[XFRM]: Introduce XFRM_MSG_REPORT.

XFRM_MSG_REPORT is a message as notification of state protocol and
selector from kernel to user-space.

Mobile IPv6 will use it when inbound reject is occurred at route
optimization to make user-space know a binding error requirement.

Based on MIPL2 kernel patch.

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 3da89c0..a26ef69 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1055,6 +1055,25 @@
 }
 EXPORT_SYMBOL(km_policy_expired);
 
+int km_report(u8 proto, struct xfrm_selector *sel, xfrm_address_t *addr)
+{
+	int err = -EINVAL;
+	int ret;
+	struct xfrm_mgr *km;
+
+	read_lock(&xfrm_km_lock);
+	list_for_each_entry(km, &xfrm_km_list, list) {
+		if (km->report) {
+			ret = km->report(proto, sel, addr);
+			if (!ret)
+				err = ret;
+		}
+	}
+	read_unlock(&xfrm_km_lock);
+	return err;
+}
+EXPORT_SYMBOL(km_report);
+
 int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optval, int optlen)
 {
 	int err;