contrib/tcpdump/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 1.57 2006-03-23 14:58:44 hannes 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 #include "af.h"
  45
  46 /*
  47  * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
  48  * 32-bit integer that specifies the family, e.g. AF_INET.
  49  *
  50  * Note here that "host" refers to the host on which the packets were
  51  * captured; that isn't necessarily *this* host.
  52  *
  53  * The OpenBSD DLT_LOOP packet header is the same, except that the integer
  54  * is in network byte order.
  55  */
  56 #define NULL_HDRLEN 4
  57
  58 /*
  59  * Byte-swap a 32-bit number.
  60  * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
  61  * big-endian platforms.)
  62  */
  63 #define SWAPLONG(y) \
  64 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
  65
  66 static inline void
  67 null_hdr_print(u_int family, u_int length)
  68 {
  69         if (!qflag) {
  70                 (void)printf("AF %s (%u)",
  71                         tok2str(bsd_af_values,"Unknown",family),family);
  72         } else {
  73                 (void)printf("%s",
  74                         tok2str(bsd_af_values,"Unknown AF %u",family));
  75         }
  76
  77         (void)printf(", length %u: ", length);
  78 }
  79
  80 /*
  81  * This is the top level routine of the printer.  'p' points
  82  * to the ether header of the packet, 'h->ts' is the timestamp,
  83  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  84  * is the number of bytes actually captured.
  85  */
  86 u_int
  87 null_if_print(const struct pcap_pkthdr *h, const u_char *p)
  88 {
  89         u_int length = h->len;
  90         u_int caplen = h->caplen;
  91         u_int family;
  92
  93         if (caplen < NULL_HDRLEN) {
  94                 printf("[|null]");
  95                 return (NULL_HDRLEN);
  96         }
  97
  98         memcpy((char *)&family, (char *)p, sizeof(family));
  99
 100         /*
 101          * This isn't necessarily in our host byte order; if this is
 102          * a DLT_LOOP capture, it's in network byte order, and if
 103          * this is a DLT_NULL capture from a machine with the opposite
 104          * byte-order, it's in the opposite byte order from ours.
 105          *
 106          * If the upper 16 bits aren't all zero, assume it's byte-swapped.
 107          */
 108         if ((family & 0xFFFF0000) != 0)
 109                 family = SWAPLONG(family);
 110
 111         if (eflag)
 112                 null_hdr_print(family, length);
 113
 114         length -= NULL_HDRLEN;
 115         caplen -= NULL_HDRLEN;
 116         p += NULL_HDRLEN;
 117
 118         switch (family) {
 119
 120         case BSD_AFNUM_INET:
 121                 ip_print(gndo, p, length);
 122                 break;
 123
 124 #ifdef INET6
 125         case BSD_AFNUM_INET6_BSD:
 126         case BSD_AFNUM_INET6_FREEBSD:
 127         case BSD_AFNUM_INET6_DARWIN:
 128                 ip6_print(p, length);
 129                 break;
 130 #endif
 131
 132         case BSD_AFNUM_ISO:
 133                 isoclns_print(p, length, caplen);
 134                 break;
 135
 136         case BSD_AFNUM_APPLETALK:
 137                 atalk_print(p, length);
 138                 break;
 139
 140         case BSD_AFNUM_IPX:
 141                 ipx_print(p, length);
 142                 break;
 143
 144         default:
 145                 /* unknown AF_ value */
 146                 if (!eflag)
 147                         null_hdr_print(family, length + NULL_HDRLEN);
 148                 if (!suppress_default_print)
 149                         default_print(p, caplen);
 150         }
 151
 152         return (NULL_HDRLEN);
 153 }
 154
 155 /*
 156  * Local Variables:
 157  * c-style: whitesmith
 158  * c-basic-offset: 8
 159  * End:
 160  */