Fixed a possible crashing bug when used in the wrong way.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19067 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/bin/network/route/route.cpp

@@ -446,6 +446,12 @@ main(int argc, char** argv)
 			add_route(socket, interface, route);
 			break;
 		case RTM_DELETE:
+			if (interface == NULL) {
+				fprintf(stderr, "%s: You need to specify an interface when removing a route.\n",
+					kProgramName);
+				usage(1);
+			}
+
 			delete_route(socket, interface, route);
 			break;