Beacon frame processing at user space

Jouni Malinen j at w1.fi
Sun Jan 22 10:44:23 EST 2012


On Thu, Jan 12, 2012 at 07:44:17PM +0900, ��ö wrote:
> I¡¯m working on beacon frames. IEEE Std 802.11u-2011 defines a set of IEs such as Multiple BSSID, Interworking, Advertisement Protocol, Roaming Consortium, Emergency Alert Indentifier in the beacon frame in addition to other management frames. But I found I could not register beacon frame at nl80211_mgmt_subscribe_non_ap() in drivers_nl80211.c.

You can get information from beacon frames by fetching the current scan
results (BSS table) from kernel..

> At the p2p mode of wpa_supplicant, it fails and returns ¡°Invalid Argument¡±. I tried to register beacon frame with the code below.
> 
> nl80211_register_frame(bss, bss->nl_mgmt, (WLAN_FC_TYPE_MGMT << 2) | ( WLAN_FC_STYPE_BEACON<< 4), NULL, 0) < 0)
> 
> Is this related to mode of device, such as AP, STA, GO, P2P Client?

I would expect many drivers to filter out most Beacon frames to avoid
unnecessary processing.

> To implement 802.11u, I think we need to pass beacon events and IEs to upper layers. Let me know if you have those facilities to support these beacon related things.

What part of 802.11u are you trying to implement? The scan results (BSS
table) can be used for most 802.11u needs. If you think that is not
enough for something, I would like to hear more detailed justification
on additional needs.

-- 
Jouni Malinen                                            PGP id EFC895FA


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