netdev - Re: [PATCH net-next 1/2] net: flow_offload: mangle 128-bit packet field with one action

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Message-ID: <20190820173344.3nrzfjboyztz3lji@salvia>
Date:   Tue, 20 Aug 2019 19:33:44 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     Edward Cree <ecree@...arflare.com>
Cc:     netfilter-devel@...r.kernel.org, davem@...emloft.net,
        netdev@...r.kernel.org, jakub.kicinski@...ronome.com,
        jiri@...nulli.us, vladbu@...lanox.com
Subject: Re: [PATCH net-next 1/2] net: flow_offload: mangle 128-bit packet
 field with one action

On Tue, Aug 20, 2019 at 05:00:26PM +0100, Edward Cree wrote:
> On 20/08/2019 15:44, Pablo Neira Ayuso wrote:
> > It looks to me this limitation is coming from tc pedit.
> >
> > Four actions to mangle an IPv6 address consume more memory when making
> > the translation, and if you expect a lot of rules.
>
> Your change means that now every pedit uses four hw entries, even if it
>  was only meant to be a 32-bit mangle.

It makes no sense to me that matching an IPv6 address takes _one_
action, while mangling an IPv6 address takes _four_ actions.

A consistent model for drivers is good to have.

I can update tc pedit to generate one single action for offset
consecutive packet editions, if that is the concern, I'll send a v2.