fix bug

simple-IDS/ids.ml

@@ -29,7 +29,7 @@ let detect_and_output_private packet header frame inter_num output_private outpu
       in
       let options = ipv4_hdr.options in
       let decision_list = Custom_option.get_decision_list ipv4_hdr.dst !attacker_ip_lst in
-      match (decision_list <> [], is_attack, (Cstruct.length options = 12 && Cstruct.get_uint8 options 7 = 1)) with
+      match (decision_list <> [], is_attack, (Cstruct.length options = 12 && Cstruct.get_uint8 options 7 = 1 && Cstruct.get_uint8 options 11 = 0)) with
       | false, false, _ ->
           (* If the packet is NOT in the path of attacks, just look for registration request *)
           Custom_option.read_custom_opt ipv4_hdr.src options;