diff --git a/openflow_input/bsn_ip_mask b/openflow_input/bsn_ip_mask
index f93c797..c8b3bd8 100644
--- a/openflow_input/bsn_ip_mask
+++ b/openflow_input/bsn_ip_mask
@@ -35,7 +35,7 @@
     uint32_t experimenter;  // bsn 0x005c16c7,
     uint32_t subtype;       // 0
     uint8_t index;
-    uint8_t[3] pad;
+    pad(3);
     uint32_t mask;
 };
 
@@ -47,7 +47,7 @@
     uint32_t experimenter;  // bsn 0x005c16c7,
     uint32_t subtype;       // 1
     uint8_t index;
-    uint8_t[7] pad;
+    pad(7);
 };
 
 struct of_bsn_get_ip_mask_reply {
@@ -58,6 +58,6 @@
     uint32_t experimenter;  // bsn 0x005c16c7,
     uint32_t subtype;       // 2
     uint8_t index;
-    uint8_t[3] pad;
+    pad(3);
     uint32_t mask;
 };