Re: [Bcm43xx-dev] [Fwd: State of the Union: Wireless]

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