disable idle nodes in the switch instead of killing the connection entirely. this implementation is ugly, but i think it maybe works

go.mod

@@ -2,10 +2,10 @@ module github.com/yggdrasil-network/yggdrasil-go
 
 require (
 	github.com/docker/libcontainer v2.2.1+incompatible
+	github.com/gologme/log v0.0.0-20181207131047-4e5d8ccb38e8
 	github.com/hjson/hjson-go v0.0.0-20181010104306-a25ecf6bd222
 	github.com/kardianos/minwinsvc v0.0.0-20151122163309-cad6b2b879b0
 	github.com/mitchellh/mapstructure v1.1.2
-	github.com/gologme/log v0.0.0-20181207131047-4e5d8ccb38e8
 	github.com/songgao/packets v0.0.0-20160404182456-549a10cd4091
 	github.com/yggdrasil-network/water v0.0.0-20180615095340-f732c88f34ae
 	golang.org/x/crypto v0.0.0-20181203042331-505ab145d0a9

go.sum

@@ -1,5 +1,7 @@
 github.com/docker/libcontainer v2.2.1+incompatible h1:++SbbkCw+X8vAd4j2gOCzZ2Nn7s2xFALTf7LZKmM1/0=
 github.com/docker/libcontainer v2.2.1+incompatible/go.mod h1:osvj61pYsqhNCMLGX31xr7klUBhHb/ZBuXS0o1Fvwbw=
+github.com/gologme/log v0.0.0-20181207131047-4e5d8ccb38e8 h1:WD8iJ37bRNwvETMfVTusVSAi0WdXTpfNVGY2aHycNKY=
+github.com/gologme/log v0.0.0-20181207131047-4e5d8ccb38e8/go.mod h1:gq31gQ8wEHkR+WekdWsqDuf8pXTUZA9BnnzTuPz1Y9U=
 github.com/hjson/hjson-go v0.0.0-20181010104306-a25ecf6bd222 h1:xmvkbxXDeN1ffWq8kvrhyqVYAO2aXuRBsbpxVTR+JyU=
 github.com/hjson/hjson-go v0.0.0-20181010104306-a25ecf6bd222/go.mod h1:qsetwF8NlsTsOTwZTApNlTCerV+b2GjYRRcIk4JMFio=
 github.com/kardianos/minwinsvc v0.0.0-20151122163309-cad6b2b879b0 h1:YnZmFjg0Nvk8851WTVWlqMC1ecJH07Ctz+Ezxx4u54g=
@@ -18,5 +20,3 @@ golang.org/x/sys v0.0.0-20181206074257-70b957f3b65e h1:njOxP/wVblhCLIUhjHXf6X+dz
 golang.org/x/sys v0.0.0-20181206074257-70b957f3b65e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-github.com/gologme/log v0.0.0-20181207131047-4e5d8ccb38e8 h1:WD8iJ37bRNwvETMfVTusVSAi0WdXTpfNVGY2aHycNKY=
-github.com/gologme/log v0.0.0-20181207131047-4e5d8ccb38e8/go.mod h1:gq31gQ8wEHkR+WekdWsqDuf8pXTUZA9BnnzTuPz1Y9U=

src/yggdrasil/link.go

@@ -146,7 +146,9 @@ func (intf *linkInterface) handler() error {
 	intf.peer.close = func() { intf.msgIO.close() }
 	go intf.peer.linkLoop()
 	// Start the writer
+	signalReady := make(chan struct{}, 1)
 	go func() {
+		defer close(signalReady)
 		interval := 4 * time.Second
 		timer := time.NewTimer(interval)
 		clearTimer := func() {
@@ -181,15 +183,63 @@ func (intf *linkInterface) handler() error {
 				}
 				intf.msgIO.writeMsg(msg)
 				util.PutBytes(msg)
-				if true {
-					// TODO *don't* do this if we're not reading any traffic
-					// In such a case, the reader is responsible for resetting it the next time we read something
-					intf.link.core.switchTable.idleIn <- intf.peer.port
+				select {
+				case signalReady <- struct{}{}:
+				default:
 				}
 			}
 		}
 	}()
-	intf.link.core.switchTable.idleIn <- intf.peer.port // notify switch that we're idle
+	//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)
+	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()
+		for {
+			clearTimer()
+			timer.Reset(interval)
+			select {
+			case _, ok := <-signalAlive:
+				if !ok {
+					return
+				}
+				if !isAlive {
+					isAlive = true
+					if !isReady {
+						// (Re-)enable in the switch
+						isReady = true
+						intf.link.core.switchTable.idleIn <- intf.peer.port
+					}
+				}
+			case _, ok := <-signalReady:
+				if !ok {
+					return
+				}
+				if !isAlive || !isReady {
+					// Disable in the switch
+					isReady = false
+				} else {
+					// Keep enabled in the switch
+					intf.link.core.switchTable.idleIn <- intf.peer.port
+				}
+			case <-timer.C:
+				isAlive = false
+			}
+		}
+	}()
 	// Run reader loop
 	for {
 		msg, err := intf.msgIO.readMsg()
@@ -199,6 +249,10 @@ func (intf *linkInterface) handler() error {
 		if err != nil {
 			return err
 		}
+		select {
+		case signalAlive <- struct{}{}:
+		default:
+		}
 	}
 	////////////////////////////////////////////////////////////////////////////////
 	return nil