[XFRM]: Export SAD info.

On a system with a lot of SAs, counting SAD entries chews useful
CPU time since you need to dump the whole SAD to user space;
i.e something like ip xfrm state ls | grep -i src | wc -l
I have seen taking literally minutes on a 40K SAs when the system
is swapping.
With this patch, some of the SAD info (that was already being tracked)
is exposed to user space. i.e you do:
ip xfrm state count
And you get the count; you can also pass -s to the command line and
get the hash info.

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 743f07e7f69..f3a61ebd8d6 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -421,6 +421,16 @@ restart:
 }
 EXPORT_SYMBOL(xfrm_state_flush);
 
+void xfrm_sad_getinfo(struct xfrm_sadinfo *si)
+{
+        spin_lock_bh(&xfrm_state_lock);
+        si->sadcnt = xfrm_state_num;
+        si->sadhcnt = xfrm_state_hmask;
+        si->sadhmcnt = xfrm_state_hashmax;
+        spin_unlock_bh(&xfrm_state_lock);
+}
+EXPORT_SYMBOL(xfrm_sad_getinfo);
+
 static int
 xfrm_init_tempsel(struct xfrm_state *x, struct flowi *fl,
                   struct xfrm_tmpl *tmpl,