mac80211: QoS multicast frames have No Ack policy

Previously QoS multicast frames had the Normal Acknowledgment QoS
control bits set. This would cause broadcast frames to be discarded by
peers with which we have a BA session, since their sequence number would
fall outside the allowed range. Set No Ack QoS control bits on multicast
QoS frames and filter these in de-aggregation code.
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>

v2: Use proper QoS Ack Policy ctl field mask (Christian)

v3: Clean up conditional (Johannes)
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/ieee80211.h

@@ -128,6 +128,7 @@
 #define IEEE80211_QOS_CTL_ACK_POLICY_NOACK	0x0020
 #define IEEE80211_QOS_CTL_ACK_POLICY_NO_EXPL	0x0040
 #define IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK	0x0060
+#define IEEE80211_QOS_CTL_ACK_POLICY_MASK	0x0060
 /* A-MSDU 802.11n */
 #define IEEE80211_QOS_CTL_A_MSDU_PRESENT	0x0080
 /* Mesh Control 802.11s */

net/mac80211/rx.c

@@ -747,7 +747,7 @@ static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
 	struct sta_info *sta = rx->sta;
 	struct tid_ampdu_rx *tid_agg_rx;
 	u16 sc;
-	int tid;
+	u8 tid, ack_policy;
 
 	if (!ieee80211_is_data_qos(hdr->frame_control))
 		goto dont_reorder;
@@ -760,6 +760,8 @@ static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
 	if (!sta)
 		goto dont_reorder;
 
+	ack_policy = *ieee80211_get_qos_ctl(hdr) &
+		     IEEE80211_QOS_CTL_ACK_POLICY_MASK;
 	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 
 	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
@@ -770,6 +772,11 @@ static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
 	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
 		goto dont_reorder;
 
+	/* not part of a BA session */
+	if (ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK &&
+	    ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_NORMAL)
+		goto dont_reorder;
+
 	/* new, potentially un-ordered, ampdu frame - process it */
 
 	/* reset session timer */

net/mac80211/wme.c

@@ -150,7 +150,8 @@ void ieee80211_set_qos_hdr(struct ieee80211_sub_if_data *sdata,
 		/* preserve EOSP bit */
 		ack_policy = *p & IEEE80211_QOS_CTL_EOSP;
 
-		if (unlikely(sdata->local->wifi_wme_noack_test))
+		if (unlikely(sdata->local->wifi_wme_noack_test) ||
+		    is_multicast_ether_addr(hdr->addr1))
 			ack_policy |= IEEE80211_QOS_CTL_ACK_POLICY_NOACK;
 		/* qos header is 2 bytes */
 		*p++ = ack_policy | tid;