[systemd-devel] udev breaks hostap linkage of raw/user interfaces, causing wpa_supplicant problems

[David Herrmann]

Hi

On Mon, Mar 16, 2015 at 1:04 PM, Thomas Richter <thor at math.tu-berlin.de> wrote:
> Am 16.03.2015 um 12:53 schrieb David Herrmann:
>
>> I don't see how we can fix that via name_assign_type. Sure, we could
>> set this to NET_NAME_PREDICTABLE and udev would no longer rename it.
>> But the name is *NOT* predictable, so it would be a hack.
>>
>> The other fix would be to tell udev to never rename hostap devices as
>> they will break. However, that's just due to wpa_supplicant relying on
>> matching names.
>>
>> I'd prefer if we could tell wpa_supplicant to find the wlanX <->wifiY
>> relation via /sys, instead of relying on the matching names.
>>
>
> FYI, I also reported this on the wpa_supplicant mailing list, but
> there's no reaction on this yet. Apparently, it tries to "rfkill" the
> seemingly dead wifiX radio, and fails if the radio isn't where it is
> expected - or so it seems.

I wrote a patch that fixes the kernel hostap driver to report the
correct name-assign-type:
https://gist.github.com/dvdhrm/0a04ef4ad07ecfe7443e

I will wrap it up and submit it upstream.

However, it would be nice if you could describe your issues in more
detail. In particular, I cannot see any "wifiX" to "wlanX" issue. The
hostap driver exports a "wlanX" device as a base and multiple
sub-devices with a special suffix if requested by user-space.
Therefore, your system should have a "wlanX" device, and a "wlanXap" /
"wlanXsta" device, and maybe multiple "wlanXwdsY" devices. Can you
list the devices you see (with renaming enabled, if possible) so I can
figure out what exactly goes wrong?

I cannot see why you'd have a "wifiX" device. Even the wpa_supplicant
driver_hostap.c file uses "wlanXap", not "wifiX". Can you elaborate on
that, please?

Thanks
David