openflow_input: add inheritance
diff --git a/openflow_input/bsn_get_interfaces b/openflow_input/bsn_get_interfaces
index 01902bc..6f316b0 100644
--- a/openflow_input/bsn_get_interfaces
+++ b/openflow_input/bsn_get_interfaces
@@ -27,7 +27,7 @@
 
 #version any
 
-struct of_bsn_get_interfaces_request {
+struct of_bsn_get_interfaces_request : of_bsn_header {
     uint8_t version;
     uint8_t type == 4;
     uint16_t length;
@@ -44,7 +44,7 @@
     of_ipv4_t ipv4_netmask;
 };
 
-struct of_bsn_get_interfaces_reply {
+struct of_bsn_get_interfaces_reply : of_bsn_header {
     uint8_t version;
     uint8_t type == 4;
     uint16_t length;