802.11 status and futures

[Sam Leffler]

Alexander Leidinger wrote:
> On Sat, 03 Sep 2005 16:06:34 -0700
> Sam Leffler <sam at errno.com> wrote:
> 
> 
>>As soon as it's ok to have HEAD diverge I want to bring in an entirely 
>>new framework for doing scanning.  This supports things like background 
>>scanning (scanning for ap's while associated), roaming, and enables 
>>station mode power save operation.  These changes affect all drivers so 
>>committing them won't happen until I get help in updating and testing 
>>other drivers.
> 
> 
> What kind of documentation is available? Is there an HOWTO, overview or
> bare-bone-demo-driver with explanations available or do we have to use
> the source?
> 
> The gap between ath and the other drivers is getting larger and larger.
> I wanted to add WPA support to wi a while ago, but after 30 minutes of
> looking at the source and searching for documentation I still lacked
> the big picture (I know nothing about the internals, I'm just a poor
> user of 2 wi cards). Where to start, what feature can be implemented in
> software, which one needs what kind of hardware support, what needs to
> be implemented, what's optional, ...? I'm talking about documentation
> which goes beyond what the man-pages provide currently. Documentation
> which provides examples and/or teaches about how to write a driver. Do
> we have something like this?

The source code is the the place to learn about the net80211 
functionality right now.  If that's insufficient then I respond to 
questions.  Otherwise there are many resources on the web to use in 
learning about wireless networking; the slides I referenced had many url's.

The ath driver is the best example to work from to understand how a wide 
variety of features work.  Some cards with more intelligence may require 
some tweaks at the net80211 level (e.g. to disable functionality that is 
implemented in the device).

For wi a good place to learn about what's needed for WPA is Jouni 
Malinen's hostap driver for Linux.  In general you need a way to defer 
ap selection on scan to the host, send+receive WPA information elements 
in 802.11 management frames and you need to be able to pass 
host-encrypted data.  None of these are especially difficult but for wi 
are only supported by sta firmware revs >1.6 I believe.  OTOH I 
personally believe that devoting energy to legacy parts like wi is a 
waste; people should be working on getting new devices like iwi, ipw, 
ral, etc working well.  All these devices have linux drivers from which 
you can crib.

	Sam