Re: [PATCH xfrm-next v2 4/6] xfrm: add TX datapath support for IPsec full offload mode

[Leon Romanovsky <leon@kernel.org>]

On Mon, Aug 22, 2022 at 10:04:54AM +0200, Steffen Klassert wrote:
> On Thu, Aug 18, 2022 at 04:34:54PM +0300, Leon Romanovsky wrote:
> > On Thu, Aug 18, 2022 at 12:24:51PM +0200, Steffen Klassert wrote:
> > > On Tue, Aug 16, 2022 at 11:59:25AM +0300, Leon Romanovsky wrote:
> > > > From: Leon Romanovsky <leonro@nvidia.com>
> > > > 
> > > > In IPsec full mode, the device is going to encrypt and encapsulate
> > > > packets that are associated with offloaded policy. After successful
> > > > policy lookup to indicate if packets should be offloaded or not,
> > > > the stack forwards packets to the device to do the magic.
> > > > 
> > > > Signed-off-by: Raed Salem <raeds@nvidia.com>
> > > > Signed-off-by: Huy Nguyen <huyn@nvidia.com>
> > > > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> > > > ---
> > > >  net/xfrm/xfrm_device.c | 13 +++++++++++++
> > > >  net/xfrm/xfrm_output.c | 20 ++++++++++++++++++++
> > > >  2 files changed, 33 insertions(+)
> > > > 
> > > > diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
> > > > index 1cc482e9c87d..db5ebd36f68c 100644
> > > > --- a/net/xfrm/xfrm_device.c
> > > > +++ b/net/xfrm/xfrm_device.c
> > > 
> > > > @@ -366,6 +376,9 @@ bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
> > > >  	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
> > > >  	struct net_device *dev = x->xso.dev;
> > > >  
> > > > +	if (x->xso.type == XFRM_DEV_OFFLOAD_FULL)
> > > > +		goto ok;
> > > 
> > > You skip the PMTU checks here. I've seen that you check
> > > the packet length against the device MTU in one of your
> > > mlx5 patches, but that does not help if the PMTU is below.
> > 
> > If device supports transformation of the packet, this packet
> > won't be counted as XFRM anymore. I'm not sure that we need
> > to perform XFRM specific checks.
> 
> This is not xfrm specific, it makes sure that the packet you
> want to send fits into the PMTU.

I will add.

Thanks