Subject: Re: [patch net-next RFC 10/12] openvswitch: add support for datapath hardware offload

From: Jamal Hadi Salim <jhs-jkUAjuhPggJWk0Htik3J/[email-masked]>
Date: Mon, 25 Aug 2014 09:53:25 -0400

On 08/24/14 22:42, John Fastabend wrote:

> In the L2 case we already have the fdb_add and fdb_del semantics that
> are being used today by NICs with embedded switches. And we have a DSA
> patch we could dig out of patchwork for those drivers.

Indeed. That is an excellent starting point of something that is proven
to work. I was hoping L3 would follow this path. For L2,
there is the mess of claiming unicast NIC addresses as part of
the fdb, but that can almost be ignored.
Caveat: fdb_XXX works well for NICs as well as different larger
ASICs - but some quark handling is going to be needed for the tinier
openwrt type devices.
For larger switches we are going to need more for L2:
Really, the bridge already covers everthing large switches
offer (Vlan filtering, bridge port setting etc). We just need
to offload that...

> So I think it makes more sense to use the explicit interface rather
> than put another shim layer in the kernel. Its simpler and more to the
> point IMO. I suspect the resulting code will be smaller and easier to
> read. I'm the squemish one in the audience here.
>

L2/3 should be left alone and go this path. My concern on excessive
NDOs was more on the flow view of the world.

cheers,
jamal

> .John