/*
 * Copyright (c) 2001-2003, Adam Dunkels.
 * All rights reserved.
 *
 * 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. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * This file is part of the uIP TCP/IP stack.
 *
 */

/**
 * \addtogroup uip6
 * @{
 */

/**
 * \file
 *    ICMPv6 (RFC 4443) implementation, with message and error handling
 * \author Julien Abeille <jabeille@cisco.com> 
 * \author Mathilde Durvy <mdurvy@cisco.com>
 */

#include <net/ip_buf.h>

#include <string.h>
#include "contiki/ipv6/uip-ds6.h"
#include "contiki/ipv6/uip-icmp6.h"
#include "contiki-default-conf.h"

#ifdef CONFIG_NETWORK_IP_STACK_DEBUG_IPV6_ICMPV6
#define DEBUG 1
#endif
#include "contiki/ip/uip-debug.h"

#define UIP_IP_BUF(buf)                ((struct uip_ip_hdr *)&uip_buf(buf)[UIP_LLH_LEN])
#define UIP_ICMP_BUF(buf)            ((struct uip_icmp_hdr *)&uip_buf(buf)[uip_l2_l3_hdr_len(buf)])
#define UIP_ICMP6_ERROR_BUF(buf)  ((struct uip_icmp6_error *)&uip_buf(buf)[uip_l2_l3_icmp_hdr_len(buf)])
#define UIP_EXT_BUF(buf)              ((struct uip_ext_hdr *)&uip_buf(buf)[uip_l2_l3_hdr_len(buf)])
#define UIP_FIRST_EXT_BUF(buf)        ((struct uip_ext_hdr *)&uip_buf(buf)[UIP_LLIPH_LEN])

#if UIP_CONF_IPV6_RPL
#include "rpl/rpl.h"
#endif /* UIP_CONF_IPV6_RPL */

#if 0
/* Moved this to individual functions to make the API re-entrant */
/** \brief temporary IP address */
static uip_ipaddr_t tmp_ipaddr;
#endif

LIST(echo_reply_callback_list);
/*---------------------------------------------------------------------------*/
/* List of input handlers */
LIST(input_handler_list);
/*---------------------------------------------------------------------------*/
static uip_icmp6_input_handler_t *
input_handler_lookup(uint8_t type, uint8_t icode)
{
  uip_icmp6_input_handler_t *handler = NULL;

  for(handler = list_head(input_handler_list);
      handler != NULL;
      handler = list_item_next(handler)) {
    if(handler->type == type &&
       (handler->icode == icode ||
        handler->icode == UIP_ICMP6_HANDLER_CODE_ANY)) {
      return handler;
    }
  }

  return NULL;
}
/*---------------------------------------------------------------------------*/
uint8_t
uip_icmp6_input(struct net_buf *buf, uint8_t type, uint8_t icode)
{
  uip_icmp6_input_handler_t *handler = input_handler_lookup(type, icode);

  if(handler == NULL) {
    return UIP_ICMP6_INPUT_ERROR;
  }

  if(handler->handler == NULL) {
    return UIP_ICMP6_INPUT_ERROR;
  }

  handler->handler(buf);
  return UIP_ICMP6_INPUT_SUCCESS;
}
/*---------------------------------------------------------------------------*/
void
uip_icmp6_register_input_handler(uip_icmp6_input_handler_t *handler)
{
  list_add(input_handler_list, handler);
}
/*---------------------------------------------------------------------------*/
static void
echo_request_input(struct net_buf *buf)
{
#if UIP_CONF_IPV6_RPL
  uint8_t temp_ext_len;
#endif /* UIP_CONF_IPV6_RPL */
  /*
   * we send an echo reply. It is trivial if there was no extension
   * headers in the request otherwise we need to remove the extension
   * headers and change a few fields
   */
  PRINTF("Received Echo Request from ");
  PRINT6ADDR(&UIP_IP_BUF(buf)->srcipaddr);
  PRINTF(" to ");
  PRINT6ADDR(&UIP_IP_BUF(buf)->destipaddr);
  PRINTF("\n");

  /* IP header */
  UIP_IP_BUF(buf)->ttl = uip_ds6_if.cur_hop_limit;

  if(uip_is_addr_mcast(&UIP_IP_BUF(buf)->destipaddr)){
    uip_ipaddr_copy(&UIP_IP_BUF(buf)->destipaddr, &UIP_IP_BUF(buf)->srcipaddr);
    uip_ds6_select_src(&UIP_IP_BUF(buf)->srcipaddr, &UIP_IP_BUF(buf)->destipaddr);
  } else {
    uip_ipaddr_t tmp_ipaddr;

    uip_ipaddr_copy(&tmp_ipaddr, &UIP_IP_BUF(buf)->srcipaddr);
    uip_ipaddr_copy(&UIP_IP_BUF(buf)->srcipaddr, &UIP_IP_BUF(buf)->destipaddr);
    uip_ipaddr_copy(&UIP_IP_BUF(buf)->destipaddr, &tmp_ipaddr);
  }

  if(uip_ext_len(buf) > 0) {
#if UIP_CONF_IPV6_RPL
    if((temp_ext_len = rpl_invert_header(buf))) {
      /* If there were other extension headers*/
      UIP_FIRST_EXT_BUF(buf)->next = UIP_PROTO_ICMP6;
      if (uip_ext_len(buf) != temp_ext_len) {
        uip_len(buf) -= (uip_ext_len(buf) - temp_ext_len);
        UIP_IP_BUF(buf)->len[0] = ((uip_len(buf) - UIP_IPH_LEN) >> 8);
        UIP_IP_BUF(buf)->len[1] = ((uip_len(buf) - UIP_IPH_LEN) & 0xff);
        /* move the echo request payload (starting after the icmp header)
         * to the new location in the reply.
         * The shift is equal to the length of the remaining extension headers present
         * Note: UIP_ICMP_BUF still points to the echo request at this stage
         */
        memmove((uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN - (uip_ext_len(buf) - temp_ext_len),
              (uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN,
              (uip_len(buf) - UIP_IPH_LEN - temp_ext_len - UIP_ICMPH_LEN));
      }
      uip_ext_len(buf) = temp_ext_len;
    } else {
#endif /* UIP_CONF_IPV6_RPL */
      /* If there were extension headers*/
      UIP_IP_BUF(buf)->proto = UIP_PROTO_ICMP6;
      uip_len(buf) -= uip_ext_len(buf);
      UIP_IP_BUF(buf)->len[0] = ((uip_len(buf) - UIP_IPH_LEN) >> 8);
      UIP_IP_BUF(buf)->len[1] = ((uip_len(buf) - UIP_IPH_LEN) & 0xff);
      /* move the echo request payload (starting after the icmp header)
       * to the new location in the reply.
       * The shift is equal to the length of the extension headers present
       * Note: UIP_ICMP_BUF still points to the echo request at this stage
       */
      memmove((uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN - uip_ext_len(buf),
              (uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN,
              (uip_len(buf) - UIP_IPH_LEN - UIP_ICMPH_LEN));
      uip_ext_len(buf) = 0;
#if UIP_CONF_IPV6_RPL
    }
#endif /* UIP_CONF_IPV6_RPL */
  }
  /* Below is important for the correctness of UIP_ICMP_BUF and the
   * checksum
   */

  /* Note: now UIP_ICMP_BUF points to the beginning of the echo reply */
  UIP_ICMP_BUF(buf)->type = ICMP6_ECHO_REPLY;
  UIP_ICMP_BUF(buf)->icode = 0;
  UIP_ICMP_BUF(buf)->icmpchksum = 0;
  UIP_ICMP_BUF(buf)->icmpchksum = ~uip_icmp6chksum(buf);

  PRINTF("Sending Echo Reply to ");
  PRINT6ADDR(&UIP_IP_BUF(buf)->destipaddr);
  PRINTF(" from ");
  PRINT6ADDR(&UIP_IP_BUF(buf)->srcipaddr);
  PRINTF("\n");
  UIP_STAT(++uip_stat.icmp.sent);
  return;
}
/*---------------------------------------------------------------------------*/
void
uip_icmp6_error_output(struct net_buf *buf, uint8_t type, uint8_t code, uint32_t param) {

 uip_ipaddr_t tmp_ipaddr;

 /* check if originating packet is not an ICMP error*/
  if (uip_ext_len(buf)) {
    if(UIP_EXT_BUF(buf)->next == UIP_PROTO_ICMP6 && UIP_ICMP_BUF(buf)->type < 128){
      uip_len(buf) = 0;
      return;
    }
  } else {
    if(UIP_IP_BUF(buf)->proto == UIP_PROTO_ICMP6 && UIP_ICMP_BUF(buf)->type < 128){
      uip_len(buf) = 0;
      return;
    }
  }

#if UIP_CONF_IPV6_RPL
  uip_ext_len(buf) = rpl_invert_header(buf);
#else /* UIP_CONF_IPV6_RPL */
  uip_ext_len(buf) = 0;
#endif /* UIP_CONF_IPV6_RPL */

  /* remember data of original packet before shifting */
  uip_ipaddr_copy(&tmp_ipaddr, &UIP_IP_BUF(buf)->destipaddr);

  uip_len(buf) += UIP_IPICMPH_LEN + UIP_ICMP6_ERROR_LEN;

  if(uip_len(buf) > UIP_LINK_MTU)
    uip_len(buf) = UIP_LINK_MTU;

  memmove((uint8_t *)UIP_ICMP6_ERROR_BUF(buf) + uip_ext_len(buf) + UIP_ICMP6_ERROR_LEN,
          (void *)UIP_IP_BUF(buf), uip_len(buf) - UIP_IPICMPH_LEN - uip_ext_len(buf) - UIP_ICMP6_ERROR_LEN);

  UIP_IP_BUF(buf)->vtc = 0x60;
  UIP_IP_BUF(buf)->tcflow = 0;
  UIP_IP_BUF(buf)->flow = 0;
  if (uip_ext_len(buf)) {
    UIP_FIRST_EXT_BUF(buf)->next = UIP_PROTO_ICMP6;
  } else {
    UIP_IP_BUF(buf)->proto = UIP_PROTO_ICMP6;
  }
  UIP_IP_BUF(buf)->ttl = uip_ds6_if.cur_hop_limit;

  /* the source should not be unspecified nor multicast, the check for
     multicast is done in uip_process */
  if(uip_is_addr_unspecified(&UIP_IP_BUF(buf)->srcipaddr)){
    uip_len(buf) = 0;
    return;
  }

  uip_ipaddr_copy(&UIP_IP_BUF(buf)->destipaddr, &UIP_IP_BUF(buf)->srcipaddr);

  if(uip_is_addr_mcast(&tmp_ipaddr)){
    if(type == ICMP6_PARAM_PROB && code == ICMP6_PARAMPROB_OPTION){
      uip_ds6_select_src(&UIP_IP_BUF(buf)->srcipaddr, &tmp_ipaddr);
    } else {
      uip_len(buf) = 0;
      return;
    }
  } else {
#if UIP_CONF_ROUTER
    /* need to pick a source that corresponds to this node */
    uip_ds6_select_src(&UIP_IP_BUF(buf)->srcipaddr, &tmp_ipaddr);
#else
    uip_ipaddr_copy(&UIP_IP_BUF(buf)->srcipaddr, &tmp_ipaddr);
#endif
  }

  UIP_ICMP_BUF(buf)->type = type;
  UIP_ICMP_BUF(buf)->icode = code;
  UIP_ICMP6_ERROR_BUF(buf)->param = uip_htonl(param);
  UIP_IP_BUF(buf)->len[0] = ((uip_len(buf) - UIP_IPH_LEN) >> 8);
  UIP_IP_BUF(buf)->len[1] = ((uip_len(buf) - UIP_IPH_LEN) & 0xff);
  UIP_ICMP_BUF(buf)->icmpchksum = 0;
  UIP_ICMP_BUF(buf)->icmpchksum = ~uip_icmp6chksum(buf);

  UIP_STAT(++uip_stat.icmp.sent);

  PRINTF("Sending ICMPv6 ERROR message type %d code %d to ", type, code);
  PRINT6ADDR(&UIP_IP_BUF(buf)->destipaddr);
  PRINTF(" from ");
  PRINT6ADDR(&UIP_IP_BUF(buf)->srcipaddr);
  PRINTF("\n");
  return;
}

/*---------------------------------------------------------------------------*/
void
uip_icmp6_send(struct net_buf *buf, const uip_ipaddr_t *dest, int type, int code, int payload_len)
{

  UIP_IP_BUF(buf)->vtc = 0x60;
  UIP_IP_BUF(buf)->tcflow = 0;
  UIP_IP_BUF(buf)->flow = 0;
  UIP_IP_BUF(buf)->proto = UIP_PROTO_ICMP6;
  UIP_IP_BUF(buf)->ttl = uip_ds6_if.cur_hop_limit;
  UIP_IP_BUF(buf)->len[0] = (UIP_ICMPH_LEN + payload_len) >> 8;
  UIP_IP_BUF(buf)->len[1] = (UIP_ICMPH_LEN + payload_len) & 0xff;

  memcpy(&UIP_IP_BUF(buf)->destipaddr, dest, sizeof(*dest));
  uip_ds6_select_src(&UIP_IP_BUF(buf)->srcipaddr, &UIP_IP_BUF(buf)->destipaddr);

  UIP_ICMP_BUF(buf)->type = type;
  UIP_ICMP_BUF(buf)->icode = code;

  UIP_ICMP_BUF(buf)->icmpchksum = 0;
  UIP_ICMP_BUF(buf)->icmpchksum = ~uip_icmp6chksum(buf);

  uip_len(buf) = UIP_IPH_LEN + UIP_ICMPH_LEN + payload_len;
  net_buf_add(buf, uip_len(buf));

  tcpip_ipv6_output(buf);
}
/*---------------------------------------------------------------------------*/
static void
echo_reply_input(struct net_buf *buf)
{
  int ttl;
  uip_ipaddr_t sender;
#if UIP_CONF_IPV6_RPL
  uint8_t temp_ext_len;
#endif /* UIP_CONF_IPV6_RPL */

  uip_ipaddr_copy(&sender, &UIP_IP_BUF(buf)->srcipaddr);
  ttl = UIP_IP_BUF(buf)->ttl;

  if(uip_ext_len(buf) > 0) {
#if UIP_CONF_IPV6_RPL
    if((temp_ext_len = rpl_invert_header(buf))) {
      /* If there were other extension headers*/
      UIP_FIRST_EXT_BUF(buf)->next = UIP_PROTO_ICMP6;
      if (uip_ext_len(buf) != temp_ext_len) {
        uip_len(buf) -= (uip_ext_len(buf) - temp_ext_len);
        UIP_IP_BUF(buf)->len[0] = ((uip_len(buf) - UIP_IPH_LEN) >> 8);
        UIP_IP_BUF(buf)->len[1] = ((uip_len(buf) - UIP_IPH_LEN) & 0xff);
        /* move the echo reply payload (starting after the icmp
         * header) to the new location in the reply.  The shift is
         * equal to the length of the remaining extension headers
         * present Note: UIP_ICMP_BUF still points to the echo reply
         * at this stage
         */
        memmove((uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN - (uip_ext_len(buf) - temp_ext_len),
                (uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN,
                (uip_len(buf) - UIP_IPH_LEN - temp_ext_len - UIP_ICMPH_LEN));
      }
      uip_ext_len(buf) = temp_ext_len;
      uip_len(buf) -= uip_ext_len(buf);
    } else {
#endif /* UIP_CONF_IPV6_RPL */
      /* If there were extension headers*/
      UIP_IP_BUF(buf)->proto = UIP_PROTO_ICMP6;
      uip_len(buf) -= uip_ext_len(buf);
      UIP_IP_BUF(buf)->len[0] = ((uip_len(buf) - UIP_IPH_LEN) >> 8);
      UIP_IP_BUF(buf)->len[1] = ((uip_len(buf) - UIP_IPH_LEN) & 0xff);
      /* move the echo reply payload (starting after the icmp header)
       * to the new location in the reply.  The shift is equal to the
       * length of the extension headers present Note: UIP_ICMP_BUF
       * still points to the echo request at this stage
       */
      memmove((uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN - uip_ext_len(buf),
              (uint8_t *)UIP_ICMP_BUF(buf) + UIP_ICMPH_LEN,
              (uip_len(buf) - UIP_IPH_LEN - UIP_ICMPH_LEN));
      uip_ext_len(buf) = 0;
#if UIP_CONF_IPV6_RPL
    }
#endif /* UIP_CONF_IPV6_RPL */
  }

  /* Call all registered applications to let them know an echo reply
     has been received. */
  {
    struct uip_icmp6_echo_reply_notification *n;
    for(n = list_head(echo_reply_callback_list);
        n != NULL;
        n = list_item_next(n)) {
      if(n->callback != NULL) {
        n->callback(&sender, ttl,
                    (uint8_t *)&UIP_ICMP_BUF(buf)[sizeof(struct uip_icmp_hdr)],
                    uip_len(buf) - sizeof(struct uip_icmp_hdr) - UIP_IPH_LEN);
      }
    }
  }

  uip_len(buf) = 0;
  return;
}
/*---------------------------------------------------------------------------*/
void
uip_icmp6_echo_reply_callback_add(struct uip_icmp6_echo_reply_notification *n,
                                  uip_icmp6_echo_reply_callback_t c)
{
  if(n != NULL && c != NULL) {
    n->callback = c;
    list_add(echo_reply_callback_list, n);
  }
}
/*---------------------------------------------------------------------------*/
void
uip_icmp6_echo_reply_callback_rm(struct uip_icmp6_echo_reply_notification *n)
{
  list_remove(echo_reply_callback_list, n);
}
/*---------------------------------------------------------------------------*/
UIP_ICMP6_HANDLER(echo_request_handler, ICMP6_ECHO_REQUEST,
                  UIP_ICMP6_HANDLER_CODE_ANY, echo_request_input);
UIP_ICMP6_HANDLER(echo_reply_handler, ICMP6_ECHO_REPLY,
                  UIP_ICMP6_HANDLER_CODE_ANY, echo_reply_input);
/*---------------------------------------------------------------------------*/
void
uip_icmp6_init()
{
  /* Register Echo Request and Reply handlers */
  uip_icmp6_register_input_handler(&echo_request_handler);
  uip_icmp6_register_input_handler(&echo_reply_handler);
}
/*---------------------------------------------------------------------------*/
/** @} */