Identify Beacon Frame

[Avinash Patil]

Well..from userspace application you need to register which subtype of
frames you want to receive.
This is done with netlink sockets. You can check
hostapd/wpa_supplicant sources to see how this is done.

http://w1.fi/wpa_supplicant/

I assume you are using newer kernel e.g. 3.0 onwards.
Old kernels did not support cfg80211; also your WLAN device driver
needs to support mgmt register and mgmt rx.

https://www.kernel.org/doc/htmldocs/80211/API-struct-cfg80211-ops.html


Thanks,
Avinash

On Fri, Aug 28, 2015 at 10:57 AM, Gunjan Mehta <gunjanmehta08 at gmail.com> wrote:
> Avinash,
>
> Ya m talking about the WLAN.
> can you just throw some more light on cfg802.11 handlers.
>
> On Fri, Aug 28, 2015 at 11:24 PM, Avinash Patil <avinashapatil at gmail.com>
> wrote:
>>
>> Hi Gunjan,
>>
>> Are you talking about WLAN beacon frames? If so, you can you cfg80211
>> handlers to register management frames and once frame is received
>> parse frame type/subtype to check if its beacon.
>> I dont think beacon frames are delievered to netdev.
>>
>> Thanks,
>> Avinash
>>
>> On Fri, Aug 28, 2015 at 10:51 AM, Gunjan Mehta <gunjanmehta08 at gmail.com>
>> wrote:
>> > Then how do i capture the beacon frames?
>> >
>> > On Fri, Aug 28, 2015 at 10:40 PM, Jeff Haran <Jeff.Haran at citrix.com>
>> > wrote:
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> From: kernelnewbies-bounces at kernelnewbies.org
>> >> [mailto:kernelnewbies-bounces at kernelnewbies.org] On Behalf Of Gunjan
>> >> Mehta
>> >> Sent: Friday, August 28, 2015 9:21 AM
>> >> To: kernelnewbies; netfilter-devel at vger.kernel.org
>> >> Subject: Identify Beacon Frame
>> >>
>> >>
>> >>
>> >> Hi All,
>> >>
>> >>
>> >>
>> >> I am new to kernel development. I am writing a kernel module that
>> >> captures
>> >> packet at the netfilter pre - routing hook.
>> >>
>> >>
>> >>
>> >> I only want to capture the BEACON FRAME.
>> >>
>> >>
>> >>
>> >> I have few queries:
>> >>
>> >>
>> >>
>> >> 1>When the beacon frame comes to receiving machine do the sk_buff gets
>> >> allocated?
>> >>
>> >> 2> How can i identify the beacon frame at the pre routing hook?
>> >>
>> >> 3> Beacon frame consist of a string for authentication of client with
>> >> the
>> >> server, can i use sk_buff pointers to get access to that string, if
>> >> sk_buff
>> >> is allocated?
>> >>
>> >>
>> >>
>> >> Regards
>> >>
>> >> Gunjan
>> >>
>> >>
>> >>
>> >> These beacon frames do not appear to be IP packets. If that is true, I
>> >> don’t think you are going to see them in any netfilter hooks.
>> >>
>> >>
>> >>
>> >> Jeff Haran
>> >>
>> >>
>> >
>> >
>> >
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>> >
>
>