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
23static const char rcsid[] _U_ =
24    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.53.2.4 2007/02/26 13:31:33 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#include "af.h"
40
41#include "ip.h"
42#ifdef INET6
43#include "ip6.h"
44#endif
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/*
60 * Byte-swap a 32-bit number.
61 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
62 * big-endian platforms.)
63 */
64#define	SWAPLONG(y) \
65((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
66
67static inline void
68null_hdr_print(u_int family, u_int length)
69{
70	if (!qflag) {
71		(void)printf("AF %s (%u)",
72			tok2str(bsd_af_values,"Unknown",family),family);
73	} else {
74		(void)printf("%s",
75			tok2str(bsd_af_values,"Unknown AF %u",family));
76	}
77
78	(void)printf(", length %u: ", length);
79}
80
81/*
82 * This is the top level routine of the printer.  'p' points
83 * to the ether header of the packet, 'h->ts' is the timestamp,
84 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
85 * is the number of bytes actually captured.
86 */
87u_int
88null_if_print(const struct pcap_pkthdr *h, const u_char *p)
89{
90	u_int length = h->len;
91	u_int caplen = h->caplen;
92	u_int family;
93
94	if (caplen < NULL_HDRLEN) {
95		printf("[|null]");
96		return (NULL_HDRLEN);
97	}
98
99	memcpy((char *)&family, (char *)p, sizeof(family));
100
101	/*
102	 * This isn't necessarily in our host byte order; if this is
103	 * a DLT_LOOP capture, it's in network byte order, and if
104	 * this is a DLT_NULL capture from a machine with the opposite
105	 * byte-order, it's in the opposite byte order from ours.
106	 *
107	 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
108	 */
109	if ((family & 0xFFFF0000) != 0)
110		family = SWAPLONG(family);
111
112	if (eflag)
113		null_hdr_print(family, length);
114
115	length -= NULL_HDRLEN;
116	caplen -= NULL_HDRLEN;
117	p += NULL_HDRLEN;
118
119	switch (family) {
120
121	case BSD_AFNUM_INET:
122		ip_print(gndo, p, length);
123		break;
124
125#ifdef INET6
126	case BSD_AFNUM_INET6_BSD:
127	case BSD_AFNUM_INET6_FREEBSD:
128	case BSD_AFNUM_INET6_DARWIN:
129		ip6_print(p, length);
130		break;
131#endif
132
133	case BSD_AFNUM_ISO:
134		isoclns_print(p, length, caplen);
135		break;
136
137	case BSD_AFNUM_APPLETALK:
138		atalk_print(p, length);
139		break;
140
141	case BSD_AFNUM_IPX:
142		ipx_print(p, length);
143		break;
144
145	default:
146		/* unknown AF_ value */
147		if (!eflag)
148			null_hdr_print(family, length + NULL_HDRLEN);
149		if (!suppress_default_print)
150			default_print(p, caplen);
151	}
152
153	return (NULL_HDRLEN);
154}
155
156/*
157 * Local Variables:
158 * c-style: whitesmith
159 * c-basic-offset: 8
160 * End:
161 */
162