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 /* \summary: Multi-Protocol Label Switching (MPLS) printer */
30
31 #ifdef HAVE_CONFIG_H
32 #include "config.h"
33 #endif
34
35 #include <netdissect-stdinc.h>
36
37 #include "netdissect.h"
38 #include "extract.h"
39 #include "mpls.h"
40
41 static const char *mpls_labelname[] = {
42 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
43 "implicit NULL", "rsvd",
44 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
45 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
46 /*15*/ "rsvd",
47 };
48
49 enum mpls_packet_type {
50 PT_UNKNOWN,
51 PT_IPV4,
52 PT_IPV6,
53 PT_OSI
54 };
55
56 /*
57 * RFC3032: MPLS label stack encoding
58 */
59 void
mpls_print(netdissect_options * ndo,const u_char * bp,u_int length)60 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
61 {
62 const u_char *p;
63 uint32_t label_entry;
64 uint16_t label_stack_depth = 0;
65 enum mpls_packet_type pt = PT_UNKNOWN;
66
67 p = bp;
68 ND_PRINT((ndo, "MPLS"));
69 do {
70 ND_TCHECK2(*p, sizeof(label_entry));
71 if (length < sizeof(label_entry)) {
72 ND_PRINT((ndo, "[|MPLS], length %u", length));
73 return;
74 }
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 length -= sizeof(label_entry);
90 } while (!MPLS_STACK(label_entry));
91
92 /*
93 * Try to figure out the packet type.
94 */
95 switch (MPLS_LABEL(label_entry)) {
96
97 case 0: /* IPv4 explicit NULL label */
98 case 3: /* IPv4 implicit NULL label */
99 pt = PT_IPV4;
100 break;
101
102 case 2: /* IPv6 explicit NULL label */
103 pt = PT_IPV6;
104 break;
105
106 default:
107 /*
108 * Generally there's no indication of protocol in MPLS label
109 * encoding.
110 *
111 * However, draft-hsmit-isis-aal5mux-00.txt describes a
112 * technique for encapsulating IS-IS and IP traffic on the
113 * same ATM virtual circuit; you look at the first payload
114 * byte to determine the network layer protocol, based on
115 * the fact that
116 *
117 * 1) the first byte of an IP header is 0x45-0x4f
118 * for IPv4 and 0x60-0x6f for IPv6;
119 *
120 * 2) the first byte of an OSI CLNP packet is 0x81,
121 * the first byte of an OSI ES-IS packet is 0x82,
122 * and the first byte of an OSI IS-IS packet is
123 * 0x83;
124 *
125 * so the network layer protocol can be inferred from the
126 * first byte of the packet, if the protocol is one of the
127 * ones listed above.
128 *
129 * Cisco sends control-plane traffic MPLS-encapsulated in
130 * this fashion.
131 */
132 ND_TCHECK(*p);
133 if (length < 1) {
134 /* nothing to print */
135 return;
136 }
137 switch(*p) {
138
139 case 0x45:
140 case 0x46:
141 case 0x47:
142 case 0x48:
143 case 0x49:
144 case 0x4a:
145 case 0x4b:
146 case 0x4c:
147 case 0x4d:
148 case 0x4e:
149 case 0x4f:
150 pt = PT_IPV4;
151 break;
152
153 case 0x60:
154 case 0x61:
155 case 0x62:
156 case 0x63:
157 case 0x64:
158 case 0x65:
159 case 0x66:
160 case 0x67:
161 case 0x68:
162 case 0x69:
163 case 0x6a:
164 case 0x6b:
165 case 0x6c:
166 case 0x6d:
167 case 0x6e:
168 case 0x6f:
169 pt = PT_IPV6;
170 break;
171
172 case 0x81:
173 case 0x82:
174 case 0x83:
175 pt = PT_OSI;
176 break;
177
178 default:
179 /* ok bail out - we did not figure out what it is*/
180 break;
181 }
182 }
183
184 /*
185 * Print the payload.
186 */
187 if (pt == PT_UNKNOWN) {
188 if (!ndo->ndo_suppress_default_print)
189 ND_DEFAULTPRINT(p, length);
190 return;
191 }
192 ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " "));
193 switch (pt) {
194
195 case PT_IPV4:
196 ip_print(ndo, p, length);
197 break;
198
199 case PT_IPV6:
200 ip6_print(ndo, p, length);
201 break;
202
203 case PT_OSI:
204 isoclns_print(ndo, p, length, length);
205 break;
206
207 default:
208 break;
209 }
210 return;
211
212 trunc:
213 ND_PRINT((ndo, "[|MPLS]"));
214 }
215
216
217 /*
218 * Local Variables:
219 * c-style: whitesmith
220 * c-basic-offset: 8
221 * End:
222 */
223