IFF_RUNNING and hostapd

Dave Taht dave.taht at gmail.com
Fri Oct 1 18:32:42 EDT 2010

I recently configured an openwrt system (a nanostation M) as a pure
router, not bridge, in AP mode.

Neither babeld (with link detection enabled) and radvd work
(preventing ipv6 from working entirely)

ip addr

for wlan0 shows the interface as UP, but with "NO CARRIER".

In poking through the iproute2 code, it showed that the UP bit being
set on the interface and the IFF_RUNNING bit not being set = "NO

It doesn't look like the hostapd I'm using sets the IFF_RUNNING bit, ever.

So I ask... at what point, and by what, and where should RUNNING be
setup on a AP mode, purely routed, non-bridged interface?

It seems like a good idea to leave it in the NO CARRIER state until
the first client authenticates.

(If you ask why I was not bridging the ethernet and wireless devices
together, it's because this is a set of long haul IPv6 connections.
STA and adhoc mode work fine unbridged for some reason, as does AP
bridged, which makes sense as the ethernet device is up and configured

I wrote a test proggie to set IFF_RUNNING on wlan0 manually, outside
of hostapd, it didn't work...

so perhaps the problem exists deeper in the stack than hostapd? I'm
certainly willing to hack deeper into hostapd than I have so far, but
perhaps I'm barking up the wrong tree.

Dave Täht
SKYPE: davetaht
Nicaragua Tel: (int) 505-8868-4319
US Tel: 1-239-829-5608

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