Implement DHCPv6 PD client (VPP-718, VPP-1050)

Change-Id: I72a1ccdfdd5573335ef78fc01d5268934c73bd31
Signed-off-by: Juraj Sloboda <jsloboda@cisco.com>
diff --git a/src/vnet/ip/ip6_neighbor.h b/src/vnet/ip/ip6_neighbor.h
index 27d8cb2..b346563 100644
--- a/src/vnet/ip/ip6_neighbor.h
+++ b/src/vnet/ip/ip6_neighbor.h
@@ -44,6 +44,8 @@
   fib_node_index_t fib_entry_index;
 } ip6_neighbor_t;
 
+extern ip6_address_t ip6_neighbor_get_link_local_address (u32 sw_if_index);
+
 extern ip6_neighbor_t *ip6_neighbors_pool (void);
 
 extern ip6_neighbor_t *ip6_neighbors_entries (u32 sw_if_index);