1 /* 2 * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 * 21 * $FreeBSD$ 22 */ 23 24 #ifndef lint 25 static const char rcsid[] _U_ = 26 "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.49.2.2 2003/11/16 08:51:36 guy Exp $ (LBL)"; 27 #endif 28 29 #ifdef HAVE_CONFIG_H 30 #include "config.h" 31 #endif 32 33 #include <tcpdump-stdinc.h> 34 35 #include <pcap.h> 36 #include <stdio.h> 37 #include <string.h> 38 39 #include "interface.h" 40 #include "addrtoname.h" 41 42 #include "ip.h" 43 #ifdef INET6 44 #include "ip6.h" 45 #endif 46 47 /* 48 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order 49 * 32-bit integer that specifies the family, e.g. AF_INET. 50 * 51 * Note here that "host" refers to the host on which the packets were 52 * captured; that isn't necessarily *this* host. 53 * 54 * The OpenBSD DLT_LOOP packet header is the same, except that the integer 55 * is in network byte order. 56 */ 57 #define NULL_HDRLEN 4 58 59 /* 60 * BSD AF_ values. 61 * 62 * Unfortunately, the BSDs don't all use the same value for AF_INET6, 63 * so, because we want to be able to read captures from all of the BSDs, 64 * we check for all of them. 65 */ 66 #define BSD_AF_INET 2 67 #define BSD_AF_NS 6 /* XEROX NS protocols */ 68 #define BSD_AF_ISO 7 69 #define BSD_AF_APPLETALK 16 70 #define BSD_AF_IPX 23 71 #define BSD_AF_INET6_BSD 24 /* OpenBSD (and probably NetBSD), BSD/OS */ 72 #define BSD_AF_INET6_FREEBSD 28 73 #define BSD_AF_INET6_DARWIN 30 74 75 static void 76 null_print(u_int family, u_int length) 77 { 78 if (nflag) 79 printf("AF %u ", family); 80 else { 81 switch (family) { 82 83 case BSD_AF_INET: 84 printf("ip "); 85 break; 86 87 #ifdef INET6 88 case BSD_AF_INET6_BSD: 89 case BSD_AF_INET6_FREEBSD: 90 case BSD_AF_INET6_DARWIN: 91 printf("ip6 "); 92 break; 93 #endif 94 95 case BSD_AF_NS: 96 printf("ns "); 97 break; 98 99 case BSD_AF_ISO: 100 printf("osi "); 101 break; 102 103 case BSD_AF_APPLETALK: 104 printf("atalk "); 105 break; 106 107 case BSD_AF_IPX: 108 printf("ipx "); 109 break; 110 111 default: 112 printf("AF %u ", family); 113 break; 114 } 115 } 116 printf("%d: ", length); 117 } 118 119 /* 120 * Byte-swap a 32-bit number. 121 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on 122 * big-endian platforms.) 123 */ 124 #define SWAPLONG(y) \ 125 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) 126 127 /* 128 * This is the top level routine of the printer. 'p' points 129 * to the ether header of the packet, 'h->ts' is the timestamp, 130 * 'h->length' is the length of the packet off the wire, and 'h->caplen' 131 * is the number of bytes actually captured. 132 */ 133 u_int 134 null_if_print(const struct pcap_pkthdr *h, const u_char *p) 135 { 136 u_int length = h->len; 137 u_int caplen = h->caplen; 138 u_int family; 139 140 if (caplen < NULL_HDRLEN) { 141 printf("[|null]"); 142 return (NULL_HDRLEN); 143 } 144 145 memcpy((char *)&family, (char *)p, sizeof(family)); 146 147 /* 148 * This isn't necessarily in our host byte order; if this is 149 * a DLT_LOOP capture, it's in network byte order, and if 150 * this is a DLT_NULL capture from a machine with the opposite 151 * byte-order, it's in the opposite byte order from ours. 152 * 153 * If the upper 16 bits aren't all zero, assume it's byte-swapped. 154 */ 155 if ((family & 0xFFFF0000) != 0) 156 family = SWAPLONG(family); 157 158 length -= NULL_HDRLEN; 159 caplen -= NULL_HDRLEN; 160 p += NULL_HDRLEN; 161 162 if (eflag) 163 null_print(family, length); 164 165 switch (family) { 166 167 case BSD_AF_INET: 168 ip_print(p, length); 169 break; 170 171 #ifdef INET6 172 case BSD_AF_INET6_BSD: 173 case BSD_AF_INET6_FREEBSD: 174 case BSD_AF_INET6_DARWIN: 175 ip6_print(p, length); 176 break; 177 #endif 178 179 case BSD_AF_ISO: 180 isoclns_print(p, length, caplen); 181 break; 182 183 case BSD_AF_APPLETALK: 184 atalk_print(p, length); 185 break; 186 187 case BSD_AF_IPX: 188 ipx_print(p, length); 189 break; 190 191 default: 192 /* unknown AF_ value */ 193 if (!eflag) 194 null_print(family, length + NULL_HDRLEN); 195 if (!xflag && !qflag) 196 default_print(p, caplen); 197 } 198 199 return (NULL_HDRLEN); 200 } 201 202