mac80211: simplify association HT parameters

Instead of passing around the entire HT information
IE, extract only the HT parameters field and disable
HT if the HT information IE isn't present and well-
formed.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ieee80211_i.h

@@ -399,7 +399,6 @@ struct ieee80211_mgd_auth_data {
 struct ieee80211_mgd_assoc_data {
 	struct cfg80211_bss *bss;
 	const u8 *supp_rates;
-	const u8 *ht_operation_ie;
 
 	unsigned long timeout;
 	int tries;
@@ -414,6 +413,8 @@ struct ieee80211_mgd_assoc_data {
 	bool sent_assoc;
 	bool synced;
 
+	u8 ap_ht_param;
+
 	size_t ie_len;
 	u8 ie[];
 };

net/mac80211/mlme.c

@@ -258,12 +258,11 @@ static int ieee80211_compatible_rates(const u8 *supp_rates, int supp_rates_len,
 }
 
 static void ieee80211_add_ht_ie(struct ieee80211_sub_if_data *sdata,
-				struct sk_buff *skb, const u8 *ht_oper_ie,
+				struct sk_buff *skb, u8 ap_ht_param,
 				struct ieee80211_supported_band *sband,
 				struct ieee80211_channel *channel,
 				enum ieee80211_smps_mode smps)
 {
-	struct ieee80211_ht_operation *ht_oper;
 	u8 *pos;
 	u32 flags = channel->flags;
 	u16 cap;
@@ -271,21 +270,13 @@ static void ieee80211_add_ht_ie(struct ieee80211_sub_if_data *sdata,
 
 	BUILD_BUG_ON(sizeof(ht_cap) != sizeof(sband->ht_cap));
 
-	if (!ht_oper_ie)
-		return;
-
-	if (ht_oper_ie[1] < sizeof(struct ieee80211_ht_operation))
-		return;
-
 	memcpy(&ht_cap, &sband->ht_cap, sizeof(ht_cap));
 	ieee80211_apply_htcap_overrides(sdata, &ht_cap);
 
-	ht_oper = (struct ieee80211_ht_operation *)(ht_oper_ie + 2);
-
 	/* determine capability flags */
 	cap = ht_cap.cap;
 
-	switch (ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
+	switch (ap_ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
 	case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
 		if (flags & IEEE80211_CHAN_NO_HT40PLUS) {
 			cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
@@ -509,7 +500,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 	}
 
 	if (!(ifmgd->flags & IEEE80211_STA_DISABLE_11N))
-		ieee80211_add_ht_ie(sdata, skb, assoc_data->ht_operation_ie,
+		ieee80211_add_ht_ie(sdata, skb, assoc_data->ap_ht_param,
 				    sband, local->oper_channel, ifmgd->ap_smps);
 
 	/* if present, add any custom non-vendor IEs that go after HT */
@@ -3260,7 +3251,7 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
 	struct ieee80211_bss *bss = (void *)req->bss->priv;
 	struct ieee80211_mgd_assoc_data *assoc_data;
 	struct ieee80211_supported_band *sband;
-	const u8 *ssidie;
+	const u8 *ssidie, *ht_ie;
 	int i, err;
 
 	ssidie = ieee80211_bss_get_ie(req->bss, WLAN_EID_SSID);
@@ -3347,8 +3338,13 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
 			  (local->hw.queues >= IEEE80211_NUM_ACS);
 	assoc_data->supp_rates = bss->supp_rates;
 	assoc_data->supp_rates_len = bss->supp_rates_len;
-	assoc_data->ht_operation_ie =
-		ieee80211_bss_get_ie(req->bss, WLAN_EID_HT_OPERATION);
+
+	ht_ie = ieee80211_bss_get_ie(req->bss, WLAN_EID_HT_OPERATION);
+	if (ht_ie && ht_ie[1] >= sizeof(struct ieee80211_ht_operation))
+		assoc_data->ap_ht_param =
+			((struct ieee80211_ht_operation *)(ht_ie + 2))->ht_param;
+	else
+		ifmgd->flags |= IEEE80211_STA_DISABLE_11N;
 
 	if (bss->wmm_used && bss->uapsd_supported &&
 	    (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_UAPSD)) {