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Merge pull request #2226 from alecchendev/2023-04-persist-network-graph-on-rgs
[rust-lightning] / lightning / src / util / ser.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 //! A very simple serialization framework which is used to serialize/deserialize messages as well
11 //! as [`ChannelManager`]s and [`ChannelMonitor`]s.
12 //!
13 //! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
14 //! [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
15
16 use crate::prelude::*;
17 use crate::io::{self, Read, Seek, Write};
18 use crate::io_extras::{copy, sink};
19 use core::hash::Hash;
20 use crate::sync::Mutex;
21 use core::cmp;
22 use core::convert::TryFrom;
23 use core::ops::Deref;
24
25 use alloc::collections::BTreeMap;
26
27 use bitcoin::secp256k1::{PublicKey, SecretKey};
28 use bitcoin::secp256k1::constants::{PUBLIC_KEY_SIZE, SECRET_KEY_SIZE, COMPACT_SIGNATURE_SIZE, SCHNORR_SIGNATURE_SIZE};
29 use bitcoin::secp256k1::ecdsa;
30 use bitcoin::secp256k1::schnorr;
31 use bitcoin::blockdata::constants::ChainHash;
32 use bitcoin::blockdata::script::{self, Script};
33 use bitcoin::blockdata::transaction::{OutPoint, Transaction, TxOut};
34 use bitcoin::{consensus, Witness};
35 use bitcoin::consensus::Encodable;
36 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
37 use bitcoin::hash_types::{Txid, BlockHash};
38 use core::marker::Sized;
39 use core::time::Duration;
40 use crate::ln::msgs::DecodeError;
41 #[cfg(taproot)]
42 use crate::ln::msgs::PartialSignatureWithNonce;
43 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
44
45 use crate::util::byte_utils::{be48_to_array, slice_to_be48};
46
47 /// serialization buffer size
48 pub const MAX_BUF_SIZE: usize = 64 * 1024;
49
50 /// A simplified version of [`std::io::Write`] that exists largely for backwards compatibility.
51 /// An impl is provided for any type that also impls [`std::io::Write`].
52 ///
53 /// This is not exported to bindings users as we only export serialization to/from byte arrays instead
54 pub trait Writer {
55         /// Writes the given buf out. See std::io::Write::write_all for more
56         fn write_all(&mut self, buf: &[u8]) -> Result<(), io::Error>;
57 }
58
59 impl<W: Write> Writer for W {
60         #[inline]
61         fn write_all(&mut self, buf: &[u8]) -> Result<(), io::Error> {
62                 <Self as io::Write>::write_all(self, buf)
63         }
64 }
65
66 pub(crate) struct WriterWriteAdaptor<'a, W: Writer + 'a>(pub &'a mut W);
67 impl<'a, W: Writer + 'a> Write for WriterWriteAdaptor<'a, W> {
68         #[inline]
69         fn write_all(&mut self, buf: &[u8]) -> Result<(), io::Error> {
70                 self.0.write_all(buf)
71         }
72         #[inline]
73         fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> {
74                 self.0.write_all(buf)?;
75                 Ok(buf.len())
76         }
77         #[inline]
78         fn flush(&mut self) -> Result<(), io::Error> {
79                 Ok(())
80         }
81 }
82
83 pub(crate) struct VecWriter(pub Vec<u8>);
84 impl Writer for VecWriter {
85         #[inline]
86         fn write_all(&mut self, buf: &[u8]) -> Result<(), io::Error> {
87                 self.0.extend_from_slice(buf);
88                 Ok(())
89         }
90 }
91
92 /// Writer that only tracks the amount of data written - useful if you need to calculate the length
93 /// of some data when serialized but don't yet need the full data.
94 ///
95 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
96 pub struct LengthCalculatingWriter(pub usize);
97 impl Writer for LengthCalculatingWriter {
98         #[inline]
99         fn write_all(&mut self, buf: &[u8]) -> Result<(), io::Error> {
100                 self.0 += buf.len();
101                 Ok(())
102         }
103 }
104
105 /// Essentially [`std::io::Take`] but a bit simpler and with a method to walk the underlying stream
106 /// forward to ensure we always consume exactly the fixed length specified.
107 ///
108 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
109 pub struct FixedLengthReader<R: Read> {
110         read: R,
111         bytes_read: u64,
112         total_bytes: u64,
113 }
114 impl<R: Read> FixedLengthReader<R> {
115         /// Returns a new [`FixedLengthReader`].
116         pub fn new(read: R, total_bytes: u64) -> Self {
117                 Self { read, bytes_read: 0, total_bytes }
118         }
119
120         /// Returns whether some bytes are remaining or not.
121         #[inline]
122         pub fn bytes_remain(&mut self) -> bool {
123                 self.bytes_read != self.total_bytes
124         }
125
126         /// Consumes the remaining bytes.
127         #[inline]
128         pub fn eat_remaining(&mut self) -> Result<(), DecodeError> {
129                 copy(self, &mut sink()).unwrap();
130                 if self.bytes_read != self.total_bytes {
131                         Err(DecodeError::ShortRead)
132                 } else {
133                         Ok(())
134                 }
135         }
136 }
137 impl<R: Read> Read for FixedLengthReader<R> {
138         #[inline]
139         fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
140                 if self.total_bytes == self.bytes_read {
141                         Ok(0)
142                 } else {
143                         let read_len = cmp::min(dest.len() as u64, self.total_bytes - self.bytes_read);
144                         match self.read.read(&mut dest[0..(read_len as usize)]) {
145                                 Ok(v) => {
146                                         self.bytes_read += v as u64;
147                                         Ok(v)
148                                 },
149                                 Err(e) => Err(e),
150                         }
151                 }
152         }
153 }
154
155 impl<R: Read> LengthRead for FixedLengthReader<R> {
156         #[inline]
157         fn total_bytes(&self) -> u64 {
158                 self.total_bytes
159         }
160 }
161
162 /// A [`Read`] implementation which tracks whether any bytes have been read at all. This allows us to distinguish
163 /// between "EOF reached before we started" and "EOF reached mid-read".
164 ///
165 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
166 pub struct ReadTrackingReader<R: Read> {
167         read: R,
168         /// Returns whether we have read from this reader or not yet.
169         pub have_read: bool,
170 }
171 impl<R: Read> ReadTrackingReader<R> {
172         /// Returns a new [`ReadTrackingReader`].
173         pub fn new(read: R) -> Self {
174                 Self { read, have_read: false }
175         }
176 }
177 impl<R: Read> Read for ReadTrackingReader<R> {
178         #[inline]
179         fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
180                 match self.read.read(dest) {
181                         Ok(0) => Ok(0),
182                         Ok(len) => {
183                                 self.have_read = true;
184                                 Ok(len)
185                         },
186                         Err(e) => Err(e),
187                 }
188         }
189 }
190
191 /// A trait that various LDK types implement allowing them to be written out to a [`Writer`].
192 ///
193 /// This is not exported to bindings users as we only export serialization to/from byte arrays instead
194 pub trait Writeable {
195         /// Writes `self` out to the given [`Writer`].
196         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error>;
197
198         /// Writes `self` out to a `Vec<u8>`.
199         fn encode(&self) -> Vec<u8> {
200                 let mut msg = VecWriter(Vec::new());
201                 self.write(&mut msg).unwrap();
202                 msg.0
203         }
204
205         /// Writes `self` out to a `Vec<u8>`.
206         #[cfg(test)]
207         fn encode_with_len(&self) -> Vec<u8> {
208                 let mut msg = VecWriter(Vec::new());
209                 0u16.write(&mut msg).unwrap();
210                 self.write(&mut msg).unwrap();
211                 let len = msg.0.len();
212                 msg.0[..2].copy_from_slice(&(len as u16 - 2).to_be_bytes());
213                 msg.0
214         }
215
216         /// Gets the length of this object after it has been serialized. This can be overridden to
217         /// optimize cases where we prepend an object with its length.
218         // Note that LLVM optimizes this away in most cases! Check that it isn't before you override!
219         #[inline]
220         fn serialized_length(&self) -> usize {
221                 let mut len_calc = LengthCalculatingWriter(0);
222                 self.write(&mut len_calc).expect("No in-memory data may fail to serialize");
223                 len_calc.0
224         }
225 }
226
227 impl<'a, T: Writeable> Writeable for &'a T {
228         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> { (*self).write(writer) }
229 }
230
231 /// A trait that various LDK types implement allowing them to be read in from a [`Read`].
232 ///
233 /// This is not exported to bindings users as we only export serialization to/from byte arrays instead
234 pub trait Readable
235         where Self: Sized
236 {
237         /// Reads a `Self` in from the given [`Read`].
238         fn read<R: Read>(reader: &mut R) -> Result<Self, DecodeError>;
239 }
240
241 /// A trait that various LDK types implement allowing them to be read in from a
242 /// [`Read`]` + `[`Seek`].
243 pub(crate) trait SeekReadable where Self: Sized {
244         /// Reads a `Self` in from the given [`Read`].
245         fn read<R: Read + Seek>(reader: &mut R) -> Result<Self, DecodeError>;
246 }
247
248 /// A trait that various higher-level LDK types implement allowing them to be read in
249 /// from a [`Read`] given some additional set of arguments which is required to deserialize.
250 ///
251 /// This is not exported to bindings users as we only export serialization to/from byte arrays instead
252 pub trait ReadableArgs<P>
253         where Self: Sized
254 {
255         /// Reads a `Self` in from the given [`Read`].
256         fn read<R: Read>(reader: &mut R, params: P) -> Result<Self, DecodeError>;
257 }
258
259 /// A [`std::io::Read`] that also provides the total bytes available to be read.
260 pub(crate) trait LengthRead: Read {
261         /// The total number of bytes available to be read.
262         fn total_bytes(&self) -> u64;
263 }
264
265 /// A trait that various higher-level LDK types implement allowing them to be read in
266 /// from a Read given some additional set of arguments which is required to deserialize, requiring
267 /// the implementer to provide the total length of the read.
268 pub(crate) trait LengthReadableArgs<P> where Self: Sized
269 {
270         /// Reads a `Self` in from the given [`LengthRead`].
271         fn read<R: LengthRead>(reader: &mut R, params: P) -> Result<Self, DecodeError>;
272 }
273
274 /// A trait that various higher-level LDK types implement allowing them to be read in
275 /// from a [`Read`], requiring the implementer to provide the total length of the read.
276 pub(crate) trait LengthReadable where Self: Sized
277 {
278         /// Reads a `Self` in from the given [`LengthRead`].
279         fn read<R: LengthRead>(reader: &mut R) -> Result<Self, DecodeError>;
280 }
281
282 /// A trait that various LDK types implement allowing them to (maybe) be read in from a [`Read`].
283 ///
284 /// This is not exported to bindings users as we only export serialization to/from byte arrays instead
285 pub trait MaybeReadable
286         where Self: Sized
287 {
288         /// Reads a `Self` in from the given [`Read`].
289         fn read<R: Read>(reader: &mut R) -> Result<Option<Self>, DecodeError>;
290 }
291
292 impl<T: Readable> MaybeReadable for T {
293         #[inline]
294         fn read<R: Read>(reader: &mut R) -> Result<Option<T>, DecodeError> {
295                 Ok(Some(Readable::read(reader)?))
296         }
297 }
298
299 /// Wrapper to read a required (non-optional) TLV record.
300 ///
301 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
302 pub struct RequiredWrapper<T>(pub Option<T>);
303 impl<T: Readable> Readable for RequiredWrapper<T> {
304         #[inline]
305         fn read<R: Read>(reader: &mut R) -> Result<Self, DecodeError> {
306                 Ok(Self(Some(Readable::read(reader)?)))
307         }
308 }
309 impl<A, T: ReadableArgs<A>> ReadableArgs<A> for RequiredWrapper<T> {
310         #[inline]
311         fn read<R: Read>(reader: &mut R, args: A) -> Result<Self, DecodeError> {
312                 Ok(Self(Some(ReadableArgs::read(reader, args)?)))
313         }
314 }
315 /// When handling `default_values`, we want to map the default-value T directly
316 /// to a `RequiredWrapper<T>` in a way that works for `field: T = t;` as
317 /// well. Thus, we assume `Into<T> for T` does nothing and use that.
318 impl<T> From<T> for RequiredWrapper<T> {
319         fn from(t: T) -> RequiredWrapper<T> { RequiredWrapper(Some(t)) }
320 }
321
322 /// Wrapper to read a required (non-optional) TLV record that may have been upgraded without
323 /// backwards compat.
324 ///
325 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
326 pub struct UpgradableRequired<T: MaybeReadable>(pub Option<T>);
327 impl<T: MaybeReadable> MaybeReadable for UpgradableRequired<T> {
328         #[inline]
329         fn read<R: Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
330                 let tlv = MaybeReadable::read(reader)?;
331                 if let Some(tlv) = tlv { return Ok(Some(Self(Some(tlv)))) }
332                 Ok(None)
333         }
334 }
335
336 pub(crate) struct U48(pub u64);
337 impl Writeable for U48 {
338         #[inline]
339         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
340                 writer.write_all(&be48_to_array(self.0))
341         }
342 }
343 impl Readable for U48 {
344         #[inline]
345         fn read<R: Read>(reader: &mut R) -> Result<U48, DecodeError> {
346                 let mut buf = [0; 6];
347                 reader.read_exact(&mut buf)?;
348                 Ok(U48(slice_to_be48(&buf)))
349         }
350 }
351
352 /// Lightning TLV uses a custom variable-length integer called `BigSize`. It is similar to Bitcoin's
353 /// variable-length integers except that it is serialized in big-endian instead of little-endian.
354 ///
355 /// Like Bitcoin's variable-length integer, it exhibits ambiguity in that certain values can be
356 /// encoded in several different ways, which we must check for at deserialization-time. Thus, if
357 /// you're looking for an example of a variable-length integer to use for your own project, move
358 /// along, this is a rather poor design.
359 pub struct BigSize(pub u64);
360 impl Writeable for BigSize {
361         #[inline]
362         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
363                 match self.0 {
364                         0...0xFC => {
365                                 (self.0 as u8).write(writer)
366                         },
367                         0xFD...0xFFFF => {
368                                 0xFDu8.write(writer)?;
369                                 (self.0 as u16).write(writer)
370                         },
371                         0x10000...0xFFFFFFFF => {
372                                 0xFEu8.write(writer)?;
373                                 (self.0 as u32).write(writer)
374                         },
375                         _ => {
376                                 0xFFu8.write(writer)?;
377                                 (self.0 as u64).write(writer)
378                         },
379                 }
380         }
381 }
382 impl Readable for BigSize {
383         #[inline]
384         fn read<R: Read>(reader: &mut R) -> Result<BigSize, DecodeError> {
385                 let n: u8 = Readable::read(reader)?;
386                 match n {
387                         0xFF => {
388                                 let x: u64 = Readable::read(reader)?;
389                                 if x < 0x100000000 {
390                                         Err(DecodeError::InvalidValue)
391                                 } else {
392                                         Ok(BigSize(x))
393                                 }
394                         }
395                         0xFE => {
396                                 let x: u32 = Readable::read(reader)?;
397                                 if x < 0x10000 {
398                                         Err(DecodeError::InvalidValue)
399                                 } else {
400                                         Ok(BigSize(x as u64))
401                                 }
402                         }
403                         0xFD => {
404                                 let x: u16 = Readable::read(reader)?;
405                                 if x < 0xFD {
406                                         Err(DecodeError::InvalidValue)
407                                 } else {
408                                         Ok(BigSize(x as u64))
409                                 }
410                         }
411                         n => Ok(BigSize(n as u64))
412                 }
413         }
414 }
415
416 /// The lightning protocol uses u16s for lengths in most cases. As our serialization framework
417 /// primarily targets that, we must as well. However, because we may serialize objects that have
418 /// more than 65K entries, we need to be able to store larger values. Thus, we define a variable
419 /// length integer here that is backwards-compatible for values < 0xffff. We treat 0xffff as
420 /// "read eight more bytes".
421 ///
422 /// To ensure we only have one valid encoding per value, we add 0xffff to values written as eight
423 /// bytes. Thus, 0xfffe is serialized as 0xfffe, whereas 0xffff is serialized as
424 /// 0xffff0000000000000000 (i.e. read-eight-bytes then zero).
425 struct CollectionLength(pub u64);
426 impl Writeable for CollectionLength {
427         #[inline]
428         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
429                 if self.0 < 0xffff {
430                         (self.0 as u16).write(writer)
431                 } else {
432                         0xffffu16.write(writer)?;
433                         (self.0 - 0xffff).write(writer)
434                 }
435         }
436 }
437
438 impl Readable for CollectionLength {
439         #[inline]
440         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
441                 let mut val: u64 = <u16 as Readable>::read(r)? as u64;
442                 if val == 0xffff {
443                         val = <u64 as Readable>::read(r)?
444                                 .checked_add(0xffff).ok_or(DecodeError::InvalidValue)?;
445                 }
446                 Ok(CollectionLength(val))
447         }
448 }
449
450 /// In TLV we occasionally send fields which only consist of, or potentially end with, a
451 /// variable-length integer which is simply truncated by skipping high zero bytes. This type
452 /// encapsulates such integers implementing [`Readable`]/[`Writeable`] for them.
453 #[cfg_attr(test, derive(PartialEq, Eq, Debug))]
454 pub(crate) struct HighZeroBytesDroppedBigSize<T>(pub T);
455
456 macro_rules! impl_writeable_primitive {
457         ($val_type:ty, $len: expr) => {
458                 impl Writeable for $val_type {
459                         #[inline]
460                         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
461                                 writer.write_all(&self.to_be_bytes())
462                         }
463                 }
464                 impl Writeable for HighZeroBytesDroppedBigSize<$val_type> {
465                         #[inline]
466                         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
467                                 // Skip any full leading 0 bytes when writing (in BE):
468                                 writer.write_all(&self.0.to_be_bytes()[(self.0.leading_zeros()/8) as usize..$len])
469                         }
470                 }
471                 impl Readable for $val_type {
472                         #[inline]
473                         fn read<R: Read>(reader: &mut R) -> Result<$val_type, DecodeError> {
474                                 let mut buf = [0; $len];
475                                 reader.read_exact(&mut buf)?;
476                                 Ok(<$val_type>::from_be_bytes(buf))
477                         }
478                 }
479                 impl Readable for HighZeroBytesDroppedBigSize<$val_type> {
480                         #[inline]
481                         fn read<R: Read>(reader: &mut R) -> Result<HighZeroBytesDroppedBigSize<$val_type>, DecodeError> {
482                                 // We need to accept short reads (read_len == 0) as "EOF" and handle them as simply
483                                 // the high bytes being dropped. To do so, we start reading into the middle of buf
484                                 // and then convert the appropriate number of bytes with extra high bytes out of
485                                 // buf.
486                                 let mut buf = [0; $len*2];
487                                 let mut read_len = reader.read(&mut buf[$len..])?;
488                                 let mut total_read_len = read_len;
489                                 while read_len != 0 && total_read_len != $len {
490                                         read_len = reader.read(&mut buf[($len + total_read_len)..])?;
491                                         total_read_len += read_len;
492                                 }
493                                 if total_read_len == 0 || buf[$len] != 0 {
494                                         let first_byte = $len - ($len - total_read_len);
495                                         let mut bytes = [0; $len];
496                                         bytes.copy_from_slice(&buf[first_byte..first_byte + $len]);
497                                         Ok(HighZeroBytesDroppedBigSize(<$val_type>::from_be_bytes(bytes)))
498                                 } else {
499                                         // If the encoding had extra zero bytes, return a failure even though we know
500                                         // what they meant (as the TLV test vectors require this)
501                                         Err(DecodeError::InvalidValue)
502                                 }
503                         }
504                 }
505                 impl From<$val_type> for HighZeroBytesDroppedBigSize<$val_type> {
506                         fn from(val: $val_type) -> Self { Self(val) }
507                 }
508         }
509 }
510
511 impl_writeable_primitive!(u128, 16);
512 impl_writeable_primitive!(u64, 8);
513 impl_writeable_primitive!(u32, 4);
514 impl_writeable_primitive!(u16, 2);
515 impl_writeable_primitive!(i64, 8);
516 impl_writeable_primitive!(i32, 4);
517 impl_writeable_primitive!(i16, 2);
518 impl_writeable_primitive!(i8, 1);
519
520 impl Writeable for u8 {
521         #[inline]
522         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
523                 writer.write_all(&[*self])
524         }
525 }
526 impl Readable for u8 {
527         #[inline]
528         fn read<R: Read>(reader: &mut R) -> Result<u8, DecodeError> {
529                 let mut buf = [0; 1];
530                 reader.read_exact(&mut buf)?;
531                 Ok(buf[0])
532         }
533 }
534
535 impl Writeable for bool {
536         #[inline]
537         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
538                 writer.write_all(&[if *self {1} else {0}])
539         }
540 }
541 impl Readable for bool {
542         #[inline]
543         fn read<R: Read>(reader: &mut R) -> Result<bool, DecodeError> {
544                 let mut buf = [0; 1];
545                 reader.read_exact(&mut buf)?;
546                 if buf[0] != 0 && buf[0] != 1 {
547                         return Err(DecodeError::InvalidValue);
548                 }
549                 Ok(buf[0] == 1)
550         }
551 }
552
553 // u8 arrays
554 macro_rules! impl_array {
555         ( $size:expr ) => (
556                 impl Writeable for [u8; $size]
557                 {
558                         #[inline]
559                         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
560                                 w.write_all(self)
561                         }
562                 }
563
564                 impl Readable for [u8; $size]
565                 {
566                         #[inline]
567                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
568                                 let mut buf = [0u8; $size];
569                                 r.read_exact(&mut buf)?;
570                                 Ok(buf)
571                         }
572                 }
573         );
574 }
575
576 impl_array!(3); // for rgb, ISO 4712 code
577 impl_array!(4); // for IPv4
578 impl_array!(12); // for OnionV2
579 impl_array!(16); // for IPv6
580 impl_array!(32); // for channel id & hmac
581 impl_array!(PUBLIC_KEY_SIZE); // for PublicKey
582 impl_array!(64); // for ecdsa::Signature and schnorr::Signature
583 impl_array!(66); // for MuSig2 nonces
584 impl_array!(1300); // for OnionPacket.hop_data
585
586 impl Writeable for [u16; 8] {
587         #[inline]
588         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
589                 for v in self.iter() {
590                         w.write_all(&v.to_be_bytes())?
591                 }
592                 Ok(())
593         }
594 }
595
596 impl Readable for [u16; 8] {
597         #[inline]
598         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
599                 let mut buf = [0u8; 16];
600                 r.read_exact(&mut buf)?;
601                 let mut res = [0u16; 8];
602                 for (idx, v) in res.iter_mut().enumerate() {
603                         *v = (buf[idx*2] as u16) << 8 | (buf[idx*2 + 1] as u16)
604                 }
605                 Ok(res)
606         }
607 }
608
609 /// A type for variable-length values within TLV record where the length is encoded as part of the record.
610 /// Used to prevent encoding the length twice.
611 ///
612 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
613 pub struct WithoutLength<T>(pub T);
614
615 impl Writeable for WithoutLength<&String> {
616         #[inline]
617         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
618                 w.write_all(self.0.as_bytes())
619         }
620 }
621 impl Readable for WithoutLength<String> {
622         #[inline]
623         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
624                 let v: WithoutLength<Vec<u8>> = Readable::read(r)?;
625                 Ok(Self(String::from_utf8(v.0).map_err(|_| DecodeError::InvalidValue)?))
626         }
627 }
628 impl<'a> From<&'a String> for WithoutLength<&'a String> {
629         fn from(s: &'a String) -> Self { Self(s) }
630 }
631
632 impl<'a, T: Writeable> Writeable for WithoutLength<&'a Vec<T>> {
633         #[inline]
634         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
635                 for ref v in self.0.iter() {
636                         v.write(writer)?;
637                 }
638                 Ok(())
639         }
640 }
641
642 impl<T: MaybeReadable> Readable for WithoutLength<Vec<T>> {
643         #[inline]
644         fn read<R: Read>(mut reader: &mut R) -> Result<Self, DecodeError> {
645                 let mut values = Vec::new();
646                 loop {
647                         let mut track_read = ReadTrackingReader::new(&mut reader);
648                         match MaybeReadable::read(&mut track_read) {
649                                 Ok(Some(v)) => { values.push(v); },
650                                 Ok(None) => { },
651                                 // If we failed to read any bytes at all, we reached the end of our TLV
652                                 // stream and have simply exhausted all entries.
653                                 Err(ref e) if e == &DecodeError::ShortRead && !track_read.have_read => break,
654                                 Err(e) => return Err(e),
655                         }
656                 }
657                 Ok(Self(values))
658         }
659 }
660 impl<'a, T> From<&'a Vec<T>> for WithoutLength<&'a Vec<T>> {
661         fn from(v: &'a Vec<T>) -> Self { Self(v) }
662 }
663
664 impl Writeable for WithoutLength<&Script> {
665         #[inline]
666         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
667                 writer.write_all(self.0.as_bytes())
668         }
669 }
670
671 impl Readable for WithoutLength<Script> {
672         #[inline]
673         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
674                 let v: WithoutLength<Vec<u8>> = Readable::read(r)?;
675                 Ok(WithoutLength(script::Builder::from(v.0).into_script()))
676         }
677 }
678
679 #[derive(Debug)]
680 pub(crate) struct Iterable<'a, I: Iterator<Item = &'a T> + Clone, T: 'a>(pub I);
681
682 impl<'a, I: Iterator<Item = &'a T> + Clone, T: 'a + Writeable> Writeable for Iterable<'a, I, T> {
683         #[inline]
684         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
685                 for ref v in self.0.clone() {
686                         v.write(writer)?;
687                 }
688                 Ok(())
689         }
690 }
691
692 #[cfg(test)]
693 impl<'a, I: Iterator<Item = &'a T> + Clone, T: 'a + PartialEq> PartialEq for Iterable<'a, I, T> {
694         fn eq(&self, other: &Self) -> bool {
695                 self.0.clone().collect::<Vec<_>>() == other.0.clone().collect::<Vec<_>>()
696         }
697 }
698
699 macro_rules! impl_for_map {
700         ($ty: ident, $keybound: ident, $constr: expr) => {
701                 impl<K, V> Writeable for $ty<K, V>
702                         where K: Writeable + Eq + $keybound, V: Writeable
703                 {
704                         #[inline]
705                         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
706                                 CollectionLength(self.len() as u64).write(w)?;
707                                 for (key, value) in self.iter() {
708                                         key.write(w)?;
709                                         value.write(w)?;
710                                 }
711                                 Ok(())
712                         }
713                 }
714
715                 impl<K, V> Readable for $ty<K, V>
716                         where K: Readable + Eq + $keybound, V: MaybeReadable
717                 {
718                         #[inline]
719                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
720                                 let len: CollectionLength = Readable::read(r)?;
721                                 let mut ret = $constr(len.0 as usize);
722                                 for _ in 0..len.0 {
723                                         let k = K::read(r)?;
724                                         let v_opt = V::read(r)?;
725                                         if let Some(v) = v_opt {
726                                                 if ret.insert(k, v).is_some() {
727                                                         return Err(DecodeError::InvalidValue);
728                                                 }
729                                         }
730                                 }
731                                 Ok(ret)
732                         }
733                 }
734         }
735 }
736
737 impl_for_map!(BTreeMap, Ord, |_| BTreeMap::new());
738 impl_for_map!(HashMap, Hash, |len| HashMap::with_capacity(len));
739
740 // HashSet
741 impl<T> Writeable for HashSet<T>
742 where T: Writeable + Eq + Hash
743 {
744         #[inline]
745         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
746                 CollectionLength(self.len() as u64).write(w)?;
747                 for item in self.iter() {
748                         item.write(w)?;
749                 }
750                 Ok(())
751         }
752 }
753
754 impl<T> Readable for HashSet<T>
755 where T: Readable + Eq + Hash
756 {
757         #[inline]
758         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
759                 let len: CollectionLength = Readable::read(r)?;
760                 let mut ret = HashSet::with_capacity(cmp::min(len.0 as usize, MAX_BUF_SIZE / core::mem::size_of::<T>()));
761                 for _ in 0..len.0 {
762                         if !ret.insert(T::read(r)?) {
763                                 return Err(DecodeError::InvalidValue)
764                         }
765                 }
766                 Ok(ret)
767         }
768 }
769
770 // Vectors
771 macro_rules! impl_writeable_for_vec {
772         ($ty: ty $(, $name: ident)*) => {
773                 impl<$($name : Writeable),*> Writeable for Vec<$ty> {
774                         #[inline]
775                         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
776                                 CollectionLength(self.len() as u64).write(w)?;
777                                 for elem in self.iter() {
778                                         elem.write(w)?;
779                                 }
780                                 Ok(())
781                         }
782                 }
783         }
784 }
785 macro_rules! impl_readable_for_vec {
786         ($ty: ty $(, $name: ident)*) => {
787                 impl<$($name : Readable),*> Readable for Vec<$ty> {
788                         #[inline]
789                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
790                                 let len: CollectionLength = Readable::read(r)?;
791                                 let mut ret = Vec::with_capacity(cmp::min(len.0 as usize, MAX_BUF_SIZE / core::mem::size_of::<$ty>()));
792                                 for _ in 0..len.0 {
793                                         if let Some(val) = MaybeReadable::read(r)? {
794                                                 ret.push(val);
795                                         }
796                                 }
797                                 Ok(ret)
798                         }
799                 }
800         }
801 }
802 macro_rules! impl_for_vec {
803         ($ty: ty $(, $name: ident)*) => {
804                 impl_writeable_for_vec!($ty $(, $name)*);
805                 impl_readable_for_vec!($ty $(, $name)*);
806         }
807 }
808
809 impl Writeable for Vec<u8> {
810         #[inline]
811         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
812                 CollectionLength(self.len() as u64).write(w)?;
813                 w.write_all(&self)
814         }
815 }
816
817 impl Readable for Vec<u8> {
818         #[inline]
819         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
820                 let mut len: CollectionLength = Readable::read(r)?;
821                 let mut ret = Vec::new();
822                 while len.0 > 0 {
823                         let readamt = cmp::min(len.0 as usize, MAX_BUF_SIZE);
824                         let readstart = ret.len();
825                         ret.resize(readstart + readamt, 0);
826                         r.read_exact(&mut ret[readstart..])?;
827                         len.0 -= readamt as u64;
828                 }
829                 Ok(ret)
830         }
831 }
832
833 impl_for_vec!(ecdsa::Signature);
834 impl_for_vec!(crate::ln::channelmanager::MonitorUpdateCompletionAction);
835 impl_for_vec!((A, B), A, B);
836 impl_writeable_for_vec!(&crate::routing::router::BlindedTail);
837 impl_readable_for_vec!(crate::routing::router::BlindedTail);
838
839 impl Writeable for Vec<Witness> {
840         #[inline]
841         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
842                 (self.len() as u16).write(w)?;
843                 for witness in self {
844                         (witness.serialized_len() as u16).write(w)?;
845                         witness.write(w)?;
846                 }
847                 Ok(())
848         }
849 }
850
851 impl Readable for Vec<Witness> {
852         #[inline]
853         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
854                 let num_witnesses = <u16 as Readable>::read(r)? as usize;
855                 let mut witnesses = Vec::with_capacity(num_witnesses);
856                 for _ in 0..num_witnesses {
857                         // Even though the length of each witness can be inferred in its consensus-encoded form,
858                         // the spec includes a length prefix so that implementations don't have to deserialize
859                         //  each initially. We do that here anyway as in general we'll need to be able to make
860                         // assertions on some properties of the witnesses when receiving a message providing a list
861                         // of witnesses. We'll just do a sanity check for the lengths and error if there is a mismatch.
862                         let witness_len = <u16 as Readable>::read(r)? as usize;
863                         let witness = <Witness as Readable>::read(r)?;
864                         if witness.serialized_len() != witness_len {
865                                 return Err(DecodeError::BadLengthDescriptor);
866                         }
867                         witnesses.push(witness);
868                 }
869                 Ok(witnesses)
870         }
871 }
872
873 impl Writeable for Script {
874         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
875                 (self.len() as u16).write(w)?;
876                 w.write_all(self.as_bytes())
877         }
878 }
879
880 impl Readable for Script {
881         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
882                 let len = <u16 as Readable>::read(r)? as usize;
883                 let mut buf = vec![0; len];
884                 r.read_exact(&mut buf)?;
885                 Ok(Script::from(buf))
886         }
887 }
888
889 impl Writeable for PublicKey {
890         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
891                 self.serialize().write(w)
892         }
893         #[inline]
894         fn serialized_length(&self) -> usize {
895                 PUBLIC_KEY_SIZE
896         }
897 }
898
899 impl Readable for PublicKey {
900         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
901                 let buf: [u8; PUBLIC_KEY_SIZE] = Readable::read(r)?;
902                 match PublicKey::from_slice(&buf) {
903                         Ok(key) => Ok(key),
904                         Err(_) => return Err(DecodeError::InvalidValue),
905                 }
906         }
907 }
908
909 impl Writeable for SecretKey {
910         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
911                 let mut ser = [0; SECRET_KEY_SIZE];
912                 ser.copy_from_slice(&self[..]);
913                 ser.write(w)
914         }
915         #[inline]
916         fn serialized_length(&self) -> usize {
917                 SECRET_KEY_SIZE
918         }
919 }
920
921 impl Readable for SecretKey {
922         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
923                 let buf: [u8; SECRET_KEY_SIZE] = Readable::read(r)?;
924                 match SecretKey::from_slice(&buf) {
925                         Ok(key) => Ok(key),
926                         Err(_) => return Err(DecodeError::InvalidValue),
927                 }
928         }
929 }
930
931 #[cfg(taproot)]
932 impl Writeable for musig2::types::PublicNonce {
933         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
934                 self.serialize().write(w)
935         }
936 }
937
938 #[cfg(taproot)]
939 impl Readable for musig2::types::PublicNonce {
940         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
941                 let buf: [u8; PUBLIC_KEY_SIZE * 2] = Readable::read(r)?;
942                 musig2::types::PublicNonce::from_slice(&buf).map_err(|_| DecodeError::InvalidValue)
943         }
944 }
945
946 #[cfg(taproot)]
947 impl Writeable for PartialSignatureWithNonce {
948         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
949                 self.0.serialize().write(w)?;
950                 self.1.write(w)
951         }
952 }
953
954 #[cfg(taproot)]
955 impl Readable for PartialSignatureWithNonce {
956         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
957                 let partial_signature_buf: [u8; SECRET_KEY_SIZE] = Readable::read(r)?;
958                 let partial_signature = musig2::types::PartialSignature::from_slice(&partial_signature_buf).map_err(|_| DecodeError::InvalidValue)?;
959                 let public_nonce: musig2::types::PublicNonce = Readable::read(r)?;
960                 Ok(PartialSignatureWithNonce(partial_signature, public_nonce))
961         }
962 }
963
964 impl Writeable for Sha256dHash {
965         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
966                 w.write_all(&self[..])
967         }
968 }
969
970 impl Readable for Sha256dHash {
971         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
972                 use bitcoin::hashes::Hash;
973
974                 let buf: [u8; 32] = Readable::read(r)?;
975                 Ok(Sha256dHash::from_slice(&buf[..]).unwrap())
976         }
977 }
978
979 impl Writeable for ecdsa::Signature {
980         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
981                 self.serialize_compact().write(w)
982         }
983 }
984
985 impl Readable for ecdsa::Signature {
986         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
987                 let buf: [u8; COMPACT_SIGNATURE_SIZE] = Readable::read(r)?;
988                 match ecdsa::Signature::from_compact(&buf) {
989                         Ok(sig) => Ok(sig),
990                         Err(_) => return Err(DecodeError::InvalidValue),
991                 }
992         }
993 }
994
995 impl Writeable for schnorr::Signature {
996         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
997                 self.as_ref().write(w)
998         }
999 }
1000
1001 impl Readable for schnorr::Signature {
1002         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1003                 let buf: [u8; SCHNORR_SIGNATURE_SIZE] = Readable::read(r)?;
1004                 match schnorr::Signature::from_slice(&buf) {
1005                         Ok(sig) => Ok(sig),
1006                         Err(_) => return Err(DecodeError::InvalidValue),
1007                 }
1008         }
1009 }
1010
1011 impl Writeable for PaymentPreimage {
1012         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1013                 self.0.write(w)
1014         }
1015 }
1016
1017 impl Readable for PaymentPreimage {
1018         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1019                 let buf: [u8; 32] = Readable::read(r)?;
1020                 Ok(PaymentPreimage(buf))
1021         }
1022 }
1023
1024 impl Writeable for PaymentHash {
1025         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1026                 self.0.write(w)
1027         }
1028 }
1029
1030 impl Readable for PaymentHash {
1031         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1032                 let buf: [u8; 32] = Readable::read(r)?;
1033                 Ok(PaymentHash(buf))
1034         }
1035 }
1036
1037 impl Writeable for PaymentSecret {
1038         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1039                 self.0.write(w)
1040         }
1041 }
1042
1043 impl Readable for PaymentSecret {
1044         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1045                 let buf: [u8; 32] = Readable::read(r)?;
1046                 Ok(PaymentSecret(buf))
1047         }
1048 }
1049
1050 impl<T: Writeable> Writeable for Box<T> {
1051         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1052                 T::write(&**self, w)
1053         }
1054 }
1055
1056 impl<T: Readable> Readable for Box<T> {
1057         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1058                 Ok(Box::new(Readable::read(r)?))
1059         }
1060 }
1061
1062 impl<T: Writeable> Writeable for Option<T> {
1063         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1064                 match *self {
1065                         None => 0u8.write(w)?,
1066                         Some(ref data) => {
1067                                 BigSize(data.serialized_length() as u64 + 1).write(w)?;
1068                                 data.write(w)?;
1069                         }
1070                 }
1071                 Ok(())
1072         }
1073 }
1074
1075 impl<T: Readable> Readable for Option<T>
1076 {
1077         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1078                 let len: BigSize = Readable::read(r)?;
1079                 match len.0 {
1080                         0 => Ok(None),
1081                         len => {
1082                                 let mut reader = FixedLengthReader::new(r, len - 1);
1083                                 Ok(Some(Readable::read(&mut reader)?))
1084                         }
1085                 }
1086         }
1087 }
1088
1089 impl Writeable for Txid {
1090         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1091                 w.write_all(&self[..])
1092         }
1093 }
1094
1095 impl Readable for Txid {
1096         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1097                 use bitcoin::hashes::Hash;
1098
1099                 let buf: [u8; 32] = Readable::read(r)?;
1100                 Ok(Txid::from_slice(&buf[..]).unwrap())
1101         }
1102 }
1103
1104 impl Writeable for BlockHash {
1105         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1106                 w.write_all(&self[..])
1107         }
1108 }
1109
1110 impl Readable for BlockHash {
1111         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1112                 use bitcoin::hashes::Hash;
1113
1114                 let buf: [u8; 32] = Readable::read(r)?;
1115                 Ok(BlockHash::from_slice(&buf[..]).unwrap())
1116         }
1117 }
1118
1119 impl Writeable for ChainHash {
1120         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1121                 w.write_all(self.as_bytes())
1122         }
1123 }
1124
1125 impl Readable for ChainHash {
1126         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1127                 let buf: [u8; 32] = Readable::read(r)?;
1128                 Ok(ChainHash::from(&buf[..]))
1129         }
1130 }
1131
1132 impl Writeable for OutPoint {
1133         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1134                 self.txid.write(w)?;
1135                 self.vout.write(w)?;
1136                 Ok(())
1137         }
1138 }
1139
1140 impl Readable for OutPoint {
1141         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1142                 let txid = Readable::read(r)?;
1143                 let vout = Readable::read(r)?;
1144                 Ok(OutPoint {
1145                         txid,
1146                         vout,
1147                 })
1148         }
1149 }
1150
1151 macro_rules! impl_consensus_ser {
1152         ($bitcoin_type: ty) => {
1153                 impl Writeable for $bitcoin_type {
1154                         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1155                                 match self.consensus_encode(&mut WriterWriteAdaptor(writer)) {
1156                                         Ok(_) => Ok(()),
1157                                         Err(e) => Err(e),
1158                                 }
1159                         }
1160                 }
1161
1162                 impl Readable for $bitcoin_type {
1163                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1164                                 match consensus::encode::Decodable::consensus_decode(r) {
1165                                         Ok(t) => Ok(t),
1166                                         Err(consensus::encode::Error::Io(ref e)) if e.kind() == io::ErrorKind::UnexpectedEof => Err(DecodeError::ShortRead),
1167                                         Err(consensus::encode::Error::Io(e)) => Err(DecodeError::Io(e.kind())),
1168                                         Err(_) => Err(DecodeError::InvalidValue),
1169                                 }
1170                         }
1171                 }
1172         }
1173 }
1174 impl_consensus_ser!(Transaction);
1175 impl_consensus_ser!(TxOut);
1176 impl_consensus_ser!(Witness);
1177
1178 impl<T: Readable> Readable for Mutex<T> {
1179         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1180                 let t: T = Readable::read(r)?;
1181                 Ok(Mutex::new(t))
1182         }
1183 }
1184 impl<T: Writeable> Writeable for Mutex<T> {
1185         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1186                 self.lock().unwrap().write(w)
1187         }
1188 }
1189
1190 impl<A: Readable, B: Readable> Readable for (A, B) {
1191         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1192                 let a: A = Readable::read(r)?;
1193                 let b: B = Readable::read(r)?;
1194                 Ok((a, b))
1195         }
1196 }
1197 impl<A: Writeable, B: Writeable> Writeable for (A, B) {
1198         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1199                 self.0.write(w)?;
1200                 self.1.write(w)
1201         }
1202 }
1203
1204 impl<A: Readable, B: Readable, C: Readable> Readable for (A, B, C) {
1205         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1206                 let a: A = Readable::read(r)?;
1207                 let b: B = Readable::read(r)?;
1208                 let c: C = Readable::read(r)?;
1209                 Ok((a, b, c))
1210         }
1211 }
1212 impl<A: Writeable, B: Writeable, C: Writeable> Writeable for (A, B, C) {
1213         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1214                 self.0.write(w)?;
1215                 self.1.write(w)?;
1216                 self.2.write(w)
1217         }
1218 }
1219
1220 impl<A: Readable, B: Readable, C: Readable, D: Readable> Readable for (A, B, C, D) {
1221         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1222                 let a: A = Readable::read(r)?;
1223                 let b: B = Readable::read(r)?;
1224                 let c: C = Readable::read(r)?;
1225                 let d: D = Readable::read(r)?;
1226                 Ok((a, b, c, d))
1227         }
1228 }
1229 impl<A: Writeable, B: Writeable, C: Writeable, D: Writeable> Writeable for (A, B, C, D) {
1230         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1231                 self.0.write(w)?;
1232                 self.1.write(w)?;
1233                 self.2.write(w)?;
1234                 self.3.write(w)
1235         }
1236 }
1237
1238 impl Writeable for () {
1239         fn write<W: Writer>(&self, _: &mut W) -> Result<(), io::Error> {
1240                 Ok(())
1241         }
1242 }
1243 impl Readable for () {
1244         fn read<R: Read>(_r: &mut R) -> Result<Self, DecodeError> {
1245                 Ok(())
1246         }
1247 }
1248
1249 impl Writeable for String {
1250         #[inline]
1251         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1252                 CollectionLength(self.len() as u64).write(w)?;
1253                 w.write_all(self.as_bytes())
1254         }
1255 }
1256 impl Readable for String {
1257         #[inline]
1258         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1259                 let v: Vec<u8> = Readable::read(r)?;
1260                 let ret = String::from_utf8(v).map_err(|_| DecodeError::InvalidValue)?;
1261                 Ok(ret)
1262         }
1263 }
1264
1265 /// Represents a hostname for serialization purposes.
1266 /// Only the character set and length will be validated.
1267 /// The character set consists of ASCII alphanumeric characters, hyphens, and periods.
1268 /// Its length is guaranteed to be representable by a single byte.
1269 /// This serialization is used by [`BOLT 7`] hostnames.
1270 ///
1271 /// [`BOLT 7`]: https://github.com/lightning/bolts/blob/master/07-routing-gossip.md
1272 #[derive(Clone, Debug, PartialEq, Eq)]
1273 pub struct Hostname(String);
1274 impl Hostname {
1275         /// Returns the length of the hostname.
1276         pub fn len(&self) -> u8 {
1277                 (&self.0).len() as u8
1278         }
1279 }
1280 impl Deref for Hostname {
1281         type Target = String;
1282
1283         fn deref(&self) -> &Self::Target {
1284                 &self.0
1285         }
1286 }
1287 impl From<Hostname> for String {
1288         fn from(hostname: Hostname) -> Self {
1289                 hostname.0
1290         }
1291 }
1292 impl TryFrom<Vec<u8>> for Hostname {
1293         type Error = ();
1294
1295         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
1296                 if let Ok(s) = String::from_utf8(bytes) {
1297                         Hostname::try_from(s)
1298                 } else {
1299                         Err(())
1300                 }
1301         }
1302 }
1303 impl TryFrom<String> for Hostname {
1304         type Error = ();
1305
1306         fn try_from(s: String) -> Result<Self, Self::Error> {
1307                 if s.len() <= 255 && s.chars().all(|c|
1308                         c.is_ascii_alphanumeric() ||
1309                         c == '.' ||
1310                         c == '-'
1311                 ) {
1312                         Ok(Hostname(s))
1313                 } else {
1314                         Err(())
1315                 }
1316         }
1317 }
1318 impl Writeable for Hostname {
1319         #[inline]
1320         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1321                 self.len().write(w)?;
1322                 w.write_all(self.as_bytes())
1323         }
1324 }
1325 impl Readable for Hostname {
1326         #[inline]
1327         fn read<R: Read>(r: &mut R) -> Result<Hostname, DecodeError> {
1328                 let len: u8 = Readable::read(r)?;
1329                 let mut vec = Vec::with_capacity(len.into());
1330                 vec.resize(len.into(), 0);
1331                 r.read_exact(&mut vec)?;
1332                 Hostname::try_from(vec).map_err(|_| DecodeError::InvalidValue)
1333         }
1334 }
1335
1336 impl Writeable for Duration {
1337         #[inline]
1338         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1339                 self.as_secs().write(w)?;
1340                 self.subsec_nanos().write(w)
1341         }
1342 }
1343 impl Readable for Duration {
1344         #[inline]
1345         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1346                 let secs = Readable::read(r)?;
1347                 let nanos = Readable::read(r)?;
1348                 Ok(Duration::new(secs, nanos))
1349         }
1350 }
1351
1352 /// A wrapper for a `Transaction` which can only be constructed with [`TransactionU16LenLimited::new`]
1353 /// if the `Transaction`'s consensus-serialized length is <= u16::MAX.
1354 ///
1355 /// Use [`TransactionU16LenLimited::into_transaction`] to convert into the contained `Transaction`.
1356 #[derive(Clone, Debug, PartialEq, Eq)]
1357 pub struct TransactionU16LenLimited(Transaction);
1358
1359 impl TransactionU16LenLimited {
1360         /// Constructs a new `TransactionU16LenLimited` from a `Transaction` only if it's consensus-
1361         /// serialized length is <= u16::MAX.
1362         pub fn new(transaction: Transaction) -> Result<Self, ()> {
1363                 if transaction.serialized_length() > (u16::MAX as usize) {
1364                         Err(())
1365                 } else {
1366                         Ok(Self(transaction))
1367                 }
1368         }
1369
1370         /// Consumes this `TransactionU16LenLimited` and returns its contained `Transaction`.
1371         pub fn into_transaction(self) -> Transaction {
1372                 self.0
1373         }
1374 }
1375
1376 impl Writeable for TransactionU16LenLimited {
1377         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1378                 (self.0.serialized_length() as u16).write(w)?;
1379                 self.0.write(w)
1380         }
1381 }
1382
1383 impl Readable for TransactionU16LenLimited {
1384         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1385                 let len = <u16 as Readable>::read(r)?;
1386                 let mut tx_reader = FixedLengthReader::new(r, len as u64);
1387                 let tx: Transaction = Readable::read(&mut tx_reader)?;
1388                 if tx_reader.bytes_remain() {
1389                         Err(DecodeError::BadLengthDescriptor)
1390                 } else {
1391                         Ok(Self(tx))
1392                 }
1393         }
1394 }
1395
1396 #[cfg(test)]
1397 mod tests {
1398         use core::convert::TryFrom;
1399         use bitcoin::secp256k1::ecdsa;
1400         use crate::util::ser::{Readable, Hostname, Writeable};
1401
1402         #[test]
1403         fn hostname_conversion() {
1404                 assert_eq!(Hostname::try_from(String::from("a-test.com")).unwrap().as_str(), "a-test.com");
1405
1406                 assert!(Hostname::try_from(String::from("\"")).is_err());
1407                 assert!(Hostname::try_from(String::from("$")).is_err());
1408                 assert!(Hostname::try_from(String::from("⚡")).is_err());
1409                 let mut large_vec = Vec::with_capacity(256);
1410                 large_vec.resize(256, b'A');
1411                 assert!(Hostname::try_from(String::from_utf8(large_vec).unwrap()).is_err());
1412         }
1413
1414         #[test]
1415         fn hostname_serialization() {
1416                 let hostname = Hostname::try_from(String::from("test")).unwrap();
1417                 let mut buf: Vec<u8> = Vec::new();
1418                 hostname.write(&mut buf).unwrap();
1419                 assert_eq!(Hostname::read(&mut buf.as_slice()).unwrap().as_str(), "test");
1420         }
1421
1422         #[test]
1423         /// Taproot will likely fill legacy signature fields with all 0s.
1424         /// This test ensures that doing so won't break serialization.
1425         fn null_signature_codec() {
1426                 let buffer = vec![0u8; 64];
1427                 let mut cursor = crate::io::Cursor::new(buffer.clone());
1428                 let signature = ecdsa::Signature::read(&mut cursor).unwrap();
1429                 let serialization = signature.serialize_compact();
1430                 assert_eq!(buffer, serialization.to_vec())
1431         }
1432
1433         #[test]
1434         fn bigsize_encoding_decoding() {
1435                 let values = vec![0, 252, 253, 65535, 65536, 4294967295, 4294967296, 18446744073709551615];
1436                 let bytes = vec![
1437                         "00",
1438                         "fc",
1439                         "fd00fd",
1440                         "fdffff",
1441                         "fe00010000",
1442                         "feffffffff",
1443                         "ff0000000100000000",
1444                         "ffffffffffffffffff"
1445                 ];
1446                 for i in 0..=7 {
1447                         let mut stream = crate::io::Cursor::new(::hex::decode(bytes[i]).unwrap());
1448                         assert_eq!(super::BigSize::read(&mut stream).unwrap().0, values[i]);
1449                         let mut stream = super::VecWriter(Vec::new());
1450                         super::BigSize(values[i]).write(&mut stream).unwrap();
1451                         assert_eq!(stream.0, ::hex::decode(bytes[i]).unwrap());
1452                 }
1453                 let err_bytes = vec![
1454                         "fd00fc",
1455                         "fe0000ffff",
1456                         "ff00000000ffffffff",
1457                         "fd00",
1458                         "feffff",
1459                         "ffffffffff",
1460                         "fd",
1461                         "fe",
1462                         "ff",
1463                         ""
1464                 ];
1465                 for i in 0..=9 {
1466                         let mut stream = crate::io::Cursor::new(::hex::decode(err_bytes[i]).unwrap());
1467                         if i < 3 {
1468                                 assert_eq!(super::BigSize::read(&mut stream).err(), Some(crate::ln::msgs::DecodeError::InvalidValue));
1469                         } else {
1470                                 assert_eq!(super::BigSize::read(&mut stream).err(), Some(crate::ln::msgs::DecodeError::ShortRead));
1471                         }
1472                 }
1473         }
1474 }