[PATCH] mac80211: Fix n-band association problem

[PATCH] mac80211: Fix n-band association problem

[Reinette Chatre]

From: Abhijeet Kolekar <abhijeet.kolekar@intel.com>

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>
---

This problem is also present in 2.6.25. This patch does apply to
2.6.25-rc9 after changing the filename to be patched to ieee80211_sta.c

 net/mac80211/mlme.c |   21 ++++++++++++++++++++-
 1 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e3f2cb0..4e4b704 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2668,7 +2668,26 @@ 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;
-- 
1.5.3.4

Re: [PATCH] mac80211: Fix n-band association problem

[Johannes Berg]

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On Wed, 2008-04-16 at 14:02 -0700, Reinette Chatre wrote:
> From: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
> 
> 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>

Ack, thanks for the update.

> ---
> 
> This problem is also present in 2.6.25. This patch does apply to
> 2.6.25-rc9 after changing the filename to be patched to ieee80211_sta.c

Do we want this for -stable then?

johannes

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RE: [PATCH] mac80211: Fix n-band association problem

[Chatre, Reinette]

On , Johannes Berg  wrote:

> On Wed, 2008-04-16 at 14:02 -0700, Reinette Chatre wrote:
>> From: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
>> 
>> 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>
> 
> Ack, thanks for the update.
> 
>> ---
>> 
>> This problem is also present in 2.6.25. This patch does apply to
>> 2.6.25-rc9 after changing the filename to be patched to
>> ieee80211_sta.c 
> 
> Do we want this for -stable then?

It will be great if this can make it into 2.6.25. Users who want to use
their DLink N band APs will appreciate it. I am not sure about the
status of submissions to it though as we are cutting it pretty close.

Reinette

RE: [PATCH] mac80211: Fix n-band association problem

[Johannes Berg]

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> > Do we want this for -stable then?
> 
> It will be great if this can make it into 2.6.25. Users who want to use
> their DLink N band APs will appreciate it. I am not sure about the
> status of submissions to it though as we are cutting it pretty close.

Well, .25 is released, so -stable it is.

johannes

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