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
46struct 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
56static 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
64static 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
72static 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
81static 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
98static 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
112static const struct tok vtp_stp_type_values[] = {
113    { 1, "SRT"},
114    { 2, "SRB"},
115    { 3, "Auto"},
116    { 0, NULL }
117};
118
119void
120vtp_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
388invalid:
389    nd_print_invalid(ndo);
390tcheck_full_packet:
391    ND_TCHECK_LEN(pptr, length);
392}
393