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 * https://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html
17 * https://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 #define ND_LONGJMP_FROM_TCHECK
31 #include "netdissect.h"
32 #include "addrtoname.h"
33 #include "extract.h"
34
35 #define VTP_HEADER_LEN 36
36 #define VTP_DOMAIN_NAME_LEN 32
37 #define VTP_MD5_DIGEST_LEN 16
38 #define VTP_UPDATE_TIMESTAMP_LEN 12
39 #define VTP_VLAN_INFO_FIXED_PART_LEN 12 /* length of VLAN info before VLAN name */
40
41 #define VTP_SUMMARY_ADV 0x01
42 #define VTP_SUBSET_ADV 0x02
43 #define VTP_ADV_REQUEST 0x03
44 #define VTP_JOIN_MESSAGE 0x04
45
46 struct vtp_vlan_ {
47 nd_uint8_t len;
48 nd_uint8_t status;
49 nd_uint8_t type;
50 nd_uint8_t name_len;
51 nd_uint16_t vlanid;
52 nd_uint16_t mtu;
53 nd_uint32_t index;
54 };
55
56 static const struct tok vtp_message_type_values[] = {
57 { VTP_SUMMARY_ADV, "Summary advertisement"},
58 { VTP_SUBSET_ADV, "Subset advertisement"},
59 { VTP_ADV_REQUEST, "Advertisement request"},
60 { VTP_JOIN_MESSAGE, "Join message"},
61 { 0, NULL }
62 };
63
64 static const struct tok vtp_header_values[] = {
65 { 0x01, "Followers"}, /* On Summary advertisement, 3rd byte is Followers */
66 { 0x02, "Seq number"}, /* On Subset advertisement, 3rd byte is Sequence number */
67 { 0x03, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
68 { 0x04, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
69 { 0, NULL }
70 };
71
72 static const struct tok vtp_vlan_type_values[] = {
73 { 0x01, "Ethernet"},
74 { 0x02, "FDDI"},
75 { 0x03, "TrCRF"},
76 { 0x04, "FDDI-net"},
77 { 0x05, "TrBRF"},
78 { 0, NULL }
79 };
80
81 static const struct tok vtp_vlan_status[] = {
82 { 0x00, "Operational"},
83 { 0x01, "Suspended"},
84 { 0, NULL }
85 };
86
87 #define VTP_VLAN_SOURCE_ROUTING_RING_NUMBER 0x01
88 #define VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER 0x02
89 #define VTP_VLAN_STP_TYPE 0x03
90 #define VTP_VLAN_PARENT_VLAN 0x04
91 #define VTP_VLAN_TRANS_BRIDGED_VLAN 0x05
92 #define VTP_VLAN_PRUNING 0x06
93 #define VTP_VLAN_BRIDGE_TYPE 0x07
94 #define VTP_VLAN_ARP_HOP_COUNT 0x08
95 #define VTP_VLAN_STE_HOP_COUNT 0x09
96 #define VTP_VLAN_BACKUP_CRF_MODE 0x0A
97
98 static const struct tok vtp_vlan_tlv_values[] = {
99 { VTP_VLAN_SOURCE_ROUTING_RING_NUMBER, "Source-Routing Ring Number TLV"},
100 { VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER, "Source-Routing Bridge Number TLV"},
101 { VTP_VLAN_STP_TYPE, "STP type TLV"},
102 { VTP_VLAN_PARENT_VLAN, "Parent VLAN TLV"},
103 { VTP_VLAN_TRANS_BRIDGED_VLAN, "Translationally bridged VLANs TLV"},
104 { VTP_VLAN_PRUNING, "Pruning TLV"},
105 { VTP_VLAN_BRIDGE_TYPE, "Bridge Type TLV"},
106 { VTP_VLAN_ARP_HOP_COUNT, "Max ARP Hop Count TLV"},
107 { VTP_VLAN_STE_HOP_COUNT, "Max STE Hop Count TLV"},
108 { VTP_VLAN_BACKUP_CRF_MODE, "Backup CRF Mode TLV"},
109 { 0, NULL }
110 };
111
112 static const struct tok vtp_stp_type_values[] = {
113 { 1, "SRT"},
114 { 2, "SRB"},
115 { 3, "Auto"},
116 { 0, NULL }
117 };
118
119 void
vtp_print(netdissect_options * ndo,const u_char * pptr,const u_int length)120 vtp_print(netdissect_options *ndo,
121 const u_char *pptr, const u_int length)
122 {
123 u_int type, len, name_len, tlv_len, tlv_value, mgmtd_len;
124 const u_char *tptr;
125 const struct vtp_vlan_ *vtp_vlan;
126
127 ndo->ndo_protocol = "vtp";
128 if (length < VTP_HEADER_LEN)
129 goto invalid;
130
131 tptr = pptr;
132
133 ND_TCHECK_LEN(tptr, VTP_HEADER_LEN);
134
135 type = GET_U_1(tptr + 1);
136 ND_PRINT("VTPv%u, Message %s (0x%02x), length %u",
137 GET_U_1(tptr),
138 tok2str(vtp_message_type_values,"Unknown message type", type),
139 type,
140 length);
141
142 /* In non-verbose mode, just print version and message type */
143 if (ndo->ndo_vflag < 1) {
144 goto tcheck_full_packet;
145 }
146
147 /* verbose mode print all fields */
148 ND_PRINT("\n\tDomain name: ");
149 mgmtd_len = GET_U_1(tptr + 3);
150 if (mgmtd_len < 1 || mgmtd_len > VTP_DOMAIN_NAME_LEN) {
151 ND_PRINT(" [invalid MgmtD Len %u]", mgmtd_len);
152 goto invalid;
153 }
154 nd_printjnp(ndo, tptr + 4, mgmtd_len);
155 ND_PRINT(", %s: %u",
156 tok2str(vtp_header_values, "Unknown", type),
157 GET_U_1(tptr + 2));
158
159 tptr += VTP_HEADER_LEN;
160
161 switch (type) {
162
163 case VTP_SUMMARY_ADV:
164
165 /*
166 * SUMMARY ADVERTISEMENT
167 *
168 * 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
169 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
170 * | Version | Code | Followers | MgmtD Len |
171 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
172 * | Management Domain Name (zero-padded to 32 bytes) |
173 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
174 * | Configuration revision number |
175 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
176 * | Updater Identity IP address |
177 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
178 * | Update Timestamp (12 bytes) |
179 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
180 * | MD5 digest (16 bytes) |
181 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
182 *
183 */
184
185 ND_PRINT("\n\t Config Rev %x, Updater %s",
186 GET_BE_U_4(tptr),
187 GET_IPADDR_STRING(tptr+4));
188 tptr += 8;
189 ND_PRINT(", Timestamp 0x%08x 0x%08x 0x%08x",
190 GET_BE_U_4(tptr),
191 GET_BE_U_4(tptr + 4),
192 GET_BE_U_4(tptr + 8));
193 tptr += VTP_UPDATE_TIMESTAMP_LEN;
194 ND_PRINT(", MD5 digest: %08x%08x%08x%08x",
195 GET_BE_U_4(tptr),
196 GET_BE_U_4(tptr + 4),
197 GET_BE_U_4(tptr + 8),
198 GET_BE_U_4(tptr + 12));
199 tptr += VTP_MD5_DIGEST_LEN;
200 break;
201
202 case VTP_SUBSET_ADV:
203
204 /*
205 * SUBSET ADVERTISEMENT
206 *
207 * 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
208 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
209 * | Version | Code | Seq number | MgmtD Len |
210 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
211 * | Management Domain Name (zero-padded to 32 bytes) |
212 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
213 * | Configuration revision number |
214 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
215 * | VLAN info field 1 |
216 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
217 * | ................ |
218 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
219 * | VLAN info field N |
220 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
221 *
222 */
223
224 ND_PRINT(", Config Rev %x", GET_BE_U_4(tptr));
225
226 /*
227 * VLAN INFORMATION
228 * 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
229 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
230 * | V info len | Status | VLAN type | VLAN name len |
231 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
232 * | ISL vlan id | MTU size |
233 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
234 * | 802.10 index (SAID) |
235 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
236 * | VLAN name |
237 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
238 *
239 */
240
241 tptr += 4;
242 while ((unsigned)(tptr - pptr) < length) {
243
244 len = GET_U_1(tptr);
245 if (len == 0)
246 break;
247
248 ND_TCHECK_LEN(tptr, len);
249
250 vtp_vlan = (const struct vtp_vlan_*)tptr;
251 if (len < VTP_VLAN_INFO_FIXED_PART_LEN)
252 goto invalid;
253 ND_PRINT("\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ",
254 tok2str(vtp_vlan_status,"Unknown",GET_U_1(vtp_vlan->status)),
255 tok2str(vtp_vlan_type_values,"Unknown",GET_U_1(vtp_vlan->type)),
256 GET_BE_U_2(vtp_vlan->vlanid),
257 GET_BE_U_2(vtp_vlan->mtu),
258 GET_BE_U_4(vtp_vlan->index));
259 len -= VTP_VLAN_INFO_FIXED_PART_LEN;
260 tptr += VTP_VLAN_INFO_FIXED_PART_LEN;
261 name_len = GET_U_1(vtp_vlan->name_len);
262 if (len < 4*((name_len + 3)/4))
263 goto invalid;
264 nd_printjnp(ndo, tptr, name_len);
265
266 /*
267 * Vlan names are aligned to 32-bit boundaries.
268 */
269 len -= 4*((name_len + 3)/4);
270 tptr += 4*((name_len + 3)/4);
271
272 /* TLV information follows */
273
274 while (len > 0) {
275
276 /*
277 * Cisco specs say 2 bytes for type + 2 bytes for length;
278 * see https://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
279 * However, actual packets on the wire appear to use 1
280 * byte for the type and 1 byte for the length, so that's
281 * what we do.
282 */
283 if (len < 2)
284 goto invalid;
285 type = GET_U_1(tptr);
286 tlv_len = GET_U_1(tptr + 1);
287
288 ND_PRINT("\n\t\t%s (0x%04x) TLV",
289 tok2str(vtp_vlan_tlv_values, "Unknown", type),
290 type);
291
292 if (len < tlv_len * 2 + 2) {
293 ND_PRINT(" (TLV goes past the end of the packet)");
294 goto invalid;
295 }
296 ND_TCHECK_LEN(tptr, tlv_len * 2 + 2);
297
298 /*
299 * We assume the value is a 2-byte integer; the length is
300 * in units of 16-bit words.
301 */
302 if (tlv_len != 1) {
303 ND_PRINT(" (invalid TLV length %u != 1)", tlv_len);
304 goto invalid;
305 } else {
306 tlv_value = GET_BE_U_2(tptr + 2);
307
308 switch (type) {
309 case VTP_VLAN_STE_HOP_COUNT:
310 ND_PRINT(", %u", tlv_value);
311 break;
312
313 case VTP_VLAN_PRUNING:
314 ND_PRINT(", %s (%u)",
315 tlv_value == 1 ? "Enabled" : "Disabled",
316 tlv_value);
317 break;
318
319 case VTP_VLAN_STP_TYPE:
320 ND_PRINT(", %s (%u)",
321 tok2str(vtp_stp_type_values, "Unknown", tlv_value),
322 tlv_value);
323 break;
324
325 case VTP_VLAN_BRIDGE_TYPE:
326 ND_PRINT(", %s (%u)",
327 tlv_value == 1 ? "SRB" : "SRT",
328 tlv_value);
329 break;
330
331 case VTP_VLAN_BACKUP_CRF_MODE:
332 ND_PRINT(", %s (%u)",
333 tlv_value == 1 ? "Backup" : "Not backup",
334 tlv_value);
335 break;
336
337 /*
338 * FIXME those are the defined TLVs that lack a decoder
339 * you are welcome to contribute code ;-)
340 */
341
342 case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER:
343 case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER:
344 case VTP_VLAN_PARENT_VLAN:
345 case VTP_VLAN_TRANS_BRIDGED_VLAN:
346 case VTP_VLAN_ARP_HOP_COUNT:
347 default:
348 print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2);
349 break;
350 }
351 }
352 len -= 2 + tlv_len*2;
353 tptr += 2 + tlv_len*2;
354 }
355 }
356 break;
357
358 case VTP_ADV_REQUEST:
359
360 /*
361 * ADVERTISEMENT REQUEST
362 *
363 * 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
364 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
365 * | Version | Code | Reserved | MgmtD Len |
366 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
367 * | Management Domain Name (zero-padded to 32 bytes) |
368 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
369 * | Start value |
370 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
371 *
372 */
373
374 ND_PRINT("\n\tStart value: %u", GET_BE_U_4(tptr));
375 break;
376
377 case VTP_JOIN_MESSAGE:
378
379 /* FIXME - Could not find message format */
380 break;
381
382 default:
383 break;
384 }
385
386 return;
387
388 invalid:
389 nd_print_invalid(ndo);
390 tcheck_full_packet:
391 ND_TCHECK_LEN(pptr, length);
392 }
393