Subject: Re: [PATCH net-next,v4 00/12] add flow_rule infrastructure

From: John Fastabend <[email-masked]>
Date: Thu, 29 Nov 2018 07:47:07 -0800

On 11/28/18 6:22 PM, Pablo Neira Ayuso wrote:
> Hi,
> 
> This patchset is another iteration to introduce an in-kernel intermediate
> representation (IR) to express ACL hardware offloads [1] [2] [3].
> 

Hi,

Also wanted to add. In an earlier thread it was mentioned this could be
used for other offload rule infrastructures specifically u32 was
mentioned. I don't think this is actually possible on the flow_rule
side. This set uses basically an enum based key system where enums
such as FLOW_DISSECTOR_KEY_* identify the field in the packet. For
every field we want to match a new key is needed. But the u32 classifier
defines fields using offset/mask and a parse graph. They do not seem
compatible to me so in the end this unifies ethtool and flower only.
Did I get this right?

So would it be better to simply map ethtool onto flower vs defining
a new one? Patch 1 seems to be pretty light-weight so maybe rather
than calling it a new IR we just need some helper routines for
drivers to work with.

Probably a more detailed cover letter explaining motivation
and any future work would help (me at least) understand the direction.
I see netfilter offload was mentioned at one point so maybe that is
the motivation that makes it more clear why flower API today is
insufficient. Mostly curious at this point I see Jiri and Florian
both reviewed it already.

Thanks,
John