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102 lines
2.4 KiB
102 lines
2.4 KiB
/*
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* Copyright (c) 2013 IBM Corp.
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*
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* Seth Hoenig
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* Allan Stockdill-Mander
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* Mike Robertson
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*/
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package mqtt
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import (
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"errors"
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"time"
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"github.com/eclipse/paho.mqtt.golang/packets"
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)
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func keepalive(c *client) {
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DEBUG.Println(PNG, "keepalive starting")
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receiveInterval := c.options.KeepAlive + (1 * time.Second)
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pingTimer := timer{Timer: time.NewTimer(c.options.KeepAlive)}
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receiveTimer := timer{Timer: time.NewTimer(receiveInterval)}
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pingRespTimer := timer{Timer: time.NewTimer(c.options.PingTimeout)}
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pingRespTimer.Stop()
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for {
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select {
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case <-c.stop:
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DEBUG.Println(PNG, "keepalive stopped")
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c.workers.Done()
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return
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case <-pingTimer.C:
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sendPing(&pingTimer, &pingRespTimer, c)
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case <-c.keepaliveReset:
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DEBUG.Println(NET, "resetting ping timer")
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pingTimer.Reset(c.options.KeepAlive)
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case <-c.pingResp:
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DEBUG.Println(NET, "resetting ping timeout timer")
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pingRespTimer.Stop()
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pingTimer.Reset(c.options.KeepAlive)
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receiveTimer.Reset(receiveInterval)
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case <-c.packetResp:
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DEBUG.Println(NET, "resetting receive timer")
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receiveTimer.Reset(receiveInterval)
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case <-receiveTimer.C:
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receiveTimer.SetRead(true)
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receiveTimer.Reset(receiveInterval)
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sendPing(&pingTimer, &pingRespTimer, c)
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case <-pingRespTimer.C:
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pingRespTimer.SetRead(true)
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CRITICAL.Println(PNG, "pingresp not received, disconnecting")
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c.workers.Done()
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c.internalConnLost(errors.New("pingresp not received, disconnecting"))
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pingTimer.Stop()
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return
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}
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}
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}
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type timer struct {
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*time.Timer
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readFrom bool
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}
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func (t *timer) SetRead(v bool) {
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t.readFrom = v
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}
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func (t *timer) Stop() bool {
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defer t.SetRead(true)
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if !t.Timer.Stop() && !t.readFrom {
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<-t.C
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return false
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}
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return true
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}
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func (t *timer) Reset(d time.Duration) bool {
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defer t.SetRead(false)
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t.Stop()
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return t.Timer.Reset(d)
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}
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func sendPing(pt *timer, rt *timer, c *client) {
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pt.SetRead(true)
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DEBUG.Println(PNG, "keepalive sending ping")
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ping := packets.NewControlPacket(packets.Pingreq).(*packets.PingreqPacket)
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//We don't want to wait behind large messages being sent, the Write call
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//will block until it it able to send the packet.
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ping.Write(c.conn)
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rt.Reset(c.options.PingTimeout)
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}
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