linux-kernel - Re: forcedeth ?

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Date:	Thu, 2 Aug 2007 13:33:12 +0200
From:	"Kay Sievers" <kay.sievers@...y.org>
To:	"Carl-Daniel Hailfinger" <c-d.hailfinger.devel.2006@....net>
Cc:	"Gabriel C" <nix.or.die@...glemail.com>,
	"Sasa Ostrouska" <casaxa@...il.com>,
	"Avuton Olrich" <avuton@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: forcedeth ?

On 7/31/07, Kay Sievers <kay.sievers@...y.org> wrote:
> On 7/31/07, Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@....net> wrote:
> > On 31.07.2007 00:17, Gabriel C wrote:
> > > Sasa Ostrouska wrote:
> > >
> > >> Gabriel, hmm, shouldnt udev be able to autoconfigure that ? But I need
> > >> to check that, thx for the tip.
> > >
> > > Yes udev does this based on the MAC address but AFAIK forcedeth is 'special' for some reason
> > > ( which I can really remember now and gets on each boot a new MAC address or alike )
> >
> > Ah yes, that's a workaround for certain buggy boards to make sure you're
> > not left without networking even if the MAC address stored on the board
> > is bogus.
> >
> > Basically, forcedeth checks if the MAC address supplied by your
> > mainboard is bogus and autogenerates a random MAC address from a private
> > range (prefix 00:00:6c) as workaround. However, it will complain loudly
> > if it has to do that.
> >
> > Quoting from forcedeth.c:
> > > if (!is_valid_ether_addr(dev->perm_addr)) {
> > >       /*
> > >        * Bad mac address. At least one bios sets the mac address
> > >        * to 01:23:45:67:89:ab
> > >        */
> > >       printk(KERN_ERR "%s: Invalid Mac address detected: %02x:%02x:%02x:%02x:%02x:%02x\n",
> > >               pci_name(pci_dev),
> > >               dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
> > >               dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);
> > >       printk(KERN_ERR "Please complain to your hardware vendor. Switching to a random MAC.\n");
> > >       dev->dev_addr[0] = 0x00;
> > >       dev->dev_addr[1] = 0x00;
> > >       dev->dev_addr[2] = 0x6c;
> > >       get_random_bytes(&dev->dev_addr[3], 3);
> > > }
> >
> > Sometimes it helps to update the BIOS and/or set the MAC address which
> > is printed on the board as MAC address in the BIOS.
>
> In any case, it would be nice if the network core could add something like:
>   MAC_ORIGIN=device
>   MAC_ORIGIN=user
>   MAC_ORIGIN=random
> or whatever makes sense here, to the uevent environment. So userspace
> can handle according to that, like falling back using the
> bus-slot-number to lookup the persistent name, or whatever is
> appropriate.

Can't we use the "locally administered" bit in the MAC address? By
checking for ENV{address}=="?[2367abef]:*", we would skip the
persistent rule generation based on the MAC address?

Thanks,
Kay
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