mac80211: add support for CSA in IBSS mode

This function adds the channel switch announcement implementation for the
IBSS code. It is triggered by userspace (mac80211/cfg) or by external
channel switch announcement, which have to be adopted. Both CSAs in
beacons and action frames are supported. As for AP mode, the channel
switch is applied after some time. However in IBSS mode, the channel
switch IEs are generated in the kernel.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/cfg.c

@@ -2865,30 +2865,38 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
 	if (!ieee80211_sdata_running(sdata))
 		return;
 
-	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
-		return;
-
 	sdata->radar_required = sdata->csa_radar_required;
 	err = ieee80211_vif_change_channel(sdata, &local->csa_chandef,
 					   &changed);
 	if (WARN_ON(err < 0))
 		return;
 
-	err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon);
-	if (err < 0)
-		return;
+	ieee80211_bss_info_change_notify(sdata, changed);
 
-	changed |= err;
-	kfree(sdata->u.ap.next_beacon);
-	sdata->u.ap.next_beacon = NULL;
+	switch (sdata->vif.type) {
+	case NL80211_IFTYPE_AP:
+		err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon);
+		if (err < 0)
+			return;
+		changed |= err;
+		kfree(sdata->u.ap.next_beacon);
+		sdata->u.ap.next_beacon = NULL;
+
+		ieee80211_bss_info_change_notify(sdata, err);
+		break;
+	case NL80211_IFTYPE_ADHOC:
+		ieee80211_ibss_finish_csa(sdata);
+		break;
+	default:
+		WARN_ON(1);
+		return;
+	}
 	sdata->vif.csa_active = false;
 
 	ieee80211_wake_queues_by_reason(&sdata->local->hw,
 					IEEE80211_MAX_QUEUE_MAP,
 					IEEE80211_QUEUE_STOP_REASON_CSA);
 
-	ieee80211_bss_info_change_notify(sdata, changed);
-
 	cfg80211_ch_switch_notify(sdata->dev, &local->csa_chandef);
 }
 
@@ -2936,20 +2944,56 @@ static int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 	if (sdata->vif.csa_active)
 		return -EBUSY;
 
-	/* only handle AP for now. */
 	switch (sdata->vif.type) {
 	case NL80211_IFTYPE_AP:
+		sdata->csa_counter_offset_beacon =
+			params->counter_offset_beacon;
+		sdata->csa_counter_offset_presp = params->counter_offset_presp;
+		sdata->u.ap.next_beacon =
+			cfg80211_beacon_dup(&params->beacon_after);
+		if (!sdata->u.ap.next_beacon)
+			return -ENOMEM;
+
+		err = ieee80211_assign_beacon(sdata, &params->beacon_csa);
+		if (err < 0) {
+			kfree(sdata->u.ap.next_beacon);
+			return err;
+		}
+		break;
+	case NL80211_IFTYPE_ADHOC:
+		if (!sdata->vif.bss_conf.ibss_joined)
+			return -EINVAL;
+
+		if (params->chandef.width != sdata->u.ibss.chandef.width)
+			return -EINVAL;
+
+		switch (params->chandef.width) {
+		case NL80211_CHAN_WIDTH_40:
+			if (cfg80211_get_chandef_type(&params->chandef) !=
+			    cfg80211_get_chandef_type(&sdata->u.ibss.chandef))
+				return -EINVAL;
+		case NL80211_CHAN_WIDTH_5:
+		case NL80211_CHAN_WIDTH_10:
+		case NL80211_CHAN_WIDTH_20_NOHT:
+		case NL80211_CHAN_WIDTH_20:
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		/* changes into another band are not supported */
+		if (sdata->u.ibss.chandef.chan->band !=
+		    params->chandef.chan->band)
+			return -EINVAL;
+
+		err = ieee80211_ibss_csa_beacon(sdata, params);
+		if (err < 0)
+			return err;
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 
-	sdata->u.ap.next_beacon = cfg80211_beacon_dup(&params->beacon_after);
-	if (!sdata->u.ap.next_beacon)
-		return -ENOMEM;
-
-	sdata->csa_counter_offset_beacon = params->counter_offset_beacon;
-	sdata->csa_counter_offset_presp = params->counter_offset_presp;
 	sdata->csa_radar_required = params->radar_required;
 
 	if (params->block_tx)
@@ -2957,10 +3001,6 @@ static int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 				IEEE80211_MAX_QUEUE_MAP,
 				IEEE80211_QUEUE_STOP_REASON_CSA);
 
-	err = ieee80211_assign_beacon(sdata, &params->beacon_csa);
-	if (err < 0)
-		return err;
-
 	local->csa_chandef = params->chandef;
 	sdata->vif.csa_active = true;
 
@@ -3014,7 +3054,8 @@ static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
 			need_offchan = true;
 		if (!ieee80211_is_action(mgmt->frame_control) ||
 		    mgmt->u.action.category == WLAN_CATEGORY_PUBLIC ||
-		    mgmt->u.action.category == WLAN_CATEGORY_SELF_PROTECTED)
+		    mgmt->u.action.category == WLAN_CATEGORY_SELF_PROTECTED ||
+		    mgmt->u.action.category == WLAN_CATEGORY_SPECTRUM_MGMT)
 			break;
 		rcu_read_lock();
 		sta = sta_info_get(sdata, mgmt->da);

net/mac80211/ieee80211_i.h

@@ -486,6 +486,7 @@ struct ieee80211_if_managed {
 
 struct ieee80211_if_ibss {
 	struct timer_list timer;
+	struct work_struct csa_connection_drop_work;
 
 	unsigned long last_scan_completed;
 
@@ -1329,6 +1330,10 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata);
 void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata);
 void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 				   struct sk_buff *skb);
+int ieee80211_ibss_csa_beacon(struct ieee80211_sub_if_data *sdata,
+			      struct cfg80211_csa_settings *csa_settings);
+int ieee80211_ibss_finish_csa(struct ieee80211_sub_if_data *sdata);
+void ieee80211_ibss_stop(struct ieee80211_sub_if_data *sdata);
 
 /* mesh code */
 void ieee80211_mesh_work(struct ieee80211_sub_if_data *sdata);

net/mac80211/iface.c

@@ -766,6 +766,10 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
 	if (sdata->vif.type == NL80211_IFTYPE_STATION)
 		ieee80211_mgd_stop(sdata);
 
+	if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
+		ieee80211_ibss_stop(sdata);
+
+
 	/*
 	 * Remove all stations associated with this interface.
 	 *

net/mac80211/rx.c

@@ -2402,7 +2402,8 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 		return RX_DROP_UNUSABLE;
 
 	if (!rx->sta && mgmt->u.action.category != WLAN_CATEGORY_PUBLIC &&
-	    mgmt->u.action.category != WLAN_CATEGORY_SELF_PROTECTED)
+	    mgmt->u.action.category != WLAN_CATEGORY_SELF_PROTECTED &&
+	    mgmt->u.action.category != WLAN_CATEGORY_SPECTRUM_MGMT)
 		return RX_DROP_UNUSABLE;
 
 	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
@@ -2566,31 +2567,46 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 
 		goto queue;
 	case WLAN_CATEGORY_SPECTRUM_MGMT:
-		if (status->band != IEEE80211_BAND_5GHZ)
-			break;
-
-		if (sdata->vif.type != NL80211_IFTYPE_STATION)
-			break;
-
 		/* verify action_code is present */
 		if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 			break;
 
 		switch (mgmt->u.action.u.measurement.action_code) {
 		case WLAN_ACTION_SPCT_MSR_REQ:
+			if (status->band != IEEE80211_BAND_5GHZ)
+				break;
+
 			if (len < (IEEE80211_MIN_ACTION_SIZE +
 				   sizeof(mgmt->u.action.u.measurement)))
 				break;
+
+			if (sdata->vif.type != NL80211_IFTYPE_STATION)
+				break;
+
 			ieee80211_process_measurement_req(sdata, mgmt, len);
 			goto handled;
-		case WLAN_ACTION_SPCT_CHL_SWITCH:
-			if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		case WLAN_ACTION_SPCT_CHL_SWITCH: {
+			u8 *bssid;
+			if (len < (IEEE80211_MIN_ACTION_SIZE +
+				   sizeof(mgmt->u.action.u.chan_switch)))
 				break;
 
-			if (!ether_addr_equal(mgmt->bssid, sdata->u.mgd.bssid))
+			if (sdata->vif.type != NL80211_IFTYPE_STATION &&
+			    sdata->vif.type != NL80211_IFTYPE_ADHOC)
+				break;
+
+			if (sdata->vif.type == NL80211_IFTYPE_STATION)
+				bssid = sdata->u.mgd.bssid;
+			else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
+				bssid = sdata->u.ibss.bssid;
+			else
+				break;
+
+			if (!ether_addr_equal(mgmt->bssid, bssid))
 				break;
 
 			goto queue;
+			}
 		}
 		break;
 	case WLAN_CATEGORY_SA_QUERY:

net/mac80211/tx.c

@@ -2357,15 +2357,31 @@ static void ieee80211_update_csa(struct ieee80211_sub_if_data *sdata,
 	struct probe_resp *resp;
 	int counter_offset_beacon = sdata->csa_counter_offset_beacon;
 	int counter_offset_presp = sdata->csa_counter_offset_presp;
+	u8 *beacon_data;
+	size_t beacon_data_len;
+
+	switch (sdata->vif.type) {
+	case NL80211_IFTYPE_AP:
+		beacon_data = beacon->tail;
+		beacon_data_len = beacon->tail_len;
+		break;
+	case NL80211_IFTYPE_ADHOC:
+		beacon_data = beacon->head;
+		beacon_data_len = beacon->head_len;
+		break;
+	default:
+		return;
+	}
+	if (WARN_ON(counter_offset_beacon >= beacon_data_len))
+		return;
 
 	/* warn if the driver did not check for/react to csa completeness */
-	if (WARN_ON(((u8 *)beacon->tail)[counter_offset_beacon] == 0))
+	if (WARN_ON(beacon_data[counter_offset_beacon] == 0))
 		return;
 
-	((u8 *)beacon->tail)[counter_offset_beacon]--;
+	beacon_data[counter_offset_beacon]--;
 
-	if (sdata->vif.type == NL80211_IFTYPE_AP &&
-	    counter_offset_presp) {
+	if (sdata->vif.type == NL80211_IFTYPE_AP && counter_offset_presp) {
 		rcu_read_lock();
 		resp = rcu_dereference(sdata->u.ap.probe_resp);
 
@@ -2400,6 +2416,15 @@ bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
 			goto out;
 		beacon_data = beacon->tail;
 		beacon_data_len = beacon->tail_len;
+	} else if (vif->type == NL80211_IFTYPE_ADHOC) {
+		struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+
+		beacon = rcu_dereference(ifibss->presp);
+		if (!beacon)
+			goto out;
+
+		beacon_data = beacon->head;
+		beacon_data_len = beacon->head_len;
 	} else {
 		WARN_ON(1);
 		goto out;
@@ -2484,6 +2509,10 @@ struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
 		if (!presp)
 			goto out;
 
+		if (sdata->vif.csa_active)
+			ieee80211_update_csa(sdata, presp);
+
+
 		skb = dev_alloc_skb(local->tx_headroom + presp->head_len);
 		if (!skb)
 			goto out;