mac80211: send delBA on unexpected BlockAck Request

If we don't have a BA session, send delBA, as requested by the
IEEE 802.11 spec. Apply the same limit of sending such a delBA
only once as in the previous patch.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

net/mac80211/rx.c

@@ -2592,6 +2592,12 @@ ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx, struct sk_buff_head *frames)
 
 		tid = le16_to_cpu(bar_data.control) >> 12;
 
+		if (!test_bit(tid, rx->sta->ampdu_mlme.agg_session_valid) &&
+		    !test_and_set_bit(tid, rx->sta->ampdu_mlme.unexpected_agg))
+			ieee80211_send_delba(rx->sdata, rx->sta->sta.addr, tid,
+					     WLAN_BACK_RECIPIENT,
+					     WLAN_REASON_QSTA_REQUIRE_SETUP);
+
 		tid_agg_rx = rcu_dereference(rx->sta->ampdu_mlme.tid_rx[tid]);
 		if (!tid_agg_rx)
 			return RX_DROP_MONITOR;