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Re: Non-Last Small IPv6 Fragments

Erik Kline <ek@loon.co> Thu, 10 January 2019 21:44 UTC

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Reply-To: ek@loon.co
From: Erik Kline <ek@loon.co>
Date: Thu, 10 Jan 2019 13:44:39 -0800
Message-ID: <CAAedzxqUAG=1CcQ1YL1tc35Ji6=yDga90Kq+WmjEwAkKZXYHaQ@mail.gmail.com>
Subject: Re: Non-Last Small IPv6 Fragments
To: Simon Hobson <linux@thehobsons.co.uk>
Cc: IPv6 List <ipv6@ietf.org>
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On Thu, 10 Jan 2019 at 13:39, Simon Hobson <linux@thehobsons.co.uk> wrote:
>
> Tom Herbert <tom@herbertland.com> wrote:
>
> > That might be reasonable, however requiring intermediate fragments to
> > be at least 1280 MTU in IPv6 also solves that without needing to
> > define some aritrary new limit.
>
> In setting a minimum payload size for a fragment, is there a risk of conflicting with some known, or future unknown, link type with a small MTU ?

Technically that link wouldn't meet the 1280 min mtu requirement for
IPv6, right?

Even with 1280 byte min fragment sizes, a reassembly engine still
probably needs to place some limits in practice on the resources it
will devote to reassembly.  An attacker and sent 1280-sized fragments
for an endless series of 65535-sized datagrams...

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