contrib/ipfilter/ipsend/resend.c

   1 /*
   2  * resend.c (C) 1995-1998 Darren Reed
   3  *
   4  * This was written to test what size TCP fragments would get through
   5  * various TCP/IP packet filters, as used in IP firewalls.  In certain
   6  * conditions, enough of the TCP header is missing for unpredictable
   7  * results unless the filter is aware that this can happen.
   8  *
   9  * See the IPFILTER.LICENCE file for details on licencing.
  10  */
  11 #if defined(__sgi) && (IRIX > 602)
  12 # include <sys/ptimers.h>
  13 #endif
  14 #include <stdio.h>
  15 #include <netdb.h>
  16 #include <string.h>
  17 #include <stdlib.h>
  18 #include <unistd.h>
  19 #include <sys/types.h>
  20 #include <sys/time.h>
  21 #include <sys/socket.h>
  22 #include <net/if.h>
  23 #include <netinet/in.h>
  24 #include <arpa/inet.h>
  25 #include <netinet/in_systm.h>
  26 #include <netinet/ip.h>
  27 #include <netinet/tcp.h>
  28 #include <netinet/udp.h>
  29 #include <netinet/ip_icmp.h>
  30 #ifndef linux
  31 # include <netinet/ip_var.h>
  32 # include <netinet/if_ether.h>
  33 # if __FreeBSD_version >= 300000
  34 #  include <net/if_var.h>
  35 # endif
  36 #endif
  37 #include "ipsend.h"
  38
  39 #if !defined(lint)
  40 static const char sccsid[] = "@(#)resend.c      1.3 1/11/96 (C)1995 Darren Reed";
  41 static const char rcsid[] = "@(#)$Id: resend.c,v 2.1.4.5 2002/12/06 11:40:36 darrenr Exp $";
  42 #endif
  43
  44
  45 extern  int     opts;
  46
  47 static  u_char  pbuf[65536];    /* 1 big packet */
  48 void    printpacket __P((ip_t *));
  49
  50
  51 void printpacket(ip)
  52 ip_t    *ip;
  53 {
  54         tcphdr_t *t;
  55         int i, j;
  56
  57         t = (tcphdr_t *)((char *)ip + (ip->ip_hl << 2));
  58         if (ip->ip_tos)
  59                 printf("tos %#x ", ip->ip_tos);
  60         if (ip->ip_off & 0x3fff)
  61                 printf("frag @%#x ", (ip->ip_off & 0x1fff) << 3);
  62         printf("len %d id %d ", ip->ip_len, ip->ip_id);
  63         printf("ttl %d p %d src %s", ip->ip_ttl, ip->ip_p,
  64                 inet_ntoa(ip->ip_src));
  65         if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
  66                 printf(",%d", t->th_sport);
  67         printf(" dst %s", inet_ntoa(ip->ip_dst));
  68         if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
  69                 printf(",%d", t->th_dport);
  70         if (ip->ip_p == IPPROTO_TCP) {
  71                 printf(" seq %lu:%lu flags ",
  72                         (u_long)t->th_seq, (u_long)t->th_ack);
  73                 for (j = 0, i = 1; i < 256; i *= 2, j++)
  74                         if (t->th_flags & i)
  75                                 printf("%c", "FSRPAU--"[j]);
  76         }
  77         putchar('\n');
  78 }
  79
  80
  81 int     ip_resend(dev, mtu, r, gwip, datain)
  82 char    *dev;
  83 int     mtu;
  84 struct  in_addr gwip;
  85 struct  ipread  *r;
  86 char    *datain;
  87 {
  88         ether_header_t  *eh;
  89         char    dhost[6];
  90         ip_t    *ip;
  91         int     fd, wfd = initdevice(dev, 0, 5), len, i;
  92
  93         if (datain)
  94                 fd = (*r->r_open)(datain);
  95         else
  96                 fd = (*r->r_open)("-");
  97
  98         if (fd < 0)
  99                 exit(-1);
 100
 101         ip = (struct ip *)pbuf;
 102         eh = (ether_header_t *)malloc(sizeof(*eh));
 103         if(!eh)
 104             {
 105                 perror("malloc failed");
 106                 return -2;
 107             }
 108
 109         bzero((char *)A_A eh->ether_shost, sizeof(eh->ether_shost));
 110         if (gwip.s_addr && (arp((char *)&gwip, dhost) == -1))
 111             {
 112                 perror("arp");
 113                 return -2;
 114             }
 115
 116         while ((i = (*r->r_readip)((char *)pbuf, sizeof(pbuf), NULL, NULL)) > 0)
 117             {
 118                 if (!(opts & OPT_RAW)) {
 119                         len = ntohs(ip->ip_len);
 120                         eh = (ether_header_t *)realloc((char *)eh, sizeof(*eh) + len);
 121                         eh->ether_type = htons((u_short)ETHERTYPE_IP);
 122                         if (!gwip.s_addr) {
 123                                 if (arp((char *)&gwip,
 124                                         (char *)A_A eh->ether_dhost) == -1) {
 125                                         perror("arp");
 126                                         continue;
 127                                 }
 128                         } else
 129                                 bcopy(dhost, (char *)A_A eh->ether_dhost,
 130                                       sizeof(dhost));
 131                         if (!ip->ip_sum)
 132                                 ip->ip_sum = chksum((u_short *)ip,
 133                                                     ip->ip_hl << 2);
 134                         bcopy(ip, (char *)(eh + 1), len);
 135                         len += sizeof(*eh);
 136                         printpacket(ip);
 137                 } else {
 138                         eh = (ether_header_t *)pbuf;
 139                         len = i;
 140                 }
 141
 142                 if (sendip(wfd, (char *)eh, len) == -1)
 143                     {
 144                         perror("send_packet");
 145                         break;
 146                     }
 147             }
 148         (*r->r_close)();
 149         return 0;
 150 }