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 (at) 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 * 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 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 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 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 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
