print-mpls.c revision 190207 
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
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 label_entry;
65        u_int16_t label_stack_depth = 0;
66
67	p = bp;
68	printf("MPLS");
69	do {
70		TCHECK2(*p, sizeof(label_entry));
71		label_entry = EXTRACT_32BITS(p);
72		printf("%s(label %u",
73                       label_stack_depth ? "\n\t" : " ",
74                       MPLS_LABEL(label_entry));
75                label_stack_depth++;
76		if (vflag &&
77		    MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
78			printf(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
79		printf(", exp %u", MPLS_EXP(label_entry));
80		if (MPLS_STACK(label_entry))
81			printf(", [S]");
82		printf(", ttl %u)", MPLS_TTL(label_entry));
83
84		p += sizeof(label_entry);
85	} while (!MPLS_STACK(label_entry));
86
87	switch (MPLS_LABEL(label_entry)) {
88	case 0:	/* IPv4 explicit NULL label */
89        case 3:	/* IPv4 implicit NULL label */
90                if (vflag>0) {
91                        printf("\n\t");
92                        ip_print(gndo, p, length - (p - bp));
93                }
94                else printf(", IP, length: %u",length);
95		break;
96#ifdef INET6
97	case 2:	/* IPv6 explicit NULL label */
98                if (vflag>0) {
99                        printf("\n\t");
100                        ip6_print(p, length - (p - bp));
101                }
102                else printf(", IPv6, length: %u",length);
103		break;
104#endif
105	default:
106		/*
107		 * Generally there's no indication of protocol in MPLS label
108		 * encoding, however draft-hsmit-isis-aal5mux-00.txt describes
109                 * a technique that looks at the first payload byte if the BOS (bottom of stack)
110                 * bit is set and tries to determine the network layer protocol
111                 * 0x45-0x4f is IPv4
112                 * 0x60-0x6f is IPv6
113                 * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
114                 * this technique is sometimes known as NULL encapsulation
115                 * and decoding is particularly useful for control-plane traffic [BGP]
116                 * which cisco by default sends MPLS encapsulated
117		 */
118
119                if (MPLS_STACK(label_entry)) { /* only do this if the stack bit is set */
120                    switch(*p) {
121                    case 0x45:
122                    case 0x46:
123                    case 0x47:
124                    case 0x48:
125                    case 0x49:
126                    case 0x4a:
127                    case 0x4b:
128                    case 0x4c:
129                    case 0x4d:
130                    case 0x4e:
131                    case 0x4f:
132		        if (vflag>0) {
133                            printf("\n\t");
134                            ip_print(gndo, p, length - (p - bp));
135			    }
136                        else printf(", IP, length: %u",length);
137                        break;
138#ifdef INET6
139                    case 0x60:
140                    case 0x61:
141                    case 0x62:
142                    case 0x63:
143                    case 0x64:
144                    case 0x65:
145                    case 0x66:
146                    case 0x67:
147                    case 0x68:
148                    case 0x69:
149                    case 0x6a:
150                    case 0x6b:
151                    case 0x6c:
152                    case 0x6d:
153                    case 0x6e:
154                    case 0x6f:
155		        if (vflag>0) {
156                            printf("\n\t");
157                            ip6_print(p, length - (p - bp));
158                            }
159			else printf(", IPv6, length: %u",length);
160                        break;
161#endif
162                    case 0x81:
163                    case 0x82:
164                    case 0x83:
165		        if (vflag>0) {
166                            printf("\n\t");
167                            isoclns_print(p, length - (p - bp), length - (p - bp));
168			    }
169			else printf(", OSI, length: %u",length);
170                        break;
171                    default:
172                        /* ok bail out - we did not figure out what it is*/
173                        break;
174                    }
175                }
176                return;
177	}
178
179trunc:
180	printf("[|MPLS]");
181}
182
183
184/*
185 * Local Variables:
186 * c-style: whitesmith
187 * c-basic-offset: 8
188 * End:
189 */
190