[PATCH 1/2] cfg80211: on ibss_joined use the channel to get the proper bss object

[PATCH 1/2] cfg80211: on ibss_joined use the channel to get the proper bss object

[Antonio Quartulli]

From: Antonio Quartulli <antonio@open-mesh.com>

It may be the case that the same IBSS (same bssid and essid)
exists on two different channels (i.e. two IBSSes created
with different but fixed freq) and therefore the latter must
be also used to distinguish them.

Fix wdev->current_bss assignment by passing the channel to
cfg80211_get_bss() on ibss_joined.
This ensures that cfg80211_get_bss() picks up the proper bss
object.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
---
 net/wireless/ibss.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index 403fe29..12c878b 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -28,7 +28,7 @@ void __cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid)
 	if (!wdev->ssid_len)
 		return;
 
-	bss = cfg80211_get_bss(wdev->wiphy, NULL, bssid,
+	bss = cfg80211_get_bss(wdev->wiphy, wdev->channel, bssid,
 			       wdev->ssid, wdev->ssid_len,
 			       WLAN_CAPABILITY_IBSS, WLAN_CAPABILITY_IBSS);
 
-- 
1.8.3.2

[PATCH 2/2] mac80211: store the channel in wdev upon ibss_join

[Antonio Quartulli]

From: Antonio Quartulli <antonio@open-mesh.com>

To allow cfg80211 to use the real channel to pick up the
proper (i)bss object, store the used channel in
wdev->channel during ibss_join

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
---
 net/mac80211/ibss.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index a12afe7..2b5aa4b 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -331,6 +331,12 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 	bss = cfg80211_inform_bss_width_frame(local->hw.wiphy, chan,
 					      scan_width, mgmt,
 					      presp->head_len, 0, GFP_KERNEL);
+
+	/* store the channel so that it can be used by cfg80211 to retrieve the
+	 * correct bss object
+	 */
+	sdata->wdev.channel = chan;
+
 	cfg80211_put_bss(local->hw.wiphy, bss);
 	netif_carrier_on(sdata->dev);
 	cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
-- 
1.8.3.2

Re: [PATCH 2/2] mac80211: store the channel in wdev upon ibss_join

[Johannes Berg]

On Tue, 2013-10-15 at 00:38 +0200, Antonio Quartulli wrote:
> From: Antonio Quartulli <antonio@open-mesh.com>
> 
> To allow cfg80211 to use the real channel to pick up the
> proper (i)bss object, store the used channel in
> wdev->channel during ibss_join

WTF? No, mac80211 can't just randomly modify cfg80211-owned data.

johannes

Re: [PATCH 2/2] mac80211: store the channel in wdev upon ibss_join

[Antonio Quartulli]

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On Thu, Oct 17, 2013 at 04:36:28PM +0200, Johannes Berg wrote:
> On Tue, 2013-10-15 at 00:38 +0200, Antonio Quartulli wrote:
> > From: Antonio Quartulli <antonio@open-mesh.com>
> > 
> > To allow cfg80211 to use the real channel to pick up the
> > proper (i)bss object, store the used channel in
> > wdev->channel during ibss_join
> 
> WTF? No, mac80211 can't just randomly modify cfg80211-owned data.

Mh, ok. :)

What about setting wdev->channel in __cfg80211_join_ibss() right after having
set wdev->ssid ?
This way we leave mac80211 out and we totally handle this thing in cfg80211
only.


(I think with this change patch 1/2 makes more sense?)

-- 
Antonio Quartulli

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Re: [PATCH 2/2] mac80211: store the channel in wdev upon ibss_join

[Johannes Berg]

On Thu, 2013-10-17 at 16:48 +0200, Antonio Quartulli wrote:
> On Thu, Oct 17, 2013 at 04:36:28PM +0200, Johannes Berg wrote:
> > On Tue, 2013-10-15 at 00:38 +0200, Antonio Quartulli wrote:
> > > From: Antonio Quartulli <antonio@open-mesh.com>
> > > 
> > > To allow cfg80211 to use the real channel to pick up the
> > > proper (i)bss object, store the used channel in
> > > wdev->channel during ibss_join
> > 
> > WTF? No, mac80211 can't just randomly modify cfg80211-owned data.
> 
> Mh, ok. :)
> 
> What about setting wdev->channel in __cfg80211_join_ibss() right after having
> set wdev->ssid ?
> This way we leave mac80211 out and we totally handle this thing in cfg80211
> only.

Locking might be problematic though. I also don't know where else the
channel might be used?

johannes

Re: [PATCH 2/2] mac80211: store the channel in wdev upon ibss_join

[Antonio Quartulli]

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On Thu, Oct 17, 2013 at 04:51:28PM +0200, Johannes Berg wrote:
> On Thu, 2013-10-17 at 16:48 +0200, Antonio Quartulli wrote:
> > On Thu, Oct 17, 2013 at 04:36:28PM +0200, Johannes Berg wrote:
> > > On Tue, 2013-10-15 at 00:38 +0200, Antonio Quartulli wrote:
> > > > From: Antonio Quartulli <antonio@open-mesh.com>
> > > > 
> > > > To allow cfg80211 to use the real channel to pick up the
> > > > proper (i)bss object, store the used channel in
> > > > wdev->channel during ibss_join
> > > 
> > > WTF? No, mac80211 can't just randomly modify cfg80211-owned data.
> > 
> > Mh, ok. :)
> > 
> > What about setting wdev->channel in __cfg80211_join_ibss() right after having
> > set wdev->ssid ?
> > This way we leave mac80211 out and we totally handle this thing in cfg80211
> > only.
> 
> Locking might be problematic though. I also don't know where else the
> channel might be used?


I don't think it is used elsewhere in IBSS mode


-- 
Antonio Quartulli

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Re: [PATCH 1/2] cfg80211: on ibss_joined use the channel to get the proper bss object

[Johannes Berg]

On Tue, 2013-10-15 at 00:38 +0200, Antonio Quartulli wrote:
> From: Antonio Quartulli <antonio@open-mesh.com>
> 
> It may be the case that the same IBSS (same bssid and essid)
> exists on two different channels (i.e. two IBSSes created
> with different but fixed freq) and therefore the latter must
> be also used to distinguish them.
> 
> Fix wdev->current_bss assignment by passing the channel to
> cfg80211_get_bss() on ibss_joined.
> This ensures that cfg80211_get_bss() picks up the proper bss
> object.

This makes no sense, wdev->channel should always be NULL (unless the
same wdev was in AP or mesh mode first and that somehow leaked out?)

johannes