Re: [PATCH] Work around dhclient brokenness

Rusty Russell
2008-08-19T04:43:33Z

On Tuesday 19 August 2008 13:17:57 Chris Wedgwood wrote:
> On Tue, Aug 19, 2008 at 10:45:20AM +1000, Rusty Russell wrote:
> > For those not following closely: We already have a method for the
> > guest to accept or reject features. Our problem is that the guest
> > is already accepting the CSUM feature: but one critical userspace
> > app (dhcp-client) can't actually handle it due to a bug.
>
> Can't we just get dhcp-client client fixed upstream and let the
> distro's update in a couple of months?

Herbert has already fixed the client, but it seems upstream hasn't released
yet.

> > The proposal is to add another mechanism, whereby the host doesn't
> > advertise CSUM, but advertises a new CSUM2 feature. The driver
> > doesn't accept this by default: then guest userspace says "hey, I
> > *really can* handle CSUM". This would have to be done dby resetting
> > the device in the ethtool callback (that's how we renegotiate
> > features). And guests need a special virtio hack in their init
> > scripts.
>
> If guest can have modified scripts for virtio and what not, they can
> have a fixed dhcp-client.

They need to do both. This way if they don't, it still works, but networking
is at a penalty (no CSUM offload).

Rusty.