Revert "Peer timer teardown"

This reverts commit d73f960aab.

Problems with deadlocking arises due to orphaned packets in per-peer
queues. Additional work on this issue continues in seperate branch.

src/tun.go

@@ -46,13 +46,21 @@ func (device *Device) RoutineTUNEventReader() {
 		}
 
 		if event&TUNEventUp != 0 {
-			logInfo.Println("Interface set up")
-			device.Up()
+			if !device.tun.isUp.Get() {
+				// begin listening for incomming datagrams
+				logInfo.Println("Interface set up")
+				device.tun.isUp.Set(true)
+				updateBind(device)
+			}
 		}
 
 		if event&TUNEventDown != 0 {
-			logInfo.Println("Interface set down")
-			device.Up()
+			if device.tun.isUp.Get() {
+				// stop listening for incomming datagrams
+				logInfo.Println("Interface set down")
+				device.tun.isUp.Set(false)
+				closeBind(device)
+			}
 		}
 	}
 }