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Use EXTRACT_nBITS even when just testing against zero.
[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 * Format and print IEEE 802.1d spanning tree protocol packets.
9 * Contributed by Lennert Buytenhek <buytenh@gnu.org>
10 */
11
12 #ifdef HAVE_CONFIG_H
13 #include "config.h"
14 #endif
15
16 #include <tcpdump-stdinc.h>
17
18 #include <stdlib.h>
19 #include <stdio.h>
20 #include <string.h>
21
22 #include "interface.h"
23 #include "addrtoname.h"
24 #include "extract.h"
25
26 #define RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2)
27 /* STP timers are expressed in multiples of 1/256th second */
28 #define STP_TIME_BASE 256
29 #define STP_BPDU_MSTP_MIN_LEN 102
30
31 struct stp_bpdu_ {
32 u_int8_t protocol_id[2];
33 u_int8_t protocol_version;
34 u_int8_t bpdu_type;
35 u_int8_t flags;
36 u_int8_t root_id[8];
37 u_int8_t root_path_cost[4];
38 u_int8_t bridge_id[8];
39 u_int8_t port_id[2];
40 u_int8_t message_age[2];
41 u_int8_t max_age[2];
42 u_int8_t hello_time[2];
43 u_int8_t forward_delay[2];
44 u_int8_t v1_length;
45 };
46
47 #define STP_PROTO_REGULAR 0x00
48 #define STP_PROTO_RAPID 0x02
49 #define STP_PROTO_MSTP 0x03
50 #define STP_PROTO_SPB 0x04
51
52 static const struct tok stp_proto_values[] = {
53 { STP_PROTO_REGULAR, "802.1d" },
54 { STP_PROTO_RAPID, "802.1w" },
55 { STP_PROTO_MSTP, "802.1s" },
56 { STP_PROTO_SPB, "802.1aq" },
57 { 0, NULL}
58 };
59
60 #define STP_BPDU_TYPE_CONFIG 0x00
61 #define STP_BPDU_TYPE_RSTP 0x02
62 #define STP_BPDU_TYPE_TOPO_CHANGE 0x80
63
64 static const struct tok stp_bpdu_flag_values[] = {
65 { 0x01, "Topology change" },
66 { 0x02, "Proposal" },
67 { 0x10, "Learn" },
68 { 0x20, "Forward" },
69 { 0x40, "Agreement" },
70 { 0x80, "Topology change ACK" },
71 { 0, NULL}
72 };
73
74 static const struct tok stp_bpdu_type_values[] = {
75 { STP_BPDU_TYPE_CONFIG, "Config" },
76 { STP_BPDU_TYPE_RSTP, "Rapid STP" },
77 { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" },
78 { 0, NULL}
79 };
80
81 static const struct tok rstp_obj_port_role_values[] = {
82 { 0x00, "Unknown" },
83 { 0x01, "Alternate" },
84 { 0x02, "Root" },
85 { 0x03, "Designated" },
86 { 0, NULL}
87 };
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 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
97
98 return bridge_id_str;
99 }
100
101 static void
102 stp_print_config_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
103 {
104 printf(", Flags [%s]",
105 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags));
106
107 printf(", bridge-id %s.%04x, length %u",
108 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id),
109 EXTRACT_16BITS(&stp_bpdu->port_id), length);
110
111 /* in non-verbose mode just print the bridge-id */
112 if (!vflag) {
113 return;
114 }
115
116 printf("\n\tmessage-age %.2fs, max-age %.2fs"
117 ", hello-time %.2fs, forwarding-delay %.2fs",
118 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
119 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
120 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
121 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE);
122
123 printf("\n\troot-id %s, root-pathcost %u",
124 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
125 EXTRACT_32BITS(&stp_bpdu->root_path_cost));
126
127 /* Port role is only valid for 802.1w */
128 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
129 printf(", port-role %s",
130 tok2str(rstp_obj_port_role_values, "Unknown",
131 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
132 }
133 }
134
135 /*
136 * MSTP packet format
137 * Ref. IEEE 802.1Q 2003 Ed. Section 14
138 *
139 * MSTP BPDU
140 *
141 * 2 - bytes Protocol Id
142 * 1 - byte Protocol Ver.
143 * 1 - byte BPDU tye
144 * 1 - byte Flags
145 * 8 - bytes CIST Root Identifier
146 * 4 - bytes CIST External Path Cost
147 * 8 - bytes CIST Regional Root Identifier
148 * 2 - bytes CIST Port Identifier
149 * 2 - bytes Message Age
150 * 2 - bytes Max age
151 * 2 - bytes Hello Time
152 * 2 - bytes Forward delay
153 * 1 - byte Version 1 length. Must be 0
154 * 2 - bytes Version 3 length
155 * 1 - byte Config Identifier
156 * 32 - bytes Config Name
157 * 2 - bytes Revision level
158 * 16 - bytes Config Digest [MD5]
159 * 4 - bytes CIST Internal Root Path Cost
160 * 8 - bytes CIST Bridge Identifier
161 * 1 - byte CIST Remaining Hops
162 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes]
163 *
164 *
165 * SPB BPDU
166 * Ref. IEEE 802.1aq. Section 14
167 *
168 * 2 - bytes Version 4 length
169 * 1 - byte Aux Config Identifier
170 * 32 - bytes Aux Config Name
171 * 2 - bytes Aux Revision level
172 * 16 - bytes Aux Config Digest [MD5]
173 * 1 - byte (1 - 2) Agreement Number
174 * (3 - 4) Discarded Agreement Number
175 * (5) Agreement Valid Flag
176 * (6) Restricted Role Flag
177 * (7 - 8) Unused sent zero
178 * 1 - byte Unused
179 * 1 - byte (1 - 4) Agreement Digest Format Identifier
180 * (5 - 8) Agreement Digest Format Capabilities
181 * 1 - byte (1 - 4) Agreement Digest Convention Identifier
182 * (5 - 8) Agreement Digest Convention Capabilities
183 * 2 - bytes Agreement Digest Edge Count
184 * 8 - byte Reserved Set
185 * 20 - bytes Computed Topology Digest
186 *
187 *
188 * MSTI Payload
189 *
190 * 1 - byte MSTI flag
191 * 8 - bytes MSTI Regional Root Identifier
192 * 4 - bytes MSTI Regional Path Cost
193 * 1 - byte MSTI Bridge Priority
194 * 1 - byte MSTI Port Priority
195 * 1 - byte MSTI Remaining Hops
196 *
197 */
198
199 #define MST_BPDU_MSTI_LENGTH 16
200 #define MST_BPDU_CONFIG_INFO_LENGTH 64
201
202 /* Offsets of fields from the begginning for the packet */
203 #define MST_BPDU_VER3_LEN_OFFSET 36
204 #define MST_BPDU_CONFIG_NAME_OFFSET 39
205 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73
206 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89
207 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93
208 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101
209 #define MST_BPDU_MSTI_OFFSET 102
210 /* Offsets within an MSTI */
211 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1
212 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9
213 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13
214 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14
215 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15
216
217 #define SPB_BPDU_MIN_LEN 87
218 #define SPB_BPDU_CONFIG_NAME_OFFSET 3
219 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32
220 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2
221 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16
222 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1
223 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1
224 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1
225 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1
226 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2
227 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4
228 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4
229
230
231 static void
232 stp_print_mstp_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
233 {
234 const u_char *ptr;
235 u_int16_t v3len;
236 u_int16_t len;
237 u_int16_t msti;
238 u_int offset;
239
240 ptr = (const u_char *)stp_bpdu;
241 printf(", 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 (!vflag) {
248 return;
249 }
250
251 printf("\n\tport-role %s, ",
252 tok2str(rstp_obj_port_role_values, "Unknown",
253 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
254
255 printf("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 printf("\n\tCIST regional-root-id %s, ",
260 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id));
261
262 printf("CIST port-id %04x, ", EXTRACT_16BITS(&stp_bpdu->port_id));
263
264 printf("\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 printf ("\n\tv3len %d, ", EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET));
272 printf("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 printf ("CIST int-root-pathcost %u, ",
282 EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET));
283
284 printf("\n\tCIST bridge-id %s, ",
285 stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET));
286
287 printf("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 printf("\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 printf("\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 printf("\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
320 stp_print_spb_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int offset)
321 {
322 const u_char *ptr;
323
324 /*
325 * in non-verbose mode don't print anything.
326 */
327 if (!vflag) {
328 return;
329 }
330
331 ptr = (const u_char *)stp_bpdu;
332 printf("\n\tv4len %d AUXMCID Name %s, Rev %u, \n\t\tdigest %08x%08x%08x%08x",
333 EXTRACT_16BITS (ptr + offset),
334 ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET,
335 EXTRACT_16BITS(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET),
336 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET),
337 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4),
338 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8),
339 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12));
340
341 printf("\n\tAgreement num %d, Discarded Agreement num %d, Agreement valid-"
342 "flag %d, \n\tRestricted role-flag: %d, Format id %d cap %d, "
343 "Convention id %d cap %d, \n\tEdge count %d, "
344 "Agreement digest %08x%08x%08x%08x%08x\n",
345 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>6,
346 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>4 & 0x3,
347 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>3 & 0x1,
348 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>2 & 0x1,
349 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]>>4,
350 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]&0x00ff,
351 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]>>4,
352 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]&0x00ff,
353 EXTRACT_16BITS(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET),
354 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET),
355 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+4,
356 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+8,
357 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+12,
358 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+16);
359 }
360
361 /*
362 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets.
363 */
364 void
365 stp_print(const u_char *p, u_int length)
366 {
367 const struct stp_bpdu_ *stp_bpdu;
368 u_int mstp_len;
369 u_int spb_len;
370
371 stp_bpdu = (struct stp_bpdu_*)p;
372
373 /* Minimum STP Frame size. */
374 if (length < 4)
375 goto trunc;
376
377 if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) {
378 printf("unknown STP version, length %u", length);
379 return;
380 }
381
382 printf("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
383 stp_bpdu->protocol_version));
384
385 switch (stp_bpdu->protocol_version) {
386 case STP_PROTO_REGULAR:
387 case STP_PROTO_RAPID:
388 case STP_PROTO_MSTP:
389 case STP_PROTO_SPB:
390 break;
391 default:
392 return;
393 }
394
395 printf(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
396 stp_bpdu->bpdu_type));
397
398 switch (stp_bpdu->bpdu_type) {
399 case STP_BPDU_TYPE_CONFIG:
400 if (length < sizeof(struct stp_bpdu_) - 1) {
401 goto trunc;
402 }
403 stp_print_config_bpdu(stp_bpdu, length);
404 break;
405
406 case STP_BPDU_TYPE_RSTP:
407 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
408 if (length < sizeof(struct stp_bpdu_)) {
409 goto trunc;
410 }
411 stp_print_config_bpdu(stp_bpdu, length);
412 } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP ||
413 stp_bpdu->protocol_version == STP_PROTO_SPB) {
414 if (length < STP_BPDU_MSTP_MIN_LEN) {
415 goto trunc;
416 }
417
418 if (stp_bpdu->v1_length != 0) {
419 /* FIX ME: Emit a message here ? */
420 goto trunc;
421 }
422
423 /* Validate v3 length */
424 mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET);
425 mstp_len += 2; /* length encoding itself is 2 bytes */
426 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) {
427 goto trunc;
428 }
429 stp_print_mstp_bpdu(stp_bpdu, length);
430
431 if (stp_bpdu->protocol_version == STP_PROTO_SPB)
432 {
433 /* Validate v4 length */
434 spb_len = EXTRACT_16BITS (p + MST_BPDU_VER3_LEN_OFFSET + mstp_len);
435 spb_len += 2;
436 if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) ||
437 spb_len < SPB_BPDU_MIN_LEN) {
438 goto trunc;
439 }
440 stp_print_spb_bpdu(stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len));
441 }
442 }
443 break;
444
445 case STP_BPDU_TYPE_TOPO_CHANGE:
446 /* always empty message - just break out */
447 break;
448
449 default:
450 break;
451 }
452
453 return;
454 trunc:
455 printf("[|stp %d]", length);
456 }
457
458 /*
459 * Local Variables:
460 * c-style: whitesmith
461 * c-basic-offset: 4
462 * End:
463 */
[mirror] the TCPdump network dissector