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Date: Tue, 12 Aug 2025 13:17:43 +0200
From: Florian Westphal <fw@strlen.de>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Antonio Ojea <antonio.ojea.garcia@gmail.com>, netfilter@vger.kernel.org
Subject: Re: Query on nftables DNAT for localhost-to-localhost traffic in
 IPv6 or without route_localnet
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References: <CABhP=tbrKeaQCAnKHbJoWNcgTthvmAEPEOcvux_W8eztR5QT1Q@mail.gmail.com>
 <aJBugbUKvPaiZ_PD@strlen.de>
 <aJpNme8xRUbhNs4P@calendula>
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Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> >This seems to do the trick:
> 
> To simplify this example below, would it be possible to extend nft_fib
> to attach DST_METADATA in prerouting to modify the ip6_route_input_lookup()
> behaviour? This is similar to the conntrack template, but for routing.

skb_valid_dst() doesn't consider DST_METADATA as a valid dst, afaics the
dst is then discarded and we end up in the same code paths.

But I think we could extend nft_fib to attach a route/dst.

But at this time I don't want to spend time on enabling such hacks
(lo-to-remote-dst-nat) unless there is a good use case for it.