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