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 1.2.2.1 2000/01/11 06:58:26 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 } 143 144