Hi,

On Tue, May 06, 2025 at 11:08:53PM +0200, Antonio Quartulli wrote:
> From: Antonio Quartulli <anto...@openvpn.net>
> 
> IPv6 user packets (sent over the tunnel) may be larger than
> the outgoing interface MTU after encapsulation.
> When this happens ovpn should allow the kernel to fragment
> them because they are "locally generated".
> 
> To achieve the above, we must set skb->ignore_df = 1
> so that ip6_fragment() can be made aware of this decision.
> 
> Failing to do so will result in ip6_fragment() dropping
> the packet thinking it was "routed".
> 
> Reported-by: Gert Doering <g...@greenie.muc.de>
> Signed-off-by: Antonio Quartulli <anto...@openvpn.net>

Not sure what the protocol is on this - but I can confirm that this
fixes the problems I've observed (t_client, IPv6 UDP transport,
tun mtu 1500, ping with 3000 byte packets = inside *and* outside
fragmentation needed).

Details are in https://github.com/OpenVPN/ovpn-net-next/issues/3.

so:

Tested-By: Gert Doering <g...@greenie.muc.de>
Acked-By: Gert Doering <g...@greenie.muc.de>

gert
-- 
"If was one thing all people took for granted, was conviction that if you 
 feed honest figures into a computer, honest figures come out. Never doubted 
 it myself till I met a computer with a sense of humor."
                             Robert A. Heinlein, The Moon is a Harsh Mistress

Gert Doering - Munich, Germany                             g...@greenie.muc.de

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