xfrm: store and rely on direction to construct offload flags

XFRM state doesn't need anything from flags except to understand
direction, so store it separately. For future patches, such change
will allow us to reuse xfrm_dev_offload for policy offload too, which
has three possible directions instead of two.
Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

include/net/xfrm.h

@@ -126,12 +126,18 @@ struct xfrm_state_walk {
 	struct xfrm_address_filter *filter;
 };
 
+enum {
+	XFRM_DEV_OFFLOAD_IN = 1,
+	XFRM_DEV_OFFLOAD_OUT,
+};
+
 struct xfrm_dev_offload {
 	struct net_device	*dev;
 	netdevice_tracker	dev_tracker;
 	struct net_device	*real_dev;
 	unsigned long		offload_handle;
 	u8			flags;
+	u8			dir : 2;
 };
 
 struct xfrm_mode {

net/xfrm/xfrm_device.c

@@ -117,7 +117,7 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur
 
 	sp = skb_sec_path(skb);
 	x = sp->xvec[sp->len - 1];
-	if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
+	if (xo->flags & XFRM_GRO || x->xso.dir == XFRM_DEV_OFFLOAD_IN)
 		return skb;
 
 	/* This skb was already validated on the upper/virtual dev */
@@ -267,10 +267,16 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 	/* Don't forward bit that is not implemented */
 	xso->flags = xuo->flags & ~XFRM_OFFLOAD_IPV6;
 
+	if (xuo->flags & XFRM_OFFLOAD_INBOUND)
+		xso->dir = XFRM_DEV_OFFLOAD_IN;
+	else
+		xso->dir = XFRM_DEV_OFFLOAD_OUT;
+
 	err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 	if (err) {
 		xso->flags = 0;
 		xso->dev = NULL;
+		xso->dir = 0;
 		xso->real_dev = NULL;
 		dev_put_track(dev, &xso->dev_tracker);
 

net/xfrm/xfrm_user.c

@@ -852,7 +852,8 @@ static int copy_user_offload(struct xfrm_dev_offload *xso, struct sk_buff *skb)
 	xuo = nla_data(attr);
 	memset(xuo, 0, sizeof(*xuo));
 	xuo->ifindex = xso->dev->ifindex;
-	xuo->flags = xso->flags;
+	if (xso->dir == XFRM_DEV_OFFLOAD_IN)
+		xuo->flags = XFRM_OFFLOAD_INBOUND;
 
 	return 0;
 }