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