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/* icmp.c - ICMP support for sendip
* Author: Mike Ricketts <mike@earth.li>
* ChangeLog since 2.0 release:
* 02/12/2001: Moved ipv6_csum into here as this is where it is used.
* 02/12/2001: Merged icmp6csum with ipv6_csum
* 02/12/2001: Only check one layer of headers for enclosing ipv[46] header
* 22/01/2002: Include string.h
* 22/02/2002: Fix alignment problem in icmp*csum
* ChangeLog since 2.1 release:
* 16/04/2002: Move ipv6_pseudo_header into ipv6.h so tcp.c and udp.c can get it
* ChangeLog since 2.4 release:
* 21/04/2003: Fix errors detected by valgrind
*/
#include <sys/types.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <string.h>
#include "sendip_module.h"
#include "icmp.h"
#include "ipv4.h"
#include "ipv6.h"
/* Character that identifies our options
*/
const char opt_char='c';
static void icmpcsum(sendip_data *icmp_hdr, sendip_data *data) {
icmp_header *icp = (icmp_header *)icmp_hdr->data;
u_int16_t *buf = malloc(icmp_hdr->alloc_len+data->alloc_len);
u_int8_t *tempbuf = (u_int8_t *)buf;
icp->check = 0;
if(tempbuf == NULL) {
fprintf(stderr,"Out of memory: ICMP checksum not computed\n");
return;
}
memcpy(tempbuf,icmp_hdr->data,icmp_hdr->alloc_len);
memcpy(tempbuf+icmp_hdr->alloc_len,data->data,data->alloc_len);
icp->check = csum(buf,icmp_hdr->alloc_len+data->alloc_len);
free(buf);
}
static void icmp6csum(struct in6_addr *src, struct in6_addr *dst,
sendip_data *hdr, sendip_data *data) {
icmp_header *icp = (icmp_header *)hdr->data;
struct ipv6_pseudo_hdr phdr;
/* Make sure tempbuf is word aligned */
u_int16_t *buf = malloc(sizeof(phdr)+hdr->alloc_len+data->alloc_len);
u_int8_t *tempbuf = (u_int8_t *)buf;
icp->check = 0;
if(tempbuf == NULL) {
fprintf(stderr,"Out of memory: ICMP checksum not computed\n");
return;
}
memcpy(tempbuf+sizeof(phdr), hdr->data, hdr->alloc_len);
memcpy(tempbuf+sizeof(phdr)+hdr->alloc_len, data->data, data->alloc_len);
/* do an ipv6 checksum */
memset(&phdr, 0, sizeof(phdr));
memcpy(&phdr.source, src, sizeof(struct in6_addr));
memcpy(&phdr.destination, dst, sizeof(struct in6_addr));
phdr.ulp_length = htonl(hdr->alloc_len+data->alloc_len);
phdr.nexthdr = IPPROTO_ICMPV6;
memcpy(tempbuf, &phdr, sizeof(phdr));
icp->check = csum(buf,sizeof(phdr)+hdr->alloc_len+data->alloc_len);
free(buf);
}
sendip_data *initialize(void) {
sendip_data *ret = malloc(sizeof(sendip_data));
icmp_header *icmp = malloc(sizeof(icmp_header));
memset(icmp,0,sizeof(icmp_header));
ret->alloc_len = sizeof(icmp_header);
ret->data = (void *)icmp;
ret->modified=0;
return ret;
}
bool do_opt(char *opt, char *arg, sendip_data *pack) {
icmp_header *icp = (icmp_header *)pack->data;
switch(opt[1]) {
case 't':
icp->type = (u_int8_t)strtoul(arg, (char **)NULL, 0);
pack->modified |= ICMP_MOD_TYPE;
break;
case 'd':
icp->code = (u_int8_t)strtoul(arg, (char **)NULL, 0);
pack->modified |= ICMP_MOD_CODE;
break;
case 'c':
icp->check = htons((u_int16_t)strtoul(arg, (char **)NULL, 0));
pack->modified |= ICMP_MOD_CHECK;
break;
}
return TRUE;
}
bool finalize(char *hdrs, sendip_data *headers[], sendip_data *data,
sendip_data *pack) {
icmp_header *icp = (icmp_header *)pack->data;
int i=strlen(hdrs)-1;
/* Find enclosing IP header and do the checksum */
if(hdrs[i]=='i') {
// ipv4
if(!(headers[i]->modified&IP_MOD_PROTOCOL)) {
((ip_header *)(headers[i]->data))->protocol=IPPROTO_ICMP;
headers[i]->modified |= IP_MOD_PROTOCOL;
}
} else if(hdrs[i]=='6') {
// ipv6
if(!(headers[i]->modified&IPV6_MOD_NXT)) {
((ipv6_header *)(headers[i]->data))->ip6_nxt=IPPROTO_ICMPV6;
headers[i]->modified |= IPV6_MOD_NXT;
}
}
if(!(pack->modified&ICMP_MOD_TYPE)) {
if(hdrs[i]=='6') {
icp->type=ICMP6_ECHO_REQUEST;
} else {
icp->type=ICMP_ECHO;
}
}
if(!(pack->modified&ICMP_MOD_CHECK)) {
if (hdrs[i] == '6') {
// ipv6
struct in6_addr *src, *dst;
src = (struct in6_addr *)&(((ipv6_header *)(headers[i]->data))->ip6_src);
dst = (struct in6_addr *)&(((ipv6_header *)(headers[i]->data))->ip6_dst);
icmp6csum(src, dst, pack, data);
} else {
// ipv4 or anything else
icmpcsum(pack,data);
}
}
return TRUE;
}
int num_opts() {
return sizeof(icmp_opts)/sizeof(sendip_option);
}
sendip_option *get_opts() {
return icmp_opts;
}
char get_optchar() {
return opt_char;
}
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