Fix parameter mismatch in map-t code

Change-Id: Ifa37767eb2c3cfc343f54691e6042473a6adf474
Signed-off-by: Juraj Sloboda <jsloboda@cisco.com>
diff --git a/src/vnet/map/ip6_map_t.c b/src/vnet/map/ip6_map_t.c
index b173bb2..8ff1532 100644
--- a/src/vnet/map/ip6_map_t.c
+++ b/src/vnet/map/ip6_map_t.c
@@ -189,7 +189,7 @@
 	  d0 =
 	    pool_elt_at_index (map_main.domains,
 			       vnet_buffer (p0)->map_t.map_domain_index);
-	  ctx0.sender_port = ip6_get_port (ip60, 0, len0);
+	  ctx0.sender_port = ip6_get_port (ip60, 0, p0->current_length);
 	  ctx0.d = d0;
 	  if (ctx0.sender_port == 0)
 	    {