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7461dded88
Not great, but lets people working on new ports get going more quickly without having to do everything up front. As the link monitor is getting used more, I felt bad having a useless implementation. Updates #815 Updates #1427 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
73 lines
1.7 KiB
Go
73 lines
1.7 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build !linux,!freebsd,!windows,!darwin android
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package monitor
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import (
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"errors"
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"runtime"
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"sync"
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"time"
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"tailscale.com/types/logger"
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)
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func newOSMon(logf logger.Logf, m *Mon) (osMon, error) {
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return &pollingMon{
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logf: logf,
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m: m,
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stop: make(chan struct{}),
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}, nil
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}
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// pollingMon is a bad but portable implementation of the link monitor
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// that works by polling the interface state every 10 seconds, in lieu
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// of anything to subscribe to. A good implementation
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type pollingMon struct {
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logf logger.Logf
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m *Mon
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closeOnce sync.Once
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stop chan struct{}
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}
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func (pm *pollingMon) Close() error {
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pm.closeOnce.Do(func() {
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close(pm.stop)
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})
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return nil
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}
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func (pm *pollingMon) Receive() (message, error) {
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d := 10 * time.Second
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if runtime.GOOS == "android" {
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// We'll have Android notify the link monitor to wake up earlier,
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// so this can go very slowly there, to save battery.
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// https://github.com/tailscale/tailscale/issues/1427
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d = 10 * time.Minute
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}
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ticker := time.NewTicker(d)
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defer ticker.Stop()
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base := pm.m.InterfaceState()
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for {
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if cur, err := pm.m.interfaceStateUncached(); err == nil && !cur.Equal(base) {
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return unspecifiedMessage{}, nil
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}
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select {
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case <-ticker.C:
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case <-pm.stop:
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return nil, errors.New("stopped")
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}
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}
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}
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// unspecifiedMessage is a minimal message implementation that should not
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// be ignored. In general, OS-specific implementations should use better
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// types and avoid this if they can.
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type unspecifiedMessage struct{}
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func (unspecifiedMessage) ignore() bool { return false }
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