netdev - Re: [PATCH net-next 1/3] udp_tunnel: allow to turn off path mtu discovery on encap sockets

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Message-ID: <b61d3e1f-02b3-ac80-4b9a-851871f7cdaa@gmail.com>
Date:   Mon, 13 Jul 2020 07:25:13 -0600
From:   David Ahern <dsahern@...il.com>
To:     Florian Westphal <fw@...len.de>,
        Stefano Brivio <sbrivio@...hat.com>
Cc:     netdev@...r.kernel.org, aconole@...hat.com
Subject: Re: [PATCH net-next 1/3] udp_tunnel: allow to turn off path mtu
 discovery on encap sockets

On 7/13/20 2:04 AM, Florian Westphal wrote:
>> As PMTU discovery happens, we have a route exception on the lower
>> layer for the given path, and we know that VXLAN will use that path,
>> so we also know there's no point in having a higher MTU on the VXLAN
>> device, it's really the maximum packet size we can use.
> No, in the setup that prompted this series the route exception is wrong.

Why is the exception wrong and why can't the exception code be fixed to
include tunnel headers?