The Tcpdump Group git mirrors - tcpdump/blob - print-mobile.c

   1 /*      $NetBSD: print-mobile.c,v 1.2 1998/09/30 08:57:01 hwr Exp $ */
   2
   3 /*
   4  * (c) 1998 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Heiko W.Rupp <hwr@pilhuhn.de>
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *        This product includes software developed by the NetBSD
  21  *        Foundation, Inc. and its contributors.
  22  * 4. Neither the name of The NetBSD Foundation nor the names of its
  23  *    contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  * POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 #ifdef HAVE_CONFIG_H
  40 #include "config.h"
  41 #endif
  42
  43 #ifndef lint
  44 static const char rcsid[] =
  45      "@(#) $Header: /tcpdump/master/tcpdump/print-mobile.c,v 1.5 2000-09-29 04:58:43 guy Exp $";
  46 #endif
  47
  48 #include <sys/param.h>
  49 #include <sys/time.h>
  50 #include <sys/uio.h>
  51 #include <sys/socket.h>
  52
  53 #include <netinet/in.h>
  54
  55 #include <netdb.h>
  56 #include <stdio.h>
  57
  58 #include "interface.h"
  59 #include "addrtoname.h"
  60 #include "extract.h"            /* must come after interface.h */
  61
  62 #define MOBILE_SIZE (8)
  63
  64 struct mobile_ip {
  65         u_int16_t proto;
  66         u_int16_t hcheck;
  67         u_int32_t odst;
  68         u_int32_t osrc;
  69 };
  70
  71 #define OSRC_PRES       0x0080  /* old source is present */
  72
  73 static u_int16_t mob_in_cksum(u_short *p, int len);
  74
  75 /*
  76  * Deencapsulate and print a mobile-tunneled IP datagram
  77  */
  78 void
  79 mobile_print(const u_char *bp, u_int length)
  80 {
  81         const u_char *cp = bp +8 ;
  82         const struct mobile_ip *mob;
  83         u_short proto,crc;
  84         u_char osp =0;                  /* old source address present */
  85
  86         mob = (const struct mobile_ip *)bp;
  87
  88         if (length < MOBILE_SIZE) {
  89                 fputs("[|mobile]", stdout);
  90                 return;
  91         }
  92
  93         proto = EXTRACT_16BITS(&mob->proto);
  94         crc =  EXTRACT_16BITS(&mob->hcheck);
  95         if (proto & OSRC_PRES) {
  96                 osp=1;
  97                 cp +=4 ;
  98         }
  99
 100         if (osp)  {
 101                 fputs("[S] ",stdout);
 102                 if (vflag)
 103                         (void)printf("%s ",ipaddr_string(&mob->osrc));
 104         } else {
 105                 fputs("[] ",stdout);
 106         }
 107         if (vflag) {
 108                 (void)printf("> %s ",ipaddr_string(&mob->odst));
 109                 (void)printf("(oproto=%d)",proto>>8);
 110         }
 111         if (mob_in_cksum((u_short *)mob, osp ? 12 : 8)!=0) {
 112                 (void)printf(" (bad checksum %d)",crc);
 113         }
 114
 115         return;
 116 }
 117
 118 static u_int16_t mob_in_cksum(u_short *p, int len)
 119 {
 120         u_int32_t sum = 0;
 121         int nwords = len >> 1;
 122
 123         while (nwords-- != 0)
 124                 sum += *p++;
 125
 126         if (len & 1) {
 127                 union {
 128                         u_int16_t w;
 129                         u_int8_t c[2];
 130                 } u;
 131                 u.c[0] = *(u_char *)p;
 132                 u.c[1] = 0;
 133                 sum += u.w;
 134         }
 135
 136         /* end-around-carry */
 137         sum = (sum >> 16) + (sum & 0xffff);
 138         sum += (sum >> 16);
 139         return (~sum);
 140 }
 141