Motivation:
The fix provided in #2407 was subtly wrong. ignoreSIGPIPE, which throws
the error in question, closes the FD on error _except_ on EINVAL from
fcntl, where it instead does not. This inconsistent behaviour is the
source of the bug. Because this behaviour is inconsistent, the fix from
PR #2407 is also inconsistent and can in some cases double-close the
socket.
The actual issue is not as old as I expected: the code can be observed
by reviewing the change in #1598, which incorrectly inserted the error
transformation before the call to close.
Modifications:
- Revert the change from #2407.
- Move the close in ignoreSIGPIPE to before the error check, rather than
after, so we unconditionally execute it.
Result:
More resilient fix.
Motivation:
In some circumstances we can accept a socket that is already closed. In
those cases, creating the underlying Socket type will fail, as
attempting to ignore SIGPIPE will fail. On Apple platforms, this causes
us to leak the accepted socket, and can lead to file descriptor
exhaustion.
Modifications:
- Close the accepted socket if we fail to create a Socket class
Result:
No FD leaks
* 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.
Cory Benfield