print-stp.c revision 1.8
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 1.8 2017/09/08 14:01:13 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 uint8_t protocol_id[2]; 36 uint8_t protocol_version; 37 uint8_t bpdu_type; 38 uint8_t flags; 39 uint8_t root_id[8]; 40 uint8_t root_path_cost[4]; 41 uint8_t bridge_id[8]; 42 uint8_t port_id[2]; 43 uint8_t message_age[2]; 44 uint8_t max_age[2]; 45 uint8_t hello_time[2]; 46 uint8_t forward_delay[2]; 47 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 #define ND_TCHECK_BRIDGE_ID(p) ND_TCHECK2(*(p), 8) 93 94 static char * 95 stp_print_bridge_id(const u_char *p) 96 { 97 static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")]; 98 99 snprintf(bridge_id_str, sizeof(bridge_id_str), 100 "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x", 101 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]); 102 103 return bridge_id_str; 104 } 105 106 static int 107 stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 108 u_int length) 109 { 110 ND_TCHECK(stp_bpdu->flags); 111 ND_PRINT((ndo, ", Flags [%s]", 112 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags))); 113 114 ND_TCHECK(stp_bpdu->port_id); 115 ND_PRINT((ndo, ", bridge-id %s.%04x, length %u", 116 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id), 117 EXTRACT_16BITS(&stp_bpdu->port_id), length)); 118 119 /* in non-verbose mode just print the bridge-id */ 120 if (!ndo->ndo_vflag) { 121 return 1; 122 } 123 124 ND_TCHECK(stp_bpdu->forward_delay); 125 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs" 126 ", hello-time %.2fs, forwarding-delay %.2fs", 127 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE, 128 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE, 129 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE, 130 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE)); 131 132 ND_PRINT((ndo, "\n\troot-id %s, root-pathcost %u", 133 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id), 134 EXTRACT_32BITS(&stp_bpdu->root_path_cost))); 135 136 /* Port role is only valid for 802.1w */ 137 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) { 138 ND_PRINT((ndo, ", port-role %s", 139 tok2str(rstp_obj_port_role_values, "Unknown", 140 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)))); 141 } 142 return 1; 143 144 trunc: 145 return 0; 146 } 147 148 /* 149 * MSTP packet format 150 * Ref. IEEE 802.1Q 2003 Ed. Section 14 151 * 152 * MSTP BPDU 153 * 154 * 2 - bytes Protocol Id 155 * 1 - byte Protocol Ver. 156 * 1 - byte BPDU tye 157 * 1 - byte Flags 158 * 8 - bytes CIST Root Identifier 159 * 4 - bytes CIST External Path Cost 160 * 8 - bytes CIST Regional Root Identifier 161 * 2 - bytes CIST Port Identifier 162 * 2 - bytes Message Age 163 * 2 - bytes Max age 164 * 2 - bytes Hello Time 165 * 2 - bytes Forward delay 166 * 1 - byte Version 1 length. Must be 0 167 * 2 - bytes Version 3 length 168 * 1 - byte Config Identifier 169 * 32 - bytes Config Name 170 * 2 - bytes Revision level 171 * 16 - bytes Config Digest [MD5] 172 * 4 - bytes CIST Internal Root Path Cost 173 * 8 - bytes CIST Bridge Identifier 174 * 1 - byte CIST Remaining Hops 175 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes] 176 * 177 * 178 * SPB BPDU 179 * Ref. IEEE 802.1aq. Section 14 180 * 181 * 2 - bytes Version 4 length 182 * 1 - byte Aux Config Identifier 183 * 32 - bytes Aux Config Name 184 * 2 - bytes Aux Revision level 185 * 16 - bytes Aux Config Digest [MD5] 186 * 1 - byte (1 - 2) Agreement Number 187 * (3 - 4) Discarded Agreement Number 188 * (5) Agreement Valid Flag 189 * (6) Restricted Role Flag 190 * (7 - 8) Unused sent zero 191 * 1 - byte Unused 192 * 1 - byte (1 - 4) Agreement Digest Format Identifier 193 * (5 - 8) Agreement Digest Format Capabilities 194 * 1 - byte (1 - 4) Agreement Digest Convention Identifier 195 * (5 - 8) Agreement Digest Convention Capabilities 196 * 2 - bytes Agreement Digest Edge Count 197 * 8 - byte Reserved Set 198 * 20 - bytes Computed Topology Digest 199 * 200 * 201 * MSTI Payload 202 * 203 * 1 - byte MSTI flag 204 * 8 - bytes MSTI Regional Root Identifier 205 * 4 - bytes MSTI Regional Path Cost 206 * 1 - byte MSTI Bridge Priority 207 * 1 - byte MSTI Port Priority 208 * 1 - byte MSTI Remaining Hops 209 * 210 */ 211 212 #define MST_BPDU_MSTI_LENGTH 16 213 #define MST_BPDU_CONFIG_INFO_LENGTH 64 214 215 /* Offsets of fields from the begginning for the packet */ 216 #define MST_BPDU_VER3_LEN_OFFSET 36 217 #define MST_BPDU_CONFIG_NAME_OFFSET 39 218 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73 219 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89 220 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93 221 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101 222 #define MST_BPDU_MSTI_OFFSET 102 223 /* Offsets within an MSTI */ 224 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1 225 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9 226 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13 227 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14 228 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15 229 230 #define SPB_BPDU_MIN_LEN 87 231 #define SPB_BPDU_CONFIG_NAME_OFFSET 3 232 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32 233 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2 234 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16 235 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1 236 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1 237 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1 238 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1 239 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2 240 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4 241 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4 242 243 static int 244 stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 245 u_int length) 246 { 247 const u_char *ptr; 248 uint16_t v3len; 249 uint16_t len; 250 uint16_t msti; 251 u_int offset; 252 253 ptr = (const u_char *)stp_bpdu; 254 ND_PRINT((ndo, ", CIST Flags [%s], length %u", 255 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags), length)); 256 257 /* 258 * in non-verbose mode just print the flags. 259 */ 260 if (!ndo->ndo_vflag) { 261 return 1; 262 } 263 264 ND_TCHECK(stp_bpdu->flags); 265 ND_PRINT((ndo, "\n\tport-role %s, ", 266 tok2str(rstp_obj_port_role_values, "Unknown", 267 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)))); 268 269 ND_TCHECK(stp_bpdu->root_path_cost); 270 ND_PRINT((ndo, "CIST root-id %s, CIST ext-pathcost %u", 271 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id), 272 EXTRACT_32BITS(&stp_bpdu->root_path_cost))); 273 274 ND_TCHECK(stp_bpdu->bridge_id); 275 ND_PRINT((ndo, "\n\tCIST regional-root-id %s, ", 276 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id))); 277 278 ND_TCHECK(stp_bpdu->port_id); 279 ND_PRINT((ndo, "CIST port-id %04x,", EXTRACT_16BITS(&stp_bpdu->port_id))); 280 281 ND_TCHECK(stp_bpdu->forward_delay); 282 ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs" 283 ", hello-time %.2fs, forwarding-delay %.2fs", 284 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE, 285 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE, 286 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE, 287 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE)); 288 289 ND_TCHECK_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET); 290 ND_PRINT((ndo, "\n\tv3len %d, ", EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET))); 291 ND_TCHECK_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12); 292 ND_PRINT((ndo, "MCID Name ")); 293 if (fn_printzp(ndo, ptr + MST_BPDU_CONFIG_NAME_OFFSET, 32, ndo->ndo_snapend)) 294 goto trunc; 295 ND_PRINT((ndo, ", rev %u," 296 "\n\t\tdigest %08x%08x%08x%08x, ", 297 EXTRACT_16BITS(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32), 298 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET), 299 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4), 300 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8), 301 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12))); 302 303 ND_TCHECK_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET); 304 ND_PRINT((ndo, "CIST int-root-pathcost %u,", 305 EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET))); 306 307 ND_TCHECK_BRIDGE_ID(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET); 308 ND_PRINT((ndo, "\n\tCIST bridge-id %s, ", 309 stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET))); 310 311 ND_TCHECK(ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]); 312 ND_PRINT((ndo, "CIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET])); 313 314 /* Dump all MSTI's */ 315 ND_TCHECK_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET); 316 v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET); 317 if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) { 318 len = v3len - MST_BPDU_CONFIG_INFO_LENGTH; 319 offset = MST_BPDU_MSTI_OFFSET; 320 while (len >= MST_BPDU_MSTI_LENGTH) { 321 ND_TCHECK2(*(ptr + offset), MST_BPDU_MSTI_LENGTH); 322 323 msti = EXTRACT_16BITS(ptr + offset + 324 MST_BPDU_MSTI_ROOT_PRIO_OFFSET); 325 msti = msti & 0x0FFF; 326 327 ND_PRINT((ndo, "\n\tMSTI %d, Flags [%s], port-role %s", 328 msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]), 329 tok2str(rstp_obj_port_role_values, "Unknown", 330 RSTP_EXTRACT_PORT_ROLE(ptr[offset])))); 331 ND_PRINT((ndo, "\n\t\tMSTI regional-root-id %s, pathcost %u", 332 stp_print_bridge_id(ptr + offset + 333 MST_BPDU_MSTI_ROOT_PRIO_OFFSET), 334 EXTRACT_32BITS(ptr + offset + 335 MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET))); 336 ND_PRINT((ndo, "\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d", 337 ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET] >> 4, 338 ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET] >> 4, 339 ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET])); 340 341 len -= MST_BPDU_MSTI_LENGTH; 342 offset += MST_BPDU_MSTI_LENGTH; 343 } 344 } 345 return 1; 346 347 trunc: 348 return 0; 349 } 350 351 static int 352 stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, 353 u_int offset) 354 { 355 const u_char *ptr; 356 357 /* 358 * in non-verbose mode don't print anything. 359 */ 360 if (!ndo->ndo_vflag) { 361 return 1; 362 } 363 364 ptr = (const u_char *)stp_bpdu; 365 ND_TCHECK_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 16); 366 367 ND_PRINT((ndo, "\n\tv4len %d, ", EXTRACT_16BITS (ptr + offset))); 368 ND_PRINT((ndo, "AUXMCID Name ")); 369 if (fn_printzp(ndo, ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET, 32, 370 ndo->ndo_snapend)) 371 goto trunc; 372 ND_PRINT((ndo, ", Rev %u,\n\t\tdigest %08x%08x%08x%08x", 373 EXTRACT_16BITS(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET), 374 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET), 375 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4), 376 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8), 377 EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12))); 378 379 ND_PRINT((ndo, "\n\tAgreement num %d, Discarded Agreement num %d, Agreement valid-" 380 "flag %d,\n\tRestricted role-flag: %d, Format id %d cap %d, " 381 "Convention id %d cap %d,\n\tEdge count %d, " 382 "Agreement digest %08x%08x%08x%08x%08x\n", 383 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>6, 384 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>4 & 0x3, 385 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>3 & 0x1, 386 ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>2 & 0x1, 387 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]>>4, 388 ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]&0x00ff, 389 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]>>4, 390 ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]&0x00ff, 391 EXTRACT_16BITS(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET), 392 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET), 393 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+4), 394 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+8), 395 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+12), 396 EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET+16))); 397 return 1; 398 399 trunc: 400 return 0; 401 } 402 403 /* 404 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets. 405 */ 406 void 407 stp_print(netdissect_options *ndo, const u_char *p, u_int length) 408 { 409 const struct stp_bpdu_ *stp_bpdu; 410 u_int mstp_len; 411 u_int spb_len; 412 413 stp_bpdu = (const struct stp_bpdu_*)p; 414 415 /* Minimum STP Frame size. */ 416 if (length < 4) 417 goto trunc; 418 419 ND_TCHECK(stp_bpdu->protocol_id); 420 if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) { 421 ND_PRINT((ndo, "unknown STP version, length %u", length)); 422 return; 423 } 424 425 ND_TCHECK(stp_bpdu->protocol_version); 426 ND_PRINT((ndo, "STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)", 427 stp_bpdu->protocol_version))); 428 429 switch (stp_bpdu->protocol_version) { 430 case STP_PROTO_REGULAR: 431 case STP_PROTO_RAPID: 432 case STP_PROTO_MSTP: 433 case STP_PROTO_SPB: 434 break; 435 default: 436 return; 437 } 438 439 ND_TCHECK(stp_bpdu->bpdu_type); 440 ND_PRINT((ndo, ", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)", 441 stp_bpdu->bpdu_type))); 442 443 switch (stp_bpdu->bpdu_type) { 444 case STP_BPDU_TYPE_CONFIG: 445 if (length < sizeof(struct stp_bpdu_) - 1) { 446 goto trunc; 447 } 448 if (!stp_print_config_bpdu(ndo, stp_bpdu, length)) 449 goto trunc; 450 break; 451 452 case STP_BPDU_TYPE_RSTP: 453 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) { 454 if (length < sizeof(struct stp_bpdu_)) { 455 goto trunc; 456 } 457 if (!stp_print_config_bpdu(ndo, stp_bpdu, length)) 458 goto trunc; 459 } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP || 460 stp_bpdu->protocol_version == STP_PROTO_SPB) { 461 if (length < STP_BPDU_MSTP_MIN_LEN) { 462 goto trunc; 463 } 464 465 ND_TCHECK(stp_bpdu->v1_length); 466 if (stp_bpdu->v1_length != 0) { 467 /* FIX ME: Emit a message here ? */ 468 goto trunc; 469 } 470 471 /* Validate v3 length */ 472 ND_TCHECK_16BITS(p + MST_BPDU_VER3_LEN_OFFSET); 473 mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET); 474 mstp_len += 2; /* length encoding itself is 2 bytes */ 475 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) { 476 goto trunc; 477 } 478 if (!stp_print_mstp_bpdu(ndo, stp_bpdu, length)) 479 goto trunc; 480 481 if (stp_bpdu->protocol_version == STP_PROTO_SPB) 482 { 483 /* Validate v4 length */ 484 ND_TCHECK_16BITS(p + MST_BPDU_VER3_LEN_OFFSET + mstp_len); 485 spb_len = EXTRACT_16BITS (p + MST_BPDU_VER3_LEN_OFFSET + mstp_len); 486 spb_len += 2; 487 if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) || 488 spb_len < SPB_BPDU_MIN_LEN) { 489 goto trunc; 490 } 491 if (!stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len))) 492 goto trunc; 493 } 494 } 495 break; 496 497 case STP_BPDU_TYPE_TOPO_CHANGE: 498 /* always empty message - just break out */ 499 break; 500 501 default: 502 break; 503 } 504 505 return; 506 trunc: 507 ND_PRINT((ndo, "[|stp %d]", length)); 508 } 509 510 /* 511 * Local Variables: 512 * c-style: whitesmith 513 * c-basic-offset: 4 514 * End: 515 */ 516
Indexes created Sat Aug 15 00:25:12 UTC 2026