Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210727190001.914-1-kbowman@cloudflare.com> <20210727195459.GA15181@salvia>
 <CAKxSbF0tjY7EV=OOyfND8CxSmusfghvURQYnBxMz=DoNtGrfSg@mail.gmail.com>
 <20210727211029.GA17432@salvia> <CAKxSbF1bMzTc8sTQLFZpeY5XsymL+njKaTJOCb93RT6aj2NPVw@mail.gmail.com>
 <20210727212730.GA20772@salvia> <CAKxSbF3ZLjFo2TaWATCA8L-xQOEppUOhveybgtQrma=SjVoCeg@mail.gmail.com>
 <20210727215240.GA25043@salvia>
In-Reply-To: <20210727215240.GA25043@salvia>
From:   Alex Forster <aforster@cloudflare.com>
Date:   Tue, 27 Jul 2021 17:45:09 -0500
Message-ID: <CAKxSbF1cxKOLTFNZG40HLN-gAYnYM+8dXH_04vQ8+v3KXdAq8Q@mail.gmail.com>
Subject: Re: [PATCH] netfilter: xt_NFLOG: allow 128 character log prefixes
To:     Pablo Neira Ayuso <pablo@netfilter.org>
Cc:     Kyle Bowman <kbowman@cloudflare.com>,
        kernel-team <kernel-team@cloudflare.com>,
        Jozsef Kadlecsik <kadlec@netfilter.org>,
        Florian Westphal <fw@strlen.de>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
        linux-kernel@vger.kernel.org,
        Network Development <netdev@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

> Yes, you can update iptables-nft to use nft_log instead of xt_LOG,
> that requires no kernel upgrades and it will work with older kernels.

I've always been under the impression that mixing xtables and nftables
was impossible. Forgive me, but I just want to clarify one more time:
you're saying we should be able to modify iptables-nft such that the
following rule will use xt_bpf to match a packet and then nft_log to
log it, rather than xt_log as it does today?

    iptables-nft -A test-chain -d 11.22.33.44/32 -m bpf --bytecode
"1,6 0 0 65536" -j NFLOG --nflog-prefix
"0123456789012345678901234567890123456789012345678901234567890123456789"

We had some unexplained performance loss when we were evaluating
switching to iptables-nft, but if this sort of mixing is possible then
it is certainly worth reevaluating.