epan/dissectors/packet-cdp.c

   1 /* packet-cdp.c
   2  * Routines for the disassembly of the "Cisco Discovery Protocol"
   3  * (c) Copyright Hannes R. Boehm <hannes@boehm.org>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include <glib.h>
  34 #include <epan/packet.h>
  35 #include <epan/strutil.h>
  36 #include <epan/in_cksum.h>
  37
  38 #include <epan/oui.h>
  39 #include <epan/nlpid.h>
  40
  41
  42 /*
  43  * See
  44  *
  45  *      http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm#xtocid12
  46  *
  47  * for some information on CDP.
  48  *
  49  * See
  50  *
  51  *      http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a0080094713.shtml#cdp
  52  *
  53  * for some more information on CDP version 2.
  54  */
  55
  56 /* Offsets in TLV structure. */
  57 #define TLV_TYPE        0
  58 #define TLV_LENGTH      2
  59
  60 static int proto_cdp = -1;
  61 static int hf_cdp_version = -1;
  62 static int hf_cdp_checksum = -1;
  63 static int hf_cdp_checksum_good = -1;
  64 static int hf_cdp_checksum_bad = -1;
  65 static int hf_cdp_ttl = -1;
  66 static int hf_cdp_tlvtype = -1;
  67 static int hf_cdp_tlvlength = -1;
  68
  69 static gint ett_cdp = -1;
  70 static gint ett_cdp_tlv = -1;
  71 static gint ett_cdp_address = -1;
  72 static gint ett_cdp_capabilities = -1;
  73 static gint ett_cdp_checksum = -1;
  74
  75 static dissector_handle_t data_handle;
  76
  77 static int
  78 dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
  79 static void
  80 dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
  81 static void
  82 add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
  83   gint len, const gchar *prefix);
  84
  85 #define TYPE_DEVICE_ID          0x0001
  86 #define TYPE_ADDRESS            0x0002
  87 #define TYPE_PORT_ID            0x0003
  88 #define TYPE_CAPABILITIES       0x0004
  89 #define TYPE_IOS_VERSION        0x0005
  90 #define TYPE_PLATFORM           0x0006
  91 #define TYPE_IP_PREFIX          0x0007
  92 #define TYPE_PROTOCOL_HELLO     0x0008 /* Protocol Hello */
  93 #define TYPE_VTP_MGMT_DOMAIN    0x0009 /* VTP Domain, CTPv2 - see second URL */
  94 #define TYPE_NATIVE_VLAN        0x000a /* Native VLAN, CTPv2 - see second URL */
  95 #define TYPE_DUPLEX             0x000b /* Full/Half Duplex - see second URL */
  96 /*                              0x000c */
  97 /*                              0x000d */
  98 #define TYPE_VOIP_VLAN_REPLY    0x000e /* VoIP VLAN reply */
  99 #define TYPE_VOIP_VLAN_QUERY    0x000f /* VoIP VLAN query */
 100 #define TYPE_POWER              0x0010 /* Power consumption */
 101 #define TYPE_MTU                0x0011 /* MTU */
 102 #define TYPE_TRUST_BITMAP       0x0012 /* Trust bitmap */
 103 #define TYPE_UNTRUSTED_COS      0x0013 /* Untrusted port CoS */
 104 #define TYPE_SYSTEM_NAME        0x0014 /* System Name */
 105 #define TYPE_SYSTEM_OID         0x0015 /* System OID */
 106 #define TYPE_MANAGEMENT_ADDR    0x0016 /* Management Address(es) */
 107 #define TYPE_LOCATION           0x0017 /* Location */
 108
 109
 110 static const value_string type_vals[] = {
 111         { TYPE_DEVICE_ID,       "Device ID" },
 112         { TYPE_ADDRESS,         "Addresses" },
 113         { TYPE_PORT_ID,         "Port ID" },
 114         { TYPE_CAPABILITIES,    "Capabilities" },
 115         { TYPE_IOS_VERSION,     "Software version" },
 116         { TYPE_PLATFORM,        "Platform" },
 117         { TYPE_IP_PREFIX,       "IP Prefix/Gateway (used for ODR)" },
 118         { TYPE_PROTOCOL_HELLO,  "Protocol Hello" },
 119         { TYPE_VTP_MGMT_DOMAIN, "VTP Management Domain" },
 120         { TYPE_NATIVE_VLAN,     "Native VLAN" },
 121         { TYPE_DUPLEX,          "Duplex" },
 122
 123         { TYPE_VOIP_VLAN_REPLY, "VoIP VLAN Reply" },
 124         { TYPE_VOIP_VLAN_QUERY, "VoIP VLAN Query" },
 125         { TYPE_POWER,           "Power consumption" },
 126         { TYPE_MTU,             "MTU"},
 127         { TYPE_TRUST_BITMAP,    "Trust Bitmap" },
 128         { TYPE_UNTRUSTED_COS,   "Untrusted Port CoS" },
 129         { TYPE_SYSTEM_NAME,     "System Name" },
 130         { TYPE_SYSTEM_OID,      "System Object ID" },
 131         { TYPE_MANAGEMENT_ADDR, "Management Address" },
 132         { TYPE_LOCATION,        "Location" },
 133         { 0,                    NULL }
 134 };
 135
 136 #define TYPE_HELLO_CLUSTER_MGMT    0x0112
 137
 138 static const value_string type_hello_vals[] = {
 139         { TYPE_HELLO_CLUSTER_MGMT,   "Cluster Management" },
 140         { 0,                    NULL }
 141 };
 142
 143 static void
 144 dissect_cdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 145 {
 146     proto_item *ti, *checksum_item;
 147     proto_tree *cdp_tree = NULL, *checksum_tree;
 148     int offset = 0;
 149     guint16 type;
 150     guint16 length, packet_checksum, computed_checksum, data_length;
 151     gboolean checksum_good, checksum_bad;
 152     proto_item *tlvi;
 153     proto_tree *tlv_tree;
 154     int real_length;
 155     guint32 naddresses;
 156     int addr_length;
 157     guint32 ip_addr;
 158     vec_t cksum_vec[1];
 159
 160     if (check_col(pinfo->cinfo, COL_PROTOCOL))
 161         col_set_str(pinfo->cinfo, COL_PROTOCOL, "CDP");
 162     if (check_col(pinfo->cinfo, COL_INFO))
 163         col_clear(pinfo->cinfo, COL_INFO);
 164
 165     if (tree){
 166         ti = proto_tree_add_item(tree, proto_cdp, tvb, offset, -1, FALSE);
 167         cdp_tree = proto_item_add_subtree(ti, ett_cdp);
 168
 169         /* CDP header */
 170         proto_tree_add_item(cdp_tree, hf_cdp_version, tvb, offset, 1, FALSE);
 171         offset += 1;
 172
 173         proto_tree_add_uint_format_value(cdp_tree, hf_cdp_ttl, tvb, offset, 1,
 174                                          tvb_get_guint8(tvb, offset),
 175                                          "%u seconds",
 176                                          tvb_get_guint8(tvb, offset));
 177         offset += 1;
 178     } else {
 179         offset += 2; /* The version/ttl fields from above */
 180     }
 181
 182     /* Checksum display & verification code */
 183     packet_checksum = tvb_get_ntohs(tvb, offset);
 184
 185     data_length = tvb_reported_length(tvb);
 186
 187     cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, data_length);
 188     cksum_vec[0].len = data_length;
 189
 190     computed_checksum = in_cksum(cksum_vec, 1);
 191     checksum_good = (computed_checksum == 0);
 192     checksum_bad = !checksum_good;
 193     if (checksum_good) {
 194         checksum_item = proto_tree_add_uint_format(cdp_tree,
 195         hf_cdp_checksum, tvb, offset, 2, packet_checksum,
 196         "Checksum: 0x%04x [correct]", packet_checksum);
 197     } else {
 198         checksum_item = proto_tree_add_uint_format(cdp_tree,
 199          hf_cdp_checksum, tvb, offset, 2, packet_checksum,
 200          "Checksum: 0x%04x [incorrect, should be 0x%04x]",
 201          packet_checksum,
 202          in_cksum_shouldbe(packet_checksum, computed_checksum));
 203     }
 204
 205     checksum_tree = proto_item_add_subtree(checksum_item, ett_cdp_checksum);
 206     checksum_item = proto_tree_add_boolean(checksum_tree, hf_cdp_checksum_good,
 207                                            tvb, offset, 2, checksum_good);
 208     PROTO_ITEM_SET_GENERATED(checksum_item);
 209     checksum_item = proto_tree_add_boolean(checksum_tree, hf_cdp_checksum_bad,
 210                                            tvb, offset, 2, checksum_bad);
 211     PROTO_ITEM_SET_GENERATED(checksum_item);
 212
 213     offset += 2;
 214
 215         while (tvb_reported_length_remaining(tvb, offset) != 0) {
 216             type = tvb_get_ntohs(tvb, offset + TLV_TYPE);
 217             length = tvb_get_ntohs(tvb, offset + TLV_LENGTH);
 218             if (length < 4) {
 219                     if(tree) {
 220                     tlvi = proto_tree_add_text(cdp_tree, tvb, offset, 4,
 221                         "TLV with invalid length %u (< 4)",
 222                         length);
 223                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 224                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 225                                 offset + TLV_TYPE, 2, type);
 226                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 227                                 offset + TLV_LENGTH, 2, length);
 228                     }
 229                     offset += 4;
 230                     break;
 231             }
 232
 233             switch (type) {
 234
 235             case TYPE_DEVICE_ID:
 236                 /* Device ID */
 237
 238                 if(check_col(pinfo->cinfo, COL_INFO))
 239                     col_append_fstr(pinfo->cinfo, COL_INFO,
 240                                     "Device ID: %s  ",
 241                                     tvb_format_stringzpad(tvb, offset + 4,
 242                                                           length - 4));
 243
 244                 if(tree){
 245                     tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 246                                 length, "Device ID: %s",
 247                                 tvb_format_stringzpad(tvb, offset + 4, length - 4));
 248                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 249                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 250                                 offset + TLV_TYPE, 2, type);
 251                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 252                                 offset + TLV_LENGTH, 2, length);
 253                     proto_tree_add_text(tlv_tree, tvb, offset + 4,
 254                                 length - 4, "Device ID: %s",
 255                                 tvb_format_stringzpad(tvb, offset + 4, length - 4));
 256                     }
 257                     offset += length;
 258                     break;
 259
 260             case TYPE_PORT_ID:
 261                 real_length = length;
 262                 if (tvb_get_guint8(tvb, offset + real_length) != 0x00) {
 263                     /* The length in the TLV doesn't appear to be the
 264                        length of the TLV, as the byte just past it
 265                        isn't the first byte of a 2-byte big-endian
 266                        small integer; make the length of the TLV the length
 267                        in the TLV, plus 4 bytes for the TLV type and length,
 268                        minus 1 because that's what makes one capture work. */
 269                     real_length = length + 3;
 270                 }
 271
 272                 if(check_col(pinfo->cinfo, COL_INFO))
 273                     col_append_fstr(pinfo->cinfo, COL_INFO,
 274                                     "Port ID: %s  ",
 275                                     tvb_format_stringzpad(tvb, offset + 4,
 276                                                           length - 4));
 277
 278                 if(tree){
 279                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 280                             real_length, "Port ID: %s",
 281                             tvb_format_text(tvb, offset + 4, real_length - 4));
 282                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 283                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 284                             offset + TLV_TYPE, 2, type);
 285                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 286                             offset + TLV_LENGTH, 2, length);
 287                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 288                             real_length - 4,
 289                             "Sent through Interface: %s",
 290                             tvb_format_text(tvb, offset + 4, real_length - 4));
 291                 }
 292                 offset += real_length;
 293                 break;
 294
 295             if(tree){
 296                 case TYPE_ADDRESS:
 297                     /* Addresses */
 298                     tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 299                                 length, "Addresses");
 300                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 301                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 302                                 offset + TLV_TYPE, 2, type);
 303                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 304                                 offset + TLV_LENGTH, 2, length);
 305                     offset += 4;
 306                     length -= 4;
 307                     naddresses = tvb_get_ntohl(tvb, offset);
 308                     proto_tree_add_text(tlv_tree, tvb, offset, 4,
 309                                 "Number of addresses: %u", naddresses);
 310                     offset += 4;
 311                     length -= 4;
 312                     while (naddresses != 0) {
 313                         addr_length = dissect_address_tlv(tvb, offset, length,
 314                                     tlv_tree);
 315                         if (addr_length < 0)
 316                             break;
 317                         offset += addr_length;
 318                         length -= addr_length;
 319
 320                         naddresses--;
 321                     }
 322                     offset += length;
 323                     break;
 324
 325                 case TYPE_CAPABILITIES:
 326                     tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 327                                 length, "Capabilities");
 328                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 329                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 330                                 offset + TLV_TYPE, 2, type);
 331                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 332                                 offset + TLV_LENGTH, 2, length);
 333                     offset += 4;
 334                     length -= 4;
 335                     dissect_capabilities(tvb, offset, length, tlv_tree);
 336                     offset += length;
 337                     break;
 338
 339                 case TYPE_IOS_VERSION:
 340                     tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 341                                 length, "Software Version");
 342                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 343                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 344                                 offset + TLV_TYPE, 2, type);
 345                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 346                                 offset + TLV_LENGTH, 2, length);
 347                     add_multi_line_string_to_tree(tlv_tree, tvb, offset + 4,
 348                                     length - 4, "Software Version: ");
 349                     offset += length;
 350                     break;
 351
 352                 case TYPE_PLATFORM:
 353                     /* ??? platform */
 354                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 355                                 offset, length, "Platform: %s",
 356                                 tvb_format_text(tvb, offset + 4, length - 4));
 357                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 358                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 359                                 offset + TLV_TYPE, 2, type);
 360                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 361                                 offset + TLV_LENGTH, 2, length);
 362                     proto_tree_add_text(tlv_tree, tvb, offset + 4,
 363                                 length - 4, "Platform: %s",
 364                                 tvb_format_text(tvb, offset + 4, length - 4));
 365                     offset += length;
 366                     break;
 367
 368                 case TYPE_IP_PREFIX:
 369                     if (length == 8) {
 370                         /* if length is 8 then this is default gw not prefix */
 371                         tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 372                                 length, "ODR Default gateway: %s",
 373                                 ip_to_str(tvb_get_ptr(tvb, offset+4, 4)));
 374                         tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 375                         proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 376                                 offset + TLV_TYPE, 2, type);
 377                         proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 378                                 offset + TLV_LENGTH, 2, length);
 379                         proto_tree_add_text(tlv_tree, tvb, offset+4, 4,
 380                                     "ODR Default gateway = %s",
 381                                     ip_to_str(tvb_get_ptr(tvb, offset+4, 4)));
 382                         offset += 8;
 383                     } else {
 384                         tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 385                                 length, "IP Prefixes: %d",length/5);
 386
 387                         /* the actual number of prefixes is (length-4)/5
 388                         but if the variable is not a "float" but "integer"
 389                         then length/5=(length-4)/5  :)  */
 390
 391                         tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 392                         proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 393                                 offset + TLV_TYPE, 2, type);
 394                         proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 395                                 offset + TLV_LENGTH, 2, length);
 396                         offset += 4;
 397                         length -= 4;
 398                         while (length > 0) {
 399                             proto_tree_add_text(tlv_tree, tvb, offset, 5,
 400                                     "IP Prefix = %s/%u",
 401                                     ip_to_str(tvb_get_ptr(tvb, offset, 4)),
 402                                     tvb_get_guint8(tvb,offset+4));
 403                             offset += 5;
 404                             length -= 5;
 405                         }
 406                     }
 407                     break;
 408
 409                 case TYPE_PROTOCOL_HELLO:
 410                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 411                                              offset,length, "Protocol Hello: %s",
 412                                              val_to_str(tvb_get_ntohs(tvb, offset+7), type_hello_vals, "Unknown (0x%04x)"));
 413                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 414                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 415                                       offset + TLV_TYPE, 2, type);
 416                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 417                                       offset + TLV_LENGTH, 2, length);
 418                   proto_tree_add_text(tlv_tree, tvb, offset+4, 3,
 419                                       "OUI: 0x%06X (%s)",
 420                                       tvb_get_ntoh24(tvb,offset+4),
 421                                       val_to_str(tvb_get_ntoh24(tvb,offset+4), oui_vals, "Unknown"));
 422                   proto_tree_add_text(tlv_tree, tvb, offset+7, 2,
 423                                       "Protocol ID: 0x%04X (%s)",
 424                                       tvb_get_ntohs(tvb, offset+7),
 425                                       val_to_str(tvb_get_ntohs(tvb, offset+7), type_hello_vals, "Unknown"));
 426                   switch(tvb_get_ntohs(tvb, offset+7)) {
 427
 428                   case TYPE_HELLO_CLUSTER_MGMT:
 429                     /*          proto_tree_add_text(tlv_tree, tvb, offset+9,
 430                                         length - 9, "Cluster Management");
 431                     */
 432                     ip_addr = tvb_get_ipv4(tvb, offset+9);
 433                     proto_tree_add_text(tlv_tree, tvb, offset+9, 4,
 434                                         "Cluster Master IP: %s",ip_to_str((guint8 *)&ip_addr));
 435                     ip_addr = tvb_get_ipv4(tvb, offset+13);
 436                     proto_tree_add_text(tlv_tree, tvb, offset+13, 4,
 437                                         "UNKNOWN (IP?): 0x%08X (%s)",
 438                                           ip_addr, ip_to_str((guint8 *)&ip_addr));
 439                     proto_tree_add_text(tlv_tree, tvb, offset+17, 1,
 440                                         "Version?: 0x%02X",
 441                                         tvb_get_guint8(tvb, offset+17));
 442                     proto_tree_add_text(tlv_tree, tvb, offset+18, 1,
 443                                         "Sub Version?: 0x%02X",
 444                                         tvb_get_guint8(tvb, offset+18));
 445                     proto_tree_add_text(tlv_tree, tvb, offset+19, 1,
 446                                         "Status?: 0x%02X",
 447                                         tvb_get_guint8(tvb, offset+19));
 448                     proto_tree_add_text(tlv_tree, tvb, offset+20, 1,
 449                                         "UNKNOWN: 0x%02X",
 450                                         tvb_get_guint8(tvb, offset+20));
 451                     proto_tree_add_text(tlv_tree, tvb, offset+21, 6,
 452                                         "Cluster Commander MAC: %s",
 453                                         ether_to_str(tvb_get_ptr(tvb, offset+21, 6)));
 454                     proto_tree_add_text(tlv_tree, tvb, offset+27, 6,
 455                                         "Switch's MAC: %s",
 456                                         ether_to_str(tvb_get_ptr(tvb, offset+27, 6)));
 457                     proto_tree_add_text(tlv_tree, tvb, offset+33, 1,
 458                                         "UNKNOWN: 0x%02X",
 459                                         tvb_get_guint8(tvb, offset+33));
 460                     proto_tree_add_text(tlv_tree, tvb, offset+34, 2,
 461                                         "Management VLAN: %d",
 462                                         tvb_get_ntohs(tvb, offset+34));
 463                     break;
 464                   default:
 465                     proto_tree_add_text(tlv_tree, tvb, offset + 9,
 466                                         length - 9, "Unknown");
 467                     break;
 468                   }
 469                   offset += length;
 470                   break;
 471
 472                  case TYPE_VTP_MGMT_DOMAIN:
 473                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 474                                 offset, length, "VTP Management Domain: %s",
 475                                 tvb_format_text(tvb, offset + 4, length - 4));
 476                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 477                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 478                                 offset + TLV_TYPE, 2, type);
 479                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 480                                 offset + TLV_LENGTH, 2, length);
 481                     proto_tree_add_text(tlv_tree, tvb, offset + 4,
 482                                 length - 4, "VTP Management Domain: %s",
 483                                 tvb_format_text(tvb, offset + 4, length - 4));
 484                     offset += length;
 485                     break;
 486
 487                 case TYPE_NATIVE_VLAN:
 488                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 489                                 offset, length, "Native VLAN: %u",
 490                                                tvb_get_ntohs(tvb, offset + 4));
 491                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 492                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 493                                 offset + TLV_TYPE, 2, type);
 494                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 495                                 offset + TLV_LENGTH, 2, length);
 496                     proto_tree_add_text(tlv_tree, tvb, offset + 4,
 497                                 length - 4, "Native VLAN: %u",
 498                                         tvb_get_ntohs(tvb, offset + 4));
 499                     offset += length;
 500                     break;
 501
 502                 case TYPE_DUPLEX:
 503                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 504                                 offset, length, "Duplex: %s",
 505                                                tvb_get_guint8(tvb, offset + 4) ?
 506                                                "Full" : "Half" );
 507                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 508                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 509                                 offset + TLV_TYPE, 2, type);
 510                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 511                                 offset + TLV_LENGTH, 2, length);
 512                     proto_tree_add_text(tlv_tree, tvb, offset + 4,
 513                                 length - 4, "Duplex: %s",
 514                                         tvb_get_guint8(tvb, offset + 4) ?
 515                                         "Full" : "Half" );
 516                     offset += length;
 517                     break;
 518
 519                 case TYPE_VOIP_VLAN_REPLY:
 520                   if (length >= 7) {
 521                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 522                                                offset, length, "VoIP VLAN Reply: %u", tvb_get_ntohs(tvb, offset + 5));
 523                   } else {
 524                     /*
 525                      * XXX - what are these?  I've seen them in some captures;
 526                      * they have a length of 6, and run up to the end of
 527                      * the packet, so if we try to dissect it the same way
 528                      * we dissect the 7-byte ones, we report a malformed
 529                      * frame.
 530                      */
 531                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 532                                                offset, length, "VoIP VLAN Reply");
 533                   }
 534                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 535                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 536                                       offset + TLV_TYPE, 2, type);
 537                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 538                                       offset + TLV_LENGTH, 2, length);
 539                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 540                                       1, "Data");
 541                   if (length >= 7) {
 542                     proto_tree_add_text(tlv_tree, tvb, offset + 5,
 543                                         2, "Voice VLAN: %u",
 544                                         tvb_get_ntohs(tvb, offset + 5));
 545                   }
 546                   offset += length;
 547                   break;
 548
 549                 case TYPE_VOIP_VLAN_QUERY:
 550                   if (length >= 7) {
 551                         tlvi = proto_tree_add_text(cdp_tree, tvb,
 552                                                    offset, length, "VoIP VLAN Query: %u", tvb_get_ntohs(tvb, offset + 5));
 553                   } else {
 554                     /*
 555                      * XXX - what are these?  I've seen them in some captures;
 556                      * they have a length of 6, and run up to the end of
 557                      * the packet, so if we try to dissect it the same way
 558                      * we dissect the 7-byte ones, we report a malformed
 559                      * frame.
 560                      */
 561                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 562                                                offset, length, "VoIP VLAN Query");
 563                   }
 564                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 565                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 566                                       offset + TLV_TYPE, 2, type);
 567                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 568                                       offset + TLV_LENGTH, 2, length);
 569                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 570                                       1, "Data");
 571                   if (length >= 7) {
 572                     proto_tree_add_text(tlv_tree, tvb, offset + 5,
 573                                         2, "Voice VLAN: %u",
 574                                         tvb_get_ntohs(tvb, offset + 5));
 575                   }
 576                   offset += length;
 577                   break;
 578
 579                 case TYPE_POWER:
 580                     tlvi = proto_tree_add_text(cdp_tree, tvb,
 581                                 offset, length, "Power consumption: %u mW",
 582                                                tvb_get_ntohs(tvb, offset + 4));
 583                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 584                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 585                                 offset + TLV_TYPE, 2, type);
 586                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 587                                 offset + TLV_LENGTH, 2, length);
 588                     proto_tree_add_text(tlv_tree, tvb, offset + 4,
 589                                 length - 4, "Power consumption: %u mW",
 590                                         tvb_get_ntohs(tvb, offset + 4));
 591                     offset += length;
 592                     break;
 593
 594                 case TYPE_MTU:
 595                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 596                                              offset, length, "MTU: %u",
 597                                              tvb_get_ntohl(tvb,offset + 4));
 598                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 599                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 600                                       offset + TLV_TYPE, 2, type);
 601                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 602                                       offset + TLV_LENGTH, 2, length);
 603                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 604                                       length - 4, "MTU: %u",
 605                                       tvb_get_ntohl(tvb,offset + 4));
 606                   offset += length;
 607                   break;
 608
 609                 case TYPE_TRUST_BITMAP:
 610                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 611                                              offset, length, "Trust Bitmap: 0x%02X",
 612                                              tvb_get_guint8(tvb, offset + 4));
 613                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 614                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 615                                       offset + TLV_TYPE, 2, type);
 616                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 617                                       offset + TLV_LENGTH, 2, length);
 618                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 619                                       length - 4, "Trust Bitmap: %02x",
 620                                       tvb_get_guint8(tvb, offset + 4));
 621                   offset += length;
 622                   break;
 623
 624                 case TYPE_UNTRUSTED_COS:
 625                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 626                                              offset, length, "Untrusted port CoS: 0x%02X",
 627                                              tvb_get_guint8(tvb, offset + 4));
 628                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 629                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 630                                       offset + TLV_TYPE, 2, type);
 631                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 632                                       offset + TLV_LENGTH, 2, length);
 633                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 634                                       length - 4, "Untrusted port CoS: %02x",
 635                                       tvb_get_guint8(tvb, offset + 4));
 636                   offset += length;
 637                   break;
 638
 639                 case TYPE_SYSTEM_NAME:
 640                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 641                                              offset, length, "System Name: %s",
 642                                              tvb_format_text(tvb, offset + 4, length - 4));
 643                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 644                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 645                                       offset + TLV_TYPE, 2, type);
 646                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 647                                       offset + TLV_LENGTH, 2, length);
 648                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 649                                       length - 4, "System Name: %s",
 650                                       tvb_format_text(tvb, offset + 4, length - 4));
 651                   offset += length;
 652                   break;
 653
 654                 case TYPE_SYSTEM_OID:
 655                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 656                                              offset, length, "System Object Identifier");
 657                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 658                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 659                                       offset + TLV_TYPE, 2, type);
 660                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 661                                       offset + TLV_LENGTH, 2, length);
 662                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 663                                       length - 4, "System Object Identifier: %s",
 664                                       tvb_bytes_to_str(tvb, offset + 4, length - 4));
 665                   offset += length;
 666                   break;
 667
 668                 case TYPE_MANAGEMENT_ADDR:
 669                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 670                                              offset, length, "Management Addresses");
 671                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 672                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 673                                       offset + TLV_TYPE, 2, type);
 674                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 675                                       offset + TLV_LENGTH, 2, length);
 676                   offset += 4;
 677                   length -= 4;
 678                   naddresses = tvb_get_ntohl(tvb, offset);
 679                   proto_tree_add_text(tlv_tree, tvb, offset, 4,
 680                                       "Number of addresses: %u", naddresses);
 681                   offset += 4;
 682                   length -= 4;
 683                   while (naddresses != 0) {
 684                     addr_length = dissect_address_tlv(tvb, offset, length,
 685                                                       tlv_tree);
 686                     if (addr_length < 0)
 687                       break;
 688                     offset += addr_length;
 689                     length -= addr_length;
 690
 691                     naddresses--;
 692                   }
 693                   offset += length;
 694                   break;
 695
 696                 case TYPE_LOCATION:
 697                   tlvi = proto_tree_add_text(cdp_tree, tvb,
 698                                              offset, length, "Location: %s",
 699                                              tvb_format_text(tvb, offset + 5, length - 5));
 700                   tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 701                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 702                                       offset + TLV_TYPE, 2, type);
 703                   proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 704                                       offset + TLV_LENGTH, 2, length);
 705                   proto_tree_add_text(tlv_tree, tvb, offset + 4,
 706                                       1 , "UNKNOWN: 0x%02X",
 707                                       tvb_get_guint8(tvb, offset + 4));
 708                   proto_tree_add_text(tlv_tree, tvb, offset + 5,
 709                                       length - 5, "Location: %s",
 710                                       tvb_format_text(tvb, offset + 5, length - 5));
 711                   offset += length;
 712                   break;
 713                   }
 714
 715                 default:
 716                   tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 717                                 length, "Type: %s, length: %u",
 718                                 val_to_str(type, type_vals, "Unknown (0x%04x)"),
 719                                 length);
 720                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 721                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 722                                 offset + TLV_TYPE, 2, type);
 723                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 724                                 offset + TLV_LENGTH, 2, length);
 725                     if (length > 4) {
 726                             proto_tree_add_text(tlv_tree, tvb, offset + 4,
 727                                             length - 4, "Data");
 728                     } else
 729                             return;
 730                     offset += length;
 731             }
 732         }
 733     call_dissector(data_handle, tvb_new_subset(tvb, offset, -1, -1), pinfo,
 734                         cdp_tree);
 735 }
 736
 737 #define PROTO_TYPE_NLPID        1
 738 #define PROTO_TYPE_IEEE_802_2   2
 739
 740 static const value_string proto_type_vals[] = {
 741         { PROTO_TYPE_NLPID,      "NLPID" },
 742         { PROTO_TYPE_IEEE_802_2, "802.2" },
 743         { 0,                     NULL }
 744 };
 745
 746 static int
 747 dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 748 {
 749     proto_item *ti;
 750     proto_tree *address_tree;
 751     guint8 protocol_type;
 752     guint8 protocol_length;
 753     int nlpid;
 754     const char *protocol_str;
 755     guint16 address_length;
 756     const char *address_type_str;
 757     char *address_str;
 758
 759     if (length < 1)
 760         return -1;
 761     ti = proto_tree_add_text(tree, tvb, offset, length, "Truncated address");
 762     address_tree = proto_item_add_subtree(ti, ett_cdp_address);
 763     protocol_type = tvb_get_guint8(tvb, offset);
 764     proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol type: %s",
 765         val_to_str(protocol_type, proto_type_vals, "Unknown (0x%02x)"));
 766     offset += 1;
 767     length -= 1;
 768
 769     if (length < 1)
 770         return -1;
 771     protocol_length = tvb_get_guint8(tvb, offset);
 772     proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol length: %u",
 773                         protocol_length);
 774     offset += 1;
 775     length -= 1;
 776
 777     if (length < protocol_length) {
 778         if (length != 0) {
 779             proto_tree_add_text(address_tree, tvb, offset, length,
 780               "Protocol: %s (truncated)",
 781               tvb_bytes_to_str(tvb, offset, length));
 782         }
 783         return -1;
 784     }
 785     protocol_str = NULL;
 786     if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
 787         nlpid = tvb_get_guint8(tvb, offset);
 788         protocol_str = val_to_str(nlpid, nlpid_vals, "Unknown (0x%02x)");
 789     } else
 790         nlpid = -1;
 791     if (protocol_str == NULL)
 792         protocol_str = tvb_bytes_to_str(tvb, offset, protocol_length);
 793     proto_tree_add_text(address_tree, tvb, offset, protocol_length,
 794                         "Protocol: %s", protocol_str);
 795     offset += protocol_length;
 796     length -= protocol_length;
 797
 798     if (length < 2)
 799         return -1;
 800     address_length = tvb_get_ntohs(tvb, offset);
 801     proto_tree_add_text(address_tree, tvb, offset, 2, "Address length: %u",
 802                         address_length);
 803     offset += 2;
 804     length -= 2;
 805
 806     if (length < address_length) {
 807         if (length != 0) {
 808             proto_tree_add_text(address_tree, tvb, offset, length,
 809               "Address: %s (truncated)",
 810               tvb_bytes_to_str(tvb, offset, length));
 811         }
 812         return -1;
 813     }
 814     /* XXX - the Cisco document seems to be saying that, for 802.2-format
 815        protocol types, 0xAAAA03 0x000000 0x0800 is IPv6, but 0x0800 is
 816        the Ethernet protocol type for IPv4. */
 817     length = 2 + protocol_length + 2 + address_length;
 818     address_type_str = NULL;
 819     address_str = NULL;
 820     if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
 821         switch (nlpid) {
 822
 823         /* XXX - dissect NLPID_ISO8473_CLNP as OSI CLNP address? */
 824
 825         case NLPID_IP:
 826             if (address_length == 4) {
 827                 /* The address is an IP address. */
 828                 address_type_str = "IP address";
 829                 address_str = ip_to_str(tvb_get_ptr(tvb, offset, 4));
 830             }
 831             break;
 832         }
 833     }
 834     if (address_type_str == NULL)
 835         address_type_str = "Address";
 836     if (address_str == NULL) {
 837         address_str = tvb_bytes_to_str(tvb, offset, address_length);
 838     }
 839     proto_item_set_text(ti, "%s: %s", address_type_str, address_str);
 840     proto_tree_add_text(address_tree, tvb, offset, address_length, "%s: %s",
 841       address_type_str, address_str);
 842     return 2 + protocol_length + 2 + address_length;
 843 }
 844
 845 static void
 846 dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 847 {
 848     proto_item *ti;
 849     proto_tree *capabilities_tree;
 850     guint32 capabilities;
 851
 852     if (length < 4)
 853         return;
 854     capabilities = tvb_get_ntohl(tvb, offset);
 855     ti = proto_tree_add_text(tree, tvb, offset, length, "Capabilities: 0x%08x",
 856         capabilities);
 857     capabilities_tree = proto_item_add_subtree(ti, ett_cdp_capabilities);
 858     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 859         decode_boolean_bitfield(capabilities, 0x01, 4*8,
 860             "Is  a Router",
 861             "Not a Router"));
 862     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 863         decode_boolean_bitfield(capabilities, 0x02, 4*8,
 864             "Is  a Transparent Bridge",
 865             "Not a Transparent Bridge"));
 866     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 867         decode_boolean_bitfield(capabilities, 0x04, 4*8,
 868             "Is  a Source Route Bridge",
 869             "Not a Source Route Bridge"));
 870     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 871         decode_boolean_bitfield(capabilities, 0x08, 4*8,
 872             "Is  a Switch",
 873             "Not a Switch"));
 874     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 875         decode_boolean_bitfield(capabilities, 0x10, 4*8,
 876             "Is  a Host",
 877             "Not a Host"));
 878     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 879         decode_boolean_bitfield(capabilities, 0x20, 4*8,
 880             "Is  IGMP capable",
 881             "Not IGMP capable"));
 882     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 883         decode_boolean_bitfield(capabilities, 0x40, 4*8,
 884             "Is  a Repeater",
 885             "Not a Repeater"));
 886 }
 887
 888 static void
 889 add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
 890   gint len, const gchar *prefix)
 891 {
 892     int prefix_len;
 893     int i;
 894     char blanks[64+1];
 895     gint next;
 896     int line_len;
 897     int data_len;
 898
 899     prefix_len = strlen(prefix);
 900     if (prefix_len > 64)
 901         prefix_len = 64;
 902     for (i = 0; i < prefix_len; i++)
 903         blanks[i] = ' ';
 904     blanks[i] = '\0';
 905     while (len > 0) {
 906         line_len = tvb_find_line_end(tvb, start, len, &next, FALSE);
 907         data_len = next - start;
 908         proto_tree_add_text(tree, tvb, start, data_len, "%s%s", prefix,
 909            tvb_format_stringzpad(tvb, start, line_len));
 910         start += data_len;
 911         len -= data_len;
 912         prefix = blanks;
 913     }
 914 }
 915
 916 void
 917 proto_register_cdp(void)
 918 {
 919     static hf_register_info hf[] = {
 920         { &hf_cdp_version,
 921         { "Version",            "cdp.version",  FT_UINT8, BASE_DEC, NULL, 0x0,
 922           "", HFILL }},
 923
 924         { &hf_cdp_ttl,
 925         { "TTL",                "cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
 926           "", HFILL }},
 927
 928         { &hf_cdp_checksum,
 929         { "Checksum",           "cdp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
 930           "", HFILL }},
 931
 932         { &hf_cdp_checksum_good,
 933           { "Good",       "cdp.checksum_good", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 934             "True: checksum matches packet content; False: doesn't match content or not checked", HFILL }},
 935
 936         { &hf_cdp_checksum_bad,
 937           { "Bad ",       "cdp.checksum_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 938             "True: checksum doesn't match packet content; False: matches content or not checked", HFILL }},
 939
 940         { &hf_cdp_tlvtype,
 941         { "Type",               "cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
 942           "", HFILL }},
 943
 944         { &hf_cdp_tlvlength,
 945         { "Length",             "cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
 946           "", HFILL }}
 947     };
 948     static gint *ett[] = {
 949         &ett_cdp,
 950         &ett_cdp_tlv,
 951         &ett_cdp_address,
 952         &ett_cdp_capabilities,
 953         &ett_cdp_checksum
 954     };
 955
 956     proto_cdp = proto_register_protocol("Cisco Discovery Protocol",
 957                                         "CDP", "cdp");
 958     proto_register_field_array(proto_cdp, hf, array_length(hf));
 959     proto_register_subtree_array(ett, array_length(ett));
 960 }
 961
 962 void
 963 proto_reg_handoff_cdp(void)
 964 {
 965     dissector_handle_t cdp_handle;
 966
 967     data_handle = find_dissector("data");
 968     cdp_handle = create_dissector_handle(dissect_cdp, proto_cdp);
 969     dissector_add("llc.cisco_pid", 0x2000, cdp_handle);
 970     dissector_add("chdlctype", 0x2000, cdp_handle);
 971     dissector_add("ppp.protocol", 0x0207, cdp_handle);
 972 }