mac80211: Fix n-band association problem

There are two structures named wmm_info and wmm_param, they are used while
parsing the beacon frame. (Check the function ieee802_11_parse_elems).
Certain APs like D-link does not set the fifth bit in WMM IE.
While sending the association request to n-only ap it checks for wmm_ie.
If it is set then only ieee80211_ht_cap is sent during association request.
So n-only association fails.
And this patch fixes this problem by copying the wmm_info to wmm_ie,
which enables the "wmm" flag in iee80211_send_assoc.

Signed-off-by: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
Acked-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 6b75cb6c630..c0a5345c8a6 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2709,7 +2709,26 @@ static void ieee80211_rx_bss_info(struct net_device *dev,
                         bss->wmm_ie_len = elems.wmm_param_len + 2;
                 } else
                         bss->wmm_ie_len = 0;
-        } else if (!elems.wmm_param && bss->wmm_ie) {
+        } else if (elems.wmm_info &&
+                    (!bss->wmm_ie || bss->wmm_ie_len != elems.wmm_info_len ||
+                     memcmp(bss->wmm_ie, elems.wmm_info, elems.wmm_info_len))) {
+                 /* As for certain AP's Fifth bit is not set in WMM IE in
+                  * beacon frames.So while parsing the beacon frame the
+                  * wmm_info structure is used instead of wmm_param.
+                  * wmm_info structure was never used to set bss->wmm_ie.
+                  * This code fixes this problem by copying the WME
+                  * information from wmm_info to bss->wmm_ie and enabling
+                  * n-band association.
+                  */
+                kfree(bss->wmm_ie);
+                bss->wmm_ie = kmalloc(elems.wmm_info_len + 2, GFP_ATOMIC);
+                if (bss->wmm_ie) {
+                        memcpy(bss->wmm_ie, elems.wmm_info - 2,
+                               elems.wmm_info_len + 2);
+                        bss->wmm_ie_len = elems.wmm_info_len + 2;
+                } else
+                        bss->wmm_ie_len = 0;
+        } else if (!elems.wmm_param && !elems.wmm_info && bss->wmm_ie) {
                 kfree(bss->wmm_ie);
                 bss->wmm_ie = NULL;
                 bss->wmm_ie_len = 0;