Re: [RFC net-next 0/3] Proposal for VRF-lite

[Thomas Graf <tgraf@suug.ch>]

On 06/10/15 at 01:43pm, Shrijeet Mukherjee wrote:
> On Tue, Jun 9, 2015 at 3:15 AM, Thomas Graf <tgraf@suug.ch> wrote:
> > Do I understand this correctly that swp* represent veth pairs?
> > Why do you have distinct addresses on each peer of the pair?
> > Are the addresses in N2 and N3 considered private and NATed?
> >
> > [...]
> >
> >
> ???These are physical boxes in the picture not veth pairs or NAT's :)???

I see. So if I translate this to a virtual world with veths where
the guest facing peer is in its own netns, the host facing veth
peer would get attached to a vrf device and we should be good.

> ???Are you worried about ip rule scale ? this reduces the scale to number of
> L3 domains, which should be not that large. I do think we need to speed up
> rule lookup from the linear walk we have right now.

I definitely have more L3 domains than what a linear search can
handle.

> A generic classifier seems like a bigger hammer, but if that is the way to
> replace rules it is a worthy concept.
> 
> That said, the patches from Hannes et al, will make it such that the table
> lookup maybe from the driver directly and thus will skip past the fib rule
> lookup.

The approach from Hannes definitely works for the physical world
but is undesirable for overlays, logical or encapsulations, where
we want to avoid maintaining a net_device for every virtual network.

As I said, I think this is something that can be resolved later on
with a programmable classifier.