xfrm: allow state packet offload mode

Allow users to configure xfrm states with packet offload mode.
The packet mode must be requested both for policy and state, and
such requires us to do not implement fallback.

We explicitly return an error if requested packet mode can't
be configured.

Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 19 insertions, 5 deletions

diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 3b0c1ca8d4bb..3184b2c394b6 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -229,6 +229,7 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 	struct xfrm_dev_offload *xso = &x->xso;
 	xfrm_address_t *saddr;
 	xfrm_address_t *daddr;
+	bool is_packet_offload;
 
 	if (!x->type_offload) {
 		NL_SET_ERR_MSG(extack, "Type doesn't support offload");
@@ -241,11 +242,13 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 		return -EINVAL;
 	}
 
-	if (xuo->flags & ~(XFRM_OFFLOAD_IPV6 | XFRM_OFFLOAD_INBOUND)) {
+	if (xuo->flags &
+	    ~(XFRM_OFFLOAD_IPV6 | XFRM_OFFLOAD_INBOUND | XFRM_OFFLOAD_PACKET)) {
 		NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
 		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)) {
@@ -260,7 +263,7 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 					x->props.family,
 					xfrm_smark_get(0, x));
 		if (IS_ERR(dst))
-			return 0;
+			return (is_packet_offload) ? -EINVAL : 0;
 
 		dev = dst->dev;
 
@@ -271,7 +274,7 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
 		xso->dev = NULL;
 		dev_put(dev);
-		return 0;
+		return (is_packet_offload) ? -EINVAL : 0;
 	}
 
 	if (x->props.flags & XFRM_STATE_ESN &&
@@ -291,7 +294,10 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 	else
 		xso->dir = XFRM_DEV_OFFLOAD_OUT;
 
-	xso->type = XFRM_DEV_OFFLOAD_CRYPTO;
+	if (is_packet_offload)
+		xso->type = XFRM_DEV_OFFLOAD_PACKET;
+	else
+		xso->type = XFRM_DEV_OFFLOAD_CRYPTO;
 
 	err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 	if (err) {
@@ -301,7 +307,15 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 		netdev_put(dev, &xso->dev_tracker);
 		xso->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
 
-		if (err != -EOPNOTSUPP) {
+		/* User explicitly requested packet offload mode and configured
+		 * policy in addition to the XFRM state. So be civil to users,
+		 * and return an error instead of taking fallback path.
+		 *
+		 * This WARN_ON() can be seen as a documentation for driver
+		 * authors to do not return -EOPNOTSUPP in packet offload mode.
+		 */
+		WARN_ON(err == -EOPNOTSUPP && is_packet_offload);
+		if (err != -EOPNOTSUPP || is_packet_offload) {
 			NL_SET_ERR_MSG(extack, "Device failed to offload this state");
 			return err;
 		}