We'll use this to router relay messages on a circuit to the
appropriate stream, and hand them to that stream, without parsing
the message until the stream has been determined.
We now manipulate raw relay cell bodies as (an alias for)
`Box<[u8;509]>` rather than as (an alias for) `[u8;509]`. This
enables us to do much less copying. It will become more important
soon, as we defer parsing relay cell bodies even longer.
Related to #7.
We also use SliceWriter to avoid allocating a Vec<> for every relay
message we want to encode, and instead encode directly into the
cell.
Because the API assumes that many writes are infallible, this writer
takes ownership of the backing object, and will only return it to
you if you didn't run over the end.
I'm going to use this to save some allocations in relay cell bodies
There will be two call sites to demonstrate it.
Eventually maybe this will want to be in tor-basic-utils, since it
doesn't depend on any of the tor-netdoc types. But it would be
sensible to wait until the situation with PeekableIterator and
Itertools is improved.
For now we make this #[doc(hidden)] to avoid it becoming part of our
stable API.
This one was generated (by dgoulet) using `ClientDescEncKey`
encryption. Its information is:
```
Address: paozpdhgz2okvc6kgbxvh2bnfsmt4xergrtcl4obkhopyvwxkpjzvoad.onion
Time period: 19397
Client:
paozpdhgz2okvc6kgbxvh2bnfsmt4xergrtcl4obkhopyvwxkpjzvoad:descriptor:x25519:SDZNMD4RP4SCH4EYTTUZPFRZINNFWAOPPKZ6BINZAC7LREV24RBQ
Service:
descriptor:x25519:SACGOAEODFGCYY22NYZV45ZESFPFLDGLMBWFACKEO34XGHASSAMQ
```
Fixes an instance of #768.
The problem with the test vectors is that I used a random time
period number (1234) and the default-in-tor period length (1440)
without checking whether 1440 _meant_ minutes or seconds. I'll add
another test to Tor to make sure that the time period matches now.
With this change, I can test Tor-generated hsdescs with encryption,
so I'm fairly confident that the new behavior is correct.
Unlike C tor, we treat unrecognized commands as reason to kill off
the connection entirely. That's fine; if we need to add an
unrecognized command in the future, we can use VERSIONS to negotiate
it.
Also, if someday we want this code to support relay channels as
well, we can use some type trickery to have that work too.
Actually, to avoid making a breaking change, I'm deprecating
BadMessage and creating a new InvalidMessage variant that takes a
Cow. This way I don't need to track every crate that re-exposes
tor_bytes::Error and call this a breaking change in those.
Making this change will allow tor_bytes errors to be much more
helpful.
Every FooMsg type now implements Into<AnyFooMsg>, and
TryFrom<FooMsg>.
Additionally, it now implements From<X> for every distinct type that
it supports. This last part lets us discard a bunch of code.
Unfortunately, I needed some downright hackish trickery in order to
get these macros to avoid generating `From<AnyFooMsg> for AnyFooMsg`
and conflicting with the blanket implementation.
The trickery to deal with RelayEarly and Relay being the same type
was not necessarily worth it; I will be separating them and removing
said trickery in the next commit.
Nick Mathewson
Ian Jackson
Ian Jackson