The Tcpdump Group git mirrors - tcpdump/blob - print-vtp.c

   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 /* \summary: Cisco VLAN Trunking Protocol (VTP) printer */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include "netdissect-stdinc.h"
  29
  30 #include "netdissect.h"
  31 #include "addrtoname.h"
  32 #include "extract.h"
  33
  34 #define VTP_HEADER_LEN                  36
  35 #define VTP_DOMAIN_NAME_LEN             32
  36 #define VTP_MD5_DIGEST_LEN              16
  37 #define VTP_UPDATE_TIMESTAMP_LEN        12
  38 #define VTP_VLAN_INFO_FIXED_PART_LEN    12      /* length of VLAN info before VLAN name */
  39
  40 #define VTP_SUMMARY_ADV                 0x01
  41 #define VTP_SUBSET_ADV                  0x02
  42 #define VTP_ADV_REQUEST                 0x03
  43 #define VTP_JOIN_MESSAGE                0x04
  44
  45 struct vtp_vlan_ {
  46     nd_uint8_t  len;
  47     nd_uint8_t  status;
  48     nd_uint8_t  type;
  49     nd_uint8_t  name_len;
  50     nd_uint16_t vlanid;
  51     nd_uint16_t mtu;
  52     nd_uint32_t index;
  53 };
  54
  55 static const struct tok vtp_message_type_values[] = {
  56     { VTP_SUMMARY_ADV, "Summary advertisement"},
  57     { VTP_SUBSET_ADV, "Subset advertisement"},
  58     { VTP_ADV_REQUEST, "Advertisement request"},
  59     { VTP_JOIN_MESSAGE, "Join message"},
  60     { 0, NULL }
  61 };
  62
  63 static const struct tok vtp_header_values[] = {
  64     { 0x01, "Followers"}, /* On Summary advertisement, 3rd byte is Followers */
  65     { 0x02, "Seq number"}, /* On Subset  advertisement, 3rd byte is Sequence number */
  66     { 0x03, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
  67     { 0x04, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */
  68     { 0, NULL }
  69 };
  70
  71 static const struct tok vtp_vlan_type_values[] = {
  72     { 0x01, "Ethernet"},
  73     { 0x02, "FDDI"},
  74     { 0x03, "TrCRF"},
  75     { 0x04, "FDDI-net"},
  76     { 0x05, "TrBRF"},
  77     { 0, NULL }
  78 };
  79
  80 static const struct tok vtp_vlan_status[] = {
  81     { 0x00, "Operational"},
  82     { 0x01, "Suspended"},
  83     { 0, NULL }
  84 };
  85
  86 #define VTP_VLAN_SOURCE_ROUTING_RING_NUMBER      0x01
  87 #define VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER    0x02
  88 #define VTP_VLAN_STP_TYPE                        0x03
  89 #define VTP_VLAN_PARENT_VLAN                     0x04
  90 #define VTP_VLAN_TRANS_BRIDGED_VLAN              0x05
  91 #define VTP_VLAN_PRUNING                         0x06
  92 #define VTP_VLAN_BRIDGE_TYPE                     0x07
  93 #define VTP_VLAN_ARP_HOP_COUNT                   0x08
  94 #define VTP_VLAN_STE_HOP_COUNT                   0x09
  95 #define VTP_VLAN_BACKUP_CRF_MODE                 0x0A
  96
  97 static const struct tok vtp_vlan_tlv_values[] = {
  98     { VTP_VLAN_SOURCE_ROUTING_RING_NUMBER, "Source-Routing Ring Number TLV"},
  99     { VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER, "Source-Routing Bridge Number TLV"},
 100     { VTP_VLAN_STP_TYPE, "STP type TLV"},
 101     { VTP_VLAN_PARENT_VLAN, "Parent VLAN TLV"},
 102     { VTP_VLAN_TRANS_BRIDGED_VLAN, "Translationally bridged VLANs TLV"},
 103     { VTP_VLAN_PRUNING, "Pruning TLV"},
 104     { VTP_VLAN_BRIDGE_TYPE, "Bridge Type TLV"},
 105     { VTP_VLAN_ARP_HOP_COUNT, "Max ARP Hop Count TLV"},
 106     { VTP_VLAN_STE_HOP_COUNT, "Max STE Hop Count TLV"},
 107     { VTP_VLAN_BACKUP_CRF_MODE, "Backup CRF Mode TLV"},
 108     { 0,                                  NULL }
 109 };
 110
 111 static const struct tok vtp_stp_type_values[] = {
 112     { 1, "SRT"},
 113     { 2, "SRB"},
 114     { 3, "Auto"},
 115     { 0, NULL }
 116 };
 117
 118 void
 119 vtp_print(netdissect_options *ndo,
 120           const u_char *pptr, u_int length)
 121 {
 122     u_int type, len, name_len, tlv_len, tlv_value, mgmtd_len;
 123     const u_char *tptr;
 124     const struct vtp_vlan_ *vtp_vlan;
 125
 126     ndo->ndo_protocol = "vtp";
 127     if (length < VTP_HEADER_LEN)
 128         goto trunc;
 129
 130     tptr = pptr;
 131
 132     ND_TCHECK_LEN(tptr, VTP_HEADER_LEN);
 133
 134     type = GET_U_1(tptr + 1);
 135     ND_PRINT("VTPv%u, Message %s (0x%02x), length %u",
 136            GET_U_1(tptr),
 137            tok2str(vtp_message_type_values,"Unknown message type", type),
 138            type,
 139            length);
 140
 141     /* In non-verbose mode, just print version and message type */
 142     if (ndo->ndo_vflag < 1) {
 143         return;
 144     }
 145
 146     /* verbose mode print all fields */
 147     ND_PRINT("\n\tDomain name: ");
 148     mgmtd_len = GET_U_1(tptr + 3);
 149     if (mgmtd_len < 1 ||  mgmtd_len > 32) {
 150         ND_PRINT(" [invalid MgmtD Len %u]", mgmtd_len);
 151         return;
 152     }
 153     nd_printzp(ndo, tptr + 4, mgmtd_len, NULL);
 154     ND_PRINT(", %s: %u",
 155            tok2str(vtp_header_values, "Unknown", type),
 156            GET_U_1(tptr + 2));
 157
 158     tptr += VTP_HEADER_LEN;
 159
 160     switch (type) {
 161
 162     case VTP_SUMMARY_ADV:
 163
 164         /*
 165          *  SUMMARY ADVERTISEMENT
 166          *
 167          *  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
 168          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 169          *  |     Version   |     Code      |    Followers  |    MgmtD Len  |
 170          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 171          *  |       Management Domain Name  (zero-padded to 32 bytes)       |
 172          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 173          *  |                    Configuration revision number              |
 174          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 175          *  |                  Updater Identity IP address                  |
 176          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 177          *  |                    Update Timestamp (12 bytes)                |
 178          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 179          *  |                        MD5 digest (16 bytes)                  |
 180          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 181          *
 182          */
 183
 184         ND_TCHECK_8(tptr);
 185         ND_PRINT("\n\t  Config Rev %x, Updater %s",
 186                GET_BE_U_4(tptr),
 187                GET_IPADDR_STRING(tptr+4));
 188         tptr += 8;
 189         ND_TCHECK_LEN(tptr, VTP_UPDATE_TIMESTAMP_LEN);
 190         ND_PRINT(", Timestamp 0x%08x 0x%08x 0x%08x",
 191                GET_BE_U_4(tptr),
 192                GET_BE_U_4(tptr + 4),
 193                GET_BE_U_4(tptr + 8));
 194         tptr += VTP_UPDATE_TIMESTAMP_LEN;
 195         ND_TCHECK_LEN(tptr, VTP_MD5_DIGEST_LEN);
 196         ND_PRINT(", MD5 digest: %08x%08x%08x%08x",
 197                GET_BE_U_4(tptr),
 198                GET_BE_U_4(tptr + 4),
 199                GET_BE_U_4(tptr + 8),
 200                GET_BE_U_4(tptr + 12));
 201         tptr += VTP_MD5_DIGEST_LEN;
 202         break;
 203
 204     case VTP_SUBSET_ADV:
 205
 206         /*
 207          *  SUBSET ADVERTISEMENT
 208          *
 209          *  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
 210          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 211          *  |     Version   |     Code      |   Seq number  |    MgmtD Len  |
 212          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 213          *  |       Management Domain Name  (zero-padded to 32 bytes)       |
 214          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 215          *  |                    Configuration revision number              |
 216          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 217          *  |                         VLAN info field 1                     |
 218          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 219          *  |                         ................                      |
 220          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 221          *  |                         VLAN info field N                     |
 222          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 223          *
 224          */
 225
 226         ND_PRINT(", Config Rev %x", GET_BE_U_4(tptr));
 227
 228         /*
 229          *  VLAN INFORMATION
 230          *  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
 231          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 232          *  | V info len    |    Status     |  VLAN type    | VLAN name len |
 233          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 234          *  |       ISL vlan id             |            MTU size           |
 235          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 236          *  |                     802.10 index (SAID)                       |
 237          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 238          *  |                         VLAN name                             |
 239          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 240          *
 241          */
 242
 243         tptr += 4;
 244         while ((unsigned)(tptr - pptr) < length) {
 245
 246             len = GET_U_1(tptr);
 247             if (len == 0)
 248                 break;
 249
 250             ND_TCHECK_LEN(tptr, len);
 251
 252             vtp_vlan = (const struct vtp_vlan_*)tptr;
 253             if (len < VTP_VLAN_INFO_FIXED_PART_LEN)
 254                 goto trunc;
 255             ND_TCHECK_SIZE(vtp_vlan);
 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 trunc;
 267             ND_TCHECK_LEN(tptr, name_len);
 268             nd_printzp(ndo, tptr, name_len, NULL);
 269
 270             /*
 271              * Vlan names are aligned to 32-bit boundaries.
 272              */
 273             len  -= 4*((name_len + 3)/4);
 274             tptr += 4*((name_len + 3)/4);
 275
 276             /* TLV information follows */
 277
 278             while (len > 0) {
 279
 280                 /*
 281                  * Cisco specs say 2 bytes for type + 2 bytes for length;
 282                  * see https://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
 283                  * However, actual packets on the wire appear to use 1
 284                  * byte for the type and 1 byte for the length, so that's
 285                  * what we do.
 286                  */
 287                 if (len < 2)
 288                     goto trunc;
 289                 ND_TCHECK_2(tptr);
 290                 type = GET_U_1(tptr);
 291                 tlv_len = GET_U_1(tptr + 1);
 292
 293                 ND_PRINT("\n\t\t%s (0x%04x) TLV",
 294                        tok2str(vtp_vlan_tlv_values, "Unknown", type),
 295                        type);
 296
 297                 if (len < tlv_len * 2 + 2) {
 298                     ND_PRINT(" (TLV goes past the end of the packet)");
 299                     return;
 300                 }
 301                 ND_TCHECK_LEN(tptr, tlv_len * 2 + 2);
 302
 303                 /*
 304                  * We assume the value is a 2-byte integer; the length is
 305                  * in units of 16-bit words.
 306                  */
 307                 if (tlv_len != 1) {
 308                     ND_PRINT(" (invalid TLV length %u != 1)", tlv_len);
 309                     return;
 310                 } else {
 311                     tlv_value = GET_BE_U_2(tptr + 2);
 312
 313                     switch (type) {
 314                     case VTP_VLAN_STE_HOP_COUNT:
 315                         ND_PRINT(", %u", tlv_value);
 316                         break;
 317
 318                     case VTP_VLAN_PRUNING:
 319                         ND_PRINT(", %s (%u)",
 320                                tlv_value == 1 ? "Enabled" : "Disabled",
 321                                tlv_value);
 322                         break;
 323
 324                     case VTP_VLAN_STP_TYPE:
 325                         ND_PRINT(", %s (%u)",
 326                                tok2str(vtp_stp_type_values, "Unknown", tlv_value),
 327                                tlv_value);
 328                         break;
 329
 330                     case VTP_VLAN_BRIDGE_TYPE:
 331                         ND_PRINT(", %s (%u)",
 332                                tlv_value == 1 ? "SRB" : "SRT",
 333                                tlv_value);
 334                         break;
 335
 336                     case VTP_VLAN_BACKUP_CRF_MODE:
 337                         ND_PRINT(", %s (%u)",
 338                                tlv_value == 1 ? "Backup" : "Not backup",
 339                                tlv_value);
 340                         break;
 341
 342                         /*
 343                          * FIXME those are the defined TLVs that lack a decoder
 344                          * you are welcome to contribute code ;-)
 345                          */
 346
 347                     case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER:
 348                     case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER:
 349                     case VTP_VLAN_PARENT_VLAN:
 350                     case VTP_VLAN_TRANS_BRIDGED_VLAN:
 351                     case VTP_VLAN_ARP_HOP_COUNT:
 352                     default:
 353                         print_unknown_data(ndo, tptr, "\n\t\t  ", 2 + tlv_len*2);
 354                         break;
 355                     }
 356                 }
 357                 len -= 2 + tlv_len*2;
 358                 tptr += 2 + tlv_len*2;
 359             }
 360         }
 361         break;
 362
 363     case VTP_ADV_REQUEST:
 364
 365         /*
 366          *  ADVERTISEMENT REQUEST
 367          *
 368          *  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
 369          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 370          *  |     Version   |     Code      |   Reserved    |    MgmtD Len  |
 371          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 372          *  |       Management Domain Name  (zero-padded to 32 bytes)       |
 373          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 374          *  |                          Start value                          |
 375          *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 376          *
 377          */
 378
 379         ND_PRINT("\n\tStart value: %u", GET_BE_U_4(tptr));
 380         break;
 381
 382     case VTP_JOIN_MESSAGE:
 383
 384         /* FIXME - Could not find message format */
 385         break;
 386
 387     default:
 388         break;
 389     }
 390
 391     return;
 392
 393  trunc:
 394     nd_print_trunc(ndo);
 395 }