };
 165         ($len: expr, $type: expr, $field: expr, required_vec) => {
 166                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
 167         };
 168         ($len: expr, $type: expr, $field: expr, vec_type) => {
 169                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
 170         };
 171         ($len: expr, $optional_type: expr, $optional_field: expr, option) => {
 172                 if let Some(ref field) = $optional_field {
 173                         BigSize($optional_type).write(&mut $len).expect("No in-memory data may fail to serialize");
 174                         let field_len = field.serialized_length();
 175                         BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
 176                         $len.0 += field_len;
 177                 }
 178         };
 179         ($len: expr, $type: expr, $field: expr, optional_vec) => {
 180                 if !$field.is_empty() {
 181                         $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required_vec);
 182                 }
 183         };
 184         ($len: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
 185                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
 186         };
 187         ($len: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
 188                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field.map(|f| $encoding(f)), option);
 189         };
 190         ($len: expr, $type: expr, $field: expr, upgradable_required) => {
 191                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required);
 192         };
 193         ($len: expr, $type: expr, $field: expr, upgradable_option) => {
 194                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
 195         };
 196 }
 197
 198 /// See the documentation of [`write_tlv_fields`].
 199 /// This is exported for use by other exported macros, do not use directly.
 200 #[doc(hidden)]
 201 #[macro_export]
 202 macro_rules! _encode_varint_length_prefixed_tlv {
 203         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}) => { {
 204                 use $crate::util::ser::BigSize;
 205                 let len = {
 206                         #[allow(unused_mut)]
 207                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 208                         $(
 209                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, $field, $fieldty);
 210                         )*
 211                         len.0
 212                 };
 213                 BigSize(len as u64).write($stream)?;
 214                 $crate::encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* });
 215         } }
 216 }
 217
 218 /// Errors if there are missing required TLV types between the last seen type and the type currently being processed.
 219 /// This is exported for use by other exported macros, do not use directly.
 220 #[doc(hidden)]
 221 #[macro_export]
 222 macro_rules! _check_decoded_tlv_order {
 223         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 224                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 225                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 226                 if invalid_order {
 227                         $field = $default.into();
 228                 }
 229         }};
 230         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (static_value, $value: expr)) => {
 231         };
 232         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required) => {{
 233                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 234                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 235                 if invalid_order {
 236                         return Err(DecodeError::InvalidValue);
 237                 }
 238         }};
 239         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 240                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
 241         }};
 242         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
 243                 // no-op
 244         }};
 245         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required_vec) => {{
 246                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
 247         }};
 248         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, vec_type) => {{
 249                 // no-op
 250         }};
 251         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, optional_vec) => {{
 252                 // no-op
 253         }};
 254         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_required) => {{
 255                 _check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required)
 256         }};
 257         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_option) => {{
 258                 // no-op
 259         }};
 260         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 261                 // no-op
 262         }};
 263         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 264                 // no-op
 265         }};
 266 }
 267
 268 /// Errors if there are missing required TLV types after the last seen type.
 269 /// This is exported for use by other exported macros, do not use directly.
 270 #[doc(hidden)]
 271 #[macro_export]
 272 macro_rules! _check_missing_tlv {
 273         ($last_seen_type: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 274                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 275                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 276                 if missing_req_type {
 277                         $field = $default.into();
 278                 }
 279         }};
 280         ($last_seen_type: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
 281                 $field = $value;
 282         };
 283         ($last_seen_type: expr, $type: expr, $field: ident, required) => {{
 284                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 285                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 286                 if missing_req_type {
 287                         return Err(DecodeError::InvalidValue);
 288                 }
 289         }};
 290         ($last_seen_type: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 291                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 292         }};
 293         ($last_seen_type: expr, $type: expr, $field: ident, required_vec) => {{
 294                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 295         }};
 296         ($last_seen_type: expr, $type: expr, $field: ident, vec_type) => {{
 297                 // no-op
 298         }};
 299         ($last_seen_type: expr, $type: expr, $field: ident, option) => {{
 300                 // no-op
 301         }};
 302         ($last_seen_type: expr, $type: expr, $field: ident, optional_vec) => {{
 303                 // no-op
 304         }};
 305         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_required) => {{
 306                 _check_missing_tlv!($last_seen_type, $type, $field, required)
 307         }};
 308         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_option) => {{
 309                 // no-op
 310         }};
 311         ($last_seen_type: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 312                 // no-op
 313         }};
 314         ($last_seen_type: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 315                 // no-op
 316         }};
 317 }
 318
 319 /// Implements deserialization for a single TLV record.
 320 /// This is exported for use by other exported macros, do not use directly.
 321 #[doc(hidden)]
 322 #[macro_export]
 323 macro_rules! _decode_tlv {
 324         ($reader: expr, $field: ident, (default_value, $default: expr)) => {{
 325                 $crate::_decode_tlv!($reader, $field, required)
 326         }};
 327         ($reader: expr, $field: ident, (static_value, $value: expr)) => {{
 328         }};
 329         ($reader: expr, $field: ident, required) => {{
 330                 $field = $crate::util::ser::Readable::read(&mut $reader)?;
 331         }};
 332         ($reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 333                 $field = $trait::read(&mut $reader $(, $read_arg)*)?;
 334         }};
 335         ($reader: expr, $field: ident, required_vec) => {{
 336                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 337                 $field = f.0;
 338         }};
 339         ($reader: expr, $field: ident, vec_type) => {{
 340                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 341                 $field = Some(f.0);
 342         }};
 343         ($reader: expr, $field: ident, option) => {{
 344                 $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
 345         }};
 346         ($reader: expr, $field: ident, optional_vec) => {{
 347                 $crate::_decode_tlv!($reader, $field, vec_type);
 348         }};
 349         // `upgradable_required` indicates we're reading a required TLV that may have been upgraded
 350         // without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
 351         // field is present but we can no longer understand it.
 352         // Note that this variant can only be used within a `MaybeReadable` read.
 353         ($reader: expr, $field: ident, upgradable_required) => {{
 354                 $field = match $crate::util::ser::MaybeReadable::read(&mut $reader)? {
 355                         Some(res) => res,
 356                         _ => return Ok(None)
 357                 };
 358         }};
 359         // `upgradable_option` indicates we're reading an Option-al TLV that may have been upgraded
 360         // without backwards compat. $field will be None if the TLV is missing or if the field is present
 361         // but we can no longer understand it.
 362         ($reader: expr, $field: ident, upgradable_option) => {{
 363                 $field = $crate::util::ser::MaybeReadable::read(&mut $reader)?;
 364         }};
 365         ($reader: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 366                 $field = Some($trait::read(&mut $reader $(, $read_arg)*)?);
 367         }};
 368         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident, $encoder:ty))) => {{
 369                 $crate::_decode_tlv!($reader, $field, (option, encoding: ($fieldty, $encoding)));
 370         }};
 371         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {{
 372                 $field = {
 373                         let field: $encoding<$fieldty> = ser::Readable::read(&mut $reader)?;
 374                         Some(field.0)
 375                 };
 376         }};
 377         ($reader: expr, $field: ident, (option, encoding: $fieldty: ty)) => {{
 378                 $crate::_decode_tlv!($reader, $field, option);
 379         }};
 380 }
 381
 382 /// Checks if `$val` matches `$type`.
 383 /// This is exported for use by other exported macros, do not use directly.
 384 #[doc(hidden)]
 385 #[macro_export]
 386 macro_rules! _decode_tlv_stream_match_check {
 387         ($val: ident, $type: expr, (static_value, $value: expr)) => { false };
 388         ($val: ident, $type: expr, $fieldty: tt) => { $val == $type }
 389 }
 390
 391 /// Implements the TLVs deserialization part in a [`Readable`] implementation of a struct.
 392 ///
 393 /// This should be called inside a method which returns `Result<_, `[`DecodeError`]`>`, such as
 394 /// [`Readable::read`]. It will either return an `Err` or ensure all `required` fields have been
 395 /// read and optionally read `optional` fields.
 396 ///
 397 /// `$stream` must be a [`Read`] and will be fully consumed, reading until no more bytes remain
 398 /// (i.e. it returns [`DecodeError::ShortRead`]).
 399 ///
 400 /// Fields MUST be sorted in `$type`-order.
 401 ///
 402 /// Note that the lightning TLV requirements require that a single type not appear more than once,
 403 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
 404 /// decoder.
 405 ///
 406 /// For example,
 407 /// ```
 408 /// # use lightning::decode_tlv_stream;
 409 /// # fn read<R: lightning::io::Read> (stream: R) -> Result<(), lightning::ln::msgs::DecodeError> {
 410 /// let mut required_value = 0u64;
 411 /// let mut optional_value: Option<u64> = None;
 412 /// decode_tlv_stream!(stream, {
 413 ///     (0, required_value, required),
 414 ///     (2, optional_value, option),
 415 /// });
 416 /// // At this point, `required_value` has been overwritten with the TLV with type 0.
 417 /// // `optional_value` may have been overwritten, setting it to `Some` if a TLV with type 2 was
 418 /// // present.
 419 /// # Ok(())
 420 /// # }
 421 /// ```
 422 ///
 423 /// [`Readable`]: crate::util::ser::Readable
 424 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 425 /// [`Readable::read`]: crate::util::ser::Readable::read
 426 /// [`Read`]: crate::io::Read
 427 /// [`DecodeError::ShortRead`]: crate::ln::msgs::DecodeError::ShortRead
 428 #[macro_export]
 429 macro_rules! decode_tlv_stream {
 430         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 431                 let rewind = |_, _| { unreachable!() };
 432                 $crate::_decode_tlv_stream_range!($stream, .., rewind, {$(($type, $field, $fieldty)),*});
 433         }
 434 }
 435
 436 /// Similar to [`decode_tlv_stream`] with a custom TLV decoding capabilities.
 437 ///
 438 /// `$decode_custom_tlv` is a closure that may be optionally provided to handle custom message types.
 439 /// If it is provided, it will be called with the custom type and the [`FixedLengthReader`] containing
 440 /// the message contents. It should return `Ok(true)` if the custom message is successfully parsed,
 441 /// `Ok(false)` if the message type is unknown, and `Err(`[`DecodeError`]`)` if parsing fails.
 442 ///
 443 /// [`FixedLengthReader`]: crate::util::ser::FixedLengthReader
 444 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 445 macro_rules! decode_tlv_stream_with_custom_tlv_decode {
 446         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 447          $(, $decode_custom_tlv: expr)?) => { {
 448                 let rewind = |_, _| { unreachable!() };
 449                 _decode_tlv_stream_range!(
 450                         $stream, .., rewind, {$(($type, $field, $fieldty)),*} $(, $decode_custom_tlv)?
 451                 );
 452         } }
 453 }
 454
 455 #[doc(hidden)]
 456 #[macro_export]
 457 macro_rules! _decode_tlv_stream_range {
 458         ($stream: expr, $range: expr, $rewind: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 459          $(, $decode_custom_tlv: expr)?) => { {
 460                 use $crate::ln::msgs::DecodeError;
 461                 let mut last_seen_type: Option<u64> = None;
 462                 let mut stream_ref = $stream;
 463                 'tlv_read: loop {
 464                         use $crate::util::ser;
 465
 466                         // First decode the type of this TLV:
 467                         let typ: ser::BigSize = {
 468                                 // We track whether any bytes were read during the consensus_decode call to
 469                                 // determine whether we should break or return ShortRead if we get an
 470                                 // UnexpectedEof. This should in every case be largely cosmetic, but its nice to
 471                                 // pass the TLV test vectors exactly, which require this distinction.
 472                                 let mut tracking_reader = ser::ReadTrackingReader::new(&mut stream_ref);
 473                                 match <$crate::util::ser::BigSize as $crate::util::ser::Readable>::read(&mut tracking_reader) {
 474                                         Err(DecodeError::ShortRead) => {
 475                                                 if !tracking_reader.have_read {
 476                                                         break 'tlv_read;
 477                                                 } else {
 478                                                         return Err(DecodeError::ShortRead);
 479                                                 }
 480                                         },
 481                                         Err(e) => return Err(e),
 482                                         Ok(t) => if core::ops::RangeBounds::contains(&$range, &t.0) { t } else {
 483                                                 drop(tracking_reader);
 484
 485                                                 // Assumes the type id is minimally encoded, which is enforced on read.
 486                                                 use $crate::util::ser::Writeable;
 487                                                 let bytes_read = t.serialized_length();
 488                                                 $rewind(stream_ref, bytes_read);
 489                                                 break 'tlv_read;
 490                                         },
 491                                 }
 492                         };
 493
 494                         // Types must be unique and monotonically increasing:
 495                         match last_seen_type {
 496                                 Some(t) if typ.0 <= t => {
 497                                         return Err(DecodeError::InvalidValue);
 498                                 },
 499                                 _ => {},
 500                         }
 501                         // As we read types, make sure we hit every required type between `last_seen_type` and `typ`:
 502                         $({
 503                                 $crate::_check_decoded_tlv_order!(last_seen_type, typ, $type, $field, $fieldty);
 504                         })*
 505                         last_seen_type = Some(typ.0);
 506
 507                         // Finally, read the length and value itself:
 508                         let length: ser::BigSize = $crate::util::ser::Readable::read(&mut stream_ref)?;
 509                         let mut s = ser::FixedLengthReader::new(&mut stream_ref, length.0);
 510                         match typ.0 {
 511                                 $(_t if $crate::_decode_tlv_stream_match_check!(_t, $type, $fieldty) => {
 512                                         $crate::_decode_tlv!(s, $field, $fieldty);
 513                                         if s.bytes_remain() {
 514                                                 s.eat_remaining()?; // Return ShortRead if there's actually not enough bytes
 515                                                 return Err(DecodeError::InvalidValue);
 516                                         }
 517                                 },)*
 518                                 t => {
 519                                         $(
 520                                                 if $decode_custom_tlv(t, &mut s)? {
 521                                                         // If a custom TLV was successfully read (i.e. decode_custom_tlv returns true),
 522                                                         // continue to the next TLV read.
 523                                                         s.eat_remaining()?;
 524                                                         continue 'tlv_read;
 525                                                 }
 526                                         )?
 527                                         if t % 2 == 0 {
 528                                                 return Err(DecodeError::UnknownRequiredFeature);
 529                                         }
 530                                 }
 531                         }
 532                         s.eat_remaining()?;
 533                 }
 534                 // Make sure we got to each required type after we've read every TLV:
 535                 $({
 536                         $crate::_check_missing_tlv!(last_seen_type, $type, $field, $fieldty);
 537                 })*
 538         } }
 539 }
 540
 541 /// Implements [`Readable`]/[`Writeable`] for a message struct that may include non-TLV and
 542 /// TLV-encoded parts.
 543 ///
 544 /// This is useful to implement a [`CustomMessageReader`].
 545 ///
 546 /// Currently `$fieldty` may only be `option`, i.e., `$tlvfield` is optional field.
 547 ///
 548 /// For example,
 549 /// ```
 550 /// # use lightning::impl_writeable_msg;
 551 /// struct MyCustomMessage {
 552 ///     pub field_1: u32,
 553 ///     pub field_2: bool,
 554 ///     pub field_3: String,
 555 ///     pub tlv_optional_integer: Option<u32>,
 556 /// }
 557 ///
 558 /// impl_writeable_msg!(MyCustomMessage, {
 559 ///     field_1,
 560 ///     field_2,
 561 ///     field_3
 562 /// }, {
 563 ///     (1, tlv_optional_integer, option),
 564 /// });
 565 /// ```
 566 ///
 567 /// [`Readable`]: crate::util::ser::Readable
 568 /// [`Writeable`]: crate::util::ser::Writeable
 569 /// [`CustomMessageReader`]: crate::ln::wire::CustomMessageReader
 570 #[macro_export]
 571 macro_rules! impl_writeable_msg {
 572         ($st:ident, {$($field:ident),* $(,)*}, {$(($type: expr, $tlvfield: ident, $fieldty: tt)),* $(,)*}) => {
 573                 impl $crate::util::ser::Writeable for $st {
 574                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 575                                 $( self.$field.write(w)?; )*
 576                                 $crate::encode_tlv_stream!(w, {$(($type, self.$tlvfield.as_ref(), $fieldty)),*});
 577                                 Ok(())
 578                         }
 579                 }
 580                 impl $crate::util::ser::Readable for $st {
 581                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 582                                 $(let $field = $crate::util::ser::Readable::read(r)?;)*
 583                                 $($crate::_init_tlv_field_var!($tlvfield, $fieldty);)*
 584                                 $crate::decode_tlv_stream!(r, {$(($type, $tlvfield, $fieldty)),*});
 585                                 Ok(Self {
 586                                         $($field),*,
 587                                         $($tlvfield),*
 588                                 })
 589                         }
 590                 }
 591         }
 592 }
 593
 594 macro_rules! impl_writeable {
 595         ($st:ident, {$($field:ident),*}) => {
 596                 impl $crate::util::ser::Writeable for $st {
 597                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 598                                 $( self.$field.write(w)?; )*
 599                                 Ok(())
 600                         }
 601
 602                         #[inline]
 603                         fn serialized_length(&self) -> usize {
 604                                 let mut len_calc = 0;
 605                                 $( len_calc += self.$field.serialized_length(); )*
 606                                 return len_calc;
 607                         }
 608                 }
 609
 610                 impl $crate::util::ser::Readable for $st {
 611                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 612                                 Ok(Self {
 613                                         $($field: $crate::util::ser::Readable::read(r)?),*
 614                                 })
 615                         }
 616                 }
 617         }
 618 }
 619
 620 /// Write out two bytes to indicate the version of an object.
 621 ///
 622 /// $this_version represents a unique version of a type. Incremented whenever the type's
 623 /// serialization format has changed or has a new interpretation. Used by a type's reader to
 624 /// determine how to interpret fields or if it can understand a serialized object.
 625 ///
 626 /// $min_version_that_can_read_this is the minimum reader version which can understand this
 627 /// serialized object. Previous versions will simply err with a [`DecodeError::UnknownVersion`].
 628 ///
 629 /// Updates to either `$this_version` or `$min_version_that_can_read_this` should be included in
 630 /// release notes.
 631 ///
 632 /// Both version fields can be specific to this type of object.
 633 ///
 634 /// [`DecodeError::UnknownVersion`]: crate::ln::msgs::DecodeError::UnknownVersion
 635 macro_rules! write_ver_prefix {
 636         ($stream: expr, $this_version: expr, $min_version_that_can_read_this: expr) => {
 637                 $stream.write_all(&[$this_version; 1])?;
 638                 $stream.write_all(&[$min_version_that_can_read_this; 1])?;
 639         }
 640 }
 641
 642 /// Writes out a suffix to an object as a length-prefixed TLV stream which contains potentially
 643 /// backwards-compatible, optional fields which old nodes can happily ignore.
 644 ///
 645 /// It is written out in TLV format and, as with all TLV fields, unknown even fields cause a
 646 /// [`DecodeError::UnknownRequiredFeature`] error, with unknown odd fields ignored.
 647 ///
 648 /// This is the preferred method of adding new fields that old nodes can ignore and still function
 649 /// correctly.
 650 ///
 651 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
 652 #[macro_export]
 653 macro_rules! write_tlv_fields {
 654         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
 655                 $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*})
 656         }
 657 }
 658
 659 /// Reads a prefix added by [`write_ver_prefix`], above. Takes the current version of the
 660 /// serialization logic for this object. This is compared against the
 661 /// `$min_version_that_can_read_this` added by [`write_ver_prefix`].
 662 macro_rules! read_ver_prefix {
 663         ($stream: expr, $this_version: expr) => { {
 664                 let ver: u8 = Readable::read($stream)?;
 665                 let min_ver: u8 = Readable::read($stream)?;
 666                 if min_ver > $this_version {
 667                         return Err(DecodeError::UnknownVersion);
 668                 }
 669                 ver
 670         } }
 671 }
 672
 673 /// Reads a suffix added by [`write_tlv_fields`].
 674 ///
 675 /// [`write_tlv_fields`]: crate::write_tlv_fields
 676 #[macro_export]
 677 macro_rules! read_tlv_fields {
 678         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => { {
 679                 let tlv_len: $crate::util::ser::BigSize = $crate::util::ser::Readable::read($stream)?;
 680                 let mut rd = $crate::util::ser::FixedLengthReader::new($stream, tlv_len.0);
 681                 $crate::decode_tlv_stream!(&mut rd, {$(($type, $field, $fieldty)),*});
 682                 rd.eat_remaining().map_err(|_| $crate::ln::msgs::DecodeError::ShortRead)?;
 683         } }
 684 }
 685
 686 /// Initializes the struct fields.
 687 ///
 688 /// This is exported for use by other exported macros, do not use directly.
 689 #[doc(hidden)]
 690 #[macro_export]
 691 macro_rules! _init_tlv_based_struct_field {
 692         ($field: ident, (default_value, $default: expr)) => {
 693                 $field.0.unwrap()
 694         };
 695         ($field: ident, (static_value, $value: expr)) => {
 696                 $field
 697         };
 698         ($field: ident, option) => {
 699                 $field
 700         };
 701         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 702                 $crate::_init_tlv_based_struct_field!($field, option)
 703         };
 704         ($field: ident, upgradable_required) => {
 705                 $field.0.unwrap()
 706         };
 707         ($field: ident, upgradable_option) => {
 708                 $field
 709         };
 710         ($field: ident, required) => {
 711                 $field.0.unwrap()
 712         };
 713         ($field: ident, required_vec) => {
 714                 $field
 715         };
 716         ($field: ident, vec_type) => {
 717                 $field.unwrap()
 718         };
 719         ($field: ident, optional_vec) => {
 720                 $field.unwrap()
 721         };
 722 }
 723
 724 /// Initializes the variable we are going to read the TLV into.
 725 ///
 726 /// This is exported for use by other exported macros, do not use directly.
 727 #[doc(hidden)]
 728 #[macro_export]
 729 macro_rules! _init_tlv_field_var {
 730         ($field: ident, (default_value, $default: expr)) => {
 731                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 732         };
 733         ($field: ident, (static_value, $value: expr)) => {
 734                 let $field;
 735         };
 736         ($field: ident, required) => {
 737                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 738         };
 739         ($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
 740                 $crate::_init_tlv_field_var!($field, required);
 741         };
 742         ($field: ident, required_vec) => {
 743                 let mut $field = Vec::new();
 744         };
 745         ($field: ident, vec_type) => {
 746                 let mut $field = Some(Vec::new());
 747         };
 748         ($field: ident, option) => {
 749                 let mut $field = None;
 750         };
 751         ($field: ident, optional_vec) => {
 752                 let mut $field = Some(Vec::new());
 753         };
 754         ($field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
 755                 $crate::_init_tlv_field_var!($field, option);
 756         };
 757         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 758                 $crate::_init_tlv_field_var!($field, option);
 759         };
 760         ($field: ident, upgradable_required) => {
 761                 let mut $field = $crate::util::ser::UpgradableRequired(None);
 762         };
 763         ($field: ident, upgradable_option) => {
 764                 let mut $field = None;
 765         };
 766 }
 767
 768 /// Equivalent to running [`_init_tlv_field_var`] then [`read_tlv_fields`].
 769 ///
 770 /// This is exported for use by other exported macros, do not use directly.
 771 #[doc(hidden)]
 772 #[macro_export]
 773 macro_rules! _init_and_read_tlv_fields {
 774         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 775                 $(
 776                         $crate::_init_tlv_field_var!($field, $fieldty);
 777                 )*
 778
 779                 $crate::read_tlv_fields!($reader, {
 780                         $(($type, $field, $fieldty)),*
 781                 });
 782         }
 783 }
 784
 785 /// Implements [`Readable`]/[`Writeable`] for a struct storing it as a set of TLVs
 786 /// If `$fieldty` is `required`, then `$field` is a required field that is not an [`Option`] nor a [`Vec`].
 787 /// If `$fieldty` is `(default_value, $default)`, then `$field` will be set to `$default` if not present.
 788 /// If `$fieldty` is `option`, then `$field` is optional field.
 789 /// If `$fieldty` is `optional_vec`, then `$field` is a [`Vec`], which needs to have its individual elements serialized.
 790 ///    Note that for `optional_vec` no bytes are written if the vec is empty
 791 ///
 792 /// For example,
 793 /// ```
 794 /// # use lightning::impl_writeable_tlv_based;
 795 /// struct LightningMessage {
 796 ///     tlv_integer: u32,
 797 ///     tlv_default_integer: u32,
 798 ///     tlv_optional_integer: Option<u32>,
 799 ///     tlv_vec_type_integer: Vec<u32>,
 800 /// }
 801 ///
 802 /// impl_writeable_tlv_based!(LightningMessage, {
 803 ///     (0, tlv_integer, required),
 804 ///     (1, tlv_default_integer, (default_value, 7)),
 805 ///     (2, tlv_optional_integer, option),
 806 ///     (3, tlv_vec_type_integer, optional_vec),
 807 /// });
 808 /// ```
 809 ///
 810 /// [`Readable`]: crate::util::ser::Readable
 811 /// [`Writeable`]: crate::util::ser::Writeable
 812 #[macro_export]
 813 macro_rules! impl_writeable_tlv_based {
 814         ($st: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 815                 impl $crate::util::ser::Writeable for $st {
 816                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 817                                 $crate::write_tlv_fields!(writer, {
 818                                         $(($type, self.$field, $fieldty)),*
 819                                 });
 820                                 Ok(())
 821                         }
 822
 823                         #[inline]
 824                         fn serialized_length(&self) -> usize {
 825                                 use $crate::util::ser::BigSize;
 826                                 let len = {
 827                                         #[allow(unused_mut)]
 828                                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 829                                         $(
 830                                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, self.$field, $fieldty);
 831                                         )*
 832                                         len.0
 833                                 };
 834                                 let mut len_calc = $crate::util::ser::LengthCalculatingWriter(0);
 835                                 BigSize(len as u64).write(&mut len_calc).expect("No in-memory data may fail to serialize");
 836                                 len + len_calc.0
 837                         }
 838                 }
 839
 840                 impl $crate::util::ser::Readable for $st {
 841                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 842                                 $crate::_init_and_read_tlv_fields!(reader, {
 843                                         $(($type, $field, $fieldty)),*
 844                                 });
 845                                 Ok(Self {
 846                                         $(
 847                                                 $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
 848                                         ),*
 849                                 })
 850                         }
 851                 }
 852         }
 853 }
 854
 855 /// Defines a struct for a TLV stream and a similar struct using references for non-primitive types,
 856 /// implementing [`Readable`] for the former and [`Writeable`] for the latter. Useful as an
 857 /// intermediary format when reading or writing a type encoded as a TLV stream. Note that each field
 858 /// representing a TLV record has its type wrapped with an [`Option`]. A tuple consisting of a type
 859 /// and a serialization wrapper may be given in place of a type when custom serialization is
 860 /// required.
 861 ///
 862 /// [`Readable`]: crate::util::ser::Readable
 863 /// [`Writeable`]: crate::util::ser::Writeable
 864 macro_rules! tlv_stream {
 865         ($name:ident, $nameref:ident, $range:expr, {
 866                 $(($type:expr, $field:ident : $fieldty:tt)),* $(,)*
 867         }) => {
 868                 #[derive(Debug)]
 869                 pub(super) struct $name {
 870                         $(
 871                                 pub(super) $field: Option<tlv_record_type!($fieldty)>,
 872                         )*
 873                 }
 874
 875                 #[cfg_attr(test, derive(PartialEq))]
 876                 #[derive(Debug)]
 877                 pub(super) struct $nameref<'a> {
 878                         $(
 879                                 pub(super) $field: Option<tlv_record_ref_type!($fieldty)>,
 880                         )*
 881                 }
 882
 883                 impl<'a> $crate::util::ser::Writeable for $nameref<'a> {
 884                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 885                                 encode_tlv_stream!(writer, {
 886                                         $(($type, self.$field, (option, encoding: $fieldty))),*
 887                                 });
 888                                 Ok(())
 889                         }
 890                 }
 891
 892                 impl $crate::util::ser::SeekReadable for $name {
 893                         fn read<R: $crate::io::Read + $crate::io::Seek>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 894                                 $(
 895                                         _init_tlv_field_var!($field, option);
 896                                 )*
 897                                 let rewind = |cursor: &mut R, offset: usize| {
 898                                         cursor.seek($crate::io::SeekFrom::Current(-(offset as i64))).expect("");
 899                                 };
 900                                 _decode_tlv_stream_range!(reader, $range, rewind, {
 901                                         $(($type, $field, (option, encoding: $fieldty))),*
 902                                 });
 903
 904                                 Ok(Self {
 905                                         $(
 906                                                 $field: $field
 907                                         ),*
 908                                 })
 909                         }
 910                 }
 911         }
 912 }
 913
 914 macro_rules! tlv_record_type {
 915         (($type:ty, $wrapper:ident)) => { $type };
 916         (($type:ty, $wrapper:ident, $encoder:ty)) => { $type };
 917         ($type:ty) => { $type };
 918 }
 919
 920 macro_rules! tlv_record_ref_type {
 921         (char) => { char };
 922         (u8) => { u8 };
 923         ((u16, $wrapper: ident)) => { u16 };
 924         ((u32, $wrapper: ident)) => { u32 };
 925         ((u64, $wrapper: ident)) => { u64 };
 926         (($type:ty, $wrapper:ident)) => { &'a $type };
 927         (($type:ty, $wrapper:ident, $encoder:ty)) => { $encoder };
 928         ($type:ty) => { &'a $type };
 929 }
 930
 931 #[doc(hidden)]
 932 #[macro_export]
 933 macro_rules! _impl_writeable_tlv_based_enum_common {
 934         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 935                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 936         ),* $(,)*;
 937         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
 938                 impl $crate::util::ser::Writeable for $st {
 939                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 940                                 match self {
 941                                         $($st::$variant_name { $(ref $field),* } => {
 942                                                 let id: u8 = $variant_id;
 943                                                 id.write(writer)?;
 944                                                 $crate::write_tlv_fields!(writer, {
 945                                                         $(($type, *$field, $fieldty)),*
 946                                                 });
 947                                         }),*
 948                                         $($st::$tuple_variant_name (ref field) => {
 949                                                 let id: u8 = $tuple_variant_id;
 950                                                 id.write(writer)?;
 951                                                 field.write(writer)?;
 952                                         }),*
 953                                 }
 954                                 Ok(())
 955                         }
 956                 }
 957         }
 958 }
 959
 960 /// Implement [`Readable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and tuple
 961 /// variants stored directly.
 962 /// The format is, for example
 963 /// ```ignore
 964 /// impl_writeable_tlv_based_enum!(EnumName,
 965 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
 966 ///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, optional_vec)};
 967 ///   (2, TupleVariantA), (3, TupleVariantB),
 968 /// );
 969 /// ```
 970 /// The type is written as a single byte, followed by any variant data.
 971 /// Attempts to read an unknown type byte result in [`DecodeError::UnknownRequiredFeature`].
 972 ///
 973 /// [`Readable`]: crate::util::ser::Readable
 974 /// [`Writeable`]: crate::util::ser::Writeable
 975 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
 976 #[macro_export]
 977 macro_rules! impl_writeable_tlv_based_enum {
 978         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 979                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 980         ),* $(,)*;
 981         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
 982                 $crate::_impl_writeable_tlv_based_enum_common!($st,
 983                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
 984                         $(($tuple_variant_id, $tuple_variant_name)),*);
 985
 986                 impl $crate::util::ser::Readable for $st {
 987                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 988                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
 989                                 match id {
 990                                         $($variant_id => {
 991                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
 992                                                 // in the same function body. Instead, we define a closure and call it.
 993                                                 let f = || {
 994                                                         $crate::_init_and_read_tlv_fields!(reader, {
 995                                                                 $(($type, $field, $fieldty)),*
 996                                                         });
 997                                                         Ok($st::$variant_name {
 998                                                                 $(
 999                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1000                                                                 ),*
1001                                                         })
1002                                                 };
1003                                                 f()
1004                                         }),*
1005                                         $($tuple_variant_id => {
1006                                                 Ok($st::$tuple_variant_name(Readable::read(reader)?))
1007                                         }),*
1008                                         _ => {
1009                                                 Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature)
1010                                         },
1011                                 }
1012                         }
1013                 }
1014         }
1015 }
1016
1017 /// Implement [`MaybeReadable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and
1018 /// tuple variants stored directly.
1019 ///
1020 /// This is largely identical to [`impl_writeable_tlv_based_enum`], except that odd variants will
1021 /// return `Ok(None)` instead of `Err(`[`DecodeError::UnknownRequiredFeature`]`)`. It should generally be preferred
1022 /// when [`MaybeReadable`] is practical instead of just [`Readable`] as it provides an upgrade path for
1023 /// new variants to be added which are simply ignored by existing clients.
1024 ///
1025 /// [`MaybeReadable`]: crate::util::ser::MaybeReadable
1026 /// [`Writeable`]: crate::util::ser::Writeable
1027 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1028 /// [`Readable`]: crate::util::ser::Readable
1029 #[macro_export]
1030 macro_rules! impl_writeable_tlv_based_enum_upgradable {
1031         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1032                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1033         ),* $(,)*
1034         $(;
1035         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
1036                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1037                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1038                         $($(($tuple_variant_id, $tuple_variant_name)),*)*);
1039
1040                 impl $crate::util::ser::MaybeReadable for $st {
1041                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Option<Self>, $crate::ln::msgs::DecodeError> {
1042                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1043                                 match id {
1044                                         $($variant_id => {
1045                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1046                                                 // in the same function body. Instead, we define a closure and call it.
1047                                                 let f = || {
1048                                                         $crate::_init_and_read_tlv_fields!(reader, {
1049                                                                 $(($type, $field, $fieldty)),*
1050                                                         });
1051                                                         Ok(Some($st::$variant_name {
1052                                                                 $(
1053                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1054                                                                 ),*
1055                                                         }))
1056                                                 };
1057                                                 f()
1058                                         }),*
1059                                         $($($tuple_variant_id => {
1060                                                 Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
1061                                         }),*)*
1062                                         _ if id % 2 == 1 => Ok(None),
1063                                         _ => Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature),
1064                                 }
1065                         }
1066                 }
1067         }
1068 }
1069
1070 #[cfg(test)]
1071 mod tests {
1072         use crate::io::{self, Cursor};
1073         use crate::prelude::*;
1074         use crate::ln::msgs::DecodeError;
1075         use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
1076         use bitcoin::secp256k1::PublicKey;
1077
1078         // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
1079         // the encoding layer in the BOLTs has no such concept, though it makes our macros easier to
1080         // work with so they're baked into the decoder. Thus, we have a few additional tests below
1081         fn tlv_reader(s: &[u8]) -> Result<(u64, u32, Option<u32>), DecodeError> {
1082                 let mut s = Cursor::new(s);
1083                 let mut a: u64 = 0;
1084                 let mut b: u32 = 0;
1085                 let mut c: Option<u32> = None;
1086                 decode_tlv_stream!(&mut s, {(2, a, required), (3, b, required), (4, c, option)});
1087                 Ok((a, b, c))
1088         }
1089
1090         #[test]
1091         fn tlv_v_short_read() {
1092                 // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
1093                 if let Err(DecodeError::ShortRead) = tlv_reader(&::hex::decode(
1094                                 concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
1095                                 ).unwrap()[..]) {
1096                 } else { panic!(); }
1097         }
1098
1099         #[test]
1100         fn tlv_types_out_of_order() {
1101                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1102                                 concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
1103                                 ).unwrap()[..]) {
1104                 } else { panic!(); }
1105                 // ...even if its some field we don't understand
1106                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1107                                 concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
1108                                 ).unwrap()[..]) {
1109                 } else { panic!(); }
1110         }
1111
1112         #[test]
1113         fn tlv_req_type_missing_or_extra() {
1114                 // It's also bad if they included even fields we don't understand
1115                 if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&::hex::decode(
1116                                 concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
1117                                 ).unwrap()[..]) {
1118                 } else { panic!(); }
1119                 // ... or if they're missing fields we need
1120                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1121                                 concat!("0100", "0208deadbeef1badbeef")
1122                                 ).unwrap()[..]) {
1123                 } else { panic!(); }
1124                 // ... even if that field is even
1125                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1126                                 concat!("0304deadbeef", "0500")
1127                                 ).unwrap()[..]) {
1128                 } else { panic!(); }
1129         }
1130
1131         #[test]
1132         fn tlv_simple_good_cases() {
1133                 assert_eq!(tlv_reader(&::hex::decode(
1134                                 concat!("0208deadbeef1badbeef", "03041bad1dea")
1135                                 ).unwrap()[..]).unwrap(),
1136                         (0xdeadbeef1badbeef, 0x1bad1dea, None));
1137                 assert_eq!(tlv_reader(&::hex::decode(
1138                                 concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
1139                                 ).unwrap()[..]).unwrap(),
1140                         (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
1141         }
1142
1143         #[derive(Debug, PartialEq)]
1144         struct TestUpgradable {
1145                 a: u32,
1146                 b: u32,
1147                 c: Option<u32>,
1148         }
1149
1150         fn upgradable_tlv_reader(s: &[u8]) -> Result<Option<TestUpgradable>, DecodeError> {
1151                 let mut s = Cursor::new(s);
1152                 let mut a = 0;
1153                 let mut b = 0;
1154                 let mut c: Option<u32> = None;
1155                 decode_tlv_stream!(&mut s, {(2, a, upgradable_required), (3, b, upgradable_required), (4, c, upgradable_option)});
1156                 Ok(Some(TestUpgradable { a, b, c, }))
1157         }
1158
1159         #[test]
1160         fn upgradable_tlv_simple_good_cases() {
1161                 assert_eq!(upgradable_tlv_reader(&::hex::decode(
1162                         concat!("0204deadbeef", "03041bad1dea", "0404deadbeef")
1163                 ).unwrap()[..]).unwrap(),
1164                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: Some(0xdeadbeef) }));
1165
1166                 assert_eq!(upgradable_tlv_reader(&::hex::decode(
1167                         concat!("0204deadbeef", "03041bad1dea")
1168                 ).unwrap()[..]).unwrap(),
1169                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: None}));
1170         }
1171
1172         #[test]
1173         fn missing_required_upgradable() {
1174                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&::hex::decode(
1175                         concat!("0100", "0204deadbeef")
1176                         ).unwrap()[..]) {
1177                 } else { panic!(); }
1178                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&::hex::decode(
1179                         concat!("0100", "03041bad1dea")
1180                 ).unwrap()[..]) {
1181                 } else { panic!(); }
1182         }
1183
1184         // BOLT TLV test cases
1185         fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
1186                 let mut s = Cursor::new(s);
1187                 let mut tlv1: Option<HighZeroBytesDroppedBigSize<u64>> = None;
1188                 let mut tlv2: Option<u64> = None;
1189                 let mut tlv3: Option<(PublicKey, u64, u64)> = None;
1190                 let mut tlv4: Option<u16> = None;
1191                 decode_tlv_stream!(&mut s, {(1, tlv1, option), (2, tlv2, option), (3, tlv3, option), (254, tlv4, option)});
1192                 Ok((tlv1, tlv2, tlv3, tlv4))
1193         }
1194
1195         #[test]
1196         fn bolt_tlv_bogus_stream() {
1197                 macro_rules! do_test {
1198                         ($stream: expr, $reason: ident) => {
1199                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
1200                                 } else { panic!(); }
1201                         }
1202                 }
1203
1204                 // TLVs from the BOLT test cases which should not decode as either n1 or n2
1205                 do_test!(concat!("fd01"), ShortRead);
1206                 do_test!(concat!("fd0001", "00"), InvalidValue);
1207                 do_test!(concat!("fd0101"), ShortRead);
1208                 do_test!(concat!("0f", "fd"), ShortRead);
1209                 do_test!(concat!("0f", "fd26"), ShortRead);
1210                 do_test!(concat!("0f", "fd2602"), ShortRead);
1211                 do_test!(concat!("0f", "fd0001", "00"), InvalidValue);
1212                 do_test!(concat!("0f", "fd0201", "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"), ShortRead);
1213
1214                 do_test!(concat!("12", "00"), UnknownRequiredFeature);
1215                 do_test!(concat!("fd0102", "00"), UnknownRequiredFeature);
1216                 do_test!(concat!("fe01000002", "00"), UnknownRequiredFeature);
1217                 do_test!(concat!("ff0100000000000002", "00"), UnknownRequiredFeature);
1218         }
1219
1220         #[test]
1221         fn bolt_tlv_bogus_n1_stream() {
1222                 macro_rules! do_test {
1223                         ($stream: expr, $reason: ident) => {
1224                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
1225                                 } else { panic!(); }
1226                         }
1227                 }
1228
1229                 // TLVs from the BOLT test cases which should not decode as n1
1230                 do_test!(concat!("01", "09", "ffffffffffffffffff"), InvalidValue);
1231                 do_test!(concat!("01", "01", "00"), InvalidValue);
1232                 do_test!(concat!("01", "02", "0001"), InvalidValue);
1233                 do_test!(concat!("01", "03", "000100"), InvalidValue);
1234                 do_test!(concat!("01", "04", "00010000"), InvalidValue);
1235                 do_test!(concat!("01", "05", "0001000000"), InvalidValue);
1236                 do_test!(concat!("01", "06", "000100000000"), InvalidValue);
1237                 do_test!(concat!("01", "07", "00010000000000"), InvalidValue);
1238                 do_test!(concat!("01", "08", "0001000000000000"), InvalidValue);
1239                 do_test!(concat!("02", "07", "01010101010101"), ShortRead);
1240                 do_test!(concat!("02", "09", "010101010101010101"), InvalidValue);
1241                 do_test!(concat!("03", "21", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb"), ShortRead);
1242                 do_test!(concat!("03", "29", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001"), ShortRead);
1243                 do_test!(concat!("03", "30", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb000000000000000100000000000001"), ShortRead);
1244                 do_test!(concat!("03", "31", "043da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"), InvalidValue);
1245                 do_test!(concat!("03", "32", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001000000000000000001"), InvalidValue);
1246                 do_test!(concat!("fd00fe", "00"), ShortRead);
1247                 do_test!(concat!("fd00fe", "01", "01"), ShortRead);
1248                 do_test!(concat!("fd00fe", "03", "010101"), InvalidValue);
1249                 do_test!(concat!("00", "00"), UnknownRequiredFeature);
1250
1251                 do_test!(concat!("02", "08", "0000000000000226", "01", "01", "2a"), InvalidValue);
1252                 do_test!(concat!("02", "08", "0000000000000231", "02", "08", "0000000000000451"), InvalidValue);
1253                 do_test!(concat!("1f", "00", "0f", "01", "2a"), InvalidValue);
1254                 do_test!(concat!("1f", "00", "1f", "01", "2a"), InvalidValue);
1255
1256                 // The last BOLT test modified to not require creating a new decoder for one trivial test.
1257                 do_test!(concat!("ffffffffffffffffff", "00", "01", "00"), InvalidValue);
1258         }
1259
1260         #[test]
1261         fn bolt_tlv_valid_n1_stream() {
1262                 macro_rules! do_test {
1263                         ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
1264                                 if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
1265                                         assert_eq!(tlv1.map(|v| v.0), $tlv1);
1266                                         assert_eq!(tlv2, $tlv2);
1267                                         assert_eq!(tlv3, $tlv3);
1268                                         assert_eq!(tlv4, $tlv4);
1269                                 } else { panic!(); }
1270                         }
1271                 }
1272
1273                 do_test!(concat!(""), None, None, None, None);
1274                 do_test!(concat!("21", "00"), None, None, None, None);
1275                 do_test!(concat!("fd0201", "00"), None, None, None, None);
1276                 do_test!(concat!("fd00fd", "00"), None, None, None, None);
1277                 do_test!(concat!("fd00ff", "00"), None, None, None, None);
1278                 do_test!(concat!("fe02000001", "00"), None, None, None, None);
1279                 do_test!(concat!("ff0200000000000001", "00"), None, None, None, None);
1280
1281                 do_test!(concat!("01", "00"), Some(0), None, None, None);
1282                 do_test!(concat!("01", "01", "01"), Some(1), None, None, None);
1283                 do_test!(concat!("01", "02", "0100"), Some(256), None, None, None);
1284                 do_test!(concat!("01", "03", "010000"), Some(65536), None, None, None);
1285                 do_test!(concat!("01", "04", "01000000"), Some(16777216), None, None, None);
1286                 do_test!(concat!("01", "05", "0100000000"), Some(4294967296), None, None, None);
1287                 do_test!(concat!("01", "06", "010000000000"), Some(1099511627776), None, None, None);
1288                 do_test!(concat!("01", "07", "01000000000000"), Some(281474976710656), None, None, None);
1289                 do_test!(concat!("01", "08", "0100000000000000"), Some(72057594037927936), None, None, None);
1290                 do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
1291                 do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
1292                         None, None, Some((
1293                                 PublicKey::from_slice(&::hex::decode("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
1294                         None);
1295                 do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
1296         }
1297
1298         fn do_simple_test_tlv_write() -> Result<(), io::Error> {
1299                 let mut stream = VecWriter(Vec::new());
1300
1301                 stream.0.clear();
1302                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
1303                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
1304
1305                 stream.0.clear();
1306                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
1307                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
1308
1309                 stream.0.clear();
1310                 _encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
1311                 assert_eq!(stream.0, ::hex::decode("040402abcd").unwrap());
1312
1313                 stream.0.clear();
1314                 _encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
1315                 assert_eq!(stream.0, ::hex::decode("06fd00ff02abcd").unwrap());
1316
1317                 stream.0.clear();
1318                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1319                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
1320
1321                 stream.0.clear();
1322                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1323                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
1324
1325                 Ok(())
1326         }
1327
1328         #[test]
1329         fn simple_test_tlv_write() {
1330                 do_simple_test_tlv_write().unwrap();
1331         }
1332 }