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@gnu.org> 10 */ 11 12 #include <sys/cdefs.h> 13 #ifndef lint 14 #if 0 15 static const char rcsid[] _U_ = 16 "@(#) Header: /tcpdump/master/tcpdump/print-stp.c,v 1.20 2007-03-18 17:11:46 hannes Exp"; 17 #else 18 __RCSID("$NetBSD: print-stp.c,v 1.2 2010/12/05 05:11:30 christos Exp $"); 19 #endif 20 #endif 21 22 #ifdef HAVE_CONFIG_H 23 #include "config.h" 24 #endif 25 26 #include <tcpdump-stdinc.h> 27 28 #include <stdlib.h> 29 #include <stdio.h> 30 #include <string.h> 31 32 #include "interface.h" 33 #include "addrtoname.h" 34 #include "extract.h" 35 36 #define RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2) 37 /* STP timers are expressed in multiples of 1/256th second */ 38 #define STP_TIME_BASE 256 39 #define STP_BPDU_MSTP_MIN_LEN 102 40 41 struct stp_bpdu_ { 42 u_int8_t protocol_id[2]; 43 u_int8_t protocol_version; 44 u_int8_t bpdu_type; 45 u_int8_t flags; 46 u_int8_t root_id[8]; 47 u_int8_t root_path_cost[4]; 48 u_int8_t bridge_id[8]; 49 u_int8_t port_id[2]; 50 u_int8_t message_age[2]; 51 u_int8_t max_age[2]; 52 u_int8_t hello_time[2]; 53 u_int8_t forward_delay[2]; 54 u_int8_t v1_length; 55 }; 56 57 #define STP_PROTO_REGULAR 0x00 58 #define STP_PROTO_RAPID 0x02 59 #define STP_PROTO_MSTP 0x03 60 61 struct tok stp_proto_values[] = { 62 { STP_PROTO_REGULAR, "802.1d" }, 63 { STP_PROTO_RAPID, "802.1w" }, 64 { STP_PROTO_MSTP, "802.1s" }, 65 { 0, NULL} 66 }; 67 68 #define STP_BPDU_TYPE_CONFIG 0x00 69 #define STP_BPDU_TYPE_RSTP 0x02 70 #define STP_BPDU_TYPE_TOPO_CHANGE 0x80 71 72 struct tok stp_bpdu_flag_values[] = { 73 { 0x01, "Topology change" }, 74 { 0x02, "Proposal" }, 75 { 0x10, "Learn" }, 76 { 0x20, "Forward" }, 77 { 0x40, "Agreement" }, 78 { 0x80, "Topology change ACK" }, 79 { 0, NULL} 80 }; 81 82 struct tok stp_bpdu_type_values[] = { 83 { STP_BPDU_TYPE_CONFIG, "Config" }, 84 { STP_BPDU_TYPE_RSTP, "Rapid STP" }, 85 { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" }, 86 { 0, NULL} 87 }; 88 89 struct tok rstp_obj_port_role_values[] = { 90 { 0x00, "Unknown" }, 91 { 0x01, "Alternate" }, 92 { 0x02, "Root" }, 93 { 0x03, "Designated" }, 94 { 0, NULL} 95 }; 96 97 static char * 98 stp_print_bridge_id(const u_char *p) 99 { 100 static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")]; 101 102 snprintf(bridge_id_str, sizeof(bridge_id_str), 103 "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x", 104 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]); 105 106 return bridge_id_str; 107 } 108 109 static void 110 stp_print_config_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length) 111 { 112 printf(", Flags [%s]", 113 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags)); 114 115 printf(", 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 (!vflag) { 121 return; 122 } 123 124 printf("\n\tmessage-age %.2fs, max-age %.2fs" 125 ", hello-time %.2fs, forwarding-delay %.2fs", 126 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE, 127 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE, 128 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE, 129 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE); 130 131 printf("\n\troot-id %s, root-pathcost %u", 132 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id), 133 EXTRACT_32BITS(&stp_bpdu->root_path_cost)); 134 135 /* Port role is only valid for 802.1w */ 136 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) { 137 printf(", port-role %s", 138 tok2str(rstp_obj_port_role_values, "Unknown", 139 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))); 140 } 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 * MSTI Payload 173 * 174 * 1 - byte MSTI flag 175 * 8 - bytes MSTI Regional Root Identifier 176 * 4 - bytes MSTI Regional Path Cost 177 * 1 - byte MSTI Bridge Priority 178 * 1 - byte MSTI Port Priority 179 * 1 - byte MSTI Remaining Hops 180 */ 181 182 #define MST_BPDU_MSTI_LENGTH 16 183 #define MST_BPDU_CONFIG_INFO_LENGTH 64 184 185 /* Offsets of fields from the begginning for the packet */ 186 #define MST_BPDU_VER3_LEN_OFFSET 36 187 #define MST_BPDU_CONFIG_NAME_OFFSET 39 188 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73 189 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89 190 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93 191 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101 192 #define MST_BPDU_MSTI_OFFSET 102 193 /* Offsets within an MSTI */ 194 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1 195 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9 196 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13 197 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14 198 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15 199 200 static void 201 stp_print_mstp_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length) 202 { 203 const u_char *ptr; 204 u_int16_t v3len; 205 u_int16_t len; 206 u_int16_t msti; 207 u_int16_t offset; 208 209 ptr = (const u_char *)stp_bpdu; 210 printf(", CIST Flags [%s]", 211 bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags)); 212 213 /* 214 * in non-verbose mode just print the flags. We dont read that much 215 * of the packet (DEFAULT_SNAPLEN) to print out cist bridge-id 216 */ 217 if (!vflag) { 218 return; 219 } 220 221 printf(", CIST bridge-id %s.%04x, length %u", 222 stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET), 223 EXTRACT_16BITS(&stp_bpdu->port_id), length); 224 225 226 printf("\n\tmessage-age %.2fs, max-age %.2fs" 227 ", hello-time %.2fs, forwarding-delay %.2fs", 228 (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE, 229 (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE, 230 (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE, 231 (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE); 232 233 printf("\n\tCIST root-id %s, ext-pathcost %u int-pathcost %u", 234 stp_print_bridge_id((const u_char *)&stp_bpdu->root_id), 235 EXTRACT_32BITS(&stp_bpdu->root_path_cost), 236 EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET)); 237 238 printf(", port-role %s", 239 tok2str(rstp_obj_port_role_values, "Unknown", 240 RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))); 241 242 printf("\n\tCIST regional-root-id %s", 243 stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id)); 244 245 printf("\n\tMSTP Configuration Name %s, revision %u, digest %08x%08x%08x%08x", 246 ptr + MST_BPDU_CONFIG_NAME_OFFSET, 247 EXTRACT_16BITS(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32), 248 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET), 249 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4), 250 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8), 251 EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12)); 252 253 printf("\n\tCIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]); 254 255 /* Dump all MSTI's */ 256 v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET); 257 if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) { 258 len = v3len - MST_BPDU_CONFIG_INFO_LENGTH; 259 offset = MST_BPDU_MSTI_OFFSET; 260 while (len >= MST_BPDU_MSTI_LENGTH) { 261 msti = EXTRACT_16BITS(ptr + offset + 262 MST_BPDU_MSTI_ROOT_PRIO_OFFSET); 263 msti = msti & 0x0FFF; 264 265 printf("\n\tMSTI %d, Flags [%s], port-role %s", 266 msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]), 267 tok2str(rstp_obj_port_role_values, "Unknown", 268 RSTP_EXTRACT_PORT_ROLE(ptr[offset]))); 269 printf("\n\t\tMSTI regional-root-id %s, pathcost %u", 270 stp_print_bridge_id(ptr + offset + 271 MST_BPDU_MSTI_ROOT_PRIO_OFFSET), 272 EXTRACT_32BITS(ptr + offset + 273 MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET)); 274 printf("\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d", 275 ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET] >> 4, 276 ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET] >> 4, 277 ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET]); 278 279 len -= MST_BPDU_MSTI_LENGTH; 280 offset += MST_BPDU_MSTI_LENGTH; 281 } 282 } 283 } 284 285 /* 286 * Print 802.1d / 802.1w / 802.1q (mstp) packets. 287 */ 288 void 289 stp_print(const u_char *p, u_int length) 290 { 291 const struct stp_bpdu_ *stp_bpdu; 292 u_int16_t mstp_len; 293 294 stp_bpdu = (struct stp_bpdu_*)p; 295 296 /* Minimum STP Frame size. */ 297 if (length < 4) 298 goto trunc; 299 300 if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) { 301 printf("unknown STP version, length %u", length); 302 return; 303 } 304 305 printf("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)", 306 stp_bpdu->protocol_version)); 307 308 switch (stp_bpdu->protocol_version) { 309 case STP_PROTO_REGULAR: 310 case STP_PROTO_RAPID: 311 case STP_PROTO_MSTP: 312 break; 313 default: 314 return; 315 } 316 317 printf(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)", 318 stp_bpdu->bpdu_type)); 319 320 switch (stp_bpdu->bpdu_type) { 321 case STP_BPDU_TYPE_CONFIG: 322 if (length < sizeof(struct stp_bpdu_) - 1) { 323 goto trunc; 324 } 325 stp_print_config_bpdu(stp_bpdu, length); 326 break; 327 328 case STP_BPDU_TYPE_RSTP: 329 if (stp_bpdu->protocol_version == STP_PROTO_RAPID) { 330 if (length < sizeof(struct stp_bpdu_)) { 331 goto trunc; 332 } 333 stp_print_config_bpdu(stp_bpdu, length); 334 } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP) { 335 if (length < STP_BPDU_MSTP_MIN_LEN) { 336 goto trunc; 337 } 338 if (stp_bpdu->v1_length != 0) { 339 /* FIX ME: Emit a message here ? */ 340 goto trunc; 341 } 342 /* Validate v3 length */ 343 mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET); 344 mstp_len += 2; /* length encoding itself is 2 bytes */ 345 if (length < (sizeof(struct stp_bpdu_) + mstp_len)) { 346 goto trunc; 347 } 348 stp_print_mstp_bpdu(stp_bpdu, length); 349 } 350 break; 351 352 case STP_BPDU_TYPE_TOPO_CHANGE: 353 /* always empty message - just break out */ 354 break; 355 356 default: 357 break; 358 } 359 360 return; 361 trunc: 362 printf("[|stp %d]", length); 363 } 364 365 /* 366 * Local Variables: 367 * c-style: whitesmith 368 * c-basic-offset: 4 369 * End: 370 */ 371