Programmatic access to 802.11 info

[Jordan Coleman]

We are currently working on an embedded application that need to  
connect to wireless networks.  The UI lets the user configure one or  
more networks, select whether to use a specific network or roam among  
a list of SSIDs, view SSID scan information etc.  We are wrapping  
wpa_supplicant and letting it handle network selection, roaming, WPA  
(as well as WEP), etc. and that seems to work well enough.  However,  
at the moment, we're having trouble getting various status information  
in a reliable and efficient manner.

Our temporary code invokes "ifconfig -v <dev> list scan" and scrapes  
its output to get scanning info (it appears to provide more and better  
info than wpa_supplicant's 'scan results' command).  Similarly, we're  
scraping "wpa_cli status" and "ifconfig <dev> list sta" for  
association and signal strength information.  At best, this seems like  
the hard way to get this info and it's darn ugly, too (polling sucks,  
but having to fork and exec ifconfig on every poll sucks even more).   
What's more, some of the information we want, such as signal quality  
("n out of 5 bars", etc.), isn't really available.  We can get RSSI  
from "ifconfig list sta", but it's not the same thing.

So can anyone suggest how to go about getting this information  
straight from the system?  The application is primarily written in  
Perl, but Perl is not a hard requirement for this portion of the  
code.  The device runs FreeBSD 7 and the wireless hardware is Atheros- 
based.  So far, I've been unsuccessful in finding helpful docs and the  
FreeBSD wireless code is big enough to make grokking it a challenge.

Thanks in advance for any help you can provide.

++Jordan