[CUWiN-Dev] [mattw@seattlewireless.net: [Fwd: [Roofnet-hackers] Fwd: [Madwifi-users] future directions]]

[David Young]

This e-mail (below) is making the rounds.  My own personal interpretation
is that Linux is 2-3 years behind [*] the BSDs in its generic 802.11
support, and it will remain so until Linux kernel developers get their
collective heads out of their collective asses, and pick up the 802.11
subsystem that is called 'net80211' in BSD.

Part of the "major work going on outside the madwifi CVS repository"
that Sam alludes to may be virtual AP support, which he is working on.
VAPs are pretty neat by themselves, but what I think is especially cool
is that the VAP code sets a foundation for things like OPN, MultiNet,
et cetera.

Since the net80211 code can be re-used for all kinds 802.11 cards, a
small advance in net80211 can yield improvements in N drivers, without
N-times the effort.  In the BSDs, there are several drivers under the
net80211 system:

        ADMtek
        AMD PCnetMobile
        Atheros
        Cisco/Aironet 802.11b
        Intel 802.11a/b/g
        Intel 802.11b
        Intersil Prism II / Lucent WaveLAN / Apple Airport
        Intersil Prism54
        Ralink
        Realtek
        TI ACX-100

In Linux, there are just two under net80211:

        Atheros
        Realtek

One finds that in the remaining Linux drivers, there is an astounding
amount of code duplication.  Code duplication means more defects, bigger
object size, inconsistent operation, greater maintenance difficulty,
and a tremendous duplication of programming effort.

Dave

[*] NetBSD is about a year behind FreeBSD---I haven't re-imported in
that long.  Today I spent 8+ hours merging the latest code from FreeBSD.
Work still remains.  It's going more smoothly than I expected!

----- Forwarded message from Matt Westervelt <mattw at seattlewireless.net> -----

Date: Sat, 26 Feb 2005 19:07:13 -0800
From: Matt Westervelt <mattw at seattlewireless.net>
To: David Young <dyoung at pobox.com>
Subject: [Fwd: [Roofnet-hackers] Fwd: [Madwifi-users] future directions]



Date: Sun, 20 Feb 2005 15:20:59 -0500
From: John Bicket <jbicket at amsterdam.lcs.mit.edu>
To: roofnet-hackers at amsterdam.lcs.mit.edu
Subject: [Roofnet-hackers] Fwd: [Madwifi-users] future directions


----- Forwarded message from Sam Leffler <sam at errno.com> -----

Subject: [Madwifi-users] future directions
From: Sam Leffler <sam at errno.com>
To: madwifi-users at lists.sourceforge.net
Date: Fri, 18 Feb 2005 20:48:52 -0800

Some folks may have noticed that I've been scarce. Michael Renzmann 
asked me to post something explaining what's going on so people are 
equally informed.

I started working on support for Atheros hardware ~3 years ago. My 
motivation was that I wanted to build mesh networks for community 
wireless using freely available components. At the time the only 
accessible devices were made with Prism/Intersil parts. I considered 
these too limiting (read antiquated) and so hooked up with Atheros to 
bring support for their hardware to the open source community. My work 
initially was only for BSD systems. The plan was to enlist someone in 
the Linux community to do a driver for Linux. We approached numerous 
people but were unable to locate someone so I agreed to do a driver and 
this is where madwifi came from.

Madwifi has grown in fits and starts based on my available time and 
funding (I'm self-employed). Various people and companies have 
contributed along the way and each is gratefully acknowledged. While 
Atheros has been great in providing access to materials and people, 
contrary to what many folks think a large part of the time I've spent on 
this project has been unpaid.

So where's this going? My original motivation for working on madwifi was 
to make the hardware accessible to as wide a community as possible. Past 
that I hoped to help the Linux community by bringing over the net80211 
work from the BSD world. There's been an obvious need for a 
device-independent 802.11 protocol implementation in Linux and I saw 
net80211 as an excellent starting point. Recently however it's become 
clear that the Linux kernel developers have no interest in leveraging 
this work in any way shape or form. As a result, given that I don't use 
Linux on a day-to-day basis, I have zero incentive to continue being 
involved with the madwifi project and so have backed away.

Where does this leave madwifi? Michael Renzmann has stepped up to help 
keep things moving forward. He's brought in a number of folks who look 
to be doing great work and I really appreciate this. I cannot speak for 
Atheros but I believe they have a strong commitment to insure Linux 
users have good support for their products. The bottom line is that I 
think things will improve with some new blood in the project; especially 
folks that use Linux as their main system and track the kernel 
development more closely. I will try to help the developers as my time 
permits and will assist in bringing in new hal releases.

In terms of technical direction I think it's important that for Atheros 
hardware support to be most accessible to the Linux community it work 
well with the effort going on to create a "generic 802.11 stack" (as 
they describe it). Unfortunately the existing code that's been adopted 
is far from usable with Atheros hardware and has some design decisions 
that make it painful (if not impractical) to support advanced features 
such as SuperG. Trying to switch over to this code is a significant job 
that when done will provide no tangible benefit (IMO). Further, there is 
major work going on outside the madwifi CVS repository to extend the 
functionality of the current code that will make switching to this 
generic stack a step backwards. Nonetheless I still believe that the 
right thing for the madwifi community is to have a code base that fits 
into Linux. I tried to help this happen but it didn't work out. 
Hopefully others will be able to see this through.

While I'm curtailing my involvement with madwifi I plan to continue work 
on wireless networking support in FreeBSD. I expect madwifi users will 
benefit from this work.

	Sam



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----- End forwarded message -----


----- End forwarded message -----

-- 
David Young             OJC Technologies
dyoung at ojctech.com      Urbana, IL * (217) 278-3933