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: packet-cdp.c,v 1.52 2004/03/13 09:35:41 guy Exp $
   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 (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                             length - 4,
 193                             tvb_get_ptr(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                             length - 4,
 202                             tvb_get_ptr(tvb, offset + 4, length - 4));
 203                 offset += length;
 204                 break;
 205
 206             case TYPE_ADDRESS:
 207                 /* Addresses */
 208                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 209                             length, "Addresses");
 210                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 211                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 212                             offset + TLV_TYPE, 2, type);
 213                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 214                             offset + TLV_LENGTH, 2, length);
 215                 offset += 4;
 216                 length -= 4;
 217                 naddresses = tvb_get_ntohl(tvb, offset);
 218                 proto_tree_add_text(tlv_tree, tvb, offset, 4,
 219                             "Number of addresses: %u", naddresses);
 220                 offset += 4;
 221                 length -= 4;
 222                 while (naddresses != 0) {
 223                     addr_length = dissect_address_tlv(tvb, offset, length,
 224                                 tlv_tree);
 225                     if (addr_length < 0)
 226                         break;
 227                     offset += addr_length;
 228                     length -= addr_length;
 229
 230                     naddresses--;
 231                 }
 232                 offset += length;
 233                 break;
 234
 235             case TYPE_PORT_ID:
 236                 real_length = length;
 237                 if (tvb_get_guint8(tvb, offset + real_length) != 0x00) {
 238                     /* The length in the TLV doesn't appear to be the
 239                        length of the TLV, as the byte just past it
 240                        isn't the first byte of a 2-byte big-endian
 241                        small integer; make the length of the TLV the length
 242                        in the TLV, plus 4 bytes for the TLV type and length,
 243                        minus 1 because that's what makes one capture work. */
 244                     real_length = length + 3;
 245                 }
 246                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 247                             real_length, "Port ID: %.*s",
 248                             real_length - 4,
 249                             tvb_get_ptr(tvb, offset + 4, real_length - 4));
 250                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 251                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 252                             offset + TLV_TYPE, 2, type);
 253                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 254                             offset + TLV_LENGTH, 2, length);
 255                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 256                             real_length - 4,
 257                             "Sent through Interface: %.*s",
 258                             real_length - 4,
 259                             tvb_get_ptr(tvb, offset + 4, real_length - 4));
 260                 offset += real_length;
 261                 break;
 262
 263             case TYPE_CAPABILITIES:
 264                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 265                             length, "Capabilities");
 266                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 267                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 268                             offset + TLV_TYPE, 2, type);
 269                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 270                             offset + TLV_LENGTH, 2, length);
 271                 offset += 4;
 272                 length -= 4;
 273                 dissect_capabilities(tvb, offset, length, tlv_tree);
 274                 offset += length;
 275                 break;
 276
 277             case TYPE_IOS_VERSION:
 278                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 279                             length, "Software Version");
 280                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 281                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 282                             offset + TLV_TYPE, 2, type);
 283                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 284                             offset + TLV_LENGTH, 2, length);
 285                 add_multi_line_string_to_tree(tlv_tree, tvb, offset + 4,
 286                                 length - 4, "Software Version: ");
 287                 offset += length;
 288                 break;
 289
 290             case TYPE_PLATFORM:
 291                 /* ??? platform */
 292                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 293                             offset, length, "Platform: %.*s",
 294                             length - 4,
 295                             tvb_get_ptr(tvb, offset + 4, length - 4));
 296                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 297                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 298                             offset + TLV_TYPE, 2, type);
 299                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 300                             offset + TLV_LENGTH, 2, length);
 301                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 302                             length - 4, "Platform: %.*s",
 303                             length - 4,
 304                             tvb_get_ptr(tvb, offset + 4, length - 4));
 305                 offset += length;
 306                 break;
 307             case TYPE_IP_PREFIX:
 308                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 309                             length, "IP Prefixes: %d",length/5);
 310
 311                             /* the actual number of prefixes is (length-4)/5
 312                             but if the variable is not a "float" but "integer"
 313                             then length/5=(length-4)/5  :)  */
 314
 315                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 316                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 317                             offset + TLV_TYPE, 2, type);
 318                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 319                             offset + TLV_LENGTH, 2, length);
 320                 offset += 4;
 321                 length -= 4;
 322                 while (length > 0) {
 323                         proto_tree_add_text(tlv_tree, tvb, offset, 5,
 324                                 "IP Prefix = %s/%u",
 325                                 ip_to_str(tvb_get_ptr(tvb, offset, 4)),
 326                                 tvb_get_guint8(tvb,offset+4));
 327                         offset += 5;
 328                         length -= 5;
 329                 }
 330                 break;
 331             case TYPE_PROTOCOL_HELLO:
 332               tlvi = proto_tree_add_text(cdp_tree, tvb,
 333                                          offset,length, "Protocol Hello: %s",
 334                                          val_to_str(tvb_get_ntohs(tvb, offset+7), type_hello_vals, "Unknown (0x%04x)"));
 335               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 336               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 337                                   offset + TLV_TYPE, 2, type);
 338               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 339                                   offset + TLV_LENGTH, 2, length);
 340               proto_tree_add_text(tlv_tree, tvb, offset+4, 3,
 341                                   "OUI: 0x%06X (%s)",
 342                                   tvb_get_ntoh24(tvb,offset+4),
 343                                   val_to_str(tvb_get_ntoh24(tvb,offset+4), oui_vals, "Unknown"));
 344               proto_tree_add_text(tlv_tree, tvb, offset+7, 2,
 345                                   "Protocol ID: 0x%04X (%s)",
 346                                   tvb_get_ntohs(tvb, offset+7),
 347                                   val_to_str(tvb_get_ntohs(tvb, offset+7), type_hello_vals, "Unknown"));
 348               switch(tvb_get_ntohs(tvb, offset+7)) {
 349               case TYPE_HELLO_CLUSTER_MGMT:
 350                 /*              proto_tree_add_text(tlv_tree, tvb, offset+9,
 351                                     length - 9, "Cluster Management");
 352                 */
 353                 tvb_memcpy(tvb, (guint8 *)&ip_addr, offset+9, 4);
 354                 proto_tree_add_text(tlv_tree, tvb, offset+9, 4,
 355                                     "Cluster Master IP: %s",ip_to_str((guint8 *)&ip_addr));
 356                 tvb_memcpy(tvb, (guint8 *)&ip_addr, offset+13, 4);
 357                 proto_tree_add_text(tlv_tree, tvb, offset+13, 4,
 358                                     "UNKNOWN (IP?): 0x%08X (%s)",
 359                                     ip_addr, ip_to_str((guint8 *)&ip_addr));
 360                 proto_tree_add_text(tlv_tree, tvb, offset+17, 1,
 361                                     "Version?: 0x%02X",
 362                                     tvb_get_guint8(tvb, offset+17));
 363                 proto_tree_add_text(tlv_tree, tvb, offset+18, 1,
 364                                     "Sub Version?: 0x%02X",
 365                                     tvb_get_guint8(tvb, offset+18));
 366                 proto_tree_add_text(tlv_tree, tvb, offset+19, 1,
 367                                     "Status?: 0x%02X",
 368                                     tvb_get_guint8(tvb, offset+19));
 369                 proto_tree_add_text(tlv_tree, tvb, offset+20, 1,
 370                                     "UNKNOWN: 0x%02X",
 371                                     tvb_get_guint8(tvb, offset+20));
 372                 proto_tree_add_text(tlv_tree, tvb, offset+21, 6,
 373                                     "Cluster Commander MAC: %s",
 374                                     ether_to_str(tvb_get_ptr(tvb, offset+21, 6)));
 375                 proto_tree_add_text(tlv_tree, tvb, offset+27, 6,
 376                                     "Switchs' MAC: %s",
 377                                     ether_to_str(tvb_get_ptr(tvb, offset+27, 6)));
 378                 proto_tree_add_text(tlv_tree, tvb, offset+33, 1,
 379                                     "UNKNOWN: 0x%02X",
 380                                     tvb_get_guint8(tvb, offset+33));
 381                 proto_tree_add_text(tlv_tree, tvb, offset+34, 2,
 382                                     "Management VLAN: %d",
 383                                     tvb_get_ntohs(tvb, offset+34));
 384                 break;
 385               default:
 386                 proto_tree_add_text(tlv_tree, tvb, offset + 9,
 387                                     length - 9, "Unknown");
 388                 break;
 389               }
 390               offset += length;
 391               break;
 392             case TYPE_VTP_MGMT_DOMAIN:
 393                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 394                             offset, length, "VTP Management Domain: %.*s",
 395                             length - 4,
 396                             tvb_get_ptr(tvb, offset + 4, length - 4));
 397                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 398                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 399                             offset + TLV_TYPE, 2, type);
 400                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 401                             offset + TLV_LENGTH, 2, length);
 402                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 403                             length - 4, "VTP Management Domain: %.*s",
 404                             length - 4,
 405                             tvb_get_ptr(tvb, offset + 4, length - 4));
 406                 offset += length;
 407                 break;
 408             case TYPE_NATIVE_VLAN:
 409                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 410                             offset, length, "Native VLAN: %u",
 411                                            tvb_get_ntohs(tvb, offset + 4));
 412                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 413                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 414                             offset + TLV_TYPE, 2, type);
 415                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 416                             offset + TLV_LENGTH, 2, length);
 417                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 418                             length - 4, "Native VLAN: %u",
 419                                     tvb_get_ntohs(tvb, offset + 4));
 420                 offset += length;
 421                 break;
 422             case TYPE_DUPLEX:
 423                 tlvi = proto_tree_add_text(cdp_tree, tvb,
 424                             offset, length, "Duplex: %s",
 425                                            tvb_get_guint8(tvb, offset + 4) ?
 426                                            "Full" : "Half" );
 427                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 428                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 429                             offset + TLV_TYPE, 2, type);
 430                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 431                             offset + TLV_LENGTH, 2, length);
 432                 proto_tree_add_text(tlv_tree, tvb, offset + 4,
 433                             length - 4, "Duplex: %s",
 434                                     tvb_get_guint8(tvb, offset + 4) ?
 435                                     "Full" : "Half" );
 436                 offset += length;
 437                 break;
 438             case TYPE_VOIP_VLAN_REPLY:
 439               tlvi = proto_tree_add_text(cdp_tree, tvb,
 440                                          offset, length, "VoIP VLAN Reply");
 441               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 442               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 443                                   offset + TLV_TYPE, 2, type);
 444               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 445                                   offset + TLV_LENGTH, 2, length);
 446               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 447                                   length - 4, "Data");
 448               offset += length;
 449               break;
 450             case TYPE_VOIP_VLAN_QUERY:
 451               tlvi = proto_tree_add_text(cdp_tree, tvb,
 452                                          offset, length, "VoIP VLAN Query");
 453               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 454               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 455                                   offset + TLV_TYPE, 2, type);
 456               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 457                                   offset + TLV_LENGTH, 2, length);
 458               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 459                                   length - 4, "Data");
 460               offset += length;
 461               break;
 462             case TYPE_MTU:
 463               tlvi = proto_tree_add_text(cdp_tree, tvb,
 464                                          offset, length, "MTU: %u",
 465                                          tvb_get_ntohl(tvb,offset + 4));
 466               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 467               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 468                                   offset + TLV_TYPE, 2, type);
 469               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 470                                   offset + TLV_LENGTH, 2, length);
 471               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 472                                   length - 4, "MTU: %u",
 473                                   tvb_get_ntohl(tvb,offset + 4));
 474               offset += length;
 475               break;
 476             case TYPE_TRUST_BITMAP:
 477               tlvi = proto_tree_add_text(cdp_tree, tvb,
 478                                          offset, length, "Trust Bitmap: 0x%02X",
 479                                          tvb_get_guint8(tvb, offset + 4));
 480               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 481               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 482                                   offset + TLV_TYPE, 2, type);
 483               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 484                                   offset + TLV_LENGTH, 2, length);
 485               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 486                                   length - 4, "Trust Bitmap: %02x",
 487                                   tvb_get_guint8(tvb, offset + 4));
 488               offset += length;
 489               break;
 490             case TYPE_UNTRUSTED_COS:
 491               tlvi = proto_tree_add_text(cdp_tree, tvb,
 492                                          offset, length, "Untrusted port CoS: 0x%02X",
 493                                          tvb_get_guint8(tvb, offset + 4));
 494               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 495               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 496                                   offset + TLV_TYPE, 2, type);
 497               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 498                                   offset + TLV_LENGTH, 2, length);
 499               proto_tree_add_text(tlv_tree, tvb, offset + 4,
 500                                   length - 4, "Untrusted port CoS: %02x",
 501                                   tvb_get_guint8(tvb, offset + 4));
 502               offset += length;
 503               break;
 504             case TYPE_SYSTEM_NAME:
 505               tlvi = proto_tree_add_text(cdp_tree, tvb,
 506                                          offset, length, "System Name: %.*s",
 507                                          length - 4,
 508                                          tvb_get_ptr(tvb, offset + 4, length - 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, "System Name: %.*s",
 516                                   length - 4,
 517                                   tvb_get_ptr(tvb, offset + 4, length - 4));
 518               offset += length;
 519               break;
 520             case TYPE_SYSTEM_OID:
 521               tlvi = proto_tree_add_text(cdp_tree, tvb,
 522                                          offset, length, "System Object Identifier");
 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, "System Object Identifier: %s",
 530                                   tvb_bytes_to_str(tvb, offset + 4, length - 4));
 531               offset += length;
 532               break;
 533             case TYPE_MANAGEMENT_ADDR:
 534               tlvi = proto_tree_add_text(cdp_tree, tvb,
 535                                          offset, length, "Management Addresses");
 536               tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 537               proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 538                                   offset + TLV_TYPE, 2, type);
 539               proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 540                                   offset + TLV_LENGTH, 2, length);
 541               offset += 4;
 542               length -= 4;
 543               naddresses = tvb_get_ntohl(tvb, offset);
 544               proto_tree_add_text(tlv_tree, tvb, offset, 4,
 545                                   "Number of addresses: %u", naddresses);
 546               offset += 4;
 547               length -= 4;
 548               while (naddresses != 0) {
 549                 addr_length = dissect_address_tlv(tvb, offset, length,
 550                                                   tlv_tree);
 551                 if (addr_length < 0)
 552                   break;
 553                 offset += addr_length;
 554                 length -= addr_length;
 555
 556                 naddresses--;
 557               }
 558               offset += length;
 559               break;
 560             case TYPE_LOCATION:
 561               tlvi = proto_tree_add_text(cdp_tree, tvb,
 562                                          offset, length, "Location: %.*s",
 563                                          length - 5,
 564                                          tvb_get_ptr(tvb, offset + 5, length - 5));
 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                                   1 , "UNKNOWN: 0x%02X",
 572                                   tvb_get_guint8(tvb, offset + 4));
 573               proto_tree_add_text(tlv_tree, tvb, offset + 5,
 574                                   length - 5, "Location: %.*s",
 575                                   length - 5,
 576                                   tvb_get_ptr(tvb, offset + 5, length - 5));
 577               offset += length;
 578               break;
 579             default:
 580                 tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
 581                             length, "Type: %s, length: %u",
 582                             val_to_str(type, type_vals, "Unknown (0x%04x)"),
 583                             length);
 584                 tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
 585                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
 586                             offset + TLV_TYPE, 2, type);
 587                 proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
 588                             offset + TLV_LENGTH, 2, length);
 589                 if (length > 4) {
 590                         proto_tree_add_text(tlv_tree, tvb, offset + 4,
 591                                         length - 4, "Data");
 592                 } else
 593                         return;
 594                 offset += length;
 595             }
 596         }
 597         call_dissector(data_handle, tvb_new_subset(tvb, offset, -1, -1), pinfo,
 598                         cdp_tree);
 599     }
 600 }
 601
 602 #define PROTO_TYPE_NLPID        1
 603 #define PROTO_TYPE_IEEE_802_2   2
 604
 605 static const value_string proto_type_vals[] = {
 606         { PROTO_TYPE_NLPID,      "NLPID" },
 607         { PROTO_TYPE_IEEE_802_2, "802.2" },
 608         { 0,                     NULL },
 609 };
 610
 611 static int
 612 dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 613 {
 614     proto_item *ti;
 615     proto_tree *address_tree;
 616     guint8 protocol_type;
 617     guint8 protocol_length;
 618     int nlpid;
 619     char *protocol_str;
 620     guint16 address_length;
 621     char *address_type_str;
 622     char *address_str;
 623
 624     if (length < 1)
 625         return -1;
 626     ti = proto_tree_add_text(tree, tvb, offset, length, "Truncated address");
 627     address_tree = proto_item_add_subtree(ti, ett_cdp_address);
 628     protocol_type = tvb_get_guint8(tvb, offset);
 629     proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol type: %s",
 630         val_to_str(protocol_type, proto_type_vals, "Unknown (0x%02x)"));
 631     offset += 1;
 632     length -= 1;
 633
 634     if (length < 1)
 635         return -1;
 636     protocol_length = tvb_get_guint8(tvb, offset);
 637     proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol length: %u",
 638                         protocol_length);
 639     offset += 1;
 640     length -= 1;
 641
 642     if (length < protocol_length) {
 643         if (length != 0) {
 644             proto_tree_add_text(address_tree, tvb, offset, length,
 645               "Protocol: %s (truncated)",
 646               tvb_bytes_to_str(tvb, offset, length));
 647         }
 648         return -1;
 649     }
 650     protocol_str = NULL;
 651     if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
 652         nlpid = tvb_get_guint8(tvb, offset);
 653         protocol_str = val_to_str(nlpid, nlpid_vals, "Unknown (0x%02x)");
 654     } else
 655         nlpid = -1;
 656     if (protocol_str == NULL)
 657         protocol_str = tvb_bytes_to_str(tvb, offset, protocol_length);
 658     proto_tree_add_text(address_tree, tvb, offset, protocol_length,
 659                         "Protocol: %s", protocol_str);
 660     offset += protocol_length;
 661     length -= protocol_length;
 662
 663     if (length < 2)
 664         return -1;
 665     address_length = tvb_get_ntohs(tvb, offset);
 666     proto_tree_add_text(address_tree, tvb, offset, 2, "Address length: %u",
 667                         address_length);
 668     offset += 2;
 669     length -= 2;
 670
 671     if (length < address_length) {
 672         if (length != 0) {
 673             proto_tree_add_text(address_tree, tvb, offset, length,
 674               "Address: %s (truncated)",
 675               tvb_bytes_to_str(tvb, offset, length));
 676         }
 677         return -1;
 678     }
 679     /* XXX - the Cisco document seems to be saying that, for 802.2-format
 680        protocol types, 0xAAAA03 0x000000 0x0800 is IPv6, but 0x0800 is
 681        the Ethernet protocol type for IPv4. */
 682     length = 2 + protocol_length + 2 + address_length;
 683     address_type_str = NULL;
 684     address_str = NULL;
 685     if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
 686         switch (nlpid) {
 687
 688         /* XXX - dissect NLPID_ISO8473_CLNP as OSI CLNP address? */
 689
 690         case NLPID_IP:
 691             if (address_length == 4) {
 692                 /* The address is an IP address. */
 693                 address_type_str = "IP address";
 694                 address_str = ip_to_str(tvb_get_ptr(tvb, offset, 4));
 695             }
 696             break;
 697         }
 698     }
 699     if (address_type_str == NULL)
 700         address_type_str = "Address";
 701     if (address_str == NULL) {
 702         address_str = tvb_bytes_to_str(tvb, offset, address_length);
 703     }
 704     proto_item_set_text(ti, "%s: %s", address_type_str, address_str);
 705     proto_tree_add_text(address_tree, tvb, offset, address_length, "%s: %s",
 706       address_type_str, address_str);
 707     return 2 + protocol_length + 2 + address_length;
 708 }
 709
 710 static void
 711 dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 712 {
 713     proto_item *ti;
 714     proto_tree *capabilities_tree;
 715     guint32 capabilities;
 716
 717     if (length < 4)
 718         return;
 719     capabilities = tvb_get_ntohl(tvb, offset);
 720     ti = proto_tree_add_text(tree, tvb, offset, length, "Capabilities: 0x%08x",
 721         capabilities);
 722     capabilities_tree = proto_item_add_subtree(ti, ett_cdp_capabilities);
 723     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 724         decode_boolean_bitfield(capabilities, 0x01, 4*8,
 725             "Is  a Router",
 726             "Not a Router"));
 727     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 728         decode_boolean_bitfield(capabilities, 0x02, 4*8,
 729             "Is  a Transparent Bridge",
 730             "Not a Transparent Bridge"));
 731     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 732         decode_boolean_bitfield(capabilities, 0x04, 4*8,
 733             "Is  a Source Route Bridge",
 734             "Not a Source Route Bridge"));
 735     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 736         decode_boolean_bitfield(capabilities, 0x08, 4*8,
 737             "Is  a Switch",
 738             "Not a Switch"));
 739     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 740         decode_boolean_bitfield(capabilities, 0x10, 4*8,
 741             "Is  a Host",
 742             "Not a Host"));
 743     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 744         decode_boolean_bitfield(capabilities, 0x20, 4*8,
 745             "Is  IGMP capable",
 746             "Not IGMP capable"));
 747     proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 748         decode_boolean_bitfield(capabilities, 0x40, 4*8,
 749             "Is  a Repeater",
 750             "Not a Repeater"));
 751 }
 752
 753 static void
 754 add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
 755   gint len, const gchar *prefix)
 756 {
 757     int prefix_len;
 758     int i;
 759     char blanks[64+1];
 760     gint next;
 761     int line_len;
 762     int data_len;
 763
 764     prefix_len = strlen(prefix);
 765     if (prefix_len > 64)
 766         prefix_len = 64;
 767     for (i = 0; i < prefix_len; i++)
 768         blanks[i] = ' ';
 769     blanks[i] = '\0';
 770     while (len > 0) {
 771         line_len = tvb_find_line_end(tvb, start, len, &next, FALSE);
 772         data_len = next - start;
 773         proto_tree_add_text(tree, tvb, start, data_len, "%s%.*s", prefix,
 774            line_len, tvb_get_ptr(tvb, start, line_len));
 775         start += data_len;
 776         len -= data_len;
 777         prefix = blanks;
 778     }
 779 }
 780
 781 void
 782 proto_register_cdp(void)
 783 {
 784     static hf_register_info hf[] = {
 785         { &hf_cdp_version,
 786         { "Version",            "cdp.version",  FT_UINT8, BASE_DEC, NULL, 0x0,
 787           "", HFILL }},
 788
 789         { &hf_cdp_ttl,
 790         { "TTL",                "cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
 791           "", HFILL }},
 792
 793         { &hf_cdp_checksum,
 794         { "Checksum",           "cdp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
 795           "", HFILL }},
 796
 797         { &hf_cdp_tlvtype,
 798         { "Type",               "cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
 799           "", HFILL }},
 800
 801         { &hf_cdp_tlvlength,
 802         { "Length",             "cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
 803           "", HFILL }},
 804     };
 805     static gint *ett[] = {
 806         &ett_cdp,
 807         &ett_cdp_tlv,
 808         &ett_cdp_address,
 809         &ett_cdp_capabilities,
 810     };
 811
 812     proto_cdp = proto_register_protocol("Cisco Discovery Protocol",
 813                                         "CDP", "cdp");
 814     proto_register_field_array(proto_cdp, hf, array_length(hf));
 815     proto_register_subtree_array(ett, array_length(ett));
 816 }
 817
 818 void
 819 proto_reg_handoff_cdp(void)
 820 {
 821     dissector_handle_t cdp_handle;
 822
 823     data_handle = find_dissector("data");
 824     cdp_handle = create_dissector_handle(dissect_cdp, proto_cdp);
 825     dissector_add("llc.cisco_pid", 0x2000, cdp_handle);
 826     dissector_add("chdlctype", 0x2000, cdp_handle);
 827     dissector_add("ppp.protocol", 0x0207, cdp_handle);
 828 }