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