131 lines
3.0 KiB
C
131 lines
3.0 KiB
C
/*
|
|
* resend.c (C) 1995 Darren Reed
|
|
*
|
|
* This was written to test what size TCP fragments would get through
|
|
* various TCP/IP packet filters, as used in IP firewalls. In certain
|
|
* conditions, enough of the TCP header is missing for unpredictable
|
|
* results unless the filter is aware that this can happen.
|
|
*
|
|
*/
|
|
#if !defined(lint) && defined(LIBC_SCCS)
|
|
static char sccsid[] = "@(#)resend.c 1.3 1/11/96 (C)1995 Darren Reed";
|
|
#endif
|
|
#include <stdio.h>
|
|
#include <netdb.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <sys/types.h>
|
|
#include <sys/time.h>
|
|
#include <sys/socket.h>
|
|
#include <net/if.h>
|
|
#include <netinet/in.h>
|
|
#include <arpa/inet.h>
|
|
#include <netinet/in_systm.h>
|
|
#include <netinet/ip.h>
|
|
#include <netinet/tcp.h>
|
|
#include <netinet/udp.h>
|
|
#include <netinet/ip_icmp.h>
|
|
#ifndef linux
|
|
#include <netinet/ip_var.h>
|
|
#include <netinet/tcpip.h>
|
|
#include <netinet/if_ether.h>
|
|
#endif
|
|
#include "ip_compat.h"
|
|
#ifdef linux
|
|
#include <linux/sockios.h>
|
|
#include "tcpip.h"
|
|
#endif
|
|
#include "ipt.h"
|
|
|
|
|
|
static u_char buf[65536]; /* 1 big packet */
|
|
|
|
extern int initdevice(), arp(), sendip();
|
|
|
|
void printpacket(ip)
|
|
ip_t *ip;
|
|
{
|
|
tcphdr_t *t;
|
|
int i, j;
|
|
|
|
t = (tcphdr_t *)((char *)ip + (ip->ip_hl << 2));
|
|
if (ip->ip_tos)
|
|
printf("tos %#x ", ip->ip_tos);
|
|
if (ip->ip_off & 0x3fff)
|
|
printf("frag @%#x ", (ip->ip_off & 0x1fff) << 3);
|
|
printf("len %d id %d ", ip->ip_len, ip->ip_id);
|
|
printf("ttl %d p %d src %s", ip->ip_ttl, ip->ip_p,
|
|
inet_ntoa(ip->ip_src));
|
|
if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
|
|
printf(",%d", t->th_sport);
|
|
printf(" dst %s", inet_ntoa(ip->ip_dst));
|
|
if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
|
|
printf(",%d", t->th_dport);
|
|
if (ip->ip_p == IPPROTO_TCP) {
|
|
printf(" seq %lu:%lu flags ",
|
|
(u_long)t->th_seq, (u_long)t->th_ack);
|
|
for (j = 0, i = 1; i < 256; i *= 2, j++)
|
|
if (t->th_flags & i)
|
|
printf("%c", "FSRPAU--"[j]);
|
|
}
|
|
putchar('\n');
|
|
}
|
|
|
|
|
|
int ip_resend(dev, mtu, r, gwip, datain)
|
|
char *dev;
|
|
int mtu;
|
|
struct in_addr gwip;
|
|
struct ipread *r;
|
|
char *datain;
|
|
{
|
|
ether_header_t *eh;
|
|
char dhost[6];
|
|
ip_t *ip;
|
|
int fd, wfd = initdevice(dev, 0, 5), len, i;
|
|
|
|
if (datain)
|
|
fd = (*r->r_open)(datain);
|
|
else
|
|
fd = (*r->r_open)("-");
|
|
|
|
if (fd < 0)
|
|
exit(-1);
|
|
|
|
ip = (struct ip *)buf;
|
|
eh = (ether_header_t *)malloc(sizeof(*eh));
|
|
|
|
bzero(&eh->ether_shost, sizeof(eh->ether_shost));
|
|
if (gwip.s_addr && (arp((char *)&gwip, dhost) == -1))
|
|
{
|
|
perror("arp");
|
|
return -2;
|
|
}
|
|
|
|
while ((i = (*r->r_readip)(buf, sizeof(buf), NULL, NULL)) > 0)
|
|
{
|
|
len = ntohs(ip->ip_len);
|
|
eh = (ether_header_t *)realloc((char *)eh, sizeof(*eh) + len);
|
|
eh->ether_type = htons((u_short)ETHERTYPE_IP);
|
|
if (!gwip.s_addr) {
|
|
if (arp((char *)&gwip,
|
|
(char *)&eh->ether_dhost) == -1) {
|
|
perror("arp");
|
|
continue;
|
|
}
|
|
} else
|
|
bcopy(dhost, (char *)&eh->ether_dhost, sizeof(dhost));
|
|
bcopy(ip, (char *)(eh + 1), len);
|
|
printpacket(ip);
|
|
|
|
if (sendip(wfd, eh, sizeof(*eh) + len) == -1)
|
|
{
|
|
perror("send_packet");
|
|
break;
|
|
}
|
|
}
|
|
(*r->r_close)();
|
|
return 0;
|
|
}
|