1 /*
2 * Copyright (c) 1998-2007 The TCPDUMP project
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that: (1) source code
6 * distributions retain the above copyright notice and this paragraph
7 * in its entirety, and (2) distributions including binary code include
8 * the above copyright notice and this paragraph in its entirety in
9 * the documentation or other materials provided with the distribution.
10 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
11 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
12 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
13 * FOR A PARTICULAR PURPOSE.
14 *
15 * Reference documentation:
16 * http://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html
17 * http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
18 *
19 * Original code ode by Carles Kishimoto <carles.kishimoto@gmail.com>
20 */
21
22 /* \summary: Cisco VLAN Trunking Protocol (VTP) printer */
23
24 #ifdef HAVE_CONFIG_H
25 #include "config.h"
26 #endif
27
28 #include <netdissect-stdinc.h>
29
30 #include "netdissect.h"
31 #include "addrtoname.h"
32 #include "extract.h"
33
34 #define VTP_HEADER_LEN 36
35 #define VTP_DOMAIN_NAME_LEN 32
36 #define VTP_MD5_DIGEST_LEN 16
37 #define VTP_UPDATE_TIMESTAMP_LEN 12
38 #define VTP_VLAN_INFO_FIXED_PART_LEN 12 /* length of VLAN info before VLAN name */
39
40 #define VTP_SUMMARY_ADV 0x01
41 #define VTP_SUBSET_ADV 0x02
42 #define VTP_ADV_REQUEST 0x03
43 #define VTP_JOIN_MESSAGE 0x04
44
45 struct vtp_vlan_ {
46 uint8_t len;
47 uint8_t status;
48 uint8_t type;
49 uint8_t name_len;
50 uint16_t vlanid;
51 uint16_t mtu;
52 uint32_t index;
53 };
54
55 static const struct tok vtp_message_type_values[] = {
56 { VTP_SUMMARY_ADV, "Summary advertisement"},
57 { VTP_SUBSET_ADV, "Subset advertisement"},
58 { VTP_ADV_REQUEST, "Advertisement request"},
59 { VTP_JOIN_MESSAGE, "Join message"},
60 { 0, NULL }
61 };
62
63 static const struct tok vtp_header_values[] = {
64 { 0x01, "Followers"}, /* On Summary advertisement, 3rd byte is Followers */
65 { 0x02, "Seq number"}, /* On Subset advertisement, 3rd byte is Sequence number */
66 { 0x03, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
67 { 0x04, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
68 { 0, NULL }
69 };
70
71 static const struct tok vtp_vlan_type_values[] = {
72 { 0x01, "Ethernet"},
73 { 0x02, "FDDI"},
74 { 0x03, "TrCRF"},
75 { 0x04, "FDDI-net"},
76 { 0x05, "TrBRF"},
77 { 0, NULL }
78 };
79
80 static const struct tok vtp_vlan_status[] = {
81 { 0x00, "Operational"},
82 { 0x01, "Suspended"},
83 { 0, NULL }
84 };
85
86 #define VTP_VLAN_SOURCE_ROUTING_RING_NUMBER 0x01
87 #define VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER 0x02
88 #define VTP_VLAN_STP_TYPE 0x03
89 #define VTP_VLAN_PARENT_VLAN 0x04
90 #define VTP_VLAN_TRANS_BRIDGED_VLAN 0x05
91 #define VTP_VLAN_PRUNING 0x06
92 #define VTP_VLAN_BRIDGE_TYPE 0x07
93 #define VTP_VLAN_ARP_HOP_COUNT 0x08
94 #define VTP_VLAN_STE_HOP_COUNT 0x09
95 #define VTP_VLAN_BACKUP_CRF_MODE 0x0A
96
97 static const struct tok vtp_vlan_tlv_values[] = {
98 { VTP_VLAN_SOURCE_ROUTING_RING_NUMBER, "Source-Routing Ring Number TLV"},
99 { VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER, "Source-Routing Bridge Number TLV"},
100 { VTP_VLAN_STP_TYPE, "STP type TLV"},
101 { VTP_VLAN_PARENT_VLAN, "Parent VLAN TLV"},
102 { VTP_VLAN_TRANS_BRIDGED_VLAN, "Translationally bridged VLANs TLV"},
103 { VTP_VLAN_PRUNING, "Pruning TLV"},
104 { VTP_VLAN_BRIDGE_TYPE, "Bridge Type TLV"},
105 { VTP_VLAN_ARP_HOP_COUNT, "Max ARP Hop Count TLV"},
106 { VTP_VLAN_STE_HOP_COUNT, "Max STE Hop Count TLV"},
107 { VTP_VLAN_BACKUP_CRF_MODE, "Backup CRF Mode TLV"},
108 { 0, NULL }
109 };
110
111 static const struct tok vtp_stp_type_values[] = {
112 { 1, "SRT"},
113 { 2, "SRB"},
114 { 3, "Auto"},
115 { 0, NULL }
116 };
117
118 void
vtp_print(netdissect_options * ndo,const u_char * pptr,u_int length)119 vtp_print (netdissect_options *ndo,
120 const u_char *pptr, u_int length)
121 {
122 int type, len, tlv_len, tlv_value, mgmtd_len;
123 const u_char *tptr;
124 const struct vtp_vlan_ *vtp_vlan;
125
126 if (length < VTP_HEADER_LEN)
127 goto trunc;
128
129 tptr = pptr;
130
131 ND_TCHECK2(*tptr, VTP_HEADER_LEN);
132
133 type = *(tptr+1);
134 ND_PRINT((ndo, "VTPv%u, Message %s (0x%02x), length %u",
135 *tptr,
136 tok2str(vtp_message_type_values,"Unknown message type", type),
137 type,
138 length));
139
140 /* In non-verbose mode, just print version and message type */
141 if (ndo->ndo_vflag < 1) {
142 return;
143 }
144
145 /* verbose mode print all fields */
146 ND_PRINT((ndo, "\n\tDomain name: "));
147 mgmtd_len = *(tptr + 3);
148 if (mgmtd_len < 1 || mgmtd_len > 32) {
149 ND_PRINT((ndo, " [invalid MgmtD Len %d]", mgmtd_len));
150 return;
151 }
152 fn_printzp(ndo, tptr + 4, mgmtd_len, NULL);
153 ND_PRINT((ndo, ", %s: %u",
154 tok2str(vtp_header_values, "Unknown", type),
155 *(tptr+2)));
156
157 tptr += VTP_HEADER_LEN;
158
159 switch (type) {
160
161 case VTP_SUMMARY_ADV:
162
163 /*
164 * SUMMARY ADVERTISEMENT
165 *
166 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
167 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
168 * | Version | Code | Followers | MgmtD Len |
169 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
170 * | Management Domain Name (zero-padded to 32 bytes) |
171 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
172 * | Configuration revision number |
173 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
174 * | Updater Identity IP address |
175 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
176 * | Update Timestamp (12 bytes) |
177 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
178 * | MD5 digest (16 bytes) |
179 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
180 *
181 */
182
183 ND_TCHECK2(*tptr, 8);
184 ND_PRINT((ndo, "\n\t Config Rev %x, Updater %s",
185 EXTRACT_32BITS(tptr),
186 ipaddr_string(ndo, tptr+4)));
187 tptr += 8;
188 ND_TCHECK2(*tptr, VTP_UPDATE_TIMESTAMP_LEN);
189 ND_PRINT((ndo, ", Timestamp 0x%08x 0x%08x 0x%08x",
190 EXTRACT_32BITS(tptr),
191 EXTRACT_32BITS(tptr + 4),
192 EXTRACT_32BITS(tptr + 8)));
193 tptr += VTP_UPDATE_TIMESTAMP_LEN;
194 ND_TCHECK2(*tptr, VTP_MD5_DIGEST_LEN);
195 ND_PRINT((ndo, ", MD5 digest: %08x%08x%08x%08x",
196 EXTRACT_32BITS(tptr),
197 EXTRACT_32BITS(tptr + 4),
198 EXTRACT_32BITS(tptr + 8),
199 EXTRACT_32BITS(tptr + 12)));
200 tptr += VTP_MD5_DIGEST_LEN;
201 break;
202
203 case VTP_SUBSET_ADV:
204
205 /*
206 * SUBSET ADVERTISEMENT
207 *
208 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
209 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
210 * | Version | Code | Seq number | MgmtD Len |
211 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
212 * | Management Domain Name (zero-padded to 32 bytes) |
213 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
214 * | Configuration revision number |
215 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
216 * | VLAN info field 1 |
217 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
218 * | ................ |
219 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
220 * | VLAN info field N |
221 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
222 *
223 */
224
225 ND_TCHECK_32BITS(tptr);
226 ND_PRINT((ndo, ", Config Rev %x", EXTRACT_32BITS(tptr)));
227
228 /*
229 * VLAN INFORMATION
230 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
231 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
232 * | V info len | Status | VLAN type | VLAN name len |
233 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
234 * | ISL vlan id | MTU size |
235 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
236 * | 802.10 index (SAID) |
237 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
238 * | VLAN name |
239 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
240 *
241 */
242
243 tptr += 4;
244 while (tptr < (pptr+length)) {
245
246 ND_TCHECK_8BITS(tptr);
247 len = *tptr;
248 if (len == 0)
249 break;
250
251 ND_TCHECK2(*tptr, len);
252
253 vtp_vlan = (const struct vtp_vlan_*)tptr;
254 if (len < VTP_VLAN_INFO_FIXED_PART_LEN)
255 goto trunc;
256 ND_TCHECK(*vtp_vlan);
257 ND_PRINT((ndo, "\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ",
258 tok2str(vtp_vlan_status,"Unknown",vtp_vlan->status),
259 tok2str(vtp_vlan_type_values,"Unknown",vtp_vlan->type),
260 EXTRACT_16BITS(&vtp_vlan->vlanid),
261 EXTRACT_16BITS(&vtp_vlan->mtu),
262 EXTRACT_32BITS(&vtp_vlan->index)));
263 len -= VTP_VLAN_INFO_FIXED_PART_LEN;
264 tptr += VTP_VLAN_INFO_FIXED_PART_LEN;
265 if (len < 4*((vtp_vlan->name_len + 3)/4))
266 goto trunc;
267 ND_TCHECK2(*tptr, vtp_vlan->name_len);
268 fn_printzp(ndo, tptr, vtp_vlan->name_len, NULL);
269
270 /*
271 * Vlan names are aligned to 32-bit boundaries.
272 */
273 len -= 4*((vtp_vlan->name_len + 3)/4);
274 tptr += 4*((vtp_vlan->name_len + 3)/4);
275
276 /* TLV information follows */
277
278 while (len > 0) {
279
280 /*
281 * Cisco specs say 2 bytes for type + 2 bytes for length;
282 * see http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
283 * However, actual packets on the wire appear to use 1
284 * byte for the type and 1 byte for the length, so that's
285 * what we do.
286 */
287 if (len < 2)
288 goto trunc;
289 ND_TCHECK2(*tptr, 2);
290 type = *tptr;
291 tlv_len = *(tptr+1);
292
293 ND_PRINT((ndo, "\n\t\t%s (0x%04x) TLV",
294 tok2str(vtp_vlan_tlv_values, "Unknown", type),
295 type));
296
297 if (len < tlv_len * 2 + 2) {
298 ND_PRINT((ndo, " (TLV goes past the end of the packet)"));
299 return;
300 }
301 ND_TCHECK2(*tptr, tlv_len * 2 +2);
302
303 /*
304 * We assume the value is a 2-byte integer; the length is
305 * in units of 16-bit words.
306 */
307 if (tlv_len != 1) {
308 ND_PRINT((ndo, " (invalid TLV length %u != 1)", tlv_len));
309 return;
310 } else {
311 tlv_value = EXTRACT_16BITS(tptr+2);
312
313 switch (type) {
314 case VTP_VLAN_STE_HOP_COUNT:
315 ND_PRINT((ndo, ", %u", tlv_value));
316 break;
317
318 case VTP_VLAN_PRUNING:
319 ND_PRINT((ndo, ", %s (%u)",
320 tlv_value == 1 ? "Enabled" : "Disabled",
321 tlv_value));
322 break;
323
324 case VTP_VLAN_STP_TYPE:
325 ND_PRINT((ndo, ", %s (%u)",
326 tok2str(vtp_stp_type_values, "Unknown", tlv_value),
327 tlv_value));
328 break;
329
330 case VTP_VLAN_BRIDGE_TYPE:
331 ND_PRINT((ndo, ", %s (%u)",
332 tlv_value == 1 ? "SRB" : "SRT",
333 tlv_value));
334 break;
335
336 case VTP_VLAN_BACKUP_CRF_MODE:
337 ND_PRINT((ndo, ", %s (%u)",
338 tlv_value == 1 ? "Backup" : "Not backup",
339 tlv_value));
340 break;
341
342 /*
343 * FIXME those are the defined TLVs that lack a decoder
344 * you are welcome to contribute code ;-)
345 */
346
347 case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER:
348 case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER:
349 case VTP_VLAN_PARENT_VLAN:
350 case VTP_VLAN_TRANS_BRIDGED_VLAN:
351 case VTP_VLAN_ARP_HOP_COUNT:
352 default:
353 print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2);
354 break;
355 }
356 }
357 len -= 2 + tlv_len*2;
358 tptr += 2 + tlv_len*2;
359 }
360 }
361 break;
362
363 case VTP_ADV_REQUEST:
364
365 /*
366 * ADVERTISEMENT REQUEST
367 *
368 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
369 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
370 * | Version | Code | Reserved | MgmtD Len |
371 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
372 * | Management Domain Name (zero-padded to 32 bytes) |
373 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
374 * | Start value |
375 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
376 *
377 */
378
379 ND_TCHECK2(*tptr, 4);
380 ND_PRINT((ndo, "\n\tStart value: %u", EXTRACT_32BITS(tptr)));
381 break;
382
383 case VTP_JOIN_MESSAGE:
384
385 /* FIXME - Could not find message format */
386 break;
387
388 default:
389 break;
390 }
391
392 return;
393
394 trunc:
395 ND_PRINT((ndo, "[|vtp]"));
396 }
397
398 /*
399 * Local Variables:
400 * c-style: whitesmith
401 * c-basic-offset: 4
402 * End:
403 */
404