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/*
* 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.
*
*/
#ifndef lint
static char sccsid[] = "@(#)resend.c 1.2 8/25/95 (C)1995 Darren Reed";
#endif
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.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 */
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_sport);
if (ip->ip_p == IPPROTO_TCP) {
printf(" seq %u:%u flags ", t->th_seq, 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;
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 (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);
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;
}
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