IP Multicast FIB (mfib)

 - IPv[46] mfib tables with support for (*,G/m), (*,G) and (S,G) exact and longest prefix match
 - Replication represented via a new replicate DPO.
 - RPF configuration and data-plane checking
 - data-plane signals sent to listening control planes.

The functions of multicast forwarding entries differ from their unicast conterparts, so we introduce a new mfib_table_t and mfib_entry_t objects. However, we re-use the fib_path_list to resolve and build the entry's output list. the fib_path_list provides the service to construct a replicate DPO for multicast.

'make tests' is added to with two new suites; TEST=mfib, this is invocation of the CLI command 'test mfib' which deals with many path add/remove, flag set/unset scenarios, TEST=ip-mcast, data-plane forwarding tests.

Updated applications to use the new MIFB functions;
  - IPv6 NS/RA.
  - DHCPv6
 unit tests for these are undated accordingly.

Change-Id: I49ec37b01f1b170335a5697541c8fd30e6d3a961
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet/adj/adj.c b/src/vnet/adj/adj.c
index d0be0f0..a99f173 100644
--- a/src/vnet/adj/adj.c
+++ b/src/vnet/adj/adj.c
@@ -17,6 +17,7 @@
 #include <vnet/adj/adj_internal.h>
 #include <vnet/adj/adj_glean.h>
 #include <vnet/adj/adj_midchain.h>
+#include <vnet/adj/adj_mcast.h>
 #include <vnet/fib/fib_node_list.h>
 
 /*
@@ -58,8 +59,6 @@
                                    adj_get_index(adj));
 
     adj->rewrite_header.sw_if_index = ~0;
-    adj->mcast_group_index = ~0;
-    adj->saved_lookup_next_index = 0;
     adj->n_adj = 1;
     adj->lookup_next_index = 0;
 
@@ -116,6 +115,9 @@
     case IP_LOOKUP_NEXT_MIDCHAIN:
 	s = format (s, "%U", format_adj_midchain, adj_index, 2);
 	break;
+    case IP_LOOKUP_NEXT_MCAST:
+	s = format (s, "%U", format_adj_mcast, adj_index, 0);
+	break;
     default:
 	break;
     }
@@ -179,6 +181,10 @@
 	adj_glean_remove(adj->ia_nh_proto,
 			 adj->rewrite_header.sw_if_index);
 	break;
+    case IP_LOOKUP_NEXT_MCAST:
+	adj_mcast_remove(adj->ia_nh_proto,
+			 adj->rewrite_header.sw_if_index);
+	break;
     default:
 	/*
 	 * type not stored in any DB from which we need to remove it
@@ -350,6 +356,7 @@
     adj_nbr_module_init();
     adj_glean_module_init();
     adj_midchain_module_init();
+    adj_mcast_module_init();
 
     /*
      * one special adj to reserve index 0