git.bitcoin.ninja 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 // There are quite a few TLV serialization "types" which behave differently. We currently only
  17 // publicly document the `optional` and `required` types, not supporting anything else publicly and
  18 // changing them at will.
  19 //
  20 // Some of the other types include:
  21 //  * (default_value, $default) - reads optionally, reading $default if no TLV is present
  22 //  * (static_value, $value) - ignores any TLVs, always using $value
  23 //  * required_vec - reads into a Vec without a length prefix, failing if no TLV is present.
  24 //  * optional_vec - reads into an Option<Vec> without a length prefix, continuing if no TLV is
  25 //                   present. Writes from a Vec directly, only if any elements are present. Note
  26 //                   that the struct deserialization macros return a Vec, not an Option.
  27 //  * upgradable_option - reads via MaybeReadable.
  28 //  * upgradable_required - reads via MaybeReadable, requiring a TLV be present but may return None
  29 //                          if MaybeReadable::read() returns None.
  30
  31 /// Implements serialization for a single TLV record.
  32 /// This is exported for use by other exported macros, do not use directly.
  33 #[doc(hidden)]
  34 #[macro_export]
  35 macro_rules! _encode_tlv {
  36         ($stream: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
  37                 $crate::_encode_tlv!($stream, $type, $field, required)
  38         };
  39         ($stream: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
  40                 let _ = &$field; // Ensure we "use" the $field
  41         };
  42         ($stream: expr, $type: expr, $field: expr, required) => {
  43                 BigSize($type).write($stream)?;
  44                 BigSize($field.serialized_length() as u64).write($stream)?;
  45                 $field.write($stream)?;
  46         };
  47         ($stream: expr, $type: expr, $field: expr, required_vec) => {
  48                 $crate::_encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
  49         };
  50         ($stream: expr, $optional_type: expr, $optional_field: expr, option) => {
  51                 if let Some(ref field) = $optional_field {
  52                         BigSize($optional_type).write($stream)?;
  53                         BigSize(field.serialized_length() as u64).write($stream)?;
  54                         field.write($stream)?;
  55                 }
  56         };
  57         ($stream: expr, $type: expr, $field: expr, optional_vec) => {
  58                 if !$field.is_empty() {
  59                         $crate::_encode_tlv!($stream, $type, $field, required_vec);
  60                 }
  61         };
  62         ($stream: expr, $type: expr, $field: expr, upgradable_required) => {
  63                 $crate::_encode_tlv!($stream, $type, $field, required);
  64         };
  65         ($stream: expr, $type: expr, $field: expr, upgradable_option) => {
  66                 $crate::_encode_tlv!($stream, $type, $field, option);
  67         };
  68         ($stream: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
  69                 $crate::_encode_tlv!($stream, $type, $field.map(|f| $encoding(f)), option);
  70         };
  71         ($stream: expr, $type: expr, $field: expr, (option, encoding: $fieldty: ty)) => {
  72                 $crate::_encode_tlv!($stream, $type, $field, option);
  73         };
  74         ($stream: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
  75                 // Just a read-mapped type
  76                 $crate::_encode_tlv!($stream, $type, $field, option);
  77         };
  78 }
  79
  80 /// Panics if the last seen TLV type is not numerically less than the TLV type currently being checked.
  81 /// This is exported for use by other exported macros, do not use directly.
  82 #[doc(hidden)]
  83 #[macro_export]
  84 macro_rules! _check_encoded_tlv_order {
  85         ($last_type: expr, $type: expr, (static_value, $value: expr)) => { };
  86         ($last_type: expr, $type: expr, $fieldty: tt) => {
  87                 if let Some(t) = $last_type {
  88                         #[allow(unused_comparisons)] // Note that $type may be 0 making the following comparison always false
  89                         (debug_assert!(t < $type))
  90                 }
  91                 $last_type = Some($type);
  92         };
  93 }
  94
  95 /// Implements the TLVs serialization part in a [`Writeable`] implementation of a struct.
  96 ///
  97 /// This should be called inside a method which returns `Result<_, `[`io::Error`]`>`, such as
  98 /// [`Writeable::write`]. It will only return an `Err` if the stream `Err`s or [`Writeable::write`]
  99 /// on one of the fields `Err`s.
 100 ///
 101 /// `$stream` must be a `&mut `[`Writer`] which will receive the bytes for each TLV in the stream.
 102 ///
 103 /// Fields MUST be sorted in `$type`-order.
 104 ///
 105 /// Note that the lightning TLV requirements require that a single type not appear more than once,
 106 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
 107 /// decoder.
 108 ///
 109 /// Any `option` fields which have a value of `None` will not be serialized at all.
 110 ///
 111 /// For example,
 112 /// ```
 113 /// # use lightning::encode_tlv_stream;
 114 /// # fn write<W: lightning::util::ser::Writer> (stream: &mut W) -> Result<(), lightning::io::Error> {
 115 /// let mut required_value = 0u64;
 116 /// let mut optional_value: Option<u64> = None;
 117 /// encode_tlv_stream!(stream, {
 118 ///     (0, required_value, required),
 119 ///     (1, Some(42u64), option),
 120 ///     (2, optional_value, option),
 121 /// });
 122 /// // At this point `required_value` has been written as a TLV of type 0, `42u64` has been written
 123 /// // as a TLV of type 1 (indicating the reader may ignore it if it is not understood), and *no*
 124 /// // TLV is written with type 2.
 125 /// # Ok(())
 126 /// # }
 127 /// ```
 128 ///
 129 /// [`Writeable`]: crate::util::ser::Writeable
 130 /// [`io::Error`]: crate::io::Error
 131 /// [`Writeable::write`]: crate::util::ser::Writeable::write
 132 /// [`Writer`]: crate::util::ser::Writer
 133 #[macro_export]
 134 macro_rules! encode_tlv_stream {
 135         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
 136                 $crate::_encode_tlv_stream!($stream, {$(($type, $field, $fieldty)),*})
 137         }
 138 }
 139
 140 /// Implementation of [`encode_tlv_stream`].
 141 /// This is exported for use by other exported macros, do not use directly.
 142 #[doc(hidden)]
 143 #[macro_export]
 144 macro_rules! _encode_tlv_stream {
 145         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => { {
 146                 #[allow(unused_imports)]
 147                 use $crate::{
 148                         ln::msgs::DecodeError,
 149                         util::ser,
 150                         util::ser::BigSize,
 151                         util::ser::Writeable,
 152                 };
 153
 154                 $(
 155                         $crate::_encode_tlv!($stream, $type, $field, $fieldty);
 156                 )*
 157
 158                 #[allow(unused_mut, unused_variables, unused_assignments)]
 159                 #[cfg(debug_assertions)]
 160                 {
 161                         let mut last_seen: Option<u64> = None;
 162                         $(
 163                                 $crate::_check_encoded_tlv_order!(last_seen, $type, $fieldty);
 164                         )*
 165                 }
 166         } };
 167         ($stream: expr, $tlvs: expr) => { {
 168                 for tlv in $tlvs {
 169                         let (typ, value): &&(u64, Vec<u8>) = tlv;
 170                         $crate::_encode_tlv!($stream, *typ, *value, required_vec);
 171                 }
 172
 173                 #[cfg(debug_assertions)] {
 174                         let mut last_seen: Option<u64> = None;
 175                         for tlv in $tlvs {
 176                                 let (typ, _): &&(u64, Vec<u8>) = tlv;
 177                                 $crate::_check_encoded_tlv_order!(last_seen, *typ, required_vec);
 178                         }
 179                 }
 180         } };
 181 }
 182
 183 /// Adds the length of the serialized field to a [`LengthCalculatingWriter`].
 184 /// This is exported for use by other exported macros, do not use directly.
 185 ///
 186 /// [`LengthCalculatingWriter`]: crate::util::ser::LengthCalculatingWriter
 187 #[doc(hidden)]
 188 #[macro_export]
 189 macro_rules! _get_varint_length_prefixed_tlv_length {
 190         ($len: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
 191                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required)
 192         };
 193         ($len: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
 194         };
 195         ($len: expr, $type: expr, $field: expr, required) => {
 196                 BigSize($type).write(&mut $len).expect("No in-memory data may fail to serialize");
 197                 let field_len = $field.serialized_length();
 198                 BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
 199                 $len.0 += field_len;
 200         };
 201         ($len: expr, $type: expr, $field: expr, required_vec) => {
 202                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
 203         };
 204         ($len: expr, $optional_type: expr, $optional_field: expr, option) => {
 205                 if let Some(ref field) = $optional_field {
 206                         BigSize($optional_type).write(&mut $len).expect("No in-memory data may fail to serialize");
 207                         let field_len = field.serialized_length();
 208                         BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
 209                         $len.0 += field_len;
 210                 }
 211         };
 212         ($len: expr, $type: expr, $field: expr, optional_vec) => {
 213                 if !$field.is_empty() {
 214                         $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required_vec);
 215                 }
 216         };
 217         ($len: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
 218                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
 219         };
 220         ($len: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
 221                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field.map(|f| $encoding(f)), option);
 222         };
 223         ($len: expr, $type: expr, $field: expr, upgradable_required) => {
 224                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required);
 225         };
 226         ($len: expr, $type: expr, $field: expr, upgradable_option) => {
 227                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
 228         };
 229 }
 230
 231 /// See the documentation of [`write_tlv_fields`].
 232 /// This is exported for use by other exported macros, do not use directly.
 233 #[doc(hidden)]
 234 #[macro_export]
 235 macro_rules! _encode_varint_length_prefixed_tlv {
 236         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}) => { {
 237                 _encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*}, &[])
 238         } };
 239         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}, $extra_tlvs: expr) => { {
 240                 use $crate::util::ser::BigSize;
 241                 use alloc::vec::Vec;
 242                 let len = {
 243                         #[allow(unused_mut)]
 244                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 245                         $(
 246                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, $field, $fieldty);
 247                         )*
 248                         for tlv in $extra_tlvs {
 249                                 let (typ, value): &&(u64, Vec<u8>) = tlv;
 250                                 $crate::_get_varint_length_prefixed_tlv_length!(len, *typ, *value, required_vec);
 251                         }
 252                         len.0
 253                 };
 254                 BigSize(len as u64).write($stream)?;
 255                 $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* });
 256                 $crate::_encode_tlv_stream!($stream, $extra_tlvs);
 257         } };
 258 }
 259
 260 /// Errors if there are missing required TLV types between the last seen type and the type currently being processed.
 261 /// This is exported for use by other exported macros, do not use directly.
 262 #[doc(hidden)]
 263 #[macro_export]
 264 macro_rules! _check_decoded_tlv_order {
 265         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 266                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 267                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 268                 if invalid_order {
 269                         $field = $default.into();
 270                 }
 271         }};
 272         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (static_value, $value: expr)) => {
 273         };
 274         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required) => {{
 275                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 276                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 277                 if invalid_order {
 278                         return Err(DecodeError::InvalidValue);
 279                 }
 280         }};
 281         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 282                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
 283         }};
 284         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
 285                 // no-op
 286         }};
 287         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required_vec) => {{
 288                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
 289         }};
 290         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, optional_vec) => {{
 291                 // no-op
 292         }};
 293         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_required) => {{
 294                 _check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required)
 295         }};
 296         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_option) => {{
 297                 // no-op
 298         }};
 299         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 300                 // no-op
 301         }};
 302         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 303                 // no-op
 304         }};
 305 }
 306
 307 /// Errors if there are missing required TLV types after the last seen type.
 308 /// This is exported for use by other exported macros, do not use directly.
 309 #[doc(hidden)]
 310 #[macro_export]
 311 macro_rules! _check_missing_tlv {
 312         ($last_seen_type: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 313                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 314                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 315                 if missing_req_type {
 316                         $field = $default.into();
 317                 }
 318         }};
 319         ($last_seen_type: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
 320                 $field = $value;
 321         };
 322         ($last_seen_type: expr, $type: expr, $field: ident, required) => {{
 323                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 324                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 325                 if missing_req_type {
 326                         return Err(DecodeError::InvalidValue);
 327                 }
 328         }};
 329         ($last_seen_type: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 330                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 331         }};
 332         ($last_seen_type: expr, $type: expr, $field: ident, required_vec) => {{
 333                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 334         }};
 335         ($last_seen_type: expr, $type: expr, $field: ident, option) => {{
 336                 // no-op
 337         }};
 338         ($last_seen_type: expr, $type: expr, $field: ident, optional_vec) => {{
 339                 // no-op
 340         }};
 341         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_required) => {{
 342                 _check_missing_tlv!($last_seen_type, $type, $field, required)
 343         }};
 344         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_option) => {{
 345                 // no-op
 346         }};
 347         ($last_seen_type: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 348                 // no-op
 349         }};
 350         ($last_seen_type: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 351                 // no-op
 352         }};
 353 }
 354
 355 /// Implements deserialization for a single TLV record.
 356 /// This is exported for use by other exported macros, do not use directly.
 357 #[doc(hidden)]
 358 #[macro_export]
 359 macro_rules! _decode_tlv {
 360         ($reader: expr, $field: ident, (default_value, $default: expr)) => {{
 361                 $crate::_decode_tlv!($reader, $field, required)
 362         }};
 363         ($reader: expr, $field: ident, (static_value, $value: expr)) => {{
 364         }};
 365         ($reader: expr, $field: ident, required) => {{
 366                 $field = $crate::util::ser::Readable::read(&mut $reader)?;
 367         }};
 368         ($reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 369                 $field = $trait::read(&mut $reader $(, $read_arg)*)?;
 370         }};
 371         ($reader: expr, $field: ident, required_vec) => {{
 372                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 373                 $field = f.0;
 374         }};
 375         ($reader: expr, $field: ident, option) => {{
 376                 $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
 377         }};
 378         ($reader: expr, $field: ident, optional_vec) => {{
 379                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 380                 $field = Some(f.0);
 381         }};
 382         // `upgradable_required` indicates we're reading a required TLV that may have been upgraded
 383         // without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
 384         // field is present but we can no longer understand it.
 385         // Note that this variant can only be used within a `MaybeReadable` read.
 386         ($reader: expr, $field: ident, upgradable_required) => {{
 387                 $field = match $crate::util::ser::MaybeReadable::read(&mut $reader)? {
 388                         Some(res) => res,
 389                         _ => return Ok(None)
 390                 };
 391         }};
 392         // `upgradable_option` indicates we're reading an Option-al TLV that may have been upgraded
 393         // without backwards compat. $field will be None if the TLV is missing or if the field is present
 394         // but we can no longer understand it.
 395         ($reader: expr, $field: ident, upgradable_option) => {{
 396                 $field = $crate::util::ser::MaybeReadable::read(&mut $reader)?;
 397         }};
 398         ($reader: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 399                 $field = Some($trait::read(&mut $reader $(, $read_arg)*)?);
 400         }};
 401         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident, $encoder:ty))) => {{
 402                 $crate::_decode_tlv!($reader, $field, (option, encoding: ($fieldty, $encoding)));
 403         }};
 404         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {{
 405                 $field = {
 406                         let field: $encoding<$fieldty> = ser::Readable::read(&mut $reader)?;
 407                         Some(field.0)
 408                 };
 409         }};
 410         ($reader: expr, $field: ident, (option, encoding: $fieldty: ty)) => {{
 411                 $crate::_decode_tlv!($reader, $field, option);
 412         }};
 413 }
 414
 415 /// Checks if `$val` matches `$type`.
 416 /// This is exported for use by other exported macros, do not use directly.
 417 #[doc(hidden)]
 418 #[macro_export]
 419 macro_rules! _decode_tlv_stream_match_check {
 420         ($val: ident, $type: expr, (static_value, $value: expr)) => { false };
 421         ($val: ident, $type: expr, $fieldty: tt) => { $val == $type }
 422 }
 423
 424 /// Implements the TLVs deserialization part in a [`Readable`] implementation of a struct.
 425 ///
 426 /// This should be called inside a method which returns `Result<_, `[`DecodeError`]`>`, such as
 427 /// [`Readable::read`]. It will either return an `Err` or ensure all `required` fields have been
 428 /// read and optionally read `optional` fields.
 429 ///
 430 /// `$stream` must be a [`Read`] and will be fully consumed, reading until no more bytes remain
 431 /// (i.e. it returns [`DecodeError::ShortRead`]).
 432 ///
 433 /// Fields MUST be sorted in `$type`-order.
 434 ///
 435 /// Note that the lightning TLV requirements require that a single type not appear more than once,
 436 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
 437 /// decoder.
 438 ///
 439 /// For example,
 440 /// ```
 441 /// # use lightning::decode_tlv_stream;
 442 /// # fn read<R: lightning::io::Read> (stream: R) -> Result<(), lightning::ln::msgs::DecodeError> {
 443 /// let mut required_value = 0u64;
 444 /// let mut optional_value: Option<u64> = None;
 445 /// decode_tlv_stream!(stream, {
 446 ///     (0, required_value, required),
 447 ///     (2, optional_value, option),
 448 /// });
 449 /// // At this point, `required_value` has been overwritten with the TLV with type 0.
 450 /// // `optional_value` may have been overwritten, setting it to `Some` if a TLV with type 2 was
 451 /// // present.
 452 /// # Ok(())
 453 /// # }
 454 /// ```
 455 ///
 456 /// [`Readable`]: crate::util::ser::Readable
 457 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 458 /// [`Readable::read`]: crate::util::ser::Readable::read
 459 /// [`Read`]: crate::io::Read
 460 /// [`DecodeError::ShortRead`]: crate::ln::msgs::DecodeError::ShortRead
 461 #[macro_export]
 462 macro_rules! decode_tlv_stream {
 463         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 464                 let rewind = |_, _| { unreachable!() };
 465                 $crate::_decode_tlv_stream_range!($stream, .., rewind, {$(($type, $field, $fieldty)),*});
 466         }
 467 }
 468
 469 /// Similar to [`decode_tlv_stream`] with a custom TLV decoding capabilities.
 470 ///
 471 /// `$decode_custom_tlv` is a closure that may be optionally provided to handle custom message types.
 472 /// If it is provided, it will be called with the custom type and the [`FixedLengthReader`] containing
 473 /// the message contents. It should return `Ok(true)` if the custom message is successfully parsed,
 474 /// `Ok(false)` if the message type is unknown, and `Err(`[`DecodeError`]`)` if parsing fails.
 475 ///
 476 /// [`FixedLengthReader`]: crate::util::ser::FixedLengthReader
 477 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 478 macro_rules! decode_tlv_stream_with_custom_tlv_decode {
 479         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 480          $(, $decode_custom_tlv: expr)?) => { {
 481                 let rewind = |_, _| { unreachable!() };
 482                 _decode_tlv_stream_range!(
 483                         $stream, .., rewind, {$(($type, $field, $fieldty)),*} $(, $decode_custom_tlv)?
 484                 );
 485         } }
 486 }
 487
 488 #[doc(hidden)]
 489 #[macro_export]
 490 macro_rules! _decode_tlv_stream_range {
 491         ($stream: expr, $range: expr, $rewind: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 492          $(, $decode_custom_tlv: expr)?) => { {
 493                 use $crate::ln::msgs::DecodeError;
 494                 let mut last_seen_type: Option<u64> = None;
 495                 let mut stream_ref = $stream;
 496                 'tlv_read: loop {
 497                         use $crate::util::ser;
 498
 499                         // First decode the type of this TLV:
 500                         let typ: ser::BigSize = {
 501                                 // We track whether any bytes were read during the consensus_decode call to
 502                                 // determine whether we should break or return ShortRead if we get an
 503                                 // UnexpectedEof. This should in every case be largely cosmetic, but its nice to
 504                                 // pass the TLV test vectors exactly, which require this distinction.
 505                                 let mut tracking_reader = ser::ReadTrackingReader::new(&mut stream_ref);
 506                                 match <$crate::util::ser::BigSize as $crate::util::ser::Readable>::read(&mut tracking_reader) {
 507                                         Err(DecodeError::ShortRead) => {
 508                                                 if !tracking_reader.have_read {
 509                                                         break 'tlv_read;
 510                                                 } else {
 511                                                         return Err(DecodeError::ShortRead);
 512                                                 }
 513                                         },
 514                                         Err(e) => return Err(e),
 515                                         Ok(t) => if core::ops::RangeBounds::contains(&$range, &t.0) { t } else {
 516                                                 drop(tracking_reader);
 517
 518                                                 // Assumes the type id is minimally encoded, which is enforced on read.
 519                                                 use $crate::util::ser::Writeable;
 520                                                 let bytes_read = t.serialized_length();
 521                                                 $rewind(stream_ref, bytes_read);
 522                                                 break 'tlv_read;
 523                                         },
 524                                 }
 525                         };
 526
 527                         // Types must be unique and monotonically increasing:
 528                         match last_seen_type {
 529                                 Some(t) if typ.0 <= t => {
 530                                         return Err(DecodeError::InvalidValue);
 531                                 },
 532                                 _ => {},
 533                         }
 534                         // As we read types, make sure we hit every required type between `last_seen_type` and `typ`:
 535                         $({
 536                                 $crate::_check_decoded_tlv_order!(last_seen_type, typ, $type, $field, $fieldty);
 537                         })*
 538                         last_seen_type = Some(typ.0);
 539
 540                         // Finally, read the length and value itself:
 541                         let length: ser::BigSize = $crate::util::ser::Readable::read(&mut stream_ref)?;
 542                         let mut s = ser::FixedLengthReader::new(&mut stream_ref, length.0);
 543                         match typ.0 {
 544                                 $(_t if $crate::_decode_tlv_stream_match_check!(_t, $type, $fieldty) => {
 545                                         $crate::_decode_tlv!(s, $field, $fieldty);
 546                                         if s.bytes_remain() {
 547                                                 s.eat_remaining()?; // Return ShortRead if there's actually not enough bytes
 548                                                 return Err(DecodeError::InvalidValue);
 549                                         }
 550                                 },)*
 551                                 t => {
 552                                         $(
 553                                                 if $decode_custom_tlv(t, &mut s)? {
 554                                                         // If a custom TLV was successfully read (i.e. decode_custom_tlv returns true),
 555                                                         // continue to the next TLV read.
 556                                                         s.eat_remaining()?;
 557                                                         continue 'tlv_read;
 558                                                 }
 559                                         )?
 560                                         if t % 2 == 0 {
 561                                                 return Err(DecodeError::UnknownRequiredFeature);
 562                                         }
 563                                 }
 564                         }
 565                         s.eat_remaining()?;
 566                 }
 567                 // Make sure we got to each required type after we've read every TLV:
 568                 $({
 569                         $crate::_check_missing_tlv!(last_seen_type, $type, $field, $fieldty);
 570                 })*
 571         } }
 572 }
 573
 574 /// Implements [`Readable`]/[`Writeable`] for a message struct that may include non-TLV and
 575 /// TLV-encoded parts.
 576 ///
 577 /// This is useful to implement a [`CustomMessageReader`].
 578 ///
 579 /// Currently `$fieldty` may only be `option`, i.e., `$tlvfield` is optional field.
 580 ///
 581 /// For example,
 582 /// ```
 583 /// # use lightning::impl_writeable_msg;
 584 /// struct MyCustomMessage {
 585 ///     pub field_1: u32,
 586 ///     pub field_2: bool,
 587 ///     pub field_3: String,
 588 ///     pub tlv_optional_integer: Option<u32>,
 589 /// }
 590 ///
 591 /// impl_writeable_msg!(MyCustomMessage, {
 592 ///     field_1,
 593 ///     field_2,
 594 ///     field_3
 595 /// }, {
 596 ///     (1, tlv_optional_integer, option),
 597 /// });
 598 /// ```
 599 ///
 600 /// [`Readable`]: crate::util::ser::Readable
 601 /// [`Writeable`]: crate::util::ser::Writeable
 602 /// [`CustomMessageReader`]: crate::ln::wire::CustomMessageReader
 603 #[macro_export]
 604 macro_rules! impl_writeable_msg {
 605         ($st:ident, {$($field:ident),* $(,)*}, {$(($type: expr, $tlvfield: ident, $fieldty: tt)),* $(,)*}) => {
 606                 impl $crate::util::ser::Writeable for $st {
 607                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 608                                 $( self.$field.write(w)?; )*
 609                                 $crate::encode_tlv_stream!(w, {$(($type, self.$tlvfield.as_ref(), $fieldty)),*});
 610                                 Ok(())
 611                         }
 612                 }
 613                 impl $crate::util::ser::Readable for $st {
 614                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 615                                 $(let $field = $crate::util::ser::Readable::read(r)?;)*
 616                                 $($crate::_init_tlv_field_var!($tlvfield, $fieldty);)*
 617                                 $crate::decode_tlv_stream!(r, {$(($type, $tlvfield, $fieldty)),*});
 618                                 Ok(Self {
 619                                         $($field),*,
 620                                         $($tlvfield),*
 621                                 })
 622                         }
 623                 }
 624         }
 625 }
 626
 627 macro_rules! impl_writeable {
 628         ($st:ident, {$($field:ident),*}) => {
 629                 impl $crate::util::ser::Writeable for $st {
 630                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 631                                 $( self.$field.write(w)?; )*
 632                                 Ok(())
 633                         }
 634
 635                         #[inline]
 636                         fn serialized_length(&self) -> usize {
 637                                 let mut len_calc = 0;
 638                                 $( len_calc += self.$field.serialized_length(); )*
 639                                 return len_calc;
 640                         }
 641                 }
 642
 643                 impl $crate::util::ser::Readable for $st {
 644                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 645                                 Ok(Self {
 646                                         $($field: $crate::util::ser::Readable::read(r)?),*
 647                                 })
 648                         }
 649                 }
 650         }
 651 }
 652
 653 /// Write out two bytes to indicate the version of an object.
 654 ///
 655 /// $this_version represents a unique version of a type. Incremented whenever the type's
 656 /// serialization format has changed or has a new interpretation. Used by a type's reader to
 657 /// determine how to interpret fields or if it can understand a serialized object.
 658 ///
 659 /// $min_version_that_can_read_this is the minimum reader version which can understand this
 660 /// serialized object. Previous versions will simply err with a [`DecodeError::UnknownVersion`].
 661 ///
 662 /// Updates to either `$this_version` or `$min_version_that_can_read_this` should be included in
 663 /// release notes.
 664 ///
 665 /// Both version fields can be specific to this type of object.
 666 ///
 667 /// [`DecodeError::UnknownVersion`]: crate::ln::msgs::DecodeError::UnknownVersion
 668 macro_rules! write_ver_prefix {
 669         ($stream: expr, $this_version: expr, $min_version_that_can_read_this: expr) => {
 670                 $stream.write_all(&[$this_version; 1])?;
 671                 $stream.write_all(&[$min_version_that_can_read_this; 1])?;
 672         }
 673 }
 674
 675 /// Writes out a suffix to an object as a length-prefixed TLV stream which contains potentially
 676 /// backwards-compatible, optional fields which old nodes can happily ignore.
 677 ///
 678 /// It is written out in TLV format and, as with all TLV fields, unknown even fields cause a
 679 /// [`DecodeError::UnknownRequiredFeature`] error, with unknown odd fields ignored.
 680 ///
 681 /// This is the preferred method of adding new fields that old nodes can ignore and still function
 682 /// correctly.
 683 ///
 684 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
 685 #[macro_export]
 686 macro_rules! write_tlv_fields {
 687         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
 688                 $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*})
 689         }
 690 }
 691
 692 /// Reads a prefix added by [`write_ver_prefix`], above. Takes the current version of the
 693 /// serialization logic for this object. This is compared against the
 694 /// `$min_version_that_can_read_this` added by [`write_ver_prefix`].
 695 macro_rules! read_ver_prefix {
 696         ($stream: expr, $this_version: expr) => { {
 697                 let ver: u8 = Readable::read($stream)?;
 698                 let min_ver: u8 = Readable::read($stream)?;
 699                 if min_ver > $this_version {
 700                         return Err(DecodeError::UnknownVersion);
 701                 }
 702                 ver
 703         } }
 704 }
 705
 706 /// Reads a suffix added by [`write_tlv_fields`].
 707 ///
 708 /// [`write_tlv_fields`]: crate::write_tlv_fields
 709 #[macro_export]
 710 macro_rules! read_tlv_fields {
 711         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => { {
 712                 let tlv_len: $crate::util::ser::BigSize = $crate::util::ser::Readable::read($stream)?;
 713                 let mut rd = $crate::util::ser::FixedLengthReader::new($stream, tlv_len.0);
 714                 $crate::decode_tlv_stream!(&mut rd, {$(($type, $field, $fieldty)),*});
 715                 rd.eat_remaining().map_err(|_| $crate::ln::msgs::DecodeError::ShortRead)?;
 716         } }
 717 }
 718
 719 /// Initializes the struct fields.
 720 ///
 721 /// This is exported for use by other exported macros, do not use directly.
 722 #[doc(hidden)]
 723 #[macro_export]
 724 macro_rules! _init_tlv_based_struct_field {
 725         ($field: ident, (default_value, $default: expr)) => {
 726                 $field.0.unwrap()
 727         };
 728         ($field: ident, (static_value, $value: expr)) => {
 729                 $field
 730         };
 731         ($field: ident, option) => {
 732                 $field
 733         };
 734         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 735                 $crate::_init_tlv_based_struct_field!($field, option)
 736         };
 737         ($field: ident, upgradable_required) => {
 738                 $field.0.unwrap()
 739         };
 740         ($field: ident, upgradable_option) => {
 741                 $field
 742         };
 743         ($field: ident, required) => {
 744                 $field.0.unwrap()
 745         };
 746         ($field: ident, required_vec) => {
 747                 $field
 748         };
 749         ($field: ident, optional_vec) => {
 750                 $field.unwrap()
 751         };
 752 }
 753
 754 /// Initializes the variable we are going to read the TLV into.
 755 ///
 756 /// This is exported for use by other exported macros, do not use directly.
 757 #[doc(hidden)]
 758 #[macro_export]
 759 macro_rules! _init_tlv_field_var {
 760         ($field: ident, (default_value, $default: expr)) => {
 761                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 762         };
 763         ($field: ident, (static_value, $value: expr)) => {
 764                 let $field;
 765         };
 766         ($field: ident, required) => {
 767                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 768         };
 769         ($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
 770                 $crate::_init_tlv_field_var!($field, required);
 771         };
 772         ($field: ident, required_vec) => {
 773                 let mut $field = Vec::new();
 774         };
 775         ($field: ident, option) => {
 776                 let mut $field = None;
 777         };
 778         ($field: ident, optional_vec) => {
 779                 let mut $field = Some(Vec::new());
 780         };
 781         ($field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
 782                 $crate::_init_tlv_field_var!($field, option);
 783         };
 784         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 785                 $crate::_init_tlv_field_var!($field, option);
 786         };
 787         ($field: ident, upgradable_required) => {
 788                 let mut $field = $crate::util::ser::UpgradableRequired(None);
 789         };
 790         ($field: ident, upgradable_option) => {
 791                 let mut $field = None;
 792         };
 793 }
 794
 795 /// Equivalent to running [`_init_tlv_field_var`] then [`read_tlv_fields`].
 796 ///
 797 /// This is exported for use by other exported macros, do not use directly.
 798 #[doc(hidden)]
 799 #[macro_export]
 800 macro_rules! _init_and_read_tlv_fields {
 801         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 802                 $(
 803                         $crate::_init_tlv_field_var!($field, $fieldty);
 804                 )*
 805
 806                 $crate::read_tlv_fields!($reader, {
 807                         $(($type, $field, $fieldty)),*
 808                 });
 809         }
 810 }
 811
 812 /// Implements [`Readable`]/[`Writeable`] for a struct storing it as a set of TLVs
 813 /// If `$fieldty` is `required`, then `$field` is a required field that is not an [`Option`] nor a [`Vec`].
 814 /// If `$fieldty` is `(default_value, $default)`, then `$field` will be set to `$default` if not present.
 815 /// If `$fieldty` is `option`, then `$field` is optional field.
 816 /// If `$fieldty` is `optional_vec`, then `$field` is a [`Vec`], which needs to have its individual elements serialized.
 817 ///    Note that for `optional_vec` no bytes are written if the vec is empty
 818 ///
 819 /// For example,
 820 /// ```
 821 /// # use lightning::{impl_writeable_tlv_based, _encode_varint_length_prefixed_tlv};
 822 /// # extern crate alloc;
 823 /// struct LightningMessage {
 824 ///     tlv_integer: u32,
 825 ///     tlv_default_integer: u32,
 826 ///     tlv_optional_integer: Option<u32>,
 827 ///     tlv_vec_type_integer: Vec<u32>,
 828 /// }
 829 ///
 830 /// impl_writeable_tlv_based!(LightningMessage, {
 831 ///     (0, tlv_integer, required),
 832 ///     (1, tlv_default_integer, (default_value, 7)),
 833 ///     (2, tlv_optional_integer, option),
 834 ///     (3, tlv_vec_type_integer, optional_vec),
 835 /// });
 836 /// ```
 837 ///
 838 /// [`Readable`]: crate::util::ser::Readable
 839 /// [`Writeable`]: crate::util::ser::Writeable
 840 #[macro_export]
 841 macro_rules! impl_writeable_tlv_based {
 842         ($st: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 843                 impl $crate::util::ser::Writeable for $st {
 844                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 845                                 $crate::write_tlv_fields!(writer, {
 846                                         $(($type, self.$field, $fieldty)),*
 847                                 });
 848                                 Ok(())
 849                         }
 850
 851                         #[inline]
 852                         fn serialized_length(&self) -> usize {
 853                                 use $crate::util::ser::BigSize;
 854                                 let len = {
 855                                         #[allow(unused_mut)]
 856                                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 857                                         $(
 858                                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, self.$field, $fieldty);
 859                                         )*
 860                                         len.0
 861                                 };
 862                                 let mut len_calc = $crate::util::ser::LengthCalculatingWriter(0);
 863                                 BigSize(len as u64).write(&mut len_calc).expect("No in-memory data may fail to serialize");
 864                                 len + len_calc.0
 865                         }
 866                 }
 867
 868                 impl $crate::util::ser::Readable for $st {
 869                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 870                                 $crate::_init_and_read_tlv_fields!(reader, {
 871                                         $(($type, $field, $fieldty)),*
 872                                 });
 873                                 Ok(Self {
 874                                         $(
 875                                                 $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
 876                                         ),*
 877                                 })
 878                         }
 879                 }
 880         }
 881 }
 882
 883 /// Defines a struct for a TLV stream and a similar struct using references for non-primitive types,
 884 /// implementing [`Readable`] for the former and [`Writeable`] for the latter. Useful as an
 885 /// intermediary format when reading or writing a type encoded as a TLV stream. Note that each field
 886 /// representing a TLV record has its type wrapped with an [`Option`]. A tuple consisting of a type
 887 /// and a serialization wrapper may be given in place of a type when custom serialization is
 888 /// required.
 889 ///
 890 /// [`Readable`]: crate::util::ser::Readable
 891 /// [`Writeable`]: crate::util::ser::Writeable
 892 macro_rules! tlv_stream {
 893         ($name:ident, $nameref:ident, $range:expr, {
 894                 $(($type:expr, $field:ident : $fieldty:tt)),* $(,)*
 895         }) => {
 896                 #[derive(Debug)]
 897                 pub(super) struct $name {
 898                         $(
 899                                 pub(super) $field: Option<tlv_record_type!($fieldty)>,
 900                         )*
 901                 }
 902
 903                 #[cfg_attr(test, derive(PartialEq))]
 904                 #[derive(Debug)]
 905                 pub(super) struct $nameref<'a> {
 906                         $(
 907                                 pub(super) $field: Option<tlv_record_ref_type!($fieldty)>,
 908                         )*
 909                 }
 910
 911                 impl<'a> $crate::util::ser::Writeable for $nameref<'a> {
 912                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 913                                 encode_tlv_stream!(writer, {
 914                                         $(($type, self.$field, (option, encoding: $fieldty))),*
 915                                 });
 916                                 Ok(())
 917                         }
 918                 }
 919
 920                 impl $crate::util::ser::SeekReadable for $name {
 921                         fn read<R: $crate::io::Read + $crate::io::Seek>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 922                                 $(
 923                                         _init_tlv_field_var!($field, option);
 924                                 )*
 925                                 let rewind = |cursor: &mut R, offset: usize| {
 926                                         cursor.seek($crate::io::SeekFrom::Current(-(offset as i64))).expect("");
 927                                 };
 928                                 _decode_tlv_stream_range!(reader, $range, rewind, {
 929                                         $(($type, $field, (option, encoding: $fieldty))),*
 930                                 });
 931
 932                                 Ok(Self {
 933                                         $(
 934                                                 $field: $field
 935                                         ),*
 936                                 })
 937                         }
 938                 }
 939         }
 940 }
 941
 942 macro_rules! tlv_record_type {
 943         (($type:ty, $wrapper:ident)) => { $type };
 944         (($type:ty, $wrapper:ident, $encoder:ty)) => { $type };
 945         ($type:ty) => { $type };
 946 }
 947
 948 macro_rules! tlv_record_ref_type {
 949         (char) => { char };
 950         (u8) => { u8 };
 951         ((u16, $wrapper: ident)) => { u16 };
 952         ((u32, $wrapper: ident)) => { u32 };
 953         ((u64, $wrapper: ident)) => { u64 };
 954         (($type:ty, $wrapper:ident)) => { &'a $type };
 955         (($type:ty, $wrapper:ident, $encoder:ty)) => { $encoder };
 956         ($type:ty) => { &'a $type };
 957 }
 958
 959 #[doc(hidden)]
 960 #[macro_export]
 961 macro_rules! _impl_writeable_tlv_based_enum_common {
 962         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 963                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 964         ),* $(,)*;
 965         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
 966                 impl $crate::util::ser::Writeable for $st {
 967                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 968                                 match self {
 969                                         $($st::$variant_name { $(ref $field),* } => {
 970                                                 let id: u8 = $variant_id;
 971                                                 id.write(writer)?;
 972                                                 $crate::write_tlv_fields!(writer, {
 973                                                         $(($type, *$field, $fieldty)),*
 974                                                 });
 975                                         }),*
 976                                         $($st::$tuple_variant_name (ref field) => {
 977                                                 let id: u8 = $tuple_variant_id;
 978                                                 id.write(writer)?;
 979                                                 field.write(writer)?;
 980                                         }),*
 981                                 }
 982                                 Ok(())
 983                         }
 984                 }
 985         }
 986 }
 987
 988 /// Implement [`Readable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and tuple
 989 /// variants stored directly.
 990 /// The format is, for example
 991 /// ```ignore
 992 /// impl_writeable_tlv_based_enum!(EnumName,
 993 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
 994 ///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, optional_vec)};
 995 ///   (2, TupleVariantA), (3, TupleVariantB),
 996 /// );
 997 /// ```
 998 /// The type is written as a single byte, followed by any variant data.
 999 /// Attempts to read an unknown type byte result in [`DecodeError::UnknownRequiredFeature`].
1000 ///
1001 /// [`Readable`]: crate::util::ser::Readable
1002 /// [`Writeable`]: crate::util::ser::Writeable
1003 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1004 #[macro_export]
1005 macro_rules! impl_writeable_tlv_based_enum {
1006         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1007                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1008         ),* $(,)*;
1009         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
1010                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1011                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1012                         $(($tuple_variant_id, $tuple_variant_name)),*);
1013
1014                 impl $crate::util::ser::Readable for $st {
1015                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
1016                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1017                                 match id {
1018                                         $($variant_id => {
1019                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1020                                                 // in the same function body. Instead, we define a closure and call it.
1021                                                 let f = || {
1022                                                         $crate::_init_and_read_tlv_fields!(reader, {
1023                                                                 $(($type, $field, $fieldty)),*
1024                                                         });
1025                                                         Ok($st::$variant_name {
1026                                                                 $(
1027                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1028                                                                 ),*
1029                                                         })
1030                                                 };
1031                                                 f()
1032                                         }),*
1033                                         $($tuple_variant_id => {
1034                                                 Ok($st::$tuple_variant_name($crate::util::ser::Readable::read(reader)?))
1035                                         }),*
1036                                         _ => {
1037                                                 Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature)
1038                                         },
1039                                 }
1040                         }
1041                 }
1042         }
1043 }
1044
1045 /// Implement [`MaybeReadable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and
1046 /// tuple variants stored directly.
1047 ///
1048 /// This is largely identical to [`impl_writeable_tlv_based_enum`], except that odd variants will
1049 /// return `Ok(None)` instead of `Err(`[`DecodeError::UnknownRequiredFeature`]`)`. It should generally be preferred
1050 /// when [`MaybeReadable`] is practical instead of just [`Readable`] as it provides an upgrade path for
1051 /// new variants to be added which are simply ignored by existing clients.
1052 ///
1053 /// [`MaybeReadable`]: crate::util::ser::MaybeReadable
1054 /// [`Writeable`]: crate::util::ser::Writeable
1055 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1056 /// [`Readable`]: crate::util::ser::Readable
1057 #[macro_export]
1058 macro_rules! impl_writeable_tlv_based_enum_upgradable {
1059         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1060                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1061         ),* $(,)*
1062         $(;
1063         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
1064                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1065                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1066                         $($(($tuple_variant_id, $tuple_variant_name)),*)*);
1067
1068                 impl $crate::util::ser::MaybeReadable for $st {
1069                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Option<Self>, $crate::ln::msgs::DecodeError> {
1070                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1071                                 match id {
1072                                         $($variant_id => {
1073                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1074                                                 // in the same function body. Instead, we define a closure and call it.
1075                                                 let f = || {
1076                                                         $crate::_init_and_read_tlv_fields!(reader, {
1077                                                                 $(($type, $field, $fieldty)),*
1078                                                         });
1079                                                         Ok(Some($st::$variant_name {
1080                                                                 $(
1081                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1082                                                                 ),*
1083                                                         }))
1084                                                 };
1085                                                 f()
1086                                         }),*
1087                                         $($($tuple_variant_id => {
1088                                                 Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
1089                                         }),*)*
1090                                         _ if id % 2 == 1 => Ok(None),
1091                                         _ => Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature),
1092                                 }
1093                         }
1094                 }
1095         }
1096 }
1097
1098 #[cfg(test)]
1099 mod tests {
1100         use crate::io::{self, Cursor};
1101         use crate::prelude::*;
1102         use crate::ln::msgs::DecodeError;
1103         use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
1104         use bitcoin::secp256k1::PublicKey;
1105
1106         // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
1107         // the encoding layer in the BOLTs has no such concept, though it makes our macros easier to
1108         // work with so they're baked into the decoder. Thus, we have a few additional tests below
1109         fn tlv_reader(s: &[u8]) -> Result<(u64, u32, Option<u32>), DecodeError> {
1110                 let mut s = Cursor::new(s);
1111                 let mut a: u64 = 0;
1112                 let mut b: u32 = 0;
1113                 let mut c: Option<u32> = None;
1114                 decode_tlv_stream!(&mut s, {(2, a, required), (3, b, required), (4, c, option)});
1115                 Ok((a, b, c))
1116         }
1117
1118         #[test]
1119         fn tlv_v_short_read() {
1120                 // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
1121                 if let Err(DecodeError::ShortRead) = tlv_reader(&::hex::decode(
1122                                 concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
1123                                 ).unwrap()[..]) {
1124                 } else { panic!(); }
1125         }
1126
1127         #[test]
1128         fn tlv_types_out_of_order() {
1129                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1130                                 concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
1131                                 ).unwrap()[..]) {
1132                 } else { panic!(); }
1133                 // ...even if its some field we don't understand
1134                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1135                                 concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
1136                                 ).unwrap()[..]) {
1137                 } else { panic!(); }
1138         }
1139
1140         #[test]
1141         fn tlv_req_type_missing_or_extra() {
1142                 // It's also bad if they included even fields we don't understand
1143                 if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&::hex::decode(
1144                                 concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
1145                                 ).unwrap()[..]) {
1146                 } else { panic!(); }
1147                 // ... or if they're missing fields we need
1148                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1149                                 concat!("0100", "0208deadbeef1badbeef")
1150                                 ).unwrap()[..]) {
1151                 } else { panic!(); }
1152                 // ... even if that field is even
1153                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
1154                                 concat!("0304deadbeef", "0500")
1155                                 ).unwrap()[..]) {
1156                 } else { panic!(); }
1157         }
1158
1159         #[test]
1160         fn tlv_simple_good_cases() {
1161                 assert_eq!(tlv_reader(&::hex::decode(
1162                                 concat!("0208deadbeef1badbeef", "03041bad1dea")
1163                                 ).unwrap()[..]).unwrap(),
1164                         (0xdeadbeef1badbeef, 0x1bad1dea, None));
1165                 assert_eq!(tlv_reader(&::hex::decode(
1166                                 concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
1167                                 ).unwrap()[..]).unwrap(),
1168                         (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
1169         }
1170
1171         #[derive(Debug, PartialEq)]
1172         struct TestUpgradable {
1173                 a: u32,
1174                 b: u32,
1175                 c: Option<u32>,
1176         }
1177
1178         fn upgradable_tlv_reader(s: &[u8]) -> Result<Option<TestUpgradable>, DecodeError> {
1179                 let mut s = Cursor::new(s);
1180                 let mut a = 0;
1181                 let mut b = 0;
1182                 let mut c: Option<u32> = None;
1183                 decode_tlv_stream!(&mut s, {(2, a, upgradable_required), (3, b, upgradable_required), (4, c, upgradable_option)});
1184                 Ok(Some(TestUpgradable { a, b, c, }))
1185         }
1186
1187         #[test]
1188         fn upgradable_tlv_simple_good_cases() {
1189                 assert_eq!(upgradable_tlv_reader(&::hex::decode(
1190                         concat!("0204deadbeef", "03041bad1dea", "0404deadbeef")
1191                 ).unwrap()[..]).unwrap(),
1192                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: Some(0xdeadbeef) }));
1193
1194                 assert_eq!(upgradable_tlv_reader(&::hex::decode(
1195                         concat!("0204deadbeef", "03041bad1dea")
1196                 ).unwrap()[..]).unwrap(),
1197                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: None}));
1198         }
1199
1200         #[test]
1201         fn missing_required_upgradable() {
1202                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&::hex::decode(
1203                         concat!("0100", "0204deadbeef")
1204                         ).unwrap()[..]) {
1205                 } else { panic!(); }
1206                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&::hex::decode(
1207                         concat!("0100", "03041bad1dea")
1208                 ).unwrap()[..]) {
1209                 } else { panic!(); }
1210         }
1211
1212         // BOLT TLV test cases
1213         fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
1214                 let mut s = Cursor::new(s);
1215                 let mut tlv1: Option<HighZeroBytesDroppedBigSize<u64>> = None;
1216                 let mut tlv2: Option<u64> = None;
1217                 let mut tlv3: Option<(PublicKey, u64, u64)> = None;
1218                 let mut tlv4: Option<u16> = None;
1219                 decode_tlv_stream!(&mut s, {(1, tlv1, option), (2, tlv2, option), (3, tlv3, option), (254, tlv4, option)});
1220                 Ok((tlv1, tlv2, tlv3, tlv4))
1221         }
1222
1223         #[test]
1224         fn bolt_tlv_bogus_stream() {
1225                 macro_rules! do_test {
1226                         ($stream: expr, $reason: ident) => {
1227                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
1228                                 } else { panic!(); }
1229                         }
1230                 }
1231
1232                 // TLVs from the BOLT test cases which should not decode as either n1 or n2
1233                 do_test!(concat!("fd01"), ShortRead);
1234                 do_test!(concat!("fd0001", "00"), InvalidValue);
1235                 do_test!(concat!("fd0101"), ShortRead);
1236                 do_test!(concat!("0f", "fd"), ShortRead);
1237                 do_test!(concat!("0f", "fd26"), ShortRead);
1238                 do_test!(concat!("0f", "fd2602"), ShortRead);
1239                 do_test!(concat!("0f", "fd0001", "00"), InvalidValue);
1240                 do_test!(concat!("0f", "fd0201", "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"), ShortRead);
1241
1242                 do_test!(concat!("12", "00"), UnknownRequiredFeature);
1243                 do_test!(concat!("fd0102", "00"), UnknownRequiredFeature);
1244                 do_test!(concat!("fe01000002", "00"), UnknownRequiredFeature);
1245                 do_test!(concat!("ff0100000000000002", "00"), UnknownRequiredFeature);
1246         }
1247
1248         #[test]
1249         fn bolt_tlv_bogus_n1_stream() {
1250                 macro_rules! do_test {
1251                         ($stream: expr, $reason: ident) => {
1252                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
1253                                 } else { panic!(); }
1254                         }
1255                 }
1256
1257                 // TLVs from the BOLT test cases which should not decode as n1
1258                 do_test!(concat!("01", "09", "ffffffffffffffffff"), InvalidValue);
1259                 do_test!(concat!("01", "01", "00"), InvalidValue);
1260                 do_test!(concat!("01", "02", "0001"), InvalidValue);
1261                 do_test!(concat!("01", "03", "000100"), InvalidValue);
1262                 do_test!(concat!("01", "04", "00010000"), InvalidValue);
1263                 do_test!(concat!("01", "05", "0001000000"), InvalidValue);
1264                 do_test!(concat!("01", "06", "000100000000"), InvalidValue);
1265                 do_test!(concat!("01", "07", "00010000000000"), InvalidValue);
1266                 do_test!(concat!("01", "08", "0001000000000000"), InvalidValue);
1267                 do_test!(concat!("02", "07", "01010101010101"), ShortRead);
1268                 do_test!(concat!("02", "09", "010101010101010101"), InvalidValue);
1269                 do_test!(concat!("03", "21", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb"), ShortRead);
1270                 do_test!(concat!("03", "29", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001"), ShortRead);
1271                 do_test!(concat!("03", "30", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb000000000000000100000000000001"), ShortRead);
1272                 do_test!(concat!("03", "31", "043da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"), InvalidValue);
1273                 do_test!(concat!("03", "32", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001000000000000000001"), InvalidValue);
1274                 do_test!(concat!("fd00fe", "00"), ShortRead);
1275                 do_test!(concat!("fd00fe", "01", "01"), ShortRead);
1276                 do_test!(concat!("fd00fe", "03", "010101"), InvalidValue);
1277                 do_test!(concat!("00", "00"), UnknownRequiredFeature);
1278
1279                 do_test!(concat!("02", "08", "0000000000000226", "01", "01", "2a"), InvalidValue);
1280                 do_test!(concat!("02", "08", "0000000000000231", "02", "08", "0000000000000451"), InvalidValue);
1281                 do_test!(concat!("1f", "00", "0f", "01", "2a"), InvalidValue);
1282                 do_test!(concat!("1f", "00", "1f", "01", "2a"), InvalidValue);
1283
1284                 // The last BOLT test modified to not require creating a new decoder for one trivial test.
1285                 do_test!(concat!("ffffffffffffffffff", "00", "01", "00"), InvalidValue);
1286         }
1287
1288         #[test]
1289         fn bolt_tlv_valid_n1_stream() {
1290                 macro_rules! do_test {
1291                         ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
1292                                 if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
1293                                         assert_eq!(tlv1.map(|v| v.0), $tlv1);
1294                                         assert_eq!(tlv2, $tlv2);
1295                                         assert_eq!(tlv3, $tlv3);
1296                                         assert_eq!(tlv4, $tlv4);
1297                                 } else { panic!(); }
1298                         }
1299                 }
1300
1301                 do_test!(concat!(""), None, None, None, None);
1302                 do_test!(concat!("21", "00"), None, None, None, None);
1303                 do_test!(concat!("fd0201", "00"), None, None, None, None);
1304                 do_test!(concat!("fd00fd", "00"), None, None, None, None);
1305                 do_test!(concat!("fd00ff", "00"), None, None, None, None);
1306                 do_test!(concat!("fe02000001", "00"), None, None, None, None);
1307                 do_test!(concat!("ff0200000000000001", "00"), None, None, None, None);
1308
1309                 do_test!(concat!("01", "00"), Some(0), None, None, None);
1310                 do_test!(concat!("01", "01", "01"), Some(1), None, None, None);
1311                 do_test!(concat!("01", "02", "0100"), Some(256), None, None, None);
1312                 do_test!(concat!("01", "03", "010000"), Some(65536), None, None, None);
1313                 do_test!(concat!("01", "04", "01000000"), Some(16777216), None, None, None);
1314                 do_test!(concat!("01", "05", "0100000000"), Some(4294967296), None, None, None);
1315                 do_test!(concat!("01", "06", "010000000000"), Some(1099511627776), None, None, None);
1316                 do_test!(concat!("01", "07", "01000000000000"), Some(281474976710656), None, None, None);
1317                 do_test!(concat!("01", "08", "0100000000000000"), Some(72057594037927936), None, None, None);
1318                 do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
1319                 do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
1320                         None, None, Some((
1321                                 PublicKey::from_slice(&::hex::decode("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
1322                         None);
1323                 do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
1324         }
1325
1326         fn do_simple_test_tlv_write() -> Result<(), io::Error> {
1327                 let mut stream = VecWriter(Vec::new());
1328
1329                 stream.0.clear();
1330                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
1331                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
1332
1333                 stream.0.clear();
1334                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
1335                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
1336
1337                 stream.0.clear();
1338                 _encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
1339                 assert_eq!(stream.0, ::hex::decode("040402abcd").unwrap());
1340
1341                 stream.0.clear();
1342                 _encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
1343                 assert_eq!(stream.0, ::hex::decode("06fd00ff02abcd").unwrap());
1344
1345                 stream.0.clear();
1346                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1347                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
1348
1349                 stream.0.clear();
1350                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1351                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
1352
1353                 Ok(())
1354         }
1355
1356         #[test]
1357         fn simple_test_tlv_write() {
1358                 do_simple_test_tlv_write().unwrap();
1359         }
1360 }