Work on timer teardown + bug fixes

Added waitgroups to peer struct for routine
start / stop synchronisation

src/peer.go

@@ -8,6 +8,10 @@ import (
 	"time"
 )
 
+const (
+	PeerRoutineNumber = 4
+)
+
 type Peer struct {
 	id                          uint
 	mutex                       sync.RWMutex
@@ -34,7 +38,6 @@ type Peer struct {
 		flushNonceQueue    Signal // size 1, empty queued packets
 		messageSend        Signal // size 1, message was send to peer
 		messageReceived    Signal // size 1, authenticated message recv
-		stop               Signal // size 0, stop all goroutines in peer
 	}
 	timer struct {
 		// state related to WireGuard timers
@@ -54,6 +57,12 @@ type Peer struct {
 		outbound chan *QueueOutboundElement // sequential ordering of work
 		inbound  chan *QueueInboundElement  // sequential ordering of work
 	}
+	routines struct {
+		mutex    sync.Mutex     // held when stopping / starting routines
+		starting sync.WaitGroup // routines pending start
+		stopping sync.WaitGroup // routines pending stop
+		stop     Signal         // size 0, stop all goroutines in peer
+	}
 	mac CookieGenerator
 }
 
@@ -121,6 +130,10 @@ func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
 	peer.signal.handshakeCompleted = NewSignal()
 	peer.signal.flushNonceQueue = NewSignal()
 
+	peer.routines.mutex.Lock()
+	peer.routines.stop = NewSignal()
+	peer.routines.mutex.Unlock()
+
 	return peer, nil
 }
 
@@ -156,32 +169,43 @@ func (peer *Peer) String() string {
 	)
 }
 
-/* Starts all routines for a given peer
- *
- * Requires that the caller holds the exclusive peer lock!
- */
-func unsafePeerStart(peer *Peer) {
-	peer.signal.stop.Broadcast()
-	peer.signal.stop = NewSignal()
+func (peer *Peer) Start() {
 
-	var wait sync.WaitGroup
+	peer.routines.mutex.Lock()
+	defer peer.routines.mutex.Lock()
 
-	wait.Add(1)
+	// stop & wait for ungoing routines (if any)
+
+	peer.routines.stop.Broadcast()
+	peer.routines.starting.Wait()
+	peer.routines.stopping.Wait()
+
+	// reset signal and start (new) routines
+
+	peer.routines.stop = NewSignal()
+	peer.routines.starting.Add(PeerRoutineNumber)
+	peer.routines.stopping.Add(PeerRoutineNumber)
 
 	go peer.RoutineNonce()
-	go peer.RoutineTimerHandler(&wait)
+	go peer.RoutineTimerHandler()
 	go peer.RoutineSequentialSender()
 	go peer.RoutineSequentialReceiver()
 
-	wait.Wait()
-}
-
-func (peer *Peer) Start() {
-	peer.mutex.Lock()
-	unsafePeerStart(peer)
-	peer.mutex.Unlock()
+	peer.routines.starting.Wait()
 }
 
 func (peer *Peer) Stop() {
-	peer.signal.stop.Broadcast()
+
+	peer.routines.mutex.Lock()
+	defer peer.routines.mutex.Lock()
+
+	// stop & wait for ungoing routines (if any)
+
+	peer.routines.stop.Broadcast()
+	peer.routines.starting.Wait()
+	peer.routines.stopping.Wait()
+
+	// reset signal (to handle repeated stopping)
+
+	peer.routines.stop = NewSignal()
 }