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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
30 static const char rcsid[] _U_ =
31     "@(#) $Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.13.2.1 2005/07/05 09:39:29 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 
49 static 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  */
60 void
mpls_print(const u_char * bp,u_int length)61 mpls_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 
179 trunc:
180 	printf("[|MPLS]");
181 }
182 
183 
184 /*
185  * Local Variables:
186  * c-style: whitesmith
187  * c-basic-offset: 8
188  * End:
189  */
190