1/*
2 * Copyright (C) 2001 WIDE Project.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 * 3. Neither the name of the project nor the names of its contributors
13 *    may be used to endorse or promote products derived from this software
14 *    without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef lint
30static const char rcsid[] _U_ =
31    "@(#) $Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.14 2005-07-05 09:38:19 hannes Exp $ (LBL)";
32#endif
33
34#ifdef HAVE_CONFIG_H
35#include "config.h"
36#endif
37
38#include <tcpdump-stdinc.h>
39
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43
44#include "addrtoname.h"
45#include "interface.h"
46#include "extract.h"			/* must come after interface.h */
47#include "mpls.h"
48
49static const char *mpls_labelname[] = {
50/*0*/	"IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
51	"implicit NULL", "rsvd",
52/*5*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
53/*10*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
54/*15*/	"rsvd",
55};
56
57enum mpls_packet_type {
58	PT_UNKNOWN,
59	PT_IPV4,
60	PT_IPV6,
61	PT_OSI
62};
63
64/*
65 * RFC3032: MPLS label stack encoding
66 */
67void
68mpls_print(const u_char *bp, u_int length)
69{
70	const u_char *p;
71	u_int32_t label_entry;
72	u_int16_t label_stack_depth = 0;
73	enum mpls_packet_type pt = PT_UNKNOWN;
74
75	p = bp;
76	printf("MPLS");
77	do {
78		TCHECK2(*p, sizeof(label_entry));
79		label_entry = EXTRACT_32BITS(p);
80		printf("%s(label %u",
81		       (label_stack_depth && vflag) ? "\n\t" : " ",
82       		       MPLS_LABEL(label_entry));
83		label_stack_depth++;
84		if (vflag &&
85		    MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
86			printf(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
87		printf(", exp %u", MPLS_EXP(label_entry));
88		if (MPLS_STACK(label_entry))
89			printf(", [S]");
90		printf(", ttl %u)", MPLS_TTL(label_entry));
91
92		p += sizeof(label_entry);
93	} while (!MPLS_STACK(label_entry));
94
95	/*
96	 * Try to figure out the packet type.
97	 */
98	switch (MPLS_LABEL(label_entry)) {
99
100	case 0:	/* IPv4 explicit NULL label */
101	case 3:	/* IPv4 implicit NULL label */
102		pt = PT_IPV4;
103		break;
104
105	case 2:	/* IPv6 explicit NULL label */
106		pt = PT_IPV6;
107		break;
108
109	default:
110		/*
111		 * Generally there's no indication of protocol in MPLS label
112		 * encoding.
113		 *
114		 * However, draft-hsmit-isis-aal5mux-00.txt describes a
115		 * technique for encapsulating IS-IS and IP traffic on the
116		 * same ATM virtual circuit; you look at the first payload
117		 * byte to determine the network layer protocol, based on
118		 * the fact that
119		 *
120		 *	1) the first byte of an IP header is 0x45-0x4f
121		 *	   for IPv4 and 0x60-0x6f for IPv6;
122		 *
123		 *	2) the first byte of an OSI CLNP packet is 0x81,
124		 *	   the first byte of an OSI ES-IS packet is 0x82,
125		 *	   and the first byte of an OSI IS-IS packet is
126		 *	   0x83;
127		 *
128		 * so the network layer protocol can be inferred from the
129		 * first byte of the packet, if the protocol is one of the
130		 * ones listed above.
131		 *
132		 * Cisco sends control-plane traffic MPLS-encapsulated in
133		 * this fashion.
134		 */
135		switch(*p) {
136
137		case 0x45:
138		case 0x46:
139		case 0x47:
140		case 0x48:
141		case 0x49:
142		case 0x4a:
143		case 0x4b:
144		case 0x4c:
145		case 0x4d:
146		case 0x4e:
147		case 0x4f:
148			pt = PT_IPV4;
149			break;
150
151		case 0x60:
152		case 0x61:
153		case 0x62:
154		case 0x63:
155		case 0x64:
156		case 0x65:
157		case 0x66:
158		case 0x67:
159		case 0x68:
160		case 0x69:
161		case 0x6a:
162		case 0x6b:
163		case 0x6c:
164		case 0x6d:
165		case 0x6e:
166		case 0x6f:
167			pt = PT_IPV6;
168			break;
169
170		case 0x81:
171		case 0x82:
172		case 0x83:
173			pt = PT_OSI;
174			break;
175
176		default:
177			/* ok bail out - we did not figure out what it is*/
178			break;
179		}
180	}
181
182	/*
183	 * Print the payload.
184	 */
185	if (pt == PT_UNKNOWN) {
186		if (!suppress_default_print)
187			default_print(p, length - (p - bp));
188		return;
189	}
190	if (vflag)
191		printf("\n\t");
192	else
193		printf(" ");
194	switch (pt) {
195
196	case PT_IPV4:
197		ip_print(gndo, p, length - (p - bp));
198		break;
199
200	case PT_IPV6:
201#ifdef INET6
202		ip6_print(gndo, p, length - (p - bp));
203#else
204		printf("IPv6, length: %u", length);
205#endif
206		break;
207
208	case PT_OSI:
209		isoclns_print(p, length - (p - bp), length - (p - bp));
210		break;
211
212	default:
213		break;
214	}
215	return;
216
217trunc:
218	printf("[|MPLS]");
219}
220
221
222/*
223 * Local Variables:
224 * c-style: whitesmith
225 * c-basic-offset: 8
226 * End:
227 */
228