* Recover from EINVAL even if the error is untyped
* Handle fcntl EINVAL error
* Fix EINVAL test
* Rename and deprecate errors
Co-authored-by: Cory Benfield <lukasa@apple.com>
Motivation:
Network congestion can be controlled without packet loss if explicit congestion notification messages are understood.
Modifications:
Receive single and vector paths to get notification and surface.
Send paths for both single and vector sends.
Round trip tests.
Storage for control messages added in a reusable way.
I have tested allocations and they seem to be fine but the allocation tests for vector read and write were not stable enough to sensibly add to CI.
Result:
Explicit Congestion Notifications can be both sent and received.
Motivation:
sendmsg is more powerful - this is paving the way for
Explicit Congestion Notifications to be sent.
Modifications:
Replace the sendto system call with sendmsg up to DatagramChannel.
Result:
Sendmsg will be used to send UDP data.
Motivation:
When attempting to obtain metadata about a read, we need to use recvmsg
in order to obtain that data. While we're using recvmmsg for vector
reads right now, our scalar reads use recvfrom, which does not provide
us with that metadata.
While we're not extracting metadata right now, we may well do so in
future, so we can apply it now.
Modifications:
- Move recvfrom usage to recvmsg.
Result:
We'll be able to extend recvmsg to extract metadata.
* NIO: Add new `BSDSocket` namespace
This starts the split of the POSIX/Linux/Darwin/BSD interfaces and the
BSD Socket interfaces in order to support Windows. The constants on
Windows are not part of the C standard library and need to be explicitly
prefixed. Use the import by name to avoid the `#if` conditions on the
wrapped versions. This will allow us to cleanly cleave the dependency
on the underlying C library.
This change adds a `BSDSocket.OptionLevel` and `BSDSocket.Option` types
which allow us to get proper enumerations for these values and pipe them
throughout the NIO codebase.
* Apply suggestions from code review
Co-Authored-By: Cory Benfield <lukasa@apple.com>
## Motivation:
In SwiftNIO's codebase, most things were always testable just as well as user code is. With one big missing piece: We could never make the `Selector` do arbitrary things to the `Channel` implementations which lead to super expensive to (create, read, understand) integration tests like [`testWriteAndFlushFromReentrantFlushNowTriggeredOutOfWritabilityWhereOuterSaysAllWrittenAndInnerDoesNot `](5dc9083c6a/Tests/NIOTests/StreamChannelsTest.swift (L468-L760)).
## Modification
Add SAL, a 'syscall abstraction layer' which makes it possible to assert all syscalls that come through a `Socket` or the `Selector` by mocking them. It lets the NIO programmer play the kernel in these "SAL tests" which makes it possible to assert the exact syscalls (with their parameters) and decide the syscalls' returns.
## Result
Finally, we're able to write proper unit tests for scenarios where the `Channel` drove the `Selector` incorrectly.
Motivation:
There are use-cases for SwiftNIO where there are no actual sockets but
rather two pipe file descriptors - one for input, one for output.
There's no real reason why SwiftNIO shouldn't work for those.
Modifications:
Add a PipeChannel.
Result:
More use-cases for SwiftNIO.
Timothée Peignier