[PATCH] mac80211: Add 802.11h CSA support

[Sujith <Sujith.Manoharan@atheros.com>]

Move to the advertised channel on reception of
a CSA element. This is needed for 802.11h compliance.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
---
v2
--
* Add a new variable to hold the CSA channel 
* Use msecs_to_jiffies for calculating expiration time
* Add a check to drop beacons in case of a frequency mismatch

v3
--
* Add a BSSID check when handling CSA action frame

 net/mac80211/ieee80211_i.h |   11 ++++++-
 net/mac80211/iface.c       |    2 +
 net/mac80211/mlme.c        |   13 +++++++
 net/mac80211/rx.c          |   20 +++++++++++
 net/mac80211/spectmgmt.c   |   77 ++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 122 insertions(+), 1 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 117718b..d2a007a 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -259,6 +259,7 @@ struct mesh_preq_queue {
 #define IEEE80211_STA_AUTO_CHANNEL_SEL	BIT(12)
 #define IEEE80211_STA_PRIVACY_INVOKED	BIT(13)
 #define IEEE80211_STA_TKIP_WEP_USED	BIT(14)
+#define IEEE80211_STA_CSA_RECEIVED	BIT(15)
 /* flags for MLME request */
 #define IEEE80211_STA_REQ_SCAN 0
 #define IEEE80211_STA_REQ_DIRECT_PROBE 1
@@ -283,7 +284,9 @@ enum ieee80211_sta_mlme_state {
 
 struct ieee80211_if_sta {
 	struct timer_list timer;
+	struct timer_list chswitch_timer;
 	struct work_struct work;
+	struct work_struct chswitch_work;
 	u8 bssid[ETH_ALEN], prev_bssid[ETH_ALEN];
 	u8 ssid[IEEE80211_MAX_SSID_LEN];
 	enum ieee80211_sta_mlme_state state;
@@ -542,6 +545,7 @@ enum {
 enum queue_stop_reason {
 	IEEE80211_QUEUE_STOP_REASON_DRIVER,
 	IEEE80211_QUEUE_STOP_REASON_PS,
+	IEEE80211_QUEUE_STOP_REASON_CSA
 };
 
 /* maximum number of hardware queues we support. */
@@ -631,7 +635,7 @@ struct ieee80211_local {
 	unsigned long last_scan_completed;
 	struct delayed_work scan_work;
 	struct ieee80211_sub_if_data *scan_sdata;
-	struct ieee80211_channel *oper_channel, *scan_channel;
+	struct ieee80211_channel *oper_channel, *scan_channel, *csa_channel;
 	enum nl80211_channel_type oper_channel_type;
 	u8 scan_ssid[IEEE80211_MAX_SSID_LEN];
 	size_t scan_ssid_len;
@@ -964,6 +968,11 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 void ieee80211_process_measurement_req(struct ieee80211_sub_if_data *sdata,
 				       struct ieee80211_mgmt *mgmt,
 				       size_t len);
+void ieee80211_chswitch_timer(unsigned long data);
+void ieee80211_chswitch_work(struct work_struct *work);
+void ieee80211_process_chanswitch(struct ieee80211_sub_if_data *sdata,
+				  struct ieee80211_channel_sw_ie *sw_elem,
+				  struct ieee80211_bss *bss);
 
 /* utility functions/constants */
 extern void *mac80211_wiphy_privid; /* for wiphy privid */
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 2c7a87d..f927641 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -443,6 +443,7 @@ static int ieee80211_stop(struct net_device *dev)
 						WLAN_REASON_DEAUTH_LEAVING);
 
 		memset(sdata->u.sta.bssid, 0, ETH_ALEN);
+		del_timer_sync(&sdata->u.sta.chswitch_timer);
 		del_timer_sync(&sdata->u.sta.timer);
 		/*
 		 * If the timer fired while we waited for it, it will have
@@ -452,6 +453,7 @@ static int ieee80211_stop(struct net_device *dev)
 		 * it no longer is.
 		 */
 		cancel_work_sync(&sdata->u.sta.work);
+		cancel_work_sync(&sdata->u.sta.chswitch_work);
 		/*
 		 * When we get here, the interface is marked down.
 		 * Call synchronize_rcu() to wait for the RX path
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e317c6d..4d25cf9 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1645,6 +1645,13 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 	if (!bss)
 		return;
 
+	if (elems->ch_switch_elem && (elems->ch_switch_elem_len == 3) &&
+	    (memcmp(mgmt->bssid, sdata->u.sta.bssid, ETH_ALEN) == 0)) {
+		struct ieee80211_channel_sw_ie *sw_elem =
+			(struct ieee80211_channel_sw_ie *)elems->ch_switch_elem;
+		ieee80211_process_chanswitch(sdata, sw_elem, bss);
+	}
+
 	/* was just updated in ieee80211_bss_info_update */
 	beacon_timestamp = bss->timestamp;
 
@@ -1781,6 +1788,9 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	    memcmp(ifsta->bssid, mgmt->bssid, ETH_ALEN) != 0)
 		return;
 
+	if (rx_status->freq != local->hw.conf.channel->center_freq)
+		return;
+
 	ieee80211_sta_wmm_params(local, ifsta, elems.wmm_param,
 				 elems.wmm_param_len);
 
@@ -2447,8 +2457,11 @@ void ieee80211_sta_setup_sdata(struct ieee80211_sub_if_data *sdata)
 
 	ifsta = &sdata->u.sta;
 	INIT_WORK(&ifsta->work, ieee80211_sta_work);
+	INIT_WORK(&ifsta->chswitch_work, ieee80211_chswitch_work);
 	setup_timer(&ifsta->timer, ieee80211_sta_timer,
 		    (unsigned long) sdata);
+	setup_timer(&ifsta->chswitch_timer, ieee80211_chswitch_timer,
+		    (unsigned long) sdata);
 	skb_queue_head_init(&ifsta->skb_queue);
 
 	ifsta->capab = WLAN_CAPABILITY_ESS;
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 384cb3b..4b7bc3d 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1564,7 +1564,9 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 {
 	struct ieee80211_local *local = rx->local;
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(rx->dev);
+	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
 	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
+	struct ieee80211_bss *bss;
 	int len = rx->skb->len;
 
 	if (!ieee80211_is_action(mgmt->frame_control))
@@ -1613,6 +1615,24 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 				return RX_DROP_MONITOR;
 			ieee80211_process_measurement_req(sdata, mgmt, len);
 			break;
+		case WLAN_ACTION_SPCT_CHL_SWITCH:
+			if (len < (IEEE80211_MIN_ACTION_SIZE +
+				   sizeof(mgmt->u.action.u.chan_switch)))
+				return RX_DROP_MONITOR;
+
+			if (memcmp(mgmt->bssid, ifsta->bssid, ETH_ALEN) != 0)
+				return RX_DROP_MONITOR;
+
+			bss = ieee80211_rx_bss_get(local, ifsta->bssid,
+					   local->hw.conf.channel->center_freq,
+					   ifsta->ssid, ifsta->ssid_len);
+			if (!bss)
+				return RX_DROP_MONITOR;
+
+			ieee80211_process_chanswitch(sdata,
+				     &mgmt->u.action.u.chan_switch.sw_elem, bss);
+			ieee80211_rx_bss_put(local, bss);
+			break;
 		}
 		break;
 	default:
diff --git a/net/mac80211/spectmgmt.c b/net/mac80211/spectmgmt.c
index f72bad6..22ad480 100644
--- a/net/mac80211/spectmgmt.c
+++ b/net/mac80211/spectmgmt.c
@@ -84,3 +84,80 @@ void ieee80211_process_measurement_req(struct ieee80211_sub_if_data *sdata,
 			mgmt->sa, mgmt->bssid,
 			mgmt->u.action.u.measurement.dialog_token);
 }
+
+void ieee80211_chswitch_work(struct work_struct *work)
+{
+	struct ieee80211_sub_if_data *sdata =
+		container_of(work, struct ieee80211_sub_if_data, u.sta.chswitch_work);
+	struct ieee80211_bss *bss;
+	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
+
+	if (!netif_running(sdata->dev))
+		return;
+
+	bss = ieee80211_rx_bss_get(sdata->local, ifsta->bssid,
+				   sdata->local->hw.conf.channel->center_freq,
+				   ifsta->ssid, ifsta->ssid_len);
+	if (!bss)
+		goto exit;
+
+	sdata->local->oper_channel = sdata->local->csa_channel;
+	if (!ieee80211_hw_config(sdata->local, IEEE80211_CONF_CHANGE_CHANNEL))
+		bss->freq = sdata->local->oper_channel->center_freq;
+
+	ieee80211_rx_bss_put(sdata->local, bss);
+exit:
+	ifsta->flags &= ~IEEE80211_STA_CSA_RECEIVED;
+	ieee80211_wake_queues_by_reason(&sdata->local->hw,
+					IEEE80211_QUEUE_STOP_REASON_CSA);
+}
+
+void ieee80211_chswitch_timer(unsigned long data)
+{
+	struct ieee80211_sub_if_data *sdata =
+		(struct ieee80211_sub_if_data *) data;
+	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
+
+	queue_work(sdata->local->hw.workqueue, &ifsta->chswitch_work);
+}
+
+void ieee80211_process_chanswitch(struct ieee80211_sub_if_data *sdata,
+				  struct ieee80211_channel_sw_ie *sw_elem,
+				  struct ieee80211_bss *bss)
+{
+	struct ieee80211_channel *new_ch;
+	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
+	int new_freq = ieee80211_channel_to_frequency(sw_elem->new_ch_num);
+
+	/* FIXME: Handle ADHOC later */
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return;
+
+	if (ifsta->state != IEEE80211_STA_MLME_ASSOCIATED)
+		return;
+
+	if (sdata->local->sw_scanning || sdata->local->hw_scanning)
+		return;
+
+	/* Disregard subsequent beacons if we are already running a timer
+	   processing a CSA */
+
+	if (ifsta->flags & IEEE80211_STA_CSA_RECEIVED)
+		return;
+
+	new_ch = ieee80211_get_channel(sdata->local->hw.wiphy, new_freq);
+	if (!new_ch || new_ch->flags & IEEE80211_CHAN_DISABLED)
+		return;
+
+	sdata->local->csa_channel = new_ch;
+
+	if (sw_elem->count <= 1) {
+		queue_work(sdata->local->hw.workqueue, &ifsta->chswitch_work);
+	} else {
+		ieee80211_stop_queues_by_reason(&sdata->local->hw,
+						IEEE80211_QUEUE_STOP_REASON_CSA);
+		ifsta->flags |= IEEE80211_STA_CSA_RECEIVED;
+		mod_timer(&ifsta->chswitch_timer,
+			  jiffies + msecs_to_jiffies(sw_elem->count * bss->beacon_int));
+	}
+}
-- 
1.6.0.3