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From: "Luis R. Rodriguez" <mcgrof@gmail.com>
Date: Tue, 8 Dec 2009 10:50:30 -0800
Message-ID: <43e72e890912081050w265bcbc1sd1380ef52fc0799b@mail.gmail.com>
Subject: Re: wireless device and udev
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: "John W. Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org, linux-hotplug@vger.kernel.org
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On Tue, Dec 8, 2009 at 10:43 AM, Stephen Hemminger
<shemminger@vyatta.com> wrote:
> On Tue, 8 Dec 2009 09:29:40 -0500
> "John W. Linville" <linville@tuxdriver.com> wrote:
>
>> On Mon, Dec 07, 2009 at 05:26:16PM -0800, Stephen Hemminger wrote:
>> > The default udev persistent network rules based on hardware mac id doesn't
>> > work well when multiple SSID's are created on an access-point.  The command
>> >  iw phy phy0 interface add wlan1 type managed
>> >
>> > is supposed to make a device name wlan1, but udev sees that it has the same
>> > mac address as wlan0 and gets confused leaving the device named wlan1_rename
>> >
>> > It looks like wlanX is breaking assumptions of existing udev persistent network
>> > device name generation rules.  Perhaps there needs to be special case for wlanX
>> > devices?
>>
>> Yes, probably so.  But what would it be?  Factoring-in SSID is clearly
>> not right for the usual case (i.e. one interface on a mobile device).
>> I'm not sure what else one could use as a key.
>>
>> What does udev do for bridge, bond, or vlan devices?  Don't those
>> share MAC addresses with the underlying physical device?
>>
>> John
>
> At least on ubuntu/debian the name whitelist is:
>
>
> # device name whitelist
> KERNEL!="eth*|ath*|wlan*[0-9]|msh*|ra*|sta*|ctc*|lcs*|hsi*", GOTO="persistent_net_generator_end"
>
> So bond or bridge don't match and don't get tampered with.
>
> The problem is that wlan* device names are used for both hardware and virtual
> devices.  Udev scripts can be fixed "do the right thing" but there is not sufficient
> information for the script to decide how to attach persistent name.
> What values from sysfs (ie attributes) should script be using?  This probably
> means that additional attributes needed to be added to wireless device infrastructure
> in kernel.

We could likely use the new SET_NETDEV_DEVTYPE() but I have yet to see
where this is exported. It must be there somewhere.

  Luis