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 #if 0
  40 #include <sys/cdefs.h>
  41 #ifndef lint
  42 __RCSID("$NetBSD: print-mobile.c,v 1.2 1998/09/30 08:57:01 hwr Exp $");
  43 #endif
  44 #endif
  45
  46 #ifdef HAVE_CONFIG_H
  47 #include "config.h"
  48 #endif
  49
  50 #include <sys/param.h>
  51 #include <sys/time.h>
  52 #include <sys/uio.h>
  53 #include <sys/socket.h>
  54
  55 #include <netinet/in.h>
  56 #include <netinet/in_systm.h>
  57 #include <netinet/ip.h>
  58
  59 #include <netdb.h>
  60 #include <stdio.h>
  61
  62 #include "interface.h"
  63 #include "addrtoname.h"
  64 #include "extract.h"            /* must come after interface.h */
  65
  66 #define MOBILE_SIZE (8)
  67
  68 struct mobile_ip {
  69         u_int16_t proto;
  70         u_int16_t hcheck;
  71         u_int32_t odst;
  72         u_int32_t osrc;
  73 };
  74
  75 #define OSRC_PRES       0x0080  /* old source is present */
  76
  77 static u_int16_t mob_in_cksum(u_short *p, int len);
  78
  79 /*
  80  * Deencapsulate and print a mobile-tunneled IP datagram
  81  */
  82 void
  83 mobile_print(const u_char *bp, u_int length)
  84 {
  85         const u_char *cp = bp +8 ;
  86         const struct mobile_ip *mob;
  87         u_short proto,crc;
  88         u_char osp =0;                  /* old source address present */
  89
  90         mob = (const struct mobile_ip *)bp;
  91
  92         if (length < MOBILE_SIZE) {
  93                 fputs("[|mobile]", stdout);
  94                 return;
  95         }
  96
  97         proto = EXTRACT_16BITS(&mob->proto);
  98         crc =  EXTRACT_16BITS(&mob->hcheck);
  99         if (proto & OSRC_PRES) {
 100                 osp=1;
 101                 cp +=4 ;
 102         }
 103
 104         if (osp)  {
 105                 fputs("[S] ",stdout);
 106                 if (vflag)
 107                         (void)printf("%s ",ipaddr_string(&mob->osrc));
 108         } else {
 109                 fputs("[] ",stdout);
 110         }
 111         if (vflag) {
 112                 (void)printf("> %s ",ipaddr_string(&mob->odst));
 113                 (void)printf("(oproto=%d)",proto>>8);
 114         }
 115         if (mob_in_cksum((u_short *)mob, osp ? 12 : 8)!=0) {
 116                 (void)printf(" (bad checksum %d)",crc);
 117         }
 118
 119         return;
 120 }
 121
 122 static u_int16_t mob_in_cksum(u_short *p, int len)
 123 {
 124         u_int32_t sum = 0;
 125         int nwords = len >> 1;
 126
 127         while (nwords-- != 0)
 128                 sum += *p++;
 129
 130         if (len & 1) {
 131                 union {
 132                         u_int16_t w;
 133                         u_int8_t c[2];
 134                 } u;
 135                 u.c[0] = *(u_char *)p;
 136                 u.c[1] = 0;
 137                 sum += u.w;
 138         }
 139
 140         /* end-around-carry */
 141         sum = (sum >> 16) + (sum & 0xffff);
 142         sum += (sum >> 16);
 143         return (~sum);
 144 }
 145