www.pudn.com > TCPmodbushy.rar > icmp.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
#include "o:/lwip/opt.h"
#include "o:/IPV4/lwip/icmp.h"
#include "o:/IPV4/lwip/inet.h"
#include "o:/IPV4/lwip/ip.h"
#include "o:/lwip/def.h"
#include "o:/lwip/stats.h"
#include "o:/lwip/snmp.h"
void
icmp_input(struct pbuf xdata *p)
{
u8_t type;
u8_t Re_code;
struct icmp_echo_hdr xdata *iecho;
struct ip_hdr xdata *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 (%"U16_F" bytes) received\n", p->tot_len));
pbuf_free(p);
ICMP_STATS_INC(icmp.lenerr);
snmp_inc_icmpinerrors();
return;
}
type = *((u8_t xdata *)p->payload);
Re_code = *(((u8_t xdata *)p->payload)+1);
switch (type) {
case ICMP_ECHO:
/* broadcast or multicast destination address? */
if (ip_addr_isbroadcast(&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), IP_PROTO_ICMP);
break;
default:
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" Re_code %"S16_F" not supported.\n", (s16_t)type, (s16_t)Re_code));
ICMP_STATS_INC(icmp.proterr);
ICMP_STATS_INC(icmp.drop);
}
pbuf_free(p);
}
void
icmp_dest_unreach(struct pbuf xdata *p, enum icmp_dur_type t)
{
struct pbuf xdata *q;
struct ip_hdr xdata *iphdr;
struct icmp_dur_hdr xdata *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((u8_t xdata *)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_if(q, NULL, &(iphdr->src),
ICMP_TTL, IP_PROTO_ICMP);
pbuf_free(q);
}
#if IP_FORWARD
void
icmp_time_exceeded(struct pbuf xdata *p, enum icmp_te_type t)
{
struct pbuf xdata *q;
struct ip_hdr xdata *iphdr;
struct icmp_te_hdr xdata *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((u8_t xdata *)q->payload + 8, (u8_t xdata *)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_if(q, NULL, &(iphdr->src),
ICMP_TTL, IP_PROTO_ICMP);
pbuf_free(q);
}
#endif /* IP_FORWARD */