[router] IPv6 support and refactoring.

This change adds support for IPv6 while refactoring most of the
original plugin code in the following ways.

 - Adhere to vpp style guidelines.

 - Split the netlink, node, and tap processing into separate
   files named with a "tap_inject" prefix which more accurately
   represents the functionality.

 - Implement our own tap management and rx/tx. This is to reduce
   the overhead of passing packets in and out of vnet tap
   devices, in favor of directly reading/writing from the tap.

 - Change how nodes work. Now we have neighbor, rx, and tx nodes.
   The neighbor node sends ARP replies and ICMP6 neighbor
   advertisements to the arp-input and icmp6-neighbor-solicitation
   nodes, respectively, before also injecting the packet to the
   host, making it possible for both vpp and the host network stack
   to resolve the next hop. The tx node injects packets into the
   host by writing to the tap. The rx node reads packets from the
   tap and sends them on its associated data plane interface.

 - Simplify the CLI. Instead of creating taps specifically for
   a given interface we create a tap for all of the Ethernet
   interfaces with the "enable tap-inject" CLI command. The
   interfaces are named with a "vpp" prefix, i.e. "vpp0". Also
   add a "disable tap-inject" option.

 - Provide ability to enable at configuration time with the
   tap-inject { enable } stanza.

Change-Id: I6b56da606e2da1d793ce6aca222fe4eb5a4e070d
Signed-off-by: Jeff Shaw <jeffrey.b.shaw@intel.com>

1 files changed, 375 insertions, 0 deletions

diff --git a/router/router/tap_inject.c b/router/router/tap_inject.c
new file mode 100644
index 0000000..8d6f5af
--- /dev/null
+++ b/router/router/tap_inject.c
@@ -0,0 +1,375 @@
+/*
+ * Copyright 2016 Intel Corporation
+ *
+ * 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 "tap_inject.h"
+
+static tap_inject_main_t tap_inject_main;
+
+tap_inject_main_t *
+tap_inject_get_main (void)
+{
+  return &tap_inject_main;
+}
+
+void
+tap_inject_insert_tap (u32 sw_if_index, u32 tap_fd, u32 tap_if_index)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  vec_validate_init_empty (im->sw_if_index_to_tap_fd, sw_if_index, ~0);
+  vec_validate_init_empty (im->sw_if_index_to_tap_if_index, sw_if_index, ~0);
+
+  vec_validate_init_empty (im->tap_fd_to_sw_if_index, tap_fd, ~0);
+
+  im->sw_if_index_to_tap_fd[sw_if_index] = tap_fd;
+  im->sw_if_index_to_tap_if_index[sw_if_index] = tap_if_index;
+
+  im->tap_fd_to_sw_if_index[tap_fd] = sw_if_index;
+
+  hash_set (im->tap_if_index_to_sw_if_index, tap_if_index, sw_if_index);
+}
+
+void
+tap_inject_delete_tap (u32 sw_if_index)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+  u32 tap_fd = im->sw_if_index_to_tap_fd[sw_if_index];
+  u32 tap_if_index = im->sw_if_index_to_tap_if_index[sw_if_index];
+
+  im->sw_if_index_to_tap_if_index[sw_if_index] = ~0;
+  im->sw_if_index_to_tap_fd[sw_if_index] = ~0;
+  im->tap_fd_to_sw_if_index[tap_fd] = ~0;
+
+  hash_unset (im->tap_if_index_to_sw_if_index, tap_if_index);
+}
+
+u32
+tap_inject_lookup_tap_fd (u32 sw_if_index)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  vec_validate_init_empty (im->sw_if_index_to_tap_fd, sw_if_index, ~0);
+  return im->sw_if_index_to_tap_fd[sw_if_index];
+}
+
+u32
+tap_inject_lookup_sw_if_index_from_tap_fd (u32 tap_fd)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  vec_validate_init_empty (im->tap_fd_to_sw_if_index, tap_fd, ~0);
+  return im->tap_fd_to_sw_if_index[tap_fd];
+}
+
+u32
+tap_inject_lookup_sw_if_index_from_tap_if_index (u32 tap_if_index)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+  uword * sw_if_index;
+
+  sw_if_index = hash_get (im->tap_if_index_to_sw_if_index, tap_if_index);
+  return sw_if_index ? *(u32 *)sw_if_index : ~0;
+}
+
+
+clib_error_t *
+vlib_plugin_register (vlib_main_t * vm, vnet_plugin_handoff_t * h, int f)
+{
+  return 0;
+}
+
+
+static void
+tap_inject_disable (void)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  im->flags &= ~TAP_INJECT_F_ENABLED;
+
+  clib_warning ("tap-inject is not actually disabled.");
+}
+
+static clib_error_t *
+tap_inject_enable (void)
+{
+  vlib_main_t * vm = vlib_get_main ();
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  if (tap_inject_is_enabled ())
+    return 0;
+
+  tap_inject_enable_netlink ();
+
+  /* Only enable netlink? */
+  if (im->flags & TAP_INJECT_F_CONFIG_NETLINK)
+    {
+      im->flags |= TAP_INJECT_F_ENABLED;
+      return 0;
+    }
+
+  /* Register ARP and ICMP6 as neighbor nodes. */
+  ethernet_register_input_type (vm, ETHERNET_TYPE_ARP, im->neighbor_node_index);
+  ip6_register_protocol (IP_PROTOCOL_ICMP6, im->neighbor_node_index);
+
+  /* Register remaining protocols. */
+  ip4_register_protocol (IP_PROTOCOL_ICMP, im->tx_node_index);
+
+  ip4_register_protocol (IP_PROTOCOL_OSPF, im->tx_node_index);
+  ip4_register_protocol (IP_PROTOCOL_TCP, im->tx_node_index);
+  ip4_register_protocol (IP_PROTOCOL_UDP, im->tx_node_index);
+
+  ip6_register_protocol (IP_PROTOCOL_OSPF, im->tx_node_index);
+  ip6_register_protocol (IP_PROTOCOL_TCP, im->tx_node_index);
+  ip6_register_protocol (IP_PROTOCOL_UDP, im->tx_node_index);
+
+  /* Add IPv4 multicast route. */
+  {
+    ip4_add_del_route_args_t a;
+    ip_adjacency_t add_adj;
+    u32 next_node_index;
+
+    memset (&a, 0, sizeof (a));
+    memset (&add_adj, 0, sizeof (add_adj));
+
+    a.add_adj = &add_adj;
+    a.n_add_adj = 1;
+
+    a.flags = IP4_ROUTE_FLAG_TABLE_ID | IP4_ROUTE_FLAG_ADD;
+    a.table_index_or_table_id = 0;
+    a.dst_address.as_u32 = 0x000000E0; /* 224.0.0.0 */
+    a.dst_address_length = 24;
+    a.adj_index = ~0;
+
+    next_node_index = vlib_node_add_next (vm, ip4_lookup_node.index,
+                                          im->tx_node_index);
+
+    add_adj.explicit_fib_index = ~0;
+    add_adj.rewrite_header.node_index = ip4_rewrite_node.index;
+    add_adj.lookup_next_index = next_node_index;
+    add_adj.if_address_index = ~0;
+
+    ip4_add_del_route (&ip4_main, &a);
+  }
+
+  im->flags |= TAP_INJECT_F_ENABLED;
+
+  return 0;
+}
+
+static uword
+tap_inject_iface_isr (vlib_main_t * vm, vlib_node_runtime_t * node,
+                      vlib_frame_t * f)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+  vnet_hw_interface_t * hw;
+  u32 * hw_if_index;
+  clib_error_t * err = 0;
+
+  vec_foreach (hw_if_index, im->interfaces_to_enable)
+    {
+      hw = vnet_get_hw_interface (vnet_get_main (), *hw_if_index);
+
+      if (hw->hw_class_index == ethernet_hw_interface_class.index)
+        {
+          err = tap_inject_tap_connect (hw);
+          if (err)
+            break;
+        }
+    }
+
+  vec_foreach (hw_if_index, im->interfaces_to_disable)
+    tap_inject_tap_disconnect (*hw_if_index);
+
+  vec_free (im->interfaces_to_enable);
+  vec_free (im->interfaces_to_disable);
+
+  return err ? -1 : 0;
+}
+
+VLIB_REGISTER_NODE (tap_inject_iface_isr_node, static) = {
+  .function = tap_inject_iface_isr,
+  .name = "tap-inject-iface-isr",
+  .type = VLIB_NODE_TYPE_INPUT,
+  .state = VLIB_NODE_STATE_INTERRUPT,
+  .vector_size = sizeof (u32),
+};
+
+
+static clib_error_t *
+tap_inject_interface_add_del (struct vnet_main_t * vnet_main, u32 hw_if_index,
+                              u32 add)
+{
+  vlib_main_t * vm = vlib_get_main ();
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  if (!tap_inject_is_config_enabled ())
+    return 0;
+
+  tap_inject_enable ();
+
+  if (add)
+    vec_add1 (im->interfaces_to_enable, hw_if_index);
+  else
+    vec_add1 (im->interfaces_to_disable, hw_if_index);
+
+  vlib_node_set_interrupt_pending (vm, tap_inject_iface_isr_node.index);
+
+  return 0;
+}
+
+VNET_HW_INTERFACE_ADD_DEL_FUNCTION (tap_inject_interface_add_del);
+
+
+static clib_error_t *
+tap_inject_enable_disable_all_interfaces (int enable)
+{
+  vnet_main_t * vnet_main = vnet_get_main ();
+  tap_inject_main_t * im = tap_inject_get_main ();
+  vnet_hw_interface_t * interfaces;
+  vnet_hw_interface_t * hw;
+  u32 ** indices;
+
+  if (enable)
+    tap_inject_enable ();
+  else
+    tap_inject_disable ();
+
+  /* Collect all the interface indices. */
+  interfaces = vnet_main->interface_main.hw_interfaces;
+  indices = enable ? &im->interfaces_to_enable : &im->interfaces_to_disable;
+  pool_foreach (hw, interfaces, vec_add1 (*indices, hw - interfaces));
+
+  if (tap_inject_iface_isr (vlib_get_main (), 0, 0))
+    return clib_error_return (0, "tap-inject interface add del isr failed");
+
+  return 0;
+}
+
+static clib_error_t *
+tap_inject_cli (vlib_main_t * vm, unformat_input_t * input,
+                 vlib_cli_command_t * cmd)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  if (cmd->function_arg)
+    {
+      clib_error_t * err;
+
+      if (tap_inject_is_config_disabled ())
+        return clib_error_return (0,
+            "tap-inject is disabled in config, thus cannot be enabled.");
+
+      /* Enable */
+      err = tap_inject_enable_disable_all_interfaces (1);
+      if (err)
+        {
+          tap_inject_enable_disable_all_interfaces (0);
+          return err;
+        }
+
+      im->flags |= TAP_INJECT_F_CONFIG_ENABLE;
+    }
+  else
+    {
+      /* Disable */
+      tap_inject_enable_disable_all_interfaces (0);
+      im->flags &= ~TAP_INJECT_F_CONFIG_ENABLE;
+    }
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (tap_inject_enable_cmd, static) = {
+  .path = "enable tap-inject",
+  .short_help = "enable tap-inject",
+  .function = tap_inject_cli,
+  .function_arg = 1,
+};
+
+VLIB_CLI_COMMAND (tap_inject_disable_cmd, static) = {
+  .path = "disable tap-inject",
+  .short_help = "disable tap-inject",
+  .function = tap_inject_cli,
+  .function_arg = 0,
+};
+
+
+static clib_error_t *
+show_tap_inject (vlib_main_t * vm, unformat_input_t * input,
+                 vlib_cli_command_t * cmd)
+{
+  vnet_main_t * vnet_main = vnet_get_main ();
+  tap_inject_main_t * im = tap_inject_get_main ();
+  u32 k, v;
+
+  if (tap_inject_is_config_disabled ())
+    {
+      vlib_cli_output (vm, "tap-inject is disabled in config.\n");
+      return 0;
+    }
+
+  if (!tap_inject_is_enabled ())
+    {
+      vlib_cli_output (vm, "tap-inject is not enabled.\n");
+      return 0;
+    }
+
+  hash_foreach (k, v, im->tap_if_index_to_sw_if_index, {
+    vlib_cli_output (vm, "%U -> %U",
+            format_vnet_sw_interface_name, vnet_main,
+            vnet_get_sw_interface (vnet_main, v),
+            format_tap_inject_tap_name, k);
+  });
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (show_tap_inject_cmd, static) = {
+  .path = "show tap-inject",
+  .short_help = "show tap-inject",
+  .function = show_tap_inject,
+};
+
+
+static clib_error_t *
+tap_inject_config (vlib_main_t * vm, unformat_input_t * input)
+{
+  tap_inject_main_t * im = tap_inject_get_main ();
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "enable"))
+        im->flags |= TAP_INJECT_F_CONFIG_ENABLE;
+
+      else if (unformat (input, "disable"))
+        im->flags |= TAP_INJECT_F_CONFIG_DISABLE;
+
+      else if (unformat (input, "netlink-only"))
+        im->flags |= TAP_INJECT_F_CONFIG_NETLINK;
+
+      else
+        return clib_error_return (0, "syntax error `%U'",
+                                  format_unformat_error, input);
+    }
+
+  if (tap_inject_is_config_enabled () && tap_inject_is_config_disabled ())
+    return clib_error_return (0,
+              "tap-inject cannot be both enabled and disabled.");
+
+  return 0;
+}
+
+VLIB_CONFIG_FUNCTION (tap_inject_config, "tap-inject");