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Date: Thu, 6 Jun 2024 16:38:16 +0200
From: Florian Westphal <fw@strlen.de>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Florian Westphal <fw@strlen.de>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	Christoph Paasch <cpaasch@apple.com>,
	Netfilter <netfilter-devel@vger.kernel.org>,
	Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
	daniel@iogearbox.net, willemb@google.com
Subject: Re: [PATCH nf] netfilter: nf_reject: init skb->dev for reset packet
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Willem de Bruijn <willemdebruijn.kernel@gmail.com> wrote:
> > I named the copypasta as nf_skb_get_hash. If placed in sk_buff.h:
> > net_get_hash_net()?
> > skb_get_hash()?
> 
> Still passing an skb too, so skb_get_hash_net()?

Sounds good to me.

> > And if either of that exists, maybe then use
> > skb_get_hash_symmetric_net(net, skb)
> 
> If symmetric is equally good for nft, that would be preferable, as it
> avoids the extra function. But I suppose it aliases the two flow
> directions, which may be exactly what you don't want?

It would actually be fine, but the more important part is that
skb->hash is set.

For the trace id, I want a stable identifier that won't change
(e.g. when nat rewrites addresses).

This currently works because skb_get_hash computes it at most once.

skb_get_hash_symmetric_net() will be used from nft_hash.c as
__skb_get_hash_symmetric "replacement".

Pablo, you can drop this patch, I will try the 'pass net to dissector'
route.