mac80211: abort CSA if beacon does not include CSA IEs

In case we receive a beacon without CSA IE while we are in
the middle of channel switch - abort the operation.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -3643,6 +3643,9 @@ enum ieee80211_reconfig_type {
  * @post_channel_switch: This is an optional callback that is called
  *	after a channel switch procedure is completed, allowing the
  *	driver to go back to a normal configuration.
+ * @abort_channel_switch: This is an optional callback that is called
+ *	when channel switch procedure was completed, allowing the
+ *	driver to go back to a normal configuration.
  *
  * @join_ibss: Join an IBSS (on an IBSS interface); this is called after all
  *	information in bss_conf is set up and the beacon can be retrieved. A
@@ -3946,6 +3949,8 @@ struct ieee80211_ops {
 
 	int (*post_channel_switch)(struct ieee80211_hw *hw,
 				   struct ieee80211_vif *vif);
+	void (*abort_channel_switch)(struct ieee80211_hw *hw,
+				     struct ieee80211_vif *vif);
 
 	int (*join_ibss)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
 	void (*leave_ibss)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);

net/mac80211/driver-ops.h

@@ -1052,6 +1052,20 @@ drv_post_channel_switch(struct ieee80211_sub_if_data *sdata)
 	return ret;
 }
 
+static inline void
+drv_abort_channel_switch(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+
+	if (!check_sdata_in_driver(sdata))
+		return;
+
+	trace_drv_abort_channel_switch(local, sdata);
+
+	if (local->ops->abort_channel_switch)
+		local->ops->abort_channel_switch(&local->hw, &sdata->vif);
+}
+
 static inline int drv_join_ibss(struct ieee80211_local *local,
 				struct ieee80211_sub_if_data *sdata)
 {

net/mac80211/mlme.c

@@ -1258,6 +1258,32 @@ static void ieee80211_chswitch_timer(struct timer_list *t)
 	ieee80211_queue_work(&sdata->local->hw, &sdata->u.mgd.chswitch_work);
 }
 
+static void
+ieee80211_sta_abort_chanswitch(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+
+	if (!local->ops->abort_channel_switch)
+		return;
+
+	mutex_lock(&local->mtx);
+
+	mutex_lock(&local->chanctx_mtx);
+	ieee80211_vif_unreserve_chanctx(sdata);
+	mutex_unlock(&local->chanctx_mtx);
+
+	if (sdata->csa_block_tx)
+		ieee80211_wake_vif_queues(local, sdata,
+					  IEEE80211_QUEUE_STOP_REASON_CSA);
+
+	sdata->csa_block_tx = false;
+	sdata->vif.csa_active = false;
+
+	mutex_unlock(&local->mtx);
+
+	drv_abort_channel_switch(sdata);
+}
+
 static void
 ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 				 u64 timestamp, u32 device_timestamp,
@@ -1282,19 +1308,24 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 	if (local->scanning)
 		return;
 
-	/* disregard subsequent announcements if we are already processing */
-	if (sdata->vif.csa_active)
-		return;
-
 	current_band = cbss->channel->band;
 	res = ieee80211_parse_ch_switch_ie(sdata, elems, current_band,
 					   ifmgd->flags,
 					   ifmgd->associated->bssid, &csa_ie);
-	if (res	< 0)
+	if (res < 0) {
 		ieee80211_queue_work(&local->hw,
 				     &ifmgd->csa_connection_drop_work);
-	if (res)
 		return;
+	}
+
+	if (res && beacon && sdata->vif.csa_active &&
+	    !ifmgd->csa_waiting_bcn) {
+		ieee80211_sta_abort_chanswitch(sdata);
+		return;
+	} else if (sdata->vif.csa_active || res) {
+		/* disregard subsequent announcements if already processing */
+		return;
+	}
 
 	if (!cfg80211_chandef_usable(local->hw.wiphy, &csa_ie.chandef,
 				     IEEE80211_CHAN_DISABLED)) {

net/mac80211/trace.h

@@ -2452,6 +2452,12 @@ DEFINE_EVENT(local_sdata_evt, drv_post_channel_switch,
 	     TP_ARGS(local, sdata)
 );
 
+DEFINE_EVENT(local_sdata_evt, drv_abort_channel_switch,
+	     TP_PROTO(struct ieee80211_local *local,
+		      struct ieee80211_sub_if_data *sdata),
+	     TP_ARGS(local, sdata)
+);
+
 TRACE_EVENT(drv_get_txpower,
 	TP_PROTO(struct ieee80211_local *local,
 		 struct ieee80211_sub_if_data *sdata,