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>

8 files changed, 436 insertions, 106 deletions

diff --git a/src/vnet/adj/adj.c b/src/vnet/adj/adj.c
index d0be0f0eaff..a99f173f6d0 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_alloc (fib_protocol_t proto)
                                    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 @@ format_ip_adjacency (u8 * s, va_list * args)
     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_last_lock_gone (ip_adjacency_t *adj)
 	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_module_init (vlib_main_t * vm)
     adj_nbr_module_init();
     adj_glean_module_init();
     adj_midchain_module_init();
+    adj_mcast_module_init();
 
     /*
      * one special adj to reserve index 0
diff --git a/src/vnet/adj/adj.h b/src/vnet/adj/adj.h
index e85625db7ee..29bae6733b3 100644
--- a/src/vnet/adj/adj.h
+++ b/src/vnet/adj/adj.h
@@ -45,7 +45,6 @@
 #include <vnet/ip/lookup.h>
 #include <vnet/adj/adj_types.h>
 #include <vnet/adj/adj_nbr.h>
-#include <vnet/adj/adj_rewrite.h>
 #include <vnet/adj/adj_glean.h>
 
 /**
diff --git a/src/vnet/adj/adj_internal.h b/src/vnet/adj/adj_internal.h
index 833bc7c9e01..ece59121e9c 100644
--- a/src/vnet/adj/adj_internal.h
+++ b/src/vnet/adj/adj_internal.h
@@ -100,5 +100,7 @@ extern void adj_nbr_remove(adj_index_t ai,
 			   u32 sw_if_index);
 extern void adj_glean_remove(fib_protocol_t proto,
 			     u32 sw_if_index);
+extern void adj_mcast_remove(fib_protocol_t proto,
+			     u32 sw_if_index);
 
 #endif
diff --git a/src/vnet/adj/adj_mcast.c b/src/vnet/adj/adj_mcast.c
new file mode 100644
index 00000000000..1345aedbad6
--- /dev/null
+++ b/src/vnet/adj/adj_mcast.c
@@ -0,0 +1,346 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vnet/adj/adj.h>
+#include <vnet/adj/adj_internal.h>
+#include <vnet/fib/fib_walk.h>
+#include <vnet/ip/ip.h>
+
+/*
+ * The 'DB' of all mcast adjs.
+ * There is only one mcast per-interface per-protocol, so this is a per-interface
+ * vector
+ */
+static adj_index_t *adj_mcasts[FIB_PROTOCOL_MAX];
+
+static u32
+adj_get_mcast_node (fib_protocol_t proto)
+{
+    switch (proto) {
+    case FIB_PROTOCOL_IP4:
+	return (ip4_rewrite_mcast_node.index);
+    case FIB_PROTOCOL_IP6:
+	return (ip6_rewrite_mcast_node.index);
+    case FIB_PROTOCOL_MPLS:
+	break;
+    }
+    ASSERT(0);
+    return (0);
+}
+
+/*
+ * adj_mcast_add_or_lock
+ *
+ * The next_hop address here is used for source address selection in the DP.
+ * The mcast adj is added to an interface's connected prefix, the next-hop
+ * passed here is the local prefix on the same interface.
+ */
+adj_index_t
+adj_mcast_add_or_lock (fib_protocol_t proto,
+                       vnet_link_t link_type,
+		       u32 sw_if_index)
+{
+    ip_adjacency_t * adj;
+
+    vec_validate_init_empty(adj_mcasts[proto], sw_if_index, ADJ_INDEX_INVALID);
+
+    if (ADJ_INDEX_INVALID == adj_mcasts[proto][sw_if_index])
+    {
+        vnet_main_t *vnm;
+
+        vnm = vnet_get_main();
+	adj = adj_alloc(proto);
+
+	adj->lookup_next_index = IP_LOOKUP_NEXT_MCAST;
+	adj->ia_nh_proto = proto;
+	adj->ia_link = link_type;
+	adj_mcasts[proto][sw_if_index] = adj_get_index(adj);
+        adj_lock(adj_get_index(adj));
+
+	vnet_rewrite_init(vnm, sw_if_index,
+			  adj_get_mcast_node(proto),
+			  vnet_tx_node_index_for_sw_interface(vnm, sw_if_index),
+			  &adj->rewrite_header);
+
+	/*
+	 * we need a rewrite where the destination IP address is converted
+	 * to the appropriate link-layer address. This is interface specific.
+	 * So ask the interface to do it.
+	 */
+	vnet_update_adjacency_for_sw_interface(vnm, sw_if_index,
+                                               adj_get_index(adj));
+    }
+    else
+    {
+	adj = adj_get(adj_mcasts[proto][sw_if_index]);
+        adj_lock(adj_get_index(adj));
+    }
+
+    return (adj_get_index(adj));
+}
+
+/**
+ * adj_mcast_update_rewrite
+ *
+ * Update the adjacency's rewrite string. A NULL string implies the
+ * rewirte is reset (i.e. when ARP/ND etnry is gone).
+ * NB: the adj being updated may be handling traffic in the DP.
+ */
+void
+adj_mcast_update_rewrite (adj_index_t adj_index,
+                          u8 *rewrite)
+{
+    ip_adjacency_t *adj;
+
+    ASSERT(ADJ_INDEX_INVALID != adj_index);
+
+    adj = adj_get(adj_index);
+
+    /*
+     * update the adj's rewrite string and build the arc
+     * from the rewrite node to the interface's TX node
+     */
+    adj_nbr_update_rewrite_internal(adj, IP_LOOKUP_NEXT_MCAST,
+                                    adj_get_mcast_node(adj->ia_nh_proto),
+                                    vnet_tx_node_index_for_sw_interface(
+                                        vnet_get_main(),
+                                        adj->rewrite_header.sw_if_index),
+                                    rewrite);
+}
+
+void
+adj_mcast_remove (fib_protocol_t proto,
+		  u32 sw_if_index)
+{
+    ASSERT(sw_if_index < vec_len(adj_mcasts[proto]));
+
+    adj_mcasts[proto][sw_if_index] = ADJ_INDEX_INVALID;
+}
+
+static clib_error_t *
+adj_mcast_interface_state_change (vnet_main_t * vnm,
+				  u32 sw_if_index,
+				  u32 flags)
+{
+    /*
+     * for each mcast on the interface trigger a walk back to the children
+     */
+    fib_protocol_t proto;
+    ip_adjacency_t *adj;
+
+
+    for (proto = FIB_PROTOCOL_IP4; proto <= FIB_PROTOCOL_IP6; proto++)
+    {
+	if (sw_if_index >= vec_len(adj_mcasts[proto]) ||
+	    ADJ_INDEX_INVALID == adj_mcasts[proto][sw_if_index])
+	    continue;
+
+	adj = adj_get(adj_mcasts[proto][sw_if_index]);
+
+	fib_node_back_walk_ctx_t bw_ctx = {
+	    .fnbw_reason = (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP ?
+			    FIB_NODE_BW_REASON_FLAG_INTERFACE_UP :
+			    FIB_NODE_BW_REASON_FLAG_INTERFACE_DOWN),
+	};
+
+	fib_walk_sync(FIB_NODE_TYPE_ADJ, adj_get_index(adj), &bw_ctx);
+    }
+
+    return (NULL);
+}
+
+VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION(adj_mcast_interface_state_change);
+
+/**
+ * @brief Invoked on each SW interface of a HW interface when the
+ * HW interface state changes
+ */
+static void
+adj_nbr_hw_sw_interface_state_change (vnet_main_t * vnm,
+                                      u32 sw_if_index,
+                                      void *arg)
+{
+    adj_mcast_interface_state_change(vnm, sw_if_index, (uword) arg);
+}
+
+/**
+ * @brief Registered callback for HW interface state changes
+ */
+static clib_error_t *
+adj_mcast_hw_interface_state_change (vnet_main_t * vnm,
+                                     u32 hw_if_index,
+                                     u32 flags)
+{
+    /*
+     * walk SW interfaces on the HW
+     */
+    uword sw_flags;
+
+    sw_flags = ((flags & VNET_HW_INTERFACE_FLAG_LINK_UP) ?
+                VNET_SW_INTERFACE_FLAG_ADMIN_UP :
+                0);
+
+    vnet_hw_interface_walk_sw(vnm, hw_if_index,
+                              adj_nbr_hw_sw_interface_state_change,
+                              (void*) sw_flags);
+
+    return (NULL);
+}
+
+VNET_HW_INTERFACE_LINK_UP_DOWN_FUNCTION(
+    adj_mcast_hw_interface_state_change);
+
+static clib_error_t *
+adj_mcast_interface_delete (vnet_main_t * vnm,
+			    u32 sw_if_index,
+			    u32 is_add)
+{
+    /*
+     * for each mcast on the interface trigger a walk back to the children
+     */
+    fib_protocol_t proto;
+    ip_adjacency_t *adj;
+
+    if (is_add)
+    {
+	/*
+	 * not interested in interface additions. we will not back walk
+	 * to resolve paths through newly added interfaces. Why? The control
+	 * plane should have the brains to add interfaces first, then routes.
+	 * So the case where there are paths with a interface that matches
+	 * one just created is the case where the path resolved through an
+	 * interface that was deleted, and still has not been removed. The
+	 * new interface added, is NO GUARANTEE that the interface being
+	 * added now, even though it may have the same sw_if_index, is the
+	 * same interface that the path needs. So tough!
+	 * If the control plane wants these routes to resolve it needs to
+	 * remove and add them again.
+	 */
+	return (NULL);
+    }
+
+    for (proto = FIB_PROTOCOL_IP4; proto <= FIB_PROTOCOL_IP6; proto++)
+    {
+	if (sw_if_index >= vec_len(adj_mcasts[proto]) ||
+	    ADJ_INDEX_INVALID == adj_mcasts[proto][sw_if_index])
+	    continue;
+
+	adj = adj_get(adj_mcasts[proto][sw_if_index]);
+
+	fib_node_back_walk_ctx_t bw_ctx = {
+	    .fnbw_reason =  FIB_NODE_BW_REASON_FLAG_INTERFACE_DELETE,
+	};
+
+	fib_walk_sync(FIB_NODE_TYPE_ADJ, adj_get_index(adj), &bw_ctx);
+    }
+
+    return (NULL);
+}
+
+VNET_SW_INTERFACE_ADD_DEL_FUNCTION(adj_mcast_interface_delete);
+
+u8*
+format_adj_mcast (u8* s, va_list *ap)
+{
+    index_t index = va_arg(*ap, index_t);
+    CLIB_UNUSED(u32 indent) = va_arg(*ap, u32);
+    vnet_main_t * vnm = vnet_get_main();
+    ip_adjacency_t * adj = adj_get(index);
+
+    s = format(s, "%U-mcast: ",
+               format_fib_protocol, adj->ia_nh_proto);
+    s = format (s, "%U",
+		format_vnet_rewrite,
+		vnm->vlib_main, &adj->rewrite_header,
+                sizeof (adj->rewrite_data), 0);
+
+    return (s);
+}
+
+
+static void
+adj_dpo_lock (dpo_id_t *dpo)
+{
+    adj_lock(dpo->dpoi_index);
+}
+static void
+adj_dpo_unlock (dpo_id_t *dpo)
+{
+    adj_unlock(dpo->dpoi_index);
+}
+
+const static dpo_vft_t adj_mcast_dpo_vft = {
+    .dv_lock = adj_dpo_lock,
+    .dv_unlock = adj_dpo_unlock,
+    .dv_format = format_adj_mcast,
+};
+
+/**
+ * @brief The per-protocol VLIB graph nodes that are assigned to a mcast
+ *        object.
+ *
+ * this means that these graph nodes are ones from which a mcast is the
+ * parent object in the DPO-graph.
+ */
+const static char* const adj_mcast_ip4_nodes[] =
+{
+    "ip4-rewrite-mcast",
+    NULL,
+};
+const static char* const adj_mcast_ip6_nodes[] =
+{
+    "ip6-rewrite-mcast",
+    NULL,
+};
+
+const static char* const * const adj_mcast_nodes[DPO_PROTO_NUM] =
+{
+    [DPO_PROTO_IP4]  = adj_mcast_ip4_nodes,
+    [DPO_PROTO_IP6]  = adj_mcast_ip6_nodes,
+    [DPO_PROTO_MPLS] = NULL,
+};
+
+/**
+ * @brief Return the size of the adj DB.
+ * This is only for testing purposes so an efficient implementation is not needed
+ */
+u32
+adj_mcast_db_size (void)
+{
+    u32 n_adjs, sw_if_index;
+    fib_protocol_t proto;
+
+    n_adjs = 0;
+    for (proto = FIB_PROTOCOL_IP4; proto <= FIB_PROTOCOL_IP6; proto++)
+    {
+        for (sw_if_index = 0;
+             sw_if_index < vec_len(adj_mcasts[proto]);
+             sw_if_index++)
+        {
+            if (ADJ_INDEX_INVALID != adj_mcasts[proto][sw_if_index])
+            {
+                n_adjs++;
+            }
+        }
+    }
+    
+    return (n_adjs);
+}
+
+void
+adj_mcast_module_init (void)
+{
+    dpo_register(DPO_ADJACENCY_MCAST, &adj_mcast_dpo_vft, adj_mcast_nodes);
+}
diff --git a/src/vnet/adj/adj_mcast.h b/src/vnet/adj/adj_mcast.h
new file mode 100644
index 00000000000..21c5a1417dd
--- /dev/null
+++ b/src/vnet/adj/adj_mcast.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @brief Mcast Adjacency
+ *
+ * The multicast adjacency forwards IP traffic on an interface toward a multicast
+ * group address. This is a different type of adjacency to a unicast adjacency
+ * since the application of the MAC header is different, and so the VLIB node
+ * visited is also different. DPO types have different VLIB nodes.
+ */
+
+#ifndef __ADJ_MCAST_H__
+#define __ADJ_MCAST_H__
+
+#include <vnet/adj/adj_types.h>
+
+/**
+ * @brief
+ *  Add (and lock) a new or lock an existing mcast adjacency
+ *
+ * @param proto
+ *  The protocol for the neighbours that we wish to mcast
+ *
+ * @param link_type
+ *  A description of the protocol of the packets that will forward
+ *  through this adj. On an ethernet interface this is the MAC header's
+ *  ether-type
+ *
+ * @param sw_if_index
+ *  The interface on which to mcast
+ */
+extern adj_index_t adj_mcast_add_or_lock(fib_protocol_t proto,
+                                         vnet_link_t link_type,
+					 u32 sw_if_index);
+
+/**
+ * @brief
+ *  Update the rewrite string for an existing adjacecny.
+ *
+ * @param
+ *  The index of the adj to update
+ *
+ * @param
+ *  The new rewrite
+ */
+extern void adj_mcast_update_rewrite(adj_index_t adj_index,
+                                     u8 *rewrite);
+
+/**
+ * @brief Format/display a mcast adjacency.
+ */
+extern u8* format_adj_mcast(u8* s, va_list *ap);
+
+/**
+ * @brief Get the sze of the mcast adj DB. Test purposes only.
+ */
+extern u32 adj_mcast_db_size(void);
+
+/**
+ * @brief
+ *  Module initialisation
+ */
+extern void adj_mcast_module_init(void);
+
+#endif
diff --git a/src/vnet/adj/adj_nbr.c b/src/vnet/adj/adj_nbr.c
index 1344bb67fcc..9e8073d3225 100644
--- a/src/vnet/adj/adj_nbr.c
+++ b/src/vnet/adj/adj_nbr.c
@@ -162,7 +162,7 @@ adj_nbr_alloc (fib_protocol_t nh_proto,
 }
 
 /*
- * adj_add_for_nbr
+ * adj_nbr_add_or_lock
  *
  * Add an adjacency for the neighbour requested.
  *
diff --git a/src/vnet/adj/adj_rewrite.c b/src/vnet/adj/adj_rewrite.c
deleted file mode 100644
index 7d792557724..00000000000
--- a/src/vnet/adj/adj_rewrite.c
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * Copyright (c) 2016 Cisco and/or its affiliates.
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at:
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <vnet/adj/adj.h>
-#include <vnet/adj/adj_internal.h>
-
-/**
- * adj_rewrite_add_and_lock
- *
- * A rewrite sub-type has the rewrite string provided, but no key
- */
-adj_index_t
-adj_rewrite_add_and_lock (fib_protocol_t nh_proto,
-			  vnet_link_t link_type,
-			  u32 sw_if_index,
-			  u8 *rewrite)
-{
-    ip_adjacency_t *adj;
-
-    adj = adj_alloc(nh_proto);
-
-    adj->lookup_next_index = IP_LOOKUP_NEXT_REWRITE;
-    memset(&adj->sub_type.nbr.next_hop, 0, sizeof(adj->sub_type.nbr.next_hop));
-    adj->ia_link = link_type;
-    adj->ia_nh_proto = nh_proto;
-    adj->rewrite_header.sw_if_index = sw_if_index;
-
-    ASSERT(NULL != rewrite);
-
-    vnet_rewrite_for_sw_interface(vnet_get_main(),
-				  link_type,
-				  adj->rewrite_header.sw_if_index,
-				  adj_get_rewrite_node(link_type),
-				  rewrite,
-				  &adj->rewrite_header,
-				  sizeof (adj->rewrite_data));
-
-    adj_lock(adj_get_index(adj));
-
-    return (adj_get_index(adj));
-}
diff --git a/src/vnet/adj/adj_rewrite.h b/src/vnet/adj/adj_rewrite.h
deleted file mode 100644
index 25e6bba8868..00000000000
--- a/src/vnet/adj/adj_rewrite.h
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * Copyright (c) 2016 Cisco and/or its affiliates.
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at:
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-/**
- * @brief
- * A rewrite adjacency has no key, and thus cannot be 'found' from the
- * FIB resolution code. the client therefore needs to maange these adjacencies
- */
-
-#ifndef __ADJ_REWRITE_H__
-#define __ADJ_REWRITE_H__
-
-#include <vnet/adj/adj_types.h>
-
-/**
- * @brief
- *  Add (and lock) a new or lock an existing neighbour adjacency
- *
- * @param nh_proto
- *  The protocol for the next-hop address (v4 or v6)
- *
- * @param link_type
- *  A description of the protocol of the packets that will forward
- *  through this adj. On an ethernet interface this is the MAC header's
- *  ether-type
- *
- * @param sw_if_index
- *  The interface on which the peer resides
- *
- * @param rewrite
- *  The rewrite to prepend to packets
- */
-extern adj_index_t adj_rewrite_add_and_lock(fib_protocol_t nh_proto,
-					    vnet_link_t link_type,
-					    u32 sw_if_index,
-					    u8 *rewrite);
-
-#endif