Subject: Re: [PATCH 2/5] xfrm: Pass UDP encapsulation in TX packet offload

From: Leon Romanovsky <[email-masked]>
Date: Tue, 12 Mar 2024 13:15:28 +0200

On Tue, Mar 12, 2024 at 07:20:06AM +0100, Steffen Klassert wrote:
> On Mon, Mar 11, 2024 at 05:25:03PM +0100, Paolo Abeni wrote:
> > Hi,
> > 
> > On Wed, 2024-03-06 at 11:04 +0100, Steffen Klassert wrote:
> > > From: Leon Romanovsky <[email-masked]>
> > > 
> > > In addition to citied commit in Fixes line, allow UDP encapsulation in
> > > TX path too.
> > > 
> > > Fixes: 89edf40220be ("xfrm: Support UDP encapsulation in packet offload mode")
> > > CC: Steffen Klassert <[email-masked]>
> > > Reported-by: Mike Yu <[email-masked]>
> > > Signed-off-by: Leon Romanovsky <[email-masked]>
> > > Signed-off-by: Saeed Mahameed <[email-masked]>
> > > Signed-off-by: Steffen Klassert <[email-masked]>
> > 
> > This is causing self-test failures:
> > 
> > https://netdev.bots.linux.dev/flakes.html?tn-needle=pmtu-sh
> > 
> > reverting this change locally resolves the issue.
> > 
> > @Leon, @Steffen: could you please have a look?
> 
> Looks like the check for x->encap was removed unconditionally.
> I should just be removed when XFRM_DEV_OFFLOAD_PACKET is set,
> otherwise we might create a GSO packet with UPD encapsulation.
> 
> Leon?

Right, I missed IPsec SW path, that x->encap check can be removed
in packet offload because HW supports it and in crypto offload, because
there is a check in xfrm_dev_state_add() to prevent it.

What about this fix?

diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 653e51ae3964..6e3e5a09cfeb 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -407,7 +407,7 @@ 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->type_offload)
+       if (!x->type_offload || x->xso.type == XFRM_DEV_OFFLOAD_UNSPECIFIED)
                return false;

        if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET ||

Thanks