From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <xiyou.wangcong@gmail.com>
Subject: Re: [PATCH] veth: Optionally pad packets to minimum Ethernet length
Date: Tue, 12 Dec 2017 13:11:35 -0800
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References: <1513095191-127313-1-git-send-email-eswierk@skyportsystems.com>
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Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
        Benjamin Warren <ben@skyportsystems.com>,
        Keith Holleman <holleman@skyportsystems.com>
To: Ed Swierk <eswierk@skyportsystems.com>
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On Tue, Dec 12, 2017 at 8:13 AM, Ed Swierk <eswierk@skyportsystems.com> wrote:
> Most physical Ethernet devices pad short packets to the minimum length
> of 64 bytes (including FCS) on transmit. It can be useful to simulate
> this behavior when debugging a problem that results from it (such as
> incorrect L4 checksum calculation).
>
> Padding is unnecessary for most applications so leave it off by
> default. Enable padding only when the otherwise unused IFF_AUTOMEDIA
> flag is set (e.g. by writing 0x5003 to flags in sysfs).

This doesn't make sense, why should veth hot path be punished for
such an unusual flag which it doesn't care? Also, why should we allow
setting this flag via sysfs for veth from the beginning?