git.bitcoin.ninja Git - rust-lightning/blob - 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::Script;
  33 use bitcoin::blockdata::transaction::{OutPoint, Transaction, TxOut};
  34 use bitcoin::consensus;
  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
 516 impl Writeable for u8 {
 517         #[inline]
 518         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 519                 writer.write_all(&[*self])
 520         }
 521 }
 522 impl Readable for u8 {
 523         #[inline]
 524         fn read<R: Read>(reader: &mut R) -> Result<u8, DecodeError> {
 525                 let mut buf = [0; 1];
 526                 reader.read_exact(&mut buf)?;
 527                 Ok(buf[0])
 528         }
 529 }
 530
 531 impl Writeable for bool {
 532         #[inline]
 533         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 534                 writer.write_all(&[if *self {1} else {0}])
 535         }
 536 }
 537 impl Readable for bool {
 538         #[inline]
 539         fn read<R: Read>(reader: &mut R) -> Result<bool, DecodeError> {
 540                 let mut buf = [0; 1];
 541                 reader.read_exact(&mut buf)?;
 542                 if buf[0] != 0 && buf[0] != 1 {
 543                         return Err(DecodeError::InvalidValue);
 544                 }
 545                 Ok(buf[0] == 1)
 546         }
 547 }
 548
 549 // u8 arrays
 550 macro_rules! impl_array {
 551         ( $size:expr ) => (
 552                 impl Writeable for [u8; $size]
 553                 {
 554                         #[inline]
 555                         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 556                                 w.write_all(self)
 557                         }
 558                 }
 559
 560                 impl Readable for [u8; $size]
 561                 {
 562                         #[inline]
 563                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 564                                 let mut buf = [0u8; $size];
 565                                 r.read_exact(&mut buf)?;
 566                                 Ok(buf)
 567                         }
 568                 }
 569         );
 570 }
 571
 572 impl_array!(3); // for rgb, ISO 4712 code
 573 impl_array!(4); // for IPv4
 574 impl_array!(12); // for OnionV2
 575 impl_array!(16); // for IPv6
 576 impl_array!(32); // for channel id & hmac
 577 impl_array!(PUBLIC_KEY_SIZE); // for PublicKey
 578 impl_array!(64); // for ecdsa::Signature and schnorr::Signature
 579 impl_array!(66); // for MuSig2 nonces
 580 impl_array!(1300); // for OnionPacket.hop_data
 581
 582 impl Writeable for [u16; 8] {
 583         #[inline]
 584         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 585                 for v in self.iter() {
 586                         w.write_all(&v.to_be_bytes())?
 587                 }
 588                 Ok(())
 589         }
 590 }
 591
 592 impl Readable for [u16; 8] {
 593         #[inline]
 594         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 595                 let mut buf = [0u8; 16];
 596                 r.read_exact(&mut buf)?;
 597                 let mut res = [0u16; 8];
 598                 for (idx, v) in res.iter_mut().enumerate() {
 599                         *v = (buf[idx*2] as u16) << 8 | (buf[idx*2 + 1] as u16)
 600                 }
 601                 Ok(res)
 602         }
 603 }
 604
 605 /// A type for variable-length values within TLV record where the length is encoded as part of the record.
 606 /// Used to prevent encoding the length twice.
 607 ///
 608 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
 609 pub struct WithoutLength<T>(pub T);
 610
 611 impl Writeable for WithoutLength<&String> {
 612         #[inline]
 613         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 614                 w.write_all(self.0.as_bytes())
 615         }
 616 }
 617 impl Readable for WithoutLength<String> {
 618         #[inline]
 619         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 620                 let v: WithoutLength<Vec<u8>> = Readable::read(r)?;
 621                 Ok(Self(String::from_utf8(v.0).map_err(|_| DecodeError::InvalidValue)?))
 622         }
 623 }
 624 impl<'a> From<&'a String> for WithoutLength<&'a String> {
 625         fn from(s: &'a String) -> Self { Self(s) }
 626 }
 627
 628 impl<'a, T: Writeable> Writeable for WithoutLength<&'a Vec<T>> {
 629         #[inline]
 630         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 631                 for ref v in self.0.iter() {
 632                         v.write(writer)?;
 633                 }
 634                 Ok(())
 635         }
 636 }
 637
 638 impl<T: MaybeReadable> Readable for WithoutLength<Vec<T>> {
 639         #[inline]
 640         fn read<R: Read>(mut reader: &mut R) -> Result<Self, DecodeError> {
 641                 let mut values = Vec::new();
 642                 loop {
 643                         let mut track_read = ReadTrackingReader::new(&mut reader);
 644                         match MaybeReadable::read(&mut track_read) {
 645                                 Ok(Some(v)) => { values.push(v); },
 646                                 Ok(None) => { },
 647                                 // If we failed to read any bytes at all, we reached the end of our TLV
 648                                 // stream and have simply exhausted all entries.
 649                                 Err(ref e) if e == &DecodeError::ShortRead && !track_read.have_read => break,
 650                                 Err(e) => return Err(e),
 651                         }
 652                 }
 653                 Ok(Self(values))
 654         }
 655 }
 656 impl<'a, T> From<&'a Vec<T>> for WithoutLength<&'a Vec<T>> {
 657         fn from(v: &'a Vec<T>) -> Self { Self(v) }
 658 }
 659
 660 #[derive(Debug)]
 661 pub(crate) struct Iterable<'a, I: Iterator<Item = &'a T> + Clone, T: 'a>(pub I);
 662
 663 impl<'a, I: Iterator<Item = &'a T> + Clone, T: 'a + Writeable> Writeable for Iterable<'a, I, T> {
 664         #[inline]
 665         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 666                 for ref v in self.0.clone() {
 667                         v.write(writer)?;
 668                 }
 669                 Ok(())
 670         }
 671 }
 672
 673 #[cfg(test)]
 674 impl<'a, I: Iterator<Item = &'a T> + Clone, T: 'a + PartialEq> PartialEq for Iterable<'a, I, T> {
 675         fn eq(&self, other: &Self) -> bool {
 676                 self.0.clone().collect::<Vec<_>>() == other.0.clone().collect::<Vec<_>>()
 677         }
 678 }
 679
 680 macro_rules! impl_for_map {
 681         ($ty: ident, $keybound: ident, $constr: expr) => {
 682                 impl<K, V> Writeable for $ty<K, V>
 683                         where K: Writeable + Eq + $keybound, V: Writeable
 684                 {
 685                         #[inline]
 686                         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 687                                 CollectionLength(self.len() as u64).write(w)?;
 688                                 for (key, value) in self.iter() {
 689                                         key.write(w)?;
 690                                         value.write(w)?;
 691                                 }
 692                                 Ok(())
 693                         }
 694                 }
 695
 696                 impl<K, V> Readable for $ty<K, V>
 697                         where K: Readable + Eq + $keybound, V: MaybeReadable
 698                 {
 699                         #[inline]
 700                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 701                                 let len: CollectionLength = Readable::read(r)?;
 702                                 let mut ret = $constr(len.0 as usize);
 703                                 for _ in 0..len.0 {
 704                                         let k = K::read(r)?;
 705                                         let v_opt = V::read(r)?;
 706                                         if let Some(v) = v_opt {
 707                                                 if ret.insert(k, v).is_some() {
 708                                                         return Err(DecodeError::InvalidValue);
 709                                                 }
 710                                         }
 711                                 }
 712                                 Ok(ret)
 713                         }
 714                 }
 715         }
 716 }
 717
 718 impl_for_map!(BTreeMap, Ord, |_| BTreeMap::new());
 719 impl_for_map!(HashMap, Hash, |len| HashMap::with_capacity(len));
 720
 721 // HashSet
 722 impl<T> Writeable for HashSet<T>
 723 where T: Writeable + Eq + Hash
 724 {
 725         #[inline]
 726         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 727                 CollectionLength(self.len() as u64).write(w)?;
 728                 for item in self.iter() {
 729                         item.write(w)?;
 730                 }
 731                 Ok(())
 732         }
 733 }
 734
 735 impl<T> Readable for HashSet<T>
 736 where T: Readable + Eq + Hash
 737 {
 738         #[inline]
 739         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 740                 let len: CollectionLength = Readable::read(r)?;
 741                 let mut ret = HashSet::with_capacity(cmp::min(len.0 as usize, MAX_BUF_SIZE / core::mem::size_of::<T>()));
 742                 for _ in 0..len.0 {
 743                         if !ret.insert(T::read(r)?) {
 744                                 return Err(DecodeError::InvalidValue)
 745                         }
 746                 }
 747                 Ok(ret)
 748         }
 749 }
 750
 751 // Vectors
 752 macro_rules! impl_writeable_for_vec {
 753         ($ty: ty $(, $name: ident)*) => {
 754                 impl<$($name : Writeable),*> Writeable for Vec<$ty> {
 755                         #[inline]
 756                         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 757                                 CollectionLength(self.len() as u64).write(w)?;
 758                                 for elem in self.iter() {
 759                                         elem.write(w)?;
 760                                 }
 761                                 Ok(())
 762                         }
 763                 }
 764         }
 765 }
 766 macro_rules! impl_readable_for_vec {
 767         ($ty: ty $(, $name: ident)*) => {
 768                 impl<$($name : Readable),*> Readable for Vec<$ty> {
 769                         #[inline]
 770                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 771                                 let len: CollectionLength = Readable::read(r)?;
 772                                 let mut ret = Vec::with_capacity(cmp::min(len.0 as usize, MAX_BUF_SIZE / core::mem::size_of::<$ty>()));
 773                                 for _ in 0..len.0 {
 774                                         if let Some(val) = MaybeReadable::read(r)? {
 775                                                 ret.push(val);
 776                                         }
 777                                 }
 778                                 Ok(ret)
 779                         }
 780                 }
 781         }
 782 }
 783 macro_rules! impl_for_vec {
 784         ($ty: ty $(, $name: ident)*) => {
 785                 impl_writeable_for_vec!($ty $(, $name)*);
 786                 impl_readable_for_vec!($ty $(, $name)*);
 787         }
 788 }
 789
 790 impl Writeable for Vec<u8> {
 791         #[inline]
 792         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 793                 CollectionLength(self.len() as u64).write(w)?;
 794                 w.write_all(&self)
 795         }
 796 }
 797
 798 impl Readable for Vec<u8> {
 799         #[inline]
 800         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 801                 let mut len: CollectionLength = Readable::read(r)?;
 802                 let mut ret = Vec::new();
 803                 while len.0 > 0 {
 804                         let readamt = cmp::min(len.0 as usize, MAX_BUF_SIZE);
 805                         let readstart = ret.len();
 806                         ret.resize(readstart + readamt, 0);
 807                         r.read_exact(&mut ret[readstart..])?;
 808                         len.0 -= readamt as u64;
 809                 }
 810                 Ok(ret)
 811         }
 812 }
 813
 814 impl_for_vec!(ecdsa::Signature);
 815 impl_for_vec!(crate::ln::channelmanager::MonitorUpdateCompletionAction);
 816 impl_for_vec!((A, B), A, B);
 817 impl_writeable_for_vec!(&crate::routing::router::BlindedTail);
 818 impl_readable_for_vec!(crate::routing::router::BlindedTail);
 819
 820 impl Writeable for Script {
 821         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 822                 (self.len() as u16).write(w)?;
 823                 w.write_all(self.as_bytes())
 824         }
 825 }
 826
 827 impl Readable for Script {
 828         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 829                 let len = <u16 as Readable>::read(r)? as usize;
 830                 let mut buf = vec![0; len];
 831                 r.read_exact(&mut buf)?;
 832                 Ok(Script::from(buf))
 833         }
 834 }
 835
 836 impl Writeable for PublicKey {
 837         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 838                 self.serialize().write(w)
 839         }
 840         #[inline]
 841         fn serialized_length(&self) -> usize {
 842                 PUBLIC_KEY_SIZE
 843         }
 844 }
 845
 846 impl Readable for PublicKey {
 847         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 848                 let buf: [u8; PUBLIC_KEY_SIZE] = Readable::read(r)?;
 849                 match PublicKey::from_slice(&buf) {
 850                         Ok(key) => Ok(key),
 851                         Err(_) => return Err(DecodeError::InvalidValue),
 852                 }
 853         }
 854 }
 855
 856 impl Writeable for SecretKey {
 857         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 858                 let mut ser = [0; SECRET_KEY_SIZE];
 859                 ser.copy_from_slice(&self[..]);
 860                 ser.write(w)
 861         }
 862         #[inline]
 863         fn serialized_length(&self) -> usize {
 864                 SECRET_KEY_SIZE
 865         }
 866 }
 867
 868 impl Readable for SecretKey {
 869         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 870                 let buf: [u8; SECRET_KEY_SIZE] = Readable::read(r)?;
 871                 match SecretKey::from_slice(&buf) {
 872                         Ok(key) => Ok(key),
 873                         Err(_) => return Err(DecodeError::InvalidValue),
 874                 }
 875         }
 876 }
 877
 878 #[cfg(taproot)]
 879 impl Writeable for musig2::types::PublicNonce {
 880         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 881                 self.serialize().write(w)
 882         }
 883 }
 884
 885 #[cfg(taproot)]
 886 impl Readable for musig2::types::PublicNonce {
 887         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 888                 let buf: [u8; PUBLIC_KEY_SIZE * 2] = Readable::read(r)?;
 889                 musig2::types::PublicNonce::from_slice(&buf).map_err(|_| DecodeError::InvalidValue)
 890         }
 891 }
 892
 893 #[cfg(taproot)]
 894 impl Writeable for PartialSignatureWithNonce {
 895         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 896                 self.0.serialize().write(w)?;
 897                 self.1.write(w)
 898         }
 899 }
 900
 901 #[cfg(taproot)]
 902 impl Readable for PartialSignatureWithNonce {
 903         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 904                 let partial_signature_buf: [u8; SECRET_KEY_SIZE] = Readable::read(r)?;
 905                 let partial_signature = musig2::types::PartialSignature::from_slice(&partial_signature_buf).map_err(|_| DecodeError::InvalidValue)?;
 906                 let public_nonce: musig2::types::PublicNonce = Readable::read(r)?;
 907                 Ok(PartialSignatureWithNonce(partial_signature, public_nonce))
 908         }
 909 }
 910
 911 impl Writeable for Sha256dHash {
 912         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 913                 w.write_all(&self[..])
 914         }
 915 }
 916
 917 impl Readable for Sha256dHash {
 918         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 919                 use bitcoin::hashes::Hash;
 920
 921                 let buf: [u8; 32] = Readable::read(r)?;
 922                 Ok(Sha256dHash::from_slice(&buf[..]).unwrap())
 923         }
 924 }
 925
 926 impl Writeable for ecdsa::Signature {
 927         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 928                 self.serialize_compact().write(w)
 929         }
 930 }
 931
 932 impl Readable for ecdsa::Signature {
 933         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 934                 let buf: [u8; COMPACT_SIGNATURE_SIZE] = Readable::read(r)?;
 935                 match ecdsa::Signature::from_compact(&buf) {
 936                         Ok(sig) => Ok(sig),
 937                         Err(_) => return Err(DecodeError::InvalidValue),
 938                 }
 939         }
 940 }
 941
 942 impl Writeable for schnorr::Signature {
 943         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 944                 self.as_ref().write(w)
 945         }
 946 }
 947
 948 impl Readable for schnorr::Signature {
 949         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 950                 let buf: [u8; SCHNORR_SIGNATURE_SIZE] = Readable::read(r)?;
 951                 match schnorr::Signature::from_slice(&buf) {
 952                         Ok(sig) => Ok(sig),
 953                         Err(_) => return Err(DecodeError::InvalidValue),
 954                 }
 955         }
 956 }
 957
 958 impl Writeable for PaymentPreimage {
 959         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 960                 self.0.write(w)
 961         }
 962 }
 963
 964 impl Readable for PaymentPreimage {
 965         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 966                 let buf: [u8; 32] = Readable::read(r)?;
 967                 Ok(PaymentPreimage(buf))
 968         }
 969 }
 970
 971 impl Writeable for PaymentHash {
 972         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 973                 self.0.write(w)
 974         }
 975 }
 976
 977 impl Readable for PaymentHash {
 978         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 979                 let buf: [u8; 32] = Readable::read(r)?;
 980                 Ok(PaymentHash(buf))
 981         }
 982 }
 983
 984 impl Writeable for PaymentSecret {
 985         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 986                 self.0.write(w)
 987         }
 988 }
 989
 990 impl Readable for PaymentSecret {
 991         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 992                 let buf: [u8; 32] = Readable::read(r)?;
 993                 Ok(PaymentSecret(buf))
 994         }
 995 }
 996
 997 impl<T: Writeable> Writeable for Box<T> {
 998         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 999                 T::write(&**self, w)
1000         }
1001 }
1002
1003 impl<T: Readable> Readable for Box<T> {
1004         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1005                 Ok(Box::new(Readable::read(r)?))
1006         }
1007 }
1008
1009 impl<T: Writeable> Writeable for Option<T> {
1010         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1011                 match *self {
1012                         None => 0u8.write(w)?,
1013                         Some(ref data) => {
1014                                 BigSize(data.serialized_length() as u64 + 1).write(w)?;
1015                                 data.write(w)?;
1016                         }
1017                 }
1018                 Ok(())
1019         }
1020 }
1021
1022 impl<T: Readable> Readable for Option<T>
1023 {
1024         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1025                 let len: BigSize = Readable::read(r)?;
1026                 match len.0 {
1027                         0 => Ok(None),
1028                         len => {
1029                                 let mut reader = FixedLengthReader::new(r, len - 1);
1030                                 Ok(Some(Readable::read(&mut reader)?))
1031                         }
1032                 }
1033         }
1034 }
1035
1036 impl Writeable for Txid {
1037         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1038                 w.write_all(&self[..])
1039         }
1040 }
1041
1042 impl Readable for Txid {
1043         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1044                 use bitcoin::hashes::Hash;
1045
1046                 let buf: [u8; 32] = Readable::read(r)?;
1047                 Ok(Txid::from_slice(&buf[..]).unwrap())
1048         }
1049 }
1050
1051 impl Writeable for BlockHash {
1052         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1053                 w.write_all(&self[..])
1054         }
1055 }
1056
1057 impl Readable for BlockHash {
1058         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1059                 use bitcoin::hashes::Hash;
1060
1061                 let buf: [u8; 32] = Readable::read(r)?;
1062                 Ok(BlockHash::from_slice(&buf[..]).unwrap())
1063         }
1064 }
1065
1066 impl Writeable for ChainHash {
1067         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1068                 w.write_all(self.as_bytes())
1069         }
1070 }
1071
1072 impl Readable for ChainHash {
1073         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1074                 let buf: [u8; 32] = Readable::read(r)?;
1075                 Ok(ChainHash::from(&buf[..]))
1076         }
1077 }
1078
1079 impl Writeable for OutPoint {
1080         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1081                 self.txid.write(w)?;
1082                 self.vout.write(w)?;
1083                 Ok(())
1084         }
1085 }
1086
1087 impl Readable for OutPoint {
1088         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1089                 let txid = Readable::read(r)?;
1090                 let vout = Readable::read(r)?;
1091                 Ok(OutPoint {
1092                         txid,
1093                         vout,
1094                 })
1095         }
1096 }
1097
1098 macro_rules! impl_consensus_ser {
1099         ($bitcoin_type: ty) => {
1100                 impl Writeable for $bitcoin_type {
1101                         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1102                                 match self.consensus_encode(&mut WriterWriteAdaptor(writer)) {
1103                                         Ok(_) => Ok(()),
1104                                         Err(e) => Err(e),
1105                                 }
1106                         }
1107                 }
1108
1109                 impl Readable for $bitcoin_type {
1110                         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1111                                 match consensus::encode::Decodable::consensus_decode(r) {
1112                                         Ok(t) => Ok(t),
1113                                         Err(consensus::encode::Error::Io(ref e)) if e.kind() == io::ErrorKind::UnexpectedEof => Err(DecodeError::ShortRead),
1114                                         Err(consensus::encode::Error::Io(e)) => Err(DecodeError::Io(e.kind())),
1115                                         Err(_) => Err(DecodeError::InvalidValue),
1116                                 }
1117                         }
1118                 }
1119         }
1120 }
1121 impl_consensus_ser!(Transaction);
1122 impl_consensus_ser!(TxOut);
1123
1124 impl<T: Readable> Readable for Mutex<T> {
1125         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1126                 let t: T = Readable::read(r)?;
1127                 Ok(Mutex::new(t))
1128         }
1129 }
1130 impl<T: Writeable> Writeable for Mutex<T> {
1131         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1132                 self.lock().unwrap().write(w)
1133         }
1134 }
1135
1136 impl<A: Readable, B: Readable> Readable for (A, B) {
1137         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1138                 let a: A = Readable::read(r)?;
1139                 let b: B = Readable::read(r)?;
1140                 Ok((a, b))
1141         }
1142 }
1143 impl<A: Writeable, B: Writeable> Writeable for (A, B) {
1144         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1145                 self.0.write(w)?;
1146                 self.1.write(w)
1147         }
1148 }
1149
1150 impl<A: Readable, B: Readable, C: Readable> Readable for (A, B, C) {
1151         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1152                 let a: A = Readable::read(r)?;
1153                 let b: B = Readable::read(r)?;
1154                 let c: C = Readable::read(r)?;
1155                 Ok((a, b, c))
1156         }
1157 }
1158 impl<A: Writeable, B: Writeable, C: Writeable> Writeable for (A, B, C) {
1159         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1160                 self.0.write(w)?;
1161                 self.1.write(w)?;
1162                 self.2.write(w)
1163         }
1164 }
1165
1166 impl<A: Readable, B: Readable, C: Readable, D: Readable> Readable for (A, B, C, D) {
1167         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1168                 let a: A = Readable::read(r)?;
1169                 let b: B = Readable::read(r)?;
1170                 let c: C = Readable::read(r)?;
1171                 let d: D = Readable::read(r)?;
1172                 Ok((a, b, c, d))
1173         }
1174 }
1175 impl<A: Writeable, B: Writeable, C: Writeable, D: Writeable> Writeable for (A, B, C, D) {
1176         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1177                 self.0.write(w)?;
1178                 self.1.write(w)?;
1179                 self.2.write(w)?;
1180                 self.3.write(w)
1181         }
1182 }
1183
1184 impl Writeable for () {
1185         fn write<W: Writer>(&self, _: &mut W) -> Result<(), io::Error> {
1186                 Ok(())
1187         }
1188 }
1189 impl Readable for () {
1190         fn read<R: Read>(_r: &mut R) -> Result<Self, DecodeError> {
1191                 Ok(())
1192         }
1193 }
1194
1195 impl Writeable for String {
1196         #[inline]
1197         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1198                 CollectionLength(self.len() as u64).write(w)?;
1199                 w.write_all(self.as_bytes())
1200         }
1201 }
1202 impl Readable for String {
1203         #[inline]
1204         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1205                 let v: Vec<u8> = Readable::read(r)?;
1206                 let ret = String::from_utf8(v).map_err(|_| DecodeError::InvalidValue)?;
1207                 Ok(ret)
1208         }
1209 }
1210
1211 /// Represents a hostname for serialization purposes.
1212 /// Only the character set and length will be validated.
1213 /// The character set consists of ASCII alphanumeric characters, hyphens, and periods.
1214 /// Its length is guaranteed to be representable by a single byte.
1215 /// This serialization is used by [`BOLT 7`] hostnames.
1216 ///
1217 /// [`BOLT 7`]: https://github.com/lightning/bolts/blob/master/07-routing-gossip.md
1218 #[derive(Clone, Debug, PartialEq, Eq)]
1219 pub struct Hostname(String);
1220 impl Hostname {
1221         /// Returns the length of the hostname.
1222         pub fn len(&self) -> u8 {
1223                 (&self.0).len() as u8
1224         }
1225 }
1226 impl Deref for Hostname {
1227         type Target = String;
1228
1229         fn deref(&self) -> &Self::Target {
1230                 &self.0
1231         }
1232 }
1233 impl From<Hostname> for String {
1234         fn from(hostname: Hostname) -> Self {
1235                 hostname.0
1236         }
1237 }
1238 impl TryFrom<Vec<u8>> for Hostname {
1239         type Error = ();
1240
1241         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
1242                 if let Ok(s) = String::from_utf8(bytes) {
1243                         Hostname::try_from(s)
1244                 } else {
1245                         Err(())
1246                 }
1247         }
1248 }
1249 impl TryFrom<String> for Hostname {
1250         type Error = ();
1251
1252         fn try_from(s: String) -> Result<Self, Self::Error> {
1253                 if s.len() <= 255 && s.chars().all(|c|
1254                         c.is_ascii_alphanumeric() ||
1255                         c == '.' ||
1256                         c == '-'
1257                 ) {
1258                         Ok(Hostname(s))
1259                 } else {
1260                         Err(())
1261                 }
1262         }
1263 }
1264 impl Writeable for Hostname {
1265         #[inline]
1266         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1267                 self.len().write(w)?;
1268                 w.write_all(self.as_bytes())
1269         }
1270 }
1271 impl Readable for Hostname {
1272         #[inline]
1273         fn read<R: Read>(r: &mut R) -> Result<Hostname, DecodeError> {
1274                 let len: u8 = Readable::read(r)?;
1275                 let mut vec = Vec::with_capacity(len.into());
1276                 vec.resize(len.into(), 0);
1277                 r.read_exact(&mut vec)?;
1278                 Hostname::try_from(vec).map_err(|_| DecodeError::InvalidValue)
1279         }
1280 }
1281
1282 impl Writeable for Duration {
1283         #[inline]
1284         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1285                 self.as_secs().write(w)?;
1286                 self.subsec_nanos().write(w)
1287         }
1288 }
1289 impl Readable for Duration {
1290         #[inline]
1291         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1292                 let secs = Readable::read(r)?;
1293                 let nanos = Readable::read(r)?;
1294                 Ok(Duration::new(secs, nanos))
1295         }
1296 }
1297
1298 #[cfg(test)]
1299 mod tests {
1300         use core::convert::TryFrom;
1301         use bitcoin::secp256k1::ecdsa;
1302         use crate::util::ser::{Readable, Hostname, Writeable};
1303
1304         #[test]
1305         fn hostname_conversion() {
1306                 assert_eq!(Hostname::try_from(String::from("a-test.com")).unwrap().as_str(), "a-test.com");
1307
1308                 assert!(Hostname::try_from(String::from("\"")).is_err());
1309                 assert!(Hostname::try_from(String::from("$")).is_err());
1310                 assert!(Hostname::try_from(String::from("⚡")).is_err());
1311                 let mut large_vec = Vec::with_capacity(256);
1312                 large_vec.resize(256, b'A');
1313                 assert!(Hostname::try_from(String::from_utf8(large_vec).unwrap()).is_err());
1314         }
1315
1316         #[test]
1317         fn hostname_serialization() {
1318                 let hostname = Hostname::try_from(String::from("test")).unwrap();
1319                 let mut buf: Vec<u8> = Vec::new();
1320                 hostname.write(&mut buf).unwrap();
1321                 assert_eq!(Hostname::read(&mut buf.as_slice()).unwrap().as_str(), "test");
1322         }
1323
1324         #[test]
1325         /// Taproot will likely fill legacy signature fields with all 0s.
1326         /// This test ensures that doing so won't break serialization.
1327         fn null_signature_codec() {
1328                 let buffer = vec![0u8; 64];
1329                 let mut cursor = crate::io::Cursor::new(buffer.clone());
1330                 let signature = ecdsa::Signature::read(&mut cursor).unwrap();
1331                 let serialization = signature.serialize_compact();
1332                 assert_eq!(buffer, serialization.to_vec())
1333         }
1334
1335         #[test]
1336         fn bigsize_encoding_decoding() {
1337                 let values = vec![0, 252, 253, 65535, 65536, 4294967295, 4294967296, 18446744073709551615];
1338                 let bytes = vec![
1339                         "00",
1340                         "fc",
1341                         "fd00fd",
1342                         "fdffff",
1343                         "fe00010000",
1344                         "feffffffff",
1345                         "ff0000000100000000",
1346                         "ffffffffffffffffff"
1347                 ];
1348                 for i in 0..=7 {
1349                         let mut stream = crate::io::Cursor::new(::hex::decode(bytes[i]).unwrap());
1350                         assert_eq!(super::BigSize::read(&mut stream).unwrap().0, values[i]);
1351                         let mut stream = super::VecWriter(Vec::new());
1352                         super::BigSize(values[i]).write(&mut stream).unwrap();
1353                         assert_eq!(stream.0, ::hex::decode(bytes[i]).unwrap());
1354                 }
1355                 let err_bytes = vec![
1356                         "fd00fc",
1357                         "fe0000ffff",
1358                         "ff00000000ffffffff",
1359                         "fd00",
1360                         "feffff",
1361                         "ffffffffff",
1362                         "fd",
1363                         "fe",
1364                         "ff",
1365                         ""
1366                 ];
1367                 for i in 0..=9 {
1368                         let mut stream = crate::io::Cursor::new(::hex::decode(err_bytes[i]).unwrap());
1369                         if i < 3 {
1370                                 assert_eq!(super::BigSize::read(&mut stream).err(), Some(crate::ln::msgs::DecodeError::InvalidValue));
1371                         } else {
1372                                 assert_eq!(super::BigSize::read(&mut stream).err(), Some(crate::ln::msgs::DecodeError::ShortRead));
1373                         }
1374                 }
1375         }
1376 }