Add logging support

Change-Id: Ieac9cf50156dbbb4962411e900d59256441915ef
Signed-off-by: Damjan Marion <damarion@cisco.com>
Signed-off-by: Klement Sekera <ksekera@cisco.com>
diff --git a/src/vnet/devices/tap/tap.h b/src/vnet/devices/tap/tap.h
index 98af0d8..6e46302 100644
--- a/src/vnet/devices/tap/tap.h
+++ b/src/vnet/devices/tap/tap.h
@@ -69,6 +69,9 @@
 {
   u32 last_used_interface_id;
   uword *dev_instance_by_interface_id;
+
+  /* logging */
+  vlib_log_class_t log_default;
 } tap_main_t;
 
 void tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args);