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 (at) gnu.org> 9 */ 10 11 /* \summary: IEEE 802.1d Spanning Tree Protocol (STP) printer */ 12 13 #include <sys/cdefs.h> 14 #ifndef lint 15 __RCSID("$NetBSD: print-stp.c,v 1.10 2024/09/02 16:15:33 christos Exp $"); 16 #endif 17 18 #include <config.h> 19 20 #include "netdissect-stdinc.h" 21 22 #include <stdio.h> 23 24 #include "netdissect.h" 25 #include "extract.h" 26 27 #define RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2) 28 /* STP timers are expressed in multiples of 1/256th second */ 29 #define STP_TIME_BASE 256 30 #define STP_BPDU_MSTP_MIN_LEN 102 31 32 struct stp_bpdu_ { 33 nd_uint16_t protocol_id; 34 nd_uint8_t protocol_version; 35 nd_uint8_t bpdu_type; 36 nd_uint8_t flags; 37 nd_byte root_id[8]; 38 nd_uint32_t root_path_cost; 39 nd_byte bridge_id[8]; 40 nd_uint16_t port_id; 41 nd_uint16_t message_age; 42 nd_uint16_t max_age; 43 nd_uint16_t hello_time; 44 nd_uint16_t forward_delay; 45 nd_uint8_t v1_length; 46 }; 47 48 #define STP_PROTO_REGULAR 0x00 49 #define STP_PROTO_RAPID 0x02 50 #define STP_PROTO_MSTP 0x03 51 #define STP_PROTO_SPB 0x04 52 53 static const struct tok stp_proto_values[] = { 54 { STP_PROTO_REGULAR, "802.1d" }, 55 { STP_PROTO_RAPID, "802.1w" }, 56 { STP_PROTO_MSTP, "802.1s" }, 57 { STP_PROTO_SPB, "802.1aq" }, 58 { 0, NULL} 59 }; 60 61 #define STP_BPDU_TYPE_CONFIG 0x00 62 #define STP_BPDU_TYPE_RSTP 0x02 63 #define STP_BPDU_TYPE_TOPO_CHANGE 0x80 64 65 static const struct tok stp_bpdu_flag_values[] = { 66 { 0x01, "Topology change" }, 67 { 0x02, "Proposal" }, 68 { 0x10, "Learn" }, 69 { 0x20, "Forward" }, 70 { 0x40, "Agreement" }, 71 { 0x80, "Topology change ACK" }, 72 { 0, NULL} 73 }; 74 75 static const struct tok stp_bpdu_type_values[] = { 76 { STP_BPDU_TYPE_CONFIG, "Config" }, 77 { STP_BPDU_TYPE_RSTP, "Rapid STP" }, 78 { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" }, 79 { 0, NULL} 80 }; 81 82 static const struct tok rstp_obj_port_role_values[] = { 83 { 0x00, "Unknown" }, 84 { 0x01, "Alternate" }, 85 { 0x02, "Root" }, 86 { 0x03, "Designated" }, 87 { 0, NULL} 88 }; 89 90 static char * 91 stp_print_bridge_id(netdissect_options *ndo, const u_char *p) 92 { 93 static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")]; 94 95 snprintf(bridge_id_str, sizeof(bridge_id_str), 96 "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x", 97 GET_U_1(p), GET_U_1(p + 1), GET_U_1(p + 2), 98 GET_U_1(p + 3), GET_U_1(p + 4), GET_U_1(p + 5), 99 GET_U_1(p + 6), GET_U_1(p + 7)); 100 101 return bridge_id_str; 102 } 103 104 static void 105 stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 106 u_int length) 107 { 108 uint8_t bpdu_flags; 109 110 bpdu_flags = GET_U_1(stp_bpdu->flags); 111 ND_PRINT(", Flags [%s]", 112 bittok2str(stp_bpdu_flag_values, "none", bpdu_flags)); 113 114 ND_PRINT(", bridge-id %s.%04x, length %u", 115 stp_print_bridge_id(ndo, stp_bpdu->bridge_id), 116 GET_BE_U_2(stp_bpdu->port_id), length); 117 118 /* in non-verbose mode just print the bridge-id */ 119 if (!ndo->ndo_vflag) { 120 return; 121 } 122 123 ND_PRINT("\n\tmessage-age %.2fs, max-age %.2fs" 124 ", hello-time %.2fs, forwarding-delay %.2fs", 125 (float) GET_BE_U_2(stp_bpdu->message_age) / STP_TIME_BASE, 126 (float) GET_BE_U_2(stp_bpdu->max_age) / STP_TIME_BASE, 127 (float) GET_BE_U_2(stp_bpdu->hello_time) / STP_TIME_BASE, 128 (float) GET_BE_U_2(stp_bpdu->forward_delay) / STP_TIME_BASE); 129 130 ND_PRINT("\n\troot-id %s, root-pathcost %u", 131 stp_print_bridge_id(ndo, stp_bpdu->root_id), 132 GET_BE_U_4(stp_bpdu->root_path_cost)); 133 134 /* Port role is only valid for 802.1w */ 135 if (GET_U_1(stp_bpdu->protocol_version) == STP_PROTO_RAPID) { 136 ND_PRINT(", port-role %s", 137 tok2str(rstp_obj_port_role_values, "Unknown", 138 RSTP_EXTRACT_PORT_ROLE(bpdu_flags))); 139 } 140 } 141 142 /* 143 * MSTP packet format 144 * Ref. IEEE 802.1Q 2003 Ed. Section 14 145 * 146 * MSTP BPDU 147 * 148 * 2 - bytes Protocol Id 149 * 1 - byte Protocol Ver. 150 * 1 - byte BPDU type 151 * 1 - byte Flags 152 * 8 - bytes CIST Root Identifier 153 * 4 - bytes CIST External Path Cost 154 * 8 - bytes CIST Regional Root Identifier 155 * 2 - bytes CIST Port Identifier 156 * 2 - bytes Message Age 157 * 2 - bytes Max age 158 * 2 - bytes Hello Time 159 * 2 - bytes Forward delay 160 * 1 - byte Version 1 length. Must be 0 161 * 2 - bytes Version 3 length 162 * 1 - byte Config Identifier 163 * 32 - bytes Config Name 164 * 2 - bytes Revision level 165 * 16 - bytes Config Digest [MD5] 166 * 4 - bytes CIST Internal Root Path Cost 167 * 8 - bytes CIST Bridge Identifier 168 * 1 - byte CIST Remaining Hops 169 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes] 170 * 171 * 172 * SPB BPDU 173 * Ref. IEEE 802.1aq. Section 14 174 * 175 * 2 - bytes Version 4 length 176 * 1 - byte Aux Config Identifier 177 * 32 - bytes Aux Config Name 178 * 2 - bytes Aux Revision level 179 * 16 - bytes Aux Config Digest [MD5] 180 * 1 - byte (1 - 2) Agreement Number 181 * (3 - 4) Discarded Agreement Number 182 * (5) Agreement Valid Flag 183 * (6) Restricted Role Flag 184 * (7 - 8) Unused sent zero 185 * 1 - byte Unused 186 * 1 - byte (1 - 4) Agreement Digest Format Identifier 187 * (5 - 8) Agreement Digest Format Capabilities 188 * 1 - byte (1 - 4) Agreement Digest Convention Identifier 189 * (5 - 8) Agreement Digest Convention Capabilities 190 * 2 - bytes Agreement Digest Edge Count 191 * 8 - byte Reserved Set 192 * 20 - bytes Computed Topology Digest 193 * 194 * 195 * MSTI Payload 196 * 197 * 1 - byte MSTI flag 198 * 8 - bytes MSTI Regional Root Identifier 199 * 4 - bytes MSTI Regional Path Cost 200 * 1 - byte MSTI Bridge Priority 201 * 1 - byte MSTI Port Priority 202 * 1 - byte MSTI Remaining Hops 203 * 204 */ 205 206 #define MST_BPDU_MSTI_LENGTH 16 207 #define MST_BPDU_CONFIG_INFO_LENGTH 64 208 209 /* Offsets of fields from the beginning for the packet */ 210 #define MST_BPDU_VER3_LEN_OFFSET 36 211 #define MST_BPDU_CONFIG_NAME_OFFSET 39 212 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73 213 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89 214 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93 215 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101 216 #define MST_BPDU_MSTI_OFFSET 102 217 /* Offsets within an MSTI */ 218 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1 219 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9 220 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13 221 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14 222 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15 223 224 #define SPB_BPDU_MIN_LEN 87 225 #define SPB_BPDU_CONFIG_NAME_OFFSET 3 226 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32 227 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2 228 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16 229 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1 230 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1 231 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1 232 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1 233 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2 234 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4 235 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4 236 237 static void 238 stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 239 u_int length) 240 { 241 const u_char *ptr; 242 uint8_t bpdu_flags; 243 uint16_t v3len; 244 uint16_t len; 245 uint16_t msti; 246 u_int offset; 247 248 ptr = (const u_char *)stp_bpdu; 249 bpdu_flags = GET_U_1(stp_bpdu->flags); 250 ND_PRINT(", CIST Flags [%s], length %u", 251 bittok2str(stp_bpdu_flag_values, "none", bpdu_flags), length); 252 253 /* 254 * in non-verbose mode just print the flags. 255 */ 256 if (!ndo->ndo_vflag) { 257 return; 258 } 259 260 ND_PRINT("\n\tport-role %s, ", 261 tok2str(rstp_obj_port_role_values, "Unknown", 262 RSTP_EXTRACT_PORT_ROLE(bpdu_flags))); 263 264 ND_PRINT("CIST root-id %s, CIST ext-pathcost %u", 265 stp_print_bridge_id(ndo, stp_bpdu->root_id), 266 GET_BE_U_4(stp_bpdu->root_path_cost)); 267 268 ND_PRINT("\n\tCIST regional-root-id %s, ", 269 stp_print_bridge_id(ndo, stp_bpdu->bridge_id)); 270 271 ND_PRINT("CIST port-id %04x,", GET_BE_U_2(stp_bpdu->port_id)); 272 273 ND_PRINT("\n\tmessage-age %.2fs, max-age %.2fs" 274 ", hello-time %.2fs, forwarding-delay %.2fs", 275 (float) GET_BE_U_2(stp_bpdu->message_age) / STP_TIME_BASE, 276 (float) GET_BE_U_2(stp_bpdu->max_age) / STP_TIME_BASE, 277 (float) GET_BE_U_2(stp_bpdu->hello_time) / STP_TIME_BASE, 278 (float) GET_BE_U_2(stp_bpdu->forward_delay) / STP_TIME_BASE); 279 280 ND_PRINT("\n\tv3len %u, ", GET_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET)); 281 ND_PRINT("MCID Name "); 282 nd_printjnp(ndo, ptr + MST_BPDU_CONFIG_NAME_OFFSET, 32); 283 ND_PRINT(", rev %u," 284 "\n\t\tdigest %08x%08x%08x%08x, ", 285 GET_BE_U_2(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32), 286 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET), 287 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4), 288 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8), 289 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12)); 290 291 ND_PRINT("CIST int-root-pathcost %u,", 292 GET_BE_U_4(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET)); 293 294 ND_PRINT("\n\tCIST bridge-id %s, ", 295 stp_print_bridge_id(ndo, ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET)); 296 297 ND_PRINT("CIST remaining-hops %u", 298 GET_U_1(ptr + MST_BPDU_CIST_REMAIN_HOPS_OFFSET)); 299 300 /* Dump all MSTI's */ 301 v3len = GET_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET); 302 if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) { 303 len = v3len - MST_BPDU_CONFIG_INFO_LENGTH; 304 offset = MST_BPDU_MSTI_OFFSET; 305 while (len >= MST_BPDU_MSTI_LENGTH) { 306 msti = GET_BE_U_2(ptr + offset + MST_BPDU_MSTI_ROOT_PRIO_OFFSET); 307 msti = msti & 0x0FFF; 308 309 ND_PRINT("\n\tMSTI %u, Flags [%s], port-role %s", 310 msti, 311 bittok2str(stp_bpdu_flag_values, "none", GET_U_1(ptr + offset)), 312 tok2str(rstp_obj_port_role_values, "Unknown", 313 RSTP_EXTRACT_PORT_ROLE(GET_U_1(ptr + offset)))); 314 ND_PRINT("\n\t\tMSTI regional-root-id %s, pathcost %u", 315 stp_print_bridge_id(ndo, ptr + offset + 316 MST_BPDU_MSTI_ROOT_PRIO_OFFSET), 317 GET_BE_U_4(ptr + offset + MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET)); 318 ND_PRINT("\n\t\tMSTI bridge-prio %u, port-prio %u, hops %u", 319 GET_U_1(ptr + offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET) >> 4, 320 GET_U_1(ptr + offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET) >> 4, 321 GET_U_1(ptr + offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET)); 322 323 len -= MST_BPDU_MSTI_LENGTH; 324 offset += MST_BPDU_MSTI_LENGTH; 325 } 326 } 327 } 328 329 static void 330 stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 331 u_int offset) 332 { 333 const u_char *ptr; 334 335 /* 336 * in non-verbose mode don't print anything. 337 */ 338 if (!ndo->ndo_vflag) { 339 return; 340 } 341 342 ptr = (const u_char *)stp_bpdu; 343 344 ND_PRINT("\n\tv4len %u, ", GET_BE_U_2(ptr + offset)); 345 ND_PRINT("AUXMCID Name "); 346 nd_printjnp(ndo, ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET, 32); 347 ND_PRINT(", Rev %u,\n\t\tdigest %08x%08x%08x%08x", 348 GET_BE_U_2(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET), 349 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET), 350 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4), 351 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8), 352 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12)); 353 354 ND_PRINT("\n\tAgreement num %u, Discarded Agreement num %u, Agreement valid-" 355 "flag %u,\n\tRestricted role-flag: %u, Format id %u cap %u, " 356 "Convention id %u cap %u,\n\tEdge count %u, " 357 "Agreement digest %08x%08x%08x%08x%08x", 358 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>6, 359 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>4 & 0x3, 360 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>3 & 0x1, 361 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>2 & 0x1, 362 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)>>4, 363 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)&0x00ff, 364 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)>>4, 365 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)&0x00ff, 366 GET_BE_U_2(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET), 367 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET), 368 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 4), 369 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 8), 370 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 12), 371 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 16)); 372 } 373 374 /* 375 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets. 376 */ 377 void 378 stp_print(netdissect_options *ndo, const u_char *p, u_int length) 379 { 380 const struct stp_bpdu_ *stp_bpdu; 381 u_int protocol_version; 382 u_int bpdu_type; 383 u_int mstp_len; 384 u_int spb_len; 385 386 ndo->ndo_protocol = "stp"; 387 stp_bpdu = (const struct stp_bpdu_*)p; 388 389 /* Minimum STP Frame size. */ 390 if (length < 4) 391 goto invalid; 392 393 if (GET_BE_U_2(stp_bpdu->protocol_id)) { 394 ND_PRINT("unknown STP version, length %u", length); 395 return; 396 } 397 398 protocol_version = GET_U_1(stp_bpdu->protocol_version); 399 ND_PRINT("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)", 400 protocol_version)); 401 402 switch (protocol_version) { 403 case STP_PROTO_REGULAR: 404 case STP_PROTO_RAPID: 405 case STP_PROTO_MSTP: 406 case STP_PROTO_SPB: 407 break; 408 default: 409 return; 410 } 411 412 bpdu_type = GET_U_1(stp_bpdu->bpdu_type); 413 ND_PRINT(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)", 414 bpdu_type)); 415 416 switch (bpdu_type) { 417 case STP_BPDU_TYPE_CONFIG: 418 if (length < sizeof(struct stp_bpdu_) - 1) { 419 goto invalid; 420 } 421 stp_print_config_bpdu(ndo, stp_bpdu, length); 422 break; 423 424 case STP_BPDU_TYPE_RSTP: 425 if (protocol_version == STP_PROTO_RAPID) { 426 if (length < sizeof(struct stp_bpdu_)) { 427 goto invalid; 428 } 429 stp_print_config_bpdu(ndo, stp_bpdu, length); 430 } else if (protocol_version == STP_PROTO_MSTP || 431 protocol_version == STP_PROTO_SPB) { 432 if (length < STP_BPDU_MSTP_MIN_LEN) { 433 goto invalid; 434 } 435 436 if (GET_U_1(stp_bpdu->v1_length) != 0) { 437 /* FIX ME: Emit a message here ? */ 438 goto invalid; 439 } 440 441 /* Validate v3 length */ 442 mstp_len = GET_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET); 443 mstp_len += 2; /* length encoding itself is 2 bytes */ 444 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) { 445 goto invalid; 446 } 447 stp_print_mstp_bpdu(ndo, stp_bpdu, length); 448 449 if (protocol_version == STP_PROTO_SPB) { 450 /* Validate v4 length */ 451 spb_len = GET_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET + mstp_len); 452 spb_len += 2; 453 if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) || 454 spb_len < SPB_BPDU_MIN_LEN) { 455 goto invalid; 456 } 457 stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len)); 458 } 459 } 460 break; 461 462 case STP_BPDU_TYPE_TOPO_CHANGE: 463 /* always empty message - just break out */ 464 break; 465 466 default: 467 break; 468 } 469 return; 470 471 invalid: 472 nd_print_invalid(ndo); 473 } 474
Indexes created Sun Aug 16 00:25:19 UTC 2026