netdev - Re: [PATCH net-next v1] netfilter: nfnetlink: convert kfree_skb to consume

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Message-ID: <m2ed9ecrj4.fsf@gmail.com>
Date: Mon, 03 Jun 2024 10:19:27 +0100
From: Donald Hunter <donald.hunter@...il.com>
To: Simon Horman <horms@...nel.org>
Cc: netdev@...r.kernel.org,  Jakub Kicinski <kuba@...nel.org>,  "David S.
 Miller" <davem@...emloft.net>,  Eric Dumazet <edumazet@...gle.com>,  Paolo
 Abeni <pabeni@...hat.com>,  Pablo Neira Ayuso <pablo@...filter.org>,
  Jozsef Kadlecsik <kadlec@...filter.org>,
  netfilter-devel@...r.kernel.org,  donald.hunter@...hat.com
Subject: Re: [PATCH net-next v1] netfilter: nfnetlink: convert kfree_skb to
 consume_skb

Simon Horman <horms@...nel.org> writes:

> On Tue, May 28, 2024 at 11:37:54AM +0100, Donald Hunter wrote:
>> Use consume_skb in the batch code path to avoid generating spurious
>> NOT_SPECIFIED skb drop reasons.
>> 
>> Signed-off-by: Donald Hunter <donald.hunter@...il.com>
>
> Hi Donald,
>
> I do wonder if this is the correct approach. I'm happy to stand corrected,
> but my understanding is that consume_skb() is for situations where the skb
> is no longer needed for reasons other than errors. But some of these
> call-sites do appear to be error paths of sorts.
>
> ...

Hi Simon,

They all look to be application layer errors which are either
communicated back to the client or cause a replay. My understanding is
that consume_skb() should be used here since kfree_skb() now implies a
(transport?) drop.