diff --git a/sys/dev/ath/if_ath_tx.c b/sys/dev/ath/if_ath_tx.c
index 1ec23972f283..1559b66a7c7d 100644
--- a/sys/dev/ath/if_ath_tx.c
+++ b/sys/dev/ath/if_ath_tx.c
@@ -2050,7 +2050,7 @@ ath_tx_start(struct ath_softc *sc, struct ieee80211_node *ni,
 		 */
 		if (IEEE80211_QOS_HAS_SEQ(wh) &&
 		    (! IEEE80211_IS_MULTICAST(wh->i_addr1)) &&
-		    (subtype != IEEE80211_FC0_SUBTYPE_QOS_NULL)) {
+		    (! IEEE80211_IS_QOS_NULL(wh))) {
 			bf->bf_state.bfs_dobaw = 1;
 		}
 	}
@@ -2991,7 +2991,7 @@ ath_tx_tid_seqno_assign(struct ath_softc *sc, struct ieee80211_node *ni,
 	 * RX side.
 	 */
 	subtype = wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK;
-	if (subtype == IEEE80211_FC0_SUBTYPE_QOS_NULL) {
+	if (IEEE80211_IS_QOS_NULL(wh)) {
 		/* XXX no locking for this TID? This is a bit of a problem. */
 		seqno = ni->ni_txseqs[IEEE80211_NONQOS_TID];
 		INCR(ni->ni_txseqs[IEEE80211_NONQOS_TID], IEEE80211_SEQ_RANGE);
diff --git a/sys/net80211/ieee80211.h b/sys/net80211/ieee80211.h
index eb83d0a40a33..e62b8c16d68f 100644
--- a/sys/net80211/ieee80211.h
+++ b/sys/net80211/ieee80211.h
@@ -274,6 +274,16 @@ struct ieee80211_qosframe_addr4 {
 	 IEEE80211_FC0_TYPE_DATA,			\
 	 IEEE80211_FC0_SUBTYPE_QOS_DATA))
 
+/*
+ * Return true if this frame is a QoS NULL data frame.
+ */
+#define	IEEE80211_IS_QOS_NULL(wh)			\
+	(IEEE80211_IS_FC0_CHECK_VER_TYPE_SUBTYPE(wh,	\
+	 IEEE80211_FC0_VERSION_0,			\
+	 IEEE80211_FC0_TYPE_DATA,			\
+	 IEEE80211_FC0_SUBTYPE_QOS_NULL))
+
+
 #define	IEEE80211_FC1_DIR_MASK			0x03
 #define	IEEE80211_FC1_DIR_NODS			0x00	/* STA->STA */
 #define	IEEE80211_FC1_DIR_TODS			0x01	/* STA->AP  */