From: shaozhengchao <shaozhengchao@huawei.com>
To: Lorenz Bauer <oss@lmb.io>, Stanislav Fomichev <sdf@google.com>
Cc: <ast@kernel.org>, <daniel@iogearbox.net>, <bpf@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <yuehaibing@huawei.com>
Subject: Re: [PATCH v4,bpf-next] bpf: Don't redirect packets with invalid pkt_len
Date: Wed, 21 Sep 2022 16:48:13 +0800 [thread overview]
Message-ID: <c416473b-af8b-3bf6-7ede-e1198b3496f5@huawei.com> (raw)
In-Reply-To: <aec8ef40-260c-4ded-b806-d381a3075ff0@www.fastmail.com>
On 2022/9/20 22:42, Lorenz Bauer wrote:
> On Mon, 19 Sep 2022, at 11:55, shaozhengchao wrote:
>> Sorry for the delay. I'm busy testing the TC module recently. I'm very
>> sorry for the user-space breakage.
>>
>> The root cause of this problem is that eth_type_trans() is called when
>> the protocol type of the SKB is parsed. The len value of the SKB is
>> reduced to 0. If the user mode requires that the forwarding succeed, or
>> if the MAC header is added again after the MAC header is subtracted,
>> is this appropriate?
>
> We don't require forwarding to succeed with a 14 byte input buffer. We also don't look at the MAC header.
>
> I think refusing to forward 0 length packets would be OK. Not 100% certain I understood you correctly, let me know if this helps.
>
> Best
> Lorenz
Hi Lorenz
Sorry. But how does the rejection of the 0 length affect the
test case? Is the return value abnormal, send packet failure or some
others?
Zhengchao Shao
next prev parent reply other threads:[~2022-09-21 8:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-15 11:55 [PATCH v4,bpf-next] bpf: Don't redirect packets with invalid pkt_len Zhengchao Shao
2022-07-15 23:30 ` Stanislav Fomichev
2022-07-19 17:00 ` patchwork-bot+netdevbpf
2022-09-14 11:19 ` Lorenz Bauer
2022-09-17 15:46 ` Stanislav Fomichev
2022-09-19 10:55 ` shaozhengchao
2022-09-20 14:42 ` Lorenz Bauer
2022-09-21 8:48 ` shaozhengchao [this message]
2022-09-21 20:59 ` Stanislav Fomichev
2022-10-13 9:36 ` Lorenz Bauer
2022-10-13 10:44 ` shaozhengchao
2022-10-14 16:29 ` Lorenz Bauer
2022-10-14 16:55 ` sdf
2022-10-15 2:36 ` shaozhengchao
2022-11-03 21:07 ` Martin KaFai Lau
2022-11-03 21:36 ` Stanislav Fomichev
2022-11-03 22:42 ` Martin KaFai Lau
2022-11-03 22:58 ` Stanislav Fomichev
2022-11-09 21:43 ` Stanislav Fomichev
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