IFF_RUNNING without carrier after reboot

IFF_RUNNING without carrier after reboot

[Marcel Holtmann]

Hi guys,

I have a really strange issue with the 2.6.28 kernel. So when I boot
that kernel and then call "ifconfig eth0 up && ifconfig" it shows eth0
with the flag RUNNING enabled. Even if no cable is plugged into that
device.

If I then actually do plug on in and wait a few seconds (until the
lights blink) and then unplug everything is perfectly fine and it
behaves form there on normal

It is really only after boot and the 2.6.27 kernel behaves as expected.
Any ideas what's wrong here. My machine is an X61 laptop with e1000e
based Ethernet card.

Regards

Marcel

Re: IFF_RUNNING without carrier after reboot

[David Miller]

From: Marcel Holtmann <marcel@holtmann.org>
Date: Sun, 14 Dec 2008 04:28:33 +0100

> I have a really strange issue with the 2.6.28 kernel. So when I boot
> that kernel and then call "ifconfig eth0 up && ifconfig" it shows eth0
> with the flag RUNNING enabled. Even if no cable is plugged into that
> device.

The RUNNING state has no connection to link presence.

It just means that the device has been brought up by a
user configuration command like the ifconfig you ran.

It really means nothing else.

Re: IFF_RUNNING without carrier after reboot

[Herbert Xu]

David Miller <davem@davemloft.net> wrote:
>
> The RUNNING state has no connection to link presence.
> 
> It just means that the device has been brought up by a
> user configuration command like the ifconfig you ran.
> 
> It really means nothing else.

Well RUNNING did use to indicate carrier state.  In fact I didn't
even know that it had changed until this email :)

This is the changeset which did it:

commit b00055aacdb172c05067612278ba27265fcd05ce
Author: Stefan Rompf <stefan@loplof.de>
Date:   Mon Mar 20 17:09:11 2006 -0800

    [NET] core: add RFC2863 operstate

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: IFF_RUNNING without carrier after reboot

[David Miller]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Mon, 15 Dec 2008 18:28:00 +1100

> David Miller <davem@davemloft.net> wrote:
> >
> > The RUNNING state has no connection to link presence.
> > 
> > It just means that the device has been brought up by a
> > user configuration command like the ifconfig you ran.
> > 
> > It really means nothing else.
> 
> Well RUNNING did use to indicate carrier state.  In fact I didn't
> even know that it had changed until this email :)
> 
> This is the changeset which did it:

Yes, it was a bug and we fixed it more than 2 years ago.
Thanks for confirming :-)

Re: IFF_RUNNING without carrier after reboot

[Lennart Sorensen]

On Sun, Dec 14, 2008 at 11:36:25PM -0800, David Miller wrote:
> From: Herbert Xu <herbert@gondor.apana.org.au>
> Date: Mon, 15 Dec 2008 18:28:00 +1100
> 
> > David Miller <davem@davemloft.net> wrote:
> > >
> > > The RUNNING state has no connection to link presence.
> > > 
> > > It just means that the device has been brought up by a
> > > user configuration command like the ifconfig you ran.
> > > 
> > > It really means nothing else.
> > 
> > Well RUNNING did use to indicate carrier state.  In fact I didn't
> > even know that it had changed until this email :)
> > 
> > This is the changeset which did it:
> 
> Yes, it was a bug and we fixed it more than 2 years ago.
> Thanks for confirming :-)

So the RUNNING flag no longer indicates link state?  Wow that's going to
break some userspace quite badly.

Isn't the UP flag what indicates opstate?

What is the correct way for userspace to detect link state on an
interface?

-- 
Len Sorensen