print-mpls.c revision 111726 
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[] =
31    "@(#) $Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.2.4.1 2002/05/07 18:36:28 fenner Exp $ (LBL)";
32#endif
33
34#ifdef HAVE_CONFIG_H
35#include "config.h"
36#endif
37
38#include <sys/param.h>
39#include <sys/time.h>
40#include <sys/socket.h>
41
42#include <netinet/in.h>
43
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47#include <unistd.h>
48
49#include "addrtoname.h"
50#include "interface.h"
51#include "extract.h"			/* must come after interface.h */
52
53#define LABEL_MASK	0xfffff000
54#define LABEL_SHIFT	12
55#define	EXP_MASK	0x00000e00
56#define EXP_SHIFT	9
57#define	STACK_MASK	0x00000100
58#define STACK_SHIFT	8
59#define TTL_MASK	0x000000ff
60#define TTL_SHIFT	0
61
62#define MPLS_LABEL(x)	(((x) & LABEL_MASK) >> LABEL_SHIFT)
63#define MPLS_EXP(x)	(((x) & EXP_MASK) >> EXP_SHIFT)
64#define MPLS_STACK(x)	(((x) & STACK_MASK) >> STACK_SHIFT)
65#define MPLS_TTL(x)	(((x) & TTL_MASK) >> TTL_SHIFT)
66
67static const char *mpls_labelname[] = {
68/*0*/	"IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
69	"implicit NULL", "rsvd",
70/*5*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
71/*10*/	"rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
72/*15*/	"rsvd",
73};
74
75/*
76 * RFC3032: MPLS label stack encoding
77 */
78void
79mpls_print(const u_char *bp, u_int length)
80{
81	const u_char *p;
82	u_int32_t v;
83
84	p = bp;
85	printf("MPLS");
86	do {
87		TCHECK2(*p, sizeof(v));
88		v = EXTRACT_32BITS(p);
89		printf(" (");	/*)*/
90		printf("label 0x%x", MPLS_LABEL(v));
91		if (vflag &&
92		    MPLS_LABEL(v) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
93			printf("(%s)", mpls_labelname[MPLS_LABEL(v)]);
94		if (MPLS_EXP(v))
95			printf(" exp 0x%x", MPLS_EXP(v));
96		if (MPLS_STACK(v))
97			printf("[S]");
98		printf(" TTL %u", MPLS_TTL(v));
99		/*(*/
100		printf(")");
101
102		p += sizeof(v);
103	} while (!MPLS_STACK(v));
104
105	switch (MPLS_LABEL(v)) {
106	case 0:	/* IPv4 explicit NULL label */
107		ip_print(p, length - (p - bp));
108		break;
109#ifdef INET6
110	case 2:	/* IPv6 explicit NULL label */
111		ip6_print(p, length - (p - bp));
112		break;
113#endif
114	default:
115		/*
116		 * Since there's no indication of protocol in MPLS label
117		 * encoding, we can print nothing further.
118		 */
119		return;
120	}
121
122trunc:
123	printf("[|MPLS]");
124}
125