packet-bpdu.c

   1 /* packet-bpdu.c
   2  * Routines for BPDU (Spanning Tree Protocol) disassembly
   3  *
   4  * $Id: packet-bpdu.c,v 1.41 2002/10/08 19:18:57 guy Exp $
   5  *
   6  * Copyright 1999 Christophe Tronche <ch.tronche@computer.org>
   7  *
   8  * Ethereal - Network traffic analyzer
   9  * By Gerald Combs <gerald@ethereal.com>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <glib.h>
  34 #include <epan/packet.h>
  35 #include "llcsaps.h"
  36 #include "ppptypes.h"
  37 #include <epan/resolv.h>
  38
  39 /* Offsets of fields within a BPDU */
  40
  41 #define BPDU_IDENTIFIER          0
  42 #define BPDU_VERSION_IDENTIFIER  2
  43 #define BPDU_TYPE                3
  44 #define BPDU_FLAGS               4
  45 #define BPDU_ROOT_IDENTIFIER     5
  46 #define BPDU_ROOT_PATH_COST     13
  47 #define BPDU_BRIDGE_IDENTIFIER  17
  48 #define BPDU_PORT_IDENTIFIER    25
  49 #define BPDU_MESSAGE_AGE        27
  50 #define BPDU_MAX_AGE            29
  51 #define BPDU_HELLO_TIME         31
  52 #define BPDU_FORWARD_DELAY      33
  53 #define BPDU_VERSION_1_LENGTH   35
  54 #define BPDU_VERSION_3_LENGTH   36
  55 #define BPDU_MST_CONFIG_FORMAT_SELECTOR 38
  56 #define BPDU_MST_CONFIG_NAME 39
  57 #define BPDU_MST_CONFIG_REVISION_LEVEL 71
  58 #define BPDU_MST_CONFIG_DIGEST 73
  59 #define BPDU_CIST_INTERNAL_ROOT_PATH_COST 89
  60 #define BPDU_CIST_BRIDGE_IDENTIFIER 93
  61 #define BPDU_CIST_REMAINING_HOPS        101
  62 #define BPDU_MSTI                       102
  63 #define MSTI_FLAGS                      0
  64 #define MSTI_REGIONAL_ROOT              1
  65 #define MSTI_INTERNAL_ROOT_PATH_COST    9
  66 #define MSTI_BRIDGE_IDENTIFIER_PRIORITY 13
  67 #define MSTI_PORT_IDENTIFIER_PRIORITY   14
  68 #define MSTI_REMAINING_HOPS             15
  69
  70 #define CONF_BPDU_SIZE          35
  71 #define TC_BPDU_SIZE            4
  72 #define RST_BPDU_SIZE           36
  73 #define VERSION_3_STATIC_LENGTH 64
  74 #define MSTI_MESSAGE_SIZE       16
  75
  76 /* Flag bits */
  77
  78 #define BPDU_FLAGS_TCACK                0x80
  79 #define BPDU_FLAGS_AGREEMENT            0x40
  80 #define BPDU_FLAGS_FORWARDING           0x20
  81 #define BPDU_FLAGS_LEARNING             0x10
  82 #define BPDU_FLAGS_PORT_ROLE_MASK       0x0C
  83 #define BPDU_FLAGS_PORT_ROLE_SHIFT      2
  84 #define BPDU_FLAGS_PROPOSAL             0x02
  85 #define BPDU_FLAGS_TC                   0x01
  86
  87 static int proto_bpdu = -1;
  88 static int hf_bpdu_proto_id = -1;
  89 static int hf_bpdu_version_id = -1;
  90 static int hf_bpdu_type = -1;
  91 static int hf_bpdu_flags = -1;
  92 static int hf_bpdu_flags_tcack = -1;
  93 static int hf_bpdu_flags_agreement = -1;
  94 static int hf_bpdu_flags_forwarding = -1;
  95 static int hf_bpdu_flags_learning = -1;
  96 static int hf_bpdu_flags_port_role = -1;
  97 static int hf_bpdu_flags_proposal = -1;
  98 static int hf_bpdu_flags_tc = -1;
  99 static int hf_bpdu_root_mac = -1;
 100 static int hf_bpdu_root_cost = -1;
 101 static int hf_bpdu_bridge_mac = -1;
 102 static int hf_bpdu_port_id = -1;
 103 static int hf_bpdu_msg_age = -1;
 104 static int hf_bpdu_max_age = -1;
 105 static int hf_bpdu_hello_time = -1;
 106 static int hf_bpdu_forward_delay = -1;
 107 static int hf_bpdu_version_1_length = -1;
 108 static int hf_bpdu_version_3_length = -1;
 109 static int hf_bpdu_mst_config_format_selector = -1;
 110 static int hf_bpdu_mst_config_name = -1;
 111 static int hf_bpdu_mst_config_revision_level = -1;
 112 static int hf_bpdu_mst_config_digest = -1;
 113 static int hf_bpdu_cist_internal_root_path_cost = -1;
 114 static int hf_bpdu_cist_bridge_identifier_mac = -1;
 115 static int hf_bpdu_cist_remaining_hops = -1;
 116 static int hf_bpdu_msti_flags = -1;
 117 static int hf_bpdu_msti_regional_root_mac = -1;
 118 static int hf_bpdu_msti_internal_root_path_cost = -1;
 119 static int hf_bpdu_msti_bridge_identifier_priority = -1;
 120 static int hf_bpdu_msti_port_identifier_priority = -1;
 121 static int hf_bpdu_msti_remaining_hops = -1;
 122
 123 static gint ett_bpdu = -1;
 124 static gint ett_bpdu_flags = -1;
 125 static gint ett_mstp = -1;
 126 static gint ett_msti = -1;
 127
 128 static dissector_handle_t gvrp_handle;
 129 static dissector_handle_t gmrp_handle;
 130 static dissector_handle_t data_handle;
 131
 132 static const value_string protocol_id_vals[] = {
 133         { 0, "Spanning Tree Protocol" },
 134         { 0, NULL }
 135 };
 136
 137 #define BPDU_TYPE_CONF                  0x00    /* STP Configuration BPDU */
 138 #define BPDU_TYPE_RST                   0x02    /* RST BPDU (or MST) */
 139 #define BPDU_TYPE_TOPOLOGY_CHANGE       0x80    /* STP TCN (Topology change notify) BPDU */
 140
 141 static const value_string bpdu_type_vals[] = {
 142         { BPDU_TYPE_CONF,            "Configuration" },
 143         { BPDU_TYPE_RST,             "Rapid/Multiple Spanning Tree" },
 144         { BPDU_TYPE_TOPOLOGY_CHANGE, "Topology Change Notification" },
 145         { 0,                         NULL }
 146 };
 147
 148 #define PROTO_VERSION_STP       0
 149 #define PROTO_VERSION_RSTP      2
 150 #define PROTO_VERSION_MSTP      3
 151
 152 static const value_string version_id_vals[] = {
 153         { PROTO_VERSION_STP,    "Spanning Tree" },
 154         { PROTO_VERSION_RSTP,   "Rapid Spanning Tree" },
 155         { PROTO_VERSION_MSTP,   "Multiple Spanning Tree" },
 156         { 0,                    NULL}
 157 };
 158 static const value_string role_vals[] = {
 159         { 1, "Alternate or Backup" },
 160         { 2, "Root" },
 161         { 3, "Designated" },
 162         { 0, NULL }
 163 };
 164
 165 static const char initial_sep[] = " (";
 166 static const char cont_sep[] = ", ";
 167
 168 #define APPEND_BOOLEAN_FLAG(flag, item, string) \
 169         if(flag){                                                       \
 170                 if(item)                                                \
 171                         proto_item_append_text(item, string, sep);      \
 172                 sep = cont_sep;                                         \
 173         }
 174
 175 static void
 176 dissect_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 177 {
 178       guint16 protocol_identifier;
 179       guint8  protocol_version_identifier;
 180       guint8  bpdu_type;
 181       guint8  flags;
 182       guint16 root_identifier_bridge_priority;
 183       const guint8  *root_identifier_mac;
 184       gchar   *root_identifier_mac_str;
 185       guint32 root_path_cost;
 186       guint16 bridge_identifier_bridge_priority;
 187       const guint8  *bridge_identifier_mac;
 188       gchar   *bridge_identifier_mac_str;
 189       guint16 port_identifier;
 190       double message_age;
 191       double max_age;
 192       double hello_time;
 193       double forward_delay;
 194       guint16 version_3_length;
 195       guint32 cist_internal_root_path_cost;
 196       guint8 mst_config_format_selector;
 197       guint16 cist_bridge_identifier_bridge_priority;
 198       const guint8  *cist_bridge_identifier_mac;
 199       gchar   *cist_bridge_identifier_mac_str;
 200       const guint8 *mst_config_name;
 201       guint16 mst_config_revision_level;
 202       guint8 cist_remaining_hops, msti_remaining_hops;
 203       guint32 msti_internal_root_path_cost;
 204       guint32 msti_regional_root_mstid, msti_regional_root_priority;
 205       const guint8  *msti_regional_root_mac;
 206       gchar   *msti_regional_root_mac_str;
 207       guint8 msti_bridge_identifier_priority, msti_port_identifier_priority;
 208       int       length, offset, msti;
 209
 210       proto_tree *bpdu_tree;
 211       proto_tree *mstp_tree, *msti_tree;
 212       proto_item *bpdu_item;
 213       proto_item *mstp_item, *msti_item;
 214       proto_tree *flags_tree;
 215       proto_item *flags_item;
 216       guint8    rstp_bpdu, mstp_bpdu=0;
 217       const char *sep;
 218
 219       /* GARP application frames require special interpretation of the
 220          destination address field; otherwise, they will be mistaken as
 221          BPDU frames.
 222          Fortunately, they can be recognized by checking the first 6 octets
 223          of the destination address, which are in the range from
 224          01-80-C2-00-00-20 to 01-80-C2-00-00-2F.
 225
 226          Yes - we *do* need to check the destination address type;
 227          on Linux cooked captures, there *is* no destination address,
 228          so it's AT_NONE. */
 229       if (pinfo->dl_dst.type == AT_ETHER &&
 230           pinfo->dl_dst.data[0] == 0x01 && pinfo->dl_dst.data[1] == 0x80 &&
 231           pinfo->dl_dst.data[2] == 0xC2 && pinfo->dl_dst.data[3] == 0x00 &&
 232           pinfo->dl_dst.data[4] == 0x00 && ((pinfo->dl_dst.data[5] & 0x20) == 0x20)) {
 233
 234             protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
 235
 236             switch (pinfo->dl_dst.data[5]) {
 237
 238             case 0x20:
 239                    /* for GMRP */
 240                   call_dissector(gmrp_handle, tvb, pinfo, tree);
 241                   return;
 242
 243             case 0x21:
 244                   /* for GVRP */
 245                   call_dissector(gvrp_handle, tvb, pinfo, tree);
 246                   return;
 247             }
 248
 249             pinfo->current_proto = "GARP";
 250
 251             if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 252                     col_set_str(pinfo->cinfo, COL_PROTOCOL, "GARP");
 253                     /* Generic Attribute Registration Protocol */
 254             }
 255
 256             if (check_col(pinfo->cinfo, COL_INFO)) {
 257                     col_add_fstr(pinfo->cinfo, COL_INFO,
 258                         "Unknown GARP application (0x%02X)",
 259                         pinfo->dl_dst.data[5]);
 260             }
 261
 262             return;
 263       }
 264
 265       if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 266             col_set_str(pinfo->cinfo, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
 267       }
 268       if (check_col(pinfo->cinfo, COL_INFO)) {
 269             col_clear(pinfo->cinfo, COL_INFO);
 270       }
 271
 272       bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
 273       switch (bpdu_type) {
 274
 275       case BPDU_TYPE_CONF:
 276       case BPDU_TYPE_RST:
 277             protocol_version_identifier = tvb_get_guint8(tvb, BPDU_VERSION_IDENTIFIER);
 278             flags = tvb_get_guint8(tvb, BPDU_FLAGS);
 279             root_identifier_bridge_priority = tvb_get_ntohs(tvb,BPDU_ROOT_IDENTIFIER);
 280             root_identifier_mac = tvb_get_ptr(tvb, BPDU_ROOT_IDENTIFIER + 2, 6);
 281             root_identifier_mac_str = ether_to_str(root_identifier_mac);
 282             root_path_cost = tvb_get_ntohl(tvb, BPDU_ROOT_PATH_COST);
 283             port_identifier = tvb_get_ntohs(tvb, BPDU_PORT_IDENTIFIER);
 284             break;
 285
 286       default:
 287             /* Squelch GCC complaints. */
 288             protocol_version_identifier = 0;
 289             flags = 0;
 290             root_identifier_bridge_priority = 0;
 291             root_identifier_mac = NULL;
 292             root_identifier_mac_str = NULL;
 293             root_path_cost = 0;
 294             port_identifier = 0;
 295             break;
 296       }
 297
 298       if (check_col(pinfo->cinfo, COL_INFO)) {
 299             switch (bpdu_type) {
 300
 301             case BPDU_TYPE_CONF:
 302                   col_add_fstr(pinfo->cinfo, COL_INFO, "Conf. %sRoot = %d/%s  Cost = %d  Port = 0x%04x",
 303                                flags & 0x1 ? "TC + " : "",
 304                                root_identifier_bridge_priority, root_identifier_mac_str, root_path_cost,
 305                                port_identifier);
 306                   break;
 307
 308             case BPDU_TYPE_TOPOLOGY_CHANGE:
 309                   col_add_fstr(pinfo->cinfo, COL_INFO, "Topology Change Notification");
 310                   break;
 311
 312             case BPDU_TYPE_RST:
 313                   col_add_fstr(pinfo->cinfo, COL_INFO, "%cST. %sRoot = %d/%s  Cost = %d  Port = 0x%04x",
 314                                protocol_version_identifier == 3 ? 'M':'R',
 315                                flags & 0x1 ? "TC + " : "",
 316                                root_identifier_bridge_priority, root_identifier_mac_str, root_path_cost,
 317                                port_identifier);
 318                   break;
 319
 320             default:
 321                   col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown BPDU type (%u)",
 322                                bpdu_type);
 323                   break;
 324             }
 325       }
 326
 327       switch (bpdu_type) {
 328
 329       case BPDU_TYPE_CONF:
 330         set_actual_length(tvb, CONF_BPDU_SIZE);
 331         break;
 332
 333       case BPDU_TYPE_TOPOLOGY_CHANGE:
 334         set_actual_length(tvb, TC_BPDU_SIZE);
 335         break;
 336
 337       case BPDU_TYPE_RST:
 338         if (protocol_version_identifier == 3) {
 339             version_3_length = tvb_get_ntohs(tvb, BPDU_VERSION_3_LENGTH);
 340             set_actual_length(tvb, RST_BPDU_SIZE + 2 + version_3_length);
 341         } else
 342             set_actual_length(tvb, RST_BPDU_SIZE);
 343         break;
 344       }
 345
 346       if (tree) {
 347             bpdu_item = proto_tree_add_protocol_format(tree, proto_bpdu, tvb,
 348                                 0, -1, "Spanning Tree Protocol");
 349             bpdu_tree = proto_item_add_subtree(bpdu_item, ett_bpdu);
 350
 351             protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
 352             proto_tree_add_uint(bpdu_tree, hf_bpdu_proto_id, tvb,
 353                                 BPDU_IDENTIFIER, 2, protocol_identifier);
 354
 355             proto_tree_add_uint(bpdu_tree, hf_bpdu_version_id, tvb,
 356                                 BPDU_VERSION_IDENTIFIER, 1,
 357                                 protocol_version_identifier);
 358             switch (protocol_version_identifier) {
 359               case 0:
 360                 break;
 361               case 2:
 362               case 3:
 363                 break;
 364               default:
 365                   proto_tree_add_text(bpdu_tree, tvb, BPDU_VERSION_IDENTIFIER, 1,
 366                   "   (Warning: this version of Ethereal only knows about versions 0, 2 & 3)");
 367                 break;
 368             }
 369             proto_tree_add_uint(bpdu_tree, hf_bpdu_type, tvb,
 370                                        BPDU_TYPE, 1,
 371                                        bpdu_type);
 372
 373             if (bpdu_type != BPDU_TYPE_CONF && bpdu_type != BPDU_TYPE_RST) {
 374               call_dissector(data_handle,
 375                              tvb_new_subset(tvb, BPDU_TYPE + 1, -1, -1),
 376                              pinfo, tree);
 377               return;
 378             }
 379
 380             rstp_bpdu = (bpdu_type == BPDU_TYPE_RST);
 381             if (rstp_bpdu) mstp_bpdu = (protocol_version_identifier == 3);
 382
 383             bridge_identifier_bridge_priority = tvb_get_ntohs(tvb, BPDU_BRIDGE_IDENTIFIER);
 384             bridge_identifier_mac = tvb_get_ptr(tvb, BPDU_BRIDGE_IDENTIFIER + 2, 6);
 385             bridge_identifier_mac_str = ether_to_str(bridge_identifier_mac);
 386
 387             flags_item = proto_tree_add_uint(bpdu_tree, hf_bpdu_flags, tvb,
 388                                 BPDU_FLAGS, 1, flags);
 389             flags_tree = proto_item_add_subtree(flags_item, ett_bpdu_flags);
 390             sep = initial_sep;
 391             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TCACK, flags_item,
 392                                 "%sTopology Change Acknowledgment");
 393             proto_tree_add_boolean(flags_tree, hf_bpdu_flags_tcack, tvb,
 394                                 BPDU_FLAGS, 1, flags);
 395             if (rstp_bpdu) {
 396               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_AGREEMENT, flags_item,
 397                                   "%sAgreement");
 398               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_agreement, tvb,
 399                                   BPDU_FLAGS, 1, flags);
 400               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_FORWARDING, flags_item,
 401                                   "%sForwarding");
 402               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_forwarding, tvb,
 403                                   BPDU_FLAGS, 1, flags);
 404               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_LEARNING, flags_item,
 405                                   "%sLearning");
 406               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_learning, tvb,
 407                                   BPDU_FLAGS, 1, flags);
 408               if (flags_item) {
 409                 guint8 port_role;
 410
 411                 port_role = (flags & BPDU_FLAGS_PORT_ROLE_MASK) >> BPDU_FLAGS_PORT_ROLE_SHIFT;
 412                 proto_item_append_text(flags_item, "%sPort Role: %s", sep,
 413                                        val_to_str(port_role, role_vals,
 414                                                   "Unknown (%u)"));
 415               }
 416               sep = cont_sep;
 417               proto_tree_add_uint(flags_tree, hf_bpdu_flags_port_role, tvb,
 418                                   BPDU_FLAGS, 1, flags);
 419               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_PROPOSAL, flags_item,
 420                                   "%sProposal");
 421               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_proposal, tvb,
 422                                   BPDU_FLAGS, 1, flags);
 423             }
 424             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TC, flags_item,
 425                                 "%sTopology Change");
 426             proto_tree_add_boolean(flags_tree, hf_bpdu_flags_tc, tvb,
 427                                 BPDU_FLAGS, 1, flags);
 428             if (sep != initial_sep) {
 429               /* We put something in; put in the terminating ")" */
 430               proto_item_append_text(flags_item, ")");
 431             }
 432
 433             proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_root_mac, tvb,
 434                                        BPDU_ROOT_IDENTIFIER + 2, 6,
 435                                        root_identifier_mac);
 436             proto_tree_add_text(bpdu_tree, tvb,
 437                                 BPDU_ROOT_IDENTIFIER, 8,
 438                                 "Root Identifier: %d / %s",
 439                                 root_identifier_bridge_priority,
 440                                 root_identifier_mac_str);
 441             proto_tree_add_uint(bpdu_tree, hf_bpdu_root_cost, tvb,
 442                                 BPDU_ROOT_PATH_COST, 4,
 443                                 root_path_cost);
 444             proto_tree_add_text(bpdu_tree, tvb,
 445                                 BPDU_BRIDGE_IDENTIFIER, 8,
 446                                 "Bridge Identifier: %d / %s",
 447                                 bridge_identifier_bridge_priority,
 448                                 bridge_identifier_mac_str);
 449             proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_bridge_mac, tvb,
 450                                        BPDU_BRIDGE_IDENTIFIER + 2, 6,
 451                                        bridge_identifier_mac);
 452             proto_tree_add_uint(bpdu_tree, hf_bpdu_port_id, tvb,
 453                                 BPDU_PORT_IDENTIFIER, 2,
 454                                 port_identifier);
 455             message_age = tvb_get_ntohs(tvb, BPDU_MESSAGE_AGE) / 256.0;
 456             proto_tree_add_double(bpdu_tree, hf_bpdu_msg_age, tvb,
 457                                 BPDU_MESSAGE_AGE, 2,
 458                                 message_age);
 459             max_age = tvb_get_ntohs(tvb, BPDU_MAX_AGE) / 256.0;
 460             proto_tree_add_double(bpdu_tree, hf_bpdu_max_age, tvb,
 461                                 BPDU_MAX_AGE, 2,
 462                                 max_age);
 463             hello_time = tvb_get_ntohs(tvb, BPDU_HELLO_TIME) / 256.0;
 464             proto_tree_add_double(bpdu_tree, hf_bpdu_hello_time, tvb,
 465                                 BPDU_HELLO_TIME, 2,
 466                                 hello_time);
 467             forward_delay = tvb_get_ntohs(tvb, BPDU_FORWARD_DELAY) / 256.0;
 468             proto_tree_add_double(bpdu_tree, hf_bpdu_forward_delay, tvb,
 469                                 BPDU_FORWARD_DELAY, 2,
 470                                 forward_delay);
 471             if (rstp_bpdu) {
 472               proto_tree_add_item(bpdu_tree, hf_bpdu_version_1_length, tvb,
 473                                 BPDU_VERSION_1_LENGTH, 1, FALSE);
 474             }
 475             if (mstp_bpdu) {
 476                 version_3_length = tvb_get_ntohs(tvb, BPDU_VERSION_3_LENGTH);
 477
 478                 mstp_item = proto_tree_add_uint(bpdu_tree, hf_bpdu_version_3_length, tvb,
 479                         BPDU_VERSION_3_LENGTH, 2, version_3_length);
 480                 mstp_tree = proto_item_add_subtree(mstp_item, ett_mstp);
 481
 482
 483                 mst_config_format_selector = tvb_get_guint8(tvb, BPDU_MST_CONFIG_FORMAT_SELECTOR);
 484                 proto_tree_add_uint(mstp_tree, hf_bpdu_mst_config_format_selector, tvb,
 485                         BPDU_MST_CONFIG_FORMAT_SELECTOR, 1, mst_config_format_selector);
 486                 mst_config_name =  tvb_get_ptr (tvb, BPDU_MST_CONFIG_NAME, 32);
 487                 proto_tree_add_string(mstp_tree, hf_bpdu_mst_config_name, tvb, BPDU_MST_CONFIG_NAME, 32, mst_config_name);
 488
 489                 mst_config_revision_level = tvb_get_ntohs(tvb, BPDU_MST_CONFIG_REVISION_LEVEL);
 490                 proto_tree_add_uint(mstp_tree, hf_bpdu_mst_config_revision_level, tvb,
 491                         BPDU_MST_CONFIG_REVISION_LEVEL, 2, mst_config_revision_level);
 492                 proto_tree_add_bytes(mstp_tree, hf_bpdu_mst_config_digest, tvb,
 493                         BPDU_MST_CONFIG_DIGEST, 16, tvb_get_ptr(tvb, BPDU_MST_CONFIG_DIGEST, 16));
 494
 495                 cist_internal_root_path_cost = tvb_get_ntohl(tvb, BPDU_CIST_INTERNAL_ROOT_PATH_COST);
 496                 proto_tree_add_uint(mstp_tree, hf_bpdu_cist_internal_root_path_cost, tvb,
 497                         BPDU_CIST_INTERNAL_ROOT_PATH_COST, 4, cist_internal_root_path_cost);
 498
 499                 cist_bridge_identifier_bridge_priority = tvb_get_ntohs(tvb,BPDU_CIST_BRIDGE_IDENTIFIER);
 500                 cist_bridge_identifier_mac = tvb_get_ptr(tvb, BPDU_CIST_BRIDGE_IDENTIFIER + 2, 6);
 501                 cist_bridge_identifier_mac_str = ether_to_str(cist_bridge_identifier_mac);
 502                 proto_tree_add_text(mstp_tree, tvb, BPDU_CIST_BRIDGE_IDENTIFIER, 8,
 503                                 "CIST Bridge Identifier: %d / %s",
 504                                 cist_bridge_identifier_bridge_priority,
 505                                 cist_bridge_identifier_mac_str);
 506                 proto_tree_add_ether_hidden(mstp_tree, hf_bpdu_cist_bridge_identifier_mac, tvb,
 507                                        BPDU_CIST_BRIDGE_IDENTIFIER + 2, 6,
 508                                        cist_bridge_identifier_mac);
 509
 510                 cist_remaining_hops = tvb_get_guint8(tvb, BPDU_CIST_REMAINING_HOPS);
 511                 proto_tree_add_uint(mstp_tree, hf_bpdu_cist_remaining_hops, tvb,
 512                         BPDU_CIST_REMAINING_HOPS, 1, cist_remaining_hops);
 513
 514         /* MSTI messages */
 515                 length = version_3_length - VERSION_3_STATIC_LENGTH;
 516                 offset = BPDU_MSTI;
 517                 msti = 1;
 518                 while (length >= MSTI_MESSAGE_SIZE) {
 519                     msti_regional_root_mstid = tvb_get_guint8(tvb,  offset+ MSTI_REGIONAL_ROOT);
 520                     msti_regional_root_priority = (msti_regional_root_mstid &0xf0) << 8;
 521                     msti_regional_root_mstid = ((msti_regional_root_mstid & 0x0f) << 8) +
 522                                 tvb_get_guint8(tvb,  offset+ MSTI_REGIONAL_ROOT+1);;
 523                     msti_regional_root_mac = tvb_get_ptr(tvb, offset+ MSTI_REGIONAL_ROOT + 2, 6);
 524                     msti_regional_root_mac_str = ether_to_str(msti_regional_root_mac);
 525
 526                     msti_item = proto_tree_add_text(mstp_tree, tvb, offset, 16,
 527                         "MSTID %d, Regional Root Identifier %d / %s",
 528                         msti_regional_root_mstid, msti_regional_root_priority,
 529                         msti_regional_root_mac_str);
 530                     msti_tree = proto_item_add_subtree(msti_item, ett_msti);
 531
 532                     /* flags */
 533                     flags_item = proto_tree_add_uint(msti_tree, hf_bpdu_msti_flags, tvb,
 534                         offset+MSTI_FLAGS, 1, flags);
 535
 536                     sep = initial_sep;
 537                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TCACK, flags_item, "%sMaster");
 538                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_AGREEMENT, flags_item, "%sAgreement");
 539                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_FORWARDING, flags_item, "%sForwarding");
 540                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_LEARNING, flags_item, "%sLearning");
 541                     if (flags_item) {
 542                         guint8 port_role;
 543                         port_role = (flags & BPDU_FLAGS_PORT_ROLE_MASK) >> BPDU_FLAGS_PORT_ROLE_SHIFT;
 544                         proto_item_append_text(flags_item, "%sPort Role: %s", sep,
 545                                        val_to_str(port_role, role_vals, "Unknown (%u)"));
 546                     }
 547                     sep = cont_sep;
 548                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_PROPOSAL, flags_item, "%sProposal");
 549                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TC, flags_item, "%sTopology Change");
 550                     if (sep != initial_sep) {         /* We put something in; put in the terminating ")" */
 551                         proto_item_append_text(flags_item, ")");
 552                     }
 553
 554                     /* pri, MSTID, Regional root */
 555                     proto_tree_add_ether_hidden(msti_tree, hf_bpdu_msti_regional_root_mac, tvb,
 556                                        offset + MSTI_REGIONAL_ROOT + 2, 6,
 557                                        msti_regional_root_mac);
 558                     proto_tree_add_text(msti_tree, tvb, offset + MSTI_REGIONAL_ROOT, 8,
 559                                 "MSTID %d, priority %d Root Identifier %s",
 560                                 msti_regional_root_mstid, msti_regional_root_priority,
 561                                 msti_regional_root_mac_str);
 562
 563
 564                     msti_internal_root_path_cost = tvb_get_ntohs(tvb, offset+MSTI_INTERNAL_ROOT_PATH_COST);
 565                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_internal_root_path_cost, tvb,
 566                         offset+MSTI_INTERNAL_ROOT_PATH_COST, 4, msti_internal_root_path_cost);
 567
 568                     msti_bridge_identifier_priority = tvb_get_guint8(tvb, offset+MSTI_BRIDGE_IDENTIFIER_PRIORITY) >> 4;
 569                     msti_port_identifier_priority = tvb_get_guint8(tvb, offset+MSTI_PORT_IDENTIFIER_PRIORITY) >> 4;
 570
 571                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_bridge_identifier_priority, tvb,
 572                         offset+MSTI_BRIDGE_IDENTIFIER_PRIORITY, 1, msti_bridge_identifier_priority);
 573                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_port_identifier_priority, tvb,
 574                         offset+MSTI_PORT_IDENTIFIER_PRIORITY, 1, msti_port_identifier_priority);
 575
 576                     msti_remaining_hops = tvb_get_guint8(tvb, offset+MSTI_REMAINING_HOPS);
 577                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_remaining_hops, tvb,
 578                         offset + MSTI_REMAINING_HOPS, 1, msti_remaining_hops);
 579
 580                     length -= MSTI_MESSAGE_SIZE;
 581                     offset += MSTI_MESSAGE_SIZE;
 582                     msti++;
 583                 }
 584
 585             }
 586       }
 587 }
 588
 589 static const true_false_string yesno = {
 590         "Yes",
 591         "No"
 592 };
 593
 594 void
 595 proto_register_bpdu(void)
 596 {
 597
 598   static hf_register_info hf[] = {
 599     { &hf_bpdu_proto_id,
 600       { "Protocol Identifier",          "stp.protocol",
 601         FT_UINT16,      BASE_HEX,       VALS(&protocol_id_vals), 0x0,
 602         "", HFILL }},
 603     { &hf_bpdu_version_id,
 604       { "Protocol Version Identifier",  "stp.version",
 605         FT_UINT8,       BASE_DEC,       VALS(&version_id_vals), 0x0,
 606         "", HFILL }},
 607     { &hf_bpdu_type,
 608       { "BPDU Type",                    "stp.type",
 609         FT_UINT8,       BASE_HEX,       VALS(&bpdu_type_vals),  0x0,
 610         "", HFILL }},
 611     { &hf_bpdu_flags,
 612       { "BPDU flags",                   "stp.flags",
 613         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 614         "", HFILL }},
 615     { &hf_bpdu_flags_tcack,
 616       { "Topology Change Acknowledgment",  "stp.flags.tcack",
 617         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TCACK,
 618         "", HFILL }},
 619     { &hf_bpdu_flags_agreement,
 620       { "Agreement",                    "stp.flags.agreement",
 621         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_AGREEMENT,
 622         "", HFILL }},
 623     { &hf_bpdu_flags_forwarding,
 624       { "Forwarding",                   "stp.flags.forwarding",
 625         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_FORWARDING,
 626         "", HFILL }},
 627     { &hf_bpdu_flags_learning,
 628       { "Learning",                     "stp.flags.learning",
 629         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_LEARNING,
 630         "", HFILL }},
 631     { &hf_bpdu_flags_port_role,
 632       { "Port Role",                    "stp.flags.port_role",
 633         FT_UINT8,       BASE_DEC,       VALS(role_vals),        BPDU_FLAGS_PORT_ROLE_MASK,
 634         "", HFILL }},
 635     { &hf_bpdu_flags_proposal,
 636       { "Proposal",                     "stp.flags.proposal",
 637         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_PROPOSAL,
 638         "", HFILL }},
 639     { &hf_bpdu_flags_tc,
 640       { "Topology Change",              "stp.flags.tc",
 641         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TC,
 642         "", HFILL }},
 643     { &hf_bpdu_root_mac,
 644       { "Root Identifier",              "stp.root.hw",
 645         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 646         "", HFILL }},
 647     { &hf_bpdu_root_cost,
 648       { "Root Path Cost",               "stp.root.cost",
 649         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 650         "", HFILL }},
 651     { &hf_bpdu_bridge_mac,
 652       { "Bridge Identifier",            "stp.bridge.hw",
 653         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 654         "", HFILL }},
 655     { &hf_bpdu_port_id,
 656       { "Port identifier",              "stp.port",
 657         FT_UINT16,      BASE_HEX,       NULL,   0x0,
 658         "", HFILL }},
 659     { &hf_bpdu_msg_age,
 660       { "Message Age",                  "stp.msg_age",
 661         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 662         "", HFILL }},
 663     { &hf_bpdu_max_age,
 664       { "Max Age",                      "stp.max_age",
 665         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 666         "", HFILL }},
 667     { &hf_bpdu_hello_time,
 668       { "Hello Time",                   "stp.hello",
 669         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 670         "", HFILL }},
 671     { &hf_bpdu_forward_delay,
 672       { "Forward Delay",                "stp.forward",
 673         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 674         "", HFILL }},
 675     { &hf_bpdu_version_1_length,
 676       { "Version 1 Length",             "stp.version_1_length",
 677         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 678         "", HFILL }},
 679     { &hf_bpdu_version_3_length,
 680       { "MST Extension, Length",                "mstp.version_3_length",
 681         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 682         "", HFILL }},
 683     { &hf_bpdu_mst_config_format_selector,
 684       { "MST Config ID format selector",                "mstp.config_format_selector",
 685         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 686         "", HFILL }},
 687     { &hf_bpdu_mst_config_name,
 688       { "MST Config name",              "mstp.config_name",
 689         FT_STRING,      BASE_DEC,       NULL,   0x0,
 690         "", HFILL }},
 691     { &hf_bpdu_mst_config_revision_level,
 692       { "MST Config revision",          "mstp.config_revision_level",
 693         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 694         "", HFILL }},
 695     { &hf_bpdu_mst_config_digest,
 696       { "MST Config digest",            "mstp.config_digest",
 697         FT_BYTES,       BASE_DEC,       NULL,   0x0,
 698         "", HFILL }},
 699     { &hf_bpdu_cist_internal_root_path_cost,
 700       { "CIST Internal Root Path Cost",         "mstp.cist_internal_root_path_cost",
 701         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 702         "", HFILL }},
 703     { &hf_bpdu_cist_bridge_identifier_mac,
 704       { "CIST Bridge Identifier",               "mstp.cist_bridge.hw",
 705         FT_ETHER,       BASE_DEC,       NULL,   0x0,
 706         "", HFILL }},
 707     { &hf_bpdu_cist_remaining_hops,
 708       { "CIST Remaining hops",          "mstp.cist_remaining_hops",
 709         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 710         "", HFILL }},
 711     { &hf_bpdu_msti_flags,
 712       { "MSTI flags",                   "mstp.msti.flags",
 713         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 714         "", HFILL }},
 715     { &hf_bpdu_msti_regional_root_mac,
 716       { "Regional Root",                "mstp.msti.root.hw",
 717         FT_ETHER,       BASE_DEC,       NULL,   0x0,
 718         "", HFILL }},
 719     { &hf_bpdu_msti_internal_root_path_cost,
 720       { "Internal root path cost",              "mstp.msti.root_cost",
 721         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 722         "", HFILL }},
 723     { &hf_bpdu_msti_bridge_identifier_priority,
 724       { "Bridge Identifier Priority",           "mstp.msti.bridge_priority",
 725         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 726         "", HFILL }},
 727     { &hf_bpdu_msti_port_identifier_priority,
 728       { "Port identifier prority",              "mstp.msti.port_priority",
 729         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 730         "", HFILL }},
 731     { &hf_bpdu_msti_remaining_hops,
 732       { "Remaining hops",               "mstp.msti.remaining_hops",
 733         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 734         "", HFILL }},
 735
 736   };
 737   static gint *ett[] = {
 738     &ett_bpdu,
 739     &ett_bpdu_flags,
 740     &ett_mstp,
 741     &ett_msti
 742   };
 743
 744   proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "STP", "stp");
 745   proto_register_field_array(proto_bpdu, hf, array_length(hf));
 746   proto_register_subtree_array(ett, array_length(ett));
 747
 748   register_dissector("bpdu", dissect_bpdu, proto_bpdu);
 749 }
 750
 751 void
 752 proto_reg_handoff_bpdu(void)
 753 {
 754   dissector_handle_t bpdu_handle;
 755
 756   /*
 757    * Get handle for the GVRP dissector.
 758    */
 759   gvrp_handle = find_dissector("gvrp");
 760
 761   /*
 762    * Get handle for the GMRP dissector.
 763    */
 764   gmrp_handle = find_dissector("gmrp");
 765   data_handle = find_dissector("data");
 766
 767   bpdu_handle = find_dissector("bpdu");
 768   dissector_add("llc.dsap", SAP_BPDU, bpdu_handle);
 769   dissector_add("ppp.protocol", PPP_BPDU, bpdu_handle);
 770 }