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/* udp.c - UDP code for sendip
* Author: Mike Ricketts <mike@earth.li>
* ChangeLog since 2.0 release:
* ChangeLog since 2.1 release:
* 16/04/2002: Only check one layer of enclosing headers for ip
* 16/04/2002: Add support for UDP over IPV6
* ChangeLog since 2.4 release:
* 21/04/2003: Fix errors found by valgrind
* ChangeLog since 2.5 release:
* 03/11/2006: Fix UDPv6 checksum error found by biplab sarkar
*/
#include <sys/types.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <string.h>
#include "sendip_module.h"
#include "udp.h"
#include "ipv4.h"
#include "ipv6.h"
/* Character that identifies our options
*/
const char opt_char='u';
static void udpcsum(sendip_data *ip_hdr, sendip_data *udp_hdr,
sendip_data *data) {
udp_header *udp = (udp_header *)udp_hdr->data;
ip_header *ip = (ip_header *)ip_hdr->data;
u_int16_t *buf = malloc(12+udp_hdr->alloc_len+data->alloc_len);
u_int8_t *tempbuf = (u_int8_t *)buf;
udp->check=0;
if(tempbuf == NULL) {
fprintf(stderr,"Out of memory: UDP checksum not computed\n");
return;
}
/* Set up the pseudo header */
memcpy(tempbuf,&(ip->saddr),sizeof(u_int32_t));
memcpy(&(tempbuf[4]),&(ip->daddr),sizeof(u_int32_t));
tempbuf[8]=0;
tempbuf[9]=(u_int16_t)ip->protocol;
tempbuf[10]=(u_int16_t)((udp_hdr->alloc_len+data->alloc_len)&0xFF00)>>8;
tempbuf[11]=(u_int16_t)((udp_hdr->alloc_len+data->alloc_len)&0x00FF);
/* Copy the UDP header and data */
memcpy(tempbuf+12,udp_hdr->data,udp_hdr->alloc_len);
memcpy(tempbuf+12+udp_hdr->alloc_len,data->data,data->alloc_len);
/* CheckSum it */
udp->check = csum(buf,12+udp_hdr->alloc_len+data->alloc_len);
free(buf);
}
static void udp6csum(sendip_data *ipv6_hdr, sendip_data *udp_hdr,
sendip_data *data) {
udp_header *udp = (udp_header *)udp_hdr->data;
ipv6_header *ipv6 = (ipv6_header *)ipv6_hdr->data;
struct ipv6_pseudo_hdr phdr;
u_int16_t *buf = malloc(sizeof(phdr)+udp_hdr->alloc_len+data->alloc_len);
u_int8_t *tempbuf = (u_int8_t *)buf;
udp->check=0;
if(tempbuf == NULL) {
fprintf(stderr,"Out of memory: UDP checksum not computed\n");
return;
}
/* Set up the pseudo header */
memset(&phdr,0,sizeof(phdr));
memcpy(&phdr.source,&ipv6->ip6_src,sizeof(struct in6_addr));
memcpy(&phdr.destination,&ipv6->ip6_dst,sizeof(struct in6_addr));
phdr.nexthdr=IPPROTO_UDP;
phdr.ulp_length=udp->len;
memcpy(tempbuf,&phdr,sizeof(phdr));
/* Copy the UDP header and data */
memcpy(tempbuf+sizeof(phdr),udp_hdr->data,udp_hdr->alloc_len);
memcpy(tempbuf+sizeof(phdr)+udp_hdr->alloc_len,data->data,data->alloc_len);
/* CheckSum it */
udp->check = csum(buf,sizeof(phdr)+udp_hdr->alloc_len+data->alloc_len);
free(buf);
}
sendip_data *initialize(void) {
sendip_data *ret = malloc(sizeof(sendip_data));
udp_header *udp = malloc(sizeof(udp_header));
memset(udp,0,sizeof(udp_header));
ret->alloc_len = sizeof(udp_header);
ret->data = (void *)udp;
ret->modified=0;
return ret;
}
bool do_opt(char *opt, char *arg, sendip_data *pack) {
udp_header *udp = (udp_header *)pack->data;
switch(opt[1]) {
case 's':
udp->source = htons((u_int16_t)strtoul(arg, (char **)NULL, 0));
pack->modified |= UDP_MOD_SOURCE;
break;
case 'd':
udp->dest = htons((u_int16_t)strtoul(arg, (char **)NULL, 0));
pack->modified |= UDP_MOD_DEST;
break;
case 'l':
udp->len = htons((u_int16_t)strtoul(arg, (char **)NULL, 0));
pack->modified |= UDP_MOD_LEN;
break;
case 'c':
udp->check = htons((u_int16_t)strtoul(arg, (char **)NULL, 0));
pack->modified |= UDP_MOD_CHECK;
break;
}
return TRUE;
}
bool finalize(char *hdrs, sendip_data *headers[], sendip_data *data,
sendip_data *pack) {
udp_header *udp = (udp_header *)pack->data;
/* Set relevant fields */
if(!(pack->modified&UDP_MOD_LEN)) {
udp->len=htons(pack->alloc_len+data->alloc_len);
}
/* Find enclosing IP header and do the checksum */
if(hdrs[strlen(hdrs)-1]=='i') {
int i = strlen(hdrs)-1;
if(!(headers[i]->modified&IP_MOD_PROTOCOL)) {
((ip_header *)(headers[i]->data))->protocol=IPPROTO_UDP;
headers[i]->modified |= IP_MOD_PROTOCOL;
}
if(!(pack->modified&UDP_MOD_CHECK)) {
udpcsum(headers[i],pack,data);
}
} else if(hdrs[strlen(hdrs)-1]=='6') {
int i = strlen(hdrs)-1;
if(!(headers[i]->modified&IPV6_MOD_NXT)) {
((ipv6_header *)(headers[i]->data))->ip6_nxt=IPPROTO_UDP;
headers[i]->modified |= IPV6_MOD_NXT;
}
if(!(pack->modified&UDP_MOD_CHECK)) {
udp6csum(headers[i],pack,data);
}
} else {
if(!(pack->modified&UDP_MOD_CHECK)) {
usage_error("UDP checksum not defined when UDP is not embedded in IP\n");
return FALSE;
}
}
return TRUE;
}
int num_opts() {
return sizeof(udp_opts)/sizeof(sendip_option);
}
sendip_option *get_opts() {
return udp_opts;
}
char get_optchar() {
return opt_char;
}
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