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Message-ID: <Yo0kRO8xPR7iET20@unreal>
Date: Tue, 24 May 2022 21:30:28 +0300
From: Leon Romanovsky <leon@...nel.org>
To: Steffen Klassert <steffen.klassert@...unet.com>
Cc: "David S . Miller" <davem@...emloft.net>,
Herbert Xu <herbert@...dor.apana.org.au>,
netdev@...r.kernel.org, Raed Salem <raeds@...dia.com>,
ipsec-devel <devel@...ux-ipsec.org>
Subject: Re: [PATCH ipsec-next 4/6] xfrm: add TX datapath support for IPsec
full offload mode
On Wed, May 18, 2022 at 09:49:14AM +0200, Steffen Klassert wrote:
> On Mon, May 16, 2022 at 08:44:58AM +0300, Leon Romanovsky wrote:
> > On Fri, May 13, 2022 at 04:56:58PM +0200, Steffen Klassert wrote:
> > > On Tue, May 10, 2022 at 01:36:55PM +0300, Leon Romanovsky wrote:
> > > > From: Leon Romanovsky <leonro@...dia.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@...dia.com>
> > > > Signed-off-by: Huy Nguyen <huyn@...dia.com>
> > > > Signed-off-by: Leon Romanovsky <leonro@...dia.com>
> > > > ---
> > > > net/xfrm/xfrm_output.c | 19 +++++++++++++++++++
> > > > 1 file changed, 19 insertions(+)
> > > >
> > > > diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
> > > > index d4935b3b9983..2599f3dbac08 100644
> > > > --- a/net/xfrm/xfrm_output.c
> > > > +++ b/net/xfrm/xfrm_output.c
> > > > @@ -718,6 +718,25 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
> > > > break;
> > > > }
> > > >
> > > > + if (x->xso.type == XFRM_DEV_OFFLOAD_FULL) {
> > > > + struct dst_entry *dst = skb_dst_pop(skb);
> > > > +
> > > > + if (!dst) {
> > > > + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
> > > > + return -EHOSTUNREACH;
> > > > + }
> > > > +
> > > > + skb_dst_set(skb, dst);
> > > > + err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
> > > > + if (unlikely(err != 1))
> > > > + return err;
> > > > +
> > > > + if (!skb_dst(skb)->xfrm)
> > > > + return dst_output(net, skb->sk, skb);
> > > > +
> > > > + return 0;
> > > > + }
> > > > +
> > >
> > > How do we know that we send the packet really to a device that
> > > supports this type of offload? For crypto offload, we check that
> > > in xfrm_dev_offload_ok() and I think something similar is required
> > > here too.
> >
> > I think that function is needed to make sure that we will have SW
> > fallback. It is not needed in full offload, anything that is not
> > supported/wrong should be dropped by HW.
>
> Yes, but only if the final output device really supports this kind
> of offload. How can we be sure that this is the case? Packets can be
> rerouted etc. We need to make sure that the outgoing device supports
> full offload, and I think this check is missing somewhere.
I think that something like this is missing (on top of the original patch):
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 2599f3dbac08..a41aef3e8903 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -726,6 +726,9 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
return -EHOSTUNREACH;
}
+ if (!xfrm_dev_offload_ok(skb, x))
+ return -EOPNOTSUPP;
+
skb_dst_set(skb, dst);
err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
if (unlikely(err != 1))
(END)
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