icmp6.c

嵌入式TCpip协议栈 开源代码

/*
 * Copyright (c) 2001, 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. 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. 
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <[e-mail]>
 *
 * $Id: icmp6.c,v 1.1 2001/12/12 10:00:59 adam Exp $
 */

/* Some ICMP messages should be passed to the transport protocols. This
   is not implemented. */

#include "lwip/debug.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)
{
  unsigned char type;
  struct icmp_echo_hdr *iecho;
  struct ip_hdr *iphdr;
  struct ip_addr tmpaddr;
  
 
#ifdef ICMP_STATS
  ++stats.icmp.recv;
#endif /* ICMP_STATS */

  type = ((char *)p->payload)[0];

  switch(type) {
  case ICMP6_ECHO:
    DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));

    if(p->tot_len < sizeof(struct icmp_echo_hdr)) {
      DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));

      pbuf_free(p);
#ifdef ICMP_STATS
      ++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) {
      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
      ++stats.icmp.chkerr;
#endif /* ICMP_STATS */
    /*      return;*/
    }
    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);
    }
    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
    ++stats.icmp.xmit;
#endif /* ICMP_STATS */

    /*    DEBUGF("icmp: p->len %d p->tot_len %d\n", p->len, p->tot_len);*/
    ip_output_if(p, &(iphdr->src), IP_HDRINCL,
		 iphdr->hoplim, IP_PROTO_ICMP, inp);
    break; 
  default:
    DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type not supported.\n"));

#ifdef ICMP_STATS
    ++stats.icmp.proterr;
    ++stats.icmp.drop;
#endif /* ICMP_STATS */
  }

  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_TRANSPORT, 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;

  bcopy(p->payload, (char *)q->payload + 8, IP_HLEN + 8);
  
  /* calculate checksum */
  idur->chksum = 0;
  idur->chksum = inet_chksum(idur, q->len);
#ifdef ICMP_STATS
  ++stats.icmp.xmit;
#endif /* ICMP_STATS */

  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;

  DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded\n"));
  
  q = pbuf_alloc(PBUF_TRANSPORT, 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 */
  bcopy((char *)p->payload, (char *)q->payload + 8, IP_HLEN + 8);
  
  /* calculate checksum */
  tehdr->chksum = 0;
  tehdr->chksum = inet_chksum(tehdr, q->len);
#ifdef ICMP_STATS
  ++stats.icmp.xmit;
#endif /* ICMP_STATS */
  ip_output(q, NULL, 
	    (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
  pbuf_free(q);
}