Ipv4NetworkConfigurator: Extended static multicast routes with an add…

…itional route for the leaf nodes with no output interfaces.

This prevents packets being reported as dropped because no route is found even though
the packets are delivered locally.

src/inet/networklayer/configurator/ipv4/Ipv4NetworkConfigurator.cc

@@ -1933,13 +1933,11 @@ void Ipv4NetworkConfigurator::addStaticMulticastRoutes(Topology& topology, Node
     InterfaceInfo *inInterfaceInfo = nullptr;
     InterfaceInfo *outInterfaceInfo = nullptr;
     Node *node = receiverNode;
-    while (node != sourceNode && node->getNumPaths() > 0) {
+    while (true) {
         auto link = (Link *)node->getPath(0);
-        outInterfaceInfo = static_cast<InterfaceInfo *>(link->destinationInterfaceInfo);
-        node = (Node *)link->getLinkOutRemoteNode();
-        inInterfaceInfo = node == sourceNode ? nullptr : static_cast<InterfaceInfo *>(((Link *)node->getPath(0))->sourceInterfaceInfo);
+        inInterfaceInfo = node == sourceNode ? nullptr : static_cast<InterfaceInfo *>(link->sourceInterfaceInfo);
         ASSERT(inInterfaceInfo == nullptr || inInterfaceInfo->node == node);
-        ASSERT(outInterfaceInfo->node == node);
+        ASSERT(outInterfaceInfo == nullptr || outInterfaceInfo->node == node);
 
         Ipv4Address origin = Ipv4Address::UNSPECIFIED_ADDRESS;
         Ipv4Address originNetmask = Ipv4Address::UNSPECIFIED_ADDRESS;
@@ -1973,15 +1971,25 @@ void Ipv4NetworkConfigurator::addStaticMulticastRoutes(Topology& topology, Node
             node->staticMulticastRoutes.push_back(route);
         }
 
-        bool foundOutInterface = false;
-        for (unsigned int i = 0; i < route->getNumOutInterfaces(); i++)
-            if (route->getOutInterface(i)->getInterface() == outInterfaceInfo->networkInterface) {
-                foundOutInterface = true;
-                break;
+        if (outInterfaceInfo != nullptr) {
+            bool foundOutInterface = false;
+            for (unsigned int i = 0; i < route->getNumOutInterfaces(); i++) {
+                if (route->getOutInterface(i)->getInterface() == outInterfaceInfo->networkInterface) {
+                    foundOutInterface = true;
+                    break;
+                }
+            }
+            if (!foundOutInterface) {
+                route->addOutInterface(new Ipv4MulticastRoute::OutInterface(outInterfaceInfo->networkInterface, false /*TODOisLeaf*/));
+                EV_INFO << "Extending static multicast route " << *route << " in " << node->module->getFullPath() << endl;
             }
-        if (!foundOutInterface) {
-            route->addOutInterface(new Ipv4MulticastRoute::OutInterface(outInterfaceInfo->networkInterface, false /*TODOisLeaf*/));
-            EV_INFO << "Extending static multicast route " << *route << " in " << node->module->getFullPath() << endl;
+        }
+
+        if (node == sourceNode || node->getNumPaths() == 0)
+            break;
+        else {
+            outInterfaceInfo = static_cast<InterfaceInfo *>(link->destinationInterfaceInfo);
+            node = (Node *)link->getLinkOutRemoteNode();
         }
     }
 }