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[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 //! Some macros that implement [`Readable`]/[`Writeable`] traits for lightning messages.
11 //! They also handle serialization and deserialization of TLVs.
12 //!
13 //! [`Readable`]: crate::util::ser::Readable
14 //! [`Writeable`]: crate::util::ser::Writeable
15
16 // There are quite a few TLV serialization "types" which behave differently. We currently only
17 // publicly document the `optional` and `required` types, not supporting anything else publicly and
18 // changing them at will.
19 //
20 // Some of the other types include:
21 //  * (default_value, $default) - reads optionally, reading $default if no TLV is present
22 //  * (static_value, $value) - ignores any TLVs, always using $value
23 //  * required_vec - reads into a Vec without a length prefix, failing if no TLV is present.
24 //  * optional_vec - reads into an Option<Vec> without a length prefix, continuing if no TLV is
25 //                   present. Writes from a Vec directly, only if any elements are present. Note
26 //                   that the struct deserialization macros return a Vec, not an Option.
27 //  * upgradable_option - reads via MaybeReadable.
28 //  * upgradable_required - reads via MaybeReadable, requiring a TLV be present but may return None
29 //                          if MaybeReadable::read() returns None.
30
31 /// Implements serialization for a single TLV record.
32 /// This is exported for use by other exported macros, do not use directly.
33 #[doc(hidden)]
34 #[macro_export]
35 macro_rules! _encode_tlv {
36         ($stream: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
37                 $crate::_encode_tlv!($stream, $type, $field, required)
38         };
39         ($stream: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
40                 let _ = &$field; // Ensure we "use" the $field
41         };
42         ($stream: expr, $type: expr, $field: expr, required) => {
43                 BigSize($type).write($stream)?;
44                 BigSize($field.serialized_length() as u64).write($stream)?;
45                 $field.write($stream)?;
46         };
47         ($stream: expr, $type: expr, $field: expr, required_vec) => {
48                 $crate::_encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
49         };
50         ($stream: expr, $optional_type: expr, $optional_field: expr, option) => {
51                 if let Some(ref field) = $optional_field {
52                         BigSize($optional_type).write($stream)?;
53                         BigSize(field.serialized_length() as u64).write($stream)?;
54                         field.write($stream)?;
55                 }
56         };
57         ($stream: expr, $type: expr, $field: expr, optional_vec) => {
58                 if !$field.is_empty() {
59                         $crate::_encode_tlv!($stream, $type, $field, required_vec);
60                 }
61         };
62         ($stream: expr, $type: expr, $field: expr, upgradable_required) => {
63                 $crate::_encode_tlv!($stream, $type, $field, required);
64         };
65         ($stream: expr, $type: expr, $field: expr, upgradable_option) => {
66                 $crate::_encode_tlv!($stream, $type, $field, option);
67         };
68         ($stream: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
69                 $crate::_encode_tlv!($stream, $type, $field.map(|f| $encoding(f)), option);
70         };
71         ($stream: expr, $type: expr, $field: expr, (option, encoding: $fieldty: ty)) => {
72                 $crate::_encode_tlv!($stream, $type, $field, option);
73         };
74         ($stream: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
75                 // Just a read-mapped type
76                 $crate::_encode_tlv!($stream, $type, $field, option);
77         };
78 }
79
80 /// Panics if the last seen TLV type is not numerically less than the TLV type currently being checked.
81 /// This is exported for use by other exported macros, do not use directly.
82 #[doc(hidden)]
83 #[macro_export]
84 macro_rules! _check_encoded_tlv_order {
85         ($last_type: expr, $type: expr, (static_value, $value: expr)) => { };
86         ($last_type: expr, $type: expr, $fieldty: tt) => {
87                 if let Some(t) = $last_type {
88                         #[allow(unused_comparisons)] // Note that $type may be 0 making the following comparison always false
89                         (debug_assert!(t < $type))
90                 }
91                 $last_type = Some($type);
92         };
93 }
94
95 /// Implements the TLVs serialization part in a [`Writeable`] implementation of a struct.
96 ///
97 /// This should be called inside a method which returns `Result<_, `[`io::Error`]`>`, such as
98 /// [`Writeable::write`]. It will only return an `Err` if the stream `Err`s or [`Writeable::write`]
99 /// on one of the fields `Err`s.
100 ///
101 /// `$stream` must be a `&mut `[`Writer`] which will receive the bytes for each TLV in the stream.
102 ///
103 /// Fields MUST be sorted in `$type`-order.
104 ///
105 /// Note that the lightning TLV requirements require that a single type not appear more than once,
106 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
107 /// decoder.
108 ///
109 /// Any `option` fields which have a value of `None` will not be serialized at all.
110 ///
111 /// For example,
112 /// ```
113 /// # use lightning::encode_tlv_stream;
114 /// # fn write<W: lightning::util::ser::Writer> (stream: &mut W) -> Result<(), lightning::io::Error> {
115 /// let mut required_value = 0u64;
116 /// let mut optional_value: Option<u64> = None;
117 /// encode_tlv_stream!(stream, {
118 ///     (0, required_value, required),
119 ///     (1, Some(42u64), option),
120 ///     (2, optional_value, option),
121 /// });
122 /// // At this point `required_value` has been written as a TLV of type 0, `42u64` has been written
123 /// // as a TLV of type 1 (indicating the reader may ignore it if it is not understood), and *no*
124 /// // TLV is written with type 2.
125 /// # Ok(())
126 /// # }
127 /// ```
128 ///
129 /// [`Writeable`]: crate::util::ser::Writeable
130 /// [`io::Error`]: crate::io::Error
131 /// [`Writeable::write`]: crate::util::ser::Writeable::write
132 /// [`Writer`]: crate::util::ser::Writer
133 #[macro_export]
134 macro_rules! encode_tlv_stream {
135         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
136                 $crate::_encode_tlv_stream!($stream, {$(($type, $field, $fieldty)),*})
137         }
138 }
139
140 /// Implementation of [`encode_tlv_stream`].
141 /// This is exported for use by other exported macros, do not use directly.
142 #[doc(hidden)]
143 #[macro_export]
144 macro_rules! _encode_tlv_stream {
145         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => { {
146                 $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, &[])
147         } };
148         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}, $extra_tlvs: expr) => { {
149                 #[allow(unused_imports)]
150                 use $crate::{
151                         ln::msgs::DecodeError,
152                         util::ser,
153                         util::ser::BigSize,
154                         util::ser::Writeable,
155                 };
156
157                 $(
158                         $crate::_encode_tlv!($stream, $type, $field, $fieldty);
159                 )*
160                 for tlv in $extra_tlvs {
161                         let (typ, value): &(u64, Vec<u8>) = tlv;
162                         $crate::_encode_tlv!($stream, *typ, *value, required_vec);
163                 }
164
165                 #[allow(unused_mut, unused_variables, unused_assignments)]
166                 #[cfg(debug_assertions)]
167                 {
168                         let mut last_seen: Option<u64> = None;
169                         $(
170                                 $crate::_check_encoded_tlv_order!(last_seen, $type, $fieldty);
171                         )*
172                         for tlv in $extra_tlvs {
173                                 let (typ, _): &(u64, Vec<u8>) = tlv;
174                                 $crate::_check_encoded_tlv_order!(last_seen, *typ, required_vec);
175                         }
176                 }
177         } };
178 }
179
180 /// Adds the length of the serialized field to a [`LengthCalculatingWriter`].
181 /// This is exported for use by other exported macros, do not use directly.
182 ///
183 /// [`LengthCalculatingWriter`]: crate::util::ser::LengthCalculatingWriter
184 #[doc(hidden)]
185 #[macro_export]
186 macro_rules! _get_varint_length_prefixed_tlv_length {
187         ($len: expr, $type: expr, $field: expr, (default_value, $default: expr)) => {
188                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required)
189         };
190         ($len: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
191         };
192         ($len: expr, $type: expr, $field: expr, required) => {
193                 BigSize($type).write(&mut $len).expect("No in-memory data may fail to serialize");
194                 let field_len = $field.serialized_length();
195                 BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
196                 $len.0 += field_len;
197         };
198         ($len: expr, $type: expr, $field: expr, required_vec) => {
199                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
200         };
201         ($len: expr, $optional_type: expr, $optional_field: expr, option) => {
202                 if let Some(ref field) = $optional_field {
203                         BigSize($optional_type).write(&mut $len).expect("No in-memory data may fail to serialize");
204                         let field_len = field.serialized_length();
205                         BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
206                         $len.0 += field_len;
207                 }
208         };
209         ($len: expr, $type: expr, $field: expr, optional_vec) => {
210                 if !$field.is_empty() {
211                         $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required_vec);
212                 }
213         };
214         ($len: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
215                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
216         };
217         ($len: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
218                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field.map(|f| $encoding(f)), option);
219         };
220         ($len: expr, $type: expr, $field: expr, upgradable_required) => {
221                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required);
222         };
223         ($len: expr, $type: expr, $field: expr, upgradable_option) => {
224                 $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
225         };
226 }
227
228 /// See the documentation of [`write_tlv_fields`].
229 /// This is exported for use by other exported macros, do not use directly.
230 #[doc(hidden)]
231 #[macro_export]
232 macro_rules! _encode_varint_length_prefixed_tlv {
233         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}) => { {
234                 $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*}, &[])
235         } };
236         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}, $extra_tlvs: expr) => { {
237                 extern crate alloc;
238                 use $crate::util::ser::BigSize;
239                 use alloc::vec::Vec;
240                 let len = {
241                         #[allow(unused_mut)]
242                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
243                         $(
244                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, $field, $fieldty);
245                         )*
246                         for tlv in $extra_tlvs {
247                                 let (typ, value): &(u64, Vec<u8>) = tlv;
248                                 $crate::_get_varint_length_prefixed_tlv_length!(len, *typ, *value, required_vec);
249                         }
250                         len.0
251                 };
252                 BigSize(len as u64).write($stream)?;
253                 $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, $extra_tlvs);
254         } };
255 }
256
257 /// Errors if there are missing required TLV types between the last seen type and the type currently being processed.
258 /// This is exported for use by other exported macros, do not use directly.
259 #[doc(hidden)]
260 #[macro_export]
261 macro_rules! _check_decoded_tlv_order {
262         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
263                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
264                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
265                 if invalid_order {
266                         $field = $default.into();
267                 }
268         }};
269         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (static_value, $value: expr)) => {
270         };
271         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required) => {{
272                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
273                 let invalid_order = ($last_seen_type.is_none() || $last_seen_type.unwrap() < $type) && $typ.0 > $type;
274                 if invalid_order {
275                         return Err(DecodeError::InvalidValue);
276                 }
277         }};
278         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
279                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
280         }};
281         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
282                 // no-op
283         }};
284         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required_vec) => {{
285                 $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
286         }};
287         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, optional_vec) => {{
288                 // no-op
289         }};
290         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_required) => {{
291                 _check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required)
292         }};
293         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_option) => {{
294                 // no-op
295         }};
296         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
297                 // no-op
298         }};
299         ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
300                 // no-op
301         }};
302 }
303
304 /// Errors if there are missing required TLV types after the last seen type.
305 /// This is exported for use by other exported macros, do not use directly.
306 #[doc(hidden)]
307 #[macro_export]
308 macro_rules! _check_missing_tlv {
309         ($last_seen_type: expr, $type: expr, $field: ident, (default_value, $default: expr)) => {{
310                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
311                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
312                 if missing_req_type {
313                         $field = $default.into();
314                 }
315         }};
316         ($last_seen_type: expr, $type: expr, $field: expr, (static_value, $value: expr)) => {
317                 $field = $value;
318         };
319         ($last_seen_type: expr, $type: expr, $field: ident, required) => {{
320                 #[allow(unused_comparisons)] // Note that $type may be 0 making the second comparison always false
321                 let missing_req_type = $last_seen_type.is_none() || $last_seen_type.unwrap() < $type;
322                 if missing_req_type {
323                         return Err(DecodeError::InvalidValue);
324                 }
325         }};
326         ($last_seen_type: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
327                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
328         }};
329         ($last_seen_type: expr, $type: expr, $field: ident, required_vec) => {{
330                 $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
331         }};
332         ($last_seen_type: expr, $type: expr, $field: ident, option) => {{
333                 // no-op
334         }};
335         ($last_seen_type: expr, $type: expr, $field: ident, optional_vec) => {{
336                 // no-op
337         }};
338         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_required) => {{
339                 _check_missing_tlv!($last_seen_type, $type, $field, required)
340         }};
341         ($last_seen_type: expr, $type: expr, $field: ident, upgradable_option) => {{
342                 // no-op
343         }};
344         ($last_seen_type: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
345                 // no-op
346         }};
347         ($last_seen_type: expr, $type: expr, $field: ident, (option, encoding: $encoding: tt)) => {{
348                 // no-op
349         }};
350 }
351
352 /// Implements deserialization for a single TLV record.
353 /// This is exported for use by other exported macros, do not use directly.
354 #[doc(hidden)]
355 #[macro_export]
356 macro_rules! _decode_tlv {
357         ($reader: expr, $field: ident, (default_value, $default: expr)) => {{
358                 $crate::_decode_tlv!($reader, $field, required)
359         }};
360         ($reader: expr, $field: ident, (static_value, $value: expr)) => {{
361         }};
362         ($reader: expr, $field: ident, required) => {{
363                 $field = $crate::util::ser::Readable::read(&mut $reader)?;
364         }};
365         ($reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
366                 $field = $trait::read(&mut $reader $(, $read_arg)*)?;
367         }};
368         ($reader: expr, $field: ident, required_vec) => {{
369                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
370                 $field = f.0;
371         }};
372         ($reader: expr, $field: ident, option) => {{
373                 $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
374         }};
375         ($reader: expr, $field: ident, optional_vec) => {{
376                 let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
377                 $field = Some(f.0);
378         }};
379         // `upgradable_required` indicates we're reading a required TLV that may have been upgraded
380         // without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
381         // field is present but we can no longer understand it.
382         // Note that this variant can only be used within a `MaybeReadable` read.
383         ($reader: expr, $field: ident, upgradable_required) => {{
384                 $field = match $crate::util::ser::MaybeReadable::read(&mut $reader)? {
385                         Some(res) => res,
386                         _ => return Ok(None)
387                 };
388         }};
389         // `upgradable_option` indicates we're reading an Option-al TLV that may have been upgraded
390         // without backwards compat. $field will be None if the TLV is missing or if the field is present
391         // but we can no longer understand it.
392         ($reader: expr, $field: ident, upgradable_option) => {{
393                 $field = $crate::util::ser::MaybeReadable::read(&mut $reader)?;
394         }};
395         ($reader: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
396                 $field = Some($trait::read(&mut $reader $(, $read_arg)*)?);
397         }};
398         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident, $encoder:ty))) => {{
399                 $crate::_decode_tlv!($reader, $field, (option, encoding: ($fieldty, $encoding)));
400         }};
401         ($reader: expr, $field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {{
402                 $field = {
403                         let field: $encoding<$fieldty> = ser::Readable::read(&mut $reader)?;
404                         Some(field.0)
405                 };
406         }};
407         ($reader: expr, $field: ident, (option, encoding: $fieldty: ty)) => {{
408                 $crate::_decode_tlv!($reader, $field, option);
409         }};
410 }
411
412 /// Checks if `$val` matches `$type`.
413 /// This is exported for use by other exported macros, do not use directly.
414 #[doc(hidden)]
415 #[macro_export]
416 macro_rules! _decode_tlv_stream_match_check {
417         ($val: ident, $type: expr, (static_value, $value: expr)) => { false };
418         ($val: ident, $type: expr, $fieldty: tt) => { $val == $type }
419 }
420
421 /// Implements the TLVs deserialization part in a [`Readable`] implementation of a struct.
422 ///
423 /// This should be called inside a method which returns `Result<_, `[`DecodeError`]`>`, such as
424 /// [`Readable::read`]. It will either return an `Err` or ensure all `required` fields have been
425 /// read and optionally read `optional` fields.
426 ///
427 /// `$stream` must be a [`Read`] and will be fully consumed, reading until no more bytes remain
428 /// (i.e. it returns [`DecodeError::ShortRead`]).
429 ///
430 /// Fields MUST be sorted in `$type`-order.
431 ///
432 /// Note that the lightning TLV requirements require that a single type not appear more than once,
433 /// that TLVs are sorted in type-ascending order, and that any even types be understood by the
434 /// decoder.
435 ///
436 /// For example,
437 /// ```
438 /// # use lightning::decode_tlv_stream;
439 /// # fn read<R: lightning::io::Read> (stream: R) -> Result<(), lightning::ln::msgs::DecodeError> {
440 /// let mut required_value = 0u64;
441 /// let mut optional_value: Option<u64> = None;
442 /// decode_tlv_stream!(stream, {
443 ///     (0, required_value, required),
444 ///     (2, optional_value, option),
445 /// });
446 /// // At this point, `required_value` has been overwritten with the TLV with type 0.
447 /// // `optional_value` may have been overwritten, setting it to `Some` if a TLV with type 2 was
448 /// // present.
449 /// # Ok(())
450 /// # }
451 /// ```
452 ///
453 /// [`Readable`]: crate::util::ser::Readable
454 /// [`DecodeError`]: crate::ln::msgs::DecodeError
455 /// [`Readable::read`]: crate::util::ser::Readable::read
456 /// [`Read`]: crate::io::Read
457 /// [`DecodeError::ShortRead`]: crate::ln::msgs::DecodeError::ShortRead
458 #[macro_export]
459 macro_rules! decode_tlv_stream {
460         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
461                 let rewind = |_, _| { unreachable!() };
462                 $crate::_decode_tlv_stream_range!($stream, .., rewind, {$(($type, $field, $fieldty)),*});
463         }
464 }
465
466 /// Similar to [`decode_tlv_stream`] with a custom TLV decoding capabilities.
467 ///
468 /// `$decode_custom_tlv` is a closure that may be optionally provided to handle custom message types.
469 /// If it is provided, it will be called with the custom type and the [`FixedLengthReader`] containing
470 /// the message contents. It should return `Ok(true)` if the custom message is successfully parsed,
471 /// `Ok(false)` if the message type is unknown, and `Err(`[`DecodeError`]`)` if parsing fails.
472 ///
473 /// [`FixedLengthReader`]: crate::util::ser::FixedLengthReader
474 /// [`DecodeError`]: crate::ln::msgs::DecodeError
475 macro_rules! decode_tlv_stream_with_custom_tlv_decode {
476         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
477          $(, $decode_custom_tlv: expr)?) => { {
478                 let rewind = |_, _| { unreachable!() };
479                 _decode_tlv_stream_range!(
480                         $stream, .., rewind, {$(($type, $field, $fieldty)),*} $(, $decode_custom_tlv)?
481                 );
482         } }
483 }
484
485 #[doc(hidden)]
486 #[macro_export]
487 macro_rules! _decode_tlv_stream_range {
488         ($stream: expr, $range: expr, $rewind: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
489          $(, $decode_custom_tlv: expr)?) => { {
490                 use $crate::ln::msgs::DecodeError;
491                 let mut last_seen_type: Option<u64> = None;
492                 let mut stream_ref = $stream;
493                 'tlv_read: loop {
494                         use $crate::util::ser;
495
496                         // First decode the type of this TLV:
497                         let typ: ser::BigSize = {
498                                 // We track whether any bytes were read during the consensus_decode call to
499                                 // determine whether we should break or return ShortRead if we get an
500                                 // UnexpectedEof. This should in every case be largely cosmetic, but its nice to
501                                 // pass the TLV test vectors exactly, which require this distinction.
502                                 let mut tracking_reader = ser::ReadTrackingReader::new(&mut stream_ref);
503                                 match <$crate::util::ser::BigSize as $crate::util::ser::Readable>::read(&mut tracking_reader) {
504                                         Err(DecodeError::ShortRead) => {
505                                                 if !tracking_reader.have_read {
506                                                         break 'tlv_read;
507                                                 } else {
508                                                         return Err(DecodeError::ShortRead);
509                                                 }
510                                         },
511                                         Err(e) => return Err(e),
512                                         Ok(t) => if core::ops::RangeBounds::contains(&$range, &t.0) { t } else {
513                                                 drop(tracking_reader);
514
515                                                 // Assumes the type id is minimally encoded, which is enforced on read.
516                                                 use $crate::util::ser::Writeable;
517                                                 let bytes_read = t.serialized_length();
518                                                 $rewind(stream_ref, bytes_read);
519                                                 break 'tlv_read;
520                                         },
521                                 }
522                         };
523
524                         // Types must be unique and monotonically increasing:
525                         match last_seen_type {
526                                 Some(t) if typ.0 <= t => {
527                                         return Err(DecodeError::InvalidValue);
528                                 },
529                                 _ => {},
530                         }
531                         // As we read types, make sure we hit every required type between `last_seen_type` and `typ`:
532                         $({
533                                 $crate::_check_decoded_tlv_order!(last_seen_type, typ, $type, $field, $fieldty);
534                         })*
535                         last_seen_type = Some(typ.0);
536
537                         // Finally, read the length and value itself:
538                         let length: ser::BigSize = $crate::util::ser::Readable::read(&mut stream_ref)?;
539                         let mut s = ser::FixedLengthReader::new(&mut stream_ref, length.0);
540                         match typ.0 {
541                                 $(_t if $crate::_decode_tlv_stream_match_check!(_t, $type, $fieldty) => {
542                                         $crate::_decode_tlv!(s, $field, $fieldty);
543                                         if s.bytes_remain() {
544                                                 s.eat_remaining()?; // Return ShortRead if there's actually not enough bytes
545                                                 return Err(DecodeError::InvalidValue);
546                                         }
547                                 },)*
548                                 t => {
549                                         $(
550                                                 if $decode_custom_tlv(t, &mut s)? {
551                                                         // If a custom TLV was successfully read (i.e. decode_custom_tlv returns true),
552                                                         // continue to the next TLV read.
553                                                         s.eat_remaining()?;
554                                                         continue 'tlv_read;
555                                                 }
556                                         )?
557                                         if t % 2 == 0 {
558                                                 return Err(DecodeError::UnknownRequiredFeature);
559                                         }
560                                 }
561                         }
562                         s.eat_remaining()?;
563                 }
564                 // Make sure we got to each required type after we've read every TLV:
565                 $({
566                         $crate::_check_missing_tlv!(last_seen_type, $type, $field, $fieldty);
567                 })*
568         } }
569 }
570
571 /// Implements [`Readable`]/[`Writeable`] for a message struct that may include non-TLV and
572 /// TLV-encoded parts.
573 ///
574 /// This is useful to implement a [`CustomMessageReader`].
575 ///
576 /// Currently `$fieldty` may only be `option`, i.e., `$tlvfield` is optional field.
577 ///
578 /// For example,
579 /// ```
580 /// # use lightning::impl_writeable_msg;
581 /// struct MyCustomMessage {
582 ///     pub field_1: u32,
583 ///     pub field_2: bool,
584 ///     pub field_3: String,
585 ///     pub tlv_optional_integer: Option<u32>,
586 /// }
587 ///
588 /// impl_writeable_msg!(MyCustomMessage, {
589 ///     field_1,
590 ///     field_2,
591 ///     field_3
592 /// }, {
593 ///     (1, tlv_optional_integer, option),
594 /// });
595 /// ```
596 ///
597 /// [`Readable`]: crate::util::ser::Readable
598 /// [`Writeable`]: crate::util::ser::Writeable
599 /// [`CustomMessageReader`]: crate::ln::wire::CustomMessageReader
600 #[macro_export]
601 macro_rules! impl_writeable_msg {
602         ($st:ident, {$($field:ident),* $(,)*}, {$(($type: expr, $tlvfield: ident, $fieldty: tt)),* $(,)*}) => {
603                 impl $crate::util::ser::Writeable for $st {
604                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
605                                 $( self.$field.write(w)?; )*
606                                 $crate::encode_tlv_stream!(w, {$(($type, self.$tlvfield.as_ref(), $fieldty)),*});
607                                 Ok(())
608                         }
609                 }
610                 impl $crate::util::ser::Readable for $st {
611                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
612                                 $(let $field = $crate::util::ser::Readable::read(r)?;)*
613                                 $($crate::_init_tlv_field_var!($tlvfield, $fieldty);)*
614                                 $crate::decode_tlv_stream!(r, {$(($type, $tlvfield, $fieldty)),*});
615                                 Ok(Self {
616                                         $($field),*,
617                                         $($tlvfield),*
618                                 })
619                         }
620                 }
621         }
622 }
623
624 macro_rules! impl_writeable {
625         ($st:ident, {$($field:ident),*}) => {
626                 impl $crate::util::ser::Writeable for $st {
627                         fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
628                                 $( self.$field.write(w)?; )*
629                                 Ok(())
630                         }
631
632                         #[inline]
633                         fn serialized_length(&self) -> usize {
634                                 let mut len_calc = 0;
635                                 $( len_calc += self.$field.serialized_length(); )*
636                                 return len_calc;
637                         }
638                 }
639
640                 impl $crate::util::ser::Readable for $st {
641                         fn read<R: $crate::io::Read>(r: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
642                                 Ok(Self {
643                                         $($field: $crate::util::ser::Readable::read(r)?),*
644                                 })
645                         }
646                 }
647         }
648 }
649
650 /// Write out two bytes to indicate the version of an object.
651 ///
652 /// $this_version represents a unique version of a type. Incremented whenever the type's
653 /// serialization format has changed or has a new interpretation. Used by a type's reader to
654 /// determine how to interpret fields or if it can understand a serialized object.
655 ///
656 /// $min_version_that_can_read_this is the minimum reader version which can understand this
657 /// serialized object. Previous versions will simply err with a [`DecodeError::UnknownVersion`].
658 ///
659 /// Updates to either `$this_version` or `$min_version_that_can_read_this` should be included in
660 /// release notes.
661 ///
662 /// Both version fields can be specific to this type of object.
663 ///
664 /// [`DecodeError::UnknownVersion`]: crate::ln::msgs::DecodeError::UnknownVersion
665 macro_rules! write_ver_prefix {
666         ($stream: expr, $this_version: expr, $min_version_that_can_read_this: expr) => {
667                 $stream.write_all(&[$this_version; 1])?;
668                 $stream.write_all(&[$min_version_that_can_read_this; 1])?;
669         }
670 }
671
672 /// Writes out a suffix to an object as a length-prefixed TLV stream which contains potentially
673 /// backwards-compatible, optional fields which old nodes can happily ignore.
674 ///
675 /// It is written out in TLV format and, as with all TLV fields, unknown even fields cause a
676 /// [`DecodeError::UnknownRequiredFeature`] error, with unknown odd fields ignored.
677 ///
678 /// This is the preferred method of adding new fields that old nodes can ignore and still function
679 /// correctly.
680 ///
681 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
682 #[macro_export]
683 macro_rules! write_tlv_fields {
684         ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
685                 $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*})
686         }
687 }
688
689 /// Reads a prefix added by [`write_ver_prefix`], above. Takes the current version of the
690 /// serialization logic for this object. This is compared against the
691 /// `$min_version_that_can_read_this` added by [`write_ver_prefix`].
692 macro_rules! read_ver_prefix {
693         ($stream: expr, $this_version: expr) => { {
694                 let ver: u8 = Readable::read($stream)?;
695                 let min_ver: u8 = Readable::read($stream)?;
696                 if min_ver > $this_version {
697                         return Err(DecodeError::UnknownVersion);
698                 }
699                 ver
700         } }
701 }
702
703 /// Reads a suffix added by [`write_tlv_fields`].
704 ///
705 /// [`write_tlv_fields`]: crate::write_tlv_fields
706 #[macro_export]
707 macro_rules! read_tlv_fields {
708         ($stream: expr, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => { {
709                 let tlv_len: $crate::util::ser::BigSize = $crate::util::ser::Readable::read($stream)?;
710                 let mut rd = $crate::util::ser::FixedLengthReader::new($stream, tlv_len.0);
711                 $crate::decode_tlv_stream!(&mut rd, {$(($type, $field, $fieldty)),*});
712                 rd.eat_remaining().map_err(|_| $crate::ln::msgs::DecodeError::ShortRead)?;
713         } }
714 }
715
716 /// Initializes the struct fields.
717 ///
718 /// This is exported for use by other exported macros, do not use directly.
719 #[doc(hidden)]
720 #[macro_export]
721 macro_rules! _init_tlv_based_struct_field {
722         ($field: ident, (default_value, $default: expr)) => {
723                 $field.0.unwrap()
724         };
725         ($field: ident, (static_value, $value: expr)) => {
726                 $field
727         };
728         ($field: ident, option) => {
729                 $field
730         };
731         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
732                 $crate::_init_tlv_based_struct_field!($field, option)
733         };
734         ($field: ident, upgradable_required) => {
735                 $field.0.unwrap()
736         };
737         ($field: ident, upgradable_option) => {
738                 $field
739         };
740         ($field: ident, required) => {
741                 $field.0.unwrap()
742         };
743         ($field: ident, required_vec) => {
744                 $field
745         };
746         ($field: ident, optional_vec) => {
747                 $field.unwrap()
748         };
749 }
750
751 /// Initializes the variable we are going to read the TLV into.
752 ///
753 /// This is exported for use by other exported macros, do not use directly.
754 #[doc(hidden)]
755 #[macro_export]
756 macro_rules! _init_tlv_field_var {
757         ($field: ident, (default_value, $default: expr)) => {
758                 let mut $field = $crate::util::ser::RequiredWrapper(None);
759         };
760         ($field: ident, (static_value, $value: expr)) => {
761                 let $field;
762         };
763         ($field: ident, required) => {
764                 let mut $field = $crate::util::ser::RequiredWrapper(None);
765         };
766         ($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
767                 $crate::_init_tlv_field_var!($field, required);
768         };
769         ($field: ident, required_vec) => {
770                 let mut $field = Vec::new();
771         };
772         ($field: ident, option) => {
773                 let mut $field = None;
774         };
775         ($field: ident, optional_vec) => {
776                 let mut $field = Some(Vec::new());
777         };
778         ($field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
779                 $crate::_init_tlv_field_var!($field, option);
780         };
781         ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
782                 $crate::_init_tlv_field_var!($field, option);
783         };
784         ($field: ident, upgradable_required) => {
785                 let mut $field = $crate::util::ser::UpgradableRequired(None);
786         };
787         ($field: ident, upgradable_option) => {
788                 let mut $field = None;
789         };
790 }
791
792 /// Equivalent to running [`_init_tlv_field_var`] then [`read_tlv_fields`].
793 ///
794 /// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
795 /// `i64`.
796 ///
797 /// This is exported for use by other exported macros, do not use directly.
798 #[doc(hidden)]
799 #[macro_export]
800 macro_rules! _init_and_read_len_prefixed_tlv_fields {
801         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
802                 $(
803                         $crate::_init_tlv_field_var!($field, $fieldty);
804                 )*
805
806                 $crate::read_tlv_fields!($reader, {
807                         $(($type, $field, $fieldty)),*
808                 });
809         }
810 }
811
812 /// Equivalent to running [`_init_tlv_field_var`] then [`decode_tlv_stream`].
813 ///
814 /// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
815 /// `i64`.
816 macro_rules! _init_and_read_tlv_stream {
817         ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
818                 $(
819                         $crate::_init_tlv_field_var!($field, $fieldty);
820                 )*
821
822                 $crate::decode_tlv_stream!($reader, {
823                         $(($type, $field, $fieldty)),*
824                 });
825         }
826 }
827
828 /// Implements [`Readable`]/[`Writeable`] for a struct storing it as a set of TLVs
829 /// If `$fieldty` is `required`, then `$field` is a required field that is not an [`Option`] nor a [`Vec`].
830 /// If `$fieldty` is `(default_value, $default)`, then `$field` will be set to `$default` if not present.
831 /// If `$fieldty` is `option`, then `$field` is optional field.
832 /// If `$fieldty` is `optional_vec`, then `$field` is a [`Vec`], which needs to have its individual elements serialized.
833 ///    Note that for `optional_vec` no bytes are written if the vec is empty
834 ///
835 /// For example,
836 /// ```
837 /// # use lightning::impl_writeable_tlv_based;
838 /// struct LightningMessage {
839 ///     tlv_integer: u32,
840 ///     tlv_default_integer: u32,
841 ///     tlv_optional_integer: Option<u32>,
842 ///     tlv_vec_type_integer: Vec<u32>,
843 /// }
844 ///
845 /// impl_writeable_tlv_based!(LightningMessage, {
846 ///     (0, tlv_integer, required),
847 ///     (1, tlv_default_integer, (default_value, 7)),
848 ///     (2, tlv_optional_integer, option),
849 ///     (3, tlv_vec_type_integer, optional_vec),
850 /// });
851 /// ```
852 ///
853 /// [`Readable`]: crate::util::ser::Readable
854 /// [`Writeable`]: crate::util::ser::Writeable
855 #[macro_export]
856 macro_rules! impl_writeable_tlv_based {
857         ($st: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
858                 impl $crate::util::ser::Writeable for $st {
859                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
860                                 $crate::write_tlv_fields!(writer, {
861                                         $(($type, self.$field, $fieldty)),*
862                                 });
863                                 Ok(())
864                         }
865
866                         #[inline]
867                         fn serialized_length(&self) -> usize {
868                                 use $crate::util::ser::BigSize;
869                                 let len = {
870                                         #[allow(unused_mut)]
871                                         let mut len = $crate::util::ser::LengthCalculatingWriter(0);
872                                         $(
873                                                 $crate::_get_varint_length_prefixed_tlv_length!(len, $type, self.$field, $fieldty);
874                                         )*
875                                         len.0
876                                 };
877                                 let mut len_calc = $crate::util::ser::LengthCalculatingWriter(0);
878                                 BigSize(len as u64).write(&mut len_calc).expect("No in-memory data may fail to serialize");
879                                 len + len_calc.0
880                         }
881                 }
882
883                 impl $crate::util::ser::Readable for $st {
884                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
885                                 $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
886                                         $(($type, $field, $fieldty)),*
887                                 });
888                                 Ok(Self {
889                                         $(
890                                                 $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
891                                         ),*
892                                 })
893                         }
894                 }
895         }
896 }
897
898 /// Defines a struct for a TLV stream and a similar struct using references for non-primitive types,
899 /// implementing [`Readable`] for the former and [`Writeable`] for the latter. Useful as an
900 /// intermediary format when reading or writing a type encoded as a TLV stream. Note that each field
901 /// representing a TLV record has its type wrapped with an [`Option`]. A tuple consisting of a type
902 /// and a serialization wrapper may be given in place of a type when custom serialization is
903 /// required.
904 ///
905 /// [`Readable`]: crate::util::ser::Readable
906 /// [`Writeable`]: crate::util::ser::Writeable
907 macro_rules! tlv_stream {
908         ($name:ident, $nameref:ident, $range:expr, {
909                 $(($type:expr, $field:ident : $fieldty:tt)),* $(,)*
910         }) => {
911                 #[derive(Debug)]
912                 pub(super) struct $name {
913                         $(
914                                 pub(super) $field: Option<tlv_record_type!($fieldty)>,
915                         )*
916                 }
917
918                 #[cfg_attr(test, derive(PartialEq))]
919                 #[derive(Debug)]
920                 pub(crate) struct $nameref<'a> {
921                         $(
922                                 pub(super) $field: Option<tlv_record_ref_type!($fieldty)>,
923                         )*
924                 }
925
926                 impl<'a> $crate::util::ser::Writeable for $nameref<'a> {
927                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
928                                 encode_tlv_stream!(writer, {
929                                         $(($type, self.$field, (option, encoding: $fieldty))),*
930                                 });
931                                 Ok(())
932                         }
933                 }
934
935                 impl $crate::util::ser::SeekReadable for $name {
936                         fn read<R: $crate::io::Read + $crate::io::Seek>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
937                                 $(
938                                         _init_tlv_field_var!($field, option);
939                                 )*
940                                 let rewind = |cursor: &mut R, offset: usize| {
941                                         cursor.seek($crate::io::SeekFrom::Current(-(offset as i64))).expect("");
942                                 };
943                                 _decode_tlv_stream_range!(reader, $range, rewind, {
944                                         $(($type, $field, (option, encoding: $fieldty))),*
945                                 });
946
947                                 Ok(Self {
948                                         $(
949                                                 $field: $field
950                                         ),*
951                                 })
952                         }
953                 }
954         }
955 }
956
957 macro_rules! tlv_record_type {
958         (($type:ty, $wrapper:ident)) => { $type };
959         (($type:ty, $wrapper:ident, $encoder:ty)) => { $type };
960         ($type:ty) => { $type };
961 }
962
963 macro_rules! tlv_record_ref_type {
964         (char) => { char };
965         (u8) => { u8 };
966         ((u16, $wrapper: ident)) => { u16 };
967         ((u32, $wrapper: ident)) => { u32 };
968         ((u64, $wrapper: ident)) => { u64 };
969         (($type:ty, $wrapper:ident)) => { &'a $type };
970         (($type:ty, $wrapper:ident, $encoder:ty)) => { $encoder };
971         ($type:ty) => { &'a $type };
972 }
973
974 #[doc(hidden)]
975 #[macro_export]
976 macro_rules! _impl_writeable_tlv_based_enum_common {
977         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
978                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
979         ),* $(,)*;
980         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
981                 impl $crate::util::ser::Writeable for $st {
982                         fn write<W: $crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), $crate::io::Error> {
983                                 match self {
984                                         $($st::$variant_name { $(ref $field),* } => {
985                                                 let id: u8 = $variant_id;
986                                                 id.write(writer)?;
987                                                 $crate::write_tlv_fields!(writer, {
988                                                         $(($type, *$field, $fieldty)),*
989                                                 });
990                                         }),*
991                                         $($st::$tuple_variant_name (ref field) => {
992                                                 let id: u8 = $tuple_variant_id;
993                                                 id.write(writer)?;
994                                                 field.write(writer)?;
995                                         }),*
996                                 }
997                                 Ok(())
998                         }
999                 }
1000         }
1001 }
1002
1003 /// Implement [`Readable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and tuple
1004 /// variants stored directly.
1005 /// The format is, for example
1006 /// ```ignore
1007 /// impl_writeable_tlv_based_enum!(EnumName,
1008 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
1009 ///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, optional_vec)};
1010 ///   (2, TupleVariantA), (3, TupleVariantB),
1011 /// );
1012 /// ```
1013 /// The type is written as a single byte, followed by any variant data.
1014 /// Attempts to read an unknown type byte result in [`DecodeError::UnknownRequiredFeature`].
1015 ///
1016 /// [`Readable`]: crate::util::ser::Readable
1017 /// [`Writeable`]: crate::util::ser::Writeable
1018 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1019 #[macro_export]
1020 macro_rules! impl_writeable_tlv_based_enum {
1021         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1022                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1023         ),* $(,)*;
1024         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
1025                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1026                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1027                         $(($tuple_variant_id, $tuple_variant_name)),*);
1028
1029                 impl $crate::util::ser::Readable for $st {
1030                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
1031                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1032                                 match id {
1033                                         $($variant_id => {
1034                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1035                                                 // in the same function body. Instead, we define a closure and call it.
1036                                                 let f = || {
1037                                                         $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
1038                                                                 $(($type, $field, $fieldty)),*
1039                                                         });
1040                                                         Ok($st::$variant_name {
1041                                                                 $(
1042                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1043                                                                 ),*
1044                                                         })
1045                                                 };
1046                                                 f()
1047                                         }),*
1048                                         $($tuple_variant_id => {
1049                                                 Ok($st::$tuple_variant_name($crate::util::ser::Readable::read(reader)?))
1050                                         }),*
1051                                         _ => {
1052                                                 Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature)
1053                                         },
1054                                 }
1055                         }
1056                 }
1057         }
1058 }
1059
1060 /// Implement [`MaybeReadable`] and [`Writeable`] for an enum, with struct variants stored as TLVs and
1061 /// tuple variants stored directly.
1062 ///
1063 /// This is largely identical to [`impl_writeable_tlv_based_enum`], except that odd variants will
1064 /// return `Ok(None)` instead of `Err(`[`DecodeError::UnknownRequiredFeature`]`)`. It should generally be preferred
1065 /// when [`MaybeReadable`] is practical instead of just [`Readable`] as it provides an upgrade path for
1066 /// new variants to be added which are simply ignored by existing clients.
1067 ///
1068 /// [`MaybeReadable`]: crate::util::ser::MaybeReadable
1069 /// [`Writeable`]: crate::util::ser::Writeable
1070 /// [`DecodeError::UnknownRequiredFeature`]: crate::ln::msgs::DecodeError::UnknownRequiredFeature
1071 /// [`Readable`]: crate::util::ser::Readable
1072 #[macro_export]
1073 macro_rules! impl_writeable_tlv_based_enum_upgradable {
1074         ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
1075                 {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
1076         ),* $(,)*
1077         $(;
1078         $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
1079                 $crate::_impl_writeable_tlv_based_enum_common!($st,
1080                         $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
1081                         $($(($tuple_variant_id, $tuple_variant_name)),*)*);
1082
1083                 impl $crate::util::ser::MaybeReadable for $st {
1084                         fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Option<Self>, $crate::ln::msgs::DecodeError> {
1085                                 let id: u8 = $crate::util::ser::Readable::read(reader)?;
1086                                 match id {
1087                                         $($variant_id => {
1088                                                 // Because read_tlv_fields creates a labeled loop, we cannot call it twice
1089                                                 // in the same function body. Instead, we define a closure and call it.
1090                                                 let f = || {
1091                                                         $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
1092                                                                 $(($type, $field, $fieldty)),*
1093                                                         });
1094                                                         Ok(Some($st::$variant_name {
1095                                                                 $(
1096                                                                         $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
1097                                                                 ),*
1098                                                         }))
1099                                                 };
1100                                                 f()
1101                                         }),*
1102                                         $($($tuple_variant_id => {
1103                                                 Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
1104                                         }),*)*
1105                                         _ if id % 2 == 1 => Ok(None),
1106                                         _ => Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature),
1107                                 }
1108                         }
1109                 }
1110         }
1111 }
1112
1113 #[cfg(test)]
1114 mod tests {
1115         use crate::io::{self, Cursor};
1116         use crate::prelude::*;
1117         use crate::ln::msgs::DecodeError;
1118         use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
1119         use bitcoin::hashes::hex::FromHex;
1120         use bitcoin::secp256k1::PublicKey;
1121
1122         // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
1123         // the encoding layer in the BOLTs has no such concept, though it makes our macros easier to
1124         // work with so they're baked into the decoder. Thus, we have a few additional tests below
1125         fn tlv_reader(s: &[u8]) -> Result<(u64, u32, Option<u32>), DecodeError> {
1126                 let mut s = Cursor::new(s);
1127                 let mut a: u64 = 0;
1128                 let mut b: u32 = 0;
1129                 let mut c: Option<u32> = None;
1130                 decode_tlv_stream!(&mut s, {(2, a, required), (3, b, required), (4, c, option)});
1131                 Ok((a, b, c))
1132         }
1133
1134         #[test]
1135         fn tlv_v_short_read() {
1136                 // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
1137                 if let Err(DecodeError::ShortRead) = tlv_reader(&<Vec<u8>>::from_hex(
1138                                 concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
1139                                 ).unwrap()[..]) {
1140                 } else { panic!(); }
1141         }
1142
1143         #[test]
1144         fn tlv_types_out_of_order() {
1145                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1146                                 concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
1147                                 ).unwrap()[..]) {
1148                 } else { panic!(); }
1149                 // ...even if its some field we don't understand
1150                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1151                                 concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
1152                                 ).unwrap()[..]) {
1153                 } else { panic!(); }
1154         }
1155
1156         #[test]
1157         fn tlv_req_type_missing_or_extra() {
1158                 // It's also bad if they included even fields we don't understand
1159                 if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&<Vec<u8>>::from_hex(
1160                                 concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
1161                                 ).unwrap()[..]) {
1162                 } else { panic!(); }
1163                 // ... or if they're missing fields we need
1164                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1165                                 concat!("0100", "0208deadbeef1badbeef")
1166                                 ).unwrap()[..]) {
1167                 } else { panic!(); }
1168                 // ... even if that field is even
1169                 if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
1170                                 concat!("0304deadbeef", "0500")
1171                                 ).unwrap()[..]) {
1172                 } else { panic!(); }
1173         }
1174
1175         #[test]
1176         fn tlv_simple_good_cases() {
1177                 assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
1178                                 concat!("0208deadbeef1badbeef", "03041bad1dea")
1179                                 ).unwrap()[..]).unwrap(),
1180                         (0xdeadbeef1badbeef, 0x1bad1dea, None));
1181                 assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
1182                                 concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
1183                                 ).unwrap()[..]).unwrap(),
1184                         (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
1185         }
1186
1187         #[derive(Debug, PartialEq)]
1188         struct TestUpgradable {
1189                 a: u32,
1190                 b: u32,
1191                 c: Option<u32>,
1192         }
1193
1194         fn upgradable_tlv_reader(s: &[u8]) -> Result<Option<TestUpgradable>, DecodeError> {
1195                 let mut s = Cursor::new(s);
1196                 let mut a = 0;
1197                 let mut b = 0;
1198                 let mut c: Option<u32> = None;
1199                 decode_tlv_stream!(&mut s, {(2, a, upgradable_required), (3, b, upgradable_required), (4, c, upgradable_option)});
1200                 Ok(Some(TestUpgradable { a, b, c, }))
1201         }
1202
1203         #[test]
1204         fn upgradable_tlv_simple_good_cases() {
1205                 assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1206                         concat!("0204deadbeef", "03041bad1dea", "0404deadbeef")
1207                 ).unwrap()[..]).unwrap(),
1208                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: Some(0xdeadbeef) }));
1209
1210                 assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1211                         concat!("0204deadbeef", "03041bad1dea")
1212                 ).unwrap()[..]).unwrap(),
1213                 Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: None}));
1214         }
1215
1216         #[test]
1217         fn missing_required_upgradable() {
1218                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1219                         concat!("0100", "0204deadbeef")
1220                         ).unwrap()[..]) {
1221                 } else { panic!(); }
1222                 if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
1223                         concat!("0100", "03041bad1dea")
1224                 ).unwrap()[..]) {
1225                 } else { panic!(); }
1226         }
1227
1228         // BOLT TLV test cases
1229         fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
1230                 let mut s = Cursor::new(s);
1231                 let mut tlv1: Option<HighZeroBytesDroppedBigSize<u64>> = None;
1232                 let mut tlv2: Option<u64> = None;
1233                 let mut tlv3: Option<(PublicKey, u64, u64)> = None;
1234                 let mut tlv4: Option<u16> = None;
1235                 decode_tlv_stream!(&mut s, {(1, tlv1, option), (2, tlv2, option), (3, tlv3, option), (254, tlv4, option)});
1236                 Ok((tlv1, tlv2, tlv3, tlv4))
1237         }
1238
1239         #[test]
1240         fn bolt_tlv_bogus_stream() {
1241                 macro_rules! do_test {
1242                         ($stream: expr, $reason: ident) => {
1243                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1244                                 } else { panic!(); }
1245                         }
1246                 }
1247
1248                 // TLVs from the BOLT test cases which should not decode as either n1 or n2
1249                 do_test!(concat!("fd01"), ShortRead);
1250                 do_test!(concat!("fd0001", "00"), InvalidValue);
1251                 do_test!(concat!("fd0101"), ShortRead);
1252                 do_test!(concat!("0f", "fd"), ShortRead);
1253                 do_test!(concat!("0f", "fd26"), ShortRead);
1254                 do_test!(concat!("0f", "fd2602"), ShortRead);
1255                 do_test!(concat!("0f", "fd0001", "00"), InvalidValue);
1256                 do_test!(concat!("0f", "fd0201", "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"), ShortRead);
1257
1258                 do_test!(concat!("12", "00"), UnknownRequiredFeature);
1259                 do_test!(concat!("fd0102", "00"), UnknownRequiredFeature);
1260                 do_test!(concat!("fe01000002", "00"), UnknownRequiredFeature);
1261                 do_test!(concat!("ff0100000000000002", "00"), UnknownRequiredFeature);
1262         }
1263
1264         #[test]
1265         fn bolt_tlv_bogus_n1_stream() {
1266                 macro_rules! do_test {
1267                         ($stream: expr, $reason: ident) => {
1268                                 if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1269                                 } else { panic!(); }
1270                         }
1271                 }
1272
1273                 // TLVs from the BOLT test cases which should not decode as n1
1274                 do_test!(concat!("01", "09", "ffffffffffffffffff"), InvalidValue);
1275                 do_test!(concat!("01", "01", "00"), InvalidValue);
1276                 do_test!(concat!("01", "02", "0001"), InvalidValue);
1277                 do_test!(concat!("01", "03", "000100"), InvalidValue);
1278                 do_test!(concat!("01", "04", "00010000"), InvalidValue);
1279                 do_test!(concat!("01", "05", "0001000000"), InvalidValue);
1280                 do_test!(concat!("01", "06", "000100000000"), InvalidValue);
1281                 do_test!(concat!("01", "07", "00010000000000"), InvalidValue);
1282                 do_test!(concat!("01", "08", "0001000000000000"), InvalidValue);
1283                 do_test!(concat!("02", "07", "01010101010101"), ShortRead);
1284                 do_test!(concat!("02", "09", "010101010101010101"), InvalidValue);
1285                 do_test!(concat!("03", "21", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb"), ShortRead);
1286                 do_test!(concat!("03", "29", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001"), ShortRead);
1287                 do_test!(concat!("03", "30", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb000000000000000100000000000001"), ShortRead);
1288                 do_test!(concat!("03", "31", "043da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"), InvalidValue);
1289                 do_test!(concat!("03", "32", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb0000000000000001000000000000000001"), InvalidValue);
1290                 do_test!(concat!("fd00fe", "00"), ShortRead);
1291                 do_test!(concat!("fd00fe", "01", "01"), ShortRead);
1292                 do_test!(concat!("fd00fe", "03", "010101"), InvalidValue);
1293                 do_test!(concat!("00", "00"), UnknownRequiredFeature);
1294
1295                 do_test!(concat!("02", "08", "0000000000000226", "01", "01", "2a"), InvalidValue);
1296                 do_test!(concat!("02", "08", "0000000000000231", "02", "08", "0000000000000451"), InvalidValue);
1297                 do_test!(concat!("1f", "00", "0f", "01", "2a"), InvalidValue);
1298                 do_test!(concat!("1f", "00", "1f", "01", "2a"), InvalidValue);
1299
1300                 // The last BOLT test modified to not require creating a new decoder for one trivial test.
1301                 do_test!(concat!("ffffffffffffffffff", "00", "01", "00"), InvalidValue);
1302         }
1303
1304         #[test]
1305         fn bolt_tlv_valid_n1_stream() {
1306                 macro_rules! do_test {
1307                         ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
1308                                 if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
1309                                         assert_eq!(tlv1.map(|v| v.0), $tlv1);
1310                                         assert_eq!(tlv2, $tlv2);
1311                                         assert_eq!(tlv3, $tlv3);
1312                                         assert_eq!(tlv4, $tlv4);
1313                                 } else { panic!(); }
1314                         }
1315                 }
1316
1317                 do_test!(concat!(""), None, None, None, None);
1318                 do_test!(concat!("21", "00"), None, None, None, None);
1319                 do_test!(concat!("fd0201", "00"), None, None, None, None);
1320                 do_test!(concat!("fd00fd", "00"), None, None, None, None);
1321                 do_test!(concat!("fd00ff", "00"), None, None, None, None);
1322                 do_test!(concat!("fe02000001", "00"), None, None, None, None);
1323                 do_test!(concat!("ff0200000000000001", "00"), None, None, None, None);
1324
1325                 do_test!(concat!("01", "00"), Some(0), None, None, None);
1326                 do_test!(concat!("01", "01", "01"), Some(1), None, None, None);
1327                 do_test!(concat!("01", "02", "0100"), Some(256), None, None, None);
1328                 do_test!(concat!("01", "03", "010000"), Some(65536), None, None, None);
1329                 do_test!(concat!("01", "04", "01000000"), Some(16777216), None, None, None);
1330                 do_test!(concat!("01", "05", "0100000000"), Some(4294967296), None, None, None);
1331                 do_test!(concat!("01", "06", "010000000000"), Some(1099511627776), None, None, None);
1332                 do_test!(concat!("01", "07", "01000000000000"), Some(281474976710656), None, None, None);
1333                 do_test!(concat!("01", "08", "0100000000000000"), Some(72057594037927936), None, None, None);
1334                 do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
1335                 do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
1336                         None, None, Some((
1337                                 PublicKey::from_slice(&<Vec<u8>>::from_hex("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
1338                         None);
1339                 do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
1340         }
1341
1342         fn do_simple_test_tlv_write() -> Result<(), io::Error> {
1343                 let mut stream = VecWriter(Vec::new());
1344
1345                 stream.0.clear();
1346                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
1347                 assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
1348
1349                 stream.0.clear();
1350                 _encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
1351                 assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
1352
1353                 stream.0.clear();
1354                 _encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
1355                 assert_eq!(stream.0, <Vec<u8>>::from_hex("040402abcd").unwrap());
1356
1357                 stream.0.clear();
1358                 _encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
1359                 assert_eq!(stream.0, <Vec<u8>>::from_hex("06fd00ff02abcd").unwrap());
1360
1361                 stream.0.clear();
1362                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1363                 assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
1364
1365                 stream.0.clear();
1366                 _encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
1367                 assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
1368
1369                 Ok(())
1370         }
1371
1372         #[test]
1373         fn simple_test_tlv_write() {
1374                 do_simple_test_tlv_write().unwrap();
1375         }
1376 }