GBP: iVXLAN reflection check

packets should not egress on an iVXLAN tunnel if they
arrived on one.

Change-Id: I9adca30252364b4878f99e254aebc73b70a5d4d6
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet/vxlan-gbp/vxlan_gbp.h b/src/vnet/vxlan-gbp/vxlan_gbp.h
index 6580f38..af2e180 100644
--- a/src/vnet/vxlan-gbp/vxlan_gbp.h
+++ b/src/vnet/vxlan-gbp/vxlan_gbp.h
@@ -226,6 +226,17 @@
 void vnet_int_vxlan_gbp_bypass_mode (u32 sw_if_index, u8 is_ip6,
 				     u8 is_enable);
 
+always_inline u32
+vxlan_gbp_tunnel_by_sw_if_index (u32 sw_if_index)
+{
+  vxlan_gbp_main_t *vxm = &vxlan_gbp_main;
+
+  if (sw_if_index >= vec_len (vxm->tunnel_index_by_sw_if_index))
+    return ~0;
+
+  return (vxm->tunnel_index_by_sw_if_index[sw_if_index]);
+}
+
 #endif /* included_vnet_vxlan_gbp_h */
 
 /*