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 } 141 142