mirror of
https://github.com/slackhq/nebula.git
synced 2026-08-15 13:57:03 +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>
103 lines
2.2 KiB
Go
103 lines
2.2 KiB
Go
//go:build !e2e_testing
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// +build !e2e_testing
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package overlay
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import (
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"fmt"
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"io"
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"log/slog"
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"net/netip"
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"os"
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"sync/atomic"
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"github.com/gaissmai/bart"
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"github.com/slackhq/nebula/config"
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"github.com/slackhq/nebula/overlay/tio"
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"github.com/slackhq/nebula/routing"
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"github.com/slackhq/nebula/util"
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)
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type tun struct {
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io.ReadWriteCloser
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fd int
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vpnNetworks []netip.Prefix
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Routes atomic.Pointer[[]Route]
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routeTree atomic.Pointer[bart.Table[routing.Gateways]]
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l *slog.Logger
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}
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func newTunFromFd(c *config.C, l *slog.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
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// XXX Android returns an fd in non-blocking mode which is necessary for shutdown to work properly.
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// Be sure not to call file.Fd() as it will set the fd to blocking mode.
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file := os.NewFile(uintptr(deviceFd), "/dev/net/tun")
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t := &tun{
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ReadWriteCloser: file,
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fd: deviceFd,
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vpnNetworks: vpnNetworks,
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l: l,
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}
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err := t.reload(c, true)
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if err != nil {
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_ = file.Close()
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return nil, err
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}
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c.RegisterReloadCallback(func(c *config.C) {
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err := t.reload(c, false)
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if err != nil {
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util.LogWithContextIfNeeded("failed to reload tun device", err, t.l)
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}
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})
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return t, nil
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}
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func newTun(_ *config.C, _ *slog.Logger, _ []netip.Prefix, _ bool) (*tun, error) {
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return nil, fmt.Errorf("newTun not supported in Android")
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}
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func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
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r, _ := t.routeTree.Load().Lookup(ip)
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return r
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}
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func (t *tun) Activate() error {
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return nil
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}
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func (t *tun) reload(c *config.C, initial bool) error {
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change, routes, err := getAllRoutesFromConfig(c, t.vpnNetworks, initial)
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if err != nil {
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return err
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}
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if !initial && !change {
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return nil
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}
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routeTree, err := makeRouteTree(t.l, routes, false)
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if err != nil {
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return err
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}
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// Teach nebula how to handle the routes
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t.Routes.Store(&routes)
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t.routeTree.Store(routeTree)
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return nil
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}
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func (t *tun) Networks() []netip.Prefix {
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return t.vpnNetworks
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}
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func (t *tun) Name() string {
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return "android"
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}
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func (t *tun) Queues(int) ([]tio.Queue, error) {
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return []tio.Queue{tio.NewSingleQueue(t, defaultBatchBufSize)}, nil
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}
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