print-mpls.c revision 1.2 
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#include <sys/cdefs.h>
30#ifndef lint
31#if 0
32static const char rcsid[] _U_ =
33    "@(#) Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.14 2005-07-05 09:38:19 hannes Exp (LBL)";
34#else
35__RCSID("$NetBSD: print-mpls.c,v 1.2 2010/12/05 05:11:30 christos Exp $");
36#endif
37#endif
38
39#ifdef HAVE_CONFIG_H
40#include "config.h"
41#endif
42
43#include <tcpdump-stdinc.h>
44
45#include <stdio.h>
46#include <stdlib.h>
47#include <string.h>
48
49#include "addrtoname.h"
50#include "interface.h"
51#include "extract.h"			/* must come after interface.h */
52#include "mpls.h"
53
54static const char *mpls_labelname[] = {
55/*0*/	"IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
56	"implicit NULL", "rsvd",
57/*5*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
58/*10*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
59/*15*/	"rsvd",
60};
61
62/*
63 * RFC3032: MPLS label stack encoding
64 */
65void
66mpls_print(const u_char *bp, u_int length)
67{
68	const u_char *p;
69	u_int32_t label_entry;
70        u_int16_t label_stack_depth = 0;
71
72	p = bp;
73	printf("MPLS");
74	do {
75		TCHECK2(*p, sizeof(label_entry));
76		label_entry = EXTRACT_32BITS(p);
77		printf("%s(label %u",
78                       label_stack_depth ? "\n\t" : " ",
79                       MPLS_LABEL(label_entry));
80                label_stack_depth++;
81		if (vflag &&
82		    MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
83			printf(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
84		printf(", exp %u", MPLS_EXP(label_entry));
85		if (MPLS_STACK(label_entry))
86			printf(", [S]");
87		printf(", ttl %u)", MPLS_TTL(label_entry));
88
89		p += sizeof(label_entry);
90	} while (!MPLS_STACK(label_entry));
91
92	switch (MPLS_LABEL(label_entry)) {
93	case 0:	/* IPv4 explicit NULL label */
94        case 3:	/* IPv4 implicit NULL label */
95                if (vflag>0) {
96                        printf("\n\t");
97                        ip_print(gndo, p, length - (p - bp));
98                }
99                else printf(", IP, length: %u",length);
100		break;
101#ifdef INET6
102	case 2:	/* IPv6 explicit NULL label */
103                if (vflag>0) {
104                        printf("\n\t");
105                        ip6_print(p, length - (p - bp));
106                }
107                else printf(", IPv6, length: %u",length);
108		break;
109#endif
110	default:
111		/*
112		 * Generally there's no indication of protocol in MPLS label
113		 * encoding, however draft-hsmit-isis-aal5mux-00.txt describes
114                 * a technique that looks at the first payload byte if the BOS (bottom of stack)
115                 * bit is set and tries to determine the network layer protocol
116                 * 0x45-0x4f is IPv4
117                 * 0x60-0x6f is IPv6
118                 * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
119                 * this technique is sometimes known as NULL encapsulation
120                 * and decoding is particularly useful for control-plane traffic [BGP]
121                 * which cisco by default sends MPLS encapsulated
122		 */
123
124                if (MPLS_STACK(label_entry)) { /* only do this if the stack bit is set */
125                    switch(*p) {
126                    case 0x45:
127                    case 0x46:
128                    case 0x47:
129                    case 0x48:
130                    case 0x49:
131                    case 0x4a:
132                    case 0x4b:
133                    case 0x4c:
134                    case 0x4d:
135                    case 0x4e:
136                    case 0x4f:
137		        if (vflag>0) {
138                            printf("\n\t");
139                            ip_print(gndo, p, length - (p - bp));
140			    }
141                        else printf(", IP, length: %u",length);
142                        break;
143#ifdef INET6
144                    case 0x60:
145                    case 0x61:
146                    case 0x62:
147                    case 0x63:
148                    case 0x64:
149                    case 0x65:
150                    case 0x66:
151                    case 0x67:
152                    case 0x68:
153                    case 0x69:
154                    case 0x6a:
155                    case 0x6b:
156                    case 0x6c:
157                    case 0x6d:
158                    case 0x6e:
159                    case 0x6f:
160		        if (vflag>0) {
161                            printf("\n\t");
162                            ip6_print(p, length - (p - bp));
163                            }
164			else printf(", IPv6, length: %u",length);
165                        break;
166#endif
167                    case 0x81:
168                    case 0x82:
169                    case 0x83:
170		        if (vflag>0) {
171                            printf("\n\t");
172                            isoclns_print(p, length - (p - bp), length - (p - bp));
173			    }
174			else printf(", OSI, length: %u",length);
175                        break;
176                    default:
177                        /* ok bail out - we did not figure out what it is*/
178                        break;
179                    }
180                }
181                return;
182	}
183
184trunc:
185	printf("[|MPLS]");
186}
187
188
189/*
190 * Local Variables:
191 * c-style: whitesmith
192 * c-basic-offset: 8
193 * End:
194 */
195