_ 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: $encoding: tt)) => {{
 348                 // no-op
 349         }};
 350 }
 351
 352 /// Implements deserialization for a single TLV record.
 353 /// This is exported for use by other exported macros, do not use directly.
 354 #[doc(hidden)]
 355 #[macro_export]
 356 macro_rules! _decode_tlv {
 357         ($outer_reader: expr, $reader: expr, $field: ident, (default_value, $default: expr)) => {{
 358                 $crate::_decode_tlv!($outer_reader, $reader, $field, required)
 359         }};
 360         ($outer_reader: expr, $reader: expr, $field: ident, (static_value, $value: expr)) => {{
 361         }};
 362         ($outer_reader: expr, $reader: expr, $field: ident, required) => {{
 363                 $field = $crate::util::ser::Readable::read(&mut $reader)?;
 364         }};
 365         ($outer_reader: expr, $reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 366                 $field = $trait::read(&mut $reader $(, $read_arg)*)?;
 367         }};
 368         ($outer_reader: expr, $reader: expr, $field: ident, required_vec) => {{
 369                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 370                 $field = f.0;
 371         }};
 372         ($outer_reader: expr, $reader: expr, $field: ident, option) => {{
 373                 $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
 374         }};
 375         ($outer_reader: expr, $reader: expr, $field: ident, optional_vec) => {{
 376                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 377                 $field = Some(f.0);
 378         }};
 379         // `upgradable_required` indicates we're reading a required TLV that may have been upgraded
 380         // without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
 381         // field is present but we can no longer understand it.
 382         // Note that this variant can only be used within a `MaybeReadable` read.
 383         ($outer_reader: expr, $reader: expr, $field: ident, upgradable_required) => {{
 384                 $field = match $crate::util::ser::MaybeReadable::read(&mut $reader)? {
 385                         Some(res) => res,
 386                         None => {
 387                                 // If we successfully read a value but we don't know how to parse it, we give up
 388                                 // and immediately return `None`. However, we need to make sure we read the correct
 389                                 // number of bytes for this TLV stream, which is implicitly the end of the stream.
 390                                 // Thus, we consume everything left in the `$outer_reader` here, ensuring that if
 391                                 // we're being read as a part of another TLV stream we don't spuriously fail to
 392                                 // deserialize the outer object due to a TLV length mismatch.
 393                                 $crate::io_extras::copy($outer_reader, &mut $crate::io_extras::sink()).unwrap();
 394                                 return Ok(None)
 395                         },
 396                 };
 397         }};
 398         // `upgradable_option` indicates we're reading an Option-al TLV that may have been upgraded
 399         // without backwards compat. $field will be None if the TLV is missing or if the field is present
 400         // but we can no longer understand it.
 401         ($outer_reader: expr, $reader: expr, $field: ident, upgradable_option) => {{
 402                 $field = $crate::util::ser::MaybeReadable::read(&mut $reader)?;
 403                 if $field.is_none() {
 404                         #[cfg(not(debug_assertions))] {
 405                                 // In general, MaybeReadable implementations are required to consume all the bytes
 406                                 // of the object even if they don't understand it, but due to a bug in the
 407                                 // serialization format for `impl_writeable_tlv_based_enum_upgradable` we sometimes
 408                                 // don't know how many bytes that is. In such cases, we'd like to spuriously allow
 409                                 // TLV length mismatches, which we do here by calling `eat_remaining` so that the
 410                                 // `s.bytes_remain()` check in `_decode_tlv_stream_range` doesn't fail.
 411                                 $reader.eat_remaining()?;
 412                         }
 413                 }
 414         }};
 415         ($outer_reader: expr, $reader: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 416                 $field = Some($trait::read(&mut $reader $(, $read_arg)*)?);
 417         }};
 418         ($outer_reader: expr, $reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident, $encoder:ty))) => {{
 419                 $crate::_decode_tlv!($outer_reader, $reader, $field, (option, encoding: ($fieldty, $encoding)));
 420         }};
 421         ($outer_reader: expr, $reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {{
 422                 $field = {
 423                         let field: $encoding<$fieldty> = ser::Readable::read(&mut $reader)?;
 424                         Some(field.0)
 425                 };
 426         }};
 427         ($outer_reader: expr, $reader: expr, $field: ident, (option, encoding: $fieldty: ty)) => {{
 428                 $crate::_decode_tlv!($outer_reader, $reader, $field, option);
 429         }};
 430 }
 431
 432 /// Checks if `$val` matches `$type`.
 433 /// This is exported for use by other exported macros, do not use directly.
 434 #[doc(hidden)]
 435 #[macro_export]
 436 macro_rules! _decode_tlv_stream_match_check {
 437         ($val: ident, $type: expr, (static_value, $value: expr)) => { false };
 438         ($val: ident, $type: expr, $fieldty: tt) => { $val == $type }
 439 }
 440
 441 /// Implements the TLVs deserialization part in a [`Readable`] implementation of a struct.
 442 ///
 443 /// This should be called inside a method which returns `Result<_, `[`DecodeError`]`>`, such as
 444 /// [`Readable::read`]. It will either return an `Err` or ensure all `required` fields have been
 445 /// read and optionally read `optional` fields.
 446 ///
 447 /// `$stream` must be a [`Read`] and will be fully consumed, reading until no more bytes remain
 448 /// (i.e. it returns [`DecodeError::ShortRead`]).
 449 ///
 450 /// Fields MUST be sorted in `$type`-order.
 451 ///
 452 /// Note that the lightning TLV requirements require that a single type not appear more than once,
 453 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
 454 /// decoder.
 455 ///
 456 /// For example,
 457 /// ```
 458 /// # use lightning::decode_tlv_stream;
 459 /// # fn read<R: lightning::io::Read> (stream: R) -> Result<(), lightning::ln::msgs::DecodeError> {
 460 /// let mut required_value = 0u64;
 461 /// let mut optional_value: Option<u64> = None;
 462 /// decode_tlv_stream!(stream, {
 463 ///     (0, required_value, required),
 464 ///     (2, optional_value, option),
 465 /// });
 466 /// // At this point, `required_value` has been overwritten with the TLV with type 0.
 467 /// // `optional_value` may have been overwritten, setting it to `Some` if a TLV with type 2 was
 468 /// // present.
 469 /// # Ok(())
 470 /// # }
 471 /// ```
 472 ///
 473 /// [`Readable`]: crate::util::ser::Readable
 474 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 475 /// [`Readable::read`]: crate::util::ser::Readable::read
 476 /// [`Read`]: crate::io::Read
 477 /// [`DecodeError::ShortRead`]: crate::ln::msgs::DecodeError::ShortRead
 478 #[macro_export]
 479 macro_rules! decode_tlv_stream {
 480         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 481                 let rewind = |_, _| { unreachable!() };
 482                 $crate::_decode_tlv_stream_range!($stream, .., rewind, {$(($type, $field, $fieldty)),*});
 483         }
 484 }
 485
 486 /// Similar to [`decode_tlv_stream`] with a custom TLV decoding capabilities.
 487 ///
 488 /// `$decode_custom_tlv` is a closure that may be optionally provided to handle custom message types.
 489 /// If it is provided, it will be called with the custom type and the [`FixedLengthReader`] containing
 490 /// the message contents. It should return `Ok(true)` if the custom message is successfully parsed,
 491 /// `Ok(false)` if the message type is unknown, and `Err(`[`DecodeError`]`)` if parsing fails.
 492 ///
 493 /// [`FixedLengthReader`]: crate::util::ser::FixedLengthReader
 494 /// [`DecodeError`]: crate::ln::msgs::DecodeError
 495 macro_rules! decode_tlv_stream_with_custom_tlv_decode {
 496         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 497          $(, $decode_custom_tlv: expr)?) => { {
 498                 let rewind = |_, _| { unreachable!() };
 499                 _decode_tlv_stream_range!(
 500                         $stream, .., rewind, {$(($type, $field, $fieldty)),*} $(, $decode_custom_tlv)?
 501                 );
 502         } }
 503 }
 504
 505 #[doc(hidden)]
 506 #[macro_export]
 507 macro_rules! _decode_tlv_stream_range {
 508         ($stream: expr, $range: expr, $rewind: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 509          $(, $decode_custom_tlv: expr)?) => { {
 510                 use $crate::ln::msgs::DecodeError;
 511                 let mut last_seen_type: Option<u64> = None;
 512                 let mut stream_ref = $stream;
 513                 'tlv_read: loop {
 514                         use $crate::util::ser;
 515
 516                         // First decode the type of this TLV:
 517                         let typ: ser::BigSize = {
 518                                 // We track whether any bytes were read during the consensus_decode call to
 519                                 // determine whether we should break or return ShortRead if we get an
 520                                 // UnexpectedEof. This should in every case be largely cosmetic, but its nice to
 521                                 // pass the TLV test vectors exactly, which require this distinction.
 522                                 let mut tracking_reader = ser::ReadTrackingReader::new(&mut stream_ref);
 523                                 match <$crate::util::ser::BigSize as $crate::util::ser::Readable>::read(&mut tracking_reader) {
 524                                         Err(DecodeError::ShortRead) => {
 525                                                 if !tracking_reader.have_read {
 526                                                         break 'tlv_read;
 527                                                 } else {
 528                                                         return Err(DecodeError::ShortRead);
 529                                                 }
 530                                         },
 531                                         Err(e) => return Err(e),
 532                                         Ok(t) => if core::ops::RangeBounds::contains(&$range, &t.0) { t } else {
 533                                                 drop(tracking_reader);
 534
 535                                                 // Assumes the type id is minimally encoded, which is enforced on read.
 536                                                 use $crate::util::ser::Writeable;
 537                                                 let bytes_read = t.serialized_length();
 538                                                 $rewind(stream_ref, bytes_read);
 539                                                 break 'tlv_read;
 540                                         },
 541                                 }
 542                         };
 543
 544                         // Types must be unique and monotonically increasing:
 545                         match last_seen_type {
 546                                 Some(t) if typ.0 <= t => {
 547                                         return Err(DecodeError::InvalidValue);
 548                                 },
 549                                 _ => {},
 550                         }
 551                         // As we read types, make sure we hit every required type between `last_seen_type` and `typ`:
 552                         $({
 553                                 $crate::_check_decoded_tlv_order!(last_seen_type, typ, $type, $field, $fieldty);
 554                         })*
 555                         last_seen_type = Some(typ.0);
 556
 557                         // Finally, read the length and value itself:
 558                         let length: ser::BigSize = $crate::util::ser::Readable::read(&mut stream_ref)?;
 559                         let mut s = ser::FixedLengthReader::new(&mut stream_ref, length.0);
 560                         match typ.0 {
 561                                 $(_t if $crate::_decode_tlv_stream_match_check!(_t, $type, $fieldty) => {
 562                                         $crate::_decode_tlv!($stream, s, $field, $fieldty);
 563                                         if s.bytes_remain() {
 564                                                 s.eat_remaining()?; // Return ShortRead if there's actually not enough bytes
 565                                                 return Err(DecodeError::InvalidValue);
 566                                         }
 567                                 },)*
 568                                 t => {
 569                                         $(
 570                                                 if $decode_custom_tlv(t, &mut s)? {
 571                                                         // If a custom TLV was successfully read (i.e. decode_custom_tlv returns true),
 572                                                         // continue to the next TLV read.
 573                                                         s.eat_remaining()?;
 574                                                         continue 'tlv_read;
 575                                                 }
 576                                         )?
 577                                         if t % 2 == 0 {
 578                                                 return Err(DecodeError::UnknownRequiredFeature);
 579                                         }
 580                                 }
 581                         }
 582                         s.eat_remaining()?;
 583                 }
 584                 // Make sure we got to each required type after we've read every TLV:
 585                 $({
 586                         $crate::_check_missing_tlv!(last_seen_type, $type, $field, $fieldty);
 587                 })*
 588         } }
 589 }
 590
 591 /// Implements [`Readable`]/[`Writeable`] for a message struct that may include non-TLV and
 592 /// TLV-encoded parts.
 593 ///
 594 /// This is useful to implement a [`CustomMessageReader`].
 595 ///
 596 /// Currently `$fieldty` may only be `option`, i.e., `$tlvfield` is optional field.
 597 ///
 598 /// For example,
 599 /// ```
 600 /// # use lightning::impl_writeable_msg;
 601 /// struct MyCustomMessage {
 602 ///     pub field_1: u32,
 603 ///     pub field_2: bool,
 604 ///     pub field_3: String,
 605 ///     pub tlv_optional_integer: Option<u32>,
 606 /// }
 607 ///
 608 /// impl_writeable_msg!(MyCustomMessage, {
 609 ///     field_1,
 610 ///     field_2,
 611 ///     field_3
 612 /// }, {
 613 ///     (1, tlv_optional_integer, option),
 614 /// });
 615 /// ```
 616 ///
 617 /// [`Readable`]: crate::util::ser::Readable
 618 /// [`Writeable`]: crate::util::ser::Writeable
 619 /// [`CustomMessageReader`]: crate::ln::wire::CustomMessageReader
 620 #[macro_export]
 621 macro_rules! impl_writeable_msg {
 622         ($st:ident, {$($field:ident),* $(,)*}, {$(($type: expr, $tlvfield: ident, $fieldty: tt)),* $(,)*}) => {
 623                 impl $crate::util::ser::Writeable for $st {
 624                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 625                                 $( self.$field.write(w)?; )*
 626                                 $crate::encode_tlv_stream!(w, {$(($type, self.$tlvfield.as_ref(), $fieldty)),*});
 627                                 Ok(())
 628                         }
 629                 }
 630                 impl $crate::util::ser::Readable for $st {
 631                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 632                                 $(let $field = $crate::util::ser::Readable::read(r)?;)*
 633                                 $($crate::_init_tlv_field_var!($tlvfield, $fieldty);)*
 634                                 $crate::decode_tlv_stream!(r, {$(($type, $tlvfield, $fieldty)),*});
 635                                 Ok(Self {
 636                                         $($field),*,
 637                                         $($tlvfield),*
 638                                 })
 639                         }
 640                 }
 641         }
 642 }
 643
 644 macro_rules! impl_writeable {
 645         ($st:ident, {$($field:ident),*}) => {
 646                 impl $crate::util::ser::Writeable for $st {
 647                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 648                                 $( self.$field.write(w)?; )*
 649                                 Ok(())
 650                         }
 651
 652                         #[inline]
 653                         fn serialized_length(&self) -> usize {
 654                                 let mut len_calc = 0;
 655                                 $( len_calc += self.$field.serialized_length(); )*
 656                                 return len_calc;
 657                         }
 658                 }
 659
 660                 impl $crate::util::ser::Readable for $st {
 661                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 662                                 Ok(Self {
 663                                         $($field: $crate::util::ser::Readable::read(r)?),*
 664                                 })
 665                         }
 666                 }
 667         }
 668 }
 669
 670 /// Write out two bytes to indicate the version of an object.
 671 ///
 672 /// $this_version represents a unique version of a type. Incremented whenever the type's
 673 /// serialization format has changed or has a new interpretation. Used by a type's reader to
 674 /// determine how to interpret fields or if it can understand a serialized object.
 675 ///
 676 /// $min_version_that_can_read_this is the minimum reader version which can understand this
 677 /// serialized object. Previous versions will simply err with a [`DecodeError::UnknownVersion`].
 678 ///
 679 /// Updates to either `$this_version` or `$min_version_that_can_read_this` should be included in
 680 /// release notes.
 681 ///
 682 /// Both version fields can be specific to this type of object.
 683 ///
 684 /// [`DecodeError::UnknownVersion`]: crate::ln::msgs::DecodeError::UnknownVersion
 685 macro_rules! write_ver_prefix {
 686         ($stream: expr, $this_version: expr, $min_version_that_can_read_this: expr) => {
 687                 $stream.write_all(&[$this_version; 1])?;
 688                 $stream.write_all(&[$min_version_that_can_read_this; 1])?;
 689         }
 690 }
 691
 692 /// Writes out a suffix to an object as a length-prefixed TLV stream which contains potentially
 693 /// backwards-compatible, optional fields which old nodes can happily ignore.
 694 ///
 695 /// It is written out in TLV format and, as with all TLV fields, unknown even fields cause a
 696 /// [`DecodeError::UnknownRequiredFeature`] error, with unknown odd fields ignored.
 697 ///
 698 /// This is the preferred method of adding new fields that old nodes can ignore and still function
 699 /// correctly.
 700 ///
 701 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
 702 #[macro_export]
 703 macro_rules! write_tlv_fields {
 704         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
 705                 $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*})
 706         }
 707 }
 708
 709 /// Reads a prefix added by [`write_ver_prefix`], above. Takes the current version of the
 710 /// serialization logic for this object. This is compared against the
 711 /// `$min_version_that_can_read_this` added by [`write_ver_prefix`].
 712 macro_rules! read_ver_prefix {
 713         ($stream: expr, $this_version: expr) => { {
 714                 let ver: u8 = Readable::read($stream)?;
 715                 let min_ver: u8 = Readable::read($stream)?;
 716                 if min_ver > $this_version {
 717                         return Err(DecodeError::UnknownVersion);
 718                 }
 719                 ver
 720         } }
 721 }
 722
 723 /// Reads a suffix added by [`write_tlv_fields`].
 724 ///
 725 /// [`write_tlv_fields`]: crate::write_tlv_fields
 726 #[macro_export]
 727 macro_rules! read_tlv_fields {
 728         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => { {
 729                 let tlv_len: $crate::util::ser::BigSize = $crate::util::ser::Readable::read($stream)?;
 730                 let mut rd = $crate::util::ser::FixedLengthReader::new($stream, tlv_len.0);
 731                 $crate::decode_tlv_stream!(&mut rd, {$(($type, $field, $fieldty)),*});
 732                 rd.eat_remaining().map_err(|_| $crate::ln::msgs::DecodeError::ShortRead)?;
 733         } }
 734 }
 735
 736 /// Initializes the struct fields.
 737 ///
 738 /// This is exported for use by other exported macros, do not use directly.
 739 #[doc(hidden)]
 740 #[macro_export]
 741 macro_rules! _init_tlv_based_struct_field {
 742         ($field: ident, (default_value, $default: expr)) => {
 743                 $field.0.unwrap()
 744         };
 745         ($field: ident, (static_value, $value: expr)) => {
 746                 $field
 747         };
 748         ($field: ident, option) => {
 749                 $field
 750         };
 751         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 752                 $crate::_init_tlv_based_struct_field!($field, option)
 753         };
 754         ($field: ident, upgradable_required) => {
 755                 $field.0.unwrap()
 756         };
 757         ($field: ident, upgradable_option) => {
 758                 $field
 759         };
 760         ($field: ident, required) => {
 761                 $field.0.unwrap()
 762         };
 763         ($field: ident, required_vec) => {
 764                 $field
 765         };
 766         ($field: ident, optional_vec) => {
 767                 $field.unwrap()
 768         };
 769 }
 770
 771 /// Initializes the variable we are going to read the TLV into.
 772 ///
 773 /// This is exported for use by other exported macros, do not use directly.
 774 #[doc(hidden)]
 775 #[macro_export]
 776 macro_rules! _init_tlv_field_var {
 777         ($field: ident, (default_value, $default: expr)) => {
 778                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 779         };
 780         ($field: ident, (static_value, $value: expr)) => {
 781                 let $field;
 782         };
 783         ($field: ident, required) => {
 784                 let mut $field = $crate::util::ser::RequiredWrapper(None);
 785         };
 786         ($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
 787                 $crate::_init_tlv_field_var!($field, required);
 788         };
 789         ($field: ident, required_vec) => {
 790                 let mut $field = Vec::new();
 791         };
 792         ($field: ident, option) => {
 793                 let mut $field = None;
 794         };
 795         ($field: ident, optional_vec) => {
 796                 let mut $field = Some(Vec::new());
 797         };
 798         ($field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
 799                 $crate::_init_tlv_field_var!($field, option);
 800         };
 801         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
 802                 $crate::_init_tlv_field_var!($field, option);
 803         };
 804         ($field: ident, upgradable_required) => {
 805                 let mut $field = $crate::util::ser::UpgradableRequired(None);
 806         };
 807         ($field: ident, upgradable_option) => {
 808                 let mut $field = None;
 809         };
 810 }
 811
 812 /// Equivalent to running [`_init_tlv_field_var`] then [`read_tlv_fields`].
 813 ///
 814 /// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
 815 /// `i64`.
 816 ///
 817 /// This is exported for use by other exported macros, do not use directly.
 818 #[doc(hidden)]
 819 #[macro_export]
 820 macro_rules! _init_and_read_len_prefixed_tlv_fields {
 821         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 822                 $(
 823                         $crate::_init_tlv_field_var!($field, $fieldty);
 824                 )*
 825
 826                 $crate::read_tlv_fields!($reader, {
 827                         $(($type, $field, $fieldty)),*
 828                 });
 829         }
 830 }
 831
 832 /// Equivalent to running [`_init_tlv_field_var`] then [`decode_tlv_stream`].
 833 ///
 834 /// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
 835 /// `i64`.
 836 macro_rules! _init_and_read_tlv_stream {
 837         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 838                 $(
 839                         $crate::_init_tlv_field_var!($field, $fieldty);
 840                 )*
 841
 842                 $crate::decode_tlv_stream!($reader, {
 843                         $(($type, $field, $fieldty)),*
 844                 });
 845         }
 846 }
 847
 848 /// Implements [`Readable`]/[`Writeable`] for a struct storing it as a set of TLVs
 849 /// If `$fieldty` is `required`, then `$field` is a required field that is not an [`Option`] nor a [`Vec`].
 850 /// If `$fieldty` is `(default_value, $default)`, then `$field` will be set to `$default` if not present.
 851 /// If `$fieldty` is `option`, then `$field` is optional field.
 852 /// If `$fieldty` is `optional_vec`, then `$field` is a [`Vec`], which needs to have its individual elements serialized.
 853 ///    Note that for `optional_vec` no bytes are written if the vec is empty
 854 ///
 855 /// For example,
 856 /// ```
 857 /// # use lightning::impl_writeable_tlv_based;
 858 /// struct LightningMessage {
 859 ///     tlv_integer: u32,
 860 ///     tlv_default_integer: u32,
 861 ///     tlv_optional_integer: Option<u32>,
 862 ///     tlv_vec_type_integer: Vec<u32>,
 863 /// }
 864 ///
 865 /// impl_writeable_tlv_based!(LightningMessage, {
 866 ///     (0, tlv_integer, required),
 867 ///     (1, tlv_default_integer, (default_value, 7)),
 868 ///     (2, tlv_optional_integer, option),
 869 ///     (3, tlv_vec_type_integer, optional_vec),
 870 /// });
 871 /// ```
 872 ///
 873 /// [`Readable`]: crate::util::ser::Readable
 874 /// [`Writeable`]: crate::util::ser::Writeable
 875 #[macro_export]
 876 macro_rules! impl_writeable_tlv_based {
 877         ($st: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 878                 impl $crate::util::ser::Writeable for $st {
 879                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 880                                 $crate::write_tlv_fields!(writer, {
 881                                         $(($type, self.$field, $fieldty)),*
 882                                 });
 883                                 Ok(())
 884                         }
 885
 886                         #[inline]
 887                         fn serialized_length(&self) -> usize {
 888                                 use $crate::util::ser::BigSize;
 889                                 let len = {
 890                                         #[allow(unused_mut)]
 891                                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 892                                         $(
 893                                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, self.$field, $fieldty);
 894                                         )*
 895                                         len.0
 896                                 };
 897                                 let mut len_calc = $crate::util::ser::LengthCalculatingWriter(0);
 898                                 BigSize(len as u64).write(&mut len_calc).expect("No in-memory data may fail to serialize");
 899                                 len + len_calc.0
 900                         }
 901                 }
 902
 903                 impl $crate::util::ser::Readable for $st {
 904                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 905                                 $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
 906                                         $(($type, $field, $fieldty)),*
 907                                 });
 908                                 Ok(Self {
 909                                         $(
 910                                                 $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
 911                                         ),*
 912                                 })
 913                         }
 914                 }
 915         }
 916 }
 917
 918 /// Defines a struct for a TLV stream and a similar struct using references for non-primitive types,
 919 /// implementing [`Readable`] for the former and [`Writeable`] for the latter. Useful as an
 920 /// intermediary format when reading or writing a type encoded as a TLV stream. Note that each field
 921 /// representing a TLV record has its type wrapped with an [`Option`]. A tuple consisting of a type
 922 /// and a serialization wrapper may be given in place of a type when custom serialization is
 923 /// required.
 924 ///
 925 /// [`Readable`]: crate::util::ser::Readable
 926 /// [`Writeable`]: crate::util::ser::Writeable
 927 macro_rules! tlv_stream {
 928         ($name:ident, $nameref:ident, $range:expr, {
 929                 $(($type:expr, $field:ident : $fieldty:tt)),* $(,)*
 930         }) => {
 931                 #[derive(Debug)]
 932                 pub(super) struct $name {
 933                         $(
 934                                 pub(super) $field: Option<tlv_record_type!($fieldty)>,
 935                         )*
 936                 }
 937
 938                 #[cfg_attr(test, derive(PartialEq))]
 939                 #[derive(Debug)]
 940                 pub(crate) struct $nameref<'a> {
 941                         $(
 942                                 pub(super) $field: Option<tlv_record_ref_type!($fieldty)>,
 943                         )*
 944                 }
 945
 946                 impl<'a> $crate::util::ser::Writeable for $nameref<'a> {
 947                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 948                                 encode_tlv_stream!(writer, {
 949                                         $(($type, self.$field, (option, encoding: $fieldty))),*
 950                                 });
 951                                 Ok(())
 952                         }
 953                 }
 954
 955                 impl $crate::util::ser::SeekReadable for $name {
 956                         fn read<R: $crate::io::Read + $crate::io::Seek>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 957                                 $(
 958                                         _init_tlv_field_var!($field, option);
 959                                 )*
 960                                 let rewind = |cursor: &mut R, offset: usize| {
 961                                         cursor.seek($crate::io::SeekFrom::Current(-(offset as i64))).expect("");
 962                                 };
 963                                 _decode_tlv_stream_range!(reader, $range, rewind, {
 964                                         $(($type, $field, (option, encoding: $fieldty))),*
 965                                 });
 966
 967                                 Ok(Self {
 968                                         $(
 969                                                 $field: $field
 970                                         ),*
 971                                 })
 972                         }
 973                 }
 974         }
 975 }
 976
 977 macro_rules! tlv_record_type {
 978         (($type:ty, $wrapper:ident)) => { $type };
 979         (($type:ty, $wrapper:ident, $encoder:ty)) => { $type };
 980         ($type:ty) => { $type };
 981 }
 982
 983 macro_rules! tlv_record_ref_type {
 984         (char) => { char };
 985         (u8) => { u8 };
 986         ((u16, $wrapper: ident)) => { u16 };
 987         ((u32, $wrapper: ident)) => { u32 };
 988         ((u64, $wrapper: ident)) => { u64 };
 989         (($type:ty, $wrapper:ident)) => { &'a $type };
 990         (($type:ty, $wrapper:ident, $encoder:ty)) => { $encoder };
 991         ($type:ty) => { &'a $type };
 992 }
 993
 994 #[doc(hidden)]
 995 #[macro_export]
 996 macro_rules! _impl_writeable_tlv_based_enum_common {
 997         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 998                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 999         ),* $(,)*;
1000         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
1001                 impl $crate::util::ser::Writeable for $st {
1002                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
1003                                 match self {
1004                                         $($st::$variant_name { $(ref $field),* } => {
1005                                                 let id: u8 = $variant_id;
1006                                                 id.write(writer)?;
1007                                                 $crate::write_tlv_fields!(writer, {
1008                                                         $(($type, *$field, $fieldty)),*
1009                                                 });
1010                                         }),*
1011                                         $($st::$tuple_variant_name (ref field) => {
1012                                                 let id: u8 = $tuple_variant_id;
1013                                                 id.write(writer)?;
1014                                                 field.write(writer)?;
1015                                         }),*
1016                                 }
1017                                 Ok(())
1018                         }
1019                 }
1020         }
1021 }
1022
1023 /// Implement [`Readable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and tuple
1024 /// variants stored directly.
1025 /// The format is, for example
1026 /// ```ignore
1027 /// impl_writeable_tlv_based_enum!(EnumName,
1028 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
1029 ///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, optional_vec)};
1030 ///   (2, TupleVariantA), (3, TupleVariantB),
1031 /// );
1032 /// ```
1033 /// The type is written as a single byte, followed by any variant data.
1034 /// Attempts to read an unknown type byte result in [`DecodeError::UnknownRequiredFeature`].
1035 ///
1036 /// [`Readable`]: crate::util::ser::Readable
1037 /// [`Writeable`]: crate::util::ser::Writeable
1038 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1039 #[macro_export]
1040 macro_rules! impl_writeable_tlv_based_enum {
1041         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1042                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1043         ),* $(,)*;
1044         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
1045                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1046                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1047                         $(($tuple_variant_id, $tuple_variant_name)),*);
1048
1049                 impl $crate::util::ser::Readable for $st {
1050                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
1051                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1052                                 match id {
1053                                         $($variant_id => {
1054                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1055                                                 // in the same function body. Instead, we define a closure and call it.
1056                                                 let mut f = || {
1057                                                         $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
1058                                                                 $(($type, $field, $fieldty)),*
1059                                                         });
1060                                                         Ok($st::$variant_name {
1061                                                                 $(
1062                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1063                                                                 ),*
1064                                                         })
1065                                                 };
1066                                                 f()
1067                                         }),*
1068                                         $($tuple_variant_id => {
1069                                                 Ok($st::$tuple_variant_name($crate::util::ser::Readable::read(reader)?))
1070                                         }),*
1071                                         _ => {
1072                                                 Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature)
1073                                         },
1074                                 }
1075                         }
1076                 }
1077         }
1078 }
1079
1080 /// Implement [`MaybeReadable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and
1081 /// tuple variants stored directly.
1082 ///
1083 /// This is largely identical to [`impl_writeable_tlv_based_enum`], except that odd variants will
1084 /// return `Ok(None)` instead of `Err(`[`DecodeError::UnknownRequiredFeature`]`)`. It should generally be preferred
1085 /// when [`MaybeReadable`] is practical instead of just [`Readable`] as it provides an upgrade path for
1086 /// new variants to be added which are simply ignored by existing clients.
1087 ///
1088 /// Note that only struct and unit variants (not tuple variants) will support downgrading, thus any
1089 /// new odd variants MUST be non-tuple (i.e. described using `$variant_id` and `$variant_name` not
1090 /// `$tuple_variant_id` and `$tuple_variant_name`).
1091 ///
1092 /// [`MaybeReadable`]: crate::util::ser::MaybeReadable
1093 /// [`Writeable`]: crate::util::ser::Writeable
1094 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1095 /// [`Readable`]: crate::util::ser::Readable
1096 #[macro_export]
1097 macro_rules! impl_writeable_tlv_based_enum_upgradable {
1098         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1099                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1100         ),* $(,)*
1101         $(;
1102         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
1103                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1104                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1105                         $($(($tuple_variant_id, $tuple_variant_name)),*)*);
1106
1107                 impl $crate::util::ser::MaybeReadable for $st {
1108                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Option<Self>, $crate::ln::msgs::DecodeError> {
1109                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1110                                 match id {
1111                                         $($variant_id => {
1112                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1113                                                 // in the same function body. Instead, we define a closure and call it.
1114                                                 let mut f = || {
1115                                                         $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
1116                                                                 $(($type, $field, $fieldty)),*
1117                                                         });
1118                                                         Ok(Some($st::$variant_name {
1119                                                                 $(
1120                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1121                                                                 ),*
1122                                                         }))
1123                                                 };
1124                                                 f()
1125                                         }),*
1126                                         $($($tuple_variant_id => {
1127                                                 Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
1128                                         }),*)*
1129                                         _ if id % 2 == 1 => {
1130                                                 // Assume that a $variant_id was written, not a $tuple_variant_id, and read
1131                                                 // the length prefix and discard the correct number of bytes.
1132                                                 let tlv_len: $crate::util::ser::BigSize = $crate::util::ser::Readable::read(reader)?;
1133                                                 let mut rd = $crate::util::ser::FixedLengthReader::new(reader, tlv_len.0);
1134                                                 rd.eat_remaining().map_err(|_| $crate::ln::msgs::DecodeError::ShortRead)?;
1135                                                 Ok(None)
1136                                         },
1137                                         _ => Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature),
1138                                 }
1139                         }
1140                 }
1141         }
1142 }
1143
1144 #[cfg(test)]
1145 mod tests {
1146         #[allow(unused_imports)]
1147         use crate::prelude::*;
1148
1149         use crate::io::{self, Cursor};
1150         use crate::ln::msgs::DecodeError;
1151         use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
1152         use bitcoin::hashes::hex::FromHex;
1153         use bitcoin::secp256k1::PublicKey;
1154
1155         // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
1156         // the encoding layer in the BOLTs has no such concept, though it makes our macros easier to
1157         // work with so they're baked into the decoder. Thus, we have a few additional tests below
1158         fn tlv_reader(s: &[u8]) -> Result<(u64, u32, Option<u32>), DecodeError> {
1159                 let mut s = Cursor::new(s);
1160                 let mut a: u64 = 0;
1161                 let mut b: u32 = 0;
1162                 let mut c: Option<u32> = None;
1163                 decode_tlv_stream!(&mut s, {(2, a, required), (3, b, required), (4, c, option)});
1164                 Ok((a, b, c))
1165         }
1166
1167         #[test]
1168         fn tlv_v_short_read() {
1169                 // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
1170                 if let Err(DecodeError::ShortRead) = tlv_reader(&<Vec<u8>>::from_hex(
1171                                 concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
1172                                 ).unwrap()[..]) {
1173                 } else { panic!(); }
1174         }
1175
1176         #[test]
1177         fn tlv_types_out_of_order() {
1178                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1179                                 concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
1180                                 ).unwrap()[..]) {
1181                 } else { panic!(); }
1182                 // ...even if its some field we don't understand
1183                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1184                                 concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
1185                                 ).unwrap()[..]) {
1186                 } else { panic!(); }
1187         }
1188
1189         #[test]
1190         fn tlv_req_type_missing_or_extra() {
1191                 // It's also bad if they included even fields we don't understand
1192                 if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&<Vec<u8>>::from_hex(
1193                                 concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
1194                                 ).unwrap()[..]) {
1195                 } else { panic!(); }
1196                 // ... or if they're missing fields we need
1197                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1198                                 concat!("0100", "0208deadbeef1badbeef")
1199                                 ).unwrap()[..]) {
1200                 } else { panic!(); }
1201                 // ... even if that field is even
1202                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1203                                 concat!("0304deadbeef", "0500")
1204                                 ).unwrap()[..]) {
1205                 } else { panic!(); }
1206         }
1207
1208         #[test]
1209         fn tlv_simple_good_cases() {
1210                 assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
1211                                 concat!("0208deadbeef1badbeef", "03041bad1dea")
1212                                 ).unwrap()[..]).unwrap(),
1213                         (0xdeadbeef1badbeef, 0x1bad1dea, None));
1214                 assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
1215                                 concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
1216                                 ).unwrap()[..]).unwrap(),
1217                         (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
1218         }
1219
1220         #[derive(Debug, PartialEq)]
1221         struct TestUpgradable {
1222                 a: u32,
1223                 b: u32,
1224                 c: Option<u32>,
1225         }
1226
1227         fn upgradable_tlv_reader(s: &[u8]) -> Result<Option<TestUpgradable>, DecodeError> {
1228                 let mut s = Cursor::new(s);
1229                 let mut a = 0;
1230                 let mut b = 0;
1231                 let mut c: Option<u32> = None;
1232                 decode_tlv_stream!(&mut s, {(2, a, upgradable_required), (3, b, upgradable_required), (4, c, upgradable_option)});
1233                 Ok(Some(TestUpgradable { a, b, c, }))
1234         }
1235
1236         #[test]
1237         fn upgradable_tlv_simple_good_cases() {
1238                 assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1239                         concat!("0204deadbeef", "03041bad1dea", "0404deadbeef")
1240                 ).unwrap()[..]).unwrap(),
1241                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: Some(0xdeadbeef) }));
1242
1243                 assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1244                         concat!("0204deadbeef", "03041bad1dea")
1245                 ).unwrap()[..]).unwrap(),
1246                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: None}));
1247         }
1248
1249         #[test]
1250         fn missing_required_upgradable() {
1251                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1252                         concat!("0100", "0204deadbeef")
1253                         ).unwrap()[..]) {
1254                 } else { panic!(); }
1255                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1256                         concat!("0100", "03041bad1dea")
1257                 ).unwrap()[..]) {
1258                 } else { panic!(); }
1259         }
1260
1261         // BOLT TLV test cases
1262         fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
1263                 let mut s = Cursor::new(s);
1264                 let mut tlv1: Option<HighZeroBytesDroppedBigSize<u64>> = None;
1265                 let mut tlv2: Option<u64> = None;
1266                 let mut tlv3: Option<(PublicKey, u64, u64)> = None;
1267                 let mut tlv4: Option<u16> = None;
1268                 decode_tlv_stream!(&mut s, {(1, tlv1, option), (2, tlv2, option), (3, tlv3, option), (254, tlv4, option)});
1269                 Ok((tlv1, tlv2, tlv3, tlv4))
1270         }
1271
1272         #[test]
1273         fn bolt_tlv_bogus_stream() {
1274                 macro_rules! do_test {
1275                         ($stream: expr, $reason: ident) => {
1276                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1277                                 } else { panic!(); }
1278                         }
1279                 }
1280
1281                 // TLVs from the BOLT test cases which should not decode as either n1 or n2
1282                 do_test!(concat!("fd01"), ShortRead);
1283                 do_test!(concat!("fd0001", "00"), InvalidValue);
1284                 do_test!(concat!("fd0101"), ShortRead);
1285                 do_test!(concat!("0f", "fd"), ShortRead);
1286                 do_test!(concat!("0f", "fd26"), ShortRead);
1287                 do_test!(concat!("0f", "fd2602"), ShortRead);
1288                 do_test!(concat!("0f", "fd0001", "00"), InvalidValue);
1289                 do_test!(concat!("0f", "fd0201", "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"), ShortRead);
1290
1291                 do_test!(concat!("12", "00"), UnknownRequiredFeature);
1292                 do_test!(concat!("fd0102", "00"), UnknownRequiredFeature);
1293                 do_test!(concat!("fe01000002", "00"), UnknownRequiredFeature);
1294                 do_test!(concat!("ff0100000000000002", "00"), UnknownRequiredFeature);
1295         }
1296
1297         #[test]
1298         fn bolt_tlv_bogus_n1_stream() {
1299                 macro_rules! do_test {
1300                         ($stream: expr, $reason: ident) => {
1301                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1302                                 } else { panic!(); }
1303                         }
1304                 }
1305
1306                 // TLVs from the BOLT test cases which should not decode as n1
1307                 do_test!(concat!("01", "09", "ffffffffffffffffff"), InvalidValue);
1308                 do_test!(concat!("01", "01", "00"), InvalidValue);
1309                 do_test!(concat!("01", "02", "0001"), InvalidValue);
1310                 do_test!(concat!("01", "03", "000100"), InvalidValue);
1311                 do_test!(concat!("01", "04", "00010000"), InvalidValue);
1312                 do_test!(concat!("01", "05", "0001000000"), InvalidValue);
1313                 do_test!(concat!("01", "06", "000100000000"), InvalidValue);
1314                 do_test!(concat!("01", "07", "00010000000000"), InvalidValue);
1315                 do_test!(concat!("01", "08", "0001000000000000"), InvalidValue);
1316                 do_test!(concat!("02", "07", "01010101010101"), ShortRead);
1317                 do_test!(concat!("02", "09", "010101010101010101"), InvalidValue);
1318                 do_test!(concat!("03", "21", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb"), ShortRead);
1319                 do_test!(concat!("03", "29", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001"), ShortRead);
1320                 do_test!(concat!("03", "30", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb000000000000000100000000000001"), ShortRead);
1321                 do_test!(concat!("03", "31", "043da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"), InvalidValue);
1322                 do_test!(concat!("03", "32", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001000000000000000001"), InvalidValue);
1323                 do_test!(concat!("fd00fe", "00"), ShortRead);
1324                 do_test!(concat!("fd00fe", "01", "01"), ShortRead);
1325                 do_test!(concat!("fd00fe", "03", "010101"), InvalidValue);
1326                 do_test!(concat!("00", "00"), UnknownRequiredFeature);
1327
1328                 do_test!(concat!("02", "08", "0000000000000226", "01", "01", "2a"), InvalidValue);
1329                 do_test!(concat!("02", "08", "0000000000000231", "02", "08", "0000000000000451"), InvalidValue);
1330                 do_test!(concat!("1f", "00", "0f", "01", "2a"), InvalidValue);
1331                 do_test!(concat!("1f", "00", "1f", "01", "2a"), InvalidValue);
1332
1333                 // The last BOLT test modified to not require creating a new decoder for one trivial test.
1334                 do_test!(concat!("ffffffffffffffffff", "00", "01", "00"), InvalidValue);
1335         }
1336
1337         #[test]
1338         fn bolt_tlv_valid_n1_stream() {
1339                 macro_rules! do_test {
1340                         ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
1341                                 if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1342                                         assert_eq!(tlv1.map(|v| v.0), $tlv1);
1343                                         assert_eq!(tlv2, $tlv2);
1344                                         assert_eq!(tlv3, $tlv3);
1345                                         assert_eq!(tlv4, $tlv4);
1346                                 } else { panic!(); }
1347                         }
1348                 }
1349
1350                 do_test!(concat!(""), None, None, None, None);
1351                 do_test!(concat!("21", "00"), None, None, None, None);
1352                 do_test!(concat!("fd0201", "00"), None, None, None, None);
1353                 do_test!(concat!("fd00fd", "00"), None, None, None, None);
1354                 do_test!(concat!("fd00ff", "00"), None, None, None, None);
1355                 do_test!(concat!("fe02000001", "00"), None, None, None, None);
1356                 do_test!(concat!("ff0200000000000001", "00"), None, None, None, None);
1357
1358                 do_test!(concat!("01", "00"), Some(0), None, None, None);
1359                 do_test!(concat!("01", "01", "01"), Some(1), None, None, None);
1360                 do_test!(concat!("01", "02", "0100"), Some(256), None, None, None);
1361                 do_test!(concat!("01", "03", "010000"), Some(65536), None, None, None);
1362                 do_test!(concat!("01", "04", "01000000"), Some(16777216), None, None, None);
1363                 do_test!(concat!("01", "05", "0100000000"), Some(4294967296), None, None, None);
1364                 do_test!(concat!("01", "06", "010000000000"), Some(1099511627776), None, None, None);
1365                 do_test!(concat!("01", "07", "01000000000000"), Some(281474976710656), None, None, None);
1366                 do_test!(concat!("01", "08", "0100000000000000"), Some(72057594037927936), None, None, None);
1367                 do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
1368                 do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
1369                         None, None, Some((
1370                                 PublicKey::from_slice(&<Vec<u8>>::from_hex("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
1371                         None);
1372                 do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
1373         }
1374
1375         fn do_simple_test_tlv_write() -> Result<(), io::Error> {
1376                 let mut stream = VecWriter(Vec::new());
1377
1378                 stream.0.clear();
1379                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
1380                 assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
1381
1382                 stream.0.clear();
1383                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
1384                 assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
1385
1386                 stream.0.clear();
1387                 _encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
1388                 assert_eq!(stream.0, <Vec<u8>>::from_hex("040402abcd").unwrap());
1389
1390                 stream.0.clear();
1391                 _encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
1392                 assert_eq!(stream.0, <Vec<u8>>::from_hex("06fd00ff02abcd").unwrap());
1393
1394                 stream.0.clear();
1395                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1396                 assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
1397
1398                 stream.0.clear();
1399                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1400                 assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
1401
1402                 Ok(())
1403         }
1404
1405         #[test]
1406         fn simple_test_tlv_write() {
1407                 do_simple_test_tlv_write().unwrap();
1408         }
1409 }