/*
 *------------------------------------------------------------------
 * Copyright (c) 2017 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/plugin/plugin.h>
#include <vpp/app/version.h>
#include <vnet/ip/ip.h>
#include <vnet/mfib/mfib_entry.h>
#include <vlib/unix/unix.h>
#include <vnet/adj/adj_mcast.h>
#include <vnet/fib/fib_entry.h>
#include <vnet/fib/fib_table.h>
#include <vnet/mfib/mfib_table.h>

#include <igmp/igmp.h>
#include <igmp/igmp_format.h>
#include <igmp/igmp_pkt.h>

#include <limits.h>
#include <float.h>

igmp_main_t igmp_main;

/* General Query address */
const static mfib_prefix_t mpfx_general_query = {
  .fp_proto = FIB_PROTOCOL_IP4,
  .fp_len = 32,
  .fp_grp_addr = {
    .ip4 = {
      .as_u32 = IGMP_GENERAL_QUERY_ADDRESS,
    },
  },
};

/* Report address */
const static mfib_prefix_t mpfx_report = {
  .fp_proto = FIB_PROTOCOL_IP4,
  .fp_len = 32,
  .fp_grp_addr = {
    .ip4 = {
      .as_u32 = IGMP_MEMBERSHIP_REPORT_ADDRESS,
    },
  },
};

/**
 * @brief igmp send query (igmp_timer_function_t)
 *
 *   Send an igmp query.
 *   If the timer holds group key, send Group-Specific query,
 *   else send General query.
 */
static void
igmp_send_general_query (u32 obj, void *dat)
{
  igmp_pkt_build_query_t bq;
  igmp_config_t *config;

  config = igmp_config_get (obj);

  IGMP_DBG ("send-general-query: %U",
	    format_vnet_sw_if_index_name, vnet_get_main (),
	    config->sw_if_index);

  igmp_timer_retire (&config->timers[IGMP_CONFIG_TIMER_GENERAL_QUERY]);

  igmp_pkt_build_query_init (&bq, config->sw_if_index);
  igmp_pkt_query_v3_add_group (&bq, NULL, NULL);
  igmp_pkt_query_v3_send (&bq);

  /*
   * re-schedule
   */
  config->timers[IGMP_CONFIG_TIMER_GENERAL_QUERY] =
    igmp_timer_schedule (igmp_timer_type_get (IGMP_TIMER_QUERY),
			 igmp_config_index (config),
			 igmp_send_general_query, NULL);
}

static void
igmp_send_state_change_group_report_v3 (u32 sw_if_index,
					const igmp_group_t * group)
{
  igmp_pkt_build_report_t br;

  IGMP_DBG ("state-change-group: %U", format_igmp_key, group->key);

  igmp_pkt_build_report_init (&br, sw_if_index);
  igmp_pkt_report_v3_add_group (&br,
				group,
				IGMP_MEMBERSHIP_GROUP_allow_new_sources);
  igmp_pkt_report_v3_send (&br);
}

static void
igmp_resend_state_change_group_report_v3 (u32 gi, void *data)
{
  igmp_config_t *config;
  igmp_group_t *group;

  group = igmp_group_get (gi);
  config = igmp_config_get (group->config);

  igmp_timer_retire (&group->timers[IGMP_GROUP_TIMER_RESEND_REPORT]);
  igmp_send_state_change_group_report_v3 (config->sw_if_index, group);

  if (++group->n_reports_sent < config->robustness_var)
    {
      group->timers[IGMP_GROUP_TIMER_RESEND_REPORT] =
	igmp_timer_schedule (igmp_timer_type_get (IGMP_TIMER_REPORT_INTERVAL),
			     igmp_group_index (group),
			     igmp_resend_state_change_group_report_v3, NULL);
    }
}

int
igmp_listen (vlib_main_t * vm,
	     igmp_filter_mode_t mode,
	     u32 sw_if_index,
	     const ip46_address_t * saddrs, const ip46_address_t * gaddr)
{
  const ip46_address_t *saddr;
  igmp_config_t *config;
  igmp_group_t *group;

  /*
   * RFC 3376 Section 2
   " For a given combination of socket, interface, and multicast address,
   * only a single filter mode and source list can be in effect at any one
   * time.  However, either the filter mode or the source list, or both,
   * may be changed by subsequent IPMulticastListen requests that specify
   * the same socket, interface, and multicast address.  Each subsequent
   * request completely replaces any earlier request for the given socket,
   * interface and multicast address."
   */
  int rv = 0;
  IGMP_DBG ("listen: (%U, %U) %U %U",
	    format_igmp_src_addr_list, saddrs,
	    format_igmp_key, gaddr,
	    format_vnet_sw_if_index_name, vnet_get_main (),
	    sw_if_index, format_igmp_filter_mode, mode);
  /*
   * find configuration, if it doesn't exist, then this interface is
   * not IGMP enabled
   */
  config = igmp_config_lookup (sw_if_index);

  if (!config)
    {
      rv = VNET_API_ERROR_INVALID_INTERFACE;
      goto error;
    }
  if (config->mode != IGMP_MODE_HOST)
    {
      rv = VNET_API_ERROR_INVALID_INTERFACE;
      goto error;
    }

  /* find igmp group, if it doesn't exist, create new */
  group = igmp_group_lookup (config, gaddr);

  if (!group)
    {
      group = igmp_group_alloc (config, gaddr, mode);

      /* new group implies create all sources */
      vec_foreach (saddr, saddrs)
      {
	igmp_group_src_update (group, saddr, IGMP_MODE_HOST);
      }

      /*
       * Send state changed event report for the group.
       *
       * RFC3376 Section 5.1
       *  "To cover the possibility of the State-Change Report being missed by
       *   one or more multicast routers, it is retransmitted [Robustness
       *   Variable] - 1 more times, at intervals chosen at random from the
       *   range (0, [Unsolicited Report Interval])."
       */
      igmp_send_state_change_group_report_v3 (config->sw_if_index, group);

      igmp_timer_retire (&group->timers[IGMP_GROUP_TIMER_RESEND_REPORT]);

      group->n_reports_sent = 1;
      group->timers[IGMP_GROUP_TIMER_RESEND_REPORT] =
	igmp_timer_schedule (igmp_timer_type_get (IGMP_TIMER_REPORT_INTERVAL),
			     igmp_group_index (group),
			     igmp_resend_state_change_group_report_v3, NULL);
    }
  else
    {
      IGMP_DBG ("... update (%U, %U) %U %U",
		format_igmp_src_addr_list, saddrs,
		format_igmp_key, gaddr,
		format_vnet_sw_if_index_name, vnet_get_main (),
		sw_if_index, format_igmp_filter_mode, mode);

      /*
       * RFC 3367 Section 5.1
       *
       *   Old State         New State         State-Change Record Sent
       *   ---------         ---------         ------------------------
       *
       * 1) INCLUDE (A)       INCLUDE (B)       ALLOW (B-A), BLOCK (A-B)
       * 2) EXCLUDE (A)       EXCLUDE (B)       ALLOW (A-B), BLOCK (B-A)
       * 3) INCLUDE (A)       EXCLUDE (B)       TO_EX (B)
       * 4) EXCLUDE (A)       INCLUDE (B)       TO_IN (B)
       *
       * N.B. We do not split state-change records for pending transfer
       * hence there is no merge logic required.
       */

      if (IGMP_FILTER_MODE_INCLUDE == mode)
	{
	  ip46_address_t *added, *removed;
	  igmp_pkt_build_report_t br;

	  /*
	   * find the list of sources that have been added and removed from
	   * the include set
	   */
	  removed =
	    igmp_group_present_minus_new (group, IGMP_FILTER_MODE_INCLUDE,
					  saddrs);
	  added =
	    igmp_group_new_minus_present (group, IGMP_FILTER_MODE_INCLUDE,
					  saddrs);

	  if (!(vec_len (added) || vec_len (removed)))
	    /* no change => done */
	    goto error;

	  igmp_pkt_build_report_init (&br, config->sw_if_index);

	  if (vec_len (added))
	    {
	      igmp_pkt_report_v3_add_report (&br,
					     group->key,
					     added,
					     IGMP_MEMBERSHIP_GROUP_allow_new_sources);
	    }

	  if (vec_len (removed))
	    {
	      igmp_pkt_report_v3_add_report (&br,
					     group->key,
					     removed,
					     IGMP_MEMBERSHIP_GROUP_block_old_sources);
	    }

	  IGMP_DBG ("... added %U", format_igmp_src_addr_list, added);
	  IGMP_DBG ("... removed %U", format_igmp_src_addr_list, removed);

	  igmp_pkt_report_v3_send (&br);

	  /*
	   * clear the group of the old sources and populate it with the new
	   * set requested
	   */
	  igmp_group_free_all_srcs (group);

	  vec_foreach (saddr, saddrs)
	  {
	    igmp_group_src_update (group, saddr, IGMP_MODE_HOST);
	  }

	  if (0 == igmp_group_n_srcs (group, mode))
	    igmp_group_clear (&group);

	  vec_free (added);
	  vec_free (removed);
	}
      else
	{
	  /*
	   * The control plane is excluding some sources.
	   *  - First; check for those that are present in the include list
	   *  - Second; check add them to the exclude list
	   *
	   * TODO
	   */
	}
    }

error:
  return (rv);
}

static walk_rc_t
igmp_sw_if_down (vnet_main_t * vnm, u32 sw_if_index, void *ctx)
{
  igmp_config_t *config;
  config = igmp_config_lookup (sw_if_index);
  IGMP_DBG ("down: %U",
	    format_vnet_sw_if_index_name, vnet_get_main (), sw_if_index);
  if (NULL != config)
    {
      igmp_clear_config (config);
    }

  return (WALK_CONTINUE);
}

/** \brief igmp hardware interface link up down
    @param vnm - vnet main
    @param hw_if_index - interface hw_if_index
    @param flags - hw interface flags

    If an interface goes down, remove its (S,G)s.
*/
static clib_error_t *
igmp_hw_interface_link_up_down (vnet_main_t * vnm, u32 hw_if_index, u32 flags)
{
  clib_error_t *error = NULL;
  /* remove igmp state from down interfaces */
  if (!(flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
    vnet_hw_interface_walk_sw (vnm, hw_if_index, igmp_sw_if_down, NULL);
  return error;
}

VNET_HW_INTERFACE_LINK_UP_DOWN_FUNCTION (igmp_hw_interface_link_up_down);
int
igmp_enable_disable (u32 sw_if_index, u8 enable, igmp_mode_t mode)
{
  igmp_config_t *config;
  igmp_main_t *im = &igmp_main;
  u32 mfib_index;
  IGMP_DBG ("%s:  %U", (enable ? "Enabled" : "Disabled"),
	    format_vnet_sw_if_index_name, vnet_get_main (), sw_if_index);

  fib_route_path_t via_itf_path =
    {
      .frp_proto = fib_proto_to_dpo (FIB_PROTOCOL_IP4),
      .frp_addr = zero_addr,
      .frp_sw_if_index = sw_if_index,
      .frp_fib_index = 0,
      .frp_weight = 1,
    .frp_mitf_flags = MFIB_ITF_FLAG_ACCEPT,
    };
  fib_route_path_t for_us_path = {
    .frp_proto = fib_proto_to_dpo (FIB_PROTOCOL_IP4),
    .frp_addr = zero_addr,
    .frp_sw_if_index = 0xffffffff,
    .frp_fib_index = 1,
    .frp_weight = 0,
    .frp_flags = FIB_ROUTE_PATH_LOCAL,
    .frp_mitf_flags = MFIB_ITF_FLAG_FORWARD,
  };

  /* find configuration, if it doesn't exist, create new */
  config = igmp_config_lookup (sw_if_index);
  mfib_index = mfib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
						     sw_if_index);
  if (!config && enable)
    {
      u32 ii;

      vec_validate_init_empty (im->igmp_config_by_sw_if_index,
			       sw_if_index, ~0);
      pool_get (im->configs, config);
      clib_memset (config, 0, sizeof (igmp_config_t));
      config->sw_if_index = sw_if_index;
      config->igmp_group_by_key =
	hash_create_mem (0, sizeof (igmp_key_t), sizeof (uword));
      config->robustness_var = IGMP_DEFAULT_ROBUSTNESS_VARIABLE;
      config->mode = mode;
      config->proxy_device_id = ~0;

      for (ii = 0; ii < IGMP_CONFIG_N_TIMERS; ii++)
	config->timers[ii] = IGMP_TIMER_ID_INVALID;

      if (IGMP_MODE_ROUTER == mode)
	{
	  config->timers[IGMP_CONFIG_TIMER_GENERAL_QUERY] =
	    igmp_timer_schedule (igmp_timer_type_get (IGMP_TIMER_QUERY),
				 igmp_config_index (config),
				 igmp_send_general_query, NULL);
	}

      config->adj_index =
	adj_mcast_add_or_lock (FIB_PROTOCOL_IP4, VNET_LINK_IP4,
			       config->sw_if_index);
      im->igmp_config_by_sw_if_index[config->sw_if_index] =
	(config - im->configs);
      {
	vec_validate (im->n_configs_per_mfib_index, mfib_index);
	im->n_configs_per_mfib_index[mfib_index]++;
	if (1 == im->n_configs_per_mfib_index[mfib_index])
	  {
	    /* first config in this FIB */
	    mfib_table_lock (mfib_index, FIB_PROTOCOL_IP4, MFIB_SOURCE_IGMP);
	    mfib_table_entry_path_update (mfib_index, &mpfx_general_query,
					  MFIB_SOURCE_IGMP,
					  MFIB_ENTRY_FLAG_NONE, &for_us_path);
	    mfib_table_entry_path_update (mfib_index, &mpfx_report,
					  MFIB_SOURCE_IGMP,
					  MFIB_ENTRY_FLAG_NONE, &for_us_path);
	  }
	mfib_table_entry_path_update (mfib_index, &mpfx_general_query,
				      MFIB_SOURCE_IGMP, MFIB_ENTRY_FLAG_NONE,
				      &via_itf_path);
	mfib_table_entry_path_update (mfib_index, &mpfx_report,
				      MFIB_SOURCE_IGMP, MFIB_ENTRY_FLAG_NONE,
				      &via_itf_path);
      }
    }
  else if (config && !enable)
    {
      vec_validate (im->n_configs_per_mfib_index, mfib_index);
      im->n_configs_per_mfib_index[mfib_index]--;
      if (0 == im->n_configs_per_mfib_index[mfib_index])
	{
	  /* last config in this FIB */
	  mfib_table_entry_path_remove (mfib_index,
					&mpfx_general_query,
					MFIB_SOURCE_IGMP, &for_us_path);
	  mfib_table_entry_path_remove (mfib_index,
					&mpfx_report,
					MFIB_SOURCE_IGMP, &for_us_path);
	  mfib_table_unlock (mfib_index, FIB_PROTOCOL_IP4, MFIB_SOURCE_IGMP);
	}

      mfib_table_entry_path_remove (mfib_index,
				    &mpfx_general_query,
				    MFIB_SOURCE_IGMP, &via_itf_path);
      mfib_table_entry_path_remove (mfib_index,
				    &mpfx_report,
				    MFIB_SOURCE_IGMP, &via_itf_path);

      /*
       * remove interface from proxy device
       * if this device is upstream, delete proxy device
       */
      if (config->mode == IGMP_MODE_ROUTER)
	igmp_proxy_device_add_del_interface (config->proxy_device_id,
					     config->sw_if_index, 0);
      else if (config->mode == IGMP_MODE_HOST)
	igmp_proxy_device_add_del (config->proxy_device_id,
				   config->sw_if_index, 0);

      igmp_clear_config (config);
      im->igmp_config_by_sw_if_index[config->sw_if_index] = ~0;
      hash_free (config->igmp_group_by_key);
      pool_put (im->configs, config);
    }
  else
    {
      return -1;
    }

  return (0);
}

/** \brief igmp initialization
    @param vm - vlib main

    initialize igmp plugin. Initialize igmp_main, set mfib to allow igmp traffic.
*/
static clib_error_t *
igmp_init (vlib_main_t * vm)
{
  igmp_main_t *im = &igmp_main;

  im->igmp_api_client_by_client_index = hash_create (0, sizeof (u32));
  im->logger = vlib_log_register_class ("igmp", 0);

  IGMP_DBG ("initialized");

  return (0);
}

VLIB_INIT_FUNCTION (igmp_init) =
{
  .runs_after = VLIB_INITS("ip4_lookup_init"),
};
VLIB_PLUGIN_REGISTER () =
{
  .version = VPP_BUILD_VER,
  .description = "Internet Group Management Protocol (IGMP)",
};

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */