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 __RCSID("$NetBSD: print-mpls.c,v 1.5 2015/03/31 21:59:35 christos Exp $");
32 #endif
33
34 #define NETDISSECT_REWORKED
35 #ifdef HAVE_CONFIG_H
36 #include "config.h"
37 #endif
38
39 #include <tcpdump-stdinc.h>
40
41 #include "interface.h"
42 #include "extract.h" /* must come after interface.h */
43 #include "mpls.h"
44
45 static const char *mpls_labelname[] = {
46 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
47 "implicit NULL", "rsvd",
48 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
49 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
50 /*15*/ "rsvd",
51 };
52
53 enum mpls_packet_type {
54 PT_UNKNOWN,
55 PT_IPV4,
56 PT_IPV6,
57 PT_OSI
58 };
59
60 /*
61 * RFC3032: MPLS label stack encoding
62 */
63 void
mpls_print(netdissect_options * ndo,const u_char * bp,u_int length)64 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
65 {
66 const u_char *p;
67 uint32_t label_entry;
68 uint16_t label_stack_depth = 0;
69 enum mpls_packet_type pt = PT_UNKNOWN;
70
71 p = bp;
72 ND_PRINT((ndo, "MPLS"));
73 do {
74 ND_TCHECK2(*p, sizeof(label_entry));
75 label_entry = EXTRACT_32BITS(p);
76 ND_PRINT((ndo, "%s(label %u",
77 (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ",
78 MPLS_LABEL(label_entry)));
79 label_stack_depth++;
80 if (ndo->ndo_vflag &&
81 MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
82 ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)]));
83 ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry)));
84 if (MPLS_STACK(label_entry))
85 ND_PRINT((ndo, ", [S]"));
86 ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry)));
87
88 p += sizeof(label_entry);
89 } while (!MPLS_STACK(label_entry));
90
91 /*
92 * Try to figure out the packet type.
93 */
94 switch (MPLS_LABEL(label_entry)) {
95
96 case 0: /* IPv4 explicit NULL label */
97 case 3: /* IPv4 implicit NULL label */
98 pt = PT_IPV4;
99 break;
100
101 case 2: /* IPv6 explicit NULL label */
102 pt = PT_IPV6;
103 break;
104
105 default:
106 /*
107 * Generally there's no indication of protocol in MPLS label
108 * encoding.
109 *
110 * However, draft-hsmit-isis-aal5mux-00.txt describes a
111 * technique for encapsulating IS-IS and IP traffic on the
112 * same ATM virtual circuit; you look at the first payload
113 * byte to determine the network layer protocol, based on
114 * the fact that
115 *
116 * 1) the first byte of an IP header is 0x45-0x4f
117 * for IPv4 and 0x60-0x6f for IPv6;
118 *
119 * 2) the first byte of an OSI CLNP packet is 0x81,
120 * the first byte of an OSI ES-IS packet is 0x82,
121 * and the first byte of an OSI IS-IS packet is
122 * 0x83;
123 *
124 * so the network layer protocol can be inferred from the
125 * first byte of the packet, if the protocol is one of the
126 * ones listed above.
127 *
128 * Cisco sends control-plane traffic MPLS-encapsulated in
129 * this fashion.
130 */
131 switch(*p) {
132
133 case 0x45:
134 case 0x46:
135 case 0x47:
136 case 0x48:
137 case 0x49:
138 case 0x4a:
139 case 0x4b:
140 case 0x4c:
141 case 0x4d:
142 case 0x4e:
143 case 0x4f:
144 pt = PT_IPV4;
145 break;
146
147 case 0x60:
148 case 0x61:
149 case 0x62:
150 case 0x63:
151 case 0x64:
152 case 0x65:
153 case 0x66:
154 case 0x67:
155 case 0x68:
156 case 0x69:
157 case 0x6a:
158 case 0x6b:
159 case 0x6c:
160 case 0x6d:
161 case 0x6e:
162 case 0x6f:
163 pt = PT_IPV6;
164 break;
165
166 case 0x81:
167 case 0x82:
168 case 0x83:
169 pt = PT_OSI;
170 break;
171
172 default:
173 /* ok bail out - we did not figure out what it is*/
174 break;
175 }
176 }
177
178 /*
179 * Print the payload.
180 */
181 if (pt == PT_UNKNOWN) {
182 if (!ndo->ndo_suppress_default_print)
183 ND_DEFAULTPRINT(p, length - (p - bp));
184 return;
185 }
186 ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " "));
187 switch (pt) {
188
189 case PT_IPV4:
190 ip_print(ndo, p, length - (p - bp));
191 break;
192
193 case PT_IPV6:
194 ip6_print(ndo, p, length - (p - bp));
195 break;
196
197 case PT_OSI:
198 isoclns_print(ndo, p, length - (p - bp), length - (p - bp));
199 break;
200
201 default:
202 break;
203 }
204 return;
205
206 trunc:
207 ND_PRINT((ndo, "[|MPLS]"));
208 }
209
210
211 /*
212 * Local Variables:
213 * c-style: whitesmith
214 * c-basic-offset: 8
215 * End:
216 */
217