print-mpls.c revision 127668 
1272343Sngie/*
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 1.8.2.2 2003/11/16 08:51:34 guy 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
48#define LABEL_MASK	0xfffff000
49#define LABEL_SHIFT	12
50#define	EXP_MASK	0x00000e00
51#define EXP_SHIFT	9
52#define	STACK_MASK	0x00000100
53#define STACK_SHIFT	8
54#define TTL_MASK	0x000000ff
55#define TTL_SHIFT	0
56
57#define MPLS_LABEL(x)	(((x) & LABEL_MASK) >> LABEL_SHIFT)
58#define MPLS_EXP(x)	(((x) & EXP_MASK) >> EXP_SHIFT)
59#define MPLS_STACK(x)	(((x) & STACK_MASK) >> STACK_SHIFT)
60#define MPLS_TTL(x)	(((x) & TTL_MASK) >> TTL_SHIFT)
61
62static const char *mpls_labelname[] = {
63/*0*/	"IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
64	"implicit NULL", "rsvd",
65/*5*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
66/*10*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
67/*15*/	"rsvd",
68};
69
70/*
71 * RFC3032: MPLS label stack encoding
72 */
73void
74mpls_print(const u_char *bp, u_int length)
75{
76	const u_char *p;
77	u_int32_t v;
78
79	p = bp;
80	printf("MPLS");
81	do {
82		TCHECK2(*p, sizeof(v));
83		v = EXTRACT_32BITS(p);
84		printf(" (");	/*)*/
85		printf("label %u", MPLS_LABEL(v));
86		if (vflag &&
87		    MPLS_LABEL(v) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
88			printf(" (%s)", mpls_labelname[MPLS_LABEL(v)]);
89		printf(", exp %u", MPLS_EXP(v));
90		if (MPLS_STACK(v))
91			printf(", [S]");
92		printf(", ttl %u", MPLS_TTL(v));
93		/*(*/
94		printf(")");
95
96		p += sizeof(v);
97	} while (!MPLS_STACK(v));
98
99	switch (MPLS_LABEL(v)) {
100	case 0:	/* IPv4 explicit NULL label */
101        case 3:	/* IPv4 implicit NULL label */
102		ip_print(p, length - (p - bp));
103		break;
104#ifdef INET6
105	case 2:	/* IPv6 explicit NULL label */
106		ip6_print(p, length - (p - bp));
107		break;
108#endif
109	default:
110		/*
111		 * Generally there's no indication of protocol in MPLS label
112		 * encoding, however draft-hsmit-isis-aal5mux-00.txt describes
113                 * a technique that looks at the first payload byte if the BOS (bottom of stack)
114                 * bit is set and tries to determine the network layer protocol
115                 * 0x45-0x4f is IPv4
116                 * 0x60-0x6f is IPv6
117                 * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
118                 * this technique is sometimes known as NULL encapsulation
119                 * and decoding is particularly useful for control-plane traffic [BGP]
120                 * which cisco by default sends MPLS encapsulated
121		 */
122
123                if (MPLS_STACK(v)) { /* only do this if the stack bit is set */
124                    switch(*p) {
125                    case 0x45:
126                    case 0x46:
127                    case 0x47:
128                    case 0x48:
129                    case 0x49:
130                    case 0x4a:
131                    case 0x4b:
132                    case 0x4c:
133                    case 0x4d:
134                    case 0x4e:
135                    case 0x4f:
136		        if (vflag>0) {
137                            printf("\n\t");
138                            ip_print(p, length - (p - bp));
139			    }
140                        else printf(", IP, length: %u",length);
141                        break;
142#ifdef INET6
143                    case 0x60:
144                    case 0x61:
145                    case 0x62:
146                    case 0x63:
147                    case 0x64:
148                    case 0x65:
149                    case 0x66:
150                    case 0x67:
151                    case 0x68:
152                    case 0x69:
153                    case 0x6a:
154                    case 0x6b:
155                    case 0x6c:
156                    case 0x6d:
157                    case 0x6e:
158                    case 0x6f:
159		        if (vflag>0) {
160                            printf("\n\t");
161                            ip6_print(p, length - (p - bp));
162                            }
163			else printf(", IPv6, length: %u",length);
164                        break;
165#endif
166                    case 0x81:
167                    case 0x82:
168                    case 0x83:
169		        if (vflag>0) {
170                            printf("\n\t");
171                            isoclns_print(p, length - (p - bp), length - (p - bp));
172			    }
173			else printf(", OSI, length: %u",length);
174                        break;
175                    default:
176                        /* ok bail out - we did not figure out what it is*/
177                        break;
178                    }
179                }
180                return;
181	}
182
183trunc:
184	printf("[|MPLS]");
185}
186
187/*
188 * draft-ietf-mpls-lsp-ping-02.txt
189 */
190void
191mpls_lsp_ping_print(const u_char *pptr, u_int length)
192{
193    printf("UDP, LSP-PING, length: %u", length);
194    if (vflag >1)
195	print_unknown_data(pptr,"\n\t  ", length);
196}
197