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