From 281f06e63952e3ff61eaddc61dd7c9b96f332070 Mon Sep 17 00:00:00 2001
From: Tommaso Pecorella <tommaso.pecorella@unifi.it>
Date: Tue, 21 Jan 2014 22:52:52 +0100
Subject: [PATCH] Bug 1841 - FlowMonitor fails to install if IPv4 is not
 installed in the node

---
 src/flow-monitor/helper/flow-monitor-helper.cc | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/flow-monitor/helper/flow-monitor-helper.cc b/src/flow-monitor/helper/flow-monitor-helper.cc
index a2d0a5b1a..1b03b628c 100644
--- a/src/flow-monitor/helper/flow-monitor-helper.cc
+++ b/src/flow-monitor/helper/flow-monitor-helper.cc
@@ -81,9 +81,13 @@ FlowMonitorHelper::Install (Ptr<Node> node)
 {
   Ptr<FlowMonitor> monitor = GetMonitor ();
   Ptr<FlowClassifier> classifier = GetClassifier ();
-  Ptr<Ipv4FlowProbe> probe = Create<Ipv4FlowProbe> (monitor,
-                                                    DynamicCast<Ipv4FlowClassifier> (classifier),
-                                                    node);
+  Ptr<Ipv4L3Protocol> ipv4 = node->GetObject<Ipv4L3Protocol> ();
+  if (ipv4)
+    {
+      Ptr<Ipv4FlowProbe> probe = Create<Ipv4FlowProbe> (monitor,
+                                                        DynamicCast<Ipv4FlowClassifier> (classifier),
+                                                        node);
+    }
   return m_flowMonitor;
 }