mac80211: allow disable FAT in specific configurations

This patch allows to disable FAT channel in specific configurations.

For example the configuration (8, +1), (primary channel 8, extension
channel 12) isn't permitted in U.S., but (8, -1), (primary channel 8,
extension channel 4) is. When FAT channel configuration is not
permitted, FAT channel should be reported as not supported in the
capabilities of the HT IE in association request. And sssociation is
performed on 20Mhz channel.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 44 insertions, 2 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 6faa7006681a..d30c11337b04 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -808,8 +808,29 @@ static void ieee80211_send_assoc(struct net_device *dev,
 
         /* wmm support is a must to HT */
         if (wmm && (ifsta->flags & IEEE80211_STA_WMM_ENABLED) &&
-            sband->ht_info.ht_supported) {
-                __le16 tmp = cpu_to_le16(sband->ht_info.cap);
+            sband->ht_info.ht_supported && bss->ht_add_ie) {
+                struct ieee80211_ht_addt_info *ht_add_info =
+                        (struct ieee80211_ht_addt_info *)bss->ht_add_ie;
+                u16 cap = sband->ht_info.cap;
+                __le16 tmp;
+                u32 flags = local->hw.conf.channel->flags;
+
+                switch (ht_add_info->ht_param & IEEE80211_HT_IE_CHA_SEC_OFFSET) {
+                case IEEE80211_HT_IE_CHA_SEC_ABOVE:
+                        if (flags & IEEE80211_CHAN_NO_FAT_ABOVE) {
+                                cap &= ~IEEE80211_HT_CAP_SUP_WIDTH;
+                                cap &= ~IEEE80211_HT_CAP_SGI_40;
+                        }
+                        break;
+                case IEEE80211_HT_IE_CHA_SEC_BELOW:
+                        if (flags & IEEE80211_CHAN_NO_FAT_BELOW) {
+                                cap &= ~IEEE80211_HT_CAP_SUP_WIDTH;
+                                cap &= ~IEEE80211_HT_CAP_SGI_40;
+                        }
+                        break;
+                }
+
+                tmp = cpu_to_le16(cap);
                 pos = skb_put(skb, sizeof(struct ieee80211_ht_cap)+2);
                 *pos++ = WLAN_EID_HT_CAPABILITY;
                 *pos++ = sizeof(struct ieee80211_ht_cap);
@@ -2264,6 +2285,7 @@ static void ieee80211_rx_bss_free(struct ieee80211_sta_bss *bss)
         kfree(bss->rsn_ie);
         kfree(bss->wmm_ie);
         kfree(bss->ht_ie);
+        kfree(bss->ht_add_ie);
         kfree(bss_mesh_id(bss));
         kfree(bss_mesh_cfg(bss));
         kfree(bss);
@@ -2640,6 +2662,26 @@ static void ieee80211_rx_bss_info(struct net_device *dev,
                 bss->ht_ie_len = 0;
         }
 
+        if (elems.ht_info_elem &&
+             (!bss->ht_add_ie ||
+             bss->ht_add_ie_len != elems.ht_info_elem_len ||
+             memcmp(bss->ht_add_ie, elems.ht_info_elem,
+                        elems.ht_info_elem_len))) {
+                kfree(bss->ht_add_ie);
+                bss->ht_add_ie =
+                        kmalloc(elems.ht_info_elem_len + 2, GFP_ATOMIC);
+                if (bss->ht_add_ie) {
+                        memcpy(bss->ht_add_ie, elems.ht_info_elem - 2,
+                                elems.ht_info_elem_len + 2);
+                        bss->ht_add_ie_len = elems.ht_info_elem_len + 2;
+                } else
+                        bss->ht_add_ie_len = 0;
+        } else if (!elems.ht_info_elem && bss->ht_add_ie) {
+                kfree(bss->ht_add_ie);
+                bss->ht_add_ie = NULL;
+                bss->ht_add_ie_len = 0;
+        }
+
         bss->beacon_int = le16_to_cpu(mgmt->u.beacon.beacon_int);
         bss->capability = le16_to_cpu(mgmt->u.beacon.capab_info);