110 lines
2.7 KiB
Go
110 lines
2.7 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package tstun
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import (
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"fmt"
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"sync"
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"time"
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"github.com/tailscale/wireguard-go/tun"
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"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
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"tailscale.com/types/logger"
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)
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// ifaceWatcher waits for an interface to be up.
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type ifaceWatcher struct {
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logf logger.Logf
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luid winipcfg.LUID
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mu sync.Mutex // guards following
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done bool
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sig chan bool
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}
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// callback is the callback we register with Windows to call when IP interface changes.
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func (iw *ifaceWatcher) callback(notificationType winipcfg.MibNotificationType, iface *winipcfg.MibIPInterfaceRow) {
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// Probably should check only when MibParameterNotification, but just in case included MibAddInstance also.
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if notificationType == winipcfg.MibParameterNotification || notificationType == winipcfg.MibAddInstance {
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// Out of paranoia, start a goroutine to finish our work, to return to Windows out of this callback.
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go iw.isUp()
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}
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}
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func (iw *ifaceWatcher) isUp() bool {
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iw.mu.Lock()
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defer iw.mu.Unlock()
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if iw.done {
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// We already know that it's up
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return true
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}
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if iw.getOperStatus() != winipcfg.IfOperStatusUp {
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return false
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}
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iw.done = true
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iw.sig <- true
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return true
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}
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func (iw *ifaceWatcher) getOperStatus() winipcfg.IfOperStatus {
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ifc, err := iw.luid.Interface()
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if err != nil {
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iw.logf("iw.luid.Interface error: %v", err)
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return 0
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}
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return ifc.OperStatus
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}
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func waitInterfaceUp(iface tun.Device, timeout time.Duration, logf logger.Logf) error {
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iw := &ifaceWatcher{
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luid: winipcfg.LUID(iface.(*tun.NativeTun).LUID()),
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logf: logger.WithPrefix(logf, "waitInterfaceUp: "),
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}
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// Just in case check the status first
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if iw.getOperStatus() == winipcfg.IfOperStatusUp {
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iw.logf("TUN interface already up; no need to wait")
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return nil
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}
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iw.sig = make(chan bool, 1)
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cb, err := winipcfg.RegisterInterfaceChangeCallback(iw.callback)
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if err != nil {
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iw.logf("RegisterInterfaceChangeCallback error: %v", err)
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return err
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}
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defer cb.Unregister()
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t0 := time.Now()
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expires := t0.Add(timeout)
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ticker := time.NewTicker(10 * time.Second)
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defer ticker.Stop()
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for {
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iw.logf("waiting for TUN interface to come up...")
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select {
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case <-iw.sig:
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iw.logf("TUN interface is up after %v", time.Since(t0))
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return nil
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case <-ticker.C:
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}
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if iw.isUp() {
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// Very unlikely to happen - either NotifyIpInterfaceChange doesn't work
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// or it came up in the same moment as tick. Indicate this in the log message.
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iw.logf("TUN interface is up after %v (on poll, without notification)", time.Since(t0))
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return nil
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}
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if expires.Before(time.Now()) {
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iw.logf("timeout waiting %v for TUN interface to come up", timeout)
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return fmt.Errorf("timeout waiting for TUN interface to come up")
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}
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}
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}
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