BFD: loop back echo packets

Change-Id: I772b63ac25ebfccaff9ab9d8d0b1445e85f21df7
Signed-off-by: Klement Sekera <ksekera@cisco.com>
diff --git a/src/vnet/bfd/bfd_udp.h b/src/vnet/bfd/bfd_udp.h
index 26e8985..502e231 100644
--- a/src/vnet/bfd/bfd_udp.h
+++ b/src/vnet/bfd/bfd_udp.h
@@ -40,6 +40,13 @@
   adj_index_t adj_index;
 } bfd_udp_session_t;
 
+/* bfd udp echo packet trace capture */
+typedef struct
+{
+  u32 len;
+  u8 data[400];
+} bfd_udp_echo_input_trace_t;
+
 struct bfd_session_s;
 
 void bfd_add_udp4_transport (vlib_main_t * vm, vlib_buffer_t * b,