/*
 * 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"

#include <vnet/mfib/mfib_table.h>
#include <vnet/ip/ip.h>
#include <vnet/ip/lookup.h>
#include <vnet/fib/fib.h>
#include <vnet/osi/osi.h>

static tap_inject_main_t tap_inject_main;
extern dpo_type_t tap_inject_dpo_type;

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;
}

/* *INDENT-OFF* */
VLIB_PLUGIN_REGISTER () = {
    // .version = VPP_BUILD_VER, FIXME
    .description = "router",
};
/* *INDENT-ON* */


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);
  /* Registering ISIS to OSI node. */
  osi_register_input_protocol (OSI_PROTOCOL_isis, im->tx_node_index);

  {
    dpo_id_t dpo = DPO_INVALID;

    const mfib_prefix_t pfx_224_0_0_0 = {
        .fp_len = 24,
        .fp_proto = FIB_PROTOCOL_IP4,
        .fp_grp_addr = {
            .ip4.as_u32 = clib_host_to_net_u32(0xe0000000),
        },
        .fp_src_addr = {
            .ip4.as_u32 = 0,
        },
    };

    dpo_set(&dpo, tap_inject_dpo_type, DPO_PROTO_IP4, ~0);

    index_t repi = replicate_create(1, DPO_PROTO_IP4);
    replicate_set_bucket(repi, 0, &dpo);

    mfib_table_entry_special_add(0,
                                 &pfx_224_0_0_0,
                                 MFIB_SOURCE_API,
                                 MFIB_ENTRY_FLAG_ACCEPT_ALL_ITF,
                                 repi);

    dpo_reset(&dpo);
  }

  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");