Subject: Re: [PATCH] xfrm: Allow ESP over UDP in packet offload mode

From: Leon Romanovsky <[email-masked]>
Date: Tue, 18 Jul 2023 13:54:46 +0300

On Tue, Jul 18, 2023 at 01:15:12PM +0300, Ilia Lin wrote:
> Hi Leon,

Please don't top-post your replies.

> 
> Indeed the policy check is checking the sec_path lags set after
> decapsulation, but this has nothing to do with UDP encapsulation, the
> driver will set them anyway.

It doesn't make commit message correct.
"In packet offload mode, the RX is bypassing the XFRM, so we can enable the encapsulation."

> Regarding the driver support, each driver may restrict NAT-T support
> in their state_add callback, so in common code it may stay allowed.

We don't support out-of-tree drivers. Please submit it together with
relevant driver changes which exercise your newly opened path.

If you want, you can even take my series and submit it.

Thanks

> 
> Thanks,
> Ilia
> 
> BR,
> Ilia Lin
> 
> 
> 
> On Tue, Jul 18, 2023 at 12:53 PM Leon Romanovsky <[email-masked]> wrote:
> >
> > On Tue, Jul 18, 2023 at 12:24:05PM +0300, Ilia Lin wrote:
> > > The ESP encapsulation is not supported only in crypto mode.
> > > In packet offload mode, the RX is bypassing the XFRM,
> > > so we can enable the encapsulation.
> >
> > It is not accurate. RX is bypassed after XFRM validated packet to ensure
> > that it was really handled by HW.
> >
> > However, this patch should come with relevant driver code which should
> > support ESP over UDP. You can see it here:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git/log/?h=xfrm-next
> >  xfrm: Support UDP encapsulation in packet offload mode
> >  net/mlx5e: Support IPsec NAT-T functionality
> >  net/mlx5e: Check for IPsec NAT-T support
> >  net/mlx5: Add relevant capabilities bits to support NAT-T
> >
> > Thanks
> >
> > >
> > > Signed-off-by: Ilia Lin <[email-masked]>
> > > ---
> > >  net/xfrm/xfrm_device.c | 7 ++++---
> > >  1 file changed, 4 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
> > > index 4aff76c6f12e0..3018468d97662 100644
> > > --- a/net/xfrm/xfrm_device.c
> > > +++ b/net/xfrm/xfrm_device.c
> > > @@ -246,8 +246,10 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
> > >               return -EINVAL;
> > >       }
> > >
> > > -     /* We don't yet support UDP encapsulation and TFC padding. */
> > > -     if (x->encap || x->tfcpad) {
> > > +     is_packet_offload = xuo->flags & XFRM_OFFLOAD_PACKET;
> > > +
> > > +     /* We don't yet support UDP encapsulation except full mode and TFC padding. */
> > > +     if ((!is_packet_offload && x->encap) || x->tfcpad) {
> > >               NL_SET_ERR_MSG(extack, "Encapsulation and TFC padding can't be offloaded");
> > >               return -EINVAL;
> > >       }
> > > @@ -258,7 +260,6 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
> > >               return -EINVAL;
> > >       }
> > >
> > > -     is_packet_offload = xuo->flags & XFRM_OFFLOAD_PACKET;
> > >       dev = dev_get_by_index(net, xuo->ifindex);
> > >       if (!dev) {
> > >               if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
> > > --
> > >
> > >
>