_ 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                 $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, &[])
 147         } };
 148         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}, $extra_tlvs: expr) => { {
 149                 #[allow(unused_imports)]
 150                 use $crate::{
 151                         ln::msgs::DecodeError,
 152                         util::ser,
 153                         util::ser::BigSize,
 154                         util::ser::Writeable,
 155                 };
 156
 157                 $(
 158                         $crate::_encode_tlv!($stream, $type, $field, $fieldty);
 159                 )*
 160                 for tlv in $extra_tlvs {
 161                         let (typ, value): &(u64, Vec<u8>) = tlv;
 162                         $crate::_encode_tlv!($stream, *typ, *value, required_vec);
 163                 }
 164
 165                 #[allow(unused_mut, unused_variables, unused_assignments)]
 166                 #[cfg(debug_assertions)]
 167                 {
 168                         let mut last_seen: Option<u64> = None;
 169                         $(
 170                                 $crate::_check_encoded_tlv_order!(last_seen, $type, $fieldty);
 171                         )*
 172                         for tlv in $extra_tlvs {
 173                                 let (typ, _): &(u64, Vec<u8>) = tlv;
 174                                 $crate::_check_encoded_tlv_order!(last_seen, *typ, required_vec);
 175                         }
 176                 }
 177         } };
 178 }
 179
 180 /// Adds the length of the serialized field to a [`LengthCalculatingWriter`].
 181 /// This is exported for use by other exported macros, do not use directly.
 182 ///
 183 /// [`LengthCalculatingWriter`]: crate::util::ser::LengthCalculatingWriter
 184 #[doc(hidden)]
 185 #[macro_export]
 186 macro_rules! _get_varint_length_prefixed_tlv_length {
 187         ($len: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
 188                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required)
 189         };
 190         ($len: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
 191         };
 192         ($len: expr, $type: expr, $field: expr, required) => {
 193                 BigSize($type).write(&mut $len).expect("No in-memory data may fail to serialize");
 194                 let field_len = $field.serialized_length();
 195                 BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
 196                 $len.0 += field_len;
 197         };
 198         ($len: expr, $type: expr, $field: expr, required_vec) => {
 199                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
 200         };
 201         ($len: expr, $optional_type: expr, $optional_field: expr, option) => {
 202                 if let Some(ref field) = $optional_field {
 203                         BigSize($optional_type).write(&mut $len).expect("No in-memory data may fail to serialize");
 204                         let field_len = field.serialized_length();
 205                         BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
 206                         $len.0 += field_len;
 207                 }
 208         };
 209         ($len: expr, $type: expr, $field: expr, optional_vec) => {
 210                 if !$field.is_empty() {
 211                         $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required_vec);
 212                 }
 213         };
 214         ($len: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
 215                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
 216         };
 217         ($len: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
 218                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field.map(|f| $encoding(f)), option);
 219         };
 220         ($len: expr, $type: expr, $field: expr, upgradable_required) => {
 221                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required);
 222         };
 223         ($len: expr, $type: expr, $field: expr, upgradable_option) => {
 224                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
 225         };
 226 }
 227
 228 /// See the documentation of [`write_tlv_fields`].
 229 /// This is exported for use by other exported macros, do not use directly.
 230 #[doc(hidden)]
 231 #[macro_export]
 232 macro_rules! _encode_varint_length_prefixed_tlv {
 233         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}) => { {
 234                 $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*}, &[])
 235         } };
 236         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}, $extra_tlvs: expr) => { {
 237                 extern crate alloc;
 238                 use $crate::util::ser::BigSize;
 239                 use alloc::vec::Vec;
 240                 let len = {
 241                         #[allow(unused_mut)]
 242                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 243                         $(
 244                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, $field, $fieldty);
 245                         )*
 246                         for tlv in $extra_tlvs {
 247                                 let (typ, value): &(u64, Vec<u8>) = tlv;
 248                                 $crate::_get_varint_length_prefixed_tlv_length!(len, *typ, *value, required_vec);
 249                         }
 250                         len.0
 251                 };
 252                 BigSize(len as u64).write($stream)?;
 253                 $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, $extra_tlvs);
 254         } };
 255 }
 256
 257 /// Errors if there are missing required TLV types between the last seen type and the type currently being processed.
 258 /// This is exported for use by other exported macros, do not use directly.
 259 #[doc(hidden)]
 260 #[macro_export]
 261 macro_rules! _check_decoded_tlv_order {
 262         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 263                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 264                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 265                 if invalid_order {
 266                         $field = $default.into();
 267                 }
 268         }};
 269         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (static_value, $value: expr)) => {
 270         };
 271         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required) => {{
 272                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 273                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 274                 if invalid_order {
 275                         return Err(DecodeError::InvalidValue);
 276                 }
 277         }};
 278         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 279                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
 280         }};
 281         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
 282                 // no-op
 283         }};
 284         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required_vec) => {{
 285                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
 286         }};
 287         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, optional_vec) => {{
 288                 // no-op
 289         }};
 290         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_required) => {{
 291                 _check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required)
 292         }};
 293         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_option) => {{
 294                 // no-op
 295         }};
 296         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 297                 // no-op
 298         }};
 299         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 300                 // no-op
 301         }};
 302 }
 303
 304 /// Errors if there are missing required TLV types after the last seen type.
 305 /// This is exported for use by other exported macros, do not use directly.
 306 #[doc(hidden)]
 307 #[macro_export]
 308 macro_rules! _check_missing_tlv {
 309         ($last_seen_type: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 310                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 311                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 312                 if missing_req_type {
 313                         $field = $default.into();
 314                 }
 315         }};
 316         ($last_seen_type: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
 317                 $field = $value;
 318         };
 319         ($last_seen_type: expr, $type: expr, $field: ident, required) => {{
 320                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
 321                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 322                 if missing_req_type {
 323                         return Err(DecodeError::InvalidValue);
 324                 }
 325         }};
 326         ($last_seen_type: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 327                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 328         }};
 329         ($last_seen_type: expr, $type: expr, $field: ident, required_vec) => {{
 330                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 331         }};
 332         ($last_seen_type: expr, $type: expr, $field: ident, option) => {{
 333                 // no-op
 334         }};
 335         ($last_seen_type: expr, $type: expr, $field: ident, optional_vec) => {{
 336                 // no-op
 337         }};
 338         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_required) => {{
 339                 _check_missing_tlv!($last_seen_type, $type, $field, required)
 340         }};
 341         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_option) => {{
 342                 // no-op
 343         }};
 344         ($last_seen_type: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 345                 // no-op
 346         }};
 347         ($last_seen_type: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 348                 // no-op
 349         }};
 350 }
 351
 352 /// Implements deserialization for a single TLV record.
 353 /// This is exported for use by other exported macros, do not use directly.
 354 #[doc(hidden)]
 355 #[macro_export]
 356 macro_rules! _decode_tlv {
 357         ($reader: expr, $field: ident, (default_value, $default: expr)) => {{
 358                 $crate::_decode_tlv!($reader, $field, required)
 359         }};
 360         ($reader: expr, $field: ident, (static_value, $value: expr)) => {{
 361         }};
 362         ($reader: expr, $field: ident, required) => {{
 363                 $field = $crate::util::ser::Readable::read(&mut $reader)?;
 364         }};
 365         ($reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 366                 $field = $trait::read(&mut $reader $(, $read_arg)*)?;
 367         }};
 368         ($reader: expr, $field: ident, required_vec) => {{
 369                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 370                 $field = f.0;
 371         }};
 372         ($reader: expr, $field: ident, option) => {{
 373                 $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
 374         }};
 375         ($reader: expr, $field: ident, optional_vec) => {{
 376                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 377                 $field = Some(f.0);
 378         }};
 379         // `upgradable_required` indicates we're reading a required TLV that may have been upgraded
 380         // without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
 381         // field is present but we can no longer understand it.
 382         // Note that this variant can only be used within a `MaybeReadable` read.
 383         ($reader: expr, $field: ident, upgradable_required) => {{
 384                 $field = match $crate::util::ser::MaybeReadable::read(&mut $reader)? {
 385                         Some(res) => res,
 386                         _ => return Ok(None)
 387                 };
 388         }};
 389         // `upgradable_option` indicates we're reading an Option-al TLV that may have been upgraded
 390         // without backwards compat. $field will be None if the TLV is missing or if the field is present
 391         // but we can no longer understand it.
 392         ($reader: expr, $field: ident, upgradable_option) => {{
 393                 $field = $crate::util::ser::MaybeReadable::read(&mut $reader)?;
 394         }};
 395         ($reader: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 396                 $field = Some($trait::read(&mut $reader $(, $read_arg)*)?);
 397         }};
 398         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident, $encoder:ty))) => {{
 399                 $crate::_decode_tlv!($reader, $field, (option, encoding: ($fieldty, $encoding)));
 400         }};
 401         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {{
 402                 $field = {
 403                         let field: $encoding<$fieldty> = ser::Readable::read(&mut $reader)?;
 404                         Some(field.0)
 405                 };
 406         }};
 407         ($reader: expr, $field: ident, (option, encoding: $fieldty: ty)) => {{
 408                 $crate::_decode_tlv!($reader, $field, option);
 409         }};
 410 }
 411
 412 /// Checks if `$val` matches `$type`.
 413 /// This is exported for use by other exported macros, do not use directly.
 414 #[doc(hidden)]
 415 #[macro_export]
 416 macro_rules! _decode_tlv_stream_match_check {
 417         ($val: ident, $type: expr, (static_value, $value: expr)) => { false };
 418         ($val: ident, $type: expr, $fieldty: tt) => { $val == $type }
 419 }
 420
 421 /// Implements the TLVs deserialization part in a [`Readable`] implementation of a struct.
 422 ///
 423 /// This should be called inside a method which returns `Result<_, `[`DecodeError`]`>`, such as
 424 /// [`Readable::read`]. It will either return an `Err` or ensure all `required` fields have been
 425 /// read and optionally read `optional` fields.
 426 ///
 427 /// `$stream` must be a [`Read`] and will be fully consumed, reading until no more bytes remain
 428 /// (i.e. it returns [`DecodeError::ShortRead`]).
 429 ///
 430 /// Fields MUST be sorted in `$type`-order.
 431 ///
 432 /// Note that the lightning TLV requirements require that a single type not appear more than once,
 433 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
 434 /// decoder.
 435 ///
 436 /// For example,
 437 /// ```
 438 /// # use lightning::decode_tlv_stream;
 439 /// # fn read<R: lightning::io::Read> (stream: R) -> Result<(), lightning::ln::msgs::DecodeError> {
 440 /// let mut required_value = 0u64;
 441 /// let mut optional_value: Option<u64> = None;
 442 /// decode_tlv_stream!(stream, {
 443 ///     (0, required_value, required),
 444 ///     (2, optional_value, option),
 445 /// });
 446 /// // At this point, `required_value` has been overwritten with the TLV with type 0.
 447 /// // `optional_value` may have been overwritten, setting it to `Some` if a TLV with type 2 was
 448 /// // present.
 449 /// # Ok(())
 450 /// # }
 451 /// ```
 452 ///
 453 /// [`Readable`]: crate::util::ser::Readable
 454 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 455 /// [`Readable::read`]: crate::util::ser::Readable::read
 456 /// [`Read`]: crate::io::Read
 457 /// [`DecodeError::ShortRead`]: crate::ln::msgs::DecodeError::ShortRead
 458 #[macro_export]
 459 macro_rules! decode_tlv_stream {
 460         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 461                 let rewind = |_, _| { unreachable!() };
 462                 $crate::_decode_tlv_stream_range!($stream, .., rewind, {$(($type, $field, $fieldty)),*});
 463         }
 464 }
 465
 466 /// Similar to [`decode_tlv_stream`] with a custom TLV decoding capabilities.
 467 ///
 468 /// `$decode_custom_tlv` is a closure that may be optionally provided to handle custom message types.
 469 /// If it is provided, it will be called with the custom type and the [`FixedLengthReader`] containing
 470 /// the message contents. It should return `Ok(true)` if the custom message is successfully parsed,
 471 /// `Ok(false)` if the message type is unknown, and `Err(`[`DecodeError`]`)` if parsing fails.
 472 ///
 473 /// [`FixedLengthReader`]: crate::util::ser::FixedLengthReader
 474 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 475 macro_rules! decode_tlv_stream_with_custom_tlv_decode {
 476         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 477          $(, $decode_custom_tlv: expr)?) => { {
 478                 let rewind = |_, _| { unreachable!() };
 479                 _decode_tlv_stream_range!(
 480                         $stream, .., rewind, {$(($type, $field, $fieldty)),*} $(, $decode_custom_tlv)?
 481                 );
 482         } }
 483 }
 484
 485 #[doc(hidden)]
 486 #[macro_export]
 487 macro_rules! _decode_tlv_stream_range {
 488         ($stream: expr, $range: expr, $rewind: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 489          $(, $decode_custom_tlv: expr)?) => { {
 490                 use $crate::ln::msgs::DecodeError;
 491                 let mut last_seen_type: Option<u64> = None;
 492                 let mut stream_ref = $stream;
 493                 'tlv_read: loop {
 494                         use $crate::util::ser;
 495
 496                         // First decode the type of this TLV:
 497                         let typ: ser::BigSize = {
 498                                 // We track whether any bytes were read during the consensus_decode call to
 499                                 // determine whether we should break or return ShortRead if we get an
 500                                 // UnexpectedEof. This should in every case be largely cosmetic, but its nice to
 501                                 // pass the TLV test vectors exactly, which require this distinction.
 502                                 let mut tracking_reader = ser::ReadTrackingReader::new(&mut stream_ref);
 503                                 match <$crate::util::ser::BigSize as $crate::util::ser::Readable>::read(&mut tracking_reader) {
 504                                         Err(DecodeError::ShortRead) => {
 505                                                 if !tracking_reader.have_read {
 506                                                         break 'tlv_read;
 507                                                 } else {
 508                                                         return Err(DecodeError::ShortRead);
 509                                                 }
 510                                         },
 511                                         Err(e) => return Err(e),
 512                                         Ok(t) => if core::ops::RangeBounds::contains(&$range, &t.0) { t } else {
 513                                                 drop(tracking_reader);
 514
 515                                                 // Assumes the type id is minimally encoded, which is enforced on read.
 516                                                 use $crate::util::ser::Writeable;
 517                                                 let bytes_read = t.serialized_length();
 518                                                 $rewind(stream_ref, bytes_read);
 519                                                 break 'tlv_read;
 520                                         },
 521                                 }
 522                         };
 523
 524                         // Types must be unique and monotonically increasing:
 525                         match last_seen_type {
 526                                 Some(t) if typ.0 <= t => {
 527                                         return Err(DecodeError::InvalidValue);
 528                                 },
 529                                 _ => {},
 530                         }
 531                         // As we read types, make sure we hit every required type between `last_seen_type` and `typ`:
 532                         $({
 533                                 $crate::_check_decoded_tlv_order!(last_seen_type, typ, $type, $field, $fieldty);
 534                         })*
 535                         last_seen_type = Some(typ.0);
 536
 537                         // Finally, read the length and value itself:
 538                         let length: ser::BigSize = $crate::util::ser::Readable::read(&mut stream_ref)?;
 539                         let mut s = ser::FixedLengthReader::new(&mut stream_ref, length.0);
 540                         match typ.0 {
 541                                 $(_t if $crate::_decode_tlv_stream_match_check!(_t, $type, $fieldty) => {
 542                                         $crate::_decode_tlv!(s, $field, $fieldty);
 543                                         if s.bytes_remain() {
 544                                                 s.eat_remaining()?; // Return ShortRead if there's actually not enough bytes
 545                                                 return Err(DecodeError::InvalidValue);
 546                                         }
 547                                 },)*
 548                                 t => {
 549                                         $(
 550                                                 if $decode_custom_tlv(t, &mut s)? {
 551                                                         // If a custom TLV was successfully read (i.e. decode_custom_tlv returns true),
 552                                                         // continue to the next TLV read.
 553                                                         s.eat_remaining()?;
 554                                                         continue 'tlv_read;
 555                                                 }
 556                                         )?
 557                                         if t % 2 == 0 {
 558                                                 return Err(DecodeError::UnknownRequiredFeature);
 559                                         }
 560                                 }
 561                         }
 562                         s.eat_remaining()?;
 563                 }
 564                 // Make sure we got to each required type after we've read every TLV:
 565                 $({
 566                         $crate::_check_missing_tlv!(last_seen_type, $type, $field, $fieldty);
 567                 })*
 568         } }
 569 }
 570
 571 /// Implements [`Readable`]/[`Writeable`] for a message struct that may include non-TLV and
 572 /// TLV-encoded parts.
 573 ///
 574 /// This is useful to implement a [`CustomMessageReader`].
 575 ///
 576 /// Currently `$fieldty` may only be `option`, i.e., `$tlvfield` is optional field.
 577 ///
 578 /// For example,
 579 /// ```
 580 /// # use lightning::impl_writeable_msg;
 581 /// struct MyCustomMessage {
 582 ///     pub field_1: u32,
 583 ///     pub field_2: bool,
 584 ///     pub field_3: String,
 585 ///     pub tlv_optional_integer: Option<u32>,
 586 /// }
 587 ///
 588 /// impl_writeable_msg!(MyCustomMessage, {
 589 ///     field_1,
 590 ///     field_2,
 591 ///     field_3
 592 /// }, {
 593 ///     (1, tlv_optional_integer, option),
 594 /// });
 595 /// ```
 596 ///
 597 /// [`Readable`]: crate::util::ser::Readable
 598 /// [`Writeable`]: crate::util::ser::Writeable
 599 /// [`CustomMessageReader`]: crate::ln::wire::CustomMessageReader
 600 #[macro_export]
 601 macro_rules! impl_writeable_msg {
 602         ($st:ident, {$($field:ident),* $(,)*}, {$(($type: expr, $tlvfield: ident, $fieldty: tt)),* $(,)*}) => {
 603                 impl $crate::util::ser::Writeable for $st {
 604                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 605                                 $( self.$field.write(w)?; )*
 606                                 $crate::encode_tlv_stream!(w, {$(($type, self.$tlvfield.as_ref(), $fieldty)),*});
 607                                 Ok(())
 608                         }
 609                 }
 610                 impl $crate::util::ser::Readable for $st {
 611                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 612                                 $(let $field = $crate::util::ser::Readable::read(r)?;)*
 613                                 $($crate::_init_tlv_field_var!($tlvfield, $fieldty);)*
 614                                 $crate::decode_tlv_stream!(r, {$(($type, $tlvfield, $fieldty)),*});
 615                                 Ok(Self {
 616                                         $($field),*,
 617                                         $($tlvfield),*
 618                                 })
 619                         }
 620                 }
 621         }
 622 }
 623
 624 macro_rules! impl_writeable {
 625         ($st:ident, {$($field:ident),*}) => {
 626                 impl $crate::util::ser::Writeable for $st {
 627                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 628                                 $( self.$field.write(w)?; )*
 629                                 Ok(())
 630                         }
 631
 632                         #[inline]
 633                         fn serialized_length(&self) -> usize {
 634                                 let mut len_calc = 0;
 635                                 $( len_calc += self.$field.serialized_length(); )*
 636                                 return len_calc;
 637                         }
 638                 }
 639
 640                 impl $crate::util::ser::Readable for $st {
 641                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 642                                 Ok(Self {
 643                                         $($field: $crate::util::ser::Readable::read(r)?),*
 644                                 })
 645                         }
 646                 }
 647         }
 648 }
 649
 650 /// Write out two bytes to indicate the version of an object.
 651 ///
 652 /// $this_version represents a unique version of a type. Incremented whenever the type's
 653 /// serialization format has changed or has a new interpretation. Used by a type's reader to
 654 /// determine how to interpret fields or if it can understand a serialized object.
 655 ///
 656 /// $min_version_that_can_read_this is the minimum reader version which can understand this
 657 /// serialized object. Previous versions will simply err with a [`DecodeError::UnknownVersion`].
 658 ///
 659 /// Updates to either `$this_version` or `$min_version_that_can_read_this` should be included in
 660 /// release notes.
 661 ///
 662 /// Both version fields can be specific to this type of object.
 663 ///
 664 /// [`DecodeError::UnknownVersion`]: crate::ln::msgs::DecodeError::UnknownVersion
 665 macro_rules! write_ver_prefix {
 666         ($stream: expr, $this_version: expr, $min_version_that_can_read_this: expr) => {
 667                 $stream.write_all(&[$this_version; 1])?;
 668                 $stream.write_all(&[$min_version_that_can_read_this; 1])?;
 669         }
 670 }
 671
 672 /// Writes out a suffix to an object as a length-prefixed TLV stream which contains potentially
 673 /// backwards-compatible, optional fields which old nodes can happily ignore.
 674 ///
 675 /// It is written out in TLV format and, as with all TLV fields, unknown even fields cause a
 676 /// [`DecodeError::UnknownRequiredFeature`] error, with unknown odd fields ignored.
 677 ///
 678 /// This is the preferred method of adding new fields that old nodes can ignore and still function
 679 /// correctly.
 680 ///
 681 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
 682 #[macro_export]
 683 macro_rules! write_tlv_fields {
 684         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
 685                 $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*})
 686         }
 687 }
 688
 689 /// Reads a prefix added by [`write_ver_prefix`], above. Takes the current version of the
 690 /// serialization logic for this object. This is compared against the
 691 /// `$min_version_that_can_read_this` added by [`write_ver_prefix`].
 692 macro_rules! read_ver_prefix {
 693         ($stream: expr, $this_version: expr) => { {
 694                 let ver: u8 = Readable::read($stream)?;
 695                 let min_ver: u8 = Readable::read($stream)?;
 696                 if min_ver > $this_version {
 697                         return Err(DecodeError::UnknownVersion);
 698                 }
 699                 ver
 700         } }
 701 }
 702
 703 /// Reads a suffix added by [`write_tlv_fields`].
 704 ///
 705 /// [`write_tlv_fields`]: crate::write_tlv_fields
 706 #[macro_export]
 707 macro_rules! read_tlv_fields {
 708         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => { {
 709                 let tlv_len: $crate::util::ser::BigSize = $crate::util::ser::Readable::read($stream)?;
 710                 let mut rd = $crate::util::ser::FixedLengthReader::new($stream, tlv_len.0);
 711                 $crate::decode_tlv_stream!(&mut rd, {$(($type, $field, $fieldty)),*});
 712                 rd.eat_remaining().map_err(|_| $crate::ln::msgs::DecodeError::ShortRead)?;
 713         } }
 714 }
 715
 716 /// Initializes the struct fields.
 717 ///
 718 /// This is exported for use by other exported macros, do not use directly.
 719 #[doc(hidden)]
 720 #[macro_export]
 721 macro_rules! _init_tlv_based_struct_field {
 722         ($field: ident, (default_value, $default: expr)) => {
 723                 $field.0.unwrap()
 724         };
 725         ($field: ident, (static_value, $value: expr)) => {
 726                 $field
 727         };
 728         ($field: ident, option) => {
 729                 $field
 730         };
 731         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 732                 $crate::_init_tlv_based_struct_field!($field, option)
 733         };
 734         ($field: ident, upgradable_required) => {
 735                 $field.0.unwrap()
 736         };
 737         ($field: ident, upgradable_option) => {
 738                 $field
 739         };
 740         ($field: ident, required) => {
 741                 $field.0.unwrap()
 742         };
 743         ($field: ident, required_vec) => {
 744                 $field
 745         };
 746         ($field: ident, optional_vec) => {
 747                 $field.unwrap()
 748         };
 749 }
 750
 751 /// Initializes the variable we are going to read the TLV into.
 752 ///
 753 /// This is exported for use by other exported macros, do not use directly.
 754 #[doc(hidden)]
 755 #[macro_export]
 756 macro_rules! _init_tlv_field_var {
 757         ($field: ident, (default_value, $default: expr)) => {
 758                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 759         };
 760         ($field: ident, (static_value, $value: expr)) => {
 761                 let $field;
 762         };
 763         ($field: ident, required) => {
 764                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 765         };
 766         ($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
 767                 $crate::_init_tlv_field_var!($field, required);
 768         };
 769         ($field: ident, required_vec) => {
 770                 let mut $field = Vec::new();
 771         };
 772         ($field: ident, option) => {
 773                 let mut $field = None;
 774         };
 775         ($field: ident, optional_vec) => {
 776                 let mut $field = Some(Vec::new());
 777         };
 778         ($field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
 779                 $crate::_init_tlv_field_var!($field, option);
 780         };
 781         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 782                 $crate::_init_tlv_field_var!($field, option);
 783         };
 784         ($field: ident, upgradable_required) => {
 785                 let mut $field = $crate::util::ser::UpgradableRequired(None);
 786         };
 787         ($field: ident, upgradable_option) => {
 788                 let mut $field = None;
 789         };
 790 }
 791
 792 /// Equivalent to running [`_init_tlv_field_var`] then [`read_tlv_fields`].
 793 ///
 794 /// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
 795 /// `i64`.
 796 ///
 797 /// This is exported for use by other exported macros, do not use directly.
 798 #[doc(hidden)]
 799 #[macro_export]
 800 macro_rules! _init_and_read_len_prefixed_tlv_fields {
 801         ($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, $fieldty)),*
 808                 });
 809         }
 810 }
 811
 812 /// Equivalent to running [`_init_tlv_field_var`] then [`decode_tlv_stream`].
 813 ///
 814 /// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
 815 /// `i64`.
 816 macro_rules! _init_and_read_tlv_stream {
 817         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 818                 $(
 819                         $crate::_init_tlv_field_var!($field, $fieldty);
 820                 )*
 821
 822                 $crate::decode_tlv_stream!($reader, {
 823                         $(($type, $field, $fieldty)),*
 824                 });
 825         }
 826 }
 827
 828 /// Implements [`Readable`]/[`Writeable`] for a struct storing it as a set of TLVs
 829 /// If `$fieldty` is `required`, then `$field` is a required field that is not an [`Option`] nor a [`Vec`].
 830 /// If `$fieldty` is `(default_value, $default)`, then `$field` will be set to `$default` if not present.
 831 /// If `$fieldty` is `option`, then `$field` is optional field.
 832 /// If `$fieldty` is `optional_vec`, then `$field` is a [`Vec`], which needs to have its individual elements serialized.
 833 ///    Note that for `optional_vec` no bytes are written if the vec is empty
 834 ///
 835 /// For example,
 836 /// ```
 837 /// # use lightning::impl_writeable_tlv_based;
 838 /// struct LightningMessage {
 839 ///     tlv_integer: u32,
 840 ///     tlv_default_integer: u32,
 841 ///     tlv_optional_integer: Option<u32>,
 842 ///     tlv_vec_type_integer: Vec<u32>,
 843 /// }
 844 ///
 845 /// impl_writeable_tlv_based!(LightningMessage, {
 846 ///     (0, tlv_integer, required),
 847 ///     (1, tlv_default_integer, (default_value, 7)),
 848 ///     (2, tlv_optional_integer, option),
 849 ///     (3, tlv_vec_type_integer, optional_vec),
 850 /// });
 851 /// ```
 852 ///
 853 /// [`Readable`]: crate::util::ser::Readable
 854 /// [`Writeable`]: crate::util::ser::Writeable
 855 #[macro_export]
 856 macro_rules! impl_writeable_tlv_based {
 857         ($st: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 858                 impl $crate::util::ser::Writeable for $st {
 859                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 860                                 $crate::write_tlv_fields!(writer, {
 861                                         $(($type, self.$field, $fieldty)),*
 862                                 });
 863                                 Ok(())
 864                         }
 865
 866                         #[inline]
 867                         fn serialized_length(&self) -> usize {
 868                                 use $crate::util::ser::BigSize;
 869                                 let len = {
 870                                         #[allow(unused_mut)]
 871                                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 872                                         $(
 873                                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, self.$field, $fieldty);
 874                                         )*
 875                                         len.0
 876                                 };
 877                                 let mut len_calc = $crate::util::ser::LengthCalculatingWriter(0);
 878                                 BigSize(len as u64).write(&mut len_calc).expect("No in-memory data may fail to serialize");
 879                                 len + len_calc.0
 880                         }
 881                 }
 882
 883                 impl $crate::util::ser::Readable for $st {
 884                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 885                                 $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
 886                                         $(($type, $field, $fieldty)),*
 887                                 });
 888                                 Ok(Self {
 889                                         $(
 890                                                 $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
 891                                         ),*
 892                                 })
 893                         }
 894                 }
 895         }
 896 }
 897
 898 /// Defines a struct for a TLV stream and a similar struct using references for non-primitive types,
 899 /// implementing [`Readable`] for the former and [`Writeable`] for the latter. Useful as an
 900 /// intermediary format when reading or writing a type encoded as a TLV stream. Note that each field
 901 /// representing a TLV record has its type wrapped with an [`Option`]. A tuple consisting of a type
 902 /// and a serialization wrapper may be given in place of a type when custom serialization is
 903 /// required.
 904 ///
 905 /// [`Readable`]: crate::util::ser::Readable
 906 /// [`Writeable`]: crate::util::ser::Writeable
 907 macro_rules! tlv_stream {
 908         ($name:ident, $nameref:ident, $range:expr, {
 909                 $(($type:expr, $field:ident : $fieldty:tt)),* $(,)*
 910         }) => {
 911                 #[derive(Debug)]
 912                 pub(super) struct $name {
 913                         $(
 914                                 pub(super) $field: Option<tlv_record_type!($fieldty)>,
 915                         )*
 916                 }
 917
 918                 #[cfg_attr(test, derive(PartialEq))]
 919                 #[derive(Debug)]
 920                 pub(crate) struct $nameref<'a> {
 921                         $(
 922                                 pub(super) $field: Option<tlv_record_ref_type!($fieldty)>,
 923                         )*
 924                 }
 925
 926                 impl<'a> $crate::util::ser::Writeable for $nameref<'a> {
 927                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 928                                 encode_tlv_stream!(writer, {
 929                                         $(($type, self.$field, (option, encoding: $fieldty))),*
 930                                 });
 931                                 Ok(())
 932                         }
 933                 }
 934
 935                 impl $crate::util::ser::SeekReadable for $name {
 936                         fn read<R: $crate::io::Read + $crate::io::Seek>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 937                                 $(
 938                                         _init_tlv_field_var!($field, option);
 939                                 )*
 940                                 let rewind = |cursor: &mut R, offset: usize| {
 941                                         cursor.seek($crate::io::SeekFrom::Current(-(offset as i64))).expect("");
 942                                 };
 943                                 _decode_tlv_stream_range!(reader, $range, rewind, {
 944                                         $(($type, $field, (option, encoding: $fieldty))),*
 945                                 });
 946
 947                                 Ok(Self {
 948                                         $(
 949                                                 $field: $field
 950                                         ),*
 951                                 })
 952                         }
 953                 }
 954         }
 955 }
 956
 957 macro_rules! tlv_record_type {
 958         (($type:ty, $wrapper:ident)) => { $type };
 959         (($type:ty, $wrapper:ident, $encoder:ty)) => { $type };
 960         ($type:ty) => { $type };
 961 }
 962
 963 macro_rules! tlv_record_ref_type {
 964         (char) => { char };
 965         (u8) => { u8 };
 966         ((u16, $wrapper: ident)) => { u16 };
 967         ((u32, $wrapper: ident)) => { u32 };
 968         ((u64, $wrapper: ident)) => { u64 };
 969         (($type:ty, $wrapper:ident)) => { &'a $type };
 970         (($type:ty, $wrapper:ident, $encoder:ty)) => { $encoder };
 971         ($type:ty) => { &'a $type };
 972 }
 973
 974 #[doc(hidden)]
 975 #[macro_export]
 976 macro_rules! _impl_writeable_tlv_based_enum_common {
 977         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 978                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 979         ),* $(,)*;
 980         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
 981                 impl $crate::util::ser::Writeable for $st {
 982                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 983                                 match self {
 984                                         $($st::$variant_name { $(ref $field),* } => {
 985                                                 let id: u8 = $variant_id;
 986                                                 id.write(writer)?;
 987                                                 $crate::write_tlv_fields!(writer, {
 988                                                         $(($type, *$field, $fieldty)),*
 989                                                 });
 990                                         }),*
 991                                         $($st::$tuple_variant_name (ref field) => {
 992                                                 let id: u8 = $tuple_variant_id;
 993                                                 id.write(writer)?;
 994                                                 field.write(writer)?;
 995                                         }),*
 996                                 }
 997                                 Ok(())
 998                         }
 999                 }
1000         }
1001 }
1002
1003 /// Implement [`Readable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and tuple
1004 /// variants stored directly.
1005 /// The format is, for example
1006 /// ```ignore
1007 /// impl_writeable_tlv_based_enum!(EnumName,
1008 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
1009 ///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, optional_vec)};
1010 ///   (2, TupleVariantA), (3, TupleVariantB),
1011 /// );
1012 /// ```
1013 /// The type is written as a single byte, followed by any variant data.
1014 /// Attempts to read an unknown type byte result in [`DecodeError::UnknownRequiredFeature`].
1015 ///
1016 /// [`Readable`]: crate::util::ser::Readable
1017 /// [`Writeable`]: crate::util::ser::Writeable
1018 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1019 #[macro_export]
1020 macro_rules! impl_writeable_tlv_based_enum {
1021         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1022                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1023         ),* $(,)*;
1024         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
1025                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1026                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1027                         $(($tuple_variant_id, $tuple_variant_name)),*);
1028
1029                 impl $crate::util::ser::Readable for $st {
1030                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
1031                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1032                                 match id {
1033                                         $($variant_id => {
1034                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1035                                                 // in the same function body. Instead, we define a closure and call it.
1036                                                 let f = || {
1037                                                         $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
1038                                                                 $(($type, $field, $fieldty)),*
1039                                                         });
1040                                                         Ok($st::$variant_name {
1041                                                                 $(
1042                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1043                                                                 ),*
1044                                                         })
1045                                                 };
1046                                                 f()
1047                                         }),*
1048                                         $($tuple_variant_id => {
1049                                                 Ok($st::$tuple_variant_name($crate::util::ser::Readable::read(reader)?))
1050                                         }),*
1051                                         _ => {
1052                                                 Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature)
1053                                         },
1054                                 }
1055                         }
1056                 }
1057         }
1058 }
1059
1060 /// Implement [`MaybeReadable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and
1061 /// tuple variants stored directly.
1062 ///
1063 /// This is largely identical to [`impl_writeable_tlv_based_enum`], except that odd variants will
1064 /// return `Ok(None)` instead of `Err(`[`DecodeError::UnknownRequiredFeature`]`)`. It should generally be preferred
1065 /// when [`MaybeReadable`] is practical instead of just [`Readable`] as it provides an upgrade path for
1066 /// new variants to be added which are simply ignored by existing clients.
1067 ///
1068 /// [`MaybeReadable`]: crate::util::ser::MaybeReadable
1069 /// [`Writeable`]: crate::util::ser::Writeable
1070 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1071 /// [`Readable`]: crate::util::ser::Readable
1072 #[macro_export]
1073 macro_rules! impl_writeable_tlv_based_enum_upgradable {
1074         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1075                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1076         ),* $(,)*
1077         $(;
1078         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
1079                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1080                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1081                         $($(($tuple_variant_id, $tuple_variant_name)),*)*);
1082
1083                 impl $crate::util::ser::MaybeReadable for $st {
1084                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Option<Self>, $crate::ln::msgs::DecodeError> {
1085                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1086                                 match id {
1087                                         $($variant_id => {
1088                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1089                                                 // in the same function body. Instead, we define a closure and call it.
1090                                                 let f = || {
1091                                                         $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
1092                                                                 $(($type, $field, $fieldty)),*
1093                                                         });
1094                                                         Ok(Some($st::$variant_name {
1095                                                                 $(
1096                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1097                                                                 ),*
1098                                                         }))
1099                                                 };
1100                                                 f()
1101                                         }),*
1102                                         $($($tuple_variant_id => {
1103                                                 Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
1104                                         }),*)*
1105                                         _ if id % 2 == 1 => Ok(None),
1106                                         _ => Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature),
1107                                 }
1108                         }
1109                 }
1110         }
1111 }
1112
1113 #[cfg(test)]
1114 mod tests {
1115         use crate::io::{self, Cursor};
1116         use crate::prelude::*;
1117         use crate::ln::msgs::DecodeError;
1118         use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
1119         use bitcoin::hashes::hex::FromHex;
1120         use bitcoin::secp256k1::PublicKey;
1121
1122         // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
1123         // the encoding layer in the BOLTs has no such concept, though it makes our macros easier to
1124         // work with so they're baked into the decoder. Thus, we have a few additional tests below
1125         fn tlv_reader(s: &[u8]) -> Result<(u64, u32, Option<u32>), DecodeError> {
1126                 let mut s = Cursor::new(s);
1127                 let mut a: u64 = 0;
1128                 let mut b: u32 = 0;
1129                 let mut c: Option<u32> = None;
1130                 decode_tlv_stream!(&mut s, {(2, a, required), (3, b, required), (4, c, option)});
1131                 Ok((a, b, c))
1132         }
1133
1134         #[test]
1135         fn tlv_v_short_read() {
1136                 // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
1137                 if let Err(DecodeError::ShortRead) = tlv_reader(&<Vec<u8>>::from_hex(
1138                                 concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
1139                                 ).unwrap()[..]) {
1140                 } else { panic!(); }
1141         }
1142
1143         #[test]
1144         fn tlv_types_out_of_order() {
1145                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1146                                 concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
1147                                 ).unwrap()[..]) {
1148                 } else { panic!(); }
1149                 // ...even if its some field we don't understand
1150                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1151                                 concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
1152                                 ).unwrap()[..]) {
1153                 } else { panic!(); }
1154         }
1155
1156         #[test]
1157         fn tlv_req_type_missing_or_extra() {
1158                 // It's also bad if they included even fields we don't understand
1159                 if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&<Vec<u8>>::from_hex(
1160                                 concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
1161                                 ).unwrap()[..]) {
1162                 } else { panic!(); }
1163                 // ... or if they're missing fields we need
1164                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1165                                 concat!("0100", "0208deadbeef1badbeef")
1166                                 ).unwrap()[..]) {
1167                 } else { panic!(); }
1168                 // ... even if that field is even
1169                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1170                                 concat!("0304deadbeef", "0500")
1171                                 ).unwrap()[..]) {
1172                 } else { panic!(); }
1173         }
1174
1175         #[test]
1176         fn tlv_simple_good_cases() {
1177                 assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
1178                                 concat!("0208deadbeef1badbeef", "03041bad1dea")
1179                                 ).unwrap()[..]).unwrap(),
1180                         (0xdeadbeef1badbeef, 0x1bad1dea, None));
1181                 assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
1182                                 concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
1183                                 ).unwrap()[..]).unwrap(),
1184                         (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
1185         }
1186
1187         #[derive(Debug, PartialEq)]
1188         struct TestUpgradable {
1189                 a: u32,
1190                 b: u32,
1191                 c: Option<u32>,
1192         }
1193
1194         fn upgradable_tlv_reader(s: &[u8]) -> Result<Option<TestUpgradable>, DecodeError> {
1195                 let mut s = Cursor::new(s);
1196                 let mut a = 0;
1197                 let mut b = 0;
1198                 let mut c: Option<u32> = None;
1199                 decode_tlv_stream!(&mut s, {(2, a, upgradable_required), (3, b, upgradable_required), (4, c, upgradable_option)});
1200                 Ok(Some(TestUpgradable { a, b, c, }))
1201         }
1202
1203         #[test]
1204         fn upgradable_tlv_simple_good_cases() {
1205                 assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1206                         concat!("0204deadbeef", "03041bad1dea", "0404deadbeef")
1207                 ).unwrap()[..]).unwrap(),
1208                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: Some(0xdeadbeef) }));
1209
1210                 assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1211                         concat!("0204deadbeef", "03041bad1dea")
1212                 ).unwrap()[..]).unwrap(),
1213                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: None}));
1214         }
1215
1216         #[test]
1217         fn missing_required_upgradable() {
1218                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1219                         concat!("0100", "0204deadbeef")
1220                         ).unwrap()[..]) {
1221                 } else { panic!(); }
1222                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1223                         concat!("0100", "03041bad1dea")
1224                 ).unwrap()[..]) {
1225                 } else { panic!(); }
1226         }
1227
1228         // BOLT TLV test cases
1229         fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
1230                 let mut s = Cursor::new(s);
1231                 let mut tlv1: Option<HighZeroBytesDroppedBigSize<u64>> = None;
1232                 let mut tlv2: Option<u64> = None;
1233                 let mut tlv3: Option<(PublicKey, u64, u64)> = None;
1234                 let mut tlv4: Option<u16> = None;
1235                 decode_tlv_stream!(&mut s, {(1, tlv1, option), (2, tlv2, option), (3, tlv3, option), (254, tlv4, option)});
1236                 Ok((tlv1, tlv2, tlv3, tlv4))
1237         }
1238
1239         #[test]
1240         fn bolt_tlv_bogus_stream() {
1241                 macro_rules! do_test {
1242                         ($stream: expr, $reason: ident) => {
1243                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1244                                 } else { panic!(); }
1245                         }
1246                 }
1247
1248                 // TLVs from the BOLT test cases which should not decode as either n1 or n2
1249                 do_test!(concat!("fd01"), ShortRead);
1250                 do_test!(concat!("fd0001", "00"), InvalidValue);
1251                 do_test!(concat!("fd0101"), ShortRead);
1252                 do_test!(concat!("0f", "fd"), ShortRead);
1253                 do_test!(concat!("0f", "fd26"), ShortRead);
1254                 do_test!(concat!("0f", "fd2602"), ShortRead);
1255                 do_test!(concat!("0f", "fd0001", "00"), InvalidValue);
1256                 do_test!(concat!("0f", "fd0201", "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"), ShortRead);
1257
1258                 do_test!(concat!("12", "00"), UnknownRequiredFeature);
1259                 do_test!(concat!("fd0102", "00"), UnknownRequiredFeature);
1260                 do_test!(concat!("fe01000002", "00"), UnknownRequiredFeature);
1261                 do_test!(concat!("ff0100000000000002", "00"), UnknownRequiredFeature);
1262         }
1263
1264         #[test]
1265         fn bolt_tlv_bogus_n1_stream() {
1266                 macro_rules! do_test {
1267                         ($stream: expr, $reason: ident) => {
1268                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1269                                 } else { panic!(); }
1270                         }
1271                 }
1272
1273                 // TLVs from the BOLT test cases which should not decode as n1
1274                 do_test!(concat!("01", "09", "ffffffffffffffffff"), InvalidValue);
1275                 do_test!(concat!("01", "01", "00"), InvalidValue);
1276                 do_test!(concat!("01", "02", "0001"), InvalidValue);
1277                 do_test!(concat!("01", "03", "000100"), InvalidValue);
1278                 do_test!(concat!("01", "04", "00010000"), InvalidValue);
1279                 do_test!(concat!("01", "05", "0001000000"), InvalidValue);
1280                 do_test!(concat!("01", "06", "000100000000"), InvalidValue);
1281                 do_test!(concat!("01", "07", "00010000000000"), InvalidValue);
1282                 do_test!(concat!("01", "08", "0001000000000000"), InvalidValue);
1283                 do_test!(concat!("02", "07", "01010101010101"), ShortRead);
1284                 do_test!(concat!("02", "09", "010101010101010101"), InvalidValue);
1285                 do_test!(concat!("03", "21", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb"), ShortRead);
1286                 do_test!(concat!("03", "29", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001"), ShortRead);
1287                 do_test!(concat!("03", "30", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb000000000000000100000000000001"), ShortRead);
1288                 do_test!(concat!("03", "31", "043da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"), InvalidValue);
1289                 do_test!(concat!("03", "32", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001000000000000000001"), InvalidValue);
1290                 do_test!(concat!("fd00fe", "00"), ShortRead);
1291                 do_test!(concat!("fd00fe", "01", "01"), ShortRead);
1292                 do_test!(concat!("fd00fe", "03", "010101"), InvalidValue);
1293                 do_test!(concat!("00", "00"), UnknownRequiredFeature);
1294
1295                 do_test!(concat!("02", "08", "0000000000000226", "01", "01", "2a"), InvalidValue);
1296                 do_test!(concat!("02", "08", "0000000000000231", "02", "08", "0000000000000451"), InvalidValue);
1297                 do_test!(concat!("1f", "00", "0f", "01", "2a"), InvalidValue);
1298                 do_test!(concat!("1f", "00", "1f", "01", "2a"), InvalidValue);
1299
1300                 // The last BOLT test modified to not require creating a new decoder for one trivial test.
1301                 do_test!(concat!("ffffffffffffffffff", "00", "01", "00"), InvalidValue);
1302         }
1303
1304         #[test]
1305         fn bolt_tlv_valid_n1_stream() {
1306                 macro_rules! do_test {
1307                         ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
1308                                 if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1309                                         assert_eq!(tlv1.map(|v| v.0), $tlv1);
1310                                         assert_eq!(tlv2, $tlv2);
1311                                         assert_eq!(tlv3, $tlv3);
1312                                         assert_eq!(tlv4, $tlv4);
1313                                 } else { panic!(); }
1314                         }
1315                 }
1316
1317                 do_test!(concat!(""), None, None, None, None);
1318                 do_test!(concat!("21", "00"), None, None, None, None);
1319                 do_test!(concat!("fd0201", "00"), None, None, None, None);
1320                 do_test!(concat!("fd00fd", "00"), None, None, None, None);
1321                 do_test!(concat!("fd00ff", "00"), None, None, None, None);
1322                 do_test!(concat!("fe02000001", "00"), None, None, None, None);
1323                 do_test!(concat!("ff0200000000000001", "00"), None, None, None, None);
1324
1325                 do_test!(concat!("01", "00"), Some(0), None, None, None);
1326                 do_test!(concat!("01", "01", "01"), Some(1), None, None, None);
1327                 do_test!(concat!("01", "02", "0100"), Some(256), None, None, None);
1328                 do_test!(concat!("01", "03", "010000"), Some(65536), None, None, None);
1329                 do_test!(concat!("01", "04", "01000000"), Some(16777216), None, None, None);
1330                 do_test!(concat!("01", "05", "0100000000"), Some(4294967296), None, None, None);
1331                 do_test!(concat!("01", "06", "010000000000"), Some(1099511627776), None, None, None);
1332                 do_test!(concat!("01", "07", "01000000000000"), Some(281474976710656), None, None, None);
1333                 do_test!(concat!("01", "08", "0100000000000000"), Some(72057594037927936), None, None, None);
1334                 do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
1335                 do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
1336                         None, None, Some((
1337                                 PublicKey::from_slice(&<Vec<u8>>::from_hex("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
1338                         None);
1339                 do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
1340         }
1341
1342         fn do_simple_test_tlv_write() -> Result<(), io::Error> {
1343                 let mut stream = VecWriter(Vec::new());
1344
1345                 stream.0.clear();
1346                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
1347                 assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
1348
1349                 stream.0.clear();
1350                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
1351                 assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
1352
1353                 stream.0.clear();
1354                 _encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
1355                 assert_eq!(stream.0, <Vec<u8>>::from_hex("040402abcd").unwrap());
1356
1357                 stream.0.clear();
1358                 _encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
1359                 assert_eq!(stream.0, <Vec<u8>>::from_hex("06fd00ff02abcd").unwrap());
1360
1361                 stream.0.clear();
1362                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1363                 assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
1364
1365                 stream.0.clear();
1366                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1367                 assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
1368
1369                 Ok(())
1370         }
1371
1372         #[test]
1373         fn simple_test_tlv_write() {
1374                 do_simple_test_tlv_write().unwrap();
1375         }
1376 }