Re: 802.11 + radio headers question...

[Guy Harris <guy () alum mit edu>]

On Apr 14, 2009, at 9:24 AM, David Young wrote:

> On Tue, Apr 14, 2009 at 11:54:50AM -0400, Eddie Harari wrote:
> > so when i "sniff" a packet from my "monitor" mode intel chipset  
> > based wifi
> > card ,
> > how do i know which radio info is preceding the 802.11 header ?
>
> The DLT that you have set determines the radio header.

...if you've selected one.  On some platforms (Linux and Mac OS X  
10.4), you (currently) can't choose a header using libpcap (and will  
never be able to do so on Mac OS X 10.4, as the OS doesn't support  
it); however, with libpcap 1.0 or later, if you request monitor mode  
by using pcap_create(), pcap_set_rfmon(p, 1), and pcap_activate(p),  
libpcap will attempt to get some form of radio header if it can.
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