print-null.c revision 98527 
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 98527 2002-06-21 00:49:02Z fenner $
22 */
23
24#ifndef lint
25static const char rcsid[] =
26    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.41 2001/07/05 18:54:15 guy Exp $ (LBL)";
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <sys/param.h>
34#include <sys/time.h>
35#include <sys/socket.h>
36#include <sys/file.h>
37#include <sys/ioctl.h>
38
39struct mbuf;
40struct rtentry;
41
42#include <netinet/in.h>
43
44#include <pcap.h>
45#include <stdio.h>
46#include <string.h>
47
48#include "interface.h"
49#include "addrtoname.h"
50
51#include "ip.h"
52#ifdef INET6
53#include "ip6.h"
54#endif
55
56#ifndef AF_NS
57#define AF_NS		6		/* XEROX NS protocols */
58#endif
59
60/*
61 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
62 * 32-bit integer that specifies the family, e.g. AF_INET.
63 *
64 * Note here that "host" refers to the host on which the packets were
65 * captured; that isn't necessarily *this* host.
66 *
67 * The OpenBSD DLT_LOOP packet header is the same, except that the integer
68 * is in network byte order.
69 */
70#define	NULL_HDRLEN 4
71
72static void
73null_print(u_int family, u_int length)
74{
75	if (nflag)
76		printf("AF %u ", family);
77	else {
78		switch (family) {
79
80		case AF_INET:
81			printf("ip ");
82			break;
83
84#ifdef INET6
85		case AF_INET6:
86			printf("ip6 ");
87			break;
88#endif
89
90		case AF_NS:
91			printf("ns ");
92			break;
93
94		default:
95			printf("AF %u ", family);
96			break;
97		}
98	}
99	printf("%d: ", length);
100}
101
102/*
103 * Byte-swap a 32-bit number.
104 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
105 * big-endian platforms.)
106 */
107#define	SWAPLONG(y) \
108((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
109
110void
111null_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
112{
113	u_int length = h->len;
114	u_int caplen = h->caplen;
115	const struct ip *ip;
116	u_int family;
117
118	++infodelay;
119	ts_print(&h->ts);
120
121	memcpy((char *)&family, (char *)p, sizeof(family));
122
123	/*
124	 * This isn't necessarily in our host byte order; if this is
125	 * a DLT_LOOP capture, it's in network byte order, and if
126	 * this is a DLT_NULL capture from a machine with the opposite
127	 * byte-order, it's in the opposite byte order from ours.
128	 *
129	 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
130	 */
131	if ((family & 0xFFFF0000) != 0)
132		family = SWAPLONG(family);
133
134	/*
135	 * Some printers want to get back at the link level addresses,
136	 * and/or check that they're not walking off the end of the packet.
137	 * Rather than pass them all the way down, we set these globals.
138	 */
139	packetp = p;
140	snapend = p + caplen;
141
142	length -= NULL_HDRLEN;
143
144	ip = (struct ip *)(p + NULL_HDRLEN);
145
146	if (eflag)
147		null_print(family, length);
148
149	switch (IP_V(ip)) {
150	case 4:
151		ip_print((const u_char *)ip, length);
152		break;
153#ifdef INET6
154	case 6:
155		ip6_print((const u_char *)ip, length);
156		break;
157#endif /* INET6 */
158	default:
159		printf("ip v%d", IP_V(ip));
160		break;
161	}
162
163	if (xflag)
164		default_print((const u_char *)ip, caplen - NULL_HDRLEN);
165	putchar('\n');
166	--infodelay;
167	if (infoprint)
168		info(0);
169}
170
171