_ 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 macro_rules! encode_tlv {
  11         ($stream: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
  12                 encode_tlv!($stream, $type, $field, required)
  13         };
  14         ($stream: expr, $type: expr, $field: expr, required) => {
  15                 BigSize($type).write($stream)?;
  16                 BigSize($field.serialized_length() as u64).write($stream)?;
  17                 $field.write($stream)?;
  18         };
  19         ($stream: expr, $type: expr, $field: expr, vec_type) => {
  20                 encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
  21         };
  22         ($stream: expr, $optional_type: expr, $optional_field: expr, option) => {
  23                 if let Some(ref field) = $optional_field {
  24                         BigSize($optional_type).write($stream)?;
  25                         BigSize(field.serialized_length() as u64).write($stream)?;
  26                         field.write($stream)?;
  27                 }
  28         };
  29         ($stream: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
  30                 encode_tlv!($stream, $type, $field.map(|f| $encoding(f)), option);
  31         };
  32         ($stream: expr, $type: expr, $field: expr, (option, encoding: $fieldty: ty)) => {
  33                 encode_tlv!($stream, $type, $field, option);
  34         };
  35 }
  36
  37 macro_rules! encode_tlv_stream {
  38         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => { {
  39                 #[allow(unused_imports)]
  40                 use $crate::{
  41                         ln::msgs::DecodeError,
  42                         util::ser,
  43                         util::ser::BigSize,
  44                 };
  45
  46                 $(
  47                         encode_tlv!($stream, $type, $field, $fieldty);
  48                 )*
  49
  50                 #[allow(unused_mut, unused_variables, unused_assignments)]
  51                 #[cfg(debug_assertions)]
  52                 {
  53                         let mut last_seen: Option<u64> = None;
  54                         $(
  55                                 if let Some(t) = last_seen {
  56                                         debug_assert!(t <= $type);
  57                                 }
  58                                 last_seen = Some($type);
  59                         )*
  60                 }
  61         } }
  62 }
  63
  64 macro_rules! get_varint_length_prefixed_tlv_length {
  65         ($len: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
  66                 get_varint_length_prefixed_tlv_length!($len, $type, $field, required)
  67         };
  68         ($len: expr, $type: expr, $field: expr, required) => {
  69                 BigSize($type).write(&mut $len).expect("No in-memory data may fail to serialize");
  70                 let field_len = $field.serialized_length();
  71                 BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
  72                 $len.0 += field_len;
  73         };
  74         ($len: expr, $type: expr, $field: expr, vec_type) => {
  75                 get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
  76         };
  77         ($len: expr, $optional_type: expr, $optional_field: expr, option) => {
  78                 if let Some(ref field) = $optional_field {
  79                         BigSize($optional_type).write(&mut $len).expect("No in-memory data may fail to serialize");
  80                         let field_len = field.serialized_length();
  81                         BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
  82                         $len.0 += field_len;
  83                 }
  84         };
  85 }
  86
  87 macro_rules! encode_varint_length_prefixed_tlv {
  88         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}) => { {
  89                 use $crate::util::ser::BigSize;
  90                 let len = {
  91                         #[allow(unused_mut)]
  92                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
  93                         $(
  94                                 get_varint_length_prefixed_tlv_length!(len, $type, $field, $fieldty);
  95                         )*
  96                         len.0
  97                 };
  98                 BigSize(len as u64).write($stream)?;
  99                 encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* });
 100         } }
 101 }
 102
 103 macro_rules! check_tlv_order {
 104         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 105                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always true
 106                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 107                 if invalid_order {
 108                         $field = $default.into();
 109                 }
 110         }};
 111         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required) => {{
 112                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always true
 113                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
 114                 if invalid_order {
 115                         return Err(DecodeError::InvalidValue);
 116                 }
 117         }};
 118         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
 119                 // no-op
 120         }};
 121         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, vec_type) => {{
 122                 // no-op
 123         }};
 124         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, ignorable) => {{
 125                 // no-op
 126         }};
 127         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 128                 // no-op
 129         }};
 130         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 131                 // no-op
 132         }};
 133 }
 134
 135 macro_rules! check_missing_tlv {
 136         ($last_seen_type: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
 137                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always true
 138                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 139                 if missing_req_type {
 140                         $field = $default.into();
 141                 }
 142         }};
 143         ($last_seen_type: expr, $type: expr, $field: ident, required) => {{
 144                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always true
 145                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
 146                 if missing_req_type {
 147                         return Err(DecodeError::InvalidValue);
 148                 }
 149         }};
 150         ($last_seen_type: expr, $type: expr, $field: ident, vec_type) => {{
 151                 // no-op
 152         }};
 153         ($last_seen_type: expr, $type: expr, $field: ident, option) => {{
 154                 // no-op
 155         }};
 156         ($last_seen_type: expr, $type: expr, $field: ident, ignorable) => {{
 157                 // no-op
 158         }};
 159         ($last_seen_type: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 160                 // no-op
 161         }};
 162         ($last_seen_type: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
 163                 // no-op
 164         }};
 165 }
 166
 167 macro_rules! decode_tlv {
 168         ($reader: expr, $field: ident, (default_value, $default: expr)) => {{
 169                 decode_tlv!($reader, $field, required)
 170         }};
 171         ($reader: expr, $field: ident, required) => {{
 172                 $field = $crate::util::ser::Readable::read(&mut $reader)?;
 173         }};
 174         ($reader: expr, $field: ident, vec_type) => {{
 175                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
 176                 $field = Some(f.0);
 177         }};
 178         ($reader: expr, $field: ident, option) => {{
 179                 $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
 180         }};
 181         ($reader: expr, $field: ident, ignorable) => {{
 182                 $field = $crate::util::ser::MaybeReadable::read(&mut $reader)?;
 183         }};
 184         ($reader: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
 185                 $field = Some($trait::read(&mut $reader $(, $read_arg)*)?);
 186         }};
 187         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {{
 188                 $field = {
 189                         let field: $encoding<$fieldty> = ser::Readable::read(&mut $reader)?;
 190                         Some(field.0)
 191                 };
 192         }};
 193         ($reader: expr, $field: ident, (option, encoding: $fieldty: ty)) => {{
 194                 decode_tlv!($reader, $field, option);
 195         }};
 196 }
 197
 198 // `$decode_custom_tlv` is a closure that may be optionally provided to handle custom message types.
 199 // If it is provided, it will be called with the custom type and the `FixedLengthReader` containing
 200 // the message contents. It should return `Ok(true)` if the custom message is successfully parsed,
 201 // `Ok(false)` if the message type is unknown, and `Err(DecodeError)` if parsing fails.
 202 macro_rules! decode_tlv_stream {
 203         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 204          $(, $decode_custom_tlv: expr)?) => { {
 205                 let rewind = |_, _| { unreachable!() };
 206                 use core::ops::RangeBounds;
 207                 decode_tlv_stream_range!(
 208                         $stream, .., rewind, {$(($type, $field, $fieldty)),*} $(, $decode_custom_tlv)?
 209                 );
 210         } }
 211 }
 212
 213 macro_rules! decode_tlv_stream_range {
 214         ($stream: expr, $range: expr, $rewind: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 215          $(, $decode_custom_tlv: expr)?) => { {
 216                 use $crate::ln::msgs::DecodeError;
 217                 let mut last_seen_type: Option<u64> = None;
 218                 let mut stream_ref = $stream;
 219                 'tlv_read: loop {
 220                         use $crate::util::ser;
 221
 222                         // First decode the type of this TLV:
 223                         let typ: ser::BigSize = {
 224                                 // We track whether any bytes were read during the consensus_decode call to
 225                                 // determine whether we should break or return ShortRead if we get an
 226                                 // UnexpectedEof. This should in every case be largely cosmetic, but its nice to
 227                                 // pass the TLV test vectors exactly, which requre this distinction.
 228                                 let mut tracking_reader = ser::ReadTrackingReader::new(&mut stream_ref);
 229                                 match <$crate::util::ser::BigSize as $crate::util::ser::Readable>::read(&mut tracking_reader) {
 230                                         Err(DecodeError::ShortRead) => {
 231                                                 if !tracking_reader.have_read {
 232                                                         break 'tlv_read;
 233                                                 } else {
 234                                                         return Err(DecodeError::ShortRead);
 235                                                 }
 236                                         },
 237                                         Err(e) => return Err(e),
 238                                         Ok(t) => if $range.contains(&t.0) { t } else {
 239                                                 drop(tracking_reader);
 240
 241                                                 // Assumes the type id is minimally encoded, which is enforced on read.
 242                                                 use $crate::util::ser::Writeable;
 243                                                 let bytes_read = t.serialized_length();
 244                                                 $rewind(stream_ref, bytes_read);
 245                                                 break 'tlv_read;
 246                                         },
 247                                 }
 248                         };
 249
 250                         // Types must be unique and monotonically increasing:
 251                         match last_seen_type {
 252                                 Some(t) if typ.0 <= t => {
 253                                         return Err(DecodeError::InvalidValue);
 254                                 },
 255                                 _ => {},
 256                         }
 257                         // As we read types, make sure we hit every required type:
 258                         $({
 259                                 check_tlv_order!(last_seen_type, typ, $type, $field, $fieldty);
 260                         })*
 261                         last_seen_type = Some(typ.0);
 262
 263                         // Finally, read the length and value itself:
 264                         let length: ser::BigSize = $crate::util::ser::Readable::read(&mut stream_ref)?;
 265                         let mut s = ser::FixedLengthReader::new(&mut stream_ref, length.0);
 266                         match typ.0 {
 267                                 $($type => {
 268                                         decode_tlv!(s, $field, $fieldty);
 269                                         if s.bytes_remain() {
 270                                                 s.eat_remaining()?; // Return ShortRead if there's actually not enough bytes
 271                                                 return Err(DecodeError::InvalidValue);
 272                                         }
 273                                 },)*
 274                                 t => {
 275                                         $(
 276                                                 if $decode_custom_tlv(t, &mut s)? {
 277                                                         // If a custom TLV was successfully read (i.e. decode_custom_tlv returns true),
 278                                                         // continue to the next TLV read.
 279                                                         s.eat_remaining()?;
 280                                                         continue 'tlv_read;
 281                                                 }
 282                                         )?
 283                                         if t % 2 == 0 {
 284                                                 return Err(DecodeError::UnknownRequiredFeature);
 285                                         }
 286                                 }
 287                         }
 288                         s.eat_remaining()?;
 289                 }
 290                 // Make sure we got to each required type after we've read every TLV:
 291                 $({
 292                         check_missing_tlv!(last_seen_type, $type, $field, $fieldty);
 293                 })*
 294         } }
 295 }
 296
 297 macro_rules! impl_writeable_msg {
 298         ($st:ident, {$($field:ident),* $(,)*}, {$(($type: expr, $tlvfield: ident, $fieldty: tt)),* $(,)*}) => {
 299                 impl $crate::util::ser::Writeable for $st {
 300                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 301                                 $( self.$field.write(w)?; )*
 302                                 encode_tlv_stream!(w, {$(($type, self.$tlvfield, $fieldty)),*});
 303                                 Ok(())
 304                         }
 305                 }
 306                 impl $crate::util::ser::Readable for $st {
 307                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 308                                 $(let $field = $crate::util::ser::Readable::read(r)?;)*
 309                                 $(init_tlv_field_var!($tlvfield, $fieldty);)*
 310                                 decode_tlv_stream!(r, {$(($type, $tlvfield, $fieldty)),*});
 311                                 Ok(Self {
 312                                         $($field),*,
 313                                         $($tlvfield),*
 314                                 })
 315                         }
 316                 }
 317         }
 318 }
 319
 320 macro_rules! impl_writeable {
 321         ($st:ident, {$($field:ident),*}) => {
 322                 impl $crate::util::ser::Writeable for $st {
 323                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
 324                                 $( self.$field.write(w)?; )*
 325                                 Ok(())
 326                         }
 327
 328                         #[inline]
 329                         fn serialized_length(&self) -> usize {
 330                                 let mut len_calc = 0;
 331                                 $( len_calc += self.$field.serialized_length(); )*
 332                                 return len_calc;
 333                         }
 334                 }
 335
 336                 impl $crate::util::ser::Readable for $st {
 337                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 338                                 Ok(Self {
 339                                         $($field: $crate::util::ser::Readable::read(r)?),*
 340                                 })
 341                         }
 342                 }
 343         }
 344 }
 345
 346 /// Write out two bytes to indicate the version of an object.
 347 /// $this_version represents a unique version of a type. Incremented whenever the type's
 348 ///               serialization format has changed or has a new interpretation. Used by a type's
 349 ///               reader to determine how to interpret fields or if it can understand a serialized
 350 ///               object.
 351 /// $min_version_that_can_read_this is the minimum reader version which can understand this
 352 ///                                 serialized object. Previous versions will simply err with a
 353 ///                                 DecodeError::UnknownVersion.
 354 ///
 355 /// Updates to either $this_version or $min_version_that_can_read_this should be included in
 356 /// release notes.
 357 ///
 358 /// Both version fields can be specific to this type of object.
 359 macro_rules! write_ver_prefix {
 360         ($stream: expr, $this_version: expr, $min_version_that_can_read_this: expr) => {
 361                 $stream.write_all(&[$this_version; 1])?;
 362                 $stream.write_all(&[$min_version_that_can_read_this; 1])?;
 363         }
 364 }
 365
 366 /// Writes out a suffix to an object which contains potentially backwards-compatible, optional
 367 /// fields which old nodes can happily ignore.
 368 ///
 369 /// It is written out in TLV format and, as with all TLV fields, unknown even fields cause a
 370 /// DecodeError::UnknownRequiredFeature error, with unknown odd fields ignored.
 371 ///
 372 /// This is the preferred method of adding new fields that old nodes can ignore and still function
 373 /// correctly.
 374 macro_rules! write_tlv_fields {
 375         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
 376                 encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*})
 377         }
 378 }
 379
 380 /// Reads a prefix added by write_ver_prefix!(), above. Takes the current version of the
 381 /// serialization logic for this object. This is compared against the
 382 /// $min_version_that_can_read_this added by write_ver_prefix!().
 383 macro_rules! read_ver_prefix {
 384         ($stream: expr, $this_version: expr) => { {
 385                 let ver: u8 = Readable::read($stream)?;
 386                 let min_ver: u8 = Readable::read($stream)?;
 387                 if min_ver > $this_version {
 388                         return Err(DecodeError::UnknownVersion);
 389                 }
 390                 ver
 391         } }
 392 }
 393
 394 /// Reads a suffix added by write_tlv_fields.
 395 macro_rules! read_tlv_fields {
 396         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => { {
 397                 let tlv_len: $crate::util::ser::BigSize = $crate::util::ser::Readable::read($stream)?;
 398                 let mut rd = $crate::util::ser::FixedLengthReader::new($stream, tlv_len.0);
 399                 decode_tlv_stream!(&mut rd, {$(($type, $field, $fieldty)),*});
 400                 rd.eat_remaining().map_err(|_| $crate::ln::msgs::DecodeError::ShortRead)?;
 401         } }
 402 }
 403
 404 macro_rules! init_tlv_based_struct_field {
 405         ($field: ident, (default_value, $default: expr)) => {
 406                 $field.0.unwrap()
 407         };
 408         ($field: ident, option) => {
 409                 $field
 410         };
 411         ($field: ident, required) => {
 412                 $field.0.unwrap()
 413         };
 414         ($field: ident, vec_type) => {
 415                 $field.unwrap()
 416         };
 417 }
 418
 419 macro_rules! init_tlv_field_var {
 420         ($field: ident, (default_value, $default: expr)) => {
 421                 let mut $field = $crate::util::ser::OptionDeserWrapper(None);
 422         };
 423         ($field: ident, required) => {
 424                 let mut $field = $crate::util::ser::OptionDeserWrapper(None);
 425         };
 426         ($field: ident, vec_type) => {
 427                 let mut $field = Some(Vec::new());
 428         };
 429         ($field: ident, option) => {
 430                 let mut $field = None;
 431         };
 432 }
 433
 434 macro_rules! init_and_read_tlv_fields {
 435         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 436                 $(
 437                         init_tlv_field_var!($field, $fieldty);
 438                 )*
 439
 440                 read_tlv_fields!($reader, {
 441                         $(($type, $field, $fieldty)),*
 442                 });
 443         }
 444 }
 445
 446 /// Implements Readable/Writeable for a struct storing it as a set of TLVs
 447 /// If $fieldty is `required`, then $field is a required field that is not an Option nor a Vec.
 448 /// If $fieldty is `option`, then $field is optional field.
 449 /// if $fieldty is `vec_type`, then $field is a Vec, which needs to have its individual elements
 450 /// serialized.
 451 macro_rules! impl_writeable_tlv_based {
 452         ($st: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
 453                 impl $crate::util::ser::Writeable for $st {
 454                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 455                                 write_tlv_fields!(writer, {
 456                                         $(($type, self.$field, $fieldty)),*
 457                                 });
 458                                 Ok(())
 459                         }
 460
 461                         #[inline]
 462                         fn serialized_length(&self) -> usize {
 463                                 use $crate::util::ser::BigSize;
 464                                 let len = {
 465                                         #[allow(unused_mut)]
 466                                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
 467                                         $(
 468                                                 get_varint_length_prefixed_tlv_length!(len, $type, self.$field, $fieldty);
 469                                         )*
 470                                         len.0
 471                                 };
 472                                 let mut len_calc = $crate::util::ser::LengthCalculatingWriter(0);
 473                                 BigSize(len as u64).write(&mut len_calc).expect("No in-memory data may fail to serialize");
 474                                 len + len_calc.0
 475                         }
 476                 }
 477
 478                 impl $crate::util::ser::Readable for $st {
 479                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 480                                 init_and_read_tlv_fields!(reader, {
 481                                         $(($type, $field, $fieldty)),*
 482                                 });
 483                                 Ok(Self {
 484                                         $(
 485                                                 $field: init_tlv_based_struct_field!($field, $fieldty)
 486                                         ),*
 487                                 })
 488                         }
 489                 }
 490         }
 491 }
 492
 493 /// Defines a struct for a TLV stream and a similar struct using references for non-primitive types,
 494 /// implementing [`Readable`] for the former and [`Writeable`] for the latter. Useful as an
 495 /// intermediary format when reading or writing a type encoded as a TLV stream. Note that each field
 496 /// representing a TLV record has its type wrapped with an [`Option`]. A tuple consisting of a type
 497 /// and a serialization wrapper may be given in place of a type when custom serialization is
 498 /// required.
 499 ///
 500 /// [`Readable`]: crate::util::ser::Readable
 501 /// [`Writeable`]: crate::util::ser::Writeable
 502 macro_rules! tlv_stream {
 503         ($name:ident, $nameref:ident, $range:expr, {
 504                 $(($type:expr, $field:ident : $fieldty:tt)),* $(,)*
 505         }) => {
 506                 #[derive(Debug)]
 507                 pub(crate) struct $name {
 508                         $(
 509                                 $field: Option<tlv_record_type!($fieldty)>,
 510                         )*
 511                 }
 512
 513                 pub(crate) struct $nameref<'a> {
 514                         $(
 515                                 pub(crate) $field: Option<tlv_record_ref_type!($fieldty)>,
 516                         )*
 517                 }
 518
 519                 impl<'a> $crate::util::ser::Writeable for $nameref<'a> {
 520                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 521                                 encode_tlv_stream!(writer, {
 522                                         $(($type, self.$field, (option, encoding: $fieldty))),*
 523                                 });
 524                                 Ok(())
 525                         }
 526                 }
 527
 528                 impl $crate::util::ser::SeekReadable for $name {
 529                         fn read<R: $crate::io::Read + $crate::io::Seek>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 530                                 $(
 531                                         init_tlv_field_var!($field, option);
 532                                 )*
 533                                 let rewind = |cursor: &mut R, offset: usize| {
 534                                         cursor.seek($crate::io::SeekFrom::Current(-(offset as i64))).expect("");
 535                                 };
 536                                 decode_tlv_stream_range!(reader, $range, rewind, {
 537                                         $(($type, $field, (option, encoding: $fieldty))),*
 538                                 });
 539
 540                                 Ok(Self {
 541                                         $(
 542                                                 $field: $field
 543                                         ),*
 544                                 })
 545                         }
 546                 }
 547         }
 548 }
 549
 550 macro_rules! tlv_record_type {
 551         (($type:ty, $wrapper:ident)) => { $type };
 552         ($type:ty) => { $type };
 553 }
 554
 555 macro_rules! tlv_record_ref_type {
 556         (char) => { char };
 557         (u8) => { u8 };
 558         ((u16, $wrapper: ident)) => { u16 };
 559         ((u32, $wrapper: ident)) => { u32 };
 560         ((u64, $wrapper: ident)) => { u64 };
 561         (($type:ty, $wrapper:ident)) => { &'a $type };
 562         ($type:ty) => { &'a $type };
 563 }
 564
 565 macro_rules! _impl_writeable_tlv_based_enum_common {
 566         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 567                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 568         ),* $(,)*;
 569         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
 570                 impl $crate::util::ser::Writeable for $st {
 571                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
 572                                 match self {
 573                                         $($st::$variant_name { $(ref $field),* } => {
 574                                                 let id: u8 = $variant_id;
 575                                                 id.write(writer)?;
 576                                                 write_tlv_fields!(writer, {
 577                                                         $(($type, *$field, $fieldty)),*
 578                                                 });
 579                                         }),*
 580                                         $($st::$tuple_variant_name (ref field) => {
 581                                                 let id: u8 = $tuple_variant_id;
 582                                                 id.write(writer)?;
 583                                                 field.write(writer)?;
 584                                         }),*
 585                                 }
 586                                 Ok(())
 587                         }
 588                 }
 589         }
 590 }
 591
 592 /// Implement MaybeReadable and Writeable for an enum, with struct variants stored as TLVs and
 593 /// tuple variants stored directly.
 594 ///
 595 /// This is largely identical to `impl_writeable_tlv_based_enum`, except that odd variants will
 596 /// return `Ok(None)` instead of `Err(UnknownRequiredFeature)`. It should generally be preferred
 597 /// when `MaybeReadable` is practical instead of just `Readable` as it provides an upgrade path for
 598 /// new variants to be added which are simply ignored by existing clients.
 599 macro_rules! impl_writeable_tlv_based_enum_upgradable {
 600         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 601                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 602         ),* $(,)*
 603         $(;
 604         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
 605                 _impl_writeable_tlv_based_enum_common!($st,
 606                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
 607                         $($(($tuple_variant_id, $tuple_variant_name)),*)*);
 608
 609                 impl $crate::util::ser::MaybeReadable for $st {
 610                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Option<Self>, $crate::ln::msgs::DecodeError> {
 611                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
 612                                 match id {
 613                                         $($variant_id => {
 614                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
 615                                                 // in the same function body. Instead, we define a closure and call it.
 616                                                 let f = || {
 617                                                         init_and_read_tlv_fields!(reader, {
 618                                                                 $(($type, $field, $fieldty)),*
 619                                                         });
 620                                                         Ok(Some($st::$variant_name {
 621                                                                 $(
 622                                                                         $field: init_tlv_based_struct_field!($field, $fieldty)
 623                                                                 ),*
 624                                                         }))
 625                                                 };
 626                                                 f()
 627                                         }),*
 628                                         $($($tuple_variant_id => {
 629                                                 Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
 630                                         }),*)*
 631                                         _ if id % 2 == 1 => Ok(None),
 632                                         _ => Err(DecodeError::UnknownRequiredFeature),
 633                                 }
 634                         }
 635                 }
 636
 637         }
 638 }
 639
 640 /// Implement Readable and Writeable for an enum, with struct variants stored as TLVs and tuple
 641 /// variants stored directly.
 642 /// The format is, for example
 643 /// impl_writeable_tlv_based_enum!(EnumName,
 644 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
 645 ///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, vec_type)};
 646 ///   (2, TupleVariantA), (3, TupleVariantB),
 647 /// );
 648 /// The type is written as a single byte, followed by any variant data.
 649 /// Attempts to read an unknown type byte result in DecodeError::UnknownRequiredFeature.
 650 macro_rules! impl_writeable_tlv_based_enum {
 651         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
 652                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
 653         ),* $(,)*;
 654         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
 655                 _impl_writeable_tlv_based_enum_common!($st,
 656                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
 657                         $(($tuple_variant_id, $tuple_variant_name)),*);
 658
 659                 impl $crate::util::ser::Readable for $st {
 660                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
 661                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
 662                                 match id {
 663                                         $($variant_id => {
 664                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
 665                                                 // in the same function body. Instead, we define a closure and call it.
 666                                                 let f = || {
 667                                                         init_and_read_tlv_fields!(reader, {
 668                                                                 $(($type, $field, $fieldty)),*
 669                                                         });
 670                                                         Ok($st::$variant_name {
 671                                                                 $(
 672                                                                         $field: init_tlv_based_struct_field!($field, $fieldty)
 673                                                                 ),*
 674                                                         })
 675                                                 };
 676                                                 f()
 677                                         }),*
 678                                         $($tuple_variant_id => {
 679                                                 Ok($st::$tuple_variant_name(Readable::read(reader)?))
 680                                         }),*
 681                                         _ => {
 682                                                 Err(DecodeError::UnknownRequiredFeature)
 683                                         },
 684                                 }
 685                         }
 686                 }
 687         }
 688 }
 689
 690 #[cfg(test)]
 691 mod tests {
 692         use crate::io::{self, Cursor};
 693         use crate::prelude::*;
 694         use crate::ln::msgs::DecodeError;
 695         use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
 696         use bitcoin::secp256k1::PublicKey;
 697
 698         // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
 699         // the encoding layer in the BOLTs has no such concept, though it makes our macros easier to
 700         // work with so they're baked into the decoder. Thus, we have a few additional tests below
 701         fn tlv_reader(s: &[u8]) -> Result<(u64, u32, Option<u32>), DecodeError> {
 702                 let mut s = Cursor::new(s);
 703                 let mut a: u64 = 0;
 704                 let mut b: u32 = 0;
 705                 let mut c: Option<u32> = None;
 706                 decode_tlv_stream!(&mut s, {(2, a, required), (3, b, required), (4, c, option)});
 707                 Ok((a, b, c))
 708         }
 709
 710         #[test]
 711         fn tlv_v_short_read() {
 712                 // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
 713                 if let Err(DecodeError::ShortRead) = tlv_reader(&::hex::decode(
 714                                 concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
 715                                 ).unwrap()[..]) {
 716                 } else { panic!(); }
 717         }
 718
 719         #[test]
 720         fn tlv_types_out_of_order() {
 721                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
 722                                 concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
 723                                 ).unwrap()[..]) {
 724                 } else { panic!(); }
 725                 // ...even if its some field we don't understand
 726                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
 727                                 concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
 728                                 ).unwrap()[..]) {
 729                 } else { panic!(); }
 730         }
 731
 732         #[test]
 733         fn tlv_req_type_missing_or_extra() {
 734                 // It's also bad if they included even fields we don't understand
 735                 if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&::hex::decode(
 736                                 concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
 737                                 ).unwrap()[..]) {
 738                 } else { panic!(); }
 739                 // ... or if they're missing fields we need
 740                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
 741                                 concat!("0100", "0208deadbeef1badbeef")
 742                                 ).unwrap()[..]) {
 743                 } else { panic!(); }
 744                 // ... even if that field is even
 745                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
 746                                 concat!("0304deadbeef", "0500")
 747                                 ).unwrap()[..]) {
 748                 } else { panic!(); }
 749         }
 750
 751         #[test]
 752         fn tlv_simple_good_cases() {
 753                 assert_eq!(tlv_reader(&::hex::decode(
 754                                 concat!("0208deadbeef1badbeef", "03041bad1dea")
 755                                 ).unwrap()[..]).unwrap(),
 756                         (0xdeadbeef1badbeef, 0x1bad1dea, None));
 757                 assert_eq!(tlv_reader(&::hex::decode(
 758                                 concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
 759                                 ).unwrap()[..]).unwrap(),
 760                         (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
 761         }
 762
 763         // BOLT TLV test cases
 764         fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
 765                 let mut s = Cursor::new(s);
 766                 let mut tlv1: Option<HighZeroBytesDroppedBigSize<u64>> = None;
 767                 let mut tlv2: Option<u64> = None;
 768                 let mut tlv3: Option<(PublicKey, u64, u64)> = None;
 769                 let mut tlv4: Option<u16> = None;
 770                 decode_tlv_stream!(&mut s, {(1, tlv1, option), (2, tlv2, option), (3, tlv3, option), (254, tlv4, option)});
 771                 Ok((tlv1, tlv2, tlv3, tlv4))
 772         }
 773
 774         #[test]
 775         fn bolt_tlv_bogus_stream() {
 776                 macro_rules! do_test {
 777                         ($stream: expr, $reason: ident) => {
 778                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
 779                                 } else { panic!(); }
 780                         }
 781                 }
 782
 783                 // TLVs from the BOLT test cases which should not decode as either n1 or n2
 784                 do_test!(concat!("fd01"), ShortRead);
 785                 do_test!(concat!("fd0001", "00"), InvalidValue);
 786                 do_test!(concat!("fd0101"), ShortRead);
 787                 do_test!(concat!("0f", "fd"), ShortRead);
 788                 do_test!(concat!("0f", "fd26"), ShortRead);
 789                 do_test!(concat!("0f", "fd2602"), ShortRead);
 790                 do_test!(concat!("0f", "fd0001", "00"), InvalidValue);
 791                 do_test!(concat!("0f", "fd0201", "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"), ShortRead);
 792
 793                 do_test!(concat!("12", "00"), UnknownRequiredFeature);
 794                 do_test!(concat!("fd0102", "00"), UnknownRequiredFeature);
 795                 do_test!(concat!("fe01000002", "00"), UnknownRequiredFeature);
 796                 do_test!(concat!("ff0100000000000002", "00"), UnknownRequiredFeature);
 797         }
 798
 799         #[test]
 800         fn bolt_tlv_bogus_n1_stream() {
 801                 macro_rules! do_test {
 802                         ($stream: expr, $reason: ident) => {
 803                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
 804                                 } else { panic!(); }
 805                         }
 806                 }
 807
 808                 // TLVs from the BOLT test cases which should not decode as n1
 809                 do_test!(concat!("01", "09", "ffffffffffffffffff"), InvalidValue);
 810                 do_test!(concat!("01", "01", "00"), InvalidValue);
 811                 do_test!(concat!("01", "02", "0001"), InvalidValue);
 812                 do_test!(concat!("01", "03", "000100"), InvalidValue);
 813                 do_test!(concat!("01", "04", "00010000"), InvalidValue);
 814                 do_test!(concat!("01", "05", "0001000000"), InvalidValue);
 815                 do_test!(concat!("01", "06", "000100000000"), InvalidValue);
 816                 do_test!(concat!("01", "07", "00010000000000"), InvalidValue);
 817                 do_test!(concat!("01", "08", "0001000000000000"), InvalidValue);
 818                 do_test!(concat!("02", "07", "01010101010101"), ShortRead);
 819                 do_test!(concat!("02", "09", "010101010101010101"), InvalidValue);
 820                 do_test!(concat!("03", "21", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb"), ShortRead);
 821                 do_test!(concat!("03", "29", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001"), ShortRead);
 822                 do_test!(concat!("03", "30", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb000000000000000100000000000001"), ShortRead);
 823                 do_test!(concat!("03", "31", "043da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"), InvalidValue);
 824                 do_test!(concat!("03", "32", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001000000000000000001"), InvalidValue);
 825                 do_test!(concat!("fd00fe", "00"), ShortRead);
 826                 do_test!(concat!("fd00fe", "01", "01"), ShortRead);
 827                 do_test!(concat!("fd00fe", "03", "010101"), InvalidValue);
 828                 do_test!(concat!("00", "00"), UnknownRequiredFeature);
 829
 830                 do_test!(concat!("02", "08", "0000000000000226", "01", "01", "2a"), InvalidValue);
 831                 do_test!(concat!("02", "08", "0000000000000231", "02", "08", "0000000000000451"), InvalidValue);
 832                 do_test!(concat!("1f", "00", "0f", "01", "2a"), InvalidValue);
 833                 do_test!(concat!("1f", "00", "1f", "01", "2a"), InvalidValue);
 834
 835                 // The last BOLT test modified to not require creating a new decoder for one trivial test.
 836                 do_test!(concat!("ffffffffffffffffff", "00", "01", "00"), InvalidValue);
 837         }
 838
 839         #[test]
 840         fn bolt_tlv_valid_n1_stream() {
 841                 macro_rules! do_test {
 842                         ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
 843                                 if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
 844                                         assert_eq!(tlv1.map(|v| v.0), $tlv1);
 845                                         assert_eq!(tlv2, $tlv2);
 846                                         assert_eq!(tlv3, $tlv3);
 847                                         assert_eq!(tlv4, $tlv4);
 848                                 } else { panic!(); }
 849                         }
 850                 }
 851
 852                 do_test!(concat!(""), None, None, None, None);
 853                 do_test!(concat!("21", "00"), None, None, None, None);
 854                 do_test!(concat!("fd0201", "00"), None, None, None, None);
 855                 do_test!(concat!("fd00fd", "00"), None, None, None, None);
 856                 do_test!(concat!("fd00ff", "00"), None, None, None, None);
 857                 do_test!(concat!("fe02000001", "00"), None, None, None, None);
 858                 do_test!(concat!("ff0200000000000001", "00"), None, None, None, None);
 859
 860                 do_test!(concat!("01", "00"), Some(0), None, None, None);
 861                 do_test!(concat!("01", "01", "01"), Some(1), None, None, None);
 862                 do_test!(concat!("01", "02", "0100"), Some(256), None, None, None);
 863                 do_test!(concat!("01", "03", "010000"), Some(65536), None, None, None);
 864                 do_test!(concat!("01", "04", "01000000"), Some(16777216), None, None, None);
 865                 do_test!(concat!("01", "05", "0100000000"), Some(4294967296), None, None, None);
 866                 do_test!(concat!("01", "06", "010000000000"), Some(1099511627776), None, None, None);
 867                 do_test!(concat!("01", "07", "01000000000000"), Some(281474976710656), None, None, None);
 868                 do_test!(concat!("01", "08", "0100000000000000"), Some(72057594037927936), None, None, None);
 869                 do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
 870                 do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
 871                         None, None, Some((
 872                                 PublicKey::from_slice(&::hex::decode("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
 873                         None);
 874                 do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
 875         }
 876
 877         fn do_simple_test_tlv_write() -> Result<(), io::Error> {
 878                 let mut stream = VecWriter(Vec::new());
 879
 880                 stream.0.clear();
 881                 encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
 882                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
 883
 884                 stream.0.clear();
 885                 encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
 886                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
 887
 888                 stream.0.clear();
 889                 encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
 890                 assert_eq!(stream.0, ::hex::decode("040402abcd").unwrap());
 891
 892                 stream.0.clear();
 893                 encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
 894                 assert_eq!(stream.0, ::hex::decode("06fd00ff02abcd").unwrap());
 895
 896                 stream.0.clear();
 897                 encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
 898                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
 899
 900                 stream.0.clear();
 901                 encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
 902                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
 903
 904                 Ok(())
 905         }
 906
 907         #[test]
 908         fn simple_test_tlv_write() {
 909                 do_simple_test_tlv_write().unwrap();
 910         }
 911 }