Re: [Q/RFC] BPF use in broader scope

[Eric Dumazet <eric.dumazet@gmail.com>]

On Thu, 2012-03-29 at 09:44 +0200, Jiri Pirko wrote:
> Hi all.
> 
> I came to an idea of using BPF infrastructure currently used in kernel,
> for computing hashes selecting TX ports in team device. Since the same
> data (skb) are alalyzed/used as for socket filtering, BPF seems so be quite
> suitable for this. It would allow userspace daemon to specify various
> kinds of TX selection algorithms.
> 
> Here are proposed things to be done:
> 1) introduce in-kernel api for creating sk-unattached filters (I have
>    the patch cooked up already)
> 
> 2) extend current BPF machine to allow XOR operation. Not sure if this
>    is doable or what the best of doing this is.
> 
> 3) add possibility to pass some data to the machine via
>    pre-filling "Scratch Memory Store". I think this can be done easily
>    moving "u32 mem[BPF_MEMWORDS];" to bpf_func caller and pass it as the
>    second function parameter. That should not break anything.
> 
> Then the computed hash can be either stored into Scratch memory or returned
> directly (where ordinary sk filters return len).
> 
> Does this seems reasonable? Thoughts, comments?
> 

Sure it seems good ideas.

Maybe add :

4) be able to extend skb_flow_dissect() using BPF hooks