mac80211: set HT channel before association

Changing the channel type during operation is
confusing to some drivers and will be hard to
handle in multi-channel scenarios. Instead of
changing the channel, set it to the right HT
channel before authenticating/associating and
don't change it -- just update the 20/40 MHz
restrictions in rate control as needed when
changed by the AP.

This also fixes a problem that Paul missed in
his fix for the "regulatory makes us deaf"
issue -- when we couldn't use 40 MHz we still
associated saying we were using 40 MHz, which
could in similarly broken APs make us never
even connect successfully.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Documentation/networking/mac80211-auth-assoc-deauth.txt

@@ -23,7 +23,7 @@ BA session stop & deauth/disassoc frames
 end note
 end
 
-mac80211->driver: config(channel, non-HT)
+mac80211->driver: config(channel, channel type)
 mac80211->driver: bss_info_changed(set BSSID, basic rate bitmap)
 mac80211->driver: sta_state(AP, exists)
 
@@ -51,7 +51,7 @@ note over mac80211,driver: cleanup like for authenticate
 end
 
 alt not previously authenticated (FT)
-mac80211->driver: config(channel, non-HT)
+mac80211->driver: config(channel, channel type)
 mac80211->driver: bss_info_changed(set BSSID, basic rate bitmap)
 mac80211->driver: sta_state(AP, exists)
 mac80211->driver: sta_state(AP, authenticated)
@@ -67,10 +67,6 @@ end
 
 mac80211->driver: set up QoS parameters
 
-alt is HT channel
-mac80211->driver: config(channel, HT params)
-end
-
 mac80211->driver: bss_info_changed(QoS, HT, associated with AID)
 mac80211->userspace: associated
 
@@ -95,5 +91,5 @@ mac80211->driver: sta_state(AP,exists)
 mac80211->driver: sta_state(AP,not-exists)
 mac80211->driver: turn off powersave
 mac80211->driver: bss_info_changed(clear BSSID, not associated, no QoS, ...)
-mac80211->driver: config(non-HT channel type)
+mac80211->driver: config(channel type to non-HT)
 mac80211->userspace: disconnected

net/mac80211/ht.c

@@ -19,15 +19,6 @@
 #include "ieee80211_i.h"
 #include "rate.h"
 
-bool ieee80111_cfg_override_disables_ht40(struct ieee80211_sub_if_data *sdata)
-{
-	const __le16 flg = cpu_to_le16(IEEE80211_HT_CAP_SUP_WIDTH_20_40);
-	if ((sdata->u.mgd.ht_capa_mask.cap_info & flg) &&
-	    !(sdata->u.mgd.ht_capa.cap_info & flg))
-		return true;
-	return false;
-}
-
 static void __check_htcap_disable(struct ieee80211_sub_if_data *sdata,
 				  struct ieee80211_sta_ht_cap *ht_cap,
 				  u16 flag)

net/mac80211/ieee80211_i.h

@@ -379,6 +379,7 @@ enum ieee80211_sta_flags {
 	IEEE80211_STA_UAPSD_ENABLED	= BIT(7),
 	IEEE80211_STA_NULLFUNC_ACKED	= BIT(8),
 	IEEE80211_STA_RESET_SIGNAL_AVE	= BIT(9),
+	IEEE80211_STA_DISABLE_40MHZ	= BIT(10),
 };
 
 struct ieee80211_mgd_auth_data {
@@ -511,6 +512,8 @@ struct ieee80211_if_managed {
 	int rssi_min_thold, rssi_max_thold;
 	int last_ave_beacon_signal;
 
+	enum nl80211_channel_type tx_chantype;
+
 	struct ieee80211_ht_cap ht_capa; /* configured ht-cap over-rides */
 	struct ieee80211_ht_cap ht_capa_mask; /* Valid parts of ht_capa */
 };
@@ -667,12 +670,6 @@ struct ieee80211_sub_if_data {
 
 	char name[IFNAMSIZ];
 
-	/*
-	 * keep track of whether the HT opmode (stored in
-	 * vif.bss_info.ht_operation_mode) is valid.
-	 */
-	bool ht_opmode_valid;
-
 	/* to detect idle changes */
 	bool old_idle;
 
@@ -1300,7 +1297,6 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
 				       struct net_device *dev);
 
 /* HT */
-bool ieee80111_cfg_override_disables_ht40(struct ieee80211_sub_if_data *sdata);
 void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
 				     struct ieee80211_sta_ht_cap *ht_cap);
 void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_sub_if_data *sdata,