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