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