[ath9k-devel] Beacon reception events at WiFi Client

[ath9k-devel] Beacon reception events at WiFi Client

[sandeep suresh]

Dear experts,
       We have a AR9287 based WiFi module on the gateway board operating in client mode. WiFi beacons are generated from the WiFi AP say every 100ms. How can we get an event at WiFi client side every time a beacon is received? At these beacon synchronization points, we want to trigger some calculations in another Linux process. Please help.
Thanks & regards
Sandeep.

[ath9k-devel] Beacon reception events at WiFi Client

[Janusz Dziedzic]

On 23 March 2016 at 16:33, sandeep suresh <sandeep.suresh@yahoo.co.in> wrote:
> Dear experts,
>        We have a AR9287 based WiFi module on the gateway board operating in client mode. WiFi beacons are generated from the WiFi AP say every 100ms. How can we get an event at WiFi client side every time a beacon is received? At these beacon synchronization points, we want to trigger some calculations in another Linux process. Please help.

It should be possible with NL80211_CMD_REGISTER_FRAME, but seems
mac80211 only supports IEEE80211_STYPE_PROBE_REQ for STA mode - so
kernel changes required here.

For quick check you can use NL80211_TEST_CMD and report such command
every beacon from mac80211 (changes in kernel required). But next you
will be sure quality of nl80211 event will be fine for you.

Other option is:
- iw wlan0 interface add mon0 type monitor
- ifconfig mon0 up
- tshark -i mon0 -Y beacon_filter_here

So, you can write simple app (similar to tshark) that will open mon0
and every beacon you are interest send signal() to another process
(but not sure about timing here, you can get beacons in packeges - eg.
5 beacons at once).

BR
Janusz

> Thanks & regards
> Sandeep.
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel

[ath9k-devel] Beacon reception events at WiFi Client

[sandeep suresh]

Dear Janusz Dziedzic,Thanks for your response. First approach is to get the information in an non-intrusive mode; that means without making changes in the linux kernel. Having said that when we use "iw" package as suggested, I have the following query. The Gateway need to be connected to any WiFi AP all the time as WiFi client. ?So as the AR9287 is running as client all the time, can it also work in monitor mode simultaneously without impacting the performance?Thanks & regards
Sandeep.

 

    On Thursday, 24 March 2016 2:41 PM, Janusz Dziedzic <janusz.dziedzic@tieto.com> wrote:
 

 On 23 March 2016 at 16:33, sandeep suresh <sandeep.suresh@yahoo.co.in> wrote:
> Dear experts,
>? ? ? ? We have a AR9287 based WiFi module on the gateway board operating in client mode. WiFi beacons are generated from the WiFi AP say every 100ms. How can we get an event at WiFi client side every time a beacon is received? At these beacon synchronization points, we want to trigger some calculations in another Linux process. Please help.

It should be possible with NL80211_CMD_REGISTER_FRAME, but seems
mac80211 only supports IEEE80211_STYPE_PROBE_REQ for STA mode - so
kernel changes required here.

For quick check you can use NL80211_TEST_CMD and report such command
every beacon from mac80211 (changes in kernel required). But next you
will be sure quality of nl80211 event will be fine for you.

Other option is:
- iw wlan0 interface add mon0 type monitor
- ifconfig mon0 up
- tshark -i mon0 -Y beacon_filter_here

So, you can write simple app (similar to tshark) that will open mon0
and every beacon you are interest send signal() to another process
(but not sure about timing here, you can get beacons in packeges - eg.
5 beacons at once).

BR
Janusz

> Thanks & regards
> Sandeep.
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel

  
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[ath9k-devel] Beacon reception events at WiFi Client

[Holger Schurig]

> How can we get an event at WiFi client side every
> time a beacon is received?

Google for monitor mode.

Many WIFI tools use this. If you need a source code example, have a look
at Kismet.