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 #include <sys/cdefs.h>
23 #ifndef lint
24 __RCSID("$NetBSD: print-vtp.c,v 1.7 2024/09/02 16:15:33 christos Exp $");
25 #endif
26
27 /* \summary: Cisco VLAN Trunking Protocol (VTP) printer */
28
29 #include <config.h>
30
31 #include "netdissect-stdinc.h"
32
33 #define ND_LONGJMP_FROM_TCHECK
34 #include "netdissect.h"
35 #include "addrtoname.h"
36 #include "extract.h"
37
38 #define VTP_HEADER_LEN 36
39 #define VTP_DOMAIN_NAME_LEN 32
40 #define VTP_MD5_DIGEST_LEN 16
41 #define VTP_UPDATE_TIMESTAMP_LEN 12
42 #define VTP_VLAN_INFO_FIXED_PART_LEN 12 /* length of VLAN info before VLAN name */
43
44 #define VTP_SUMMARY_ADV 0x01
45 #define VTP_SUBSET_ADV 0x02
46 #define VTP_ADV_REQUEST 0x03
47 #define VTP_JOIN_MESSAGE 0x04
48
49 struct vtp_vlan_ {
50 nd_uint8_t len;
51 nd_uint8_t status;
52 nd_uint8_t type;
53 nd_uint8_t name_len;
54 nd_uint16_t vlanid;
55 nd_uint16_t mtu;
56 nd_uint32_t index;
57 };
58
59 static const struct tok vtp_message_type_values[] = {
60 { VTP_SUMMARY_ADV, "Summary advertisement"},
61 { VTP_SUBSET_ADV, "Subset advertisement"},
62 { VTP_ADV_REQUEST, "Advertisement request"},
63 { VTP_JOIN_MESSAGE, "Join message"},
64 { 0, NULL }
65 };
66
67 static const struct tok vtp_header_values[] = {
68 { 0x01, "Followers"}, /* On Summary advertisement, 3rd byte is Followers */
69 { 0x02, "Seq number"}, /* On Subset advertisement, 3rd byte is Sequence number */
70 { 0x03, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
71 { 0x04, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
72 { 0, NULL }
73 };
74
75 static const struct tok vtp_vlan_type_values[] = {
76 { 0x01, "Ethernet"},
77 { 0x02, "FDDI"},
78 { 0x03, "TrCRF"},
79 { 0x04, "FDDI-net"},
80 { 0x05, "TrBRF"},
81 { 0, NULL }
82 };
83
84 static const struct tok vtp_vlan_status[] = {
85 { 0x00, "Operational"},
86 { 0x01, "Suspended"},
87 { 0, NULL }
88 };
89
90 #define VTP_VLAN_SOURCE_ROUTING_RING_NUMBER 0x01
91 #define VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER 0x02
92 #define VTP_VLAN_STP_TYPE 0x03
93 #define VTP_VLAN_PARENT_VLAN 0x04
94 #define VTP_VLAN_TRANS_BRIDGED_VLAN 0x05
95 #define VTP_VLAN_PRUNING 0x06
96 #define VTP_VLAN_BRIDGE_TYPE 0x07
97 #define VTP_VLAN_ARP_HOP_COUNT 0x08
98 #define VTP_VLAN_STE_HOP_COUNT 0x09
99 #define VTP_VLAN_BACKUP_CRF_MODE 0x0A
100
101 static const struct tok vtp_vlan_tlv_values[] = {
102 { VTP_VLAN_SOURCE_ROUTING_RING_NUMBER, "Source-Routing Ring Number TLV"},
103 { VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER, "Source-Routing Bridge Number TLV"},
104 { VTP_VLAN_STP_TYPE, "STP type TLV"},
105 { VTP_VLAN_PARENT_VLAN, "Parent VLAN TLV"},
106 { VTP_VLAN_TRANS_BRIDGED_VLAN, "Translationally bridged VLANs TLV"},
107 { VTP_VLAN_PRUNING, "Pruning TLV"},
108 { VTP_VLAN_BRIDGE_TYPE, "Bridge Type TLV"},
109 { VTP_VLAN_ARP_HOP_COUNT, "Max ARP Hop Count TLV"},
110 { VTP_VLAN_STE_HOP_COUNT, "Max STE Hop Count TLV"},
111 { VTP_VLAN_BACKUP_CRF_MODE, "Backup CRF Mode TLV"},
112 { 0, NULL }
113 };
114
115 static const struct tok vtp_stp_type_values[] = {
116 { 1, "SRT"},
117 { 2, "SRB"},
118 { 3, "Auto"},
119 { 0, NULL }
120 };
121
122 void
vtp_print(netdissect_options * ndo,const u_char * pptr,const u_int length)123 vtp_print(netdissect_options *ndo,
124 const u_char *pptr, const u_int length)
125 {
126 u_int type, len, name_len, tlv_len, tlv_value, mgmtd_len;
127 const u_char *tptr;
128 const struct vtp_vlan_ *vtp_vlan;
129
130 ndo->ndo_protocol = "vtp";
131 if (length < VTP_HEADER_LEN)
132 goto invalid;
133
134 tptr = pptr;
135
136 ND_TCHECK_LEN(tptr, VTP_HEADER_LEN);
137
138 type = GET_U_1(tptr + 1);
139 ND_PRINT("VTPv%u, Message %s (0x%02x), length %u",
140 GET_U_1(tptr),
141 tok2str(vtp_message_type_values,"Unknown message type", type),
142 type,
143 length);
144
145 /* In non-verbose mode, just print version and message type */
146 if (ndo->ndo_vflag < 1) {
147 goto tcheck_full_packet;
148 }
149
150 /* verbose mode print all fields */
151 ND_PRINT("\n\tDomain name: ");
152 mgmtd_len = GET_U_1(tptr + 3);
153 if (mgmtd_len < 1 || mgmtd_len > VTP_DOMAIN_NAME_LEN) {
154 ND_PRINT(" [MgmtD Len %u]", mgmtd_len);
155 goto invalid;
156 }
157 nd_printjnp(ndo, tptr + 4, mgmtd_len);
158 ND_PRINT(", %s: %u",
159 tok2str(vtp_header_values, "Unknown", type),
160 GET_U_1(tptr + 2));
161
162 tptr += VTP_HEADER_LEN;
163
164 switch (type) {
165
166 case VTP_SUMMARY_ADV:
167
168 /*
169 * SUMMARY ADVERTISEMENT
170 *
171 * 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
172 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
173 * | Version | Code | Followers | MgmtD Len |
174 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
175 * | Management Domain Name (zero-padded to 32 bytes) |
176 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
177 * | Configuration revision number |
178 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
179 * | Updater Identity IP address |
180 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
181 * | Update Timestamp (12 bytes) |
182 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
183 * | MD5 digest (16 bytes) |
184 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
185 *
186 */
187
188 ND_PRINT("\n\t Config Rev %x, Updater %s",
189 GET_BE_U_4(tptr),
190 GET_IPADDR_STRING(tptr+4));
191 tptr += 8;
192 ND_PRINT(", Timestamp 0x%08x 0x%08x 0x%08x",
193 GET_BE_U_4(tptr),
194 GET_BE_U_4(tptr + 4),
195 GET_BE_U_4(tptr + 8));
196 tptr += VTP_UPDATE_TIMESTAMP_LEN;
197 ND_PRINT(", MD5 digest: %08x%08x%08x%08x",
198 GET_BE_U_4(tptr),
199 GET_BE_U_4(tptr + 4),
200 GET_BE_U_4(tptr + 8),
201 GET_BE_U_4(tptr + 12));
202 tptr += VTP_MD5_DIGEST_LEN;
203 break;
204
205 case VTP_SUBSET_ADV:
206
207 /*
208 * SUBSET ADVERTISEMENT
209 *
210 * 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
211 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
212 * | Version | Code | Seq number | MgmtD Len |
213 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
214 * | Management Domain Name (zero-padded to 32 bytes) |
215 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
216 * | Configuration revision number |
217 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
218 * | VLAN info field 1 |
219 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
220 * | ................ |
221 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
222 * | VLAN info field N |
223 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
224 *
225 */
226
227 ND_PRINT(", Config Rev %x", GET_BE_U_4(tptr));
228
229 /*
230 * VLAN INFORMATION
231 * 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
232 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
233 * | V info len | Status | VLAN type | VLAN name len |
234 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
235 * | ISL vlan id | MTU size |
236 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
237 * | 802.10 index (SAID) |
238 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
239 * | VLAN name |
240 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
241 *
242 */
243
244 tptr += 4;
245 while ((unsigned)(tptr - pptr) < length) {
246
247 len = GET_U_1(tptr);
248 if (len == 0)
249 break;
250
251 ND_TCHECK_LEN(tptr, len);
252
253 vtp_vlan = (const struct vtp_vlan_*)tptr;
254 if (len < VTP_VLAN_INFO_FIXED_PART_LEN)
255 goto invalid;
256 ND_PRINT("\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ",
257 tok2str(vtp_vlan_status,"Unknown",GET_U_1(vtp_vlan->status)),
258 tok2str(vtp_vlan_type_values,"Unknown",GET_U_1(vtp_vlan->type)),
259 GET_BE_U_2(vtp_vlan->vlanid),
260 GET_BE_U_2(vtp_vlan->mtu),
261 GET_BE_U_4(vtp_vlan->index));
262 len -= VTP_VLAN_INFO_FIXED_PART_LEN;
263 tptr += VTP_VLAN_INFO_FIXED_PART_LEN;
264 name_len = GET_U_1(vtp_vlan->name_len);
265 if (len < 4*((name_len + 3)/4))
266 goto invalid;
267 nd_printjnp(ndo, tptr, name_len);
268
269 /*
270 * Vlan names are aligned to 32-bit boundaries.
271 */
272 len -= 4*((name_len + 3)/4);
273 tptr += 4*((name_len + 3)/4);
274
275 /* TLV information follows */
276
277 while (len > 0) {
278
279 /*
280 * Cisco specs say 2 bytes for type + 2 bytes for length;
281 * see https://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
282 * However, actual packets on the wire appear to use 1
283 * byte for the type and 1 byte for the length, so that's
284 * what we do.
285 */
286 if (len < 2)
287 goto invalid;
288 type = GET_U_1(tptr);
289 tlv_len = GET_U_1(tptr + 1);
290
291 ND_PRINT("\n\t\t%s (0x%04x) TLV",
292 tok2str(vtp_vlan_tlv_values, "Unknown", type),
293 type);
294
295 if (len < tlv_len * 2 + 2) {
296 ND_PRINT(" (TLV goes past the end of the packet)");
297 goto invalid;
298 }
299 ND_TCHECK_LEN(tptr, tlv_len * 2 + 2);
300
301 /*
302 * We assume the value is a 2-byte integer; the length is
303 * in units of 16-bit words.
304 */
305 if (tlv_len != 1) {
306 ND_PRINT(" [TLV length %u != 1]", tlv_len);
307 goto invalid;
308 } else {
309 tlv_value = GET_BE_U_2(tptr + 2);
310
311 switch (type) {
312 case VTP_VLAN_STE_HOP_COUNT:
313 ND_PRINT(", %u", tlv_value);
314 break;
315
316 case VTP_VLAN_PRUNING:
317 ND_PRINT(", %s (%u)",
318 tlv_value == 1 ? "Enabled" : "Disabled",
319 tlv_value);
320 break;
321
322 case VTP_VLAN_STP_TYPE:
323 ND_PRINT(", %s (%u)",
324 tok2str(vtp_stp_type_values, "Unknown", tlv_value),
325 tlv_value);
326 break;
327
328 case VTP_VLAN_BRIDGE_TYPE:
329 ND_PRINT(", %s (%u)",
330 tlv_value == 1 ? "SRB" : "SRT",
331 tlv_value);
332 break;
333
334 case VTP_VLAN_BACKUP_CRF_MODE:
335 ND_PRINT(", %s (%u)",
336 tlv_value == 1 ? "Backup" : "Not backup",
337 tlv_value);
338 break;
339
340 /*
341 * FIXME those are the defined TLVs that lack a decoder
342 * you are welcome to contribute code ;-)
343 */
344
345 case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER:
346 case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER:
347 case VTP_VLAN_PARENT_VLAN:
348 case VTP_VLAN_TRANS_BRIDGED_VLAN:
349 case VTP_VLAN_ARP_HOP_COUNT:
350 default:
351 print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2);
352 break;
353 }
354 }
355 len -= 2 + tlv_len*2;
356 tptr += 2 + tlv_len*2;
357 }
358 }
359 break;
360
361 case VTP_ADV_REQUEST:
362
363 /*
364 * ADVERTISEMENT REQUEST
365 *
366 * 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
367 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
368 * | Version | Code | Reserved | MgmtD Len |
369 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
370 * | Management Domain Name (zero-padded to 32 bytes) |
371 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
372 * | Start value |
373 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
374 *
375 */
376
377 ND_PRINT("\n\tStart value: %u", GET_BE_U_4(tptr));
378 break;
379
380 case VTP_JOIN_MESSAGE:
381
382 /* FIXME - Could not find message format */
383 break;
384
385 default:
386 break;
387 }
388
389 return;
390
391 invalid:
392 nd_print_invalid(ndo);
393 tcheck_full_packet:
394 ND_TCHECK_LEN(pptr, length);
395 }
396