linux-kernel - Re: [PATCH bpf-next 0/7] Support defragmenting IPv(4|6) packets in BPF

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Message-ID: <874jmthtiu.fsf@toke.dk>
Date:   Tue, 27 Jun 2023 16:25:13 +0200
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     Daniel Xu <dxu@...uu.xyz>, bpf@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-kselftest@...r.kernel.org, coreteam@...filter.org,
        netfilter-devel@...r.kernel.org, fw@...len.de, daniel@...earbox.net
Cc:     dsahern@...nel.org
Subject: Re: [PATCH bpf-next 0/7] Support defragmenting IPv(4|6) packets in BPF

> The basic idea is we bump a refcnt on the netfilter defrag module and
> then run the bpf prog after the defrag module runs. This allows bpf
> progs to transparently see full, reassembled packets. The nice thing
> about this is that progs don't have to carry around logic to detect
> fragments.

One high-level comment after glancing through the series: Instead of
allocating a flag specifically for the defrag module, why not support
loading (and holding) arbitrary netfilter modules in the UAPI? If we
need to allocate a new flag every time someone wants to use a netfilter
module along with BPF we'll run out of flags pretty quickly :)

-Toke