proposal: x/net: internal/socket should be public

[anacrolix]

internal/socket allows wrapping existing net.Conn types to access additional system calls. Going via the ipv4/ipv6 route shouldn't be necessary.

I have a net.UDPConn, and want to get at recvmmsg on it.

[bradfitz]

/cc @mikioh

[rsc]

To access additional system calls, as of Go 1.9, net.Conns implement https://golang.org/pkg/syscall/#Conn, which lets you get a syscall.RawConn, which lets you use the fd directly. So maybe exposing internal/socket is not needed?

[anacrolix]

Yes but internal/socket has exposes recvmmsg and recvmsg with a Go interface. syscall.RawConn requires that I do syscalls directly myself, which I'd like to avoid.

[bradfitz]

You can wrap it up into a nice Go package on GitHub, though, and then use that from your pretty code. internal/socket was never written for external consumption.

[anacrolix]

Yes, I understand that. But I think internal/socket has been erroneously concealed from external use by assuming users go through the ipv4/ipv6 packages (unless I missed something). A Go wrapper to recvmsg and recvmmsg should be exposed somewhere, why not here, where the current API is precisely what is needed. If I copy this package to use it elsewhere, I'll risk drifting from the semi-official state of x/net, which evolves to fit the syscall story of the day.

Note there are other socket domains that support msg oriented syscalls, it seems like an appropriate abstraction to expose.

[as]

Was it not already exposed once when Berkely baked it into UNIX? How many generations will endure its abstract fragrance?

[rsc]

syscall.RawConn requires that I do syscalls directly myself, which I'd like to avoid.

It sounds like RawConn lets you do what you need. I understand you wish it was nicer, but we don't want to commit to any of the API in internal/socket.

[mikioh]

The same as #17930, I'm personally fine with having a UDP-specific package in x/net repository. Also fine with considering a comprehensive way; constructing a bit more modern transport layer API such as Post Sockets.