Re: Missing packet fields in big endian with ath9k

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

On Apr 26, 2013, at 11:50 AM, Luis Correia <lfpcorreia () gmail com> wrote:

> I check for link type this way:
> (pcap_datalink(dev_handler) ==DLT_IEEE802_11) ,
> So i'm pretty sure its the right data link.

DLT_IEEE802_11 is the *wrong* data link if you're getting a radiotap header in your packets, as you seem to indicate 
below!  If you're getting a radiotap header, and pcap_datalink(dev_handler) == DLT_IEEE802_11, the driver for your 
network adapter is buggy - it's returning ARPHRD_IEEE80211 when it should be returning ARPHRD_IEEE80211_RADIOTAP.

> Meanwhile I've media some progress by looking at iwcap 
> (https://dev.openwrt.org/browser/trunk/package/iwcap/src/iwcap.c?rev=30747)

What happens if you try to run iwcap on that interface?

> However I still can't access the RSSI value of the packet..

If you're getting packets without a radio header (which is what DLT_IEEE802_11 would imply), there's no place to get 
the RSSI from.

If you're getting packets with a radiotap header (which is what DLT_IEEE802_11_RADIO would imply), the only way to get 
the RSSI is if the driver is violating the radiotap spec, because the only mention of RSSI at

        http://www.radiotap.org

is

        http://www.radiotap.org/suggested-fields/RSSI

and, as they say, the presence-bit value picked by OpenBSD clashes with an officially assigned value for a different 
field.

You might, however, be able to get signal and noise levels, *if* the driver supplies them (just because a given value 
*can* be supplied in a radiotap header doesn't mean that a given driver *will* supply it):

        http://www.radiotap.org/defined-fields/Antenna%20signal

        http://www.radiotap.org/defined-fields/Antenna%20noise

        http://www.radiotap.org/defined-fields/dB%20antenna%20signal

        http://www.radiotap.org/defined-fields/dB%20antenna%20noise
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