print-mpls.c revision 146773 
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 1.13 2005/04/06 21:32:41 mcr 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
57/*
58 * RFC3032: MPLS label stack encoding
59 */
60void
61mpls_print(const u_char *bp, u_int length)
62{
63	const u_char *p;
64	u_int32_t v;
65
66	p = bp;
67	printf("MPLS");
68	do {
69		TCHECK2(*p, sizeof(v));
70		v = EXTRACT_32BITS(p);
71		printf(" (");	/*)*/
72		printf("label %u", MPLS_LABEL(v));
73		if (vflag &&
74		    MPLS_LABEL(v) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
75			printf(" (%s)", mpls_labelname[MPLS_LABEL(v)]);
76		printf(", exp %u", MPLS_EXP(v));
77		if (MPLS_STACK(v))
78			printf(", [S]");
79		printf(", ttl %u", MPLS_TTL(v));
80		/*(*/
81		printf(")");
82
83		p += sizeof(v);
84	} while (!MPLS_STACK(v));
85
86	switch (MPLS_LABEL(v)) {
87	case 0:	/* IPv4 explicit NULL label */
88        case 3:	/* IPv4 implicit NULL label */
89		ip_print(gndo, p, length - (p - bp));
90		break;
91#ifdef INET6
92	case 2:	/* IPv6 explicit NULL label */
93		ip6_print(p, length - (p - bp));
94		break;
95#endif
96	default:
97		/*
98		 * Generally there's no indication of protocol in MPLS label
99		 * encoding, however draft-hsmit-isis-aal5mux-00.txt describes
100                 * a technique that looks at the first payload byte if the BOS (bottom of stack)
101                 * bit is set and tries to determine the network layer protocol
102                 * 0x45-0x4f is IPv4
103                 * 0x60-0x6f is IPv6
104                 * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
105                 * this technique is sometimes known as NULL encapsulation
106                 * and decoding is particularly useful for control-plane traffic [BGP]
107                 * which cisco by default sends MPLS encapsulated
108		 */
109
110                if (MPLS_STACK(v)) { /* only do this if the stack bit is set */
111                    switch(*p) {
112                    case 0x45:
113                    case 0x46:
114                    case 0x47:
115                    case 0x48:
116                    case 0x49:
117                    case 0x4a:
118                    case 0x4b:
119                    case 0x4c:
120                    case 0x4d:
121                    case 0x4e:
122                    case 0x4f:
123		        if (vflag>0) {
124                            printf("\n\t");
125                            ip_print(gndo, p, length - (p - bp));
126			    }
127                        else printf(", IP, length: %u",length);
128                        break;
129#ifdef INET6
130                    case 0x60:
131                    case 0x61:
132                    case 0x62:
133                    case 0x63:
134                    case 0x64:
135                    case 0x65:
136                    case 0x66:
137                    case 0x67:
138                    case 0x68:
139                    case 0x69:
140                    case 0x6a:
141                    case 0x6b:
142                    case 0x6c:
143                    case 0x6d:
144                    case 0x6e:
145                    case 0x6f:
146		        if (vflag>0) {
147                            printf("\n\t");
148                            ip6_print(p, length - (p - bp));
149                            }
150			else printf(", IPv6, length: %u",length);
151                        break;
152#endif
153                    case 0x81:
154                    case 0x82:
155                    case 0x83:
156		        if (vflag>0) {
157                            printf("\n\t");
158                            isoclns_print(p, length - (p - bp), length - (p - bp));
159			    }
160			else printf(", OSI, length: %u",length);
161                        break;
162                    default:
163                        /* ok bail out - we did not figure out what it is*/
164                        break;
165                    }
166                }
167                return;
168	}
169
170trunc:
171	printf("[|MPLS]");
172}
173
174
175/*
176 * Local Variables:
177 * c-style: whitesmith
178 * c-basic-offset: 8
179 * End:
180 */
181