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