Re: [Fwd: State of the Union: Wireless]

On Friday 06 January 2006 12:38, you wrote:

Hi Michael,

quoted

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.

Nothing is wrong with that.
"brainstorming" was the most dominant word in the whole text. ;)
I just personally liked the idea of having a device node in /dev for
every existing hardware wlan card. Like we have device nodes for
other real hardware, too. It felt like a bit of a "unix way" to do
this to me. I don't say this is the way to go.
If a netlink socket is used (which is possible, for sure), we stay with
the old way of having no device node in /dev for networking devices.
That is ok. But that is really only an implementation detail (and for sure
a matter of taste).
The _real_ main point I wanted to make was to _not_ use a net_device for
the master device. What else should be used for master device, let it
be a device node or a netlink socket, is rather unimportant at
this stage.

-- 
Greetings Michael.