From 6778b29fc0025ee99c9916fbed74216afb817176 Mon Sep 17 00:00:00 2001
From: Julien Duponchelle <julien@gns3.net>
Date: Fri, 6 Jan 2017 09:33:10 +0100
Subject: [PATCH] Prevent a crash when you close a dynamips node and create a
 link at the same time

Fix #853
---
 gns3server/compute/dynamips/nios/nio_udp.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gns3server/compute/dynamips/nios/nio_udp.py b/gns3server/compute/dynamips/nios/nio_udp.py
index c7c2b656..5b459771 100644
--- a/gns3server/compute/dynamips/nios/nio_udp.py
+++ b/gns3server/compute/dynamips/nios/nio_udp.py
@@ -49,7 +49,8 @@ class NIOUDP(NIO):
 
     @asyncio.coroutine
     def create(self):
-
+        if not self._hypervisor:
+            return
         yield from self._hypervisor.send("nio create_udp {name} {lport} {rhost} {rport}".format(name=self._name,
                                                                                                 lport=self._lport,
                                                                                                 rhost=self._rhost,