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 * $FreeBSD$
22 */
23
24#ifndef lint
25static const char rcsid[] _U_ =
26    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.57 2006-03-23 14:58:44 hannes Exp $ (LBL)";
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <tcpdump-stdinc.h>
34
35#include <pcap.h>
36#include <stdio.h>
37#include <string.h>
38
39#include "interface.h"
40#include "addrtoname.h"
41
42#include "ip.h"
43#ifdef INET6
44#include "ip6.h"
45#endif
46#include "af.h"
47
48/*
49 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
50 * 32-bit integer that specifies the family, e.g. AF_INET.
51 *
52 * Note here that "host" refers to the host on which the packets were
53 * captured; that isn't necessarily *this* host.
54 *
55 * The OpenBSD DLT_LOOP packet header is the same, except that the integer
56 * is in network byte order.
57 */
58#define	NULL_HDRLEN 4
59
60/*
61 * Byte-swap a 32-bit number.
62 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
63 * big-endian platforms.)
64 */
65#define	SWAPLONG(y) \
66((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
67
68static inline void
69null_hdr_print(u_int family, u_int length)
70{
71	if (!qflag) {
72		(void)printf("AF %s (%u)",
73			tok2str(bsd_af_values,"Unknown",family),family);
74	} else {
75		(void)printf("%s",
76			tok2str(bsd_af_values,"Unknown AF %u",family));
77	}
78
79	(void)printf(", length %u: ", length);
80}
81
82/*
83 * This is the top level routine of the printer.  'p' points
84 * to the ether header of the packet, 'h->ts' is the timestamp,
85 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
86 * is the number of bytes actually captured.
87 */
88u_int
89null_if_print(const struct pcap_pkthdr *h, const u_char *p)
90{
91	u_int length = h->len;
92	u_int caplen = h->caplen;
93	u_int family;
94
95	if (caplen < NULL_HDRLEN) {
96		printf("[|null]");
97		return (NULL_HDRLEN);
98	}
99
100	memcpy((char *)&family, (char *)p, sizeof(family));
101
102	/*
103	 * This isn't necessarily in our host byte order; if this is
104	 * a DLT_LOOP capture, it's in network byte order, and if
105	 * this is a DLT_NULL capture from a machine with the opposite
106	 * byte-order, it's in the opposite byte order from ours.
107	 *
108	 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
109	 */
110	if ((family & 0xFFFF0000) != 0)
111		family = SWAPLONG(family);
112
113	if (eflag)
114		null_hdr_print(family, length);
115
116	length -= NULL_HDRLEN;
117	caplen -= NULL_HDRLEN;
118	p += NULL_HDRLEN;
119
120	switch (family) {
121
122	case BSD_AFNUM_INET:
123		ip_print(gndo, p, length);
124		break;
125
126#ifdef INET6
127	case BSD_AFNUM_INET6_BSD:
128	case BSD_AFNUM_INET6_FREEBSD:
129	case BSD_AFNUM_INET6_DARWIN:
130		ip6_print(gndo, p, length);
131		break;
132#endif
133
134	case BSD_AFNUM_ISO:
135		isoclns_print(p, length, caplen);
136		break;
137
138	case BSD_AFNUM_APPLETALK:
139		atalk_print(p, length);
140		break;
141
142	case BSD_AFNUM_IPX:
143		ipx_print(p, length);
144		break;
145
146	default:
147		/* unknown AF_ value */
148		if (!eflag)
149			null_hdr_print(family, length + NULL_HDRLEN);
150		if (!suppress_default_print)
151			default_print(p, caplen);
152	}
153
154	return (NULL_HDRLEN);
155}
156
157/*
158 * Local Variables:
159 * c-style: whitesmith
160 * c-basic-offset: 8
161 * End:
162 */
163