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/*

 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.

 * 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 lwIP TCP/IP stack.

 *

 * Author: Adam Dunkels <adam@sics.se>

 *

 */

/* Some ICMP messages should be passed to the transport protocols. This

   is not implemented. */

#include "lwip/opt.h"

#include "lwip/icmp.h"

#include "lwip/inet.h"

#include "lwip/ip.h"

#include "lwip/def.h"

#include "lwip/stats.h"

#include "lwip/snmp.h"

#include <string.h>

void

icmp_input(struct pbuf *p, struct netif *inp)

{

  unsigned char type;

  unsigned char code;

  struct icmp_echo_hdr *iecho;

  struct ip_hdr *iphdr;

  struct ip_addr tmpaddr;

  u16_t hlen;

  ICMP_STATS_INC(icmp.recv);

  snmp_inc_icmpinmsgs();

  iphdr = p->payload;

  hlen = IPH_HL(iphdr) * 4;

  if (pbuf_header(p, -((s16_t)hlen)) || (p->tot_len < sizeof(u16_t)*2)) {

    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%u bytes) received\n", p->tot_len));

    pbuf_free(p);

    ICMP_STATS_INC(icmp.lenerr);

    snmp_inc_icmpinerrors();

    return;

  }

  type = *((u8_t *)p->payload);

  code = *(((u8_t *)p->payload)+1);

  switch (type) {

  case ICMP_ECHO:

    /* broadcast or multicast destination address? */

    if (ip_addr_isbroadcast(&iphdr->dest, inp) || ip_addr_ismulticast(&iphdr->dest)) {

      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));

      ICMP_STATS_INC(icmp.err);

      pbuf_free(p);

      return;

    }

    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));

    if (p->tot_len < sizeof(struct icmp_echo_hdr)) {

      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));

      pbuf_free(p);

      ICMP_STATS_INC(icmp.lenerr);

      snmp_inc_icmpinerrors();

      return;

    }

    iecho = p->payload;

    if (inet_chksum_pbuf(p) != 0) {

      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));

      pbuf_free(p);

      ICMP_STATS_INC(icmp.chkerr);

      snmp_inc_icmpinerrors();

      return;

    }

    tmpaddr.addr = iphdr->src.addr;

    iphdr->src.addr = iphdr->dest.addr;

    iphdr->dest.addr = tmpaddr.addr;

    ICMPH_TYPE_SET(iecho, ICMP_ER);

    /* adjust the checksum */

    if (iecho->chksum >= htons(0xffff - (ICMP_ECHO << 8))) {

      iecho->chksum += htons(ICMP_ECHO << 8) + 1;

    } else {

      iecho->chksum += htons(ICMP_ECHO << 8);

    }

    ICMP_STATS_INC(icmp.xmit);

    /* increase number of messages attempted to send */

    snmp_inc_icmpoutmsgs();

    /* increase number of echo replies attempted to send */

    snmp_inc_icmpoutechoreps();

    pbuf_header(p, hlen);

    ip_output_if(p, &(iphdr->src), IP_HDRINCL,

                 IPH_TTL(iphdr), 0, IP_PROTO_ICMP, inp);

    break;

  default:

  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %d code %d not supported.\n", (int)type, (int)code));

    ICMP_STATS_INC(icmp.proterr);

    ICMP_STATS_INC(icmp.drop);

  }

  pbuf_free(p);

}

void

icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)

{

  struct pbuf *q;

  struct ip_hdr *iphdr;

  struct icmp_dur_hdr *idur;

  q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);

  /* ICMP header + IP header + 8 bytes of data */

  iphdr = p->payload;

  idur = q->payload;

  ICMPH_TYPE_SET(idur, ICMP_DUR);

  ICMPH_CODE_SET(idur, t);

  memcpy((char *)q->payload + 8, p->payload, IP_HLEN + 8);

  /* calculate checksum */

  idur->chksum = 0;

  idur->chksum = inet_chksum(idur, q->len);

  ICMP_STATS_INC(icmp.xmit);

  /* increase number of messages attempted to send */

  snmp_inc_icmpoutmsgs();

  /* increase number of destination unreachable messages attempted to send */

  snmp_inc_icmpoutdestunreachs();

  ip_output(q, NULL, &(iphdr->src),

            ICMP_TTL, 0, IP_PROTO_ICMP);

  pbuf_free(q);

}

#if IP_FORWARD

void

icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)

{

  struct pbuf *q;

  struct ip_hdr *iphdr;

  struct icmp_te_hdr *tehdr;

  q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);

  iphdr = p->payload;

  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));

  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));

  LWIP_DEBUGF(ICMP_DEBUG, (" to "));

  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));

  LWIP_DEBUGF(ICMP_DEBUG, ("\n"));

  tehdr = q->payload;

  ICMPH_TYPE_SET(tehdr, ICMP_TE);

  ICMPH_CODE_SET(tehdr, t);

  /* copy fields from original packet */

  memcpy((char *)q->payload + 8, (char *)p->payload, IP_HLEN + 8);

  /* calculate checksum */

  tehdr->chksum = 0;

  tehdr->chksum = inet_chksum(tehdr, q->len);

  ICMP_STATS_INC(icmp.xmit);

  /* increase number of messages attempted to send */

  snmp_inc_icmpoutmsgs();

  /* increase number of destination unreachable messages attempted to send */

  snmp_inc_icmpouttimeexcds();

  ip_output(q, NULL, &(iphdr->src),

            ICMP_TTL, 0, IP_PROTO_ICMP);

  pbuf_free(q);

}

#endif /* IP_FORWARD */