From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Ahern <dsahern@gmail.com>
Subject: Re: [PATCH v15 ] net/veth/XDP: Line-rate packet forwarding in kernel
Date: Mon, 2 Apr 2018 12:09:44 -0600
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To: John Fastabend <john.fastabend@gmail.com>,
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On 4/2/18 12:03 PM, John Fastabend wrote:
> 
> Can the above be a normal BPF helper that returns an
> ifindex? Then something roughly like this patter would
> work for all drivers with redirect support,
> 
> 
>      route_ifindex = ip_route_lookup(__daddr, ....)
>      if (!route_ifindex)
>            return do_foo()
>      return xdp_redirect(route_ifindex);
>      
> So my suggestion is,
> 
>   1. enable veth xdp (including redirect support)
>   2. add a helper to lookup route from routing table
> 
> Alternatively you can skip step (2) and encode the routing
> table in BPF directly. Maybe we need a more efficient data
> structure but that should also work.
> 

That's what I have here:

https://github.com/dsahern/linux/commit/bab42f158c0925339f7519df7fb2cde8eac33aa8

And Jesper has done some measurements showing a 400% improvement in
throughput.

I have not had time to come back to the xdp forwarding set. It needs to
handle vlan devices at a minimum before I send an RFC.