mirror of
https://github.com/slackhq/nebula.git
synced 2026-08-15 09:36:58 +02:00
JackDoan
913a37cfee
Device loses io.ReadWriteCloser + NewMultiQueueReader in favor of Queues(n), which returns up to n tio.Queue objects; platforms without multiqueue hand back their single queue and the interface sizes its reader routines to what it actually got. Queue.Read returns a batch of borrowed packets (single-element for every current backend) so a future backend can deliver more than one packet per syscall without another interface change. The Linux poll/eventfd machinery moves out of tun_linux.go into the new overlay/tio package: nonblocking fds, a shared shutdown eventfd owned by the queue set, and pollfd arrays built on the stack so concurrent writers parked in blockOnWrite no longer share Revents storage. Other platforms wrap their existing one-datagram Read/Write in a singleQueue adapter that owns a private scratch buffer, so multiqueue-by-sharing devices (user, disabled) no longer race concurrent readers on one buffer. This is the tun-interface subset of better-tun-interface-ordering, extracted at 18dc13b with none of the GSO/GRO offload mechanics and no udp/sendmmsg changes. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
46 lines
1.1 KiB
Go
46 lines
1.1 KiB
Go
//go:build linux && !android
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// +build linux,!android
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package tio
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import (
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"os"
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"golang.org/x/sys/unix"
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)
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// blockOn parks the calling goroutine until fd is ready (events is POLLIN for
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// reads, POLLOUT for writes) or shutdownFd signals teardown. It builds the
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// pollfd array on the stack every call, so concurrent callers on the same
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// Queue never share Revents storage.
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//
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// Returns os.ErrClosed when shutdown was signaled (POLLIN on shutdownFd)
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// or either fd reported a problem condition (POLLHUP|POLLNVAL|POLLERR).
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func blockOn(fd, shutdownFd int32, events int16) error {
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const problemFlags = unix.POLLHUP | unix.POLLNVAL | unix.POLLERR
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pfds := [2]unix.PollFd{
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{Fd: fd, Events: events},
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{Fd: shutdownFd, Events: unix.POLLIN},
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}
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var err error
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for {
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_, err = unix.Poll(pfds[:], -1)
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if err != unix.EINTR {
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break
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}
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}
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tunEvents := pfds[0].Revents
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shutdownEvents := pfds[1].Revents
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// Check err before trusting the potentially bogus bits we just got.
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if err != nil {
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return err
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}
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if shutdownEvents&(unix.POLLIN|problemFlags) != 0 {
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return os.ErrClosed
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}
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if tunEvents&problemFlags != 0 {
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return os.ErrClosed
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}
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return nil
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}
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