https://github.com/tkaitchuck/aHash/pull/196 bumped the MSRV of
`ahash` in a patch release, which makes it rather difficult for us
to have it as a dependency.
Further, it seems that `ahash` hasn't been particularly robust in
the past, notably
https://github.com/tkaitchuck/aHash/issues/163 and
https://github.com/tkaitchuck/aHash/issues/166.
Luckily, `core` provides `SipHasher` even on no-std (sadly its
SipHash-2-4 unlike the SipHash-1-3 used by the `DefaultHasher` in
`std`). Thus, we drop the `ahash` dependency entirely here and
simply wrap `SipHasher` for our `no-std` HashMaps.
While this isn't expected to materially improve performance, it
does get us ahash 0.8, which allows us to reduce fuzzing
randomness, making our fuzzers much happier.
Sadly, by default `ahash` no longer tries to autodetect a
randomness source, so we cannot simply rely on `hashbrown` to do
randomization for us, but rather have to also explicitly depend on
`ahash`.
hashbrown by default uses ahash, which may be a bit faster, but
more importantly, if we upgrade to hashbrown 0.13/ahash 0.8 we can
make it use a constant randomization factor, making fuzzers happier.
Dunno why they changed it, but the old "depend directly on git"
thing that cargo-fuzz used forever is now deprecated that that
repo is archived, they've now moved to another repo and publish
properly on crates.io.
This resolves a spec-compliance bug with BOLT 4 where we simply
failed to deserialize the message and thus could never return an
HTLC failure message. However, note that BOLT 4 incorrectly hints
that a non-malformed message should be used ("...MUST report a
route failure to the origin node") which we cannot do as we cannot
derive a SharedSecret to encrypt a regular update_fail_htlc message
Summary:
Implementing these, taking inspiration from the surrounding code since i'm a rust n00b.
Test Plan:
```
cargo build
cargo test channel_reestablish
```
output:
```
running 3 tests
test ln::msgs::tests::encoding_channel_reestablish_with_secret ... ok
test ln::msgs::tests::decode_channel_reestablish_bad_length ... ok
test ln::msgs::tests::encoding_channel_reestablish_no_secret ... ok
test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 14 filtered out
```
