/****************************************************************************
 * net/neighbor/neighbor_lookup.c
 *
 *   Copyright (C) 2007-2009, 2015 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * A leverage of logic from uIP which also has a BSD style license
 *
 *   Copyright (c) 2006, Swedish Institute of Computer Science.  All rights
 *     reserved.
 *   Author: Adam Dunkels <adam@sics.se>
 *
 * 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 of the Institute 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 INSTITUTE 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 INSTITUTE 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 <errno.h>
#include <debug.h>
#include <string.h>

#include <nuttx/net/ip.h>

#include "netdev/netdev.h"
#include "neighbor/neighbor.h"

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct neighbor_table_info_s
{
  net_ipv6addr_t              ni_ipaddr; /* IPv6 address for lookup */
  FAR struct neighbor_addr_s *ni_laddr;  /* Location to return the link
                                          * layer address */
};

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

/****************************************************************************
 * Name: neighbor_match
 *
 * Description:
 *   This is a callback that checks if the network device has the
 *   indicated IPv6 address assigned to it.
 *
 ****************************************************************************/

static int neighbor_match(FAR struct net_driver_s *dev, FAR void *arg)
{
  FAR struct neighbor_table_info_s *info = arg;

  /* Check if the network device has been assigned the IP address of the
   * lookup.
   */

  if (!net_ipv6addr_cmp(dev->d_ipv6addr, info->ni_ipaddr))
    {
      return 0;
    }

  /* Yes.. Return the matching link layer address if the caller of
   * neighbor_lookup() provided a non-NULL location.
   */

  if (info->ni_laddr != NULL)
    {
      info->ni_laddr->na_lltype = dev->d_lltype;
      info->ni_laddr->na_llsize = netdev_lladdrsize(dev);
      memcpy(&info->ni_laddr->u, &dev->d_mac, info->ni_laddr->na_llsize);
    }

  /* Return success in any event */

  return 1;
}

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

/****************************************************************************
 * Name:  neighbor_lookup
 *
 * Description:
 *   Find an entry in the Neighbor Table and return its link layer address.
 *
 * Input Parameters:
 *   ipaddr - The IPv6 address to use in the lookup;
 *   laddr  - Location to return the corresponding link layer address.
 *            This address may be NULL.  In that case, this function may be
 *            used simply to determine if the link layer address is available.
 *
 * Returned Value:
 *   Zero (OK) if the link layer address is returned.  A negated errno value
 *   is returned on any error.
 *
 ****************************************************************************/

int neighbor_lookup(FAR const net_ipv6addr_t ipaddr,
                    FAR struct neighbor_addr_s *laddr)
{
  FAR struct neighbor_entry *neighbor;
  struct neighbor_table_info_s info;

  /* Check if the IPv6 address is already in the neighbor table. */

  neighbor = neighbor_findentry(ipaddr);
  if (neighbor != NULL)
    {
      /* Yes.. return the link layer address if the caller has provided a
       * non-NULL address in 'laddr'.
       */

      if (laddr != NULL)
        {
          memcpy(laddr, &neighbor->ne_addr, sizeof(*laddr));
        }

      /* Return success in any case meaning that a valid link layer
       * address mapping is available for the IPv6 address.
       */

      return OK;
    }

  /* No.. check if the IPv6 address is the address assigned to a local
   * network device.  If so, return a mapping of that IPv6 address
   * to the linker layer address assigned to the network device.
   */

  net_ipv6addr_copy(info.ni_ipaddr, ipaddr);
  info.ni_laddr = laddr;

  if (netdev_foreach(neighbor_match, &info) != 0)
    {
      return OK;
    }

  /* Not found */

  return -ENOENT;
}