diff --git a/proto/ospf/ospf.h b/proto/ospf/ospf.h
index e705b88b..45dd7056 100644
--- a/proto/ospf/ospf.h
+++ b/proto/ospf/ospf.h
@@ -319,13 +319,13 @@ struct immsb
   u8 i:1;
   u8 padding:5;
 #endif
-};
+}__attribute__((packed));;
 
 union imms
 {
   u8 byte;
   struct immsb bit;
-};
+}__attribute__((packed));;
 #define DBDES_MS 1
 #define DBDES_M 2
 #define DBDES_I 4