net: export attach/detach filter routines

Export sk_attach_filter/sk_detach_filter routines,
so that tun module can use them.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/filter.c

@@ -529,6 +529,7 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
 		sk_filter_delayed_uncharge(sk, old_fp);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(sk_attach_filter);
 
 int sk_detach_filter(struct sock *sk)
 {
@@ -545,3 +546,4 @@ int sk_detach_filter(struct sock *sk)
 	rcu_read_unlock_bh();
 	return ret;
 }
+EXPORT_SYMBOL_GPL(sk_detach_filter);