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, 372 insertions, 0 deletions

diff --git a/src/vnet/ip/ip6_ll_table.c b/src/vnet/ip/ip6_ll_table.c
new file mode 100644
index 00000000000..67d05ed390f
--- /dev/null
+++ b/src/vnet/ip/ip6_ll_table.c
@@ -0,0 +1,372 @@
+/*
+ * 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.
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/dpo/drop_dpo.h>
+#include <vnet/fib/ip6_fib.h>
+
+#include <vnet/ip/ip6_ll_table.h>
+
+/**
+ * There's only one IP6 link local table
+ */
+static ip6_ll_table_t ip6_ll_table;
+
+u32
+ip6_ll_fib_get (u32 sw_if_index)
+{
+  ASSERT (vec_len (ip6_ll_table.ilt_fibs) > sw_if_index);
+
+  return (ip6_ll_table.ilt_fibs[sw_if_index]);
+}
+
+fib_node_index_t
+ip6_ll_table_lookup (const ip6_ll_prefix_t * prefix)
+{
+  return (ip6_fib_table_lookup (ip6_ll_fib_get (prefix->ilp_sw_if_index),
+				&prefix->ilp_addr, 128));
+}
+
+fib_node_index_t
+ip6_ll_table_lookup_exact_match (const ip6_ll_prefix_t * prefix)
+{
+  return (ip6_fib_table_lookup_exact_match
+	  (ip6_ll_fib_get (prefix->ilp_sw_if_index), &prefix->ilp_addr, 128));
+}
+
+static void
+ip6_ll_fib_create (u32 sw_if_index)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  u8 *desc;
+
+  desc = format (NULL, "IP6-link-local:%U",
+		 format_vnet_sw_interface_name,
+		 vnm, vnet_get_sw_interface (vnm, sw_if_index));
+
+  ip6_ll_table.ilt_fibs[sw_if_index] =
+    ip6_fib_table_create_and_lock (FIB_SOURCE_IP6_ND,
+				   FIB_TABLE_FLAG_IP6_LL, desc);
+
+  /*
+   * leave the default route as a drop, but fix fe::/10 to be a glean
+   * via the interface.
+   */
+    /* *INDENT-OFF* */
+    fib_prefix_t pfx = {
+	.fp_proto = FIB_PROTOCOL_IP6,
+	.fp_len = 10,
+	.fp_addr = {
+	    .ip6 = {
+		.as_u8 = {
+                    [0] = 0xFE,
+                    [1] = 0x80,
+                }
+	    },
+	}
+    };
+    fib_table_entry_update_one_path(
+        ip6_ll_table.ilt_fibs[sw_if_index],
+        &pfx,
+        FIB_SOURCE_SPECIAL,
+        (FIB_ENTRY_FLAG_ATTACHED |
+         FIB_ENTRY_FLAG_NO_ATTACHED_EXPORT),
+        DPO_PROTO_IP6,
+        NULL,
+        sw_if_index,
+        ~0,
+        1,
+        NULL,
+        FIB_ROUTE_PATH_FLAG_NONE);
+    /* *INDENT-ON* */
+}
+
+static void
+ip6_ll_prefix_to_fib (const ip6_ll_prefix_t * ilp, fib_prefix_t * fp)
+{
+  fp->fp_proto = FIB_PROTOCOL_IP6;
+  fp->fp_len = 128;
+  fp->fp_addr.ip6 = ilp->ilp_addr;
+}
+
+fib_node_index_t
+ip6_ll_table_entry_update (const ip6_ll_prefix_t * ilp,
+			   fib_route_path_flags_t flags)
+{
+  fib_node_index_t ip6_ll_entry_index;
+  fib_route_path_t *rpaths, rpath = {
+    .frp_flags = flags,
+    .frp_sw_if_index = ilp->ilp_sw_if_index,
+    .frp_proto = DPO_PROTO_IP6,
+  };
+  fib_prefix_t fp;
+
+  vec_validate (ip6_ll_table.ilt_fibs, ilp->ilp_sw_if_index);
+
+  if (0 == ip6_ll_fib_get (ilp->ilp_sw_if_index))
+    {
+      ip6_ll_fib_create (ilp->ilp_sw_if_index);
+    }
+
+  rpaths = NULL;
+  vec_add1 (rpaths, rpath);
+
+  ip6_ll_prefix_to_fib (ilp, &fp);
+  ip6_ll_entry_index =
+    fib_table_entry_update (ip6_ll_fib_get (ilp->ilp_sw_if_index), &fp,
+			    FIB_SOURCE_IP6_ND,
+			    (flags & FIB_ROUTE_PATH_LOCAL ?
+			     FIB_ENTRY_FLAG_LOCAL : FIB_ENTRY_FLAG_NONE),
+			    rpaths);
+  vec_free (rpaths);
+
+  return (ip6_ll_entry_index);
+}
+
+void
+ip6_ll_table_entry_delete (const ip6_ll_prefix_t * ilp)
+{
+  fib_node_index_t ip6_ll_entry_index;
+  u32 fib_index;
+
+  ip6_ll_entry_index = ip6_ll_table_lookup_exact_match (ilp);
+
+  if (FIB_NODE_INDEX_INVALID != ip6_ll_entry_index)
+    fib_table_entry_delete_index (ip6_ll_entry_index, FIB_SOURCE_IP6_ND);
+
+  /*
+   * if there are no ND sourced prefixes left, then we can clean up this FIB
+   */
+  fib_index = ip6_ll_fib_get (ilp->ilp_sw_if_index);
+  if (0 == fib_table_get_num_entries (fib_index,
+				      FIB_PROTOCOL_IP6, FIB_SOURCE_IP6_ND))
+    {
+      fib_table_unlock (fib_index, FIB_PROTOCOL_IP6, FIB_SOURCE_IP6_ND);
+      ip6_ll_table.ilt_fibs[ilp->ilp_sw_if_index] = 0;
+    }
+}
+
+static void
+ip6_ll_table_show_one (vlib_main_t * vm, ip6_ll_prefix_t * ilp, int detail)
+{
+  vlib_cli_output (vm, "%U",
+		   format_fib_entry,
+		   ip6_ll_table_lookup (ilp),
+		   (detail ?
+		    FIB_ENTRY_FORMAT_DETAIL2 : FIB_ENTRY_FORMAT_DETAIL));
+}
+
+typedef struct ip6_ll_show_ctx_t_
+{
+  fib_node_index_t *entries;
+} ip6_ll_show_ctx_t;
+
+static fib_table_walk_rc_t
+ip6_ll_table_show_walk (fib_node_index_t fib_entry_index, void *arg)
+{
+  ip6_ll_show_ctx_t *ctx = arg;
+
+  vec_add1 (ctx->entries, fib_entry_index);
+
+  return (FIB_TABLE_WALK_CONTINUE);
+}
+
+static void
+ip6_ll_table_show_all (vlib_main_t * vm, u32 fib_index)
+{
+  fib_node_index_t *fib_entry_index;
+  ip6_ll_show_ctx_t ctx = {
+    .entries = NULL,
+  };
+
+  fib_table_walk (fib_index, FIB_PROTOCOL_IP6, ip6_ll_table_show_walk, &ctx);
+  vec_sort_with_function (ctx.entries, fib_entry_cmp_for_sort);
+
+  vec_foreach (fib_entry_index, ctx.entries)
+  {
+    vlib_cli_output (vm, "%U",
+		     format_fib_entry,
+		     *fib_entry_index, FIB_ENTRY_FORMAT_BRIEF);
+  }
+
+  vec_free (ctx.entries);
+}
+
+typedef struct
+{
+  u32 fib_index;
+  u64 count_by_prefix_length[129];
+} count_routes_in_fib_at_prefix_length_arg_t;
+
+static void
+count_routes_in_fib_at_prefix_length (BVT (clib_bihash_kv) * kvp, void *arg)
+{
+  count_routes_in_fib_at_prefix_length_arg_t *ap = arg;
+  int mask_width;
+
+  if ((kvp->key[2] >> 32) != ap->fib_index)
+    return;
+
+  mask_width = kvp->key[2] & 0xFF;
+
+  ap->count_by_prefix_length[mask_width]++;
+}
+
+static clib_error_t *
+ip6_ll_show_fib (vlib_main_t * vm,
+		 unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  count_routes_in_fib_at_prefix_length_arg_t _ca, *ca = &_ca;
+  ip6_main_t *im6 = &ip6_main;
+  fib_table_t *fib_table;
+  int verbose, matching;
+  ip6_address_t matching_address;
+  u32 mask_len = 128;
+  u32 sw_if_index = ~0;
+  int detail = 0;
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 fib_index;
+
+  verbose = 1;
+  matching = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "brief") ||
+	  unformat (input, "summary") || unformat (input, "sum"))
+	verbose = 0;
+
+      else if (unformat (input, "detail") || unformat (input, "det"))
+	detail = 1;
+
+      else if (unformat (input, "%U/%d",
+			 unformat_ip6_address, &matching_address, &mask_len))
+	matching = 1;
+
+      else
+	if (unformat (input, "%U", unformat_ip6_address, &matching_address))
+	matching = 1;
+      else if (unformat (input, "%U",
+			 unformat_vnet_sw_interface, vnm, &sw_if_index))
+	;
+      else
+	break;
+    }
+
+  vec_foreach_index (sw_if_index, ip6_ll_table.ilt_fibs)
+  {
+    fib_source_t source;
+    u8 *s = NULL;
+
+    fib_index = ip6_ll_table.ilt_fibs[sw_if_index];
+
+    if (0 == fib_index)
+      continue;
+
+    fib_table = fib_table_get (fib_index, FIB_PROTOCOL_IP6);
+
+    if (!(fib_table->ft_flags & FIB_TABLE_FLAG_IP6_LL))
+      continue;
+
+    s = format (s, "%U, fib_index:%d, locks:[",
+		format_fib_table_name, fib_index,
+		FIB_PROTOCOL_IP6, fib_index);
+    FOR_EACH_FIB_SOURCE (source)
+    {
+      if (0 != fib_table->ft_locks[source])
+	{
+	  s = format (s, "%U:%d, ",
+		      format_fib_source, source, fib_table->ft_locks[source]);
+	}
+    }
+    s = format (s, "]");
+    vlib_cli_output (vm, "%v", s);
+    vec_free (s);
+
+    /* Show summary? */
+    if (!verbose)
+      {
+	BVT (clib_bihash) * h =
+	  &im6->ip6_table[IP6_FIB_TABLE_NON_FWDING].ip6_hash;
+	int len;
+
+	vlib_cli_output (vm, "%=20s%=16s", "Prefix length", "Count");
+
+	memset (ca, 0, sizeof (*ca));
+	ca->fib_index = fib_index;
+
+	BV (clib_bihash_foreach_key_value_pair)
+	  (h, count_routes_in_fib_at_prefix_length, ca);
+
+	for (len = 128; len >= 0; len--)
+	  {
+	    if (ca->count_by_prefix_length[len])
+	      vlib_cli_output (vm, "%=20d%=16lld",
+			       len, ca->count_by_prefix_length[len]);
+	  }
+	continue;
+      }
+
+    if (!matching)
+      {
+	ip6_ll_table_show_all (vm, fib_index);
+      }
+    else
+      {
+	if (~0 == sw_if_index)
+	  {
+	    vlib_cli_output (vm, "specify the interface");
+	  }
+	else
+	  {
+	    ip6_ll_prefix_t ilp = {
+	      .ilp_addr = matching_address,
+	      .ilp_sw_if_index = sw_if_index,
+	    };
+	    ip6_ll_table_show_one (vm, &ilp, detail);
+	  }
+      }
+  };
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (ip6_show_fib_command, static) = {
+    .path = "show ip6-ll",
+    .short_help = "show ip6-ll [summary] [interface] [<ip6-addr>[/<width>]] [detail]",
+    .function = ip6_ll_show_fib,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+ip6_ll_module_init (vlib_main_t * vm)
+{
+  clib_error_t *error;
+
+  error = vlib_call_init_function (vm, ip6_lookup_init);
+
+  return (error);
+}
+
+VLIB_INIT_FUNCTION (ip6_ll_module_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */