packet-bpdu.c

   1 /* packet-bpdu.c
   2  * Routines for BPDU (Spanning Tree Protocol) disassembly
   3  *
   4  * $Id: packet-bpdu.c,v 1.47 2003/09/21 20:06:00 gerald 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 "chdlctypes.h"
  38 #include <epan/resolv.h>
  39
  40 /* Offsets of fields within a BPDU */
  41
  42 #define BPDU_IDENTIFIER          0
  43 #define BPDU_VERSION_IDENTIFIER  2
  44 #define BPDU_TYPE                3
  45 #define BPDU_FLAGS               4
  46 #define BPDU_ROOT_IDENTIFIER     5
  47 #define BPDU_ROOT_PATH_COST     13
  48 #define BPDU_BRIDGE_IDENTIFIER  17
  49 #define BPDU_PORT_IDENTIFIER    25
  50 #define BPDU_MESSAGE_AGE        27
  51 #define BPDU_MAX_AGE            29
  52 #define BPDU_HELLO_TIME         31
  53 #define BPDU_FORWARD_DELAY      33
  54 #define BPDU_VERSION_1_LENGTH   35
  55 #define BPDU_VERSION_3_LENGTH   36
  56 #define BPDU_MST_CONFIG_FORMAT_SELECTOR 38
  57 #define BPDU_MST_CONFIG_NAME 39
  58 #define BPDU_MST_CONFIG_REVISION_LEVEL 71
  59 #define BPDU_MST_CONFIG_DIGEST 73
  60 #define BPDU_CIST_INTERNAL_ROOT_PATH_COST 89
  61 #define BPDU_CIST_BRIDGE_IDENTIFIER 93
  62 #define BPDU_CIST_REMAINING_HOPS        101
  63 #define BPDU_MSTI                       102
  64 #define MSTI_FLAGS                      0
  65 #define MSTI_REGIONAL_ROOT              1
  66 #define MSTI_INTERNAL_ROOT_PATH_COST    9
  67 #define MSTI_BRIDGE_IDENTIFIER_PRIORITY 13
  68 #define MSTI_PORT_IDENTIFIER_PRIORITY   14
  69 #define MSTI_REMAINING_HOPS             15
  70
  71 #define CONF_BPDU_SIZE          35
  72 #define TC_BPDU_SIZE            4
  73 #define RST_BPDU_SIZE           36
  74 #define VERSION_3_STATIC_LENGTH 64
  75 #define MSTI_MESSAGE_SIZE       16
  76
  77 /* Flag bits */
  78
  79 #define BPDU_FLAGS_TCACK                0x80
  80 #define BPDU_FLAGS_AGREEMENT            0x40
  81 #define BPDU_FLAGS_FORWARDING           0x20
  82 #define BPDU_FLAGS_LEARNING             0x10
  83 #define BPDU_FLAGS_PORT_ROLE_MASK       0x0C
  84 #define BPDU_FLAGS_PORT_ROLE_SHIFT      2
  85 #define BPDU_FLAGS_PROPOSAL             0x02
  86 #define BPDU_FLAGS_TC                   0x01
  87
  88 static int proto_bpdu = -1;
  89 static int hf_bpdu_proto_id = -1;
  90 static int hf_bpdu_version_id = -1;
  91 static int hf_bpdu_type = -1;
  92 static int hf_bpdu_flags = -1;
  93 static int hf_bpdu_flags_tcack = -1;
  94 static int hf_bpdu_flags_agreement = -1;
  95 static int hf_bpdu_flags_forwarding = -1;
  96 static int hf_bpdu_flags_learning = -1;
  97 static int hf_bpdu_flags_port_role = -1;
  98 static int hf_bpdu_flags_proposal = -1;
  99 static int hf_bpdu_flags_tc = -1;
 100 static int hf_bpdu_root_mac = -1;
 101 static int hf_bpdu_root_cost = -1;
 102 static int hf_bpdu_bridge_mac = -1;
 103 static int hf_bpdu_port_id = -1;
 104 static int hf_bpdu_msg_age = -1;
 105 static int hf_bpdu_max_age = -1;
 106 static int hf_bpdu_hello_time = -1;
 107 static int hf_bpdu_forward_delay = -1;
 108 static int hf_bpdu_version_1_length = -1;
 109 static int hf_bpdu_version_3_length = -1;
 110 static int hf_bpdu_mst_config_format_selector = -1;
 111 static int hf_bpdu_mst_config_name = -1;
 112 static int hf_bpdu_mst_config_revision_level = -1;
 113 static int hf_bpdu_mst_config_digest = -1;
 114 static int hf_bpdu_cist_internal_root_path_cost = -1;
 115 static int hf_bpdu_cist_bridge_identifier_mac = -1;
 116 static int hf_bpdu_cist_remaining_hops = -1;
 117 static int hf_bpdu_msti_flags = -1;
 118 static int hf_bpdu_msti_regional_root_mac = -1;
 119 static int hf_bpdu_msti_internal_root_path_cost = -1;
 120 static int hf_bpdu_msti_bridge_identifier_priority = -1;
 121 static int hf_bpdu_msti_port_identifier_priority = -1;
 122 static int hf_bpdu_msti_remaining_hops = -1;
 123
 124 static gint ett_bpdu = -1;
 125 static gint ett_bpdu_flags = -1;
 126 static gint ett_mstp = -1;
 127 static gint ett_msti = -1;
 128
 129 static dissector_handle_t gvrp_handle;
 130 static dissector_handle_t gmrp_handle;
 131 static dissector_handle_t data_handle;
 132
 133 static const value_string protocol_id_vals[] = {
 134         { 0, "Spanning Tree Protocol" },
 135         { 0, NULL }
 136 };
 137
 138 #define BPDU_TYPE_CONF                  0x00    /* STP Configuration BPDU */
 139 #define BPDU_TYPE_RST                   0x02    /* RST BPDU (or MST) */
 140 #define BPDU_TYPE_TOPOLOGY_CHANGE       0x80    /* STP TCN (Topology change notify) BPDU */
 141
 142 static const value_string bpdu_type_vals[] = {
 143         { BPDU_TYPE_CONF,            "Configuration" },
 144         { BPDU_TYPE_RST,             "Rapid/Multiple Spanning Tree" },
 145         { BPDU_TYPE_TOPOLOGY_CHANGE, "Topology Change Notification" },
 146         { 0,                         NULL }
 147 };
 148
 149 #define PROTO_VERSION_STP       0
 150 #define PROTO_VERSION_RSTP      2
 151 #define PROTO_VERSION_MSTP      3
 152
 153 static const value_string version_id_vals[] = {
 154         { PROTO_VERSION_STP,    "Spanning Tree" },
 155         { PROTO_VERSION_RSTP,   "Rapid Spanning Tree" },
 156         { PROTO_VERSION_MSTP,   "Multiple Spanning Tree" },
 157         { 0,                    NULL}
 158 };
 159 static const value_string role_vals[] = {
 160         { 1, "Alternate or Backup" },
 161         { 2, "Root" },
 162         { 3, "Designated" },
 163         { 0, NULL }
 164 };
 165
 166 static const char initial_sep[] = " (";
 167 static const char cont_sep[] = ", ";
 168
 169 #define APPEND_BOOLEAN_FLAG(flag, item, string) \
 170         if(flag){                                                       \
 171                 if(item)                                                \
 172                         proto_item_append_text(item, string, sep);      \
 173                 sep = cont_sep;                                         \
 174         }
 175
 176 static void
 177 dissect_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 178 {
 179       guint16 protocol_identifier;
 180       guint8  protocol_version_identifier;
 181       guint8  bpdu_type;
 182       guint8  flags;
 183       guint16 root_identifier_bridge_priority;
 184       const guint8  *root_identifier_mac;
 185       gchar   *root_identifier_mac_str;
 186       guint32 root_path_cost;
 187       guint16 bridge_identifier_bridge_priority;
 188       const guint8  *bridge_identifier_mac;
 189       gchar   *bridge_identifier_mac_str;
 190       guint16 port_identifier;
 191       double message_age;
 192       double max_age;
 193       double hello_time;
 194       double forward_delay;
 195       guint16 version_3_length;
 196       guint32 cist_internal_root_path_cost;
 197       guint8 mst_config_format_selector;
 198       guint16 cist_bridge_identifier_bridge_priority;
 199       const guint8  *cist_bridge_identifier_mac;
 200       gchar   *cist_bridge_identifier_mac_str;
 201       const guint8 *mst_config_name;
 202       guint16 mst_config_revision_level;
 203       guint8 cist_remaining_hops, msti_remaining_hops;
 204       guint32 msti_internal_root_path_cost;
 205       guint32 msti_regional_root_mstid, msti_regional_root_priority;
 206       const guint8  *msti_regional_root_mac;
 207       gchar   *msti_regional_root_mac_str;
 208       guint8 msti_bridge_identifier_priority, msti_port_identifier_priority;
 209       int       length, offset, msti;
 210
 211       proto_tree *bpdu_tree;
 212       proto_tree *mstp_tree, *msti_tree;
 213       proto_item *bpdu_item;
 214       proto_item *mstp_item, *msti_item;
 215       proto_tree *flags_tree;
 216       proto_item *flags_item;
 217       guint8    rstp_bpdu, mstp_bpdu=0;
 218       const char *sep;
 219
 220       /* GARP application frames require special interpretation of the
 221          destination address field; otherwise, they will be mistaken as
 222          BPDU frames.
 223          Fortunately, they can be recognized by checking the first 6 octets
 224          of the destination address, which are in the range from
 225          01-80-C2-00-00-20 to 01-80-C2-00-00-2F.
 226
 227          Yes - we *do* need to check the destination address type;
 228          on Linux cooked captures, there *is* no destination address,
 229          so it's AT_NONE. */
 230       if (pinfo->dl_dst.type == AT_ETHER &&
 231           pinfo->dl_dst.data[0] == 0x01 && pinfo->dl_dst.data[1] == 0x80 &&
 232           pinfo->dl_dst.data[2] == 0xC2 && pinfo->dl_dst.data[3] == 0x00 &&
 233           pinfo->dl_dst.data[4] == 0x00 && ((pinfo->dl_dst.data[5] & 0xF0) == 0x20)) {
 234
 235             protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
 236
 237             switch (pinfo->dl_dst.data[5]) {
 238
 239             case 0x20:
 240                    /* for GMRP */
 241                   call_dissector(gmrp_handle, tvb, pinfo, tree);
 242                   return;
 243
 244             case 0x21:
 245                   /* for GVRP */
 246                   call_dissector(gvrp_handle, tvb, pinfo, tree);
 247                   return;
 248             }
 249
 250             pinfo->current_proto = "GARP";
 251
 252             if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 253                     col_set_str(pinfo->cinfo, COL_PROTOCOL, "GARP");
 254                     /* Generic Attribute Registration Protocol */
 255             }
 256
 257             if (check_col(pinfo->cinfo, COL_INFO)) {
 258                     col_add_fstr(pinfo->cinfo, COL_INFO,
 259                         "Unknown GARP application (0x%02X)",
 260                         pinfo->dl_dst.data[5]);
 261             }
 262
 263             return;
 264       }
 265
 266       if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 267             col_set_str(pinfo->cinfo, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
 268       }
 269       if (check_col(pinfo->cinfo, COL_INFO)) {
 270             col_clear(pinfo->cinfo, COL_INFO);
 271       }
 272
 273       bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
 274
 275       protocol_version_identifier = tvb_get_guint8(tvb, BPDU_VERSION_IDENTIFIER);
 276
 277       switch (bpdu_type) {
 278
 279       case BPDU_TYPE_CONF:
 280       case BPDU_TYPE_RST:
 281             flags = tvb_get_guint8(tvb, BPDU_FLAGS);
 282             root_identifier_bridge_priority = tvb_get_ntohs(tvb,BPDU_ROOT_IDENTIFIER);
 283             root_identifier_mac = tvb_get_ptr(tvb, BPDU_ROOT_IDENTIFIER + 2, 6);
 284             root_identifier_mac_str = ether_to_str(root_identifier_mac);
 285             root_path_cost = tvb_get_ntohl(tvb, BPDU_ROOT_PATH_COST);
 286             port_identifier = tvb_get_ntohs(tvb, BPDU_PORT_IDENTIFIER);
 287             break;
 288
 289       default:
 290             /* Squelch GCC complaints. */
 291             flags = 0;
 292             root_identifier_bridge_priority = 0;
 293             root_identifier_mac = NULL;
 294             root_identifier_mac_str = NULL;
 295             root_path_cost = 0;
 296             port_identifier = 0;
 297             break;
 298       }
 299
 300       if (check_col(pinfo->cinfo, COL_INFO)) {
 301             switch (bpdu_type) {
 302
 303             case BPDU_TYPE_CONF:
 304                   col_add_fstr(pinfo->cinfo, COL_INFO, "Conf. %sRoot = %d/%s  Cost = %d  Port = 0x%04x",
 305                                flags & 0x1 ? "TC + " : "",
 306                                root_identifier_bridge_priority, root_identifier_mac_str, root_path_cost,
 307                                port_identifier);
 308                   break;
 309
 310             case BPDU_TYPE_TOPOLOGY_CHANGE:
 311                   col_add_fstr(pinfo->cinfo, COL_INFO, "Topology Change Notification");
 312                   break;
 313
 314             case BPDU_TYPE_RST:
 315                   col_add_fstr(pinfo->cinfo, COL_INFO, "%cST. %sRoot = %d/%s  Cost = %d  Port = 0x%04x",
 316                                protocol_version_identifier == 3 ? 'M':'R',
 317                                flags & 0x1 ? "TC + " : "",
 318                                root_identifier_bridge_priority, root_identifier_mac_str, root_path_cost,
 319                                port_identifier);
 320                   break;
 321
 322             default:
 323                   col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown BPDU type (%u)",
 324                                bpdu_type);
 325                   break;
 326             }
 327       }
 328
 329       switch (bpdu_type) {
 330
 331       case BPDU_TYPE_CONF:
 332         set_actual_length(tvb, CONF_BPDU_SIZE);
 333         break;
 334
 335       case BPDU_TYPE_TOPOLOGY_CHANGE:
 336         set_actual_length(tvb, TC_BPDU_SIZE);
 337         break;
 338
 339       case BPDU_TYPE_RST:
 340         if (protocol_version_identifier == 3) {
 341             version_3_length = tvb_get_ntohs(tvb, BPDU_VERSION_3_LENGTH);
 342             set_actual_length(tvb, RST_BPDU_SIZE + 2 + version_3_length);
 343         } else
 344             set_actual_length(tvb, RST_BPDU_SIZE);
 345         break;
 346       }
 347
 348       if (tree) {
 349             bpdu_item = proto_tree_add_protocol_format(tree, proto_bpdu, tvb,
 350                                 0, -1, "Spanning Tree Protocol");
 351             bpdu_tree = proto_item_add_subtree(bpdu_item, ett_bpdu);
 352
 353             protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
 354             proto_tree_add_uint(bpdu_tree, hf_bpdu_proto_id, tvb,
 355                                 BPDU_IDENTIFIER, 2, protocol_identifier);
 356
 357             proto_tree_add_uint(bpdu_tree, hf_bpdu_version_id, tvb,
 358                                 BPDU_VERSION_IDENTIFIER, 1,
 359                                 protocol_version_identifier);
 360             switch (protocol_version_identifier) {
 361               case 0:
 362                 break;
 363               case 2:
 364               case 3:
 365                 break;
 366               default:
 367                   proto_tree_add_text(bpdu_tree, tvb, BPDU_VERSION_IDENTIFIER, 1,
 368                   "   (Warning: this version of Ethereal only knows about versions 0, 2 & 3)");
 369                 break;
 370             }
 371             proto_tree_add_uint(bpdu_tree, hf_bpdu_type, tvb,
 372                                        BPDU_TYPE, 1,
 373                                        bpdu_type);
 374
 375             if (bpdu_type != BPDU_TYPE_CONF && bpdu_type != BPDU_TYPE_RST) {
 376               call_dissector(data_handle,
 377                              tvb_new_subset(tvb, BPDU_TYPE + 1, -1, -1),
 378                              pinfo, tree);
 379               return;
 380             }
 381
 382             rstp_bpdu = (bpdu_type == BPDU_TYPE_RST);
 383             if (rstp_bpdu) mstp_bpdu = (protocol_version_identifier == 3);
 384
 385             bridge_identifier_bridge_priority = tvb_get_ntohs(tvb, BPDU_BRIDGE_IDENTIFIER);
 386             bridge_identifier_mac = tvb_get_ptr(tvb, BPDU_BRIDGE_IDENTIFIER + 2, 6);
 387             bridge_identifier_mac_str = ether_to_str(bridge_identifier_mac);
 388
 389             flags_item = proto_tree_add_uint(bpdu_tree, hf_bpdu_flags, tvb,
 390                                 BPDU_FLAGS, 1, flags);
 391             flags_tree = proto_item_add_subtree(flags_item, ett_bpdu_flags);
 392             sep = initial_sep;
 393             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TCACK, flags_item,
 394                                 "%sTopology Change Acknowledgment");
 395             proto_tree_add_boolean(flags_tree, hf_bpdu_flags_tcack, tvb,
 396                                 BPDU_FLAGS, 1, flags);
 397             if (rstp_bpdu) {
 398               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_AGREEMENT, flags_item,
 399                                   "%sAgreement");
 400               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_agreement, tvb,
 401                                   BPDU_FLAGS, 1, flags);
 402               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_FORWARDING, flags_item,
 403                                   "%sForwarding");
 404               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_forwarding, tvb,
 405                                   BPDU_FLAGS, 1, flags);
 406               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_LEARNING, flags_item,
 407                                   "%sLearning");
 408               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_learning, tvb,
 409                                   BPDU_FLAGS, 1, flags);
 410               if (flags_item) {
 411                 guint8 port_role;
 412
 413                 port_role = (flags & BPDU_FLAGS_PORT_ROLE_MASK) >> BPDU_FLAGS_PORT_ROLE_SHIFT;
 414                 proto_item_append_text(flags_item, "%sPort Role: %s", sep,
 415                                        val_to_str(port_role, role_vals,
 416                                                   "Unknown (%u)"));
 417               }
 418               sep = cont_sep;
 419               proto_tree_add_uint(flags_tree, hf_bpdu_flags_port_role, tvb,
 420                                   BPDU_FLAGS, 1, flags);
 421               APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_PROPOSAL, flags_item,
 422                                   "%sProposal");
 423               proto_tree_add_boolean(flags_tree, hf_bpdu_flags_proposal, tvb,
 424                                   BPDU_FLAGS, 1, flags);
 425             }
 426             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TC, flags_item,
 427                                 "%sTopology Change");
 428             proto_tree_add_boolean(flags_tree, hf_bpdu_flags_tc, tvb,
 429                                 BPDU_FLAGS, 1, flags);
 430             if (sep != initial_sep) {
 431               /* We put something in; put in the terminating ")" */
 432               proto_item_append_text(flags_item, ")");
 433             }
 434
 435             proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_root_mac, tvb,
 436                                        BPDU_ROOT_IDENTIFIER + 2, 6,
 437                                        root_identifier_mac);
 438             proto_tree_add_text(bpdu_tree, tvb,
 439                                 BPDU_ROOT_IDENTIFIER, 8,
 440                                 "Root Identifier: %d / %s",
 441                                 root_identifier_bridge_priority,
 442                                 root_identifier_mac_str);
 443             proto_tree_add_uint(bpdu_tree, hf_bpdu_root_cost, tvb,
 444                                 BPDU_ROOT_PATH_COST, 4,
 445                                 root_path_cost);
 446             proto_tree_add_text(bpdu_tree, tvb,
 447                                 BPDU_BRIDGE_IDENTIFIER, 8,
 448                                 "Bridge Identifier: %d / %s",
 449                                 bridge_identifier_bridge_priority,
 450                                 bridge_identifier_mac_str);
 451             proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_bridge_mac, tvb,
 452                                        BPDU_BRIDGE_IDENTIFIER + 2, 6,
 453                                        bridge_identifier_mac);
 454             proto_tree_add_uint(bpdu_tree, hf_bpdu_port_id, tvb,
 455                                 BPDU_PORT_IDENTIFIER, 2,
 456                                 port_identifier);
 457             message_age = tvb_get_ntohs(tvb, BPDU_MESSAGE_AGE) / 256.0;
 458             proto_tree_add_double(bpdu_tree, hf_bpdu_msg_age, tvb,
 459                                 BPDU_MESSAGE_AGE, 2,
 460                                 message_age);
 461             max_age = tvb_get_ntohs(tvb, BPDU_MAX_AGE) / 256.0;
 462             proto_tree_add_double(bpdu_tree, hf_bpdu_max_age, tvb,
 463                                 BPDU_MAX_AGE, 2,
 464                                 max_age);
 465             hello_time = tvb_get_ntohs(tvb, BPDU_HELLO_TIME) / 256.0;
 466             proto_tree_add_double(bpdu_tree, hf_bpdu_hello_time, tvb,
 467                                 BPDU_HELLO_TIME, 2,
 468                                 hello_time);
 469             forward_delay = tvb_get_ntohs(tvb, BPDU_FORWARD_DELAY) / 256.0;
 470             proto_tree_add_double(bpdu_tree, hf_bpdu_forward_delay, tvb,
 471                                 BPDU_FORWARD_DELAY, 2,
 472                                 forward_delay);
 473             if (rstp_bpdu) {
 474               proto_tree_add_item(bpdu_tree, hf_bpdu_version_1_length, tvb,
 475                                 BPDU_VERSION_1_LENGTH, 1, FALSE);
 476             }
 477             if (mstp_bpdu) {
 478                 version_3_length = tvb_get_ntohs(tvb, BPDU_VERSION_3_LENGTH);
 479
 480                 mstp_item = proto_tree_add_uint(bpdu_tree, hf_bpdu_version_3_length, tvb,
 481                         BPDU_VERSION_3_LENGTH, 2, version_3_length);
 482                 mstp_tree = proto_item_add_subtree(mstp_item, ett_mstp);
 483
 484                 mst_config_format_selector = tvb_get_guint8(tvb, BPDU_MST_CONFIG_FORMAT_SELECTOR);
 485                 proto_tree_add_uint(mstp_tree, hf_bpdu_mst_config_format_selector, tvb,
 486                         BPDU_MST_CONFIG_FORMAT_SELECTOR, 1, mst_config_format_selector);
 487                 mst_config_name =  tvb_get_ptr (tvb, BPDU_MST_CONFIG_NAME, 32);
 488                 proto_tree_add_string(mstp_tree, hf_bpdu_mst_config_name, tvb, BPDU_MST_CONFIG_NAME, 32, mst_config_name);
 489
 490                 mst_config_revision_level = tvb_get_ntohs(tvb, BPDU_MST_CONFIG_REVISION_LEVEL);
 491                 proto_tree_add_uint(mstp_tree, hf_bpdu_mst_config_revision_level, tvb,
 492                         BPDU_MST_CONFIG_REVISION_LEVEL, 2, mst_config_revision_level);
 493                 proto_tree_add_bytes(mstp_tree, hf_bpdu_mst_config_digest, tvb,
 494                         BPDU_MST_CONFIG_DIGEST, 16, tvb_get_ptr(tvb, BPDU_MST_CONFIG_DIGEST, 16));
 495
 496                 cist_internal_root_path_cost = tvb_get_ntohl(tvb, BPDU_CIST_INTERNAL_ROOT_PATH_COST);
 497                 proto_tree_add_uint(mstp_tree, hf_bpdu_cist_internal_root_path_cost, tvb,
 498                         BPDU_CIST_INTERNAL_ROOT_PATH_COST, 4, cist_internal_root_path_cost);
 499
 500                 cist_bridge_identifier_bridge_priority = tvb_get_ntohs(tvb,BPDU_CIST_BRIDGE_IDENTIFIER);
 501                 cist_bridge_identifier_mac = tvb_get_ptr(tvb, BPDU_CIST_BRIDGE_IDENTIFIER + 2, 6);
 502                 cist_bridge_identifier_mac_str = ether_to_str(cist_bridge_identifier_mac);
 503                 proto_tree_add_text(mstp_tree, tvb, BPDU_CIST_BRIDGE_IDENTIFIER, 8,
 504                                 "CIST Bridge Identifier: %d / %s",
 505                                 cist_bridge_identifier_bridge_priority,
 506                                 cist_bridge_identifier_mac_str);
 507                 proto_tree_add_ether_hidden(mstp_tree, hf_bpdu_cist_bridge_identifier_mac, tvb,
 508                                        BPDU_CIST_BRIDGE_IDENTIFIER + 2, 6,
 509                                        cist_bridge_identifier_mac);
 510
 511                 cist_remaining_hops = tvb_get_guint8(tvb, BPDU_CIST_REMAINING_HOPS);
 512                 proto_tree_add_uint(mstp_tree, hf_bpdu_cist_remaining_hops, tvb,
 513                         BPDU_CIST_REMAINING_HOPS, 1, cist_remaining_hops);
 514
 515         /* MSTI messages */
 516                 length = version_3_length - VERSION_3_STATIC_LENGTH;
 517                 offset = BPDU_MSTI;
 518                 msti = 1;
 519                 while (length >= MSTI_MESSAGE_SIZE) {
 520                     msti_regional_root_mstid = tvb_get_guint8(tvb,  offset+ MSTI_REGIONAL_ROOT);
 521                     msti_regional_root_priority = (msti_regional_root_mstid &0xf0) << 8;
 522                     msti_regional_root_mstid = ((msti_regional_root_mstid & 0x0f) << 8) +
 523                                 tvb_get_guint8(tvb,  offset+ MSTI_REGIONAL_ROOT+1);
 524                     msti_regional_root_mac = tvb_get_ptr(tvb, offset+ MSTI_REGIONAL_ROOT + 2, 6);
 525                     msti_regional_root_mac_str = ether_to_str(msti_regional_root_mac);
 526
 527                     msti_item = proto_tree_add_text(mstp_tree, tvb, offset, 16,
 528                         "MSTID %d, Regional Root Identifier %d / %s",
 529                         msti_regional_root_mstid, msti_regional_root_priority,
 530                         msti_regional_root_mac_str);
 531                     msti_tree = proto_item_add_subtree(msti_item, ett_msti);
 532
 533                     /* flags */
 534                     flags = tvb_get_guint8(tvb, offset+MSTI_FLAGS);
 535                     flags_item = proto_tree_add_uint(msti_tree, hf_bpdu_msti_flags, tvb,
 536                         offset+MSTI_FLAGS, 1, flags);
 537                     flags_tree = proto_item_add_subtree(flags_item, ett_bpdu_flags);
 538
 539                     sep = initial_sep;
 540                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TCACK, flags_item, "%sMaster");
 541                     proto_tree_add_boolean(flags_tree, hf_bpdu_flags_tcack, tvb,
 542                         offset+MSTI_FLAGS, 1, flags);
 543                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_AGREEMENT, flags_item, "%sAgreement");
 544                     proto_tree_add_boolean(flags_tree, hf_bpdu_flags_agreement, tvb,
 545                         offset+MSTI_FLAGS, 1, flags);
 546                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_FORWARDING, flags_item, "%sForwarding");
 547                     proto_tree_add_boolean(flags_tree, hf_bpdu_flags_forwarding, tvb,
 548                         offset+MSTI_FLAGS, 1, flags);
 549                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_LEARNING, flags_item, "%sLearning");
 550                     proto_tree_add_boolean(flags_tree, hf_bpdu_flags_learning, tvb,
 551                         offset+MSTI_FLAGS, 1, flags);
 552                     if (flags_item) {
 553                         guint8 port_role;
 554                         port_role = (flags & BPDU_FLAGS_PORT_ROLE_MASK) >> BPDU_FLAGS_PORT_ROLE_SHIFT;
 555                         proto_item_append_text(flags_item, "%sPort Role: %s", sep,
 556                                        val_to_str(port_role, role_vals, "Unknown (%u)"));
 557                     }
 558                     proto_tree_add_uint(flags_tree, hf_bpdu_flags_port_role, tvb,
 559                         offset+MSTI_FLAGS, 1, flags);
 560                     sep = cont_sep;
 561                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_PROPOSAL, flags_item, "%sProposal");
 562                     proto_tree_add_boolean(flags_tree, hf_bpdu_flags_proposal, tvb,
 563                         offset+MSTI_FLAGS, 1, flags);
 564                     APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TC, flags_item, "%sTopology Change");
 565                     proto_tree_add_boolean(flags_tree, hf_bpdu_flags_tc, tvb,
 566                         offset+MSTI_FLAGS, 1, flags);
 567                     if (sep != initial_sep) {         /* We put something in; put in the terminating ")" */
 568                         proto_item_append_text(flags_item, ")");
 569                     }
 570
 571                     /* pri, MSTID, Regional root */
 572                     proto_tree_add_ether_hidden(msti_tree, hf_bpdu_msti_regional_root_mac, tvb,
 573                                        offset + MSTI_REGIONAL_ROOT + 2, 6,
 574                                        msti_regional_root_mac);
 575                     proto_tree_add_text(msti_tree, tvb, offset + MSTI_REGIONAL_ROOT, 8,
 576                                 "MSTID %d, priority %d Root Identifier %s",
 577                                 msti_regional_root_mstid, msti_regional_root_priority,
 578                                 msti_regional_root_mac_str);
 579
 580
 581                     msti_internal_root_path_cost = tvb_get_ntohs(tvb, offset+MSTI_INTERNAL_ROOT_PATH_COST);
 582                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_internal_root_path_cost, tvb,
 583                         offset+MSTI_INTERNAL_ROOT_PATH_COST, 4, msti_internal_root_path_cost);
 584
 585                     msti_bridge_identifier_priority = tvb_get_guint8(tvb, offset+MSTI_BRIDGE_IDENTIFIER_PRIORITY) >> 4;
 586                     msti_port_identifier_priority = tvb_get_guint8(tvb, offset+MSTI_PORT_IDENTIFIER_PRIORITY) >> 4;
 587
 588                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_bridge_identifier_priority, tvb,
 589                         offset+MSTI_BRIDGE_IDENTIFIER_PRIORITY, 1, msti_bridge_identifier_priority);
 590                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_port_identifier_priority, tvb,
 591                         offset+MSTI_PORT_IDENTIFIER_PRIORITY, 1, msti_port_identifier_priority);
 592
 593                     msti_remaining_hops = tvb_get_guint8(tvb, offset+MSTI_REMAINING_HOPS);
 594                     proto_tree_add_uint(msti_tree, hf_bpdu_msti_remaining_hops, tvb,
 595                         offset + MSTI_REMAINING_HOPS, 1, msti_remaining_hops);
 596
 597                     length -= MSTI_MESSAGE_SIZE;
 598                     offset += MSTI_MESSAGE_SIZE;
 599                     msti++;
 600                 }
 601
 602             }
 603       }
 604 }
 605
 606 static const true_false_string yesno = {
 607         "Yes",
 608         "No"
 609 };
 610
 611 void
 612 proto_register_bpdu(void)
 613 {
 614
 615   static hf_register_info hf[] = {
 616     { &hf_bpdu_proto_id,
 617       { "Protocol Identifier",          "stp.protocol",
 618         FT_UINT16,      BASE_HEX,       VALS(&protocol_id_vals), 0x0,
 619         "", HFILL }},
 620     { &hf_bpdu_version_id,
 621       { "Protocol Version Identifier",  "stp.version",
 622         FT_UINT8,       BASE_DEC,       VALS(&version_id_vals), 0x0,
 623         "", HFILL }},
 624     { &hf_bpdu_type,
 625       { "BPDU Type",                    "stp.type",
 626         FT_UINT8,       BASE_HEX,       VALS(&bpdu_type_vals),  0x0,
 627         "", HFILL }},
 628     { &hf_bpdu_flags,
 629       { "BPDU flags",                   "stp.flags",
 630         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 631         "", HFILL }},
 632     { &hf_bpdu_flags_tcack,
 633       { "Topology Change Acknowledgment",  "stp.flags.tcack",
 634         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TCACK,
 635         "", HFILL }},
 636     { &hf_bpdu_flags_agreement,
 637       { "Agreement",                    "stp.flags.agreement",
 638         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_AGREEMENT,
 639         "", HFILL }},
 640     { &hf_bpdu_flags_forwarding,
 641       { "Forwarding",                   "stp.flags.forwarding",
 642         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_FORWARDING,
 643         "", HFILL }},
 644     { &hf_bpdu_flags_learning,
 645       { "Learning",                     "stp.flags.learning",
 646         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_LEARNING,
 647         "", HFILL }},
 648     { &hf_bpdu_flags_port_role,
 649       { "Port Role",                    "stp.flags.port_role",
 650         FT_UINT8,       BASE_DEC,       VALS(role_vals),        BPDU_FLAGS_PORT_ROLE_MASK,
 651         "", HFILL }},
 652     { &hf_bpdu_flags_proposal,
 653       { "Proposal",                     "stp.flags.proposal",
 654         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_PROPOSAL,
 655         "", HFILL }},
 656     { &hf_bpdu_flags_tc,
 657       { "Topology Change",              "stp.flags.tc",
 658         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TC,
 659         "", HFILL }},
 660     { &hf_bpdu_root_mac,
 661       { "Root Identifier",              "stp.root.hw",
 662         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 663         "", HFILL }},
 664     { &hf_bpdu_root_cost,
 665       { "Root Path Cost",               "stp.root.cost",
 666         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 667         "", HFILL }},
 668     { &hf_bpdu_bridge_mac,
 669       { "Bridge Identifier",            "stp.bridge.hw",
 670         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 671         "", HFILL }},
 672     { &hf_bpdu_port_id,
 673       { "Port identifier",              "stp.port",
 674         FT_UINT16,      BASE_HEX,       NULL,   0x0,
 675         "", HFILL }},
 676     { &hf_bpdu_msg_age,
 677       { "Message Age",                  "stp.msg_age",
 678         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 679         "", HFILL }},
 680     { &hf_bpdu_max_age,
 681       { "Max Age",                      "stp.max_age",
 682         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 683         "", HFILL }},
 684     { &hf_bpdu_hello_time,
 685       { "Hello Time",                   "stp.hello",
 686         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 687         "", HFILL }},
 688     { &hf_bpdu_forward_delay,
 689       { "Forward Delay",                "stp.forward",
 690         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 691         "", HFILL }},
 692     { &hf_bpdu_version_1_length,
 693       { "Version 1 Length",             "stp.version_1_length",
 694         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 695         "", HFILL }},
 696     { &hf_bpdu_version_3_length,
 697       { "MST Extension, Length",                "mstp.version_3_length",
 698         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 699         "", HFILL }},
 700     { &hf_bpdu_mst_config_format_selector,
 701       { "MST Config ID format selector",                "mstp.config_format_selector",
 702         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 703         "", HFILL }},
 704     { &hf_bpdu_mst_config_name,
 705       { "MST Config name",              "mstp.config_name",
 706         FT_STRING,      BASE_DEC,       NULL,   0x0,
 707         "", HFILL }},
 708     { &hf_bpdu_mst_config_revision_level,
 709       { "MST Config revision",          "mstp.config_revision_level",
 710         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 711         "", HFILL }},
 712     { &hf_bpdu_mst_config_digest,
 713       { "MST Config digest",            "mstp.config_digest",
 714         FT_BYTES,       BASE_DEC,       NULL,   0x0,
 715         "", HFILL }},
 716     { &hf_bpdu_cist_internal_root_path_cost,
 717       { "CIST Internal Root Path Cost",         "mstp.cist_internal_root_path_cost",
 718         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 719         "", HFILL }},
 720     { &hf_bpdu_cist_bridge_identifier_mac,
 721       { "CIST Bridge Identifier",               "mstp.cist_bridge.hw",
 722         FT_ETHER,       BASE_DEC,       NULL,   0x0,
 723         "", HFILL }},
 724     { &hf_bpdu_cist_remaining_hops,
 725       { "CIST Remaining hops",          "mstp.cist_remaining_hops",
 726         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 727         "", HFILL }},
 728     { &hf_bpdu_msti_flags,
 729       { "MSTI flags",                   "mstp.msti.flags",
 730         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 731         "", HFILL }},
 732     { &hf_bpdu_msti_regional_root_mac,
 733       { "Regional Root",                "mstp.msti.root.hw",
 734         FT_ETHER,       BASE_DEC,       NULL,   0x0,
 735         "", HFILL }},
 736     { &hf_bpdu_msti_internal_root_path_cost,
 737       { "Internal root path cost",              "mstp.msti.root_cost",
 738         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 739         "", HFILL }},
 740     { &hf_bpdu_msti_bridge_identifier_priority,
 741       { "Bridge Identifier Priority",           "mstp.msti.bridge_priority",
 742         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 743         "", HFILL }},
 744     { &hf_bpdu_msti_port_identifier_priority,
 745       { "Port identifier prority",              "mstp.msti.port_priority",
 746         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 747         "", HFILL }},
 748     { &hf_bpdu_msti_remaining_hops,
 749       { "Remaining hops",               "mstp.msti.remaining_hops",
 750         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 751         "", HFILL }},
 752
 753   };
 754   static gint *ett[] = {
 755     &ett_bpdu,
 756     &ett_bpdu_flags,
 757     &ett_mstp,
 758     &ett_msti
 759   };
 760
 761   proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "STP", "stp");
 762   proto_register_field_array(proto_bpdu, hf, array_length(hf));
 763   proto_register_subtree_array(ett, array_length(ett));
 764
 765   register_dissector("bpdu", dissect_bpdu, proto_bpdu);
 766 }
 767
 768 void
 769 proto_reg_handoff_bpdu(void)
 770 {
 771   dissector_handle_t bpdu_handle;
 772
 773   /*
 774    * Get handle for the GVRP dissector.
 775    */
 776   gvrp_handle = find_dissector("gvrp");
 777
 778   /*
 779    * Get handle for the GMRP dissector.
 780    */
 781   gmrp_handle = find_dissector("gmrp");
 782   data_handle = find_dissector("data");
 783
 784   bpdu_handle = find_dissector("bpdu");
 785   dissector_add("llc.dsap", SAP_BPDU, bpdu_handle);
 786   dissector_add("ppp.protocol", PPP_BPDU, bpdu_handle);
 787   dissector_add("chdlctype", CHDLCTYPE_BPDU, bpdu_handle);
 788 }