mac80211: add ieee80211_is_any_nullfunc()

commit 08a5bdde ("mac80211: consider QoS Null frames for STA_NULLFUNC_ACKED")
Fixed a bug where we failed to take into account a
nullfunc frame can be either non-QoS or QoS. It turns out
there is at least one more bug in
ieee80211_sta_tx_notify(), introduced in
commit 7b6ddeaf ("mac80211: use QoS NDP for AP probing"),
where we forgot to check for the QoS variant and so
assumed the QoS nullfunc frame never went out

Fix this by adding a helper ieee80211_is_any_nullfunc()
which consolidates the check for non-QoS and QoS nullfunc
frames. Replace existing compound conditionals and add a
couple more missing checks for QoS variant.
Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
Link: https://lore.kernel.org/r/20200114055940.18502-3-thomas@adapt-ip.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

include/linux/ieee80211.h

@@ -619,6 +619,15 @@ static inline bool ieee80211_is_qos_nullfunc(__le16 fc)
 	       cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_QOS_NULLFUNC);
 }
 
+/**
+ * ieee80211_is_any_nullfunc - check if frame is regular or QoS nullfunc frame
+ * @fc: frame control bytes in little-endian byteorder
+ */
+static inline bool ieee80211_is_any_nullfunc(__le16 fc)
+{
+	return (ieee80211_is_nullfunc(fc) || ieee80211_is_qos_nullfunc(fc));
+}
+
 /**
  * ieee80211_is_bufferable_mmpdu - check if frame is bufferable MMPDU
  * @fc: frame control field in little-endian byteorder

net/mac80211/mlme.c

@@ -2460,7 +2460,7 @@ void ieee80211_sta_tx_notify(struct ieee80211_sub_if_data *sdata,
 	if (!ieee80211_is_data(hdr->frame_control))
 	    return;
 
-	if (ieee80211_is_nullfunc(hdr->frame_control) &&
+	if (ieee80211_is_any_nullfunc(hdr->frame_control) &&
 	    sdata->u.mgd.probe_send_count > 0) {
 		if (ack)
 			ieee80211_sta_reset_conn_monitor(sdata);

net/mac80211/rx.c

@@ -1450,8 +1450,7 @@ ieee80211_rx_h_check_dup(struct ieee80211_rx_data *rx)
 		return RX_CONTINUE;
 
 	if (ieee80211_is_ctl(hdr->frame_control) ||
-	    ieee80211_is_nullfunc(hdr->frame_control) ||
-	    ieee80211_is_qos_nullfunc(hdr->frame_control) ||
+	    ieee80211_is_any_nullfunc(hdr->frame_control) ||
 	    is_multicast_ether_addr(hdr->addr1))
 		return RX_CONTINUE;
 
@@ -1838,8 +1837,7 @@ ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
 	 * Drop (qos-)data::nullfunc frames silently, since they
 	 * are used only to control station power saving mode.
 	 */
-	if (ieee80211_is_nullfunc(hdr->frame_control) ||
-	    ieee80211_is_qos_nullfunc(hdr->frame_control)) {
+	if (ieee80211_is_any_nullfunc(hdr->frame_control)) {
 		I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
 
 		/*
@@ -2319,7 +2317,7 @@ static int ieee80211_drop_unencrypted(struct ieee80211_rx_data *rx, __le16 fc)
 
 	/* Drop unencrypted frames if key is set. */
 	if (unlikely(!ieee80211_has_protected(fc) &&
-		     !ieee80211_is_nullfunc(fc) &&
+		     !ieee80211_is_any_nullfunc(fc) &&
 		     ieee80211_is_data(fc) && rx->key))
 		return -EACCES;
 

net/mac80211/status.c

@@ -643,8 +643,7 @@ static void ieee80211_report_ack_skb(struct ieee80211_local *local,
 		rcu_read_lock();
 		sdata = ieee80211_sdata_from_skb(local, skb);
 		if (sdata) {
-			if (ieee80211_is_nullfunc(hdr->frame_control) ||
-			    ieee80211_is_qos_nullfunc(hdr->frame_control))
+			if (ieee80211_is_any_nullfunc(hdr->frame_control))
 				cfg80211_probe_status(sdata->dev, hdr->addr1,
 						      cookie, acked,
 						      info->status.ack_signal,
@@ -1061,7 +1060,7 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw,
 			I802_DEBUG_INC(local->dot11FailedCount);
 	}
 
-	if ((ieee80211_is_nullfunc(fc) || ieee80211_is_qos_nullfunc(fc)) &&
+	if (ieee80211_is_any_nullfunc(fc) &&
 	    ieee80211_has_pm(fc) &&
 	    ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS) &&
 	    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&

net/mac80211/tx.c

@@ -297,7 +297,7 @@ ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx)
 	if (unlikely(test_bit(SCAN_SW_SCANNING, &tx->local->scanning)) &&
 	    test_bit(SDATA_STATE_OFFCHANNEL, &tx->sdata->state) &&
 	    !ieee80211_is_probe_req(hdr->frame_control) &&
-	    !ieee80211_is_nullfunc(hdr->frame_control))
+	    !ieee80211_is_any_nullfunc(hdr->frame_control))
 		/*
 		 * When software scanning only nullfunc frames (to notify
 		 * the sleep state to the AP) and probe requests (for the