Subject: Re: [Bcm43xx-dev] [Fwd: State of the Union: Wireless]
From: Marcel Holtmann <marcel@holtmann.org>
To: Michael Buesch <mbuesch@freenet.de>
Cc: jgarzik@pobox.com, bcm43xx-dev@lists.berlios.de, netdev@vger.kernel.org,
       linux-kernel@vger.kernel.org
In-Reply-To: <200601061200.59376.mbuesch@freenet.de>
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	 <200601061200.59376.mbuesch@freenet.de>
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Date: Fri, 06 Jan 2006 12:38:14 +0100
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Hi Michael,

> How would the virtual interfaces look like? That is quite easy to answer.
> They are net_devices, as they transfer data.
> They should probaly _not_ be on top of the ethernet, as 80211 does not
> have very much in common with ethernet. Basically they share the same
> MAC address format. Does someone have another thing, which he thinks
> is shared?
> How would the master interface look like? A somewhat unusual idea came
> up. Using a device node in /dev. So every wireless card in the system
> would have a node in /dev associated (/dev/wlan0 for example).
> A node for the master device would be ok, because no data is transferred
> through it. It is only a configuration interface.
> So you would tell the, yet-to-be-written userspace tool wconfig (or something
> like that) "I need a STA in INFRA mode and want to drive it on the
> wlan0 card". So wconfig goes and write()s some data to /dev/wlan0
> telling the 80211 code to setup a virtual net_device for the driver
> associated to /dev/wlan0.
> The virtual interface is then configured though /dev/wlan0 using write()
> (no ugly ioctl anymore, you see...). Config data like TX rate,
> current essid,.... basically everything + xyz which is done by WE today,
> is written to /dev/wlan0.
> This config data is entirely cached in the 80211 code for the /dev/wlan0
> instance. This is important, to have the data persistent throughout
> suspend/resume cycles, if up/down cycles.
> After configuring, a virtual net_device (let's call it wlan0) exists,
> which can be brought up by ifconfig and data can be transferred though
> it as usual.

what is wrong with using netlink and/or sysfs for it? I don't see the
advantage of defining another /dev something interface.

Regards

Marcel


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