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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  24  */
  25
  26 #include "config.h"
  27
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 #include <glib.h>
  32 #include <epan/packet.h>
  33 #include <epan/strutil.h>
  34
  35 #include <epan/oui.h>
  36 #include <epan/nlpid.h>
  37
  38
  39 /*
  40  * See
  41  *
  42  *      http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm#xtocid12
  43  *
  44  * for some information on CDP.
  45  *
  46  * See
  47  *
  48  *      http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a0080094713.shtml#cdp
  49  *
  50  * for some more information on CDP version 2.
  51  */
  52
  53 /* Offsets in TLV structure. */
  54 #define TLV_TYPE        0
  55 #define TLV_LENGTH      2
  56
  57 static int proto_cdp = -1;
  58 static int hf_cdp_version = -1;
  59 static int hf_cdp_checksum = -1;
  60 static int hf_cdp_ttl = -1;
  61 static int hf_cdp_tlvtype = -1;
  62 static int hf_cdp_tlvlength = -1;
  63
  64 static gint ett_cdp = -1;
  65 static gint ett_cdp_tlv = -1;
  66 static gint ett_cdp_address = -1;
  67 static gint ett_cdp_capabilities = -1;
  68
  69 static dissector_handle_t data_handle;
  70
  71 static int
  72 dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
  73 static void
  74 dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
  75 static void
  76 add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
  77   gint len, const gchar *prefix);
  78
  79 #define TYPE_DEVICE_ID          0x0001
  80 #define TYPE_ADDRESS            0x0002
  81 #define TYPE_PORT_ID            0x0003
  82 #define TYPE_CAPABILITIES       0x0004
  83 #define TYPE_IOS_VERSION        0x0005
  84 #define TYPE_PLATFORM           0x0006
  85 #define TYPE_IP_PREFIX          0x0007
  86 #define TYPE_PROTOCOL_HELLO     0x0008 /* Protocol Hello */
  87 #define TYPE_VTP_MGMT_DOMAIN    0x0009 /* VTP Domain, CTPv2 - see second URL */
  88 #define TYPE_NATIVE_VLAN        0x000a /* Native VLAN, CTPv2 - see second URL */
  89 #define TYPE_DUPLEX             0x000b /* Full/Half Duplex - see second URL */
  90 /*                              0x000c */
  91 /*                              0x000d */
  92 #define TYPE_VOIP_VLAN_REPLY    0x000e /* VoIP VLAN reply */
  93 #define TYPE_VOIP_VLAN_QUERY    0x000f /* VoIP VLAN query */
  94 #define TYPE_POWER              0x0010 /* Power consumption */
  95 #define TYPE_MTU                0x0011 /* MTU */
  96 #define TYPE_TRUST_BITMAP       0x0012 /* Trust bitmap */
  97 #define TYPE_UNTRUSTED_COS      0x0013 /* Untrusted port CoS */
  98 #define TYPE_SYSTEM_NAME        0x0014 /* System Name */
  99 #define TYPE_SYSTEM_OID         0x0015 /* System OID */
 100 #define TYPE_MANAGEMENT_ADDR    0x0016 /* Management Address(es) */
 101 #define TYPE_LOCATION           0x0017 /* Location */
 102
 103
 104 static const value_string type_vals[] = {
 105         { TYPE_DEVICE_ID,       "Device ID" },
 106         { TYPE_ADDRESS,         "Addresses" },
 107         { TYPE_PORT_ID,         "Port ID" },
 108         { TYPE_CAPABILITIES,    "Capabilities" },
 109         { TYPE_IOS_VERSION,     "Software version" },
 110         { TYPE_PLATFORM,        "Platform" },
 111         { TYPE_IP_PREFIX,       "IP Prefix/Gateway (used for ODR)" },
 112         { TYPE_PROTOCOL_HELLO,  "Protocol Hello" },
 113         { TYPE_VTP_MGMT_DOMAIN, "VTP Management Domain" },
 114         { TYPE_NATIVE_VLAN,     "Native VLAN" },
 115         { TYPE_DUPLEX,          "Duplex" },
 116         { TYPE_VOIP_VLAN_REPLY, "VoIP VLAN Reply" },
 117         { TYPE_VOIP_VLAN_QUERY, "VoIP VLAN Query" },
 118         { TYPE_POWER,           "Power consumption" },
 119         { TYPE_MTU,             "MTU"},
 120         { TYPE_TRUST_BITMAP,    "Trust Bitmap" },
 121         { TYPE_UNTRUSTED_COS,   "Untrusted Port CoS" },
 122         { TYPE_SYSTEM_NAME,     "System Name" },
 123         { TYPE_SYSTEM_OID,      "System Object ID" },
 124         { TYPE_MANAGEMENT_ADDR, "Management Address" },
 125         { TYPE_LOCATION,        "Location" },
 126         { 0,                    NULL },
 127 };
 128
 129 #define TYPE_HELLO_CLUSTER_MGMT    0x0112
 130
 131 static const value_string type_hello_vals[] = {
 132         { TYPE_HELLO_CLUSTER_MGMT,   "Cluster Management" },
 133         { 0,                    NULL },
 134 };
 135
 136 static void
 137 dissect_cdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 138 {
 139     proto_item *ti;
 140     proto_tree *cdp_tree = NULL;
 141     int offset = 0;
 142     guint16 type;
 143     guint16 length;
 144     proto_item *tlvi;
 145     proto_tree *tlv_tree;
 146     int real_length;
 147     guint32 naddresses;
 148     int addr_length;
 149     guint32 ip_addr;
 150
 151     if (check_col(pinfo->cinfo, COL_PROTOCOL))
 152         col_set_str(pinfo->cinfo, COL_PROTOCOL, "CDP");
 153     if (check_col(pinfo->cinfo, COL_INFO))
 154         col_set_str(pinfo->cinfo, COL_INFO, "Cisco Discovery Protocol");
 155
 156     if (tree){
 157         ti = proto_tree_add_item(tree, proto_cdp, tvb, offset, -1, FALSE);
 158         cdp_tree = proto_item_add_subtree(ti, ett_cdp);
 159
 160         /* CDP header */
 161         proto_tree_add_item(cdp_tree, hf_cdp_version, tvb, offset, 1, FALSE);
 162         offset += 1;
 163         proto_tree_add_uint_format_value(cdp_tree, hf_cdp_ttl, tvb, offset, 1,
 164                                          tvb_get_guint8(tvb, offset),
 165                                          "%u seconds",
 166                                          tvb_get_guint8(tvb, offset));
 167         offset += 1;
 168         proto_tree_add_item(cdp_tree, hf_cdp_checksum, tvb, offset, 2, FALSE);
 169         offset += 2;
 170
 171         while (tvb_reported_length_remaining(tvb, offset) != 0) {
 172             type = tvb_get_ntohs(tvb, offset + TLV_TYPE);
 173             length = tvb_get_ntohs(tvb, offset + TLV_LENGTH);
 174             if (length < 4) {
 175                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset, 4,
 176                     "TLV with invalid length %u (< 4)",
 177                     length);
 178                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 179                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 180                             offset + TLV_TYPE, 2, type);
 181                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 182                             offset + TLV_LENGTH, 2, length);
 183                 offset += 4;
 184                 break;
 185             }
 186
 187             switch (type) {
 188
 189             case TYPE_DEVICE_ID:
 190                 /* Device ID */
 191                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 192                             length, "Device ID: %s",
 193                             tvb_format_stringzpad(tvb, offset + 4, length - 4));
 194                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 195                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 196                             offset + TLV_TYPE, 2, type);
 197                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 198                             offset + TLV_LENGTH, 2, length);
 199                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 200                             length - 4, "Device ID: %s",
 201                             tvb_format_stringzpad(tvb, offset + 4, length - 4));
 202                 offset += length;
 203                 break;
 204
 205             case TYPE_ADDRESS:
 206                 /* Addresses */
 207                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 208                             length, "Addresses");
 209                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 210                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 211                             offset + TLV_TYPE, 2, type);
 212                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 213                             offset + TLV_LENGTH, 2, length);
 214                 offset += 4;
 215                 length -= 4;
 216                 naddresses = tvb_get_ntohl(tvb, offset);
 217                 proto_tree_add_text(tlv_tree, tvb, offset, 4,
 218                             "Number of addresses: %u", naddresses);
 219                 offset += 4;
 220                 length -= 4;
 221                 while (naddresses != 0) {
 222                     addr_length = dissect_address_tlv(tvb, offset, length,
 223                                 tlv_tree);
 224                     if (addr_length < 0)
 225                         break;
 226                     offset += addr_length;
 227                     length -= addr_length;
 228
 229                     naddresses--;
 230                 }
 231                 offset += length;
 232                 break;
 233
 234             case TYPE_PORT_ID:
 235                 real_length = length;
 236                 if (tvb_get_guint8(tvb, offset + real_length) != 0x00) {
 237                     /* The length in the TLV doesn't appear to be the
 238                        length of the TLV, as the byte just past it
 239                        isn't the first byte of a 2-byte big-endian
 240                        small integer; make the length of the TLV the length
 241                        in the TLV, plus 4 bytes for the TLV type and length,
 242                        minus 1 because that's what makes one capture work. */
 243                     real_length = length + 3;
 244                 }
 245                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 246                             real_length, "Port ID: %s",
 247                             tvb_format_text(tvb, offset + 4, real_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                             real_length - 4,
 255                             "Sent through Interface: %s",
 256                             tvb_format_text(tvb, offset + 4, real_length - 4));
 257                 offset += real_length;
 258                 break;
 259
 260             case TYPE_CAPABILITIES:
 261                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 262                             length, "Capabilities");
 263                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 264                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 265                             offset + TLV_TYPE, 2, type);
 266                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 267                             offset + TLV_LENGTH, 2, length);
 268                 offset += 4;
 269                 length -= 4;
 270                 dissect_capabilities(tvb, offset, length, tlv_tree);
 271                 offset += length;
 272                 break;
 273
 274             case TYPE_IOS_VERSION:
 275                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 276                             length, "Software Version");
 277                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 278                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 279                             offset + TLV_TYPE, 2, type);
 280                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 281                             offset + TLV_LENGTH, 2, length);
 282                 add_multi_line_string_to_tree(tlv_tree, tvb, offset + 4,
 283                                 length - 4, "Software Version: ");
 284                 offset += length;
 285                 break;
 286
 287             case TYPE_PLATFORM:
 288                 /* ??? platform */
 289                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 290                             offset, length, "Platform: %s",
 291                             tvb_format_text(tvb, offset + 4, length - 4));
 292                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 293                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 294                             offset + TLV_TYPE, 2, type);
 295                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 296                             offset + TLV_LENGTH, 2, length);
 297                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 298                             length - 4, "Platform: %s",
 299                             tvb_format_text(tvb, offset + 4, length - 4));
 300                 offset += length;
 301                 break;
 302             case TYPE_IP_PREFIX:
 303                 if (length == 8) {
 304                     /* if length is 8 then this is default gw not prefix */
 305                     tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 306                             length, "ODR Default gateway: %s",
 307                             ip_to_str(tvb_get_ptr(tvb, offset+4, 4)));
 308                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 309                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 310                             offset + TLV_TYPE, 2, type);
 311                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 312                             offset + TLV_LENGTH, 2, length);
 313                     proto_tree_add_text(tlv_tree, tvb, offset+4, 4,
 314                                 "ODR Default gateway = %s",
 315                                 ip_to_str(tvb_get_ptr(tvb, offset+4, 4)));
 316                     offset += 8;
 317                 } else {
 318                     tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 319                             length, "IP Prefixes: %d",length/5);
 320
 321                     /* the actual number of prefixes is (length-4)/5
 322                     but if the variable is not a "float" but "integer"
 323                     then length/5=(length-4)/5  :)  */
 324
 325                     tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 326                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 327                             offset + TLV_TYPE, 2, type);
 328                     proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 329                             offset + TLV_LENGTH, 2, length);
 330                     offset += 4;
 331                     length -= 4;
 332                     while (length > 0) {
 333                         proto_tree_add_text(tlv_tree, tvb, offset, 5,
 334                                 "IP Prefix = %s/%u",
 335                                 ip_to_str(tvb_get_ptr(tvb, offset, 4)),
 336                                 tvb_get_guint8(tvb,offset+4));
 337                         offset += 5;
 338                         length -= 5;
 339                     }
 340                 }
 341                 break;
 342             case TYPE_PROTOCOL_HELLO:
 343               tlvi = proto_tree_add_text(cdp_tree, tvb,
 344                                          offset,length, "Protocol Hello: %s",
 345                                          val_to_str(tvb_get_ntohs(tvb, offset+7), type_hello_vals, "Unknown (0x%04x)"));
 346               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 347               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 348                                   offset + TLV_TYPE, 2, type);
 349               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 350                                   offset + TLV_LENGTH, 2, length);
 351               proto_tree_add_text(tlv_tree, tvb, offset+4, 3,
 352                                   "OUI: 0x%06X (%s)",
 353                                   tvb_get_ntoh24(tvb,offset+4),
 354                                   val_to_str(tvb_get_ntoh24(tvb,offset+4), oui_vals, "Unknown"));
 355               proto_tree_add_text(tlv_tree, tvb, offset+7, 2,
 356                                   "Protocol ID: 0x%04X (%s)",
 357                                   tvb_get_ntohs(tvb, offset+7),
 358                                   val_to_str(tvb_get_ntohs(tvb, offset+7), type_hello_vals, "Unknown"));
 359               switch(tvb_get_ntohs(tvb, offset+7)) {
 360               case TYPE_HELLO_CLUSTER_MGMT:
 361                 /*              proto_tree_add_text(tlv_tree, tvb, offset+9,
 362                                     length - 9, "Cluster Management");
 363                 */
 364                 ip_addr = tvb_get_ipv4(tvb, offset+9);
 365                 proto_tree_add_text(tlv_tree, tvb, offset+9, 4,
 366                                     "Cluster Master IP: %s",ip_to_str((guint8 *)&ip_addr));
 367                 ip_addr = tvb_get_ipv4(tvb, offset+13);
 368                 proto_tree_add_text(tlv_tree, tvb, offset+13, 4,
 369                                     "UNKNOWN (IP?): 0x%08X (%s)",
 370                                     ip_addr, ip_to_str((guint8 *)&ip_addr));
 371                 proto_tree_add_text(tlv_tree, tvb, offset+17, 1,
 372                                     "Version?: 0x%02X",
 373                                     tvb_get_guint8(tvb, offset+17));
 374                 proto_tree_add_text(tlv_tree, tvb, offset+18, 1,
 375                                     "Sub Version?: 0x%02X",
 376                                     tvb_get_guint8(tvb, offset+18));
 377                 proto_tree_add_text(tlv_tree, tvb, offset+19, 1,
 378                                     "Status?: 0x%02X",
 379                                     tvb_get_guint8(tvb, offset+19));
 380                 proto_tree_add_text(tlv_tree, tvb, offset+20, 1,
 381                                     "UNKNOWN: 0x%02X",
 382                                     tvb_get_guint8(tvb, offset+20));
 383                 proto_tree_add_text(tlv_tree, tvb, offset+21, 6,
 384                                     "Cluster Commander MAC: %s",
 385                                     ether_to_str(tvb_get_ptr(tvb, offset+21, 6)));
 386                 proto_tree_add_text(tlv_tree, tvb, offset+27, 6,
 387                                     "Switch's MAC: %s",
 388                                     ether_to_str(tvb_get_ptr(tvb, offset+27, 6)));
 389                 proto_tree_add_text(tlv_tree, tvb, offset+33, 1,
 390                                     "UNKNOWN: 0x%02X",
 391                                     tvb_get_guint8(tvb, offset+33));
 392                 proto_tree_add_text(tlv_tree, tvb, offset+34, 2,
 393                                     "Management VLAN: %d",
 394                                     tvb_get_ntohs(tvb, offset+34));
 395                 break;
 396               default:
 397                 proto_tree_add_text(tlv_tree, tvb, offset + 9,
 398                                     length - 9, "Unknown");
 399                 break;
 400               }
 401               offset += length;
 402               break;
 403             case TYPE_VTP_MGMT_DOMAIN:
 404                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 405                             offset, length, "VTP Management Domain: %s",
 406                             tvb_format_text(tvb, offset + 4, length - 4));
 407                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 408                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 409                             offset + TLV_TYPE, 2, type);
 410                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 411                             offset + TLV_LENGTH, 2, length);
 412                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 413                             length - 4, "VTP Management Domain: %s",
 414                             tvb_format_text(tvb, offset + 4, length - 4));
 415                 offset += length;
 416                 break;
 417             case TYPE_NATIVE_VLAN:
 418                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 419                             offset, length, "Native VLAN: %u",
 420                                            tvb_get_ntohs(tvb, offset + 4));
 421                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 422                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 423                             offset + TLV_TYPE, 2, type);
 424                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 425                             offset + TLV_LENGTH, 2, length);
 426                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 427                             length - 4, "Native VLAN: %u",
 428                                     tvb_get_ntohs(tvb, offset + 4));
 429                 offset += length;
 430                 break;
 431             case TYPE_DUPLEX:
 432                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 433                             offset, length, "Duplex: %s",
 434                                            tvb_get_guint8(tvb, offset + 4) ?
 435                                            "Full" : "Half" );
 436                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 437                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 438                             offset + TLV_TYPE, 2, type);
 439                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 440                             offset + TLV_LENGTH, 2, length);
 441                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 442                             length - 4, "Duplex: %s",
 443                                     tvb_get_guint8(tvb, offset + 4) ?
 444                                     "Full" : "Half" );
 445                 offset += length;
 446                 break;
 447             case TYPE_VOIP_VLAN_REPLY:
 448               if (length >= 7) {
 449                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 450                                            offset, length, "VoIP VLAN Reply: %u", tvb_get_ntohs(tvb, offset + 5));
 451               } else {
 452                 /*
 453                  * XXX - what are these?  I've seen them in some captures;
 454                  * they have a length of 6, and run up to the end of
 455                  * the packet, so if we try to dissect it the same way
 456                  * we dissect the 7-byte ones, we report a malformed
 457                  * frame.
 458                  */
 459                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 460                                            offset, length, "VoIP VLAN Reply");
 461               }
 462               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 463               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 464                                   offset + TLV_TYPE, 2, type);
 465               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 466                                   offset + TLV_LENGTH, 2, length);
 467               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 468                                   1, "Data");
 469               if (length >= 7) {
 470                 proto_tree_add_text(tlv_tree, tvb, offset + 5,
 471                                     2, "Voice VLAN: %u",
 472                                     tvb_get_ntohs(tvb, offset + 5));
 473               }
 474               offset += length;
 475               break;
 476             case TYPE_VOIP_VLAN_QUERY:
 477               if (length >= 7) {
 478                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 479                                            offset, length, "VoIP VLAN Query: %u", tvb_get_ntohs(tvb, offset + 5));
 480               } else {
 481                 /*
 482                  * XXX - what are these?  I've seen them in some captures;
 483                  * they have a length of 6, and run up to the end of
 484                  * the packet, so if we try to dissect it the same way
 485                  * we dissect the 7-byte ones, we report a malformed
 486                  * frame.
 487                  */
 488                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 489                                            offset, length, "VoIP VLAN Query");
 490               }
 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                                   1, "Data");
 498               if (length >= 7) {
 499                 proto_tree_add_text(tlv_tree, tvb, offset + 5,
 500                                     2, "Voice VLAN: %u",
 501                                     tvb_get_ntohs(tvb, offset + 5));
 502               }
 503               offset += length;
 504               break;
 505             case TYPE_POWER:
 506                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 507                             offset, length, "Power consumption: %u mW",
 508                                            tvb_get_ntohs(tvb, offset + 4));
 509                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 510                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 511                             offset + TLV_TYPE, 2, type);
 512                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 513                             offset + TLV_LENGTH, 2, length);
 514                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 515                             length - 4, "Power consumption: %u mW",
 516                                     tvb_get_ntohs(tvb, offset + 4));
 517                 offset += length;
 518                 break;
 519             case TYPE_MTU:
 520               tlvi = proto_tree_add_text(cdp_tree, tvb,
 521                                          offset, length, "MTU: %u",
 522                                          tvb_get_ntohl(tvb,offset + 4));
 523               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 524               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 525                                   offset + TLV_TYPE, 2, type);
 526               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 527                                   offset + TLV_LENGTH, 2, length);
 528               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 529                                   length - 4, "MTU: %u",
 530                                   tvb_get_ntohl(tvb,offset + 4));
 531               offset += length;
 532               break;
 533             case TYPE_TRUST_BITMAP:
 534               tlvi = proto_tree_add_text(cdp_tree, tvb,
 535                                          offset, length, "Trust Bitmap: 0x%02X",
 536                                          tvb_get_guint8(tvb, offset + 4));
 537               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 538               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 539                                   offset + TLV_TYPE, 2, type);
 540               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 541                                   offset + TLV_LENGTH, 2, length);
 542               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 543                                   length - 4, "Trust Bitmap: %02x",
 544                                   tvb_get_guint8(tvb, offset + 4));
 545               offset += length;
 546               break;
 547             case TYPE_UNTRUSTED_COS:
 548               tlvi = proto_tree_add_text(cdp_tree, tvb,
 549                                          offset, length, "Untrusted port CoS: 0x%02X",
 550                                          tvb_get_guint8(tvb, offset + 4));
 551               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 552               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 553                                   offset + TLV_TYPE, 2, type);
 554               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 555                                   offset + TLV_LENGTH, 2, length);
 556               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 557                                   length - 4, "Untrusted port CoS: %02x",
 558                                   tvb_get_guint8(tvb, offset + 4));
 559               offset += length;
 560               break;
 561             case TYPE_SYSTEM_NAME:
 562               tlvi = proto_tree_add_text(cdp_tree, tvb,
 563                                          offset, length, "System Name: %s",
 564                                          tvb_format_text(tvb, offset + 4, length - 4));
 565               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 566               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 567                                   offset + TLV_TYPE, 2, type);
 568               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 569                                   offset + TLV_LENGTH, 2, length);
 570               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 571                                   length - 4, "System Name: %s",
 572                                   tvb_format_text(tvb, offset + 4, length - 4));
 573               offset += length;
 574               break;
 575             case TYPE_SYSTEM_OID:
 576               tlvi = proto_tree_add_text(cdp_tree, tvb,
 577                                          offset, length, "System Object Identifier");
 578               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 579               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 580                                   offset + TLV_TYPE, 2, type);
 581               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 582                                   offset + TLV_LENGTH, 2, length);
 583               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 584                                   length - 4, "System Object Identifier: %s",
 585                                   tvb_bytes_to_str(tvb, offset + 4, length - 4));
 586               offset += length;
 587               break;
 588             case TYPE_MANAGEMENT_ADDR:
 589               tlvi = proto_tree_add_text(cdp_tree, tvb,
 590                                          offset, length, "Management Addresses");
 591               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 592               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 593                                   offset + TLV_TYPE, 2, type);
 594               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 595                                   offset + TLV_LENGTH, 2, length);
 596               offset += 4;
 597               length -= 4;
 598               naddresses = tvb_get_ntohl(tvb, offset);
 599               proto_tree_add_text(tlv_tree, tvb, offset, 4,
 600                                   "Number of addresses: %u", naddresses);
 601               offset += 4;
 602               length -= 4;
 603               while (naddresses != 0) {
 604                 addr_length = dissect_address_tlv(tvb, offset, length,
 605                                                   tlv_tree);
 606                 if (addr_length < 0)
 607                   break;
 608                 offset += addr_length;
 609                 length -= addr_length;
 610
 611                 naddresses--;
 612               }
 613               offset += length;
 614               break;
 615             case TYPE_LOCATION:
 616               tlvi = proto_tree_add_text(cdp_tree, tvb,
 617                                          offset, length, "Location: %s",
 618                                          tvb_format_text(tvb, offset + 5, length - 5));
 619               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 620               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 621                                   offset + TLV_TYPE, 2, type);
 622               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 623                                   offset + TLV_LENGTH, 2, length);
 624               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 625                                   1 , "UNKNOWN: 0x%02X",
 626                                   tvb_get_guint8(tvb, offset + 4));
 627               proto_tree_add_text(tlv_tree, tvb, offset + 5,
 628                                   length - 5, "Location: %s",
 629                                   tvb_format_text(tvb, offset + 5, length - 5));
 630               offset += length;
 631               break;
 632             default:
 633                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 634                             length, "Type: %s, length: %u",
 635                             val_to_str(type, type_vals, "Unknown (0x%04x)"),
 636                             length);
 637                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 638                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 639                             offset + TLV_TYPE, 2, type);
 640                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 641                             offset + TLV_LENGTH, 2, length);
 642                 if (length > 4) {
 643                         proto_tree_add_text(tlv_tree, tvb, offset + 4,
 644                                         length - 4, "Data");
 645                 } else
 646                         return;
 647                 offset += length;
 648             }
 649         }
 650         call_dissector(data_handle, tvb_new_subset(tvb, offset, -1, -1), pinfo,
 651                         cdp_tree);
 652     }
 653 }
 654
 655 #define PROTO_TYPE_NLPID        1
 656 #define PROTO_TYPE_IEEE_802_2   2
 657
 658 static const value_string proto_type_vals[] = {
 659         { PROTO_TYPE_NLPID,      "NLPID" },
 660         { PROTO_TYPE_IEEE_802_2, "802.2" },
 661         { 0,                     NULL },
 662 };
 663
 664 static int
 665 dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 666 {
 667     proto_item *ti;
 668     proto_tree *address_tree;
 669     guint8 protocol_type;
 670     guint8 protocol_length;
 671     int nlpid;
 672     const char *protocol_str;
 673     guint16 address_length;
 674     const char *address_type_str;
 675     char *address_str;
 676
 677     if (length < 1)
 678         return -1;
 679     ti = proto_tree_add_text(tree, tvb, offset, length, "Truncated address");
 680     address_tree = proto_item_add_subtree(ti, ett_cdp_address);
 681     protocol_type = tvb_get_guint8(tvb, offset);
 682     proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol type: %s",
 683         val_to_str(protocol_type, proto_type_vals, "Unknown (0x%02x)"));
 684     offset += 1;
 685     length -= 1;
 686
 687     if (length < 1)
 688         return -1;
 689     protocol_length = tvb_get_guint8(tvb, offset);
 690     proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol length: %u",
 691                         protocol_length);
 692     offset += 1;
 693     length -= 1;
 694
 695     if (length < protocol_length) {
 696         if (length != 0) {
 697             proto_tree_add_text(address_tree, tvb, offset, length,
 698               "Protocol: %s (truncated)",
 699               tvb_bytes_to_str(tvb, offset, length));
 700         }
 701         return -1;
 702     }
 703     protocol_str = NULL;
 704     if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
 705         nlpid = tvb_get_guint8(tvb, offset);
 706         protocol_str = val_to_str(nlpid, nlpid_vals, "Unknown (0x%02x)");
 707     } else
 708         nlpid = -1;
 709     if (protocol_str == NULL)
 710         protocol_str = tvb_bytes_to_str(tvb, offset, protocol_length);
 711     proto_tree_add_text(address_tree, tvb, offset, protocol_length,
 712                         "Protocol: %s", protocol_str);
 713     offset += protocol_length;
 714     length -= protocol_length;
 715
 716     if (length < 2)
 717         return -1;
 718     address_length = tvb_get_ntohs(tvb, offset);
 719     proto_tree_add_text(address_tree, tvb, offset, 2, "Address length: %u",
 720                         address_length);
 721     offset += 2;
 722     length -= 2;
 723
 724     if (length < address_length) {
 725         if (length != 0) {
 726             proto_tree_add_text(address_tree, tvb, offset, length,
 727               "Address: %s (truncated)",
 728               tvb_bytes_to_str(tvb, offset, length));
 729         }
 730         return -1;
 731     }
 732     /* XXX - the Cisco document seems to be saying that, for 802.2-format
 733        protocol types, 0xAAAA03 0x000000 0x0800 is IPv6, but 0x0800 is
 734        the Ethernet protocol type for IPv4. */
 735     length = 2 + protocol_length + 2 + address_length;
 736     address_type_str = NULL;
 737     address_str = NULL;
 738     if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
 739         switch (nlpid) {
 740
 741         /* XXX - dissect NLPID_ISO8473_CLNP as OSI CLNP address? */
 742
 743         case NLPID_IP:
 744             if (address_length == 4) {
 745                 /* The address is an IP address. */
 746                 address_type_str = "IP address";
 747                 address_str = ip_to_str(tvb_get_ptr(tvb, offset, 4));
 748             }
 749             break;
 750         }
 751     }
 752     if (address_type_str == NULL)
 753         address_type_str = "Address";
 754     if (address_str == NULL) {
 755         address_str = tvb_bytes_to_str(tvb, offset, address_length);
 756     }
 757     proto_item_set_text(ti, "%s: %s", address_type_str, address_str);
 758     proto_tree_add_text(address_tree, tvb, offset, address_length, "%s: %s",
 759       address_type_str, address_str);
 760     return 2 + protocol_length + 2 + address_length;
 761 }
 762
 763 static void
 764 dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 765 {
 766     proto_item *ti;
 767     proto_tree *capabilities_tree;
 768     guint32 capabilities;
 769
 770     if (length < 4)
 771         return;
 772     capabilities = tvb_get_ntohl(tvb, offset);
 773     ti = proto_tree_add_text(tree, tvb, offset, length, "Capabilities: 0x%08x",
 774         capabilities);
 775     capabilities_tree = proto_item_add_subtree(ti, ett_cdp_capabilities);
 776     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 777         decode_boolean_bitfield(capabilities, 0x01, 4*8,
 778             "Is  a Router",
 779             "Not a Router"));
 780     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 781         decode_boolean_bitfield(capabilities, 0x02, 4*8,
 782             "Is  a Transparent Bridge",
 783             "Not a Transparent Bridge"));
 784     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 785         decode_boolean_bitfield(capabilities, 0x04, 4*8,
 786             "Is  a Source Route Bridge",
 787             "Not a Source Route Bridge"));
 788     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 789         decode_boolean_bitfield(capabilities, 0x08, 4*8,
 790             "Is  a Switch",
 791             "Not a Switch"));
 792     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 793         decode_boolean_bitfield(capabilities, 0x10, 4*8,
 794             "Is  a Host",
 795             "Not a Host"));
 796     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 797         decode_boolean_bitfield(capabilities, 0x20, 4*8,
 798             "Is  IGMP capable",
 799             "Not IGMP capable"));
 800     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 801         decode_boolean_bitfield(capabilities, 0x40, 4*8,
 802             "Is  a Repeater",
 803             "Not a Repeater"));
 804 }
 805
 806 static void
 807 add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
 808   gint len, const gchar *prefix)
 809 {
 810     int prefix_len;
 811     int i;
 812     char blanks[64+1];
 813     gint next;
 814     int line_len;
 815     int data_len;
 816
 817     prefix_len = strlen(prefix);
 818     if (prefix_len > 64)
 819         prefix_len = 64;
 820     for (i = 0; i < prefix_len; i++)
 821         blanks[i] = ' ';
 822     blanks[i] = '\0';
 823     while (len > 0) {
 824         line_len = tvb_find_line_end(tvb, start, len, &next, FALSE);
 825         data_len = next - start;
 826         proto_tree_add_text(tree, tvb, start, data_len, "%s%s", prefix,
 827            tvb_format_stringzpad(tvb, start, line_len));
 828         start += data_len;
 829         len -= data_len;
 830         prefix = blanks;
 831     }
 832 }
 833
 834 void
 835 proto_register_cdp(void)
 836 {
 837     static hf_register_info hf[] = {
 838         { &hf_cdp_version,
 839         { "Version",            "cdp.version",  FT_UINT8, BASE_DEC, NULL, 0x0,
 840           "", HFILL }},
 841
 842         { &hf_cdp_ttl,
 843         { "TTL",                "cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
 844           "", HFILL }},
 845
 846         { &hf_cdp_checksum,
 847         { "Checksum",           "cdp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
 848           "", HFILL }},
 849
 850         { &hf_cdp_tlvtype,
 851         { "Type",               "cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
 852           "", HFILL }},
 853
 854         { &hf_cdp_tlvlength,
 855         { "Length",             "cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
 856           "", HFILL }},
 857     };
 858     static gint *ett[] = {
 859         &ett_cdp,
 860         &ett_cdp_tlv,
 861         &ett_cdp_address,
 862         &ett_cdp_capabilities,
 863     };
 864
 865     proto_cdp = proto_register_protocol("Cisco Discovery Protocol",
 866                                         "CDP", "cdp");
 867     proto_register_field_array(proto_cdp, hf, array_length(hf));
 868     proto_register_subtree_array(ett, array_length(ett));
 869 }
 870
 871 void
 872 proto_reg_handoff_cdp(void)
 873 {
 874     dissector_handle_t cdp_handle;
 875
 876     data_handle = find_dissector("data");
 877     cdp_handle = create_dissector_handle(dissect_cdp, proto_cdp);
 878     dissector_add("llc.cisco_pid", 0x2000, cdp_handle);
 879     dissector_add("chdlctype", 0x2000, cdp_handle);
 880     dissector_add("ppp.protocol", 0x0207, cdp_handle);
 881 }