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[tcpdump] / print-stp.c
1 /*
2 * Copyright (c) 2000 Lennert Buytenhek
3 *
4 * This software may be distributed either under the terms of the
5 * BSD-style license that accompanies tcpdump or the GNU General
6 * Public License
7 *
8 * Contributed by Lennert Buytenhek <buytenh@gnu.org>
9 */
10
11 /* \summary: IEEE 802.1d Spanning Tree Protocol (STP) printer */
12
13 #ifdef HAVE_CONFIG_H
14 #include "config.h"
15 #endif
16
17 #include <netdissect-stdinc.h>
18
19 #include <stdio.h>
20
21 #include "netdissect.h"
22 #include "extract.h"
23
24 #define RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2)
25 /* STP timers are expressed in multiples of 1/256th second */
26 #define STP_TIME_BASE 256
27 #define STP_BPDU_MSTP_MIN_LEN 102
28
29 struct stp_bpdu_ {
30 uint8_t protocol_id[2];
31 uint8_t protocol_version;
32 uint8_t bpdu_type;
33 uint8_t flags;
34 uint8_t root_id[8];
35 uint8_t root_path_cost[4];
36 uint8_t bridge_id[8];
37 uint8_t port_id[2];
38 uint8_t message_age[2];
39 uint8_t max_age[2];
40 uint8_t hello_time[2];
41 uint8_t forward_delay[2];
42 uint8_t v1_length;
43 };
44
45 #define STP_PROTO_REGULAR 0x00
46 #define STP_PROTO_RAPID 0x02
47 #define STP_PROTO_MSTP 0x03
48 #define STP_PROTO_SPB 0x04
49
50 static const struct tok stp_proto_values[] = {
51 { STP_PROTO_REGULAR, "802.1d" },
52 { STP_PROTO_RAPID, "802.1w" },
53 { STP_PROTO_MSTP, "802.1s" },
54 { STP_PROTO_SPB, "802.1aq" },
55 { 0, NULL}
56 };
57
58 #define STP_BPDU_TYPE_CONFIG 0x00
59 #define STP_BPDU_TYPE_RSTP 0x02
60 #define STP_BPDU_TYPE_TOPO_CHANGE 0x80
61
62 static const struct tok stp_bpdu_flag_values[] = {
63 { 0x01, "Topology change" },
64 { 0x02, "Proposal" },
65 { 0x10, "Learn" },
66 { 0x20, "Forward" },
67 { 0x40, "Agreement" },
68 { 0x80, "Topology change ACK" },
69 { 0, NULL}
70 };
71
72 static const struct tok stp_bpdu_type_values[] = {
73 { STP_BPDU_TYPE_CONFIG, "Config" },
74 { STP_BPDU_TYPE_RSTP, "Rapid STP" },
75 { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" },
76 { 0, NULL}
77 };
78
79 static const struct tok rstp_obj_port_role_values[] = {
80 { 0x00, "Unknown" },
81 { 0x01, "Alternate" },
82 { 0x02, "Root" },
83 { 0x03, "Designated" },
84 { 0, NULL}
85 };
86
87 #define ND_TCHECK_BRIDGE_ID(p) ND_TCHECK_8(p)
88
89 static char *
90 stp_print_bridge_id(const u_char *p)
91 {
92 static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")];
93
94 snprintf(bridge_id_str, sizeof(bridge_id_str),
95 "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
96 EXTRACT_U_1(p), EXTRACT_U_1(p + 1), EXTRACT_U_1(p + 2),
97 EXTRACT_U_1(p + 3), EXTRACT_U_1(p + 4), EXTRACT_U_1(p + 5),
98 EXTRACT_U_1(p + 6), EXTRACT_U_1(p + 7));
99
100 return bridge_id_str;
101 }
102
103 static int
104 stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
105 u_int length)
106 {
107 ND_TCHECK(stp_bpdu->flags);
108 ND_PRINT((ndo, ", Flags [%s]",
109 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags)));
110
111 ND_TCHECK(stp_bpdu->port_id);
112 ND_PRINT((ndo, ", bridge-id %s.%04x, length %u",
113 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id),
114 EXTRACT_BE_U_2(&stp_bpdu->port_id), length));
115
116 /* in non-verbose mode just print the bridge-id */
117 if (!ndo->ndo_vflag) {
118 return 1;
119 }
120
121 ND_TCHECK(stp_bpdu->forward_delay);
122 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs"
123 ", hello-time %.2fs, forwarding-delay %.2fs",
124 (float) EXTRACT_BE_U_2(&stp_bpdu->message_age) / STP_TIME_BASE,
125 (float) EXTRACT_BE_U_2(&stp_bpdu->max_age) / STP_TIME_BASE,
126 (float) EXTRACT_BE_U_2(&stp_bpdu->hello_time) / STP_TIME_BASE,
127 (float) EXTRACT_BE_U_2(&stp_bpdu->forward_delay) / STP_TIME_BASE));
128
129 ND_PRINT((ndo, "\n\troot-id %s, root-pathcost %u",
130 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
131 EXTRACT_BE_U_4(&stp_bpdu->root_path_cost)));
132
133 /* Port role is only valid for 802.1w */
134 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
135 ND_PRINT((ndo, ", port-role %s",
136 tok2str(rstp_obj_port_role_values, "Unknown",
137 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))));
138 }
139 return 1;
140
141 trunc:
142 return 0;
143 }
144
145 /*
146 * MSTP packet format
147 * Ref. IEEE 802.1Q 2003 Ed. Section 14
148 *
149 * MSTP BPDU
150 *
151 * 2 - bytes Protocol Id
152 * 1 - byte Protocol Ver.
153 * 1 - byte BPDU tye
154 * 1 - byte Flags
155 * 8 - bytes CIST Root Identifier
156 * 4 - bytes CIST External Path Cost
157 * 8 - bytes CIST Regional Root Identifier
158 * 2 - bytes CIST Port Identifier
159 * 2 - bytes Message Age
160 * 2 - bytes Max age
161 * 2 - bytes Hello Time
162 * 2 - bytes Forward delay
163 * 1 - byte Version 1 length. Must be 0
164 * 2 - bytes Version 3 length
165 * 1 - byte Config Identifier
166 * 32 - bytes Config Name
167 * 2 - bytes Revision level
168 * 16 - bytes Config Digest [MD5]
169 * 4 - bytes CIST Internal Root Path Cost
170 * 8 - bytes CIST Bridge Identifier
171 * 1 - byte CIST Remaining Hops
172 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes]
173 *
174 *
175 * SPB BPDU
176 * Ref. IEEE 802.1aq. Section 14
177 *
178 * 2 - bytes Version 4 length
179 * 1 - byte Aux Config Identifier
180 * 32 - bytes Aux Config Name
181 * 2 - bytes Aux Revision level
182 * 16 - bytes Aux Config Digest [MD5]
183 * 1 - byte (1 - 2) Agreement Number
184 * (3 - 4) Discarded Agreement Number
185 * (5) Agreement Valid Flag
186 * (6) Restricted Role Flag
187 * (7 - 8) Unused sent zero
188 * 1 - byte Unused
189 * 1 - byte (1 - 4) Agreement Digest Format Identifier
190 * (5 - 8) Agreement Digest Format Capabilities
191 * 1 - byte (1 - 4) Agreement Digest Convention Identifier
192 * (5 - 8) Agreement Digest Convention Capabilities
193 * 2 - bytes Agreement Digest Edge Count
194 * 8 - byte Reserved Set
195 * 20 - bytes Computed Topology Digest
196 *
197 *
198 * MSTI Payload
199 *
200 * 1 - byte MSTI flag
201 * 8 - bytes MSTI Regional Root Identifier
202 * 4 - bytes MSTI Regional Path Cost
203 * 1 - byte MSTI Bridge Priority
204 * 1 - byte MSTI Port Priority
205 * 1 - byte MSTI Remaining Hops
206 *
207 */
208
209 #define MST_BPDU_MSTI_LENGTH 16
210 #define MST_BPDU_CONFIG_INFO_LENGTH 64
211
212 /* Offsets of fields from the begginning for the packet */
213 #define MST_BPDU_VER3_LEN_OFFSET 36
214 #define MST_BPDU_CONFIG_NAME_OFFSET 39
215 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73
216 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89
217 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93
218 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101
219 #define MST_BPDU_MSTI_OFFSET 102
220 /* Offsets within an MSTI */
221 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1
222 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9
223 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13
224 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14
225 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15
226
227 #define SPB_BPDU_MIN_LEN 87
228 #define SPB_BPDU_CONFIG_NAME_OFFSET 3
229 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32
230 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2
231 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16
232 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1
233 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1
234 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1
235 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1
236 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2
237 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4
238 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4
239
240 static int
241 stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
242 u_int length)
243 {
244 const u_char *ptr;
245 uint16_t v3len;
246 uint16_t len;
247 uint16_t msti;
248 u_int offset;
249
250 ptr = (const u_char *)stp_bpdu;
251 ND_PRINT((ndo, ", CIST Flags [%s], length %u",
252 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags), length));
253
254 /*
255 * in non-verbose mode just print the flags.
256 */
257 if (!ndo->ndo_vflag) {
258 return 1;
259 }
260
261 ND_TCHECK(stp_bpdu->flags);
262 ND_PRINT((ndo, "\n\tport-role %s, ",
263 tok2str(rstp_obj_port_role_values, "Unknown",
264 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))));
265
266 ND_TCHECK(stp_bpdu->root_path_cost);
267 ND_PRINT((ndo, "CIST root-id %s, CIST ext-pathcost %u",
268 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
269 EXTRACT_BE_U_4(&stp_bpdu->root_path_cost)));
270
271 ND_TCHECK(stp_bpdu->bridge_id);
272 ND_PRINT((ndo, "\n\tCIST regional-root-id %s, ",
273 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id)));
274
275 ND_TCHECK(stp_bpdu->port_id);
276 ND_PRINT((ndo, "CIST port-id %04x,", EXTRACT_BE_U_2(&stp_bpdu->port_id)));
277
278 ND_TCHECK(stp_bpdu->forward_delay);
279 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs"
280 ", hello-time %.2fs, forwarding-delay %.2fs",
281 (float) EXTRACT_BE_U_2(&stp_bpdu->message_age) / STP_TIME_BASE,
282 (float) EXTRACT_BE_U_2(&stp_bpdu->max_age) / STP_TIME_BASE,
283 (float) EXTRACT_BE_U_2(&stp_bpdu->hello_time) / STP_TIME_BASE,
284 (float) EXTRACT_BE_U_2(&stp_bpdu->forward_delay) / STP_TIME_BASE));
285
286 ND_TCHECK_2(ptr + MST_BPDU_VER3_LEN_OFFSET);
287 ND_PRINT((ndo, "\n\tv3len %d, ", EXTRACT_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET)));
288 ND_TCHECK_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12);
289 ND_PRINT((ndo, "MCID Name "));
290 if (fn_printzp(ndo, ptr + MST_BPDU_CONFIG_NAME_OFFSET, 32, ndo->ndo_snapend))
291 goto trunc;
292 ND_PRINT((ndo, ", rev %u,"
293 "\n\t\tdigest %08x%08x%08x%08x, ",
294 EXTRACT_BE_U_2(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32),
295 EXTRACT_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET),
296 EXTRACT_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4),
297 EXTRACT_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8),
298 EXTRACT_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12)));
299
300 ND_TCHECK_4(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET);
301 ND_PRINT((ndo, "CIST int-root-pathcost %u,",
302 EXTRACT_BE_U_4(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET)));
303
304 ND_TCHECK_BRIDGE_ID(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET);
305 ND_PRINT((ndo, "\n\tCIST bridge-id %s, ",
306 stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET)));
307
308 ND_TCHECK_1(ptr + MST_BPDU_CIST_REMAIN_HOPS_OFFSET);
309 ND_PRINT((ndo, "CIST remaining-hops %d", EXTRACT_U_1(ptr + MST_BPDU_CIST_REMAIN_HOPS_OFFSET)));
310
311 /* Dump all MSTI's */
312 ND_TCHECK_2(ptr + MST_BPDU_VER3_LEN_OFFSET);
313 v3len = EXTRACT_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET);
314 if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) {
315 len = v3len - MST_BPDU_CONFIG_INFO_LENGTH;
316 offset = MST_BPDU_MSTI_OFFSET;
317 while (len >= MST_BPDU_MSTI_LENGTH) {
318 ND_TCHECK_LEN(ptr + offset, MST_BPDU_MSTI_LENGTH);
319
320 msti = EXTRACT_BE_U_2(ptr + offset + MST_BPDU_MSTI_ROOT_PRIO_OFFSET);
321 msti = msti & 0x0FFF;
322
323 ND_PRINT((ndo, "\n\tMSTI %d, Flags [%s], port-role %s",
324 msti, bittok2str(stp_bpdu_flag_values, "none", EXTRACT_U_1(ptr + offset)),
325 tok2str(rstp_obj_port_role_values, "Unknown",
326 RSTP_EXTRACT_PORT_ROLE(EXTRACT_U_1(ptr + offset)))));
327 ND_PRINT((ndo, "\n\t\tMSTI regional-root-id %s, pathcost %u",
328 stp_print_bridge_id(ptr + offset +
329 MST_BPDU_MSTI_ROOT_PRIO_OFFSET),
330 EXTRACT_BE_U_4(ptr + offset + MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET)));
331 ND_PRINT((ndo, "\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d",
332 EXTRACT_U_1(ptr + offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET) >> 4,
333 EXTRACT_U_1(ptr + offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET) >> 4,
334 EXTRACT_U_1(ptr + offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET)));
335
336 len -= MST_BPDU_MSTI_LENGTH;
337 offset += MST_BPDU_MSTI_LENGTH;
338 }
339 }
340 return 1;
341
342 trunc:
343 return 0;
344 }
345
346 static int
347 stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
348 u_int offset)
349 {
350 const u_char *ptr;
351
352 /*
353 * in non-verbose mode don't print anything.
354 */
355 if (!ndo->ndo_vflag) {
356 return 1;
357 }
358
359 ptr = (const u_char *)stp_bpdu;
360 ND_TCHECK_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 16);
361
362 ND_PRINT((ndo, "\n\tv4len %d, ", EXTRACT_BE_U_2(ptr + offset)));
363 ND_PRINT((ndo, "AUXMCID Name "));
364 if (fn_printzp(ndo, ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET, 32,
365 ndo->ndo_snapend))
366 goto trunc;
367 ND_PRINT((ndo, ", Rev %u,\n\t\tdigest %08x%08x%08x%08x",
368 EXTRACT_BE_U_2(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET),
369 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET),
370 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4),
371 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8),
372 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12)));
373
374 ND_PRINT((ndo, "\n\tAgreement num %d, Discarded Agreement num %d, Agreement valid-"
375 "flag %d,\n\tRestricted role-flag: %d, Format id %d cap %d, "
376 "Convention id %d cap %d,\n\tEdge count %d, "
377 "Agreement digest %08x%08x%08x%08x%08x\n",
378 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>6,
379 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>4 & 0x3,
380 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>3 & 0x1,
381 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>2 & 0x1,
382 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)>>4,
383 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)&0x00ff,
384 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)>>4,
385 EXTRACT_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)&0x00ff,
386 EXTRACT_BE_U_2(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET),
387 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET),
388 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 4),
389 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 8),
390 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 12),
391 EXTRACT_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 16)));
392 return 1;
393
394 trunc:
395 return 0;
396 }
397
398 /*
399 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets.
400 */
401 void
402 stp_print(netdissect_options *ndo, const u_char *p, u_int length)
403 {
404 const struct stp_bpdu_ *stp_bpdu;
405 u_int mstp_len;
406 u_int spb_len;
407
408 stp_bpdu = (const struct stp_bpdu_*)p;
409
410 /* Minimum STP Frame size. */
411 if (length < 4)
412 goto trunc;
413
414 ND_TCHECK(stp_bpdu->protocol_id);
415 if (EXTRACT_BE_U_2(&stp_bpdu->protocol_id)) {
416 ND_PRINT((ndo, "unknown STP version, length %u", length));
417 return;
418 }
419
420 ND_TCHECK(stp_bpdu->protocol_version);
421 ND_PRINT((ndo, "STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
422 stp_bpdu->protocol_version)));
423
424 switch (stp_bpdu->protocol_version) {
425 case STP_PROTO_REGULAR:
426 case STP_PROTO_RAPID:
427 case STP_PROTO_MSTP:
428 case STP_PROTO_SPB:
429 break;
430 default:
431 return;
432 }
433
434 ND_TCHECK(stp_bpdu->bpdu_type);
435 ND_PRINT((ndo, ", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
436 stp_bpdu->bpdu_type)));
437
438 switch (stp_bpdu->bpdu_type) {
439 case STP_BPDU_TYPE_CONFIG:
440 if (length < sizeof(struct stp_bpdu_) - 1) {
441 goto trunc;
442 }
443 if (!stp_print_config_bpdu(ndo, stp_bpdu, length))
444 goto trunc;
445 break;
446
447 case STP_BPDU_TYPE_RSTP:
448 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
449 if (length < sizeof(struct stp_bpdu_)) {
450 goto trunc;
451 }
452 if (!stp_print_config_bpdu(ndo, stp_bpdu, length))
453 goto trunc;
454 } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP ||
455 stp_bpdu->protocol_version == STP_PROTO_SPB) {
456 if (length < STP_BPDU_MSTP_MIN_LEN) {
457 goto trunc;
458 }
459
460 ND_TCHECK(stp_bpdu->v1_length);
461 if (stp_bpdu->v1_length != 0) {
462 /* FIX ME: Emit a message here ? */
463 goto trunc;
464 }
465
466 /* Validate v3 length */
467 ND_TCHECK_2(p + MST_BPDU_VER3_LEN_OFFSET);
468 mstp_len = EXTRACT_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET);
469 mstp_len += 2; /* length encoding itself is 2 bytes */
470 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) {
471 goto trunc;
472 }
473 if (!stp_print_mstp_bpdu(ndo, stp_bpdu, length))
474 goto trunc;
475
476 if (stp_bpdu->protocol_version == STP_PROTO_SPB)
477 {
478 /* Validate v4 length */
479 ND_TCHECK_2(p + MST_BPDU_VER3_LEN_OFFSET + mstp_len);
480 spb_len = EXTRACT_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET + mstp_len);
481 spb_len += 2;
482 if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) ||
483 spb_len < SPB_BPDU_MIN_LEN) {
484 goto trunc;
485 }
486 if (!stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len)))
487 goto trunc;
488 }
489 }
490 break;
491
492 case STP_BPDU_TYPE_TOPO_CHANGE:
493 /* always empty message - just break out */
494 break;
495
496 default:
497 break;
498 }
499
500 return;
501 trunc:
502 ND_PRINT((ndo, "[|stp %d]", length));
503 }
504
505 /*
506 * Local Variables:
507 * c-style: whitesmith
508 * c-basic-offset: 4
509 * End:
510 */
[mirror] the TCPdump network dissector