Subject: Re: Hardware needs to know when EAP nego is complete
From: Johannes Berg <johannes@sipsolutions.net>
To: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Cc: linux-wireless@vger.kernel.org,
	Coelho Luciano Roth <luciano.coelho@nokia.com>
In-Reply-To: <1280142400.6475.33.camel@wimaxnb.nmp.nokia.com>
References: <1280142400.6475.33.camel@wimaxnb.nmp.nokia.com>
Content-Type: text/plain; charset="UTF-8"
Date: Mon, 26 Jul 2010 13:23:50 +0200
Message-ID: <1280143430.3693.7.camel@jlt3.sipsolutions.net>
Mime-Version: 1.0
Sender: linux-wireless-owner@vger.kernel.org

On Mon, 2010-07-26 at 14:06 +0300, Juuso Oikarinen wrote:
> Hello Johannes, hello all,
> 
> As you may know the wl1271 hardware implements WLAN-Bluetooth
> co-existence by toggling a single antenna between WLAN and Bluetooth.
> 
> To pull this off, several quirks are required, for instance WLAN must be
> forced to full-PSM so that antenna-time for BT can be made available.
> This is implemented by the wl1271 driver with the help of the mac80211.
> 
> There are lots of timing issues involved, and there is a priority
> between WLAN an BT. To ensure BT A2DP and SCO work properly, BT needs to
> have enough priority at the expense of WLAN performance. While this
> works well enough when connected, during WLAN association and especially
> during EAP negotiation the priority needs to be more on the WLAN side to
> ensure reliability.
> 
> The wl1271 driver starts association with the priority on WLAN, which
> means that BT performance is compromised. The wl1271 driver should
> change the priority to BT after association and the EAP negotiations are
> complete, to make sure BT is performing acceptably.
> 
> So, what this all boils down to is that the wl1271 driver needs to know
> when the association, including the possible EAP negotations are fully
> complete, to be able to adjust the priority.
> 
> Currently, there is no such information available to the driver. In fact
> this information is not available anywhere in the kernel level either
> (as the details of the EAP negotiation, needed keys etc are controlled
> in user-space), so the trigger would need to come from user-space.
> 
> To enable this, an operand would be needed to nl80211 to indicate
> completion of association (including the EAP negotiations.)
> Corresponding functions would then be needed on the cfg80211 ops and
> mac80211 ops.
> 
> User-space would then call the operand when association is complete. For
> open/WEP AP's the operand would be called immediately after association,
> and for WPA AP's the operand would be called once the EAP negotiations
> are complete.
> 
> 
> Thoughts? Ideas? Would this be acceptable?

I really don't like this. You _can_ figure out if a given frame is EAP
by looking at its ethertype (but don't implement WAPI then!) ... can't
you just give it priority _by frame_?

Also, it doesn't make any sense, since if you really care then you want
rekeying to also have priority...

johannes