xfrm: Add a new lookup key to match xfrm interfaces.

This patch adds the xfrm interface id as a lookup key
for xfrm states and policies. With this we can assign
states and policies to virtual xfrm interfaces.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Shannon Nelson <shannon.nelson@oracle.com>
Acked-by: Benedict Wong <benedictwong@google.com>
Tested-by: Benedict Wong <benedictwong@google.com>
Tested-by: Antony Antony <antony@phenome.org>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 3dc83ba..e8bada4 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -147,6 +147,7 @@
 	struct xfrm_id		id;
 	struct xfrm_selector	sel;
 	struct xfrm_mark	mark;
+	u32			if_id;
 	u32			tfcpad;
 
 	u32			genid;
@@ -574,6 +575,7 @@
 	atomic_t		genid;
 	u32			priority;
 	u32			index;
+	u32			if_id;
 	struct xfrm_mark	mark;
 	struct xfrm_selector	selector;
 	struct xfrm_lifetime_cfg lft;
@@ -1533,7 +1535,7 @@
 				   struct xfrm_tmpl *tmpl,
 				   struct xfrm_policy *pol, int *err,
 				   unsigned short family);
-struct xfrm_state *xfrm_stateonly_find(struct net *net, u32 mark,
+struct xfrm_state *xfrm_stateonly_find(struct net *net, u32 mark, u32 if_id,
 				       xfrm_address_t *daddr,
 				       xfrm_address_t *saddr,
 				       unsigned short family,
@@ -1690,20 +1692,20 @@
 		     void *);
 void xfrm_policy_walk_done(struct xfrm_policy_walk *walk, struct net *net);
 int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl);
-struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark,
+struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u32 if_id,
 					  u8 type, int dir,
 					  struct xfrm_selector *sel,
 					  struct xfrm_sec_ctx *ctx, int delete,
 					  int *err);
-struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u8, int dir,
-				     u32 id, int delete, int *err);
+struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u32 if_id, u8,
+				     int dir, u32 id, int delete, int *err);
 int xfrm_policy_flush(struct net *net, u8 type, bool task_valid);
 void xfrm_policy_hash_rebuild(struct net *net);
 u32 xfrm_get_acqseq(void);
 int verify_spi_info(u8 proto, u32 min, u32 max);
 int xfrm_alloc_spi(struct xfrm_state *x, u32 minspi, u32 maxspi);
 struct xfrm_state *xfrm_find_acq(struct net *net, const struct xfrm_mark *mark,
-				 u8 mode, u32 reqid, u8 proto,
+				 u8 mode, u32 reqid, u32 if_id, u8 proto,
 				 const xfrm_address_t *daddr,
 				 const xfrm_address_t *saddr, int create,
 				 unsigned short family);
@@ -2019,6 +2021,15 @@
 	return (m->v & m->m) | (mark & ~m->m);
 }
 
+static inline int xfrm_if_id_put(struct sk_buff *skb, __u32 if_id)
+{
+	int ret = 0;
+
+	if (if_id)
+		ret = nla_put_u32(skb, XFRMA_IF_ID, if_id);
+	return ret;
+}
+
 static inline int xfrm_tunnel_check(struct sk_buff *skb, struct xfrm_state *x,
 				    unsigned int family)
 {