The Tcpdump Group git mirrors - tcpdump/blob - print-null.c

   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
  22 #ifndef lint
  23 static const char rcsid[] _U_ =
  24     "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.49.2.2 2003-11-16 08:51:36 guy Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <tcpdump-stdinc.h>
  32
  33 #include <pcap.h>
  34 #include <stdio.h>
  35 #include <string.h>
  36
  37 #include "interface.h"
  38 #include "addrtoname.h"
  39
  40 #include "ip.h"
  41 #ifdef INET6
  42 #include "ip6.h"
  43 #endif
  44
  45 /*
  46  * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
  47  * 32-bit integer that specifies the family, e.g. AF_INET.
  48  *
  49  * Note here that "host" refers to the host on which the packets were
  50  * captured; that isn't necessarily *this* host.
  51  *
  52  * The OpenBSD DLT_LOOP packet header is the same, except that the integer
  53  * is in network byte order.
  54  */
  55 #define NULL_HDRLEN 4
  56
  57 /*
  58  * BSD AF_ values.
  59  *
  60  * Unfortunately, the BSDs don't all use the same value for AF_INET6,
  61  * so, because we want to be able to read captures from all of the BSDs,
  62  * we check for all of them.
  63  */
  64 #define BSD_AF_INET             2
  65 #define BSD_AF_NS               6               /* XEROX NS protocols */
  66 #define BSD_AF_ISO              7
  67 #define BSD_AF_APPLETALK        16
  68 #define BSD_AF_IPX              23
  69 #define BSD_AF_INET6_BSD        24      /* OpenBSD (and probably NetBSD), BSD/OS */
  70 #define BSD_AF_INET6_FREEBSD    28
  71 #define BSD_AF_INET6_DARWIN     30
  72
  73 static void
  74 null_print(u_int family, u_int length)
  75 {
  76         if (nflag)
  77                 printf("AF %u ", family);
  78         else {
  79                 switch (family) {
  80
  81                 case BSD_AF_INET:
  82                         printf("ip ");
  83                         break;
  84
  85 #ifdef INET6
  86                 case BSD_AF_INET6_BSD:
  87                 case BSD_AF_INET6_FREEBSD:
  88                 case BSD_AF_INET6_DARWIN:
  89                         printf("ip6 ");
  90                         break;
  91 #endif
  92
  93                 case BSD_AF_NS:
  94                         printf("ns ");
  95                         break;
  96
  97                 case BSD_AF_ISO:
  98                         printf("osi ");
  99                         break;
 100
 101                 case BSD_AF_APPLETALK:
 102                         printf("atalk ");
 103                         break;
 104
 105                 case BSD_AF_IPX:
 106                         printf("ipx ");
 107                         break;
 108
 109                 default:
 110                         printf("AF %u ", family);
 111                         break;
 112                 }
 113         }
 114         printf("%d: ", length);
 115 }
 116
 117 /*
 118  * Byte-swap a 32-bit number.
 119  * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
 120  * big-endian platforms.)
 121  */
 122 #define SWAPLONG(y) \
 123 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
 124
 125 /*
 126  * This is the top level routine of the printer.  'p' points
 127  * to the ether header of the packet, 'h->ts' is the timestamp,
 128  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 129  * is the number of bytes actually captured.
 130  */
 131 u_int
 132 null_if_print(const struct pcap_pkthdr *h, const u_char *p)
 133 {
 134         u_int length = h->len;
 135         u_int caplen = h->caplen;
 136         u_int family;
 137
 138         if (caplen < NULL_HDRLEN) {
 139                 printf("[|null]");
 140                 return (NULL_HDRLEN);
 141         }
 142
 143         memcpy((char *)&family, (char *)p, sizeof(family));
 144
 145         /*
 146          * This isn't necessarily in our host byte order; if this is
 147          * a DLT_LOOP capture, it's in network byte order, and if
 148          * this is a DLT_NULL capture from a machine with the opposite
 149          * byte-order, it's in the opposite byte order from ours.
 150          *
 151          * If the upper 16 bits aren't all zero, assume it's byte-swapped.
 152          */
 153         if ((family & 0xFFFF0000) != 0)
 154                 family = SWAPLONG(family);
 155
 156         length -= NULL_HDRLEN;
 157         caplen -= NULL_HDRLEN;
 158         p += NULL_HDRLEN;
 159
 160         if (eflag)
 161                 null_print(family, length);
 162
 163         switch (family) {
 164
 165         case BSD_AF_INET:
 166                 ip_print(p, length);
 167                 break;
 168
 169 #ifdef INET6
 170         case BSD_AF_INET6_BSD:
 171         case BSD_AF_INET6_FREEBSD:
 172         case BSD_AF_INET6_DARWIN:
 173                 ip6_print(p, length);
 174                 break;
 175 #endif
 176
 177         case BSD_AF_ISO:
 178                 isoclns_print(p, length, caplen);
 179                 break;
 180
 181         case BSD_AF_APPLETALK:
 182                 atalk_print(p, length);
 183                 break;
 184
 185         case BSD_AF_IPX:
 186                 ipx_print(p, length);
 187                 break;
 188
 189         default:
 190                 /* unknown AF_ value */
 191                 if (!eflag)
 192                         null_print(family, length + NULL_HDRLEN);
 193                 if (!xflag && !qflag)
 194                         default_print(p, caplen);
 195         }
 196
 197         return (NULL_HDRLEN);
 198 }
 199