print-null.c revision 162021 
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: head/contrib/tcpdump/print-null.c 162021 2006-09-04 20:25:04Z sam $
22 */
23
24#ifndef lint
25static const char rcsid[] _U_ =
26    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.53.2.3 2005/07/07 01:24:38 guy 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
47/*
48 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
49 * 32-bit integer that specifies the family, e.g. AF_INET.
50 *
51 * Note here that "host" refers to the host on which the packets were
52 * captured; that isn't necessarily *this* host.
53 *
54 * The OpenBSD DLT_LOOP packet header is the same, except that the integer
55 * is in network byte order.
56 */
57#define	NULL_HDRLEN 4
58
59/*
60 * BSD AF_ values.
61 *
62 * Unfortunately, the BSDs don't all use the same value for AF_INET6,
63 * so, because we want to be able to read captures from all of the BSDs,
64 * we check for all of them.
65 */
66#define BSD_AF_INET		2
67#define BSD_AF_NS		6		/* XEROX NS protocols */
68#define BSD_AF_ISO		7
69#define BSD_AF_APPLETALK	16
70#define BSD_AF_IPX		23
71#define BSD_AF_INET6_BSD	24	/* OpenBSD (and probably NetBSD), BSD/OS */
72#define BSD_AF_INET6_FREEBSD	28
73#define BSD_AF_INET6_DARWIN	30
74
75const struct tok bsd_af_values[] = {
76        { BSD_AF_INET, "IPv4" },
77        { BSD_AF_NS, "NS" },
78        { BSD_AF_ISO, "ISO" },
79        { BSD_AF_APPLETALK, "Appletalk" },
80        { BSD_AF_IPX, "IPX" },
81        { BSD_AF_INET6_BSD, "IPv6" },
82        { BSD_AF_INET6_FREEBSD, "IPv6" },
83        { BSD_AF_INET6_DARWIN, "IPv6" },
84        { 0, NULL}
85};
86
87
88/*
89 * Byte-swap a 32-bit number.
90 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
91 * big-endian platforms.)
92 */
93#define	SWAPLONG(y) \
94((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
95
96static inline void
97null_hdr_print(u_int family, u_int length)
98{
99	if (!qflag) {
100		(void)printf("AF %s (%u)",
101			tok2str(bsd_af_values,"Unknown",family),family);
102	} else {
103		(void)printf("%s",
104			tok2str(bsd_af_values,"Unknown AF %u",family));
105	}
106
107	(void)printf(", length %u: ", length);
108}
109
110/*
111 * This is the top level routine of the printer.  'p' points
112 * to the ether header of the packet, 'h->ts' is the timestamp,
113 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
114 * is the number of bytes actually captured.
115 */
116u_int
117null_if_print(const struct pcap_pkthdr *h, const u_char *p)
118{
119	u_int length = h->len;
120	u_int caplen = h->caplen;
121	u_int family;
122
123	if (caplen < NULL_HDRLEN) {
124		printf("[|null]");
125		return (NULL_HDRLEN);
126	}
127
128	memcpy((char *)&family, (char *)p, sizeof(family));
129
130	/*
131	 * This isn't necessarily in our host byte order; if this is
132	 * a DLT_LOOP capture, it's in network byte order, and if
133	 * this is a DLT_NULL capture from a machine with the opposite
134	 * byte-order, it's in the opposite byte order from ours.
135	 *
136	 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
137	 */
138	if ((family & 0xFFFF0000) != 0)
139		family = SWAPLONG(family);
140
141	if (eflag)
142		null_hdr_print(family, length);
143
144	length -= NULL_HDRLEN;
145	caplen -= NULL_HDRLEN;
146	p += NULL_HDRLEN;
147
148	switch (family) {
149
150	case BSD_AF_INET:
151		ip_print(gndo, p, length);
152		break;
153
154#ifdef INET6
155	case BSD_AF_INET6_BSD:
156	case BSD_AF_INET6_FREEBSD:
157	case BSD_AF_INET6_DARWIN:
158		ip6_print(p, length);
159		break;
160#endif
161
162	case BSD_AF_ISO:
163		isoclns_print(p, length, caplen);
164		break;
165
166	case BSD_AF_APPLETALK:
167		atalk_print(p, length);
168		break;
169
170	case BSD_AF_IPX:
171		ipx_print(p, length);
172		break;
173
174	default:
175		/* unknown AF_ value */
176		if (!eflag)
177			null_hdr_print(family, length + NULL_HDRLEN);
178		if (!suppress_default_print)
179			default_print(p, caplen);
180	}
181
182	return (NULL_HDRLEN);
183}
184
185/*
186 * Local Variables:
187 * c-style: whitesmith
188 * c-basic-offset: 8
189 * End:
190 */
191