packet-bpdu.c

   1 /* packet-bpdu.c
   2  * Routines for BPDU (Spanning Tree Protocol) disassembly
   3  *
   4  * $Id: packet-bpdu.c,v 1.9 2000/04/17 00:32:37 guy Exp $
   5  *
   6  * Copyright 1999 Christophe Tronche <ch.tronche@computer.org>
   7  *
   8  * Ethereal - Network traffic analyzer
   9  * By Gerald Combs <gerald@zing.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #ifdef HAVE_SYS_TYPES_H
  33 # include <sys/types.h>
  34 #endif
  35
  36 #ifdef HAVE_NETINET_IN_H
  37 # include <netinet/in.h>
  38 #endif
  39
  40 #include <stdio.h>
  41 #include <string.h>
  42 #include <glib.h>
  43 #include "packet.h"
  44 #include "llcsaps.h"
  45 #include "resolv.h"
  46
  47 /* Offsets of fields within a BPDU */
  48
  49 #define BPDU_IDENTIFIER          0
  50 #define BPDU_VERSION_IDENTIFIER  2
  51 #define BPDU_TYPE                3
  52 #define BPDU_FLAGS               4
  53 #define BPDU_ROOT_IDENTIFIER     5
  54 #define BPDU_ROOT_PATH_COST     13
  55 #define BPDU_BRIDGE_IDENTIFIER  17
  56 #define BPDU_PORT_IDENTIFIER    25
  57 #define BPDU_MESSAGE_AGE        27
  58 #define BPDU_MAX_AGE            29
  59 #define BPDU_HELLO_TIME         31
  60 #define BPDU_FORWARD_DELAY      33
  61
  62 static int proto_bpdu = -1;
  63 static int hf_bpdu_proto_id = -1;
  64 static int hf_bpdu_version_id = -1;
  65 static int hf_bpdu_type = -1;
  66 static int hf_bpdu_flags = -1;
  67 static int hf_bpdu_root_mac = -1;
  68 static int hf_bpdu_root_cost = -1;
  69 static int hf_bpdu_bridge_mac = -1;
  70 static int hf_bpdu_port_id = -1;
  71 static int hf_bpdu_msg_age = -1;
  72 static int hf_bpdu_max_age = -1;
  73 static int hf_bpdu_hello_time = -1;
  74 static int hf_bpdu_forward_delay = -1;
  75
  76 static gint ett_bpdu = -1;
  77
  78 void dissect_bpdu(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
  79       guint16 protocol_identifier;
  80       guint8  protocol_version_identifier;
  81       guint8  bpdu_type;
  82       guint8  flags;
  83       guint16 root_identifier_bridge_priority;
  84       gchar   *root_identifier_mac;
  85       guint32 root_path_cost;
  86       guint16 bridge_identifier_bridge_priority;
  87       gchar   *bridge_identifier_mac;
  88       guint16 port_identifier;
  89       double message_age;
  90       double max_age;
  91       double hello_time;
  92       double forward_delay;
  93
  94       proto_tree *bpdu_tree;
  95       proto_item *ti;
  96       const u_char *bpdu;
  97
  98       bpdu = pd + offset;
  99       bpdu_type = (guint8) bpdu[BPDU_TYPE];
 100       flags = (guint8) bpdu[BPDU_FLAGS];
 101       root_identifier_bridge_priority = pntohs(bpdu + BPDU_ROOT_IDENTIFIER);
 102       root_identifier_mac = ether_to_str(bpdu + BPDU_ROOT_IDENTIFIER + 2);
 103       root_path_cost = pntohl(bpdu + BPDU_ROOT_PATH_COST);
 104       port_identifier = pntohs(bpdu + BPDU_PORT_IDENTIFIER);
 105
 106       if (check_col(fd, COL_PROTOCOL)) {
 107             col_add_str(fd, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
 108       }
 109
 110       if (check_col(fd, COL_INFO)) {
 111             if (bpdu_type == 0)
 112                   col_add_fstr(fd, COL_INFO, "Conf. %sRoot = %d/%s  Cost = %d  Port = 0x%04x",
 113                                flags & 0x1 ? "TC + " : "",
 114                                root_identifier_bridge_priority, root_identifier_mac, root_path_cost,
 115                                port_identifier);
 116             else if (bpdu_type == 0x80)
 117                   col_add_fstr(fd, COL_INFO, "Topology Change Notification");
 118       }
 119
 120       if (tree) {
 121             protocol_identifier = pntohs(bpdu + BPDU_IDENTIFIER);
 122             protocol_version_identifier = (guint8) bpdu[BPDU_VERSION_IDENTIFIER];
 123
 124             ti = proto_tree_add_protocol_format(tree, proto_bpdu, offset, 35,
 125                                 "Spanning Tree Protocol");
 126             bpdu_tree = proto_item_add_subtree(ti, ett_bpdu);
 127             proto_tree_add_uint_format(bpdu_tree, hf_bpdu_proto_id,
 128                                        offset + BPDU_IDENTIFIER, 2,
 129                                        protocol_identifier,
 130                                        "Protocol Identifier: 0x%04x (%s)",
 131                                        protocol_identifier,
 132                                        protocol_identifier == 0 ?
 133                                        "Spanning Tree" : "Unknown Protocol");
 134
 135             proto_tree_add_item(bpdu_tree, hf_bpdu_version_id,
 136                                 offset + BPDU_VERSION_IDENTIFIER, 1,
 137                                 protocol_version_identifier);
 138             if (protocol_version_identifier != 0)
 139                   proto_tree_add_text(bpdu_tree, offset + BPDU_VERSION_IDENTIFIER, 1, "   (Warning: this version of packet-bpdu only knows about version = 0)");
 140             proto_tree_add_uint_format(bpdu_tree, hf_bpdu_type,
 141                                        offset + BPDU_TYPE, 1,
 142                                        bpdu_type,
 143                                        "BPDU Type: 0x%02x (%s)",
 144                                        bpdu_type,
 145                                        bpdu_type == 0 ? "Configuration" :
 146                                        bpdu_type == 0x80 ? "Topology Change Notification" : "Unknown");
 147
 148             if (bpdu_type != 0) {
 149               dissect_data(pd, offset + BPDU_TYPE + 1, fd, tree);
 150               return;
 151             }
 152
 153             bridge_identifier_bridge_priority = pntohs(bpdu + BPDU_BRIDGE_IDENTIFIER);
 154             bridge_identifier_mac = ether_to_str(bpdu + BPDU_BRIDGE_IDENTIFIER + 2);
 155             message_age = pntohs(bpdu + BPDU_MESSAGE_AGE) / 256.0;
 156             max_age = pntohs(bpdu + BPDU_MAX_AGE) / 256.0;
 157             hello_time = pntohs(bpdu + BPDU_HELLO_TIME) / 256.0;
 158             forward_delay = pntohs(bpdu + BPDU_FORWARD_DELAY) / 256.0;
 159
 160             proto_tree_add_item(bpdu_tree, hf_bpdu_flags,
 161                                 offset + BPDU_FLAGS, 1, flags);
 162             if (flags & 0x80)
 163                   proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "   1... ....  Topology Change Acknowledgment");
 164             if (flags & 0x01)
 165                   proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "   .... ...1  Topology Change");
 166
 167             proto_tree_add_item_hidden(bpdu_tree, hf_bpdu_root_mac,
 168                                        offset + BPDU_ROOT_IDENTIFIER + 2, 6,
 169                                        bpdu + BPDU_ROOT_IDENTIFIER + 2);
 170             proto_tree_add_text(bpdu_tree,
 171                                 offset + BPDU_ROOT_IDENTIFIER, 8,
 172                                 "Root Identifier: %d / %s",
 173                                 root_identifier_bridge_priority,
 174                                 root_identifier_mac);
 175             proto_tree_add_item(bpdu_tree, hf_bpdu_root_cost,
 176                                 offset + BPDU_ROOT_PATH_COST, 4,
 177                                 root_path_cost);
 178             proto_tree_add_text(bpdu_tree,
 179                                 offset + BPDU_BRIDGE_IDENTIFIER, 8,
 180                                 "Bridge Identifier: %d / %s",
 181                                 bridge_identifier_bridge_priority,
 182                                 bridge_identifier_mac);
 183             proto_tree_add_item_hidden(bpdu_tree, hf_bpdu_bridge_mac,
 184                                        offset + BPDU_BRIDGE_IDENTIFIER + 2, 6,
 185                                        bpdu + BPDU_BRIDGE_IDENTIFIER + 2);
 186             proto_tree_add_item(bpdu_tree, hf_bpdu_port_id,
 187                                 offset + BPDU_PORT_IDENTIFIER, 2,
 188                                 port_identifier);
 189             proto_tree_add_item(bpdu_tree, hf_bpdu_msg_age,
 190                                 offset + BPDU_MESSAGE_AGE, 2,
 191                                 message_age);
 192             proto_tree_add_item(bpdu_tree, hf_bpdu_max_age,
 193                                 offset + BPDU_MAX_AGE, 2,
 194                                 max_age);
 195             proto_tree_add_item(bpdu_tree, hf_bpdu_hello_time,
 196                                 offset + BPDU_HELLO_TIME, 2,
 197                                 hello_time);
 198             proto_tree_add_item(bpdu_tree, hf_bpdu_forward_delay,
 199                                 offset + BPDU_FORWARD_DELAY, 2,
 200                                 forward_delay);
 201       }
 202 }
 203
 204 void
 205 proto_register_bpdu(void)
 206 {
 207
 208   static hf_register_info hf[] = {
 209     { &hf_bpdu_proto_id,
 210       { "Protocol Identifier",          "stp.protocol",
 211         FT_UINT16,      BASE_HEX,       NULL,   0x0,
 212         "" }},
 213     { &hf_bpdu_version_id,
 214       { "Protocol Version Identifier",  "stp.version",
 215         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 216         "" }},
 217     { &hf_bpdu_type,
 218       { "BPDU type",                    "stp.type",
 219         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 220         "" }},
 221     { &hf_bpdu_flags,
 222       { "BPDU flags",                   "stp.flags",
 223         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 224         "" }},
 225     { &hf_bpdu_root_mac,
 226       { "Root Identifier",              "stp.root.hw",
 227         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 228         "" }},
 229     { &hf_bpdu_root_cost,
 230       { "Root Path Cost",               "stp.root.cost",
 231         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 232         "" }},
 233     { &hf_bpdu_bridge_mac,
 234       { "Bridge Identifier",            "stp.bridge.hw",
 235         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 236         ""}},
 237     { &hf_bpdu_port_id,
 238       { "Port identifier",              "stp.port",
 239         FT_UINT16,      BASE_HEX,       NULL,   0x0,
 240         ""}},
 241     { &hf_bpdu_msg_age,
 242       { "Message Age",                  "stp.msg_age",
 243         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 244         "" }},
 245     { &hf_bpdu_max_age,
 246       { "Max Age",                      "stp.max_age",
 247         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 248         "" }},
 249     { &hf_bpdu_hello_time,
 250       { "Hello Time",                   "stp.hello",
 251         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 252         "" }},
 253     { &hf_bpdu_forward_delay,
 254       { "Forward Delay",                "stp.forward",
 255         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 256         "" }},
 257   };
 258   static gint *ett[] = {
 259     &ett_bpdu,
 260   };
 261
 262   proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "stp");
 263   proto_register_field_array(proto_bpdu, hf, array_length(hf));
 264   proto_register_subtree_array(ett, array_length(ett));
 265 }
 266
 267 void
 268 proto_reg_handoff_bpdu(void)
 269 {
 270   dissector_add("llc.dsap", SAP_BPDU, dissect_bpdu);
 271 }