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