print-vtp.c revision 356341 
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
45struct 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
55static 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
63static 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
71static 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
80static 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
97static 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
111static const struct tok vtp_stp_type_values[] = {
112    { 1, "SRT"},
113    { 2, "SRB"},
114    { 3, "Auto"},
115    { 0, NULL }
116};
117
118void
119vtp_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 ((unsigned)(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