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