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 1.57 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
66static inline void
67null_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 */
86u_int
87null_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(gndo, 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 */
161