print-null.c revision 146778 
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 146778 2005-05-29 19:09:28Z sam $
22 */
23
24#ifndef lint
25static const char rcsid[] _U_ =
26    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.53 2005/04/06 21:32:41 mcr 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
75static void
76null_print(u_int family, u_int length)
77{
78	if (nflag)
79		printf("AF %u ", family);
80	else {
81		switch (family) {
82
83		case BSD_AF_INET:
84			printf("ip ");
85			break;
86
87#ifdef INET6
88		case BSD_AF_INET6_BSD:
89		case BSD_AF_INET6_FREEBSD:
90		case BSD_AF_INET6_DARWIN:
91			printf("ip6 ");
92			break;
93#endif
94
95		case BSD_AF_NS:
96			printf("ns ");
97			break;
98
99		case BSD_AF_ISO:
100			printf("osi ");
101			break;
102
103		case BSD_AF_APPLETALK:
104			printf("atalk ");
105			break;
106
107		case BSD_AF_IPX:
108			printf("ipx ");
109			break;
110
111		default:
112			printf("AF %u ", family);
113			break;
114		}
115	}
116	printf("%d: ", length);
117}
118
119/*
120 * Byte-swap a 32-bit number.
121 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
122 * big-endian platforms.)
123 */
124#define	SWAPLONG(y) \
125((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
126
127/*
128 * This is the top level routine of the printer.  'p' points
129 * to the ether header of the packet, 'h->ts' is the timestamp,
130 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
131 * is the number of bytes actually captured.
132 */
133u_int
134null_if_print(const struct pcap_pkthdr *h, const u_char *p)
135{
136	u_int length = h->len;
137	u_int caplen = h->caplen;
138	u_int family;
139
140	if (caplen < NULL_HDRLEN) {
141		printf("[|null]");
142		return (NULL_HDRLEN);
143	}
144
145	memcpy((char *)&family, (char *)p, sizeof(family));
146
147	/*
148	 * This isn't necessarily in our host byte order; if this is
149	 * a DLT_LOOP capture, it's in network byte order, and if
150	 * this is a DLT_NULL capture from a machine with the opposite
151	 * byte-order, it's in the opposite byte order from ours.
152	 *
153	 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
154	 */
155	if ((family & 0xFFFF0000) != 0)
156		family = SWAPLONG(family);
157
158	length -= NULL_HDRLEN;
159	caplen -= NULL_HDRLEN;
160	p += NULL_HDRLEN;
161
162	if (eflag)
163		null_print(family, length);
164
165	switch (family) {
166
167	case BSD_AF_INET:
168	        ip_print(gndo, p, length);
169		break;
170
171#ifdef INET6
172	case BSD_AF_INET6_BSD:
173	case BSD_AF_INET6_FREEBSD:
174	case BSD_AF_INET6_DARWIN:
175		ip6_print(p, length);
176		break;
177#endif
178
179	case BSD_AF_ISO:
180		isoclns_print(p, length, caplen);
181		break;
182
183	case BSD_AF_APPLETALK:
184		atalk_print(p, length);
185		break;
186
187	case BSD_AF_IPX:
188		ipx_print(p, length);
189		break;
190
191	default:
192		/* unknown AF_ value */
193		if (!eflag)
194			null_print(family, length + NULL_HDRLEN);
195		if (!xflag && !qflag)
196			default_print(p, caplen);
197	}
198
199	return (NULL_HDRLEN);
200}
201
202/*
203 * Local Variables:
204 * c-style: whitesmith
205 * c-basic-offset: 8
206 * End:
207 */
208