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 #ifdef HAVE_CONFIG_H 14 #include "config.h" 15 #endif 16 17 #include <netdissect-stdinc.h> 18 19 #include <stdio.h> 20 21 #include "netdissect.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 #define ND_TCHECK_BRIDGE_ID(p) ND_TCHECK2(*(p), 8) 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 int 102 stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 103 u_int length) 104 { 105 ND_TCHECK(stp_bpdu->flags); 106 ND_PRINT((ndo, ", Flags [%s]", 107 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags))); 108 109 ND_TCHECK(stp_bpdu->port_id); 110 ND_PRINT((ndo, ", bridge-id %s.%04x, length %u", 111 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id), 112 EXTRACT_16BITS(&stp_bpdu->port_id), length)); 113 114 /* in non-verbose mode just print the bridge-id */ 115 if (!ndo->ndo_vflag) { 116 return 1; 117 } 118 119 ND_TCHECK(stp_bpdu->forward_delay); 120 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs" 121 ", hello-time %.2fs, forwarding-delay %.2fs", 122 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE, 123 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE, 124 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE, 125 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE)); 126 127 ND_PRINT((ndo, "\n\troot-id %s, root-pathcost %u", 128 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id), 129 EXTRACT_32BITS(&stp_bpdu->root_path_cost))); 130 131 /* Port role is only valid for 802.1w */ 132 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) { 133 ND_PRINT((ndo, ", port-role %s", 134 tok2str(rstp_obj_port_role_values, "Unknown", 135 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)))); 136 } 137 return 1; 138 139 trunc: 140 return 0; 141 } 142 143 /* 144 * MSTP packet format 145 * Ref. IEEE 802.1Q 2003 Ed. Section 14 146 * 147 * MSTP BPDU 148 * 149 * 2 - bytes Protocol Id 150 * 1 - byte Protocol Ver. 151 * 1 - byte BPDU tye 152 * 1 - byte Flags 153 * 8 - bytes CIST Root Identifier 154 * 4 - bytes CIST External Path Cost 155 * 8 - bytes CIST Regional Root Identifier 156 * 2 - bytes CIST Port Identifier 157 * 2 - bytes Message Age 158 * 2 - bytes Max age 159 * 2 - bytes Hello Time 160 * 2 - bytes Forward delay 161 * 1 - byte Version 1 length. Must be 0 162 * 2 - bytes Version 3 length 163 * 1 - byte Config Identifier 164 * 32 - bytes Config Name 165 * 2 - bytes Revision level 166 * 16 - bytes Config Digest [MD5] 167 * 4 - bytes CIST Internal Root Path Cost 168 * 8 - bytes CIST Bridge Identifier 169 * 1 - byte CIST Remaining Hops 170 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes] 171 * 172 * 173 * SPB BPDU 174 * Ref. IEEE 802.1aq. Section 14 175 * 176 * 2 - bytes Version 4 length 177 * 1 - byte Aux Config Identifier 178 * 32 - bytes Aux Config Name 179 * 2 - bytes Aux Revision level 180 * 16 - bytes Aux Config Digest [MD5] 181 * 1 - byte (1 - 2) Agreement Number 182 * (3 - 4) Discarded Agreement Number 183 * (5) Agreement Valid Flag 184 * (6) Restricted Role Flag 185 * (7 - 8) Unused sent zero 186 * 1 - byte Unused 187 * 1 - byte (1 - 4) Agreement Digest Format Identifier 188 * (5 - 8) Agreement Digest Format Capabilities 189 * 1 - byte (1 - 4) Agreement Digest Convention Identifier 190 * (5 - 8) Agreement Digest Convention Capabilities 191 * 2 - bytes Agreement Digest Edge Count 192 * 8 - byte Reserved Set 193 * 20 - bytes Computed Topology Digest 194 * 195 * 196 * MSTI Payload 197 * 198 * 1 - byte MSTI flag 199 * 8 - bytes MSTI Regional Root Identifier 200 * 4 - bytes MSTI Regional Path Cost 201 * 1 - byte MSTI Bridge Priority 202 * 1 - byte MSTI Port Priority 203 * 1 - byte MSTI Remaining Hops 204 * 205 */ 206 207 #define MST_BPDU_MSTI_LENGTH 16 208 #define MST_BPDU_CONFIG_INFO_LENGTH 64 209 210 /* Offsets of fields from the begginning for the packet */ 211 #define MST_BPDU_VER3_LEN_OFFSET 36 212 #define MST_BPDU_CONFIG_NAME_OFFSET 39 213 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73 214 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89 215 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93 216 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101 217 #define MST_BPDU_MSTI_OFFSET 102 218 /* Offsets within an MSTI */ 219 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1 220 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9 221 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13 222 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14 223 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15 224 225 #define SPB_BPDU_MIN_LEN 87 226 #define SPB_BPDU_CONFIG_NAME_OFFSET 3 227 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32 228 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2 229 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16 230 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1 231 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1 232 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1 233 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1 234 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2 235 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4 236 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4 237 238 static int 239 stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 240 u_int length) 241 { 242 const u_char *ptr; 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 ND_PRINT((ndo, ", CIST Flags [%s], length %u", 250 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags), length)); 251 252 /* 253 * in non-verbose mode just print the flags. 254 */ 255 if (!ndo->ndo_vflag) { 256 return 1; 257 } 258 259 ND_TCHECK(stp_bpdu->flags); 260 ND_PRINT((ndo, "\n\tport-role %s, ", 261 tok2str(rstp_obj_port_role_values, "Unknown", 262 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)))); 263 264 ND_TCHECK(stp_bpdu->root_path_cost); 265 ND_PRINT((ndo, "CIST root-id %s, CIST ext-pathcost %u", 266 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id), 267 EXTRACT_32BITS(&stp_bpdu->root_path_cost))); 268 269 ND_TCHECK(stp_bpdu->bridge_id); 270 ND_PRINT((ndo, "\n\tCIST regional-root-id %s, ", 271 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id))); 272 273 ND_TCHECK(stp_bpdu->port_id); 274 ND_PRINT((ndo, "CIST port-id %04x,", EXTRACT_16BITS(&stp_bpdu->port_id))); 275 276 ND_TCHECK(stp_bpdu->forward_delay); 277 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs" 278 ", hello-time %.2fs, forwarding-delay %.2fs", 279 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE, 280 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE, 281 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE, 282 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE)); 283 284 ND_TCHECK_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET); 285 ND_PRINT((ndo, "\n\tv3len %d, ", EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET))); 286 ND_TCHECK_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12); 287 ND_PRINT((ndo, "MCID Name ")); 288 if (fn_printzp(ndo, ptr + MST_BPDU_CONFIG_NAME_OFFSET, 32, ndo->ndo_snapend)) 289 goto trunc; 290 ND_PRINT((ndo, ", rev %u," 291 "\n\t\tdigest %08x%08x%08x%08x, ", 292 EXTRACT_16BITS(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32), 293 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET), 294 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4), 295 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8), 296 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12))); 297 298 ND_TCHECK_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET); 299 ND_PRINT((ndo, "CIST int-root-pathcost %u,", 300 EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET))); 301 302 ND_TCHECK_BRIDGE_ID(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET); 303 ND_PRINT((ndo, "\n\tCIST bridge-id %s, ", 304 stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET))); 305 306 ND_TCHECK(ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]); 307 ND_PRINT((ndo, "CIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET])); 308 309 /* Dump all MSTI's */ 310 ND_TCHECK_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET); 311 v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET); 312 if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) { 313 len = v3len - MST_BPDU_CONFIG_INFO_LENGTH; 314 offset = MST_BPDU_MSTI_OFFSET; 315 while (len >= MST_BPDU_MSTI_LENGTH) { 316 ND_TCHECK2(*(ptr + offset), MST_BPDU_MSTI_LENGTH); 317 318 msti = EXTRACT_16BITS(ptr + offset + 319 MST_BPDU_MSTI_ROOT_PRIO_OFFSET); 320 msti = msti & 0x0FFF; 321 322 ND_PRINT((ndo, "\n\tMSTI %d, Flags [%s], port-role %s", 323 msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]), 324 tok2str(rstp_obj_port_role_values, "Unknown", 325 RSTP_EXTRACT_PORT_ROLE(ptr[offset])))); 326 ND_PRINT((ndo, "\n\t\tMSTI regional-root-id %s, pathcost %u", 327 stp_print_bridge_id(ptr + offset + 328 MST_BPDU_MSTI_ROOT_PRIO_OFFSET), 329 EXTRACT_32BITS(ptr + offset + 330 MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET))); 331 ND_PRINT((ndo, "\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d", 332 ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET] >> 4, 333 ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET] >> 4, 334 ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET])); 335 336 len -= MST_BPDU_MSTI_LENGTH; 337 offset += MST_BPDU_MSTI_LENGTH; 338 } 339 } 340 return 1; 341 342 trunc: 343 return 0; 344 } 345 346 static int 347 stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 348 u_int offset) 349 { 350 const u_char *ptr; 351 352 /* 353 * in non-verbose mode don't print anything. 354 */ 355 if (!ndo->ndo_vflag) { 356 return 1; 357 } 358 359 ptr = (const u_char *)stp_bpdu; 360 ND_TCHECK_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 16); 361 362 ND_PRINT((ndo, "\n\tv4len %d, ", EXTRACT_16BITS (ptr + offset))); 363 ND_PRINT((ndo, "AUXMCID Name ")); 364 if (fn_printzp(ndo, ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET, 32, 365 ndo->ndo_snapend)) 366 goto trunc; 367 ND_PRINT((ndo, ", Rev %u,\n\t\tdigest %08x%08x%08x%08x", 368 EXTRACT_16BITS(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET), 369 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET), 370 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4), 371 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8), 372 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12))); 373 374 ND_PRINT((ndo, "\n\tAgreement num %d, Discarded Agreement num %d, Agreement valid-" 375 "flag %d,\n\tRestricted role-flag: %d, Format id %d cap %d, " 376 "Convention id %d cap %d,\n\tEdge count %d, " 377 "Agreement digest %08x%08x%08x%08x%08x\n", 378 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>6, 379 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>4 & 0x3, 380 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>3 & 0x1, 381 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>2 & 0x1, 382 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]>>4, 383 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]&0x00ff, 384 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]>>4, 385 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]&0x00ff, 386 EXTRACT_16BITS(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET), 387 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET), 388 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+4), 389 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+8), 390 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+12), 391 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+16))); 392 return 1; 393 394 trunc: 395 return 0; 396 } 397 398 /* 399 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets. 400 */ 401 void 402 stp_print(netdissect_options *ndo, const u_char *p, u_int length) 403 { 404 const struct stp_bpdu_ *stp_bpdu; 405 u_int mstp_len; 406 u_int spb_len; 407 408 stp_bpdu = (const struct stp_bpdu_*)p; 409 410 /* Minimum STP Frame size. */ 411 if (length < 4) 412 goto trunc; 413 414 ND_TCHECK(stp_bpdu->protocol_id); 415 if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) { 416 ND_PRINT((ndo, "unknown STP version, length %u", length)); 417 return; 418 } 419 420 ND_TCHECK(stp_bpdu->protocol_version); 421 ND_PRINT((ndo, "STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)", 422 stp_bpdu->protocol_version))); 423 424 switch (stp_bpdu->protocol_version) { 425 case STP_PROTO_REGULAR: 426 case STP_PROTO_RAPID: 427 case STP_PROTO_MSTP: 428 case STP_PROTO_SPB: 429 break; 430 default: 431 return; 432 } 433 434 ND_TCHECK(stp_bpdu->bpdu_type); 435 ND_PRINT((ndo, ", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)", 436 stp_bpdu->bpdu_type))); 437 438 switch (stp_bpdu->bpdu_type) { 439 case STP_BPDU_TYPE_CONFIG: 440 if (length < sizeof(struct stp_bpdu_) - 1) { 441 goto trunc; 442 } 443 if (!stp_print_config_bpdu(ndo, stp_bpdu, length)) 444 goto trunc; 445 break; 446 447 case STP_BPDU_TYPE_RSTP: 448 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) { 449 if (length < sizeof(struct stp_bpdu_)) { 450 goto trunc; 451 } 452 if (!stp_print_config_bpdu(ndo, stp_bpdu, length)) 453 goto trunc; 454 } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP || 455 stp_bpdu->protocol_version == STP_PROTO_SPB) { 456 if (length < STP_BPDU_MSTP_MIN_LEN) { 457 goto trunc; 458 } 459 460 ND_TCHECK(stp_bpdu->v1_length); 461 if (stp_bpdu->v1_length != 0) { 462 /* FIX ME: Emit a message here ? */ 463 goto trunc; 464 } 465 466 /* Validate v3 length */ 467 ND_TCHECK_16BITS(p + MST_BPDU_VER3_LEN_OFFSET); 468 mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET); 469 mstp_len += 2; /* length encoding itself is 2 bytes */ 470 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) { 471 goto trunc; 472 } 473 if (!stp_print_mstp_bpdu(ndo, stp_bpdu, length)) 474 goto trunc; 475 476 if (stp_bpdu->protocol_version == STP_PROTO_SPB) 477 { 478 /* Validate v4 length */ 479 ND_TCHECK_16BITS(p + MST_BPDU_VER3_LEN_OFFSET + mstp_len); 480 spb_len = EXTRACT_16BITS (p + MST_BPDU_VER3_LEN_OFFSET + mstp_len); 481 spb_len += 2; 482 if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) || 483 spb_len < SPB_BPDU_MIN_LEN) { 484 goto trunc; 485 } 486 if (!stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len))) 487 goto trunc; 488 } 489 } 490 break; 491 492 case STP_BPDU_TYPE_TOPO_CHANGE: 493 /* always empty message - just break out */ 494 break; 495 496 default: 497 break; 498 } 499 500 return; 501 trunc: 502 ND_PRINT((ndo, "[|stp %d]", length)); 503 } 504 505 /* 506 * Local Variables: 507 * c-style: whitesmith 508 * c-basic-offset: 4 509 * End: 510 */ 511
