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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@kernel.org>
To:     Daniel Xu <dxu@dxuuu.xyz>, bpf@vger.kernel.org, ast@kernel.org,
        daniel@iogearbox.net, andrii@kernel.org, memxor@gmail.com
Cc:     Daniel Xu <dxu@dxuuu.xyz>, pablo@netfilter.org, fw@strlen.de,
        netfilter-devel@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf-next 2/3] bpf: Add support for writing to nf_conn:mark
In-Reply-To: <f850bb7e20950736d9175c61d7e0691098e06182.1660592020.git.dxu@dxuuu.xyz>
References: <cover.1660592020.git.dxu@dxuuu.xyz>
 <f850bb7e20950736d9175c61d7e0691098e06182.1660592020.git.dxu@dxuuu.xyz>
Date:   Tue, 16 Aug 2022 00:25:06 +0200
Message-ID: <871qth87r1.fsf@toke.dk>
MIME-Version: 1.0
Content-Type: text/plain
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Daniel Xu <dxu@dxuuu.xyz> writes:

> Support direct writes to nf_conn:mark from TC and XDP prog types. This
> is useful when applications want to store per-connection metadata. This
> is also particularly useful for applications that run both bpf and
> iptables/nftables because the latter can trivially access this metadata.
>
> One example use case would be if a bpf prog is responsible for advanced
> packet classification and iptables/nftables is later used for routing
> due to pre-existing/legacy code.
>
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>

Didn't we agree the last time around that all field access should be
using helper kfuncs instead of allowing direct writes to struct nf_conn?

-Toke