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2716250ee8
And enable U1000 check in staticcheck. Updates #cleanup Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
191 lines
5.3 KiB
Go
191 lines
5.3 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package netmon
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import (
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"context"
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"errors"
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"strings"
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"sync"
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"time"
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"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
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"tailscale.com/net/tsaddr"
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"tailscale.com/types/logger"
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)
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var (
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errClosed = errors.New("closed")
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)
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type eventMessage struct {
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eventType string
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}
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func (eventMessage) ignore() bool { return false }
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type winMon struct {
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logf logger.Logf
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ctx context.Context
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cancel context.CancelFunc
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isActive func() bool
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messagec chan eventMessage
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addressChangeCallback *winipcfg.UnicastAddressChangeCallback
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routeChangeCallback *winipcfg.RouteChangeCallback
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mu sync.Mutex
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lastLog time.Time // time we last logged about any windows change event
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// noDeadlockTicker exists just to have something scheduled as
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// far as the Go runtime is concerned. Otherwise "tailscaled
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// debug --monitor" thinks it's deadlocked with nothing to do,
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// as Go's runtime doesn't know about callbacks registered with
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// Windows.
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noDeadlockTicker *time.Ticker
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}
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func newOSMon(logf logger.Logf, pm *Monitor) (osMon, error) {
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m := &winMon{
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logf: logf,
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isActive: pm.isActive,
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messagec: make(chan eventMessage, 1),
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noDeadlockTicker: time.NewTicker(5000 * time.Hour), // arbitrary
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}
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m.ctx, m.cancel = context.WithCancel(context.Background())
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var err error
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m.addressChangeCallback, err = winipcfg.RegisterUnicastAddressChangeCallback(m.unicastAddressChanged)
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if err != nil {
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m.logf("winipcfg.RegisterUnicastAddressChangeCallback error: %v", err)
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m.cancel()
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return nil, err
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}
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m.routeChangeCallback, err = winipcfg.RegisterRouteChangeCallback(m.routeChanged)
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if err != nil {
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m.addressChangeCallback.Unregister()
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m.logf("winipcfg.RegisterRouteChangeCallback error: %v", err)
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m.cancel()
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return nil, err
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}
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return m, nil
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}
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func (m *winMon) IsInterestingInterface(iface string) bool { return true }
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func (m *winMon) Close() (ret error) {
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m.cancel()
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m.noDeadlockTicker.Stop()
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if m.addressChangeCallback != nil {
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if err := m.addressChangeCallback.Unregister(); err != nil {
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m.logf("addressChangeCallback.Unregister error: %v", err)
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ret = err
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} else {
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m.addressChangeCallback = nil
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}
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}
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if m.routeChangeCallback != nil {
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if err := m.routeChangeCallback.Unregister(); err != nil {
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m.logf("routeChangeCallback.Unregister error: %v", err)
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ret = err
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} else {
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m.routeChangeCallback = nil
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}
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}
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return
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}
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func (m *winMon) Receive() (message, error) {
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if m.ctx.Err() != nil {
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m.logf("Receive call on closed monitor")
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return nil, errClosed
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}
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t0 := time.Now()
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select {
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case msg := <-m.messagec:
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now := time.Now()
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m.mu.Lock()
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sinceLast := now.Sub(m.lastLog)
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m.lastLog = now
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m.mu.Unlock()
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// If it's either been awhile since we last logged
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// anything, or if this some route/addr that's not
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// about a Tailscale IP ("ts" prefix), then log. This
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// is mainly limited to suppress the flood about our own
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// route updates after connecting to a large tailnet
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// and all the IPv4 /32 routes.
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if sinceLast > 5*time.Second || !strings.HasPrefix(msg.eventType, "ts") {
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m.logf("got windows change event after %v: evt=%s", time.Since(t0).Round(time.Millisecond), msg.eventType)
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}
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return msg, nil
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case <-m.ctx.Done():
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return nil, errClosed
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}
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}
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// unicastAddressChanged is the callback we register with Windows to call when unicast address changes.
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func (m *winMon) unicastAddressChanged(_ winipcfg.MibNotificationType, row *winipcfg.MibUnicastIPAddressRow) {
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if !m.isActive() {
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// Avoid starting a goroutine that sends events to messagec,
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// or sending messages to messagec directly, if the monitor
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// hasn't started and Receive is not yet reading from messagec.
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//
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// Doing so can lead to goroutine leaks or deadlocks, especially
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// if the monitor is never started.
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return
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}
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what := "addr"
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if ip := row.Address.Addr(); ip.IsValid() && tsaddr.IsTailscaleIP(ip.Unmap()) {
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what = "tsaddr"
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}
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// start a goroutine to finish our work, to return to Windows out of this callback
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go m.somethingChanged(what)
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}
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// routeChanged is the callback we register with Windows to call when route changes.
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func (m *winMon) routeChanged(_ winipcfg.MibNotificationType, row *winipcfg.MibIPforwardRow2) {
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if !m.isActive() {
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// Avoid starting a goroutine that sends events to messagec,
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// or sending messages to messagec directly, if the monitor
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// hasn't started and Receive is not yet reading from messagec.
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//
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// Doing so can lead to goroutine leaks or deadlocks, especially
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// if the monitor is never started.
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return
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}
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what := "route"
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ip := row.DestinationPrefix.Prefix().Addr().Unmap()
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if ip.IsValid() && tsaddr.IsTailscaleIP(ip) {
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what = "tsroute"
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}
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// start a goroutine to finish our work, to return to Windows out of this callback
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go m.somethingChanged(what)
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}
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// somethingChanged gets called from OS callbacks whenever address or route changes.
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func (m *winMon) somethingChanged(evt string) {
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select {
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case <-m.ctx.Done():
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return
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case m.messagec <- eventMessage{eventType: evt}:
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return
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}
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}
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// isActive reports whether this monitor has been started and not yet closed.
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func (m *Monitor) isActive() bool {
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m.mu.Lock()
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defer m.mu.Unlock()
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return m.started && !m.closed
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}
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