75 lines
2.3 KiB
Go
75 lines
2.3 KiB
Go
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/*
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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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"io"
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"sync/atomic"
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"time"
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"github.com/eclipse/paho.mqtt.golang/packets"
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)
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// keepalive - Send ping when connection unused for set period
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// connection passed in to avoid race condition on shutdown
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func keepalive(c *client, conn io.Writer) {
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defer c.workers.Done()
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DEBUG.Println(PNG, "keepalive starting")
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var checkInterval int64
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var pingSent time.Time
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if c.options.KeepAlive > 10 {
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checkInterval = 5
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} else {
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checkInterval = c.options.KeepAlive / 2
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}
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intervalTicker := time.NewTicker(time.Duration(checkInterval * int64(time.Second)))
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defer intervalTicker.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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return
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case <-intervalTicker.C:
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lastSent := c.lastSent.Load().(time.Time)
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lastReceived := c.lastReceived.Load().(time.Time)
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DEBUG.Println(PNG, "ping check", time.Since(lastSent).Seconds())
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if time.Since(lastSent) >= time.Duration(c.options.KeepAlive*int64(time.Second)) || time.Since(lastReceived) >= time.Duration(c.options.KeepAlive*int64(time.Second)) {
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if atomic.LoadInt32(&c.pingOutstanding) == 0 {
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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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atomic.StoreInt32(&c.pingOutstanding, 1)
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if err := ping.Write(conn); err != nil {
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ERROR.Println(PNG, err)
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}
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c.lastSent.Store(time.Now())
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pingSent = time.Now()
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}
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}
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if atomic.LoadInt32(&c.pingOutstanding) > 0 && time.Since(pingSent) >= c.options.PingTimeout {
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CRITICAL.Println(PNG, "pingresp not received, disconnecting")
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c.internalConnLost(errors.New("pingresp not received, disconnecting")) // no harm in calling this if the connection is already down (or shutdown is in progress)
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return
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}
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}
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}
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}
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