]> git.bitcoin.ninja Git - rust-lightning/blob - lightning/src/util/ser_macros.rs
Limit TLV stream decoding to type ranges
[rust-lightning] / 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 /// Implements Readable/Writeable for a struct storing it as a set of TLVs
435 /// If $fieldty is `required`, then $field is a required field that is not an Option nor a Vec.
436 /// If $fieldty is `option`, then $field is optional field.
437 /// if $fieldty is `vec_type`, then $field is a Vec, which needs to have its individual elements
438 /// serialized.
439 macro_rules! impl_writeable_tlv_based {
440         ($st: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
441                 impl $crate::util::ser::Writeable for $st {
442                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
443                                 write_tlv_fields!(writer, {
444                                         $(($type, self.$field, $fieldty)),*
445                                 });
446                                 Ok(())
447                         }
448
449                         #[inline]
450                         fn serialized_length(&self) -> usize {
451                                 use $crate::util::ser::BigSize;
452                                 let len = {
453                                         #[allow(unused_mut)]
454                                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
455                                         $(
456                                                 get_varint_length_prefixed_tlv_length!(len, $type, self.$field, $fieldty);
457                                         )*
458                                         len.0
459                                 };
460                                 let mut len_calc = $crate::util::ser::LengthCalculatingWriter(0);
461                                 BigSize(len as u64).write(&mut len_calc).expect("No in-memory data may fail to serialize");
462                                 len + len_calc.0
463                         }
464                 }
465
466                 impl $crate::util::ser::Readable for $st {
467                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
468                                 $(
469                                         init_tlv_field_var!($field, $fieldty);
470                                 )*
471                                 read_tlv_fields!(reader, {
472                                         $(($type, $field, $fieldty)),*
473                                 });
474                                 Ok(Self {
475                                         $(
476                                                 $field: init_tlv_based_struct_field!($field, $fieldty)
477                                         ),*
478                                 })
479                         }
480                 }
481         }
482 }
483
484 /// Defines a struct for a TLV stream and a similar struct using references for non-primitive types,
485 /// implementing [`Readable`] for the former and [`Writeable`] for the latter. Useful as an
486 /// intermediary format when reading or writing a type encoded as a TLV stream. Note that each field
487 /// representing a TLV record has its type wrapped with an [`Option`]. A tuple consisting of a type
488 /// and a serialization wrapper may be given in place of a type when custom serialization is
489 /// required.
490 ///
491 /// [`Readable`]: crate::util::ser::Readable
492 /// [`Writeable`]: crate::util::ser::Writeable
493 macro_rules! tlv_stream {
494         ($name:ident, $nameref:ident, $range:expr, {
495                 $(($type:expr, $field:ident : $fieldty:tt)),* $(,)*
496         }) => {
497                 #[derive(Debug)]
498                 pub(crate) struct $name {
499                         $(
500                                 $field: Option<tlv_record_type!($fieldty)>,
501                         )*
502                 }
503
504                 pub(crate) struct $nameref<'a> {
505                         $(
506                                 pub(crate) $field: Option<tlv_record_ref_type!($fieldty)>,
507                         )*
508                 }
509
510                 impl<'a> $crate::util::ser::Writeable for $nameref<'a> {
511                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
512                                 encode_tlv_stream!(writer, {
513                                         $(($type, self.$field, (option, encoding: $fieldty))),*
514                                 });
515                                 Ok(())
516                         }
517                 }
518
519                 impl $crate::util::ser::SeekReadable for $name {
520                         fn read<R: $crate::io::Read + $crate::io::Seek>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
521                                 $(
522                                         init_tlv_field_var!($field, option);
523                                 )*
524                                 let rewind = |cursor: &mut R, offset: usize| {
525                                         cursor.seek($crate::io::SeekFrom::Current(-(offset as i64))).expect("");
526                                 };
527                                 decode_tlv_stream_range!(reader, $range, rewind, {
528                                         $(($type, $field, (option, encoding: $fieldty))),*
529                                 });
530
531                                 Ok(Self {
532                                         $(
533                                                 $field: $field
534                                         ),*
535                                 })
536                         }
537                 }
538         }
539 }
540
541 macro_rules! tlv_record_type {
542         (($type:ty, $wrapper:ident)) => { $type };
543         ($type:ty) => { $type };
544 }
545
546 macro_rules! tlv_record_ref_type {
547         (char) => { char };
548         (u8) => { u8 };
549         ((u16, $wrapper: ident)) => { u16 };
550         ((u32, $wrapper: ident)) => { u32 };
551         ((u64, $wrapper: ident)) => { u64 };
552         (($type:ty, $wrapper:ident)) => { &'a $type };
553         ($type:ty) => { &'a $type };
554 }
555
556 macro_rules! _impl_writeable_tlv_based_enum_common {
557         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
558                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
559         ),* $(,)*;
560         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
561                 impl $crate::util::ser::Writeable for $st {
562                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
563                                 match self {
564                                         $($st::$variant_name { $(ref $field),* } => {
565                                                 let id: u8 = $variant_id;
566                                                 id.write(writer)?;
567                                                 write_tlv_fields!(writer, {
568                                                         $(($type, *$field, $fieldty)),*
569                                                 });
570                                         }),*
571                                         $($st::$tuple_variant_name (ref field) => {
572                                                 let id: u8 = $tuple_variant_id;
573                                                 id.write(writer)?;
574                                                 field.write(writer)?;
575                                         }),*
576                                 }
577                                 Ok(())
578                         }
579                 }
580         }
581 }
582
583 /// Implement MaybeReadable and Writeable for an enum, with struct variants stored as TLVs and
584 /// tuple variants stored directly.
585 ///
586 /// This is largely identical to `impl_writeable_tlv_based_enum`, except that odd variants will
587 /// return `Ok(None)` instead of `Err(UnknownRequiredFeature)`. It should generally be preferred
588 /// when `MaybeReadable` is practical instead of just `Readable` as it provides an upgrade path for
589 /// new variants to be added which are simply ignored by existing clients.
590 macro_rules! impl_writeable_tlv_based_enum_upgradable {
591         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
592                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
593         ),* $(,)*
594         $(;
595         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
596                 _impl_writeable_tlv_based_enum_common!($st,
597                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
598                         $($(($tuple_variant_id, $tuple_variant_name)),*)*);
599
600                 impl $crate::util::ser::MaybeReadable for $st {
601                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Option<Self>, $crate::ln::msgs::DecodeError> {
602                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
603                                 match id {
604                                         $($variant_id => {
605                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
606                                                 // in the same function body. Instead, we define a closure and call it.
607                                                 let f = || {
608                                                         $(
609                                                                 init_tlv_field_var!($field, $fieldty);
610                                                         )*
611                                                         read_tlv_fields!(reader, {
612                                                                 $(($type, $field, $fieldty)),*
613                                                         });
614                                                         Ok(Some($st::$variant_name {
615                                                                 $(
616                                                                         $field: init_tlv_based_struct_field!($field, $fieldty)
617                                                                 ),*
618                                                         }))
619                                                 };
620                                                 f()
621                                         }),*
622                                         $($($tuple_variant_id => {
623                                                 Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
624                                         }),*)*
625                                         _ if id % 2 == 1 => Ok(None),
626                                         _ => Err(DecodeError::UnknownRequiredFeature),
627                                 }
628                         }
629                 }
630
631         }
632 }
633
634 /// Implement Readable and Writeable for an enum, with struct variants stored as TLVs and tuple
635 /// variants stored directly.
636 /// The format is, for example
637 /// impl_writeable_tlv_based_enum!(EnumName,
638 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
639 ///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, vec_type)};
640 ///   (2, TupleVariantA), (3, TupleVariantB),
641 /// );
642 /// The type is written as a single byte, followed by any variant data.
643 /// Attempts to read an unknown type byte result in DecodeError::UnknownRequiredFeature.
644 macro_rules! impl_writeable_tlv_based_enum {
645         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
646                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
647         ),* $(,)*;
648         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
649                 _impl_writeable_tlv_based_enum_common!($st,
650                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
651                         $(($tuple_variant_id, $tuple_variant_name)),*);
652
653                 impl $crate::util::ser::Readable for $st {
654                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
655                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
656                                 match id {
657                                         $($variant_id => {
658                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
659                                                 // in the same function body. Instead, we define a closure and call it.
660                                                 let f = || {
661                                                         $(
662                                                                 init_tlv_field_var!($field, $fieldty);
663                                                         )*
664                                                         read_tlv_fields!(reader, {
665                                                                 $(($type, $field, $fieldty)),*
666                                                         });
667                                                         Ok($st::$variant_name {
668                                                                 $(
669                                                                         $field: init_tlv_based_struct_field!($field, $fieldty)
670                                                                 ),*
671                                                         })
672                                                 };
673                                                 f()
674                                         }),*
675                                         $($tuple_variant_id => {
676                                                 Ok($st::$tuple_variant_name(Readable::read(reader)?))
677                                         }),*
678                                         _ => {
679                                                 Err(DecodeError::UnknownRequiredFeature)
680                                         },
681                                 }
682                         }
683                 }
684         }
685 }
686
687 #[cfg(test)]
688 mod tests {
689         use crate::io::{self, Cursor};
690         use crate::prelude::*;
691         use crate::ln::msgs::DecodeError;
692         use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
693         use bitcoin::secp256k1::PublicKey;
694
695         // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
696         // the encoding layer in the BOLTs has no such concept, though it makes our macros easier to
697         // work with so they're baked into the decoder. Thus, we have a few additional tests below
698         fn tlv_reader(s: &[u8]) -> Result<(u64, u32, Option<u32>), DecodeError> {
699                 let mut s = Cursor::new(s);
700                 let mut a: u64 = 0;
701                 let mut b: u32 = 0;
702                 let mut c: Option<u32> = None;
703                 decode_tlv_stream!(&mut s, {(2, a, required), (3, b, required), (4, c, option)});
704                 Ok((a, b, c))
705         }
706
707         #[test]
708         fn tlv_v_short_read() {
709                 // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
710                 if let Err(DecodeError::ShortRead) = tlv_reader(&::hex::decode(
711                                 concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
712                                 ).unwrap()[..]) {
713                 } else { panic!(); }
714         }
715
716         #[test]
717         fn tlv_types_out_of_order() {
718                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
719                                 concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
720                                 ).unwrap()[..]) {
721                 } else { panic!(); }
722                 // ...even if its some field we don't understand
723                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
724                                 concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
725                                 ).unwrap()[..]) {
726                 } else { panic!(); }
727         }
728
729         #[test]
730         fn tlv_req_type_missing_or_extra() {
731                 // It's also bad if they included even fields we don't understand
732                 if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&::hex::decode(
733                                 concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
734                                 ).unwrap()[..]) {
735                 } else { panic!(); }
736                 // ... or if they're missing fields we need
737                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
738                                 concat!("0100", "0208deadbeef1badbeef")
739                                 ).unwrap()[..]) {
740                 } else { panic!(); }
741                 // ... even if that field is even
742                 if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
743                                 concat!("0304deadbeef", "0500")
744                                 ).unwrap()[..]) {
745                 } else { panic!(); }
746         }
747
748         #[test]
749         fn tlv_simple_good_cases() {
750                 assert_eq!(tlv_reader(&::hex::decode(
751                                 concat!("0208deadbeef1badbeef", "03041bad1dea")
752                                 ).unwrap()[..]).unwrap(),
753                         (0xdeadbeef1badbeef, 0x1bad1dea, None));
754                 assert_eq!(tlv_reader(&::hex::decode(
755                                 concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
756                                 ).unwrap()[..]).unwrap(),
757                         (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
758         }
759
760         // BOLT TLV test cases
761         fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
762                 let mut s = Cursor::new(s);
763                 let mut tlv1: Option<HighZeroBytesDroppedBigSize<u64>> = None;
764                 let mut tlv2: Option<u64> = None;
765                 let mut tlv3: Option<(PublicKey, u64, u64)> = None;
766                 let mut tlv4: Option<u16> = None;
767                 decode_tlv_stream!(&mut s, {(1, tlv1, option), (2, tlv2, option), (3, tlv3, option), (254, tlv4, option)});
768                 Ok((tlv1, tlv2, tlv3, tlv4))
769         }
770
771         #[test]
772         fn bolt_tlv_bogus_stream() {
773                 macro_rules! do_test {
774                         ($stream: expr, $reason: ident) => {
775                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
776                                 } else { panic!(); }
777                         }
778                 }
779
780                 // TLVs from the BOLT test cases which should not decode as either n1 or n2
781                 do_test!(concat!("fd01"), ShortRead);
782                 do_test!(concat!("fd0001", "00"), InvalidValue);
783                 do_test!(concat!("fd0101"), ShortRead);
784                 do_test!(concat!("0f", "fd"), ShortRead);
785                 do_test!(concat!("0f", "fd26"), ShortRead);
786                 do_test!(concat!("0f", "fd2602"), ShortRead);
787                 do_test!(concat!("0f", "fd0001", "00"), InvalidValue);
788                 do_test!(concat!("0f", "fd0201", "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"), ShortRead);
789
790                 do_test!(concat!("12", "00"), UnknownRequiredFeature);
791                 do_test!(concat!("fd0102", "00"), UnknownRequiredFeature);
792                 do_test!(concat!("fe01000002", "00"), UnknownRequiredFeature);
793                 do_test!(concat!("ff0100000000000002", "00"), UnknownRequiredFeature);
794         }
795
796         #[test]
797         fn bolt_tlv_bogus_n1_stream() {
798                 macro_rules! do_test {
799                         ($stream: expr, $reason: ident) => {
800                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
801                                 } else { panic!(); }
802                         }
803                 }
804
805                 // TLVs from the BOLT test cases which should not decode as n1
806                 do_test!(concat!("01", "09", "ffffffffffffffffff"), InvalidValue);
807                 do_test!(concat!("01", "01", "00"), InvalidValue);
808                 do_test!(concat!("01", "02", "0001"), InvalidValue);
809                 do_test!(concat!("01", "03", "000100"), InvalidValue);
810                 do_test!(concat!("01", "04", "00010000"), InvalidValue);
811                 do_test!(concat!("01", "05", "0001000000"), InvalidValue);
812                 do_test!(concat!("01", "06", "000100000000"), InvalidValue);
813                 do_test!(concat!("01", "07", "00010000000000"), InvalidValue);
814                 do_test!(concat!("01", "08", "0001000000000000"), InvalidValue);
815                 do_test!(concat!("02", "07", "01010101010101"), ShortRead);
816                 do_test!(concat!("02", "09", "010101010101010101"), InvalidValue);
817                 do_test!(concat!("03", "21", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb"), ShortRead);
818                 do_test!(concat!("03", "29", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001"), ShortRead);
819                 do_test!(concat!("03", "30", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb000000000000000100000000000001"), ShortRead);
820                 do_test!(concat!("03", "31", "043da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"), InvalidValue);
821                 do_test!(concat!("03", "32", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001000000000000000001"), InvalidValue);
822                 do_test!(concat!("fd00fe", "00"), ShortRead);
823                 do_test!(concat!("fd00fe", "01", "01"), ShortRead);
824                 do_test!(concat!("fd00fe", "03", "010101"), InvalidValue);
825                 do_test!(concat!("00", "00"), UnknownRequiredFeature);
826
827                 do_test!(concat!("02", "08", "0000000000000226", "01", "01", "2a"), InvalidValue);
828                 do_test!(concat!("02", "08", "0000000000000231", "02", "08", "0000000000000451"), InvalidValue);
829                 do_test!(concat!("1f", "00", "0f", "01", "2a"), InvalidValue);
830                 do_test!(concat!("1f", "00", "1f", "01", "2a"), InvalidValue);
831
832                 // The last BOLT test modified to not require creating a new decoder for one trivial test.
833                 do_test!(concat!("ffffffffffffffffff", "00", "01", "00"), InvalidValue);
834         }
835
836         #[test]
837         fn bolt_tlv_valid_n1_stream() {
838                 macro_rules! do_test {
839                         ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
840                                 if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
841                                         assert_eq!(tlv1.map(|v| v.0), $tlv1);
842                                         assert_eq!(tlv2, $tlv2);
843                                         assert_eq!(tlv3, $tlv3);
844                                         assert_eq!(tlv4, $tlv4);
845                                 } else { panic!(); }
846                         }
847                 }
848
849                 do_test!(concat!(""), None, None, None, None);
850                 do_test!(concat!("21", "00"), None, None, None, None);
851                 do_test!(concat!("fd0201", "00"), None, None, None, None);
852                 do_test!(concat!("fd00fd", "00"), None, None, None, None);
853                 do_test!(concat!("fd00ff", "00"), None, None, None, None);
854                 do_test!(concat!("fe02000001", "00"), None, None, None, None);
855                 do_test!(concat!("ff0200000000000001", "00"), None, None, None, None);
856
857                 do_test!(concat!("01", "00"), Some(0), None, None, None);
858                 do_test!(concat!("01", "01", "01"), Some(1), None, None, None);
859                 do_test!(concat!("01", "02", "0100"), Some(256), None, None, None);
860                 do_test!(concat!("01", "03", "010000"), Some(65536), None, None, None);
861                 do_test!(concat!("01", "04", "01000000"), Some(16777216), None, None, None);
862                 do_test!(concat!("01", "05", "0100000000"), Some(4294967296), None, None, None);
863                 do_test!(concat!("01", "06", "010000000000"), Some(1099511627776), None, None, None);
864                 do_test!(concat!("01", "07", "01000000000000"), Some(281474976710656), None, None, None);
865                 do_test!(concat!("01", "08", "0100000000000000"), Some(72057594037927936), None, None, None);
866                 do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
867                 do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
868                         None, None, Some((
869                                 PublicKey::from_slice(&::hex::decode("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
870                         None);
871                 do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
872         }
873
874         fn do_simple_test_tlv_write() -> Result<(), io::Error> {
875                 let mut stream = VecWriter(Vec::new());
876
877                 stream.0.clear();
878                 encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
879                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
880
881                 stream.0.clear();
882                 encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
883                 assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
884
885                 stream.0.clear();
886                 encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
887                 assert_eq!(stream.0, ::hex::decode("040402abcd").unwrap());
888
889                 stream.0.clear();
890                 encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
891                 assert_eq!(stream.0, ::hex::decode("06fd00ff02abcd").unwrap());
892
893                 stream.0.clear();
894                 encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
895                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
896
897                 stream.0.clear();
898                 encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
899                 assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
900
901                 Ok(())
902         }
903
904         #[test]
905         fn simple_test_tlv_write() {
906                 do_simple_test_tlv_write().unwrap();
907         }
908 }