From ac9912345b4da5034ea93f5f245ea2ce04815bd5 Mon Sep 17 00:00:00 2001
From: Mathias Hall-Andersen <mathias@hall-andersen.dk>
Date: Wed, 18 Apr 2018 20:29:48 +0200
Subject: [PATCH] Fixed read from closed channel

A premature waitgroup .Done resulted in reading from closed channel.
This caused a nil-pointer deref & crash.

Added additional debugging when closing routines.
---
 peer.go    |  2 +-
 receive.go | 10 +++++++---
 send.go    | 14 +++++++++++---
 timers.go  | 10 +++++++---
 4 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/peer.go b/peer.go
index 8acdfbc..f10bfbb 100644
--- a/peer.go
+++ b/peer.go
@@ -246,8 +246,8 @@ func (peer *Peer) Stop() {
 
 	// stop & wait for ongoing peer routines
 
-	peer.routines.stop.Broadcast()
 	peer.routines.starting.Wait()
+	peer.routines.stop.Broadcast()
 	peer.routines.stopping.Wait()
 
 	// stop timers
diff --git a/receive.go b/receive.go
index 96ba08d..1045cee 100644
--- a/receive.go
+++ b/receive.go
@@ -500,8 +500,8 @@ func (peer *Peer) RoutineSequentialReceiver() {
 	logError := device.log.Error
 	logDebug := device.log.Debug
 
-	func() {
-		defer peer.routines.stopping.Done()
+	defer func() {
+		peer.routines.stopping.Done()
 		logDebug.Println(peer.String(), ": Routine, Sequential Receiver, Stopped")
 	}()
 
@@ -516,7 +516,11 @@ func (peer *Peer) RoutineSequentialReceiver() {
 		case <-peer.routines.stop.Wait():
 			return
 
-		case elem := <-peer.queue.inbound:
+		case elem, ok := <-peer.queue.inbound:
+
+			if !ok {
+				return
+			}
 
 			// wait for decryption
 
diff --git a/send.go b/send.go
index 5a59f6e..df8efdb 100644
--- a/send.go
+++ b/send.go
@@ -320,13 +320,16 @@ func (device *Device) RoutineEncryption() {
  */
 func (peer *Peer) RoutineSequentialSender() {
 
-	defer peer.routines.stopping.Done()
-
 	device := peer.device
 
 	logDebug := device.log.Debug
 	logDebug.Println("Routine, sequential sender, started for", peer.String())
 
+	defer func() {
+		peer.routines.stopping.Done()
+		logDebug.Println(peer.String(), ": Routine, Sequential sender, Stopped")
+	}()
+
 	peer.routines.starting.Done()
 
 	for {
@@ -337,7 +340,12 @@ func (peer *Peer) RoutineSequentialSender() {
 				"Routine, sequential sender, stopped for", peer.String())
 			return
 
-		case elem := <-peer.queue.outbound:
+		case elem, ok := <-peer.queue.outbound:
+
+			if !ok {
+				return
+			}
+
 			elem.mutex.Lock()
 			if elem.IsDropped() {
 				continue
diff --git a/timers.go b/timers.go
index e118c38..8725570 100644
--- a/timers.go
+++ b/timers.go
@@ -183,13 +183,15 @@ func (peer *Peer) sendNewHandshake() error {
 
 func (peer *Peer) RoutineTimerHandler() {
 
-	defer peer.routines.stopping.Done()
-
 	device := peer.device
 
 	logInfo := device.log.Info
 	logDebug := device.log.Debug
-	logDebug.Println("Routine, timer handler, started for peer", peer.String())
+
+	defer func() {
+		logDebug.Println(peer.String(), ": Routine, Timer handler, Stopped")
+		peer.routines.stopping.Done()
+	}()
 
 	// reset all timers
 
@@ -205,6 +207,8 @@ func (peer *Peer) RoutineTimerHandler() {
 		peer.timer.keepalivePersistent.Reset(duration)
 	}
 
+	logDebug.Println("Routine, timer handler, started for peer", peer.String())
+
 	// signal synchronised setup complete
 
 	peer.routines.starting.Done()