Merge pull request #2704 from jkczyz/2023-11-channelmanager-docs
[rust-lightning] / lightning / src / util / ser.rs
index 14c25775174b19dc50f4dabe5ecb434ce0ea259b..f88d9f36a72832ef1161c4ff65b48abb9e66a14a 100644 (file)
@@ -17,9 +17,8 @@ use crate::prelude::*;
 use crate::io::{self, Read, Seek, Write};
 use crate::io_extras::{copy, sink};
 use core::hash::Hash;
-use crate::sync::Mutex;
+use crate::sync::{Mutex, RwLock};
 use core::cmp;
-use core::convert::TryFrom;
 use core::ops::Deref;
 
 use alloc::collections::BTreeMap;
@@ -29,18 +28,21 @@ use bitcoin::secp256k1::constants::{PUBLIC_KEY_SIZE, SECRET_KEY_SIZE, COMPACT_SI
 use bitcoin::secp256k1::ecdsa;
 use bitcoin::secp256k1::schnorr;
 use bitcoin::blockdata::constants::ChainHash;
-use bitcoin::blockdata::script::Script;
+use bitcoin::blockdata::script::{self, ScriptBuf};
 use bitcoin::blockdata::transaction::{OutPoint, Transaction, TxOut};
-use bitcoin::consensus;
+use bitcoin::{consensus, Witness};
 use bitcoin::consensus::Encodable;
 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
 use bitcoin::hash_types::{Txid, BlockHash};
-use core::marker::Sized;
 use core::time::Duration;
+use crate::chain::ClaimId;
 use crate::ln::msgs::DecodeError;
+#[cfg(taproot)]
+use crate::ln::msgs::PartialSignatureWithNonce;
 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
 
 use crate::util::byte_utils::{be48_to_array, slice_to_be48};
+use crate::util::string::UntrustedString;
 
 /// serialization buffer size
 pub const MAX_BUF_SIZE: usize = 64 * 1024;
@@ -48,7 +50,7 @@ pub const MAX_BUF_SIZE: usize = 64 * 1024;
 /// A simplified version of [`std::io::Write`] that exists largely for backwards compatibility.
 /// An impl is provided for any type that also impls [`std::io::Write`].
 ///
-/// (C-not exported) as we only export serialization to/from byte arrays instead
+/// This is not exported to bindings users as we only export serialization to/from byte arrays instead
 pub trait Writer {
        /// Writes the given buf out. See std::io::Write::write_all for more
        fn write_all(&mut self, buf: &[u8]) -> Result<(), io::Error>;
@@ -89,6 +91,8 @@ impl Writer for VecWriter {
 
 /// Writer that only tracks the amount of data written - useful if you need to calculate the length
 /// of some data when serialized but don't yet need the full data.
+///
+/// This is not exported to bindings users as manual TLV building is not currently supported in bindings
 pub struct LengthCalculatingWriter(pub usize);
 impl Writer for LengthCalculatingWriter {
        #[inline]
@@ -100,14 +104,16 @@ impl Writer for LengthCalculatingWriter {
 
 /// Essentially [`std::io::Take`] but a bit simpler and with a method to walk the underlying stream
 /// forward to ensure we always consume exactly the fixed length specified.
-pub struct FixedLengthReader<R: Read> {
-       read: R,
+///
+/// This is not exported to bindings users as manual TLV building is not currently supported in bindings
+pub struct FixedLengthReader<'a, R: Read> {
+       read: &'a mut R,
        bytes_read: u64,
        total_bytes: u64,
 }
-impl<R: Read> FixedLengthReader<R> {
+impl<'a, R: Read> FixedLengthReader<'a, R> {
        /// Returns a new [`FixedLengthReader`].
-       pub fn new(read: R, total_bytes: u64) -> Self {
+       pub fn new(read: &'a mut R, total_bytes: u64) -> Self {
                Self { read, bytes_read: 0, total_bytes }
        }
 
@@ -128,7 +134,7 @@ impl<R: Read> FixedLengthReader<R> {
                }
        }
 }
-impl<R: Read> Read for FixedLengthReader<R> {
+impl<'a, R: Read> Read for FixedLengthReader<'a, R> {
        #[inline]
        fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
                if self.total_bytes == self.bytes_read {
@@ -146,7 +152,7 @@ impl<R: Read> Read for FixedLengthReader<R> {
        }
 }
 
-impl<R: Read> LengthRead for FixedLengthReader<R> {
+impl<'a, R: Read> LengthRead for FixedLengthReader<'a, R> {
        #[inline]
        fn total_bytes(&self) -> u64 {
                self.total_bytes
@@ -155,6 +161,8 @@ impl<R: Read> LengthRead for FixedLengthReader<R> {
 
 /// A [`Read`] implementation which tracks whether any bytes have been read at all. This allows us to distinguish
 /// between "EOF reached before we started" and "EOF reached mid-read".
+///
+/// This is not exported to bindings users as manual TLV building is not currently supported in bindings
 pub struct ReadTrackingReader<R: Read> {
        read: R,
        /// Returns whether we have read from this reader or not yet.
@@ -182,15 +190,21 @@ impl<R: Read> Read for ReadTrackingReader<R> {
 
 /// A trait that various LDK types implement allowing them to be written out to a [`Writer`].
 ///
-/// (C-not exported) as we only export serialization to/from byte arrays instead
+/// This is not exported to bindings users as we only export serialization to/from byte arrays instead
 pub trait Writeable {
        /// Writes `self` out to the given [`Writer`].
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error>;
 
        /// Writes `self` out to a `Vec<u8>`.
        fn encode(&self) -> Vec<u8> {
-               let mut msg = VecWriter(Vec::new());
+               let len = self.serialized_length();
+               let mut msg = VecWriter(Vec::with_capacity(len));
                self.write(&mut msg).unwrap();
+               // Note that objects with interior mutability may change size between when we called
+               // serialized_length and when we called write. That's okay, but shouldn't happen during
+               // testing as most of our tests are not threaded.
+               #[cfg(test)]
+               debug_assert_eq!(len, msg.0.len());
                msg.0
        }
 
@@ -201,6 +215,7 @@ pub trait Writeable {
                0u16.write(&mut msg).unwrap();
                self.write(&mut msg).unwrap();
                let len = msg.0.len();
+               debug_assert_eq!(len - 2, self.serialized_length());
                msg.0[..2].copy_from_slice(&(len as u16 - 2).to_be_bytes());
                msg.0
        }
@@ -222,7 +237,7 @@ impl<'a, T: Writeable> Writeable for &'a T {
 
 /// A trait that various LDK types implement allowing them to be read in from a [`Read`].
 ///
-/// (C-not exported) as we only export serialization to/from byte arrays instead
+/// This is not exported to bindings users as we only export serialization to/from byte arrays instead
 pub trait Readable
        where Self: Sized
 {
@@ -240,7 +255,7 @@ pub(crate) trait SeekReadable where Self: Sized {
 /// A trait that various higher-level LDK types implement allowing them to be read in
 /// from a [`Read`] given some additional set of arguments which is required to deserialize.
 ///
-/// (C-not exported) as we only export serialization to/from byte arrays instead
+/// This is not exported to bindings users as we only export serialization to/from byte arrays instead
 pub trait ReadableArgs<P>
        where Self: Sized
 {
@@ -273,7 +288,7 @@ pub(crate) trait LengthReadable where Self: Sized
 
 /// A trait that various LDK types implement allowing them to (maybe) be read in from a [`Read`].
 ///
-/// (C-not exported) as we only export serialization to/from byte arrays instead
+/// This is not exported to bindings users as we only export serialization to/from byte arrays instead
 pub trait MaybeReadable
        where Self: Sized
 {
@@ -289,6 +304,8 @@ impl<T: Readable> MaybeReadable for T {
 }
 
 /// Wrapper to read a required (non-optional) TLV record.
+///
+/// This is not exported to bindings users as manual TLV building is not currently supported in bindings
 pub struct RequiredWrapper<T>(pub Option<T>);
 impl<T: Readable> Readable for RequiredWrapper<T> {
        #[inline]
@@ -311,6 +328,8 @@ impl<T> From<T> for RequiredWrapper<T> {
 
 /// Wrapper to read a required (non-optional) TLV record that may have been upgraded without
 /// backwards compat.
+///
+/// This is not exported to bindings users as manual TLV building is not currently supported in bindings
 pub struct UpgradableRequired<T: MaybeReadable>(pub Option<T>);
 impl<T: MaybeReadable> MaybeReadable for UpgradableRequired<T> {
        #[inline]
@@ -344,19 +363,20 @@ impl Readable for U48 {
 /// encoded in several different ways, which we must check for at deserialization-time. Thus, if
 /// you're looking for an example of a variable-length integer to use for your own project, move
 /// along, this is a rather poor design.
+#[derive(Clone, Copy, Debug, Hash, PartialOrd, Ord, PartialEq, Eq)]
 pub struct BigSize(pub u64);
 impl Writeable for BigSize {
        #[inline]
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                match self.0 {
-                       0...0xFC => {
+                       0..=0xFC => {
                                (self.0 as u8).write(writer)
                        },
-                       0xFD...0xFFFF => {
+                       0xFD..=0xFFFF => {
                                0xFDu8.write(writer)?;
                                (self.0 as u16).write(writer)
                        },
-                       0x10000...0xFFFFFFFF => {
+                       0x10000..=0xFFFFFFFF => {
                                0xFEu8.write(writer)?;
                                (self.0 as u32).write(writer)
                        },
@@ -500,6 +520,10 @@ impl_writeable_primitive!(u128, 16);
 impl_writeable_primitive!(u64, 8);
 impl_writeable_primitive!(u32, 4);
 impl_writeable_primitive!(u16, 2);
+impl_writeable_primitive!(i64, 8);
+impl_writeable_primitive!(i32, 4);
+impl_writeable_primitive!(i16, 2);
+impl_writeable_primitive!(i8, 1);
 
 impl Writeable for u8 {
        #[inline]
@@ -534,63 +558,55 @@ impl Readable for bool {
        }
 }
 
-// u8 arrays
 macro_rules! impl_array {
-       ( $size:expr ) => (
-               impl Writeable for [u8; $size]
-               {
+       ($size:expr, $ty: ty) => (
+               impl Writeable for [$ty; $size] {
                        #[inline]
                        fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
-                               w.write_all(self)
+                               let mut out = [0; $size * core::mem::size_of::<$ty>()];
+                               for (idx, v) in self.iter().enumerate() {
+                                       let startpos = idx * core::mem::size_of::<$ty>();
+                                       out[startpos..startpos + core::mem::size_of::<$ty>()].copy_from_slice(&v.to_be_bytes());
+                               }
+                               w.write_all(&out)
                        }
                }
 
-               impl Readable for [u8; $size]
-               {
+               impl Readable for [$ty; $size] {
                        #[inline]
                        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
-                               let mut buf = [0u8; $size];
+                               let mut buf = [0u8; $size * core::mem::size_of::<$ty>()];
                                r.read_exact(&mut buf)?;
-                               Ok(buf)
+                               let mut res = [0; $size];
+                               for (idx, v) in res.iter_mut().enumerate() {
+                                       let startpos = idx * core::mem::size_of::<$ty>();
+                                       let mut arr = [0; core::mem::size_of::<$ty>()];
+                                       arr.copy_from_slice(&buf[startpos..startpos + core::mem::size_of::<$ty>()]);
+                                       *v = <$ty>::from_be_bytes(arr);
+                               }
+                               Ok(res)
                        }
                }
        );
 }
 
-impl_array!(3); // for rgb, ISO 4712 code
-impl_array!(4); // for IPv4
-impl_array!(12); // for OnionV2
-impl_array!(16); // for IPv6
-impl_array!(32); // for channel id & hmac
-impl_array!(PUBLIC_KEY_SIZE); // for PublicKey
-impl_array!(64); // for ecdsa::Signature and schnorr::Signature
-impl_array!(1300); // for OnionPacket.hop_data
+impl_array!(3, u8); // for rgb, ISO 4712 code
+impl_array!(4, u8); // for IPv4
+impl_array!(12, u8); // for OnionV2
+impl_array!(16, u8); // for IPv6
+impl_array!(32, u8); // for channel id & hmac
+impl_array!(PUBLIC_KEY_SIZE, u8); // for PublicKey
+impl_array!(64, u8); // for ecdsa::Signature and schnorr::Signature
+impl_array!(66, u8); // for MuSig2 nonces
+impl_array!(1300, u8); // for OnionPacket.hop_data
 
-impl Writeable for [u16; 8] {
-       #[inline]
-       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
-               for v in self.iter() {
-                       w.write_all(&v.to_be_bytes())?
-               }
-               Ok(())
-       }
-}
-
-impl Readable for [u16; 8] {
-       #[inline]
-       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
-               let mut buf = [0u8; 16];
-               r.read_exact(&mut buf)?;
-               let mut res = [0u16; 8];
-               for (idx, v) in res.iter_mut().enumerate() {
-                       *v = (buf[idx] as u16) << 8 | (buf[idx + 1] as u16)
-               }
-               Ok(res)
-       }
-}
+impl_array!(8, u16);
+impl_array!(32, u16);
 
 /// A type for variable-length values within TLV record where the length is encoded as part of the record.
 /// Used to prevent encoding the length twice.
+///
+/// This is not exported to bindings users as manual TLV building is not currently supported in bindings
 pub struct WithoutLength<T>(pub T);
 
 impl Writeable for WithoutLength<&String> {
@@ -610,6 +626,21 @@ impl<'a> From<&'a String> for WithoutLength<&'a String> {
        fn from(s: &'a String) -> Self { Self(s) }
 }
 
+
+impl Writeable for WithoutLength<&UntrustedString> {
+       #[inline]
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               WithoutLength(&self.0.0).write(w)
+       }
+}
+impl Readable for WithoutLength<UntrustedString> {
+       #[inline]
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let s: WithoutLength<String> = Readable::read(r)?;
+               Ok(Self(UntrustedString(s.0)))
+       }
+}
+
 impl<'a, T: Writeable> Writeable for WithoutLength<&'a Vec<T>> {
        #[inline]
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
@@ -642,6 +673,21 @@ impl<'a, T> From<&'a Vec<T>> for WithoutLength<&'a Vec<T>> {
        fn from(v: &'a Vec<T>) -> Self { Self(v) }
 }
 
+impl Writeable for WithoutLength<&ScriptBuf> {
+       #[inline]
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+               writer.write_all(self.0.as_bytes())
+       }
+}
+
+impl Readable for WithoutLength<ScriptBuf> {
+       #[inline]
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let v: WithoutLength<Vec<u8>> = Readable::read(r)?;
+               Ok(WithoutLength(script::Builder::from(v.0).into_script()))
+       }
+}
+
 #[derive(Debug)]
 pub(crate) struct Iterable<'a, I: Iterator<Item = &'a T> + Clone, T: 'a>(pub I);
 
@@ -701,7 +747,7 @@ macro_rules! impl_for_map {
 }
 
 impl_for_map!(BTreeMap, Ord, |_| BTreeMap::new());
-impl_for_map!(HashMap, Hash, |len| HashMap::with_capacity(len));
+impl_for_map!(HashMap, Hash, |len| hash_map_with_capacity(len));
 
 // HashSet
 impl<T> Writeable for HashSet<T>
@@ -723,7 +769,7 @@ where T: Readable + Eq + Hash
        #[inline]
        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
                let len: CollectionLength = Readable::read(r)?;
-               let mut ret = HashSet::with_capacity(cmp::min(len.0 as usize, MAX_BUF_SIZE / core::mem::size_of::<T>()));
+               let mut ret = hash_set_with_capacity(cmp::min(len.0 as usize, MAX_BUF_SIZE / core::mem::size_of::<T>()));
                for _ in 0..len.0 {
                        if !ret.insert(T::read(r)?) {
                                return Err(DecodeError::InvalidValue)
@@ -734,7 +780,7 @@ where T: Readable + Eq + Hash
 }
 
 // Vectors
-macro_rules! impl_for_vec {
+macro_rules! impl_writeable_for_vec {
        ($ty: ty $(, $name: ident)*) => {
                impl<$($name : Writeable),*> Writeable for Vec<$ty> {
                        #[inline]
@@ -746,7 +792,10 @@ macro_rules! impl_for_vec {
                                Ok(())
                        }
                }
-
+       }
+}
+macro_rules! impl_readable_for_vec {
+       ($ty: ty $(, $name: ident)*) => {
                impl<$($name : Readable),*> Readable for Vec<$ty> {
                        #[inline]
                        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
@@ -762,6 +811,55 @@ macro_rules! impl_for_vec {
                }
        }
 }
+macro_rules! impl_for_vec {
+       ($ty: ty $(, $name: ident)*) => {
+               impl_writeable_for_vec!($ty $(, $name)*);
+               impl_readable_for_vec!($ty $(, $name)*);
+       }
+}
+
+// Alternatives to impl_writeable_for_vec/impl_readable_for_vec that add a length prefix to each
+// element in the Vec. Intended to be used when elements have variable lengths.
+macro_rules! impl_writeable_for_vec_with_element_length_prefix {
+       ($ty: ty $(, $name: ident)*) => {
+               impl<$($name : Writeable),*> Writeable for Vec<$ty> {
+                       #[inline]
+                       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+                               CollectionLength(self.len() as u64).write(w)?;
+                               for elem in self.iter() {
+                                       CollectionLength(elem.serialized_length() as u64).write(w)?;
+                                       elem.write(w)?;
+                               }
+                               Ok(())
+                       }
+               }
+       }
+}
+macro_rules! impl_readable_for_vec_with_element_length_prefix {
+       ($ty: ty $(, $name: ident)*) => {
+               impl<$($name : Readable),*> Readable for Vec<$ty> {
+                       #[inline]
+                       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+                               let len: CollectionLength = Readable::read(r)?;
+                               let mut ret = Vec::with_capacity(cmp::min(len.0 as usize, MAX_BUF_SIZE / core::mem::size_of::<$ty>()));
+                               for _ in 0..len.0 {
+                                       let elem_len: CollectionLength = Readable::read(r)?;
+                                       let mut elem_reader = FixedLengthReader::new(r, elem_len.0);
+                                       if let Some(val) = MaybeReadable::read(&mut elem_reader)? {
+                                               ret.push(val);
+                                       }
+                               }
+                               Ok(ret)
+                       }
+               }
+       }
+}
+macro_rules! impl_for_vec_with_element_length_prefix {
+       ($ty: ty $(, $name: ident)*) => {
+               impl_writeable_for_vec_with_element_length_prefix!($ty $(, $name)*);
+               impl_readable_for_vec_with_element_length_prefix!($ty $(, $name)*);
+       }
+}
 
 impl Writeable for Vec<u8> {
        #[inline]
@@ -788,22 +886,62 @@ impl Readable for Vec<u8> {
 }
 
 impl_for_vec!(ecdsa::Signature);
+impl_for_vec!(crate::chain::channelmonitor::ChannelMonitorUpdate);
 impl_for_vec!(crate::ln::channelmanager::MonitorUpdateCompletionAction);
+impl_for_vec!(crate::ln::msgs::SocketAddress);
 impl_for_vec!((A, B), A, B);
+impl_writeable_for_vec!(&crate::routing::router::BlindedTail);
+impl_readable_for_vec!(crate::routing::router::BlindedTail);
+impl_for_vec_with_element_length_prefix!(crate::ln::msgs::UpdateAddHTLC);
+impl_writeable_for_vec_with_element_length_prefix!(&crate::ln::msgs::UpdateAddHTLC);
+
+impl Writeable for Vec<Witness> {
+       #[inline]
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               (self.len() as u16).write(w)?;
+               for witness in self {
+                       (witness.serialized_len() as u16).write(w)?;
+                       witness.write(w)?;
+               }
+               Ok(())
+       }
+}
+
+impl Readable for Vec<Witness> {
+       #[inline]
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let num_witnesses = <u16 as Readable>::read(r)? as usize;
+               let mut witnesses = Vec::with_capacity(num_witnesses);
+               for _ in 0..num_witnesses {
+                       // Even though the length of each witness can be inferred in its consensus-encoded form,
+                       // the spec includes a length prefix so that implementations don't have to deserialize
+                       //  each initially. We do that here anyway as in general we'll need to be able to make
+                       // assertions on some properties of the witnesses when receiving a message providing a list
+                       // of witnesses. We'll just do a sanity check for the lengths and error if there is a mismatch.
+                       let witness_len = <u16 as Readable>::read(r)? as usize;
+                       let witness = <Witness as Readable>::read(r)?;
+                       if witness.serialized_len() != witness_len {
+                               return Err(DecodeError::BadLengthDescriptor);
+                       }
+                       witnesses.push(witness);
+               }
+               Ok(witnesses)
+       }
+}
 
-impl Writeable for Script {
+impl Writeable for ScriptBuf {
        fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
                (self.len() as u16).write(w)?;
                w.write_all(self.as_bytes())
        }
 }
 
-impl Readable for Script {
+impl Readable for ScriptBuf {
        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
                let len = <u16 as Readable>::read(r)? as usize;
                let mut buf = vec![0; len];
                r.read_exact(&mut buf)?;
-               Ok(Script::from(buf))
+               Ok(ScriptBuf::from(buf))
        }
 }
 
@@ -849,6 +987,39 @@ impl Readable for SecretKey {
        }
 }
 
+#[cfg(taproot)]
+impl Writeable for musig2::types::PublicNonce {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               self.serialize().write(w)
+       }
+}
+
+#[cfg(taproot)]
+impl Readable for musig2::types::PublicNonce {
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let buf: [u8; PUBLIC_KEY_SIZE * 2] = Readable::read(r)?;
+               musig2::types::PublicNonce::from_slice(&buf).map_err(|_| DecodeError::InvalidValue)
+       }
+}
+
+#[cfg(taproot)]
+impl Writeable for PartialSignatureWithNonce {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               self.0.serialize().write(w)?;
+               self.1.write(w)
+       }
+}
+
+#[cfg(taproot)]
+impl Readable for PartialSignatureWithNonce {
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let partial_signature_buf: [u8; SECRET_KEY_SIZE] = Readable::read(r)?;
+               let partial_signature = musig2::types::PartialSignature::from_slice(&partial_signature_buf).map_err(|_| DecodeError::InvalidValue)?;
+               let public_nonce: musig2::types::PublicNonce = Readable::read(r)?;
+               Ok(PartialSignatureWithNonce(partial_signature, public_nonce))
+       }
+}
+
 impl Writeable for Sha256dHash {
        fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
                w.write_all(&self[..])
@@ -1013,7 +1184,7 @@ impl Writeable for ChainHash {
 impl Readable for ChainHash {
        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
                let buf: [u8; 32] = Readable::read(r)?;
-               Ok(ChainHash::from(&buf[..]))
+               Ok(ChainHash::from(buf))
        }
 }
 
@@ -1061,6 +1232,7 @@ macro_rules! impl_consensus_ser {
 }
 impl_consensus_ser!(Transaction);
 impl_consensus_ser!(TxOut);
+impl_consensus_ser!(Witness);
 
 impl<T: Readable> Readable for Mutex<T> {
        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
@@ -1074,6 +1246,18 @@ impl<T: Writeable> Writeable for Mutex<T> {
        }
 }
 
+impl<T: Readable> Readable for RwLock<T> {
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let t: T = Readable::read(r)?;
+               Ok(RwLock::new(t))
+       }
+}
+impl<T: Writeable> Writeable for RwLock<T> {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               self.read().unwrap().write(w)
+       }
+}
+
 impl<A: Readable, B: Readable> Readable for (A, B) {
        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
                let a: A = Readable::read(r)?;
@@ -1156,7 +1340,7 @@ impl Readable for String {
 /// This serialization is used by [`BOLT 7`] hostnames.
 ///
 /// [`BOLT 7`]: https://github.com/lightning/bolts/blob/master/07-routing-gossip.md
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct Hostname(String);
 impl Hostname {
        /// Returns the length of the hostname.
@@ -1164,6 +1348,13 @@ impl Hostname {
                (&self.0).len() as u8
        }
 }
+
+impl core::fmt::Display for Hostname {
+       fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+               write!(f, "{}", self.0)?;
+               Ok(())
+       }
+}
 impl Deref for Hostname {
        type Target = String;
 
@@ -1220,6 +1411,7 @@ impl Readable for Hostname {
        }
 }
 
+/// This is not exported to bindings users as `Duration`s are simply mapped as ints.
 impl Writeable for Duration {
        #[inline]
        fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
@@ -1227,6 +1419,7 @@ impl Writeable for Duration {
                self.subsec_nanos().write(w)
        }
 }
+/// This is not exported to bindings users as `Duration`s are simply mapped as ints.
 impl Readable for Duration {
        #[inline]
        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
@@ -1236,10 +1429,73 @@ impl Readable for Duration {
        }
 }
 
+/// A wrapper for a `Transaction` which can only be constructed with [`TransactionU16LenLimited::new`]
+/// if the `Transaction`'s consensus-serialized length is <= u16::MAX.
+///
+/// Use [`TransactionU16LenLimited::into_transaction`] to convert into the contained `Transaction`.
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+pub struct TransactionU16LenLimited(Transaction);
+
+impl TransactionU16LenLimited {
+       /// Constructs a new `TransactionU16LenLimited` from a `Transaction` only if it's consensus-
+       /// serialized length is <= u16::MAX.
+       pub fn new(transaction: Transaction) -> Result<Self, ()> {
+               if transaction.serialized_length() > (u16::MAX as usize) {
+                       Err(())
+               } else {
+                       Ok(Self(transaction))
+               }
+       }
+
+       /// Consumes this `TransactionU16LenLimited` and returns its contained `Transaction`.
+       pub fn into_transaction(self) -> Transaction {
+               self.0
+       }
+
+       /// Returns a reference to the contained `Transaction`
+       pub fn as_transaction(&self) -> &Transaction {
+               &self.0
+       }
+}
+
+impl Writeable for TransactionU16LenLimited {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               (self.0.serialized_length() as u16).write(w)?;
+               self.0.write(w)
+       }
+}
+
+impl Readable for TransactionU16LenLimited {
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let len = <u16 as Readable>::read(r)?;
+               let mut tx_reader = FixedLengthReader::new(r, len as u64);
+               let tx: Transaction = Readable::read(&mut tx_reader)?;
+               if tx_reader.bytes_remain() {
+                       Err(DecodeError::BadLengthDescriptor)
+               } else {
+                       Ok(Self(tx))
+               }
+       }
+}
+
+impl Writeable for ClaimId {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+               self.0.write(writer)
+       }
+}
+
+impl Readable for ClaimId {
+       fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+               Ok(Self(Readable::read(reader)?))
+       }
+}
+
 #[cfg(test)]
 mod tests {
-       use core::convert::TryFrom;
+       use bitcoin::hashes::hex::FromHex;
+       use bitcoin::secp256k1::ecdsa;
        use crate::util::ser::{Readable, Hostname, Writeable};
+       use crate::prelude::*;
 
        #[test]
        fn hostname_conversion() {
@@ -1260,4 +1516,57 @@ mod tests {
                hostname.write(&mut buf).unwrap();
                assert_eq!(Hostname::read(&mut buf.as_slice()).unwrap().as_str(), "test");
        }
+
+       #[test]
+       /// Taproot will likely fill legacy signature fields with all 0s.
+       /// This test ensures that doing so won't break serialization.
+       fn null_signature_codec() {
+               let buffer = vec![0u8; 64];
+               let mut cursor = crate::io::Cursor::new(buffer.clone());
+               let signature = ecdsa::Signature::read(&mut cursor).unwrap();
+               let serialization = signature.serialize_compact();
+               assert_eq!(buffer, serialization.to_vec())
+       }
+
+       #[test]
+       fn bigsize_encoding_decoding() {
+               let values = vec![0, 252, 253, 65535, 65536, 4294967295, 4294967296, 18446744073709551615];
+               let bytes = vec![
+                       "00",
+                       "fc",
+                       "fd00fd",
+                       "fdffff",
+                       "fe00010000",
+                       "feffffffff",
+                       "ff0000000100000000",
+                       "ffffffffffffffffff"
+               ];
+               for i in 0..=7 {
+                       let mut stream = crate::io::Cursor::new(<Vec<u8>>::from_hex(bytes[i]).unwrap());
+                       assert_eq!(super::BigSize::read(&mut stream).unwrap().0, values[i]);
+                       let mut stream = super::VecWriter(Vec::new());
+                       super::BigSize(values[i]).write(&mut stream).unwrap();
+                       assert_eq!(stream.0, <Vec<u8>>::from_hex(bytes[i]).unwrap());
+               }
+               let err_bytes = vec![
+                       "fd00fc",
+                       "fe0000ffff",
+                       "ff00000000ffffffff",
+                       "fd00",
+                       "feffff",
+                       "ffffffffff",
+                       "fd",
+                       "fe",
+                       "ff",
+                       ""
+               ];
+               for i in 0..=9 {
+                       let mut stream = crate::io::Cursor::new(<Vec<u8>>::from_hex(err_bytes[i]).unwrap());
+                       if i < 3 {
+                               assert_eq!(super::BigSize::read(&mut stream).err(), Some(crate::ln::msgs::DecodeError::InvalidValue));
+                       } else {
+                               assert_eq!(super::BigSize::read(&mut stream).err(), Some(crate::ln::msgs::DecodeError::ShortRead));
+                       }
+               }
+       }
 }