This commit fixes a small bug, where the TcpSocket computed the maximum
size per payload in a tx_buffer without taking into account the MTU
defined by the underlying network device.
Previously, the window update was sent anytime it changed. This is
not desirable for 2 reasons:
- It would send window updates in TimeWait or Closed states, which is incorrect.
- It would send window updates in states where we've already received the
remote side's FIN, such as CloseWait. This is not necessarily incorrect, but
is useless, since the remote side is not going to send us more data, therefore
it's not interested in our window size anymore.
This allows applications to distinguish whether the remote end has
gracefully closed the connection with a FIN (in which case it has
received all the data intact), or the connection has failed due to e.g. a
RST or a timeout (in which case the received data may be truncated).
Previously, `ack_reply()` was sending the ack number present in `remote_last_ack`,
which is only updated by `dispatch`. This means the ack replies could contain
a wrong, old ack number.
Most of the time this simply caused wasting an extra roundtrip until the socket state
settles down, but in extreme cases it could lead to an infinite loop of packets, such
as in https://github.com/smoltcp-rs/smoltcp/issues/338Fixes#338
`TCPSocket` buffers are type `RingBuffer<'a, _>` whilst other
socket types have buffers with type `PacketBuffer<'a, 'b,
_>`.
There is an enum over socket types `pub enum Socket<'a, 'b: 'a>`,
which is in turn used by `set::Item` and `SocketSet`. The lifetime
`'b` is not required for `TcpSocket`, but the `Into<Socket>`
implementation for `TCPSocket` specifies the `'static` lifetime for
`'b`.
Therefore using `TCPSocket` in a `SocketSet` currently requires the
lifetime `'b` for other sockets to be `'static` which is unnecessarily
restrictive. This patch fixes this.
The lifetime signature of socket specifies `'b: 'a`, that is `'b`
outlives `'a`. Instead of `'static`, this is also satisfied by
`impl<'a> Into<Socket<'a, 'a>> for TcpSocket<'a>` as `'a` "outlives"
`'a` by definition.
The example
[here](https://gist.github.com/richardeoin/b562e79d0d499e00a8bf4944f00594d9)
fails to compile without this patch.
Closes: #304
Approved by: whitequark
Using move semantics allows an Option to keep track of the
initialization state while satisfying the borrow checker. This replaces
the functionality that the 'consumed' flag had before. It also retains
the smaller object size since the Option of a reference can use the
representation of the null pointer, which is an invalid reference, as a
niche for the None variant.
Closes: #301
Approved by: whitequark
This didn't ever actually cause UB because the drop implementation
should have compiled to a no-op under all conditions; `finish` is
a part of a patchset that never got in. (Even if it didn't, the code
should have been dynamically sound, under all but the most strict
interpretations of Rust's aliasing requirements.)
But it's still a problem, at least because there is a warning for
this potential unsoundness that will become an error in the future.
So everything else aside, we can't use this pattern going forward.
For now, remove the Drop impl, exploiting the fact that `finish`
is a no-op. Going forward this will likely require unsafe code, or
some fundamental change in the way SocketRef is implemented, but
I could not come up with any way to do it. :(
This doesn't affect downstream code because log 0.3.9 is a facade
crate implemented in terms of log 0.4, and so log 0.3 and log 0.4
APIs can be used together.
Fixes a denied lint uncovered on a recent nightly compiler version,
apparently through improved analysis. The code in question is only
compiled with the proto-ipv6 feature and older compiler versions did not
detect the unused qualifier, sometime around 2019-04-23.
Closes: #291
Approved by: whitequark
Improve detection of duplicate ACKs by checking that the segment does
not contain data.
Move implementation from the 'reject unacceptable acknowledgements'
to later in the process function, because a duplicate ACK is not an
'unacceptable' acknowledgement but rather a condition to update state.
Implement more tests to verify the operation of the fast retransmit
implementation.
Related issue: #224Closes: #225
Approved by: whitequark
This optimization makes sure that enqueueing to an empty ring buffer
would never wrap around, in turn ensuring that enqueueing to an empty
packet buffer would never use more than one metadata entry.
Right now, pushing buffer-sized packets into a packet buffer requires
at least two metadata entries, which is surprising and wasteful.
Implement a simple way to discover and respond to three duplicate ACKs
from the reciver of the data. This leads to a fast retransmit of the
last unacknowledged seqment. This is feature is described in [RFC 5681].
Closes: #104Closes: #214
Approved by: whitequark
Dario Nieuwenhuis
Alex Crawford
mustermeiszer
Ryan Summers
Thales Fragoso
whitequark
Lucas Zanela
fdb-hiroshima
Pierre Krieger
Scott Mabin
Richard Meadows
Andreas Molzer
whitequark
Kai Lüke
jhwgh1968
Astro
Dan Robertson
Ole Martin Ruud