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Date: Fri, 8 Mar 2024 23:46:57 +0100
From: Florian Westphal <fw@strlen.de>
To: Jason Xing <kerneljasonxing@gmail.com>
Cc: Florian Westphal <fw@strlen.de>, edumazet@google.com,
	pablo@netfilter.org, kadlec@netfilter.org, kuba@kernel.org,
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	netdev@vger.kernel.org, Jason Xing <kernelxing@tencent.com>
Subject: Re: [PATCH net-next] netfilter: conntrack: avoid sending RST to
 reply out-of-window skb
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User-Agent: Mutt/1.10.1 (2018-07-13)

Jason Xing <kerneljasonxing@gmail.com> wrote:
> > connection.  Feel free to send patches that replace drop with -accept
> > where possible/where it makes sense, but I don't think the
> > TCP_CONNTRACK_SYN_SENT one can reasonably be avoided.
> 
> Oh, are you suggesting replacing NF_DROP with -NF_ACCEPT in
> nf_conntrack_dccp_packet()?

It would be more consistent with what tcp and sctp trackers are
doing, but this should not matter in practice (the packet is malformed).

> > +       case NFCT_TCP_INVALID: {
> > +               verdict = -NF_ACCEPT;
> > +               if (ct->status & IPS_NAT_MASK)
> > +                       res = NF_DROP; /* skb would miss nat transformation */
> 
> Above line, I guess, should be 'verdict = NF_DROP'?

Yes.

> Great! I think your draft patch makes sense really, which takes NAT
> into consideration.

You could submit this officially and we could give it a try and see if
anyone complains down the road.