print-stp.c revision 1.9
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 1.9 2023/08/17 20:19:40 christos Exp $"); 16 #endif 17 18 #ifdef HAVE_CONFIG_H 19 #include <config.h> 20 #endif 21 22 #include "netdissect-stdinc.h" 23 24 #include <stdio.h> 25 26 #include "netdissect.h" 27 #include "extract.h" 28 29 #define RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2) 30 /* STP timers are expressed in multiples of 1/256th second */ 31 #define STP_TIME_BASE 256 32 #define STP_BPDU_MSTP_MIN_LEN 102 33 34 struct stp_bpdu_ { 35 nd_uint16_t protocol_id; 36 nd_uint8_t protocol_version; 37 nd_uint8_t bpdu_type; 38 nd_uint8_t flags; 39 nd_byte root_id[8]; 40 nd_uint32_t root_path_cost; 41 nd_byte bridge_id[8]; 42 nd_uint16_t port_id; 43 nd_uint16_t message_age; 44 nd_uint16_t max_age; 45 nd_uint16_t hello_time; 46 nd_uint16_t forward_delay; 47 nd_uint8_t v1_length; 48 }; 49 50 #define STP_PROTO_REGULAR 0x00 51 #define STP_PROTO_RAPID 0x02 52 #define STP_PROTO_MSTP 0x03 53 #define STP_PROTO_SPB 0x04 54 55 static const struct tok stp_proto_values[] = { 56 { STP_PROTO_REGULAR, "802.1d" }, 57 { STP_PROTO_RAPID, "802.1w" }, 58 { STP_PROTO_MSTP, "802.1s" }, 59 { STP_PROTO_SPB, "802.1aq" }, 60 { 0, NULL} 61 }; 62 63 #define STP_BPDU_TYPE_CONFIG 0x00 64 #define STP_BPDU_TYPE_RSTP 0x02 65 #define STP_BPDU_TYPE_TOPO_CHANGE 0x80 66 67 static const struct tok stp_bpdu_flag_values[] = { 68 { 0x01, "Topology change" }, 69 { 0x02, "Proposal" }, 70 { 0x10, "Learn" }, 71 { 0x20, "Forward" }, 72 { 0x40, "Agreement" }, 73 { 0x80, "Topology change ACK" }, 74 { 0, NULL} 75 }; 76 77 static const struct tok stp_bpdu_type_values[] = { 78 { STP_BPDU_TYPE_CONFIG, "Config" }, 79 { STP_BPDU_TYPE_RSTP, "Rapid STP" }, 80 { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" }, 81 { 0, NULL} 82 }; 83 84 static const struct tok rstp_obj_port_role_values[] = { 85 { 0x00, "Unknown" }, 86 { 0x01, "Alternate" }, 87 { 0x02, "Root" }, 88 { 0x03, "Designated" }, 89 { 0, NULL} 90 }; 91 92 static char * 93 stp_print_bridge_id(netdissect_options *ndo, const u_char *p) 94 { 95 static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")]; 96 97 snprintf(bridge_id_str, sizeof(bridge_id_str), 98 "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x", 99 GET_U_1(p), GET_U_1(p + 1), GET_U_1(p + 2), 100 GET_U_1(p + 3), GET_U_1(p + 4), GET_U_1(p + 5), 101 GET_U_1(p + 6), GET_U_1(p + 7)); 102 103 return bridge_id_str; 104 } 105 106 static void 107 stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 108 u_int length) 109 { 110 uint8_t bpdu_flags; 111 112 bpdu_flags = GET_U_1(stp_bpdu->flags); 113 ND_PRINT(", Flags [%s]", 114 bittok2str(stp_bpdu_flag_values, "none", bpdu_flags)); 115 116 ND_PRINT(", bridge-id %s.%04x, length %u", 117 stp_print_bridge_id(ndo, stp_bpdu->bridge_id), 118 GET_BE_U_2(stp_bpdu->port_id), length); 119 120 /* in non-verbose mode just print the bridge-id */ 121 if (!ndo->ndo_vflag) { 122 return; 123 } 124 125 ND_PRINT("\n\tmessage-age %.2fs, max-age %.2fs" 126 ", hello-time %.2fs, forwarding-delay %.2fs", 127 (float) GET_BE_U_2(stp_bpdu->message_age) / STP_TIME_BASE, 128 (float) GET_BE_U_2(stp_bpdu->max_age) / STP_TIME_BASE, 129 (float) GET_BE_U_2(stp_bpdu->hello_time) / STP_TIME_BASE, 130 (float) GET_BE_U_2(stp_bpdu->forward_delay) / STP_TIME_BASE); 131 132 ND_PRINT("\n\troot-id %s, root-pathcost %u", 133 stp_print_bridge_id(ndo, stp_bpdu->root_id), 134 GET_BE_U_4(stp_bpdu->root_path_cost)); 135 136 /* Port role is only valid for 802.1w */ 137 if (GET_U_1(stp_bpdu->protocol_version) == STP_PROTO_RAPID) { 138 ND_PRINT(", port-role %s", 139 tok2str(rstp_obj_port_role_values, "Unknown", 140 RSTP_EXTRACT_PORT_ROLE(bpdu_flags))); 141 } 142 } 143 144 /* 145 * MSTP packet format 146 * Ref. IEEE 802.1Q 2003 Ed. Section 14 147 * 148 * MSTP BPDU 149 * 150 * 2 - bytes Protocol Id 151 * 1 - byte Protocol Ver. 152 * 1 - byte BPDU type 153 * 1 - byte Flags 154 * 8 - bytes CIST Root Identifier 155 * 4 - bytes CIST External Path Cost 156 * 8 - bytes CIST Regional Root Identifier 157 * 2 - bytes CIST Port Identifier 158 * 2 - bytes Message Age 159 * 2 - bytes Max age 160 * 2 - bytes Hello Time 161 * 2 - bytes Forward delay 162 * 1 - byte Version 1 length. Must be 0 163 * 2 - bytes Version 3 length 164 * 1 - byte Config Identifier 165 * 32 - bytes Config Name 166 * 2 - bytes Revision level 167 * 16 - bytes Config Digest [MD5] 168 * 4 - bytes CIST Internal Root Path Cost 169 * 8 - bytes CIST Bridge Identifier 170 * 1 - byte CIST Remaining Hops 171 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes] 172 * 173 * 174 * SPB BPDU 175 * Ref. IEEE 802.1aq. Section 14 176 * 177 * 2 - bytes Version 4 length 178 * 1 - byte Aux Config Identifier 179 * 32 - bytes Aux Config Name 180 * 2 - bytes Aux Revision level 181 * 16 - bytes Aux Config Digest [MD5] 182 * 1 - byte (1 - 2) Agreement Number 183 * (3 - 4) Discarded Agreement Number 184 * (5) Agreement Valid Flag 185 * (6) Restricted Role Flag 186 * (7 - 8) Unused sent zero 187 * 1 - byte Unused 188 * 1 - byte (1 - 4) Agreement Digest Format Identifier 189 * (5 - 8) Agreement Digest Format Capabilities 190 * 1 - byte (1 - 4) Agreement Digest Convention Identifier 191 * (5 - 8) Agreement Digest Convention Capabilities 192 * 2 - bytes Agreement Digest Edge Count 193 * 8 - byte Reserved Set 194 * 20 - bytes Computed Topology Digest 195 * 196 * 197 * MSTI Payload 198 * 199 * 1 - byte MSTI flag 200 * 8 - bytes MSTI Regional Root Identifier 201 * 4 - bytes MSTI Regional Path Cost 202 * 1 - byte MSTI Bridge Priority 203 * 1 - byte MSTI Port Priority 204 * 1 - byte MSTI Remaining Hops 205 * 206 */ 207 208 #define MST_BPDU_MSTI_LENGTH 16 209 #define MST_BPDU_CONFIG_INFO_LENGTH 64 210 211 /* Offsets of fields from the beginning for the packet */ 212 #define MST_BPDU_VER3_LEN_OFFSET 36 213 #define MST_BPDU_CONFIG_NAME_OFFSET 39 214 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73 215 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89 216 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93 217 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101 218 #define MST_BPDU_MSTI_OFFSET 102 219 /* Offsets within an MSTI */ 220 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1 221 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9 222 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13 223 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14 224 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15 225 226 #define SPB_BPDU_MIN_LEN 87 227 #define SPB_BPDU_CONFIG_NAME_OFFSET 3 228 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32 229 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2 230 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16 231 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1 232 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1 233 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1 234 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1 235 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2 236 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4 237 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4 238 239 static void 240 stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 241 u_int length) 242 { 243 const u_char *ptr; 244 uint8_t bpdu_flags; 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 bpdu_flags = GET_U_1(stp_bpdu->flags); 252 ND_PRINT(", CIST Flags [%s], length %u", 253 bittok2str(stp_bpdu_flag_values, "none", bpdu_flags), length); 254 255 /* 256 * in non-verbose mode just print the flags. 257 */ 258 if (!ndo->ndo_vflag) { 259 return; 260 } 261 262 ND_PRINT("\n\tport-role %s, ", 263 tok2str(rstp_obj_port_role_values, "Unknown", 264 RSTP_EXTRACT_PORT_ROLE(bpdu_flags))); 265 266 ND_PRINT("CIST root-id %s, CIST ext-pathcost %u", 267 stp_print_bridge_id(ndo, stp_bpdu->root_id), 268 GET_BE_U_4(stp_bpdu->root_path_cost)); 269 270 ND_PRINT("\n\tCIST regional-root-id %s, ", 271 stp_print_bridge_id(ndo, stp_bpdu->bridge_id)); 272 273 ND_PRINT("CIST port-id %04x,", GET_BE_U_2(stp_bpdu->port_id)); 274 275 ND_PRINT("\n\tmessage-age %.2fs, max-age %.2fs" 276 ", hello-time %.2fs, forwarding-delay %.2fs", 277 (float) GET_BE_U_2(stp_bpdu->message_age) / STP_TIME_BASE, 278 (float) GET_BE_U_2(stp_bpdu->max_age) / STP_TIME_BASE, 279 (float) GET_BE_U_2(stp_bpdu->hello_time) / STP_TIME_BASE, 280 (float) GET_BE_U_2(stp_bpdu->forward_delay) / STP_TIME_BASE); 281 282 ND_PRINT("\n\tv3len %u, ", GET_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET)); 283 ND_PRINT("MCID Name "); 284 nd_printjnp(ndo, ptr + MST_BPDU_CONFIG_NAME_OFFSET, 32); 285 ND_PRINT(", rev %u," 286 "\n\t\tdigest %08x%08x%08x%08x, ", 287 GET_BE_U_2(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32), 288 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET), 289 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4), 290 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8), 291 GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12)); 292 293 ND_PRINT("CIST int-root-pathcost %u,", 294 GET_BE_U_4(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET)); 295 296 ND_PRINT("\n\tCIST bridge-id %s, ", 297 stp_print_bridge_id(ndo, ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET)); 298 299 ND_PRINT("CIST remaining-hops %u", 300 GET_U_1(ptr + MST_BPDU_CIST_REMAIN_HOPS_OFFSET)); 301 302 /* Dump all MSTI's */ 303 v3len = GET_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET); 304 if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) { 305 len = v3len - MST_BPDU_CONFIG_INFO_LENGTH; 306 offset = MST_BPDU_MSTI_OFFSET; 307 while (len >= MST_BPDU_MSTI_LENGTH) { 308 msti = GET_BE_U_2(ptr + offset + MST_BPDU_MSTI_ROOT_PRIO_OFFSET); 309 msti = msti & 0x0FFF; 310 311 ND_PRINT("\n\tMSTI %u, Flags [%s], port-role %s", 312 msti, 313 bittok2str(stp_bpdu_flag_values, "none", GET_U_1(ptr + offset)), 314 tok2str(rstp_obj_port_role_values, "Unknown", 315 RSTP_EXTRACT_PORT_ROLE(GET_U_1(ptr + offset)))); 316 ND_PRINT("\n\t\tMSTI regional-root-id %s, pathcost %u", 317 stp_print_bridge_id(ndo, ptr + offset + 318 MST_BPDU_MSTI_ROOT_PRIO_OFFSET), 319 GET_BE_U_4(ptr + offset + MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET)); 320 ND_PRINT("\n\t\tMSTI bridge-prio %u, port-prio %u, hops %u", 321 GET_U_1(ptr + offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET) >> 4, 322 GET_U_1(ptr + offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET) >> 4, 323 GET_U_1(ptr + offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET)); 324 325 len -= MST_BPDU_MSTI_LENGTH; 326 offset += MST_BPDU_MSTI_LENGTH; 327 } 328 } 329 } 330 331 static void 332 stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 333 u_int offset) 334 { 335 const u_char *ptr; 336 337 /* 338 * in non-verbose mode don't print anything. 339 */ 340 if (!ndo->ndo_vflag) { 341 return; 342 } 343 344 ptr = (const u_char *)stp_bpdu; 345 346 ND_PRINT("\n\tv4len %u, ", GET_BE_U_2(ptr + offset)); 347 ND_PRINT("AUXMCID Name "); 348 nd_printjnp(ndo, ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET, 32); 349 ND_PRINT(", Rev %u,\n\t\tdigest %08x%08x%08x%08x", 350 GET_BE_U_2(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET), 351 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET), 352 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4), 353 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8), 354 GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12)); 355 356 ND_PRINT("\n\tAgreement num %u, Discarded Agreement num %u, Agreement valid-" 357 "flag %u,\n\tRestricted role-flag: %u, Format id %u cap %u, " 358 "Convention id %u cap %u,\n\tEdge count %u, " 359 "Agreement digest %08x%08x%08x%08x%08x", 360 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>6, 361 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>4 & 0x3, 362 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>3 & 0x1, 363 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>2 & 0x1, 364 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)>>4, 365 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)&0x00ff, 366 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)>>4, 367 GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)&0x00ff, 368 GET_BE_U_2(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET), 369 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET), 370 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 4), 371 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 8), 372 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 12), 373 GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 16)); 374 } 375 376 /* 377 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets. 378 */ 379 void 380 stp_print(netdissect_options *ndo, const u_char *p, u_int length) 381 { 382 const struct stp_bpdu_ *stp_bpdu; 383 u_int protocol_version; 384 u_int bpdu_type; 385 u_int mstp_len; 386 u_int spb_len; 387 388 ndo->ndo_protocol = "stp"; 389 stp_bpdu = (const struct stp_bpdu_*)p; 390 391 /* Minimum STP Frame size. */ 392 if (length < 4) 393 goto invalid; 394 395 if (GET_BE_U_2(stp_bpdu->protocol_id)) { 396 ND_PRINT("unknown STP version, length %u", length); 397 return; 398 } 399 400 protocol_version = GET_U_1(stp_bpdu->protocol_version); 401 ND_PRINT("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)", 402 protocol_version)); 403 404 switch (protocol_version) { 405 case STP_PROTO_REGULAR: 406 case STP_PROTO_RAPID: 407 case STP_PROTO_MSTP: 408 case STP_PROTO_SPB: 409 break; 410 default: 411 return; 412 } 413 414 bpdu_type = GET_U_1(stp_bpdu->bpdu_type); 415 ND_PRINT(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)", 416 bpdu_type)); 417 418 switch (bpdu_type) { 419 case STP_BPDU_TYPE_CONFIG: 420 if (length < sizeof(struct stp_bpdu_) - 1) { 421 goto invalid; 422 } 423 stp_print_config_bpdu(ndo, stp_bpdu, length); 424 break; 425 426 case STP_BPDU_TYPE_RSTP: 427 if (protocol_version == STP_PROTO_RAPID) { 428 if (length < sizeof(struct stp_bpdu_)) { 429 goto invalid; 430 } 431 stp_print_config_bpdu(ndo, stp_bpdu, length); 432 } else if (protocol_version == STP_PROTO_MSTP || 433 protocol_version == STP_PROTO_SPB) { 434 if (length < STP_BPDU_MSTP_MIN_LEN) { 435 goto invalid; 436 } 437 438 if (GET_U_1(stp_bpdu->v1_length) != 0) { 439 /* FIX ME: Emit a message here ? */ 440 goto invalid; 441 } 442 443 /* Validate v3 length */ 444 mstp_len = GET_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET); 445 mstp_len += 2; /* length encoding itself is 2 bytes */ 446 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) { 447 goto invalid; 448 } 449 stp_print_mstp_bpdu(ndo, stp_bpdu, length); 450 451 if (protocol_version == STP_PROTO_SPB) 452 { 453 /* Validate v4 length */ 454 spb_len = GET_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET + mstp_len); 455 spb_len += 2; 456 if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) || 457 spb_len < SPB_BPDU_MIN_LEN) { 458 goto invalid; 459 } 460 stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len)); 461 } 462 } 463 break; 464 465 case STP_BPDU_TYPE_TOPO_CHANGE: 466 /* always empty message - just break out */ 467 break; 468 469 default: 470 break; 471 } 472 return; 473 474 invalid: 475 nd_print_invalid(ndo); 476 } 477
Indexes created Sat Aug 15 00:25:12 UTC 2026