diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 296a556454e344b2cad71bc508b1fd047ebdf380..05f08695c6c97b760218876384a778d8a9039dd9 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -106,6 +106,7 @@ struct __fdb_entry {
 #define BRIDGE_MODE_VEB		0	/* Default loopback mode */
 #define BRIDGE_MODE_VEPA	1	/* 802.1Qbg defined VEPA mode */
 #define BRIDGE_MODE_SWDEV	2	/* Full switch device offload */
+#define BRIDGE_MODE_UNDEF	0xFFFF  /* mode undefined */
 
 /* Bridge management nested attributes
  * [IFLA_AF_SPEC] = {