On Tue, 1 Jul 2014, David Miller wrote:
From: Edward Allcutt <redacted>
Date: Mon, 30 Jun 2014 16:16:02 +0100
quoted
This is explicitly described as an eventuality that hosts must deal
with by the standard (RFC 1191) since older standards specified that
those bits must be zero.
...
quoted
One example I have seen is an OpenBSD router terminating IPSec
tunnels.
Why doesn't OpenBSD implement RFC 1191?
Why do you think I know? :)
However the standard says that you should interoperate with older implementations, and I can't see any downside to doing so.
I really don't want to allow for zero values.
Why? I have had a look through all the higher level protocols and they seem to handle this fine, if they are allowed to see the signal at all. Most of them fall back to the minimum packet size, which isn't ideal but it's much better than just stalling indefinitely.
If it helps any, I've been running several production machines with this patch for just about a year now (mostly running 3.10 stable series).
--
Edward Allcutt