summaryrefslogtreecommitdiff
path: root/print-sll.c
blob: 7454d334a5c12a5bb6ae80bd0fd50d7dcbf6293e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
/*
 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */
#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /tcpdump/master/tcpdump/print-sll.c,v 1.9 2002-09-05 21:25:48 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <string.h>
#include <pcap.h>

#include "interface.h"
#include "addrtoname.h"
#include "ethertype.h"

#include "ether.h"
#include "sll.h"

static inline void
sll_print(register const struct sll_header *sllp, u_int length)
{
	u_short halen;

	switch (ntohs(sllp->sll_pkttype)) {

	case LINUX_SLL_HOST:
		(void)printf("< ");
		break;

	case LINUX_SLL_BROADCAST:
		(void)printf("B ");
		break;

	case LINUX_SLL_MULTICAST:
		(void)printf("M ");
		break;

	case LINUX_SLL_OTHERHOST:
		(void)printf("P ");
		break;

	case LINUX_SLL_OUTGOING:
		(void)printf("> ");
		break;

	default:
		(void)printf("? ");
		break;
	}

	/*
	 * XXX - check the link-layer address type value?
	 * For now, we just assume 6 means Ethernet.
	 * XXX - print others as strings of hex?
	 */
	halen = ntohs(sllp->sll_halen);
	if (halen == 6)
		(void)printf("%s ", etheraddr_string(sllp->sll_addr));

	if (!qflag)
		(void)printf("%s ", etherproto_string(sllp->sll_protocol));
	(void)printf("%d: ", length);
}

/*
 * This is the top level routine of the printer.  'p' points to the
 * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 * is the number of bytes actually captured.
 */
void
sll_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
{
	u_int caplen = h->caplen;
	u_int length = h->len;
	register const struct sll_header *sllp;
	u_short pkttype;
	struct ether_header ehdr;
	u_short ether_type;
	u_short extracted_ethertype;

	++infodelay;
	ts_print(&h->ts);

	if (caplen < SLL_HDR_LEN) {
		/*
		 * XXX - this "can't happen" because "pcap-linux.c" always
		 * adds this many bytes of header to every packet in a
		 * cooked socket capture.
		 */
		printf("[|sll]");
		goto out;
	}

	sllp = (const struct sll_header *)p;

	/*
	 * Fake up an Ethernet header for the benefit of printers that
	 * insist on "packetp" pointing to an Ethernet header.
	 */
	pkttype = ntohs(sllp->sll_pkttype);

	/* The source address is in the packet header */
	memcpy(ehdr.ether_shost, sllp->sll_addr, ETHER_ADDR_LEN);

	if (pkttype != LINUX_SLL_OUTGOING) {
		/*
		 * We received this packet.
		 *
		 * We don't know the destination address, so
		 * we fake it - all 0's except that the
		 * bottommost bit of the bottommost octet
		 * is set for a unicast packet, all 0's except
		 * that the bottommost bit of the uppermost
		 * octet is set for a multicast packet, all
		 * 1's for a broadcast packet.
		 */
		if (pkttype == LINUX_SLL_BROADCAST)
			memset(ehdr.ether_dhost, 0xFF, ETHER_ADDR_LEN);
		else {
			memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
			if (pkttype == LINUX_SLL_MULTICAST)
				ehdr.ether_dhost[0] = 1;
			else
				ehdr.ether_dhost[ETHER_ADDR_LEN-1] = 1;
		}
	} else {
		/*
		 * We sent this packet; we don't know whether it's
		 * broadcast, multicast, or unicast, so just make
		 * the destination address all 0's.
		 */
		memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
	}

	if (eflag)
		sll_print(sllp, length);

	/*
	 * Some printers want to get back at the ethernet addresses,
	 * and/or check that they're not walking off the end of the packet.
	 * Rather than pass them all the way down, we set these globals.
	 */
	snapend = p + caplen;
	/*
	 * Actually, the only printers that use packetp are print-arp.c
	 * and print-bootp.c, and they assume that packetp points to an
	 * Ethernet header.  The right thing to do is to fix them to know
	 * which link type is in use when they excavate. XXX
	 */
	packetp = (u_char *)&ehdr;

	length -= SLL_HDR_LEN;
	caplen -= SLL_HDR_LEN;
	p += SLL_HDR_LEN;

	ether_type = ntohs(sllp->sll_protocol);

	/*
	 * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
	 * packet type?
	 */
	extracted_ethertype = 0;
	if (ether_type <= ETHERMTU) {
		/*
		 * Yes - what type is it?
		 */
		switch (ether_type) {

		case LINUX_SLL_P_802_3:
			/*
			 * Ethernet_802.3 IPX frame.
			 */
			ipx_print(p, length);
			break;

		case LINUX_SLL_P_802_2:
			/*
			 * 802.2.
			 * Try to print the LLC-layer header & higher layers.
			 */
			if (llc_print(p, length, caplen, ESRC(&ehdr),
			    EDST(&ehdr), &extracted_ethertype) == 0)
				goto unknown;	/* unknown LLC type */
			break;

		default:
		unknown:
			/* ether_type not known, print raw packet */
			if (!eflag)
				sll_print(sllp, length + SLL_HDR_LEN);
			if (extracted_ethertype) {
				printf("(LLC %s) ",
			       etherproto_string(htons(extracted_ethertype)));
			}
			if (!xflag && !qflag)
				default_print(p, caplen);
			break;
		}
	} else if (ether_encap_print(ether_type, p, length, caplen,
	    &extracted_ethertype) == 0) {
		/* ether_type not known, print raw packet */
		if (!eflag)
			sll_print(sllp, length + SLL_HDR_LEN);
		if (!xflag && !qflag)
			default_print(p, caplen);
	}
	if (xflag)
		default_print(p, caplen);
 out:
	putchar('\n');
	--infodelay;
	if (infoprint)
		info(0);
}