ipsec: add support of limited SA dump

The goal of this patch is to allow userland to dump only a part of SA by
specifying a filter during the dump.
The kernel is in charge to filter SA, this avoids to generate useless netlink
traffic (it save also some cpu cycles). This is particularly useful when there
is a big number of SA set on the system.

Note that I removed the union in struct xfrm_state_walk to fix a problem on arm.
struct netlink_callback->args is defined as a array of 6 long and the first long
is used in xfrm code to flag the cb as initialized. Hence, we must have:
sizeof(struct xfrm_state_walk) <= sizeof(long) * 5.
With the union, it was false on arm (sizeof(struct xfrm_state_walk) was
sizeof(long) * 7), due to the padding.
In fact, whatever the arch is, this union seems useless, there will be always
padding after it. Removing it will not increase the size of this struct (and
reduce it on arm).

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 5313ccf..45332ac 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -118,11 +118,10 @@
 struct xfrm_state_walk {
 	struct list_head	all;
 	u8			state;
-	union {
-		u8		dying;
-		u8		proto;
-	};
+	u8			dying;
+	u8			proto;
 	u32			seq;
+	struct xfrm_filter	*filter;
 };
 
 /* Full description of state of transformer. */
@@ -1406,7 +1405,8 @@ static inline void xfrm_sysctl_fini(struct net *net)
 }
 #endif
 
-void xfrm_state_walk_init(struct xfrm_state_walk *walk, u8 proto);
+void xfrm_state_walk_init(struct xfrm_state_walk *walk, u8 proto,
+			  struct xfrm_filter *filter);
 int xfrm_state_walk(struct net *net, struct xfrm_state_walk *walk,
 		    int (*func)(struct xfrm_state *, int, void*), void *);
 void xfrm_state_walk_done(struct xfrm_state_walk *walk, struct net *net);