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[] =
  24     "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.41 2001-07-05 18:54:15 guy Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <sys/param.h>
  32 #include <sys/time.h>
  33 #include <sys/socket.h>
  34 #include <sys/file.h>
  35 #include <sys/ioctl.h>
  36
  37 struct mbuf;
  38 struct rtentry;
  39
  40 #include <netinet/in.h>
  41
  42 #include <pcap.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45
  46 #include "interface.h"
  47 #include "addrtoname.h"
  48
  49 #include "ip.h"
  50 #ifdef INET6
  51 #include "ip6.h"
  52 #endif
  53
  54 #ifndef AF_NS
  55 #define AF_NS           6               /* XEROX NS protocols */
  56 #endif
  57
  58 /*
  59  * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
  60  * 32-bit integer that specifies the family, e.g. AF_INET.
  61  *
  62  * Note here that "host" refers to the host on which the packets were
  63  * captured; that isn't necessarily *this* host.
  64  *
  65  * The OpenBSD DLT_LOOP packet header is the same, except that the integer
  66  * is in network byte order.
  67  */
  68 #define NULL_HDRLEN 4
  69
  70 static void
  71 null_print(u_int family, u_int length)
  72 {
  73         if (nflag)
  74                 printf("AF %u ", family);
  75         else {
  76                 switch (family) {
  77
  78                 case AF_INET:
  79                         printf("ip ");
  80                         break;
  81
  82 #ifdef INET6
  83                 case AF_INET6:
  84                         printf("ip6 ");
  85                         break;
  86 #endif
  87
  88                 case AF_NS:
  89                         printf("ns ");
  90                         break;
  91
  92                 default:
  93                         printf("AF %u ", family);
  94                         break;
  95                 }
  96         }
  97         printf("%d: ", length);
  98 }
  99
 100 /*
 101  * Byte-swap a 32-bit number.
 102  * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
 103  * big-endian platforms.)
 104  */
 105 #define SWAPLONG(y) \
 106 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
 107
 108 void
 109 null_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
 110 {
 111         u_int length = h->len;
 112         u_int caplen = h->caplen;
 113         const struct ip *ip;
 114         u_int family;
 115
 116         ++infodelay;
 117         ts_print(&h->ts);
 118
 119         memcpy((char *)&family, (char *)p, sizeof(family));
 120
 121         /*
 122          * This isn't necessarily in our host byte order; if this is
 123          * a DLT_LOOP capture, it's in network byte order, and if
 124          * this is a DLT_NULL capture from a machine with the opposite
 125          * byte-order, it's in the opposite byte order from ours.
 126          *
 127          * If the upper 16 bits aren't all zero, assume it's byte-swapped.
 128          */
 129         if ((family & 0xFFFF0000) != 0)
 130                 family = SWAPLONG(family);
 131
 132         /*
 133          * Some printers want to get back at the link level addresses,
 134          * and/or check that they're not walking off the end of the packet.
 135          * Rather than pass them all the way down, we set these globals.
 136          */
 137         packetp = p;
 138         snapend = p + caplen;
 139
 140         length -= NULL_HDRLEN;
 141
 142         ip = (struct ip *)(p + NULL_HDRLEN);
 143
 144         if (eflag)
 145                 null_print(family, length);
 146
 147         switch (IP_V(ip)) {
 148         case 4:
 149                 ip_print((const u_char *)ip, length);
 150                 break;
 151 #ifdef INET6
 152         case 6:
 153                 ip6_print((const u_char *)ip, length);
 154                 break;
 155 #endif /* INET6 */
 156         default:
 157                 printf("ip v%d", IP_V(ip));
 158                 break;
 159         }
 160
 161         if (xflag)
 162                 default_print((const u_char *)ip, caplen - NULL_HDRLEN);
 163         putchar('\n');
 164         --infodelay;
 165         if (infoprint)
 166                 info(0);
 167 }
 168