warn if invalid routing-lookup is performed

Author: superstes

src/firewall_test/simulator/routes.py

@@ -4,7 +4,7 @@
 from plugins.translate.abstract import StaticRouteRule, StaticRoute
 
 from simulator.packet import PACKET_KINDS
-from utils.logger import log_debug
+from utils.logger import log_debug, log_warn
 
 
 class Router:
@@ -78,6 +78,10 @@ def _get_matching_routes(self, packet: PACKET_KINDS, matching_rules: list[Static
         if src_route:
             route_for = packet.src
 
+        if route_for is None:
+            log_warn('Router', 'Got bad routing-lookup request - this might hint to a plugin-issue!')
+            return []
+
         routes = []
         if len(matching_rules) > 0:
             for rule in matching_rules: