dist/tcpdump/print-null.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that: (1) source code distributions
   9  * retain the above copyright notice and this paragraph in its entirety, (2)
  10  * distributions including binary code include the above copyright notice and
  11  * this paragraph in its entirety in the documentation or other materials
  12  * provided with the distribution, and (3) all advertising materials mentioning
  13  * features or use of this software display the following acknowledgement:
  14  * ``This product includes software developed by the University of California,
  15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  16  * the University nor the names of its contributors may be used to endorse
  17  * or promote products derived from this software without specific prior
  18  * written permission.
  19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  22  */
  23
  24 #include <sys/cdefs.h>
  25 #ifndef lint
  26 #if 0
  27 static const char rcsid[] _U_ =
  28     "@(#) Header: /tcpdump/master/tcpdump/print-null.c,v 1.53.2.4 2007/02/26 13:31:33 hannes Exp (LBL)";
  29 #else
  30 __RCSID("$NetBSD: tcpdump2rcsid.ex,v 1.1 2001/06/25 20:09:58 itojun Exp $");
  31 #endif
  32 #endif
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include "config.h"
  36 #endif
  37
  38 #include <tcpdump-stdinc.h>
  39
  40 #include <pcap.h>
  41 #include <stdio.h>
  42 #include <string.h>
  43
  44 #include "interface.h"
  45 #include "addrtoname.h"
  46 #include "af.h"
  47
  48 #include "ip.h"
  49 #ifdef INET6
  50 #include "ip6.h"
  51 #endif
  52
  53 /*
  54  * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
  55  * 32-bit integer that specifies the family, e.g. AF_INET.
  56  *
  57  * Note here that "host" refers to the host on which the packets were
  58  * captured; that isn't necessarily *this* host.
  59  *
  60  * The OpenBSD DLT_LOOP packet header is the same, except that the integer
  61  * is in network byte order.
  62  */
  63 #define NULL_HDRLEN 4
  64
  65
  66 /*
  67  * Byte-swap a 32-bit number.
  68  * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
  69  * big-endian platforms.)
  70  */
  71 #define SWAPLONG(y) \
  72 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
  73
  74 static inline void
  75 null_hdr_print(u_int family, u_int length)
  76 {
  77         if (!qflag) {
  78                 (void)printf("AF %s (%u)",
  79                         tok2str(bsd_af_values,"Unknown",family),family);
  80         } else {
  81                 (void)printf("%s",
  82                         tok2str(bsd_af_values,"Unknown AF %u",family));
  83         }
  84
  85         (void)printf(", length %u: ", length);
  86 }
  87
  88 /*
  89  * This is the top level routine of the printer.  'p' points
  90  * to the ether header of the packet, 'h->ts' is the timestamp,
  91  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  92  * is the number of bytes actually captured.
  93  */
  94 u_int
  95 null_if_print(const struct pcap_pkthdr *h, const u_char *p)
  96 {
  97         u_int length = h->len;
  98         u_int caplen = h->caplen;
  99         u_int family;
 100
 101         if (caplen < NULL_HDRLEN) {
 102                 printf("[|null]");
 103                 return (NULL_HDRLEN);
 104         }
 105
 106         memcpy((char *)&family, (char *)p, sizeof(family));
 107
 108         /*
 109          * This isn't necessarily in our host byte order; if this is
 110          * a DLT_LOOP capture, it's in network byte order, and if
 111          * this is a DLT_NULL capture from a machine with the opposite
 112          * byte-order, it's in the opposite byte order from ours.
 113          *
 114          * If the upper 16 bits aren't all zero, assume it's byte-swapped.
 115          */
 116         if ((family & 0xFFFF0000) != 0)
 117                 family = SWAPLONG(family);
 118
 119         if (eflag)
 120                 null_hdr_print(family, length);
 121
 122         length -= NULL_HDRLEN;
 123         caplen -= NULL_HDRLEN;
 124         p += NULL_HDRLEN;
 125
 126         switch (family) {
 127
 128         case BSD_AFNUM_INET:
 129                 ip_print(gndo, p, length);
 130                 break;
 131
 132 #ifdef INET6
 133         case BSD_AFNUM_INET6_BSD:
 134         case BSD_AFNUM_INET6_FREEBSD:
 135         case BSD_AFNUM_INET6_DARWIN:
 136                 ip6_print(p, length);
 137                 break;
 138 #endif
 139
 140         case BSD_AFNUM_ISO:
 141                 isoclns_print(p, length, caplen);
 142                 break;
 143
 144         case BSD_AFNUM_APPLETALK:
 145                 atalk_print(p, length);
 146                 break;
 147
 148         case BSD_AFNUM_IPX:
 149                 ipx_print(p, length);
 150                 break;
 151
 152         default:
 153                 /* unknown AF_ value */
 154                 if (!eflag)
 155                         null_hdr_print(family, length + NULL_HDRLEN);
 156                 if (!suppress_default_print)
 157                         default_print(p, caplen);
 158         }
 159
 160         return (NULL_HDRLEN);
 161 }
 162
 163 /*
 164  * Local Variables:
 165  * c-style: whitesmith
 166  * c-basic-offset: 8
 167  * End:
 168  */