/****************************************************************************
 * net/sixlowpan/sixlowpan_utils.c
 *
 *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 *   Copyright (C) 2017, Gregory Nutt, all rights reserved
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Derives from logic in Contiki:
 *
 *   Copyright (c) 2008, Swedish Institute of Computer Science.
 *   All rights reserved.
 *   Authors: Adam Dunkels <adam@sics.se>
 *            Nicolas Tsiftes <nvt@sics.se>
 *            Niclas Finne <nfi@sics.se>
 *            Mathilde Durvy <mdurvy@cisco.com>
 *            Julien Abeille <jabeille@cisco.com>
 *            Joakim Eriksson <joakime@sics.se>
 *            Joel Hoglund <joel@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.
 *
 ****************************************************************************/

/* Frame Organization.  The IOB data is retained in the io_data[] field of the
 * IOB structure like:
 *
 *     Content            Offset
 *   +------------------+ 0
 *   | Frame Header     |
 *   +------------------+ g_dataoffset
 *   | Procotol Headers |
 *   | Data Payload     |
 *   +------------------+ iob->io_len
 *   | Unused           |
 *   +------------------+ CONFIG_NET_6LOWPAN_FRAMELEN
 */

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

#include <nuttx/config.h>

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

#include <nuttx/net/sixlowpan.h>

#include "sixlowpan/sixlowpan_internal.h"

#ifdef CONFIG_NET_6LOWPAN

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

/****************************************************************************
 * Name: sixlowpan_frame_hdralloc
 *
 * Description:
 *   Allocate space for a header within the packet buffer (dev->d_buf).
 *
 ****************************************************************************/

int sixlowpan_frame_hdralloc(FAR struct iob_s *iob, int size)
{
  if (size <= FRAME_REMAINING(iob))
    {
      g_dataoffset += size;
      iob->io_len  += size;
      return OK;
    }

  return -ENOMEM;
}

/****************************************************************************
 * Name: sixlowpan_ipfromrime
 *
 * Description:
 *   Use stateless auto-configuration to create an IP address from a rime
 *   address:
 *
 *    128  112  96   80    64   48   32   16
 *    ---- ---- ---- ----  ---- ---- ---- ----
 *    fe80 0000 0000 0000  xxxx xxxx 0000 0000 2-byte Rime address (VALID?)
 *    fe80 0000 0000 0000  xxxx xxxx xxxx xxxx 8-byte Rime address
 *
 ****************************************************************************/

void sixlowpan_ipfromrime(FAR const struct rimeaddr_s *rime,
                          net_ipv6addr_t ipaddr)
{
  memset(ipaddr, 0, sizeof(net_ipv6addr_t));
  ipaddr[0] = 0xfe80;

  /* We consider only links with IEEE EUI-64 identifier or IEEE 48-bit MAC
   * addresses.  NOTE: that CONFIG_NET_6LOWPAN_RIMEADDR_SIZE may be 2 or
   * 8.  In the case of 2, we treat the address like an 8 byte address with
   * the lower bytes set to zero.
   *
   * REVISIT:  This is just a guess so that I can continue making forward
   * progress.  What is the correct policy?
   */

  memcpy(&ipaddr[4], rime, CONFIG_NET_6LOWPAN_RIMEADDR_SIZE);
}

/****************************************************************************
 * Name: sixlowpan_rimefromip
 *
 * Description:
 *   Assume stateless auto-configuration to extrate the rime address from
 *   an IP address:
 *
 *    128  112  96   80    64   48   32   16
 *    ---- ---- ---- ----  ---- ---- ---- ----
 *    fe80 0000 0000 0000  xxxx xxxx 0000 0000 2-byte Rime address (VALID?)
 *    fe80 0000 0000 0000  xxxx xxxx xxxx xxxx 8-byte Rime address
 *
 ****************************************************************************/

void sixlowpan_rimefromip(const net_ipv6addr_t ipaddr,
                          FAR struct rimeaddr_s *rime)
{
  /* REVISIT: See notes about 2 byte addresses in sixlowpan_ipfromrime() */

  DEBUGASSERT(ipaddr[0] == 0xfe80);

  memcpy(rime, &ipaddr[4], CONFIG_NET_6LOWPAN_RIMEADDR_SIZE);
}

#endif /* CONFIG_NET_6LOWPAN */