netns xfrm: lookup in netns

Pass netns to xfrm_lookup()/__xfrm_lookup(). For that pass netns
to flow_cache_lookup() and resolver callback.

Take it from socket or netdevice. Stub DECnet to init_net.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 768df00..eeaa3d8 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1184,7 +1184,7 @@
 
 	err = __dn_route_output_key(pprt, flp, flags);
 	if (err == 0 && flp->proto) {
-		err = xfrm_lookup(pprt, flp, NULL, 0);
+		err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);
 	}
 	return err;
 }
@@ -1195,8 +1195,8 @@
 
 	err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
 	if (err == 0 && fl->proto) {
-		err = xfrm_lookup(pprt, fl, sk, (flags & MSG_DONTWAIT) ?
-						0 : XFRM_LOOKUP_WAIT);
+		err = xfrm_lookup(&init_net, pprt, fl, sk,
+				 (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);
 	}
 	return err;
 }