/****************************************************************************
 * net/route/net_router.c
 *
 *   Copyright (C) 2013-2015, 2017 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <string.h>
#include <errno.h>

#include <netinet/in.h>

#include <nuttx/net/ip.h>

#include "devif/devif.h"
#include "route/cacheroute.h"
#include "route/route.h"

#if defined(CONFIG_NET) && defined(CONFIG_NET_ROUTE)

/****************************************************************************
 * Pre-processor defintions
 ****************************************************************************/

#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
#  define IPv4_ROUTER entry.router
#else
#  define IPv4_ROUTER router
#endif

#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
#  define IPv6_ROUTER entry.router
#else
#  define IPv6_ROUTER router
#endif

/****************************************************************************
 * Public Types
 ****************************************************************************/

#ifdef CONFIG_NET_IPv4
struct route_ipv4_match_s
{
  in_addr_t target;              /* Target IPv4 address on remote network */
#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
  struct net_route_ipv4_s entry; /* Full entry from the IPv4 routing table */
#else
  in_addr_t router;              /* IPv4 address of router a local networks */
#endif
};
#endif

#ifdef CONFIG_NET_IPv6
struct route_ipv6_match_s
{
  net_ipv6addr_t target;         /* Target IPv6 address on remote network */
#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
  struct net_route_ipv6_s entry; /* Full entry from the IPv6 routing table */
#else
  net_ipv6addr_t router;         /* IPv6 address of router a local networks */
#endif
};
#endif

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: net_ipv4_match
 *
 * Description:
 *   Return 1 if the IPv4 route is available
 *
 * Input Parameters:
 *   route - The next route to examine
 *   arg   - The match values (cast to void*)
 *
 * Returned Value:
 *   0 if the entry is not a match; 1 if the entry matched and was cleared.
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv4
static int net_ipv4_match(FAR struct net_route_ipv4_s *route, FAR void *arg)
{
  FAR struct route_ipv4_match_s *match = (FAR struct route_ipv4_match_s *)arg;

  /* To match, the masked target addresses must be the same.  In the event
   * of multiple matches, only the first is returned.  There is not (yet) any
   * concept for the precedence of networks.
   */

  if (net_ipv4addr_maskcmp(route->target, match->target, route->netmask))
    {
#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
      /* They match.. Copy the entire routing table entry */

      memcpy(&match->entry, route, sizeof(struct net_route_ipv4_s));
#else
      /* They match.. Copy the router address */

      net_ipv4addr_copy(match->router, route->router);
#endif
      return 1;
    }

  return 0;
}
#endif /* CONFIG_NET_IPv4 */

/****************************************************************************
 * Name: net_ipv6_match
 *
 * Description:
 *   Return 1 if the IPv6 route is available
 *
 * Input Parameters:
 *   route - The next route to examine
 *   arg   - The match values (cast to void*)
 *
 * Returned Value:
 *   0 if the entry is not a match; 1 if the entry matched and was cleared.
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv6
static int net_ipv6_match(FAR struct net_route_ipv6_s *route, FAR void *arg)
{
  FAR struct route_ipv6_match_s *match = (FAR struct route_ipv6_match_s *)arg;

  /* To match, the masked target addresses must be the same.  In the event
   * of multiple matches, only the first is returned.  There is not (yet) any
   * concept for the precedence of networks.
   */

  if (net_ipv6addr_maskcmp(route->target, match->target, route->netmask))
    {
#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
      /* They match.. Copy the entire routing table entry */

      memcpy(&match->entry, route, sizeof(struct net_route_ipv6_s));
#else
      /* They match.. Copy the router address */

      net_ipv6addr_copy(match->router, route->router);
#endif
      return 1;
    }

  return 0;
}
#endif /* CONFIG_NET_IPv6 */

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: net_ipv4_router
 *
 * Description:
 *   Given an IPv4 address on a external network, return the address of the
 *   router on a local network that can forward to the external network.
 *
 * Input Parameters:
 *   target - An IPv4 address on a remote network to use in the lookup.
 *   router - The address of router on a local network that can forward our
 *     packets to the target.
 *
 * Returned Value:
 *   OK on success; Negated errno on failure.
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv4
int net_ipv4_router(in_addr_t target, FAR in_addr_t *router)
{
  struct route_ipv4_match_s match;
  int ret;

  /* Do not route the special broadcast IP address */

  if (net_ipv4addr_cmp(target, INADDR_BROADCAST))
    {
      return -ENOENT;
    }

  /* Set up the comparison structure */

  memset(&match, 0, sizeof(struct route_ipv4_match_s));
  net_ipv4addr_copy(match.target, target);

#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
  /* First see if we can find a router entry in the cache */

  ret = net_foreachcache_ipv4(net_ipv4_match, &match);
  if (ret <= 0)
#endif
    {
      /* Not found in the cache.  Try to find a router entry with the
       * routing table that can forward to this address
       */

      ret = net_foreachroute_ipv4(net_ipv4_match, &match);
    }

  /* Did we find a route? */

  if (ret <= 0)
    {
      /* No.. there is no route for this address */

      return -ENOENT;
    }

  /* We found a route. */

#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
  /* Add the route to the cache.  If the route is already in the cache, this
   * will update it to the most recently accessed.
   */

  (void)net_addcache_ipv4(&match.entry);
#endif

  /* Return the router address. */

  net_ipv4addr_copy(*router, match.IPv4_ROUTER);
  return OK;
}
#endif /* CONFIG_NET_IPv4 */

/****************************************************************************
 * Name: net_ipv6_router
 *
 * Description:
 *   Given an IPv6 address on a external network, return the address of the
 *   router on a local network that can forward to the external network.
 *
 * Input Parameters:
 *   target - An IPv6 address on a remote network to use in the lookup.
 *   router - The address of router on a local network that can forward our
 *     packets to the target.
 *
 * Returned Value:
 *   OK on success; Negated errno on failure.
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv6
int net_ipv6_router(const net_ipv6addr_t target, net_ipv6addr_t router)
{
  struct route_ipv6_match_s match;
  int ret;

  /* Do not route to any the special IPv6 multicast addresses */

  if (target[0] == HTONS(0xff02))
    {
      return -ENOENT;
    }

  /* Set up the comparison structure */

  memset(&match, 0, sizeof(struct route_ipv6_match_s));
  net_ipv6addr_copy(match.target, target);

#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
  /* First see if we can find a router entry in the cache */

  ret = net_foreachcache_ipv6(net_ipv6_match, &match);
  if (ret <= 0)
#endif
    {
      /* Not found in the cache.  Try to find a router entry with the
       * routing table that can forward to this address
       */

      ret = net_foreachroute_ipv6(net_ipv6_match, &match);
    }

  /* Did we find a route? */

  if (ret <= 0)
    {
      /* No.. there is no route for this address */

      return -ENOENT;
    }

  /* We found a route. */

#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
  /* Add the route to the cache.  If the route is already in the cache, this
   * will update it to the most recently accessed.
   */

  (void)net_addcache_ipv6(&match.entry);
#endif

  /* Return the router address. */

  net_ipv6addr_copy(router, match.IPv6_ROUTER);
  return OK;
}
#endif /* CONFIG_NET_IPv6 */

#endif /* CONFIG_NET && CONFIG_NET_ROUTE */