diff --git a/c_gen/c_match.py b/c_gen/c_match.py
index c62899d..e15688e 100644
--- a/c_gen/c_match.py
+++ b/c_gen/c_match.py
@@ -286,6 +286,8 @@
     OF_OXM_INDEX_IPV6_ND_TLL    = 33, /* Target link-layer for ND. */
     OF_OXM_INDEX_MPLS_LABEL     = 34, /* MPLS label. */
     OF_OXM_INDEX_MPLS_TC        = 35, /* MPLS TC. */
+
+    OF_OXM_INDEX_BSN_IN_PORTS_128 = 36,
 };
 
 #define OF_OXM_BIT(index) (((uint64_t) 1) << (index))