* hostapd & mac80211: too many probe responses
@ 2011-04-01 10:37 Helmut Schaa
2011-04-01 10:46 ` Johannes Berg
0 siblings, 1 reply; 5+ messages in thread
From: Helmut Schaa @ 2011-04-01 10:37 UTC (permalink / raw)
To: linux-wireless
Hi,
I've just noticed that hostapd + mac80211 + rt2x00 produces way too many
probe responses when setup as multi bssid AP.
The reason seems to be that mac80211 receives a broadcast probe req and
drops it to the monitor interface for each vif (hence X times). And hostapd
will process each received broadcast probe req on all vifs as well (hence X
times again). Resulting in X*X probe responses instead of just X.
This can eat up quite some airtime as the probe reponses are sent at 1Mpbs.
IMO to fix this issue mac80211 should send a broadcast probe req only once
to the monitor interface. However, I don't have a good idea how to do that
right now :)
Thanks,
Helmut
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: hostapd & mac80211: too many probe responses
2011-04-01 10:37 hostapd & mac80211: too many probe responses Helmut Schaa
@ 2011-04-01 10:46 ` Johannes Berg
2011-04-01 10:55 ` Helmut Schaa
0 siblings, 1 reply; 5+ messages in thread
From: Johannes Berg @ 2011-04-01 10:46 UTC (permalink / raw)
To: Helmut Schaa; +Cc: linux-wireless
On Fri, 2011-04-01 at 12:37 +0200, Helmut Schaa wrote:
> I've just noticed that hostapd + mac80211 + rt2x00 produces way too many
> probe responses when setup as multi bssid AP.
>
> The reason seems to be that mac80211 receives a broadcast probe req and
> drops it to the monitor interface for each vif (hence X times). And hostapd
> will process each received broadcast probe req on all vifs as well (hence X
> times again). Resulting in X*X probe responses instead of just X.
>
> This can eat up quite some airtime as the probe reponses are sent at 1Mpbs.
>
> IMO to fix this issue mac80211 should send a broadcast probe req only once
> to the monitor interface. However, I don't have a good idea how to do that
> right now :)
Looks like we broke that then, IEEE80211_RX_CMNTR was intended to do
this.
johannes
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: hostapd & mac80211: too many probe responses
2011-04-01 10:46 ` Johannes Berg
@ 2011-04-01 10:55 ` Helmut Schaa
2011-04-01 11:00 ` Johannes Berg
0 siblings, 1 reply; 5+ messages in thread
From: Helmut Schaa @ 2011-04-01 10:55 UTC (permalink / raw)
To: Johannes Berg; +Cc: linux-wireless
Am Freitag, 1. April 2011 schrieb Johannes Berg:
> On Fri, 2011-04-01 at 12:37 +0200, Helmut Schaa wrote:
>
> > I've just noticed that hostapd + mac80211 + rt2x00 produces way too many
> > probe responses when setup as multi bssid AP.
> >
> > The reason seems to be that mac80211 receives a broadcast probe req and
> > drops it to the monitor interface for each vif (hence X times). And hostapd
> > will process each received broadcast probe req on all vifs as well (hence X
> > times again). Resulting in X*X probe responses instead of just X.
> >
> > This can eat up quite some airtime as the probe reponses are sent at 1Mpbs.
> >
> > IMO to fix this issue mac80211 should send a broadcast probe req only once
> > to the monitor interface. However, I don't have a good idea how to do that
> > right now :)
>
> Looks like we broke that then, IEEE80211_RX_CMNTR was intended to do
> this.
Ah, I see. I'll do some more debugging in that direction first ...
Helmut
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: hostapd & mac80211: too many probe responses
2011-04-01 10:55 ` Helmut Schaa
@ 2011-04-01 11:00 ` Johannes Berg
2011-04-01 11:39 ` Helmut Schaa
0 siblings, 1 reply; 5+ messages in thread
From: Johannes Berg @ 2011-04-01 11:00 UTC (permalink / raw)
To: Helmut Schaa; +Cc: linux-wireless
On Fri, 2011-04-01 at 12:55 +0200, Helmut Schaa wrote:
> > Looks like we broke that then, IEEE80211_RX_CMNTR was intended to do
> > this.
>
> Ah, I see. I'll do some more debugging in that direction first ...
I think the 'rx->flags = 0;' thing is just wrong.
johannes
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: hostapd & mac80211: too many probe responses
2011-04-01 11:00 ` Johannes Berg
@ 2011-04-01 11:39 ` Helmut Schaa
0 siblings, 0 replies; 5+ messages in thread
From: Helmut Schaa @ 2011-04-01 11:39 UTC (permalink / raw)
To: Johannes Berg; +Cc: linux-wireless
Am Freitag, 1. April 2011 schrieb Johannes Berg:
> On Fri, 2011-04-01 at 12:55 +0200, Helmut Schaa wrote:
>
> > > Looks like we broke that then, IEEE80211_RX_CMNTR was intended to do
> > > this.
> >
> > Ah, I see. I'll do some more debugging in that direction first ...
>
> I think the 'rx->flags = 0;' thing is just wrong.
Uhhm, yep. I'll test and send a patch.
Thanks Johannes.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-04-01 11:41 UTC | newest]
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2011-04-01 10:37 hostapd & mac80211: too many probe responses Helmut Schaa
2011-04-01 10:46 ` Johannes Berg
2011-04-01 10:55 ` Helmut Schaa
2011-04-01 11:00 ` Johannes Berg
2011-04-01 11:39 ` Helmut Schaa
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