Re: [PATCH] xfrm: Add pre-encap fragmentation for packet offload

[Steffen Klassert]

On Tue, Nov 26, 2024 at 03:21:45PM +0200, Leon Romanovsky wrote:
> On Tue, Nov 26, 2024 at 01:59:31PM +0100, Steffen Klassert wrote:
> > On Tue, Nov 26, 2024 at 10:35:13AM +0200, Leon Romanovsky wrote:
> > > 
> > > Steffen, do we need special case for packet offload here? My preference is
> > > to make sure that we will have as less possible special cases for packet
> > > offload.
> > 
> > Looks like the problem on packet offload is that packets
> > bigger than MTU size are dropped before the PMTU signaling
> > is handled.
> 
> But PMTU should be less or equal to MTU, even before first packet was
> sent. Otherwise already first packet will be fragmented.

Atually I ment PMTU. On packet offload, we just drop packets bigger
than PMTU. We need to make sure that xfrm{4,6}_tunnel_check_size
is called. This will either fragment or do PMTU signaling.