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 * Format and print IEEE 802.1d spanning tree protocol packets.
9 * Contributed by Lennert Buytenhek <buytenh@gnu.org>
10 */
11
12 #define NETDISSECT_REWORKED
13 #ifdef HAVE_CONFIG_H
14 #include "config.h"
15 #endif
16
17 #include <tcpdump-stdinc.h>
18
19 #include <stdio.h>
20
21 #include "interface.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 static char *
stp_print_bridge_id(const u_char * p)88 stp_print_bridge_id(const u_char *p)
89 {
90 static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")];
91
92 snprintf(bridge_id_str, sizeof(bridge_id_str),
93 "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
94 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
95
96 return bridge_id_str;
97 }
98
99 static void
stp_print_config_bpdu(netdissect_options * ndo,const struct stp_bpdu_ * stp_bpdu,u_int length)100 stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
101 u_int length)
102 {
103 ND_PRINT((ndo, ", Flags [%s]",
104 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags)));
105
106 ND_PRINT((ndo, ", bridge-id %s.%04x, length %u",
107 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id),
108 EXTRACT_16BITS(&stp_bpdu->port_id), length));
109
110 /* in non-verbose mode just print the bridge-id */
111 if (!ndo->ndo_vflag) {
112 return;
113 }
114
115 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs"
116 ", hello-time %.2fs, forwarding-delay %.2fs",
117 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
118 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
119 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
120 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE));
121
122 ND_PRINT((ndo, "\n\troot-id %s, root-pathcost %u",
123 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
124 EXTRACT_32BITS(&stp_bpdu->root_path_cost)));
125
126 /* Port role is only valid for 802.1w */
127 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
128 ND_PRINT((ndo, ", port-role %s",
129 tok2str(rstp_obj_port_role_values, "Unknown",
130 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))));
131 }
132 }
133
134 /*
135 * MSTP packet format
136 * Ref. IEEE 802.1Q 2003 Ed. Section 14
137 *
138 * MSTP BPDU
139 *
140 * 2 - bytes Protocol Id
141 * 1 - byte Protocol Ver.
142 * 1 - byte BPDU tye
143 * 1 - byte Flags
144 * 8 - bytes CIST Root Identifier
145 * 4 - bytes CIST External Path Cost
146 * 8 - bytes CIST Regional Root Identifier
147 * 2 - bytes CIST Port Identifier
148 * 2 - bytes Message Age
149 * 2 - bytes Max age
150 * 2 - bytes Hello Time
151 * 2 - bytes Forward delay
152 * 1 - byte Version 1 length. Must be 0
153 * 2 - bytes Version 3 length
154 * 1 - byte Config Identifier
155 * 32 - bytes Config Name
156 * 2 - bytes Revision level
157 * 16 - bytes Config Digest [MD5]
158 * 4 - bytes CIST Internal Root Path Cost
159 * 8 - bytes CIST Bridge Identifier
160 * 1 - byte CIST Remaining Hops
161 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes]
162 *
163 *
164 * SPB BPDU
165 * Ref. IEEE 802.1aq. Section 14
166 *
167 * 2 - bytes Version 4 length
168 * 1 - byte Aux Config Identifier
169 * 32 - bytes Aux Config Name
170 * 2 - bytes Aux Revision level
171 * 16 - bytes Aux Config Digest [MD5]
172 * 1 - byte (1 - 2) Agreement Number
173 * (3 - 4) Discarded Agreement Number
174 * (5) Agreement Valid Flag
175 * (6) Restricted Role Flag
176 * (7 - 8) Unused sent zero
177 * 1 - byte Unused
178 * 1 - byte (1 - 4) Agreement Digest Format Identifier
179 * (5 - 8) Agreement Digest Format Capabilities
180 * 1 - byte (1 - 4) Agreement Digest Convention Identifier
181 * (5 - 8) Agreement Digest Convention Capabilities
182 * 2 - bytes Agreement Digest Edge Count
183 * 8 - byte Reserved Set
184 * 20 - bytes Computed Topology Digest
185 *
186 *
187 * MSTI Payload
188 *
189 * 1 - byte MSTI flag
190 * 8 - bytes MSTI Regional Root Identifier
191 * 4 - bytes MSTI Regional Path Cost
192 * 1 - byte MSTI Bridge Priority
193 * 1 - byte MSTI Port Priority
194 * 1 - byte MSTI Remaining Hops
195 *
196 */
197
198 #define MST_BPDU_MSTI_LENGTH 16
199 #define MST_BPDU_CONFIG_INFO_LENGTH 64
200
201 /* Offsets of fields from the begginning for the packet */
202 #define MST_BPDU_VER3_LEN_OFFSET 36
203 #define MST_BPDU_CONFIG_NAME_OFFSET 39
204 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73
205 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89
206 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93
207 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101
208 #define MST_BPDU_MSTI_OFFSET 102
209 /* Offsets within an MSTI */
210 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1
211 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9
212 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13
213 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14
214 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15
215
216 #define SPB_BPDU_MIN_LEN 87
217 #define SPB_BPDU_CONFIG_NAME_OFFSET 3
218 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32
219 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2
220 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16
221 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1
222 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1
223 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1
224 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1
225 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2
226 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4
227 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4
228
229
230 static void
stp_print_mstp_bpdu(netdissect_options * ndo,const struct stp_bpdu_ * stp_bpdu,u_int length)231 stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
232 u_int length)
233 {
234 const u_char *ptr;
235 uint16_t v3len;
236 uint16_t len;
237 uint16_t msti;
238 u_int offset;
239
240 ptr = (const u_char *)stp_bpdu;
241 ND_PRINT((ndo, ", CIST Flags [%s], length %u",
242 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags), length));
243
244 /*
245 * in non-verbose mode just print the flags.
246 */
247 if (!ndo->ndo_vflag) {
248 return;
249 }
250
251 ND_PRINT((ndo, "\n\tport-role %s, ",
252 tok2str(rstp_obj_port_role_values, "Unknown",
253 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))));
254
255 ND_PRINT((ndo, "CIST root-id %s, CIST ext-pathcost %u ",
256 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
257 EXTRACT_32BITS(&stp_bpdu->root_path_cost)));
258
259 ND_PRINT((ndo, "\n\tCIST regional-root-id %s, ",
260 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id)));
261
262 ND_PRINT((ndo, "CIST port-id %04x, ", EXTRACT_16BITS(&stp_bpdu->port_id)));
263
264 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs"
265 ", hello-time %.2fs, forwarding-delay %.2fs",
266 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
267 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
268 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
269 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE));
270
271 ND_PRINT((ndo, "\n\tv3len %d, ", EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET)));
272 ND_PRINT((ndo, "MCID Name %s, rev %u, "
273 "\n\t\tdigest %08x%08x%08x%08x, ",
274 ptr + MST_BPDU_CONFIG_NAME_OFFSET,
275 EXTRACT_16BITS(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32),
276 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET),
277 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4),
278 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8),
279 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12)));
280
281 ND_PRINT((ndo, "CIST int-root-pathcost %u, ",
282 EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET)));
283
284 ND_PRINT((ndo, "\n\tCIST bridge-id %s, ",
285 stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET)));
286
287 ND_PRINT((ndo, "CIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]));
288
289 /* Dump all MSTI's */
290 v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET);
291 if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) {
292 len = v3len - MST_BPDU_CONFIG_INFO_LENGTH;
293 offset = MST_BPDU_MSTI_OFFSET;
294 while (len >= MST_BPDU_MSTI_LENGTH) {
295 msti = EXTRACT_16BITS(ptr + offset +
296 MST_BPDU_MSTI_ROOT_PRIO_OFFSET);
297 msti = msti & 0x0FFF;
298
299 ND_PRINT((ndo, "\n\tMSTI %d, Flags [%s], port-role %s",
300 msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]),
301 tok2str(rstp_obj_port_role_values, "Unknown",
302 RSTP_EXTRACT_PORT_ROLE(ptr[offset]))));
303 ND_PRINT((ndo, "\n\t\tMSTI regional-root-id %s, pathcost %u",
304 stp_print_bridge_id(ptr + offset +
305 MST_BPDU_MSTI_ROOT_PRIO_OFFSET),
306 EXTRACT_32BITS(ptr + offset +
307 MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET)));
308 ND_PRINT((ndo, "\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d",
309 ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET] >> 4,
310 ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET] >> 4,
311 ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET]));
312
313 len -= MST_BPDU_MSTI_LENGTH;
314 offset += MST_BPDU_MSTI_LENGTH;
315 }
316 }
317 }
318
319 static void
stp_print_spb_bpdu(netdissect_options * ndo,const struct stp_bpdu_ * stp_bpdu,u_int offset)320 stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
321 u_int offset)
322 {
323 const u_char *ptr;
324
325 /*
326 * in non-verbose mode don't print anything.
327 */
328 if (!ndo->ndo_vflag) {
329 return;
330 }
331
332 ptr = (const u_char *)stp_bpdu;
333 ND_PRINT((ndo, "\n\tv4len %d AUXMCID Name %s, Rev %u, \n\t\tdigest %08x%08x%08x%08x",
334 EXTRACT_16BITS (ptr + offset),
335 ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET,
336 EXTRACT_16BITS(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET),
337 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET),
338 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4),
339 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8),
340 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12)));
341
342 ND_PRINT((ndo, "\n\tAgreement num %d, Discarded Agreement num %d, Agreement valid-"
343 "flag %d, \n\tRestricted role-flag: %d, Format id %d cap %d, "
344 "Convention id %d cap %d, \n\tEdge count %d, "
345 "Agreement digest %08x%08x%08x%08x%08x\n",
346 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>6,
347 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>4 & 0x3,
348 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>3 & 0x1,
349 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>2 & 0x1,
350 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]>>4,
351 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]&0x00ff,
352 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]>>4,
353 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]&0x00ff,
354 EXTRACT_16BITS(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET),
355 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET),
356 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+4,
357 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+8,
358 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+12,
359 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+16));
360 }
361
362 /*
363 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets.
364 */
365 void
stp_print(netdissect_options * ndo,const u_char * p,u_int length)366 stp_print(netdissect_options *ndo, const u_char *p, u_int length)
367 {
368 const struct stp_bpdu_ *stp_bpdu;
369 u_int mstp_len;
370 u_int spb_len;
371
372 stp_bpdu = (struct stp_bpdu_*)p;
373
374 /* Minimum STP Frame size. */
375 if (length < 4)
376 goto trunc;
377
378 if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) {
379 ND_PRINT((ndo, "unknown STP version, length %u", length));
380 return;
381 }
382
383 ND_PRINT((ndo, "STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
384 stp_bpdu->protocol_version)));
385
386 switch (stp_bpdu->protocol_version) {
387 case STP_PROTO_REGULAR:
388 case STP_PROTO_RAPID:
389 case STP_PROTO_MSTP:
390 case STP_PROTO_SPB:
391 break;
392 default:
393 return;
394 }
395
396 ND_PRINT((ndo, ", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
397 stp_bpdu->bpdu_type)));
398
399 switch (stp_bpdu->bpdu_type) {
400 case STP_BPDU_TYPE_CONFIG:
401 if (length < sizeof(struct stp_bpdu_) - 1) {
402 goto trunc;
403 }
404 stp_print_config_bpdu(ndo, stp_bpdu, length);
405 break;
406
407 case STP_BPDU_TYPE_RSTP:
408 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
409 if (length < sizeof(struct stp_bpdu_)) {
410 goto trunc;
411 }
412 stp_print_config_bpdu(ndo, stp_bpdu, length);
413 } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP ||
414 stp_bpdu->protocol_version == STP_PROTO_SPB) {
415 if (length < STP_BPDU_MSTP_MIN_LEN) {
416 goto trunc;
417 }
418
419 if (stp_bpdu->v1_length != 0) {
420 /* FIX ME: Emit a message here ? */
421 goto trunc;
422 }
423
424 /* Validate v3 length */
425 mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET);
426 mstp_len += 2; /* length encoding itself is 2 bytes */
427 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) {
428 goto trunc;
429 }
430 stp_print_mstp_bpdu(ndo, stp_bpdu, length);
431
432 if (stp_bpdu->protocol_version == STP_PROTO_SPB)
433 {
434 /* Validate v4 length */
435 spb_len = EXTRACT_16BITS (p + MST_BPDU_VER3_LEN_OFFSET + mstp_len);
436 spb_len += 2;
437 if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) ||
438 spb_len < SPB_BPDU_MIN_LEN) {
439 goto trunc;
440 }
441 stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len));
442 }
443 }
444 break;
445
446 case STP_BPDU_TYPE_TOPO_CHANGE:
447 /* always empty message - just break out */
448 break;
449
450 default:
451 break;
452 }
453
454 return;
455 trunc:
456 ND_PRINT((ndo, "[|stp %d]", length));
457 }
458
459 /*
460 * Local Variables:
461 * c-style: whitesmith
462 * c-basic-offset: 4
463 * End:
464 */
465