/* * 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"voidicmp_input(struct pbuf *p, struct netif *inp){  unsigned char type;  struct icmp_echo_hdr *iecho;  struct ip_hdr *iphdr;  struct ip_addr tmpaddr;#ifdef ICMP_STATS  ++lwip_stats.icmp.recv;#endif /* ICMP_STATS */  /* TODO: check length before accessing payload! */  type = ((char *)p->payload)[0];  switch (type) {  case ICMP6_ECHO:    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);#ifdef ICMP_STATS      ++lwip_stats.icmp.lenerr;#endif /* ICMP_STATS */      return;    }    iecho = p->payload;    iphdr = (struct ip_hdr *)((char *)p->payload - IP_HLEN);    if (inet_chksum_pbuf(p) != 0) {      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo (%x)\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len)));#ifdef ICMP_STATS      ++lwip_stats.icmp.chkerr;#endif /* ICMP_STATS */    /*      return;*/    }    LWIP_DEBUGF(ICMP_DEBUG, ("icmp: p->len %d p->tot_len %d\n", p->len, p->tot_len));    ip_addr_set(&tmpaddr, &(iphdr->src));    ip_addr_set(&(iphdr->src), &(iphdr->dest));    ip_addr_set(&(iphdr->dest), &tmpaddr);    iecho->type = ICMP6_ER;    /* adjust the checksum */    if (iecho->chksum >= htons(0xffff - (ICMP6_ECHO << 8))) {      iecho->chksum += htons(ICMP6_ECHO << 8) + 1;    } else {      iecho->chksum += htons(ICMP6_ECHO << 8);    }    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo (%x)\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len)));#ifdef ICMP_STATS    ++lwip_stats.icmp.xmit;#endif /* ICMP_STATS */    /*    LWIP_DEBUGF("icmp: p->len %u p->tot_len %u\n", p->len, p->tot_len);*/    ip_output_if (p, &(iphdr->src), IP_HDRINCL,     iphdr->hoplim, IP_PROTO_ICMP, inp);    break;  default:    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %d not supported.\n", (int)type));#ifdef ICMP_STATS    ++lwip_stats.icmp.proterr;    ++lwip_stats.icmp.drop;#endif /* ICMP_STATS */  }  pbuf_free(p);}voidicmp_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;  idur->type = (char)ICMP6_DUR;  idur->icode = (char)t;  memcpy((char *)q->payload + 8, p->payload, IP_HLEN + 8);  /* calculate checksum */  idur->chksum = 0;  idur->chksum = inet_chksum(idur, q->len);#ifdef ICMP_STATS  ++lwip_stats.icmp.xmit;#endif /* ICMP_STATS */  ip_output(q, NULL,      (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);  pbuf_free(q);}voidicmp_time_exceeded(struct pbuf *p, enum icmp_te_type t){  struct pbuf *q;  struct ip_hdr *iphdr;  struct icmp_te_hdr *tehdr;  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded\n"));  q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);  iphdr = p->payload;  tehdr = q->payload;  tehdr->type = (char)ICMP6_TE;  tehdr->icode = (char)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);#ifdef ICMP_STATS  ++lwip_stats.icmp.xmit;#endif /* ICMP_STATS */  ip_output(q, NULL,      (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);  pbuf_free(q);}