mirror of
https://github.com/slackhq/nebula.git
synced 2026-08-15 13:16:58 +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>
91 lines
1.8 KiB
Go
91 lines
1.8 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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"encoding/binary"
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"errors"
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"fmt"
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"sync/atomic"
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"golang.org/x/sys/unix"
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)
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type pollQueueSet struct {
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pq []*Poll
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// pqi is exactly the same as pq, but stored as the interface type
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pqi []Queue
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shutdownFd int
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closed atomic.Bool
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}
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func NewPollQueueSet() (QueueSet, error) {
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shutdownFd, err := unix.Eventfd(0, unix.EFD_NONBLOCK|unix.EFD_CLOEXEC)
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if err != nil {
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return nil, fmt.Errorf("failed to create eventfd: %w", err)
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}
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out := &pollQueueSet{
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pq: []*Poll{},
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pqi: []Queue{},
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shutdownFd: shutdownFd,
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}
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return out, nil
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}
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func (c *pollQueueSet) Queues() []Queue {
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return c.pqi
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}
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func (c *pollQueueSet) Add(fd int) error {
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x, err := newPoll(fd, c.shutdownFd)
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if err != nil {
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return err
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}
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c.pq = append(c.pq, x)
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c.pqi = append(c.pqi, x)
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return nil
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}
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func (c *pollQueueSet) wakeForShutdown() error {
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var buf [8]byte
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binary.NativeEndian.PutUint64(buf[:], 1)
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_, err := unix.Write(int(c.shutdownFd), buf[:])
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return err
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}
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func (c *pollQueueSet) Close() error {
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if c.closed.Swap(true) {
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return nil
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}
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errs := []error{}
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// Wake any reader blocked in poll so it observes POLLIN on the shutdown
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// eventfd and returns os.ErrClosed.
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if err := c.wakeForShutdown(); err != nil {
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errs = append(errs, err)
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}
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// Close the per-queue tun fds; this also unblocks any in-flight reads.
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// The per-queue Close deliberately leaves shutdownFd alone - it belongs
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// to this container.
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for _, x := range c.pq {
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if err := x.Close(); err != nil {
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errs = append(errs, err)
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}
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}
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// Close the shutdown eventfd last: every reader's pollfd set references
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// it, so it must outlive the wake + per-queue teardown above.
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if err := unix.Close(c.shutdownFd); err != nil {
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errs = append(errs, err)
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}
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c.shutdownFd = -1
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return errors.Join(errs...)
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}
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