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 1.3 2000-01-09 21:34:18 fenner 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 #include <netinet/in_systm.h>
  55 #include <netinet/ip.h>
  56
  57 #include <netdb.h>
  58 #include <stdio.h>
  59
  60 #include "interface.h"
  61 #include "addrtoname.h"
  62 #include "extract.h"            /* must come after interface.h */
  63
  64 #define MOBILE_SIZE (8)
  65
  66 struct mobile_ip {
  67         u_int16_t proto;
  68         u_int16_t hcheck;
  69         u_int32_t odst;
  70         u_int32_t osrc;
  71 };
  72
  73 #define OSRC_PRES       0x0080  /* old source is present */
  74
  75 static u_int16_t mob_in_cksum(u_short *p, int len);
  76
  77 /*
  78  * Deencapsulate and print a mobile-tunneled IP datagram
  79  */
  80 void
  81 mobile_print(const u_char *bp, u_int length)
  82 {
  83         const u_char *cp = bp +8 ;
  84         const struct mobile_ip *mob;
  85         u_short proto,crc;
  86         u_char osp =0;                  /* old source address present */
  87
  88         mob = (const struct mobile_ip *)bp;
  89
  90         if (length < MOBILE_SIZE) {
  91                 fputs("[|mobile]", stdout);
  92                 return;
  93         }
  94
  95         proto = EXTRACT_16BITS(&mob->proto);
  96         crc =  EXTRACT_16BITS(&mob->hcheck);
  97         if (proto & OSRC_PRES) {
  98                 osp=1;
  99                 cp +=4 ;
 100         }
 101
 102         if (osp)  {
 103                 fputs("[S] ",stdout);
 104                 if (vflag)
 105                         (void)printf("%s ",ipaddr_string(&mob->osrc));
 106         } else {
 107                 fputs("[] ",stdout);
 108         }
 109         if (vflag) {
 110                 (void)printf("> %s ",ipaddr_string(&mob->odst));
 111                 (void)printf("(oproto=%d)",proto>>8);
 112         }
 113         if (mob_in_cksum((u_short *)mob, osp ? 12 : 8)!=0) {
 114                 (void)printf(" (bad checksum %d)",crc);
 115         }
 116
 117         return;
 118 }
 119
 120 static u_int16_t mob_in_cksum(u_short *p, int len)
 121 {
 122         u_int32_t sum = 0;
 123         int nwords = len >> 1;
 124
 125         while (nwords-- != 0)
 126                 sum += *p++;
 127
 128         if (len & 1) {
 129                 union {
 130                         u_int16_t w;
 131                         u_int8_t c[2];
 132                 } u;
 133                 u.c[0] = *(u_char *)p;
 134                 u.c[1] = 0;
 135                 sum += u.w;
 136         }
 137
 138         /* end-around-carry */
 139         sum = (sum >> 16) + (sum & 0xffff);
 140         sum += (sum >> 16);
 141         return (~sum);
 142 }
 143