diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 2cc4644..d120f9f 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -271,6 +271,7 @@
 	OVS_KEY_ATTR_SKB_MARK,  /* u32 skb mark */
 	OVS_KEY_ATTR_TUNNEL,    /* Nested set of ovs_tunnel attributes */
 	OVS_KEY_ATTR_SCTP,      /* struct ovs_key_sctp */
+	OVS_KEY_ATTR_TCP_FLAGS,	/* be16 TCP flags. */
 
 #ifdef __KERNEL__
 	OVS_KEY_ATTR_IPV4_TUNNEL,  /* struct ovs_key_ipv4_tunnel */