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Date:   Tue, 27 Dec 2022 10:22:42 -0800
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
To:     Quentin Deslandes <qde@naccy.de>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Mykola Lysenko <mykolal@fb.com>, Shuah Khan <shuah@kernel.org>,
        Dmitrii Banshchikov <me@ubique.spb.ru>,
        linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org, netdev@vger.kernel.org,
        Kernel Team <kernel-team@meta.com>, fw@strlen.de
Subject: Re: [PATCH bpf-next v3 00/16] bpfilter
Message-ID: <20221227182242.ozkc6u2lbwneoi4r@macbook-pro-6.dhcp.thefacebook.com>
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On Sat, Dec 24, 2022 at 01:03:46AM +0100, Quentin Deslandes wrote:
> 
> Due to poor hardware availability on my side, I've not been able to
> benchmark those changes. I plan to get some numbers for the next iteration.

Yeah. Performance numbers would be my main question :)

> FORWARD filter chain is now supported, however, it's attached to
> TC INGRESS along with INPUT filter chain. This is due to XDP not supporting
> multiple programs to be attached. I could generate a single program
> out of both INPUT and FORWARD chains, but that would prevent another
> BPF program to be attached to the interface anyway. If a solution
> exists to attach both those programs to XDP while allowing for other
> programs to be attached, it requires more investigation. In the meantime,
> INPUT and FORWARD filtering is supported using TC.

I think we can ignore XDP chaining for now assuming that Daniel's bpf_link-tc work
will be applicable to XDP as well, so we'll have a simple chaining
for XDP eventually.

As far as attaching to TC... I think it would be great to combine bpfilter
codegen and attach to Florian's bpf hooks exactly at netfilter.
See
https://git.breakpoint.cc/cgit/fw/nf-next.git/commit/?h=nf_hook_jit_bpf_29&id=0c1ec06503cb8a142d3ad9f760b72d94ea0091fa
With nf_hook_ingress() calling either into classic iptable or into bpf_prog_run_nf
which is either generated by Florian's optimizer of nf chains or into
bpfilter generated code would be ideal.