[PATCH] xfrm: add SA information to the offloaded packet when if_id is set

[PATCH] xfrm: add SA information to the offloaded packet when if_id is set

[Feng Wang]

From: wangfe <wangfe@google.com>

In packet offload mode, append Security Association (SA) information
to each packet, replicating the crypto offload implementation.

The XFRM_XMIT flag is set to enable packet to be returned immediately
from the validate_xmit_xfrm function, thus aligning with the existing
code path for packet offload mode.

This SA info helps HW offload match packets to their correct security
policies. The XFRM interface ID is included, which is used in setups
with multiple XFRM interfaces where source/destination addresses alone
can't pinpoint the right policy.

Enable packet offload mode on netdevsim and add code to check the XFRM
interface ID.

Signed-off-by: wangfe <wangfe@google.com>
---
v5: https://lore.kernel.org/all/20241112192249.341515-1-wangfe@google.com/
  - Add SA information only when XFRM interface ID is non-zero.
v4: https://lore.kernel.org/all/20241104233251.3387719-1-wangfe@google.com/
  - Add offload flag check and only doing check when XFRM interface
    ID is non-zero.
v3: https://lore.kernel.org/all/20240822200252.472298-1-wangfe@google.com/
  - Add XFRM interface ID checking on netdevsim in the packet offload
    mode.
v2:
  - Add why HW offload requires the SA info to the commit message
v1: https://lore.kernel.org/all/20240812182317.1962756-1-wangfe@google.com/
---
---
 drivers/net/netdevsim/ipsec.c     | 32 ++++++++++++++++++++++++++++++-
 drivers/net/netdevsim/netdevsim.h |  1 +
 net/xfrm/xfrm_output.c            | 22 +++++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/drivers/net/netdevsim/ipsec.c b/drivers/net/netdevsim/ipsec.c
index 88187dd4eb2d..fd460f456ab7 100644
--- a/drivers/net/netdevsim/ipsec.c
+++ b/drivers/net/netdevsim/ipsec.c
@@ -153,7 +153,8 @@ static int nsim_ipsec_add_sa(struct xfrm_state *xs,
 		return -EINVAL;
 	}
 
-	if (xs->xso.type != XFRM_DEV_OFFLOAD_CRYPTO) {
+	if (xs->xso.type != XFRM_DEV_OFFLOAD_CRYPTO &&
+	    xs->xso.type != XFRM_DEV_OFFLOAD_PACKET) {
 		NL_SET_ERR_MSG_MOD(extack, "Unsupported ipsec offload type");
 		return -EINVAL;
 	}
@@ -169,6 +170,7 @@ static int nsim_ipsec_add_sa(struct xfrm_state *xs,
 	memset(&sa, 0, sizeof(sa));
 	sa.used = true;
 	sa.xs = xs;
+	sa.if_id = xs->if_id;
 
 	if (sa.xs->id.proto & IPPROTO_ESP)
 		sa.crypt = xs->ealg || xs->aead;
@@ -227,10 +229,24 @@ static bool nsim_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
 	return true;
 }
 
+static int nsim_ipsec_add_policy(struct xfrm_policy *policy,
+				 struct netlink_ext_ack *extack)
+{
+	return 0;
+}
+
+static void nsim_ipsec_del_policy(struct xfrm_policy *policy)
+{
+}
+
 static const struct xfrmdev_ops nsim_xfrmdev_ops = {
 	.xdo_dev_state_add	= nsim_ipsec_add_sa,
 	.xdo_dev_state_delete	= nsim_ipsec_del_sa,
 	.xdo_dev_offload_ok	= nsim_ipsec_offload_ok,
+
+	.xdo_dev_policy_add     = nsim_ipsec_add_policy,
+	.xdo_dev_policy_delete  = nsim_ipsec_del_policy,
+
 };
 
 bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
@@ -240,6 +256,7 @@ bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
 	struct xfrm_state *xs;
 	struct nsim_sa *tsa;
 	u32 sa_idx;
+	struct xfrm_offload *xo;
 
 	/* do we even need to check this packet? */
 	if (!sp)
@@ -275,6 +292,19 @@ bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
 		return false;
 	}
 
+	if (xs->if_id) {
+		if (xs->if_id != tsa->if_id) {
+			netdev_err(ns->netdev, "unmatched if_id %d %d\n",
+				   xs->if_id, tsa->if_id);
+			return false;
+		}
+		xo = xfrm_offload(skb);
+		if (!xo || !(xo->flags & XFRM_XMIT)) {
+			netdev_err(ns->netdev, "offload flag missing or wrong\n");
+			return false;
+		}
+	}
+
 	ipsec->tx++;
 
 	return true;
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index bf02efa10956..4941b6e46d0a 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -41,6 +41,7 @@ struct nsim_sa {
 	__be32 ipaddr[4];
 	u32 key[4];
 	u32 salt;
+	u32 if_id;
 	bool used;
 	bool crypt;
 	bool rx;
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index e5722c95b8bb..59ac45f0c4ac 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -706,6 +706,8 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
 	struct xfrm_state *x = skb_dst(skb)->xfrm;
 	int family;
 	int err;
+	struct xfrm_offload *xo;
+	struct sec_path *sp;
 
 	family = (x->xso.type != XFRM_DEV_OFFLOAD_PACKET) ? x->outer_mode.family
 		: skb_dst(skb)->ops->family;
@@ -728,7 +730,27 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
 			kfree_skb(skb);
 			return -EHOSTUNREACH;
 		}
+		if (x->if_id) {
+			sp = secpath_set(skb);
+			if (!sp) {
+				XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+				kfree_skb(skb);
+				return -ENOMEM;
+			}
+
+			sp->olen++;
+			sp->xvec[sp->len++] = x;
+			xfrm_state_hold(x);
 
+			xo = xfrm_offload(skb);
+			if (!xo) {
+				secpath_reset(skb);
+				XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+				kfree_skb(skb);
+				return -EINVAL;
+			}
+			xo->flags |= XFRM_XMIT;
+		}
 		return xfrm_output_resume(sk, skb, 0);
 	}
 
-- 
2.47.0.338.g60cca15819-goog

Re: [PATCH] xfrm: add SA information to the offloaded packet when if_id is set

[Paolo Abeni]

Hi,

On 11/19/24 23:04, Feng Wang wrote:
> From: wangfe <wangfe@google.com>

Unneeded, since the author (you) matches the submitter email address
(yours).

BTW please include a patch revision number into the subj prefix to help
reviewers.

> @@ -240,6 +256,7 @@ bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
>  	struct xfrm_state *xs;
>  	struct nsim_sa *tsa;
>  	u32 sa_idx;
> +	struct xfrm_offload *xo;

This is network driver code, please respect the reverse x-mas tree order
above.

> diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
> index e5722c95b8bb..59ac45f0c4ac 100644
> --- a/net/xfrm/xfrm_output.c
> +++ b/net/xfrm/xfrm_output.c
> @@ -706,6 +706,8 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
>  	struct xfrm_state *x = skb_dst(skb)->xfrm;
>  	int family;
>  	int err;
> +	struct xfrm_offload *xo;
> +	struct sec_path *sp;

I see the xfrm subtree is more relaxed with the reverse x-mas tree
order, but for consistency I would respect it even here.

Cheers,

Paolo

Re: [PATCH] xfrm: add SA information to the offloaded packet when if_id is set

[Feng Wang]

Hi Paolo,

Thanks for your comments, I will upload a new patch to address your
comments soon.

Feng

On Thu, Nov 21, 2024 at 12:09 AM Paolo Abeni <pabeni@redhat.com> wrote:
>
> Hi,
>
> On 11/19/24 23:04, Feng Wang wrote:
> > From: wangfe <wangfe@google.com>
>
> Unneeded, since the author (you) matches the submitter email address
> (yours).
>
> BTW please include a patch revision number into the subj prefix to help
> reviewers.
>
> > @@ -240,6 +256,7 @@ bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
> >       struct xfrm_state *xs;
> >       struct nsim_sa *tsa;
> >       u32 sa_idx;
> > +     struct xfrm_offload *xo;
>
> This is network driver code, please respect the reverse x-mas tree order
> above.
>
> > diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
> > index e5722c95b8bb..59ac45f0c4ac 100644
> > --- a/net/xfrm/xfrm_output.c
> > +++ b/net/xfrm/xfrm_output.c
> > @@ -706,6 +706,8 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
> >       struct xfrm_state *x = skb_dst(skb)->xfrm;
> >       int family;
> >       int err;
> > +     struct xfrm_offload *xo;
> > +     struct sec_path *sp;
>
> I see the xfrm subtree is more relaxed with the reverse x-mas tree
> order, but for consistency I would respect it even here.
>
> Cheers,
>
> Paolo
>