/****************************************************************************
 * apps/netutils/netlib/netlib_obtainipv6addr.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you 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.
 *
 ****************************************************************************/

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

#include <nuttx/config.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <debug.h>

#include <netinet/in.h>
#include <net/if.h>
#include <nuttx/net/dns.h>

#include "netutils/netlib.h"
#include "netutils/dhcp6c.h"

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

#ifdef CONFIG_NET_ETHERNET
static void icmpv6_linkipaddr_6(FAR const uint8_t *mac, FAR uint16_t *ipaddr)
{
  ipaddr[0]  = htons(0xfe80);
  ipaddr[1]  = 0;
  ipaddr[2]  = 0;
  ipaddr[3]  = 0;
  ipaddr[4]  = htons(mac[0] << 8 | mac[1]);
  ipaddr[5]  = htons(mac[2] << 8 | 0x00ff);
  ipaddr[6]  = htons(0x00fe << 8 | mac[3]);
  ipaddr[7]  = htons(mac[4] << 8 | mac[5]);
  ipaddr[4] ^= htons(0x0200);
}

static void dhcpv6_set_lladdr(FAR const char *ifname)
{
  struct in6_addr addr6;
  uint8_t mac[IFHWADDRLEN];

  /* Get the MAC address of the NIC */

  netlib_getmacaddr(ifname, mac);

  /* Set the Link Local Address of the NIC */

  icmpv6_linkipaddr_6(mac, (uint16_t *)&addr6);
  netlib_set_ipv6addr(ifname, &addr6);
  netlib_prefix2ipv6netmask(64, &addr6);
}
#endif

static int dhcpv6_setup_result(FAR const char *ifname,
                               FAR struct dhcp6c_state *presult)
{
  int ret;

  ret = netlib_set_ipv6addr(ifname, &presult->addr);
  if (ret != OK)
    {
      nerr("netlib_set_ipv6addr fail\n");
      return ret;
    }

  ret = netlib_set_ipv6netmask(ifname, &presult->netmask);
  if (ret != OK)
    {
      nerr("netlib_set_ipv6netmask fail\n");
      return ret;
    }

#if defined(CONFIG_NET_IPv6) && defined(CONFIG_NETDB_DNSCLIENT)
  ret = netlib_set_ipv6dnsaddr(&presult->dns);
  if (ret != OK)
    {
      nerr("netlib_set_ipv6dnsaddr fail\n");
      return ret;
    }
#endif

  return ret;
}

static int dhcpv6_obtain_statefuladdr(FAR const char *ifname)
{
  FAR void *handle = NULL;
  struct dhcp6c_state result;
  int ret;

  memset(&result, 0, sizeof(result));
#ifdef CONFIG_NET_ETHERNET
  dhcpv6_set_lladdr(ifname);
#endif
  handle = dhcp6c_open(ifname);

  ret = dhcp6c_request(handle, &result);
  if (ret == OK)
    {
      dhcpv6_setup_result(ifname, &result);
    }
  else
    {
      nerr("dhcp6c_request fail\n");
    }

  dhcp6c_close(handle);
  return ret;
}

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

/****************************************************************************
 * Name: netlib_obtain_ipv6addr
 *
 * Description:
 *   Perform ICMPv6 auto-configuration and DHCPv6 in an attempt to
 *   get the IP address of the specified network device.
 *
 * Parameters:
 *   ifname   The name of the interface
 *
 * Return:
 *   0 on success; negative integer on failure
 *
 ****************************************************************************/

int netlib_obtain_ipv6addr(FAR const char *ifname)
{
  int ret;

  if (ifname == NULL)
    {
      /* No interface name */

      errno = EINVAL;
      return ERROR;
    }

  ret = netlib_icmpv6_autoconfiguration(ifname);
  if (ret)
    {
      if (errno == EADDRNOTAVAIL)
        {
          ninfo("obtain IPv6 address by dhcpv6\n");
          ret = dhcpv6_obtain_statefuladdr(ifname);
        }
      else
        {
          nerr("netlib_icmpv6_autoconfiguration fail\n");
        }
    }

  return ret;
}