interface: add support for outer header checksums

Type: improvement

Change-Id: I7c341dc4a99898dd1f865ac2ebd99de9898bb0bd
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
diff --git a/src/vnet/interface_output.c b/src/vnet/interface_output.c
index 5b43f7e..72ceb95 100644
--- a/src/vnet/interface_output.c
+++ b/src/vnet/interface_output.c
@@ -170,6 +170,7 @@
 {
   vnet_calc_checksums_inline (vm, b, b->flags & VNET_BUFFER_F_IS_IP4,
 			      b->flags & VNET_BUFFER_F_IS_IP6);
+  vnet_calc_outer_checksums_inline (vm, b);
 }
 
 static_always_inline uword