www.pudn.com > lwip-1.3.0.rar > icmp6.c

/* 
 * 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  
 * 
 */ 
 
/* Some ICMP messages should be passed to the transport protocols. This 
   is not implemented. */ 
 
#include "lwip/opt.h" 
 
#if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */ 
 
#include "lwip/icmp.h" 
#include "lwip/inet.h" 
#include "lwip/ip.h" 
#include "lwip/def.h" 
#include "lwip/stats.h" 
 
void 
icmp_input(struct pbuf *p, struct netif *inp) 
{ 
  u8_t type; 
  struct icmp_echo_hdr *iecho; 
  struct ip_hdr *iphdr; 
  struct ip_addr tmpaddr; 
 
  ICMP_STATS_INC(icmp.recv); 
 
  /* TODO: check length before accessing payload! */ 
 
  type = ((u8_t *)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); 
      ICMP_STATS_INC(icmp.lenerr); 
      return; 
    } 
    iecho = p->payload; 
    iphdr = (struct ip_hdr *)((u8_t *)p->payload - IP_HLEN); 
    if (inet_chksum_pbuf(p) != 0) { 
      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo (%"X16_F")\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len))); 
      ICMP_STATS_INC(icmp.chkerr); 
    /*      return;*/ 
    } 
    LWIP_DEBUGF(ICMP_DEBUG, ("icmp: p->len %"S16_F" p->tot_len %"S16_F"\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 (%"X16_F")\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len))); 
    ICMP_STATS_INC(icmp.xmit); 
 
    /*    LWIP_DEBUGF("icmp: p->len %"U16_F" p->tot_len %"U16_F"\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 %"S16_F" not supported.\n", (s16_t)type)); 
    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; 
 
  /* @todo: can this be PBUF_LINK instead of PBUF_IP? */ 
  q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM); 
  /* ICMP header + IP header + 8 bytes of data */ 
  if (q == NULL) { 
    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n")); 
    pbuf_free(p); 
    return; 
  } 
  LWIP_ASSERT("check that first pbuf can hold icmp message", 
             (q->len >= (8 + IP_HLEN + 8))); 
 
  iphdr = p->payload; 
 
  idur = q->payload; 
  idur->type = (u8_t)ICMP6_DUR; 
  idur->icode = (u8_t)t; 
 
  SMEMCPY((u8_t *)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); 
 
  ip_output(q, NULL, 
      (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP); 
  pbuf_free(q); 
} 
 
void 
icmp_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")); 
 
  /* @todo: can this be PBUF_LINK instead of PBUF_IP? */ 
  q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM); 
  /* ICMP header + IP header + 8 bytes of data */ 
  if (q == NULL) { 
    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n")); 
    pbuf_free(p); 
    return; 
  } 
  LWIP_ASSERT("check that first pbuf can hold icmp message", 
             (q->len >= (8 + IP_HLEN + 8))); 
 
  iphdr = p->payload; 
 
  tehdr = q->payload; 
  tehdr->type = (u8_t)ICMP6_TE; 
  tehdr->icode = (u8_t)t; 
 
  /* copy fields from original packet */ 
  SMEMCPY((u8_t *)q->payload + 8, (u8_t *)p->payload, IP_HLEN + 8); 
 
  /* calculate checksum */ 
  tehdr->chksum = 0; 
  tehdr->chksum = inet_chksum(tehdr, q->len); 
  ICMP_STATS_INC(icmp.xmit); 
  ip_output(q, NULL, 
      (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP); 
  pbuf_free(q); 
} 
 
#endif /* LWIP_ICMP */