From b44a0f29f3ed3ed31323027eef864acf20240259 Mon Sep 17 00:00:00 2001 From: Arceliar Date: Sat, 2 Feb 2019 22:18:55 -0600 Subject: [PATCH] send an ack if we receive a packet and don't have any return traffic, keeping a legacy 4-second keep-alive in case there's no traffic at all to send (to be removed later, after nodes have upgraded), ideally we should either remove ReadTimeout or use it for the switch idle timeout instead --- src/util/util.go | 12 ++++++ src/yggdrasil/link.go | 85 +++++++++++++++++++++++++++---------------- 2 files changed, 65 insertions(+), 32 deletions(-) diff --git a/src/util/util.go b/src/util/util.go index 65e6d46..45be3b1 100644 --- a/src/util/util.go +++ b/src/util/util.go @@ -3,6 +3,7 @@ package util // These are misc. utility functions that didn't really fit anywhere else import "runtime" +import "time" // A wrapper around runtime.Gosched() so it doesn't need to be imported elsewhere. func Yield() { @@ -44,3 +45,14 @@ func PutBytes(bs []byte) { default: } } + +// This is a workaround to go's broken timer implementation +func TimerStop(t *time.Timer) bool { + if !t.Stop() { + select { + case <-t.C: + default: + } + } + return true +} diff --git a/src/yggdrasil/link.go b/src/yggdrasil/link.go index 2d2155c..a6c0ccc 100644 --- a/src/yggdrasil/link.go +++ b/src/yggdrasil/link.go @@ -20,6 +20,7 @@ type link struct { mutex sync.RWMutex // protects interfaces below interfaces map[linkInfo]*linkInterface awdl awdl // AWDL interface support + // TODO timeout (to remove from switch), read from config.ReadTimeout } type linkInfo struct { @@ -78,8 +79,6 @@ func (l *link) create(msgIO linkInterfaceMsgIO, name, linkType, local, remote st incoming: incoming, force: force, } - //l.interfaces[intf.name] = &intf - //go intf.start() return &intf, nil } @@ -172,41 +171,49 @@ func (intf *linkInterface) handler() error { go intf.peer.linkLoop() // Start the writer signalReady := make(chan struct{}, 1) + signalSent := make(chan struct{}, 1) + sendAck := make(chan struct{}, 1) go func() { defer close(signalReady) + defer close(signalSent) interval := 4 * time.Second - timer := time.NewTimer(interval) - clearTimer := func() { - if !timer.Stop() { - select { - case <-timer.C: - default: - } + tcpTimer := time.NewTimer(interval) // used for backwards compat with old tcp + defer util.TimerStop(tcpTimer) + send := func(bs []byte) { + intf.msgIO.writeMsg(bs) + select { + case signalSent <- struct{}{}: + default: } } - defer clearTimer() for { // First try to send any link protocol traffic select { case msg := <-intf.peer.linkOut: - intf.msgIO.writeMsg(msg) + send(msg) continue default: } // No protocol traffic to send, so reset the timer - clearTimer() - timer.Reset(interval) + util.TimerStop(tcpTimer) + tcpTimer.Reset(interval) // Now block until something is ready or the timer triggers keepalive traffic select { - case <-timer.C: - intf.msgIO.writeMsg(nil) + case <-tcpTimer.C: + intf.link.core.log.Debugf("Sending (legacy) keep-alive to %s: %s, source %s", + strings.ToUpper(intf.info.linkType), themString, intf.info.local) + send(nil) + case <-sendAck: + intf.link.core.log.Debugf("Sending ack to %s: %s, source %s", + strings.ToUpper(intf.info.linkType), themString, intf.info.local) + send(nil) case msg := <-intf.peer.linkOut: intf.msgIO.writeMsg(msg) case msg, ok := <-out: if !ok { return } - intf.msgIO.writeMsg(msg) + send(msg) util.PutBytes(msg) select { case signalReady <- struct{}{}: @@ -217,27 +224,23 @@ func (intf *linkInterface) handler() error { }() //intf.link.core.switchTable.idleIn <- intf.peer.port // notify switch that we're idle // Used to enable/disable activity in the switch - signalAlive := make(chan struct{}, 1) + signalAlive := make(chan bool, 1) // True = real packet, false = keep-alive defer close(signalAlive) go func() { var isAlive bool var isReady bool - interval := 6 * time.Second // TODO set to ReadTimeout from the config, reset if it gets changed - timer := time.NewTimer(interval) - clearTimer := func() { - if !timer.Stop() { - select { - case <-timer.C: - default: - } - } - } - defer clearTimer() + var ackTimerRunning bool + timeout := 6 * time.Second // TODO set to ReadTimeout from the config, reset if it gets changed + ackTime := time.Second + timer := time.NewTimer(timeout) + defer util.TimerStop(timer) + ackTimer := time.NewTimer(ackTime) + defer util.TimerStop(ackTimer) for { - clearTimer() - timer.Reset(interval) + util.TimerStop(timer) + timer.Reset(timeout) select { - case _, ok := <-signalAlive: + case gotMsg, ok := <-signalAlive: if !ok { return } @@ -249,6 +252,24 @@ func (intf *linkInterface) handler() error { intf.link.core.switchTable.idleIn <- intf.peer.port } } + if gotMsg && !ackTimerRunning { + util.TimerStop(ackTimer) + ackTimer.Reset(ackTime) + ackTimerRunning = true + } + case _, ok := <-signalSent: + // Stop any running ack timer + if !ok { + return + } + util.TimerStop(ackTimer) + ackTimerRunning = false + case <-ackTimer.C: + // We haven't sent anything in the past ackTimeout, so signal a send of a nil packet + select { + case sendAck <- struct{}{}: + default: + } case _, ok := <-signalReady: if !ok { return @@ -275,7 +296,7 @@ func (intf *linkInterface) handler() error { return err } select { - case signalAlive <- struct{}{}: + case signalAlive <- len(msg) > 0: default: } }