IP6 link-local table

- IPv6 link local table is a per-SW interface array of IPv6 unicast FIBs
- the per-interface ocst is sizeof(fib_table_t) which is small,
  w.r.t. the cost of an interface
- FE80::/10 in the 'global' table points to a DPO that performs a lookup in the
  input interface's LL fib.

Change-Id: Ice834b25ebeeacb2e929d7c864d7ec8c09918cbe
Signed-off-by: Neale Ranns <neale.ranns@cisco.com>

1 files changed, 203 insertions, 0 deletions

diff --git a/src/vnet/dpo/ip6_ll_dpo.c b/src/vnet/dpo/ip6_ll_dpo.c
new file mode 100644
index 00000000000..f86472c16c5
--- /dev/null
+++ b/src/vnet/dpo/ip6_ll_dpo.c
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2018 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
+ * The data-path object representing performing a lookup in the IPv6
+ * link local table
+ */
+
+#include <vnet/dpo/ip6_ll_dpo.h>
+#include <vnet/ip/ip6_ll_table.h>
+
+/**
+ * @brief the IP6 link-local DPO is global
+ */
+static dpo_id_t ip6_ll_dpo = {
+  .dpoi_type = DPO_IP6_LL,
+  .dpoi_proto = DPO_PROTO_IP6,
+  .dpoi_index = 0,
+};
+
+const dpo_id_t *
+ip6_ll_dpo_get (void)
+{
+  return (&ip6_ll_dpo);
+}
+
+static void
+ip6_ll_dpo_lock (dpo_id_t * dpo)
+{
+  /*
+   * not maintaining a lock count on the ip6_ll, they are const global and
+   * never die.
+   */
+}
+
+static void
+ip6_ll_dpo_unlock (dpo_id_t * dpo)
+{
+}
+
+static u8 *
+format_ip6_ll_dpo (u8 * s, va_list * ap)
+{
+  CLIB_UNUSED (index_t index) = va_arg (*ap, index_t);
+  CLIB_UNUSED (u32 indent) = va_arg (*ap, u32);
+
+  return (format (s, "ip6-link-local"));
+}
+
+const static dpo_vft_t ip6_ll_vft = {
+  .dv_lock = ip6_ll_dpo_lock,
+  .dv_unlock = ip6_ll_dpo_unlock,
+  .dv_format = format_ip6_ll_dpo,
+};
+
+/**
+ * @brief The per-protocol VLIB graph nodes that are assigned to a ip6_ll
+ *        object.
+ *
+ * this means that these graph nodes are ones from which a ip6_ll is the
+ * parent object in the DPO-graph.
+ */
+const static char *const ip6_null_nodes[] = {
+  "ip6-link-local",
+  NULL,
+};
+
+const static char *const *const ip6_ll_nodes[DPO_PROTO_NUM] = {
+  [DPO_PROTO_IP6] = ip6_null_nodes,
+};
+
+typedef struct ip6_ll_dpo_trace_t_
+{
+  u32 fib_index;
+  u32 sw_if_index;
+} ip6_ll_dpo_trace_t;
+
+/**
+ * @brief Exit nodes from a IP6_LL
+ */
+typedef enum ip6_ll_next_t_
+{
+  IP6_LL_NEXT_DROP,
+  IP6_LL_NEXT_LOOKUP,
+  IP6_LL_NEXT_NUM,
+} ip6_ll_next_t;
+
+always_inline uword
+ip6_ll_dpo_inline (vlib_main_t * vm,
+		   vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  u32 n_left_from, next_index, *from, *to_next;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0, fib_index0, next0;
+	  vlib_buffer_t *p0;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+	  next0 = IP6_LL_NEXT_LOOKUP;
+
+	  p0 = vlib_get_buffer (vm, bi0);
+
+	  /* use the packet's RX interface to pick the link-local FIB */
+	  fib_index0 =
+	    ip6_ll_fib_get (vnet_buffer (p0)->sw_if_index[VLIB_RX]);
+	  /* write that fib index into the packet so it's used in the
+	   * lookup node next */
+	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = fib_index0;
+
+	  if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      ip6_ll_dpo_trace_t *tr = vlib_add_trace (vm, node, p0,
+						       sizeof (*tr));
+	      tr->sw_if_index = vnet_buffer (p0)->sw_if_index[VLIB_RX];
+	      tr->fib_index = fib_index0;
+	    }
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  return frame->n_vectors;
+}
+
+static u8 *
+format_ip6_ll_dpo_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  ip6_ll_dpo_trace_t *t = va_arg (*args, ip6_ll_dpo_trace_t *);
+
+  s = format (s, "sw_if_index:%d fib_index:%d", t->sw_if_index, t->fib_index);
+  return s;
+}
+
+static uword
+ip6_ll_dpo_switch (vlib_main_t * vm,
+		   vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return (ip6_ll_dpo_inline (vm, node, frame));
+}
+
+/**
+ * @brief
+ */
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip6_ll_dpo_node) =
+{
+  .function = ip6_ll_dpo_switch,
+  .name = "ip6-link-local",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip6_ll_dpo_trace,
+  .n_next_nodes = IP6_LL_NEXT_NUM,
+  .next_nodes = {
+    [IP6_LL_NEXT_DROP] = "ip6-drop",
+    [IP6_LL_NEXT_LOOKUP] = "ip6-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+void
+ip6_ll_dpo_module_init (void)
+{
+  dpo_register (DPO_IP6_LL, &ip6_ll_vft, ip6_ll_nodes);
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */