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#define NETDISSECT_REWORKED
30#ifdef HAVE_CONFIG_H
31#include "config.h"
32#endif
33
34#include <tcpdump-stdinc.h>
35
36#include "interface.h"
37#include "extract.h"			/* must come after interface.h */
38#include "mpls.h"
39
40static const char *mpls_labelname[] = {
41/*0*/	"IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
42	"implicit NULL", "rsvd",
43/*5*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
44/*10*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
45/*15*/	"rsvd",
46};
47
48enum mpls_packet_type {
49	PT_UNKNOWN,
50	PT_IPV4,
51	PT_IPV6,
52	PT_OSI
53};
54
55/*
56 * RFC3032: MPLS label stack encoding
57 */
58void
59mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
60{
61	const u_char *p;
62	uint32_t label_entry;
63	uint16_t label_stack_depth = 0;
64	enum mpls_packet_type pt = PT_UNKNOWN;
65
66	p = bp;
67	ND_PRINT((ndo, "MPLS"));
68	do {
69		ND_TCHECK2(*p, sizeof(label_entry));
70		label_entry = EXTRACT_32BITS(p);
71		ND_PRINT((ndo, "%s(label %u",
72		       (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ",
73       		       MPLS_LABEL(label_entry)));
74		label_stack_depth++;
75		if (ndo->ndo_vflag &&
76		    MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
77			ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)]));
78		ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry)));
79		if (MPLS_STACK(label_entry))
80			ND_PRINT((ndo, ", [S]"));
81		ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry)));
82
83		p += sizeof(label_entry);
84	} while (!MPLS_STACK(label_entry));
85
86	/*
87	 * Try to figure out the packet type.
88	 */
89	switch (MPLS_LABEL(label_entry)) {
90
91	case 0:	/* IPv4 explicit NULL label */
92	case 3:	/* IPv4 implicit NULL label */
93		pt = PT_IPV4;
94		break;
95
96	case 2:	/* IPv6 explicit NULL label */
97		pt = PT_IPV6;
98		break;
99
100	default:
101		/*
102		 * Generally there's no indication of protocol in MPLS label
103		 * encoding.
104		 *
105		 * However, draft-hsmit-isis-aal5mux-00.txt describes a
106		 * technique for encapsulating IS-IS and IP traffic on the
107		 * same ATM virtual circuit; you look at the first payload
108		 * byte to determine the network layer protocol, based on
109		 * the fact that
110		 *
111		 *	1) the first byte of an IP header is 0x45-0x4f
112		 *	   for IPv4 and 0x60-0x6f for IPv6;
113		 *
114		 *	2) the first byte of an OSI CLNP packet is 0x81,
115		 *	   the first byte of an OSI ES-IS packet is 0x82,
116		 *	   and the first byte of an OSI IS-IS packet is
117		 *	   0x83;
118		 *
119		 * so the network layer protocol can be inferred from the
120		 * first byte of the packet, if the protocol is one of the
121		 * ones listed above.
122		 *
123		 * Cisco sends control-plane traffic MPLS-encapsulated in
124		 * this fashion.
125		 */
126		switch(*p) {
127
128		case 0x45:
129		case 0x46:
130		case 0x47:
131		case 0x48:
132		case 0x49:
133		case 0x4a:
134		case 0x4b:
135		case 0x4c:
136		case 0x4d:
137		case 0x4e:
138		case 0x4f:
139			pt = PT_IPV4;
140			break;
141
142		case 0x60:
143		case 0x61:
144		case 0x62:
145		case 0x63:
146		case 0x64:
147		case 0x65:
148		case 0x66:
149		case 0x67:
150		case 0x68:
151		case 0x69:
152		case 0x6a:
153		case 0x6b:
154		case 0x6c:
155		case 0x6d:
156		case 0x6e:
157		case 0x6f:
158			pt = PT_IPV6;
159			break;
160
161		case 0x81:
162		case 0x82:
163		case 0x83:
164			pt = PT_OSI;
165			break;
166
167		default:
168			/* ok bail out - we did not figure out what it is*/
169			break;
170		}
171	}
172
173	/*
174	 * Print the payload.
175	 */
176	if (pt == PT_UNKNOWN) {
177		if (!ndo->ndo_suppress_default_print)
178			ND_DEFAULTPRINT(p, length - (p - bp));
179		return;
180	}
181	ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " "));
182	switch (pt) {
183
184	case PT_IPV4:
185		ip_print(ndo, p, length - (p - bp));
186		break;
187
188	case PT_IPV6:
189		ip6_print(ndo, p, length - (p - bp));
190		break;
191
192	case PT_OSI:
193		isoclns_print(ndo, p, length - (p - bp), length - (p - bp));
194		break;
195
196	default:
197		break;
198	}
199	return;
200
201trunc:
202	ND_PRINT((ndo, "[|MPLS]"));
203}
204
205
206/*
207 * Local Variables:
208 * c-style: whitesmith
209 * c-basic-offset: 8
210 * End:
211 */
212