1 /* 2 * Copyright (c) 1998-2007 The TCPDUMP project 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that: (1) source code 6 * distributions retain the above copyright notice and this paragraph 7 * in its entirety, and (2) distributions including binary code include 8 * the above copyright notice and this paragraph in its entirety in 9 * the documentation or other materials provided with the distribution. 10 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND 11 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT 12 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 13 * FOR A PARTICULAR PURPOSE. 14 * 15 * Reference documentation: 16 * https://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html 17 * https://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm 18 * 19 * Original code ode by Carles Kishimoto <carles.kishimoto@gmail.com> 20 */ 21 22 #include <sys/cdefs.h> 23 #ifndef lint 24 __RCSID("$NetBSD: print-vtp.c,v 1.7 2024/09/02 16:15:33 christos Exp $"); 25 #endif 26 27 /* \summary: Cisco VLAN Trunking Protocol (VTP) printer */ 28 29 #include <config.h> 30 31 #include "netdissect-stdinc.h" 32 33 #define ND_LONGJMP_FROM_TCHECK 34 #include "netdissect.h" 35 #include "addrtoname.h" 36 #include "extract.h" 37 38 #define VTP_HEADER_LEN 36 39 #define VTP_DOMAIN_NAME_LEN 32 40 #define VTP_MD5_DIGEST_LEN 16 41 #define VTP_UPDATE_TIMESTAMP_LEN 12 42 #define VTP_VLAN_INFO_FIXED_PART_LEN 12 /* length of VLAN info before VLAN name */ 43 44 #define VTP_SUMMARY_ADV 0x01 45 #define VTP_SUBSET_ADV 0x02 46 #define VTP_ADV_REQUEST 0x03 47 #define VTP_JOIN_MESSAGE 0x04 48 49 struct vtp_vlan_ { 50 nd_uint8_t len; 51 nd_uint8_t status; 52 nd_uint8_t type; 53 nd_uint8_t name_len; 54 nd_uint16_t vlanid; 55 nd_uint16_t mtu; 56 nd_uint32_t index; 57 }; 58 59 static const struct tok vtp_message_type_values[] = { 60 { VTP_SUMMARY_ADV, "Summary advertisement"}, 61 { VTP_SUBSET_ADV, "Subset advertisement"}, 62 { VTP_ADV_REQUEST, "Advertisement request"}, 63 { VTP_JOIN_MESSAGE, "Join message"}, 64 { 0, NULL } 65 }; 66 67 static const struct tok vtp_header_values[] = { 68 { 0x01, "Followers"}, /* On Summary advertisement, 3rd byte is Followers */ 69 { 0x02, "Seq number"}, /* On Subset advertisement, 3rd byte is Sequence number */ 70 { 0x03, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */ 71 { 0x04, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */ 72 { 0, NULL } 73 }; 74 75 static const struct tok vtp_vlan_type_values[] = { 76 { 0x01, "Ethernet"}, 77 { 0x02, "FDDI"}, 78 { 0x03, "TrCRF"}, 79 { 0x04, "FDDI-net"}, 80 { 0x05, "TrBRF"}, 81 { 0, NULL } 82 }; 83 84 static const struct tok vtp_vlan_status[] = { 85 { 0x00, "Operational"}, 86 { 0x01, "Suspended"}, 87 { 0, NULL } 88 }; 89 90 #define VTP_VLAN_SOURCE_ROUTING_RING_NUMBER 0x01 91 #define VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER 0x02 92 #define VTP_VLAN_STP_TYPE 0x03 93 #define VTP_VLAN_PARENT_VLAN 0x04 94 #define VTP_VLAN_TRANS_BRIDGED_VLAN 0x05 95 #define VTP_VLAN_PRUNING 0x06 96 #define VTP_VLAN_BRIDGE_TYPE 0x07 97 #define VTP_VLAN_ARP_HOP_COUNT 0x08 98 #define VTP_VLAN_STE_HOP_COUNT 0x09 99 #define VTP_VLAN_BACKUP_CRF_MODE 0x0A 100 101 static const struct tok vtp_vlan_tlv_values[] = { 102 { VTP_VLAN_SOURCE_ROUTING_RING_NUMBER, "Source-Routing Ring Number TLV"}, 103 { VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER, "Source-Routing Bridge Number TLV"}, 104 { VTP_VLAN_STP_TYPE, "STP type TLV"}, 105 { VTP_VLAN_PARENT_VLAN, "Parent VLAN TLV"}, 106 { VTP_VLAN_TRANS_BRIDGED_VLAN, "Translationally bridged VLANs TLV"}, 107 { VTP_VLAN_PRUNING, "Pruning TLV"}, 108 { VTP_VLAN_BRIDGE_TYPE, "Bridge Type TLV"}, 109 { VTP_VLAN_ARP_HOP_COUNT, "Max ARP Hop Count TLV"}, 110 { VTP_VLAN_STE_HOP_COUNT, "Max STE Hop Count TLV"}, 111 { VTP_VLAN_BACKUP_CRF_MODE, "Backup CRF Mode TLV"}, 112 { 0, NULL } 113 }; 114 115 static const struct tok vtp_stp_type_values[] = { 116 { 1, "SRT"}, 117 { 2, "SRB"}, 118 { 3, "Auto"}, 119 { 0, NULL } 120 }; 121 122 void 123 vtp_print(netdissect_options *ndo, 124 const u_char *pptr, const u_int length) 125 { 126 u_int type, len, name_len, tlv_len, tlv_value, mgmtd_len; 127 const u_char *tptr; 128 const struct vtp_vlan_ *vtp_vlan; 129 130 ndo->ndo_protocol = "vtp"; 131 if (length < VTP_HEADER_LEN) 132 goto invalid; 133 134 tptr = pptr; 135 136 ND_TCHECK_LEN(tptr, VTP_HEADER_LEN); 137 138 type = GET_U_1(tptr + 1); 139 ND_PRINT("VTPv%u, Message %s (0x%02x), length %u", 140 GET_U_1(tptr), 141 tok2str(vtp_message_type_values,"Unknown message type", type), 142 type, 143 length); 144 145 /* In non-verbose mode, just print version and message type */ 146 if (ndo->ndo_vflag < 1) { 147 goto tcheck_full_packet; 148 } 149 150 /* verbose mode print all fields */ 151 ND_PRINT("\n\tDomain name: "); 152 mgmtd_len = GET_U_1(tptr + 3); 153 if (mgmtd_len < 1 || mgmtd_len > VTP_DOMAIN_NAME_LEN) { 154 ND_PRINT(" [MgmtD Len %u]", mgmtd_len); 155 goto invalid; 156 } 157 nd_printjnp(ndo, tptr + 4, mgmtd_len); 158 ND_PRINT(", %s: %u", 159 tok2str(vtp_header_values, "Unknown", type), 160 GET_U_1(tptr + 2)); 161 162 tptr += VTP_HEADER_LEN; 163 164 switch (type) { 165 166 case VTP_SUMMARY_ADV: 167 168 /* 169 * SUMMARY ADVERTISEMENT 170 * 171 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 172 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 173 * | Version | Code | Followers | MgmtD Len | 174 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 * | Management Domain Name (zero-padded to 32 bytes) | 176 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 177 * | Configuration revision number | 178 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 * | Updater Identity IP address | 180 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 181 * | Update Timestamp (12 bytes) | 182 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 * | MD5 digest (16 bytes) | 184 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 185 * 186 */ 187 188 ND_PRINT("\n\t Config Rev %x, Updater %s", 189 GET_BE_U_4(tptr), 190 GET_IPADDR_STRING(tptr+4)); 191 tptr += 8; 192 ND_PRINT(", Timestamp 0x%08x 0x%08x 0x%08x", 193 GET_BE_U_4(tptr), 194 GET_BE_U_4(tptr + 4), 195 GET_BE_U_4(tptr + 8)); 196 tptr += VTP_UPDATE_TIMESTAMP_LEN; 197 ND_PRINT(", MD5 digest: %08x%08x%08x%08x", 198 GET_BE_U_4(tptr), 199 GET_BE_U_4(tptr + 4), 200 GET_BE_U_4(tptr + 8), 201 GET_BE_U_4(tptr + 12)); 202 tptr += VTP_MD5_DIGEST_LEN; 203 break; 204 205 case VTP_SUBSET_ADV: 206 207 /* 208 * SUBSET ADVERTISEMENT 209 * 210 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 211 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 * | Version | Code | Seq number | MgmtD Len | 213 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 * | Management Domain Name (zero-padded to 32 bytes) | 215 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 216 * | Configuration revision number | 217 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 218 * | VLAN info field 1 | 219 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 220 * | ................ | 221 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 222 * | VLAN info field N | 223 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 224 * 225 */ 226 227 ND_PRINT(", Config Rev %x", GET_BE_U_4(tptr)); 228 229 /* 230 * VLAN INFORMATION 231 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 232 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 233 * | V info len | Status | VLAN type | VLAN name len | 234 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 235 * | ISL vlan id | MTU size | 236 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 237 * | 802.10 index (SAID) | 238 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 239 * | VLAN name | 240 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 241 * 242 */ 243 244 tptr += 4; 245 while ((unsigned)(tptr - pptr) < length) { 246 247 len = GET_U_1(tptr); 248 if (len == 0) 249 break; 250 251 ND_TCHECK_LEN(tptr, len); 252 253 vtp_vlan = (const struct vtp_vlan_*)tptr; 254 if (len < VTP_VLAN_INFO_FIXED_PART_LEN) 255 goto invalid; 256 ND_PRINT("\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ", 257 tok2str(vtp_vlan_status,"Unknown",GET_U_1(vtp_vlan->status)), 258 tok2str(vtp_vlan_type_values,"Unknown",GET_U_1(vtp_vlan->type)), 259 GET_BE_U_2(vtp_vlan->vlanid), 260 GET_BE_U_2(vtp_vlan->mtu), 261 GET_BE_U_4(vtp_vlan->index)); 262 len -= VTP_VLAN_INFO_FIXED_PART_LEN; 263 tptr += VTP_VLAN_INFO_FIXED_PART_LEN; 264 name_len = GET_U_1(vtp_vlan->name_len); 265 if (len < 4*((name_len + 3)/4)) 266 goto invalid; 267 nd_printjnp(ndo, tptr, name_len); 268 269 /* 270 * Vlan names are aligned to 32-bit boundaries. 271 */ 272 len -= 4*((name_len + 3)/4); 273 tptr += 4*((name_len + 3)/4); 274 275 /* TLV information follows */ 276 277 while (len > 0) { 278 279 /* 280 * Cisco specs say 2 bytes for type + 2 bytes for length; 281 * see https://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm 282 * However, actual packets on the wire appear to use 1 283 * byte for the type and 1 byte for the length, so that's 284 * what we do. 285 */ 286 if (len < 2) 287 goto invalid; 288 type = GET_U_1(tptr); 289 tlv_len = GET_U_1(tptr + 1); 290 291 ND_PRINT("\n\t\t%s (0x%04x) TLV", 292 tok2str(vtp_vlan_tlv_values, "Unknown", type), 293 type); 294 295 if (len < tlv_len * 2 + 2) { 296 ND_PRINT(" (TLV goes past the end of the packet)"); 297 goto invalid; 298 } 299 ND_TCHECK_LEN(tptr, tlv_len * 2 + 2); 300 301 /* 302 * We assume the value is a 2-byte integer; the length is 303 * in units of 16-bit words. 304 */ 305 if (tlv_len != 1) { 306 ND_PRINT(" [TLV length %u != 1]", tlv_len); 307 goto invalid; 308 } else { 309 tlv_value = GET_BE_U_2(tptr + 2); 310 311 switch (type) { 312 case VTP_VLAN_STE_HOP_COUNT: 313 ND_PRINT(", %u", tlv_value); 314 break; 315 316 case VTP_VLAN_PRUNING: 317 ND_PRINT(", %s (%u)", 318 tlv_value == 1 ? "Enabled" : "Disabled", 319 tlv_value); 320 break; 321 322 case VTP_VLAN_STP_TYPE: 323 ND_PRINT(", %s (%u)", 324 tok2str(vtp_stp_type_values, "Unknown", tlv_value), 325 tlv_value); 326 break; 327 328 case VTP_VLAN_BRIDGE_TYPE: 329 ND_PRINT(", %s (%u)", 330 tlv_value == 1 ? "SRB" : "SRT", 331 tlv_value); 332 break; 333 334 case VTP_VLAN_BACKUP_CRF_MODE: 335 ND_PRINT(", %s (%u)", 336 tlv_value == 1 ? "Backup" : "Not backup", 337 tlv_value); 338 break; 339 340 /* 341 * FIXME those are the defined TLVs that lack a decoder 342 * you are welcome to contribute code ;-) 343 */ 344 345 case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER: 346 case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER: 347 case VTP_VLAN_PARENT_VLAN: 348 case VTP_VLAN_TRANS_BRIDGED_VLAN: 349 case VTP_VLAN_ARP_HOP_COUNT: 350 default: 351 print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2); 352 break; 353 } 354 } 355 len -= 2 + tlv_len*2; 356 tptr += 2 + tlv_len*2; 357 } 358 } 359 break; 360 361 case VTP_ADV_REQUEST: 362 363 /* 364 * ADVERTISEMENT REQUEST 365 * 366 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 367 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 368 * | Version | Code | Reserved | MgmtD Len | 369 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 370 * | Management Domain Name (zero-padded to 32 bytes) | 371 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 372 * | Start value | 373 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 374 * 375 */ 376 377 ND_PRINT("\n\tStart value: %u", GET_BE_U_4(tptr)); 378 break; 379 380 case VTP_JOIN_MESSAGE: 381 382 /* FIXME - Could not find message format */ 383 break; 384 385 default: 386 break; 387 } 388 389 return; 390 391 invalid: 392 nd_print_invalid(ndo); 393 tcheck_full_packet: 394 ND_TCHECK_LEN(pptr, length); 395 } 396