IFF_RUNNING and SIOCGMIIPHY support

David Goodenough david.goodenough at btconnect.com
Sun Feb 29 14:40:15 EST 2004


On Sunday 29 February 2004 18:14, Jouni Malinen wrote:
> On Sun, Feb 29, 2004 at 01:01:57PM +0000, David Goodenough wrote:
> > Mii-tool does no appear to be supported by hostap, and I was wondering
> > why.  Obviously the mode makes a difference, so saying that a node in
> > master mode is connected makes little sense, but for a managed or
> > ad-hoc mode node the link speed and the presence or absence of an
> > active connection would be useful.
>
> Isn't mii-tool quite Ethernet-specific? What would be the purpose of
> using it with a wireless driver? I did not notice SIOCGMIIPHY support in
> any of the kernel tree driver for wireless devices.
>

As traditionally used yes it is, but a single command line interface that
means that in a mixed wired/wireless environment I can find out if all
my links are up would be really useful.  I was thinking of this as a 
simple human interface for diagnosing problems, where the Quagga 
interface is for automatic routing calculations.

> > Quagga seems to say that it needs IFF_RUNNING supported by an
> > interface, and I guess is doing the same thing looking to see if there
> > is an active connection.  Looking in the source code I could not see
> > any occurences of this flag, but I suppose it might have a different
> > form which I missed.
>
> IFF_RUNNING was always set when the interface was up. Anyway, I have
> been thinking of adding netif_carrier_{on,off}() calls to the driver
> based on the association state and ended up doing it now. The
> development snapshot from the CVS has now code for setting the carrier
> off when in station mode and not associated. This clears the IFF_RUNNING
> flag for user space programs and generates a linkwatch event in the
> kernel.
>
> I verified that ifconfig was showing RUNNING flag only when the card was
> associated, but I did not do more testing. Does this work with Quagga?

I will download the CVS version (normally I use the version packaged for
Debian) and try it out. 

If this works then Quagga will dynamically rework the routing table
when a link goes down.  My network is cross connected, and the wireless
nodes live in inaccessible rural locations, so a network that can reconfigure
itself automatically is just what I am looking for.

Presumably this will also feed into SNMP information so that network
monitors like OpenNMS can see that a link has died.

Thanks.

David




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