This de-duplicates and (hopefully) simplifies a few if-else blocks. The
others were given an exception because I thought they were more readable
as is. I've verified that these changes don't result in larger binaries.
This allows us to use:
(1.26)
- impl Trait
- autoderef in pattern matching
- fixed slice patterns
- inclusive ranges
(1.27)
- dyn Trait
- #[must_use] on functions
To prepare for edition change, dyn is added where applicable. Other
edition changes would require bumping the requirement even higher,
and so they are not applied for now.
- Add tests for the following
- ICMP error responses are not sent in response to broadcast requests
- ARP requests are responded to and inserted into the cache
- ARP requests for someone else are not responded to, but the sender
is still inserted in the cache
The use of this type has several drawbacks:
* It does not allow distinguishing between different error
conditions. In fact, we wrongly conflated some of them
before this commit.
* It does not allow propagation via ? and requires manual use
of map_err, which is especially tiresome for downstream code.
* It prevents us from expanding the set of error conditions
even if right now we have only one.
* It prevents us from blanket using Result<T> everywhere
(a nitpick at most).
Instead, use Result<T, Error> everywhere, and differentiate error
conditions where applicable.
This is a form of an uninitialized read bug; although safe it caused
panics. In short, transmit buffers received from the network stack
should be considered uninitialized (in practice they will often
contain previously transmitted packets or parts thereof). Wrapping
them with the only method we had (e.g. Ipv4Packet) treated the buffer
as if it contained a valid incoming packet, which can easily fail
with Error::Truncated.
This commit splits every `fn new(buffer: T) -> Result<Self, Error>`
method on a `Packet` into three smaller ones:
* `fn check_len(&self) -> Result<(), Error>`, purely a validator;
* `fn new(T) -> Self`, purely a wrapper;
* `fn new_checked(T) -> Result<Self, Error>`, a validating wrapper.
This makes it easy to process ingress packets (using `new_checked`),
egress packets (using `new`), and, if needed, maintain the invariants
at any point during packet construction (using `check_len`).
Fixes#17.
Thibaut Vandervelden
Dario Nieuwenhuis
Alex Crawford
Niclas Hoyer
whitequark
Andrew Cann
whitequark
Dan Robertson