Motivation:
On Linux, the UDP_SEGMENT socket option allows for large buffers to be
written to the kernel and segmented by the kernel (or in some cases the
NIC) into smaller datagrams. This can substantially decrease the number
of syscalls.
This can be set on a per message basis on a per socket basis. This
change adds per socket configuration.
Modifications:
- Add a CNIOLinux function to check whether UDP_SEGMENT is supported on
that particular Linux.
- Add a helper to `System` to check whether UDP_SEGMENT is supported on
the current platform.
- On Linux only:
- add the udp socket option level
- add the udp_segment socket option
- Add the `DatagramSegmentSize` channel option.
- Get/Set the option in `DatagramChannel`
Results:
UDP GSO is supported on Linux.
Co-authored-by: Cory Benfield <lukasa@apple.com>
* RawSocket prototype
* Conform `ProtocolSubtype` to `Hashable`
* Add public `NIOIPProtocol` type
Make `ProtocolSubtype` internal
* Subset of IANA protocols with an RFC
* Add `CustomStringConvertible` to `NIOIPProtocol`
* Add `init(_ rawValue: Int)`
* Rename `NIOBSDSocket.ProtocolSubtype.ip` to `.default`
* Add `NIOBSDSocket.ProtocolSubtype.mptcp`
and remove `NIOBSDSocket.mptcpProtocolSubtype`
Motivation
MPTCP provides multipath capability for TCP connections. This
allows TCP connections to consume multiple independent network
paths, providing devices with a number of capabilities to
improve throughput, latency, or reliability.
MPTCP is not totally transparent, and requires servers to support
the functionality as well as clients. To that end, we should expose
some MPTCP capability.
Importantly, MPTCP uses a number of new socket flags and options.
To enable us to support this when it is available but gracefully fail
when it is not, we've hardcoded a number of Linux kernel constants
instead of relying on libc to expose them. This is safe to do on Linux
because its syscall layer is ABI stable.
Modifications
- Add ClientBootstrap and ServerBootstrap flags for MPTCP
- Plumb MPTCP through the stack
- Add new socket options for MPTCP
Result
MPTCP is supported on Linux
Motivation:
The remaining NIO code really conceptually belongs in a module called
NIOPosix, and NIOCore should really be called NIO. We can't really do
that last step, but we can prepare by pushing the bulk of the remaining
code into a module called NIOPosix.
Modifications:
- Move NIO to NIOPosix
- Make NIO an umbrella module.
Result:
NIOPosix exists.
George Barnett