netdev - Re: [PATCH] selftest/bpf: fix IPV6FR handling in flow dissector

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Message-ID: <87h7pvvtk9.fsf@cloudflare.com>
Date:   Thu, 12 Nov 2020 10:00:06 +0100
From:   Jakub Sitnicki <jakub@...udflare.com>
To:     Daniel Borkmann <daniel@...earbox.net>,
        Santucci Pierpaolo <santucci@...genesys.com>
Cc:     Andrii Nakryiko <andrii.nakryiko@...il.com>,
        Shuah Khan <shuah@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>, Martin Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Andrii Nakryiko <andrii@...nel.org>,
        john fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        sdf@...gle.com
Subject: Re: [PATCH] selftest/bpf: fix IPV6FR handling in flow dissector

On Thu, Nov 12, 2020 at 12:06 AM CET, Daniel Borkmann wrote:

[...]

>>> I'm not initimately familiar with this test, but looking at the change
>>> I'd consider that Destinations Options and encapsulation headers can
>>> follow the Fragment Header.
>>>
>>> With enough of Dst Opts or levels of encapsulation, transport header
>>> could be pushed to the 2nd fragment. So I'm not sure if the assertion
>>> from the IPv4 dissector that 2nd fragment and following doesn't contain
>>> any parseable header holds.
>
> Hm, staring at rfc8200, it says that the first fragment packet must include
> the upper-layer header (e.g. tcp, udp). The patch here should probably add a
> comment wrt to the rfc.

You're right, it clearly says so. Nevermind my worries about malformed
packets then. Change LGTM:

Reviewed-by: Jakub Sitnicki <jakub@...udflare.com>