packet-bpdu.c

   1 /* packet-bpdu.c
   2  * Routines for BPDU (Spanning Tree Protocol) disassembly
   3  *
   4  * $Id: packet-bpdu.c,v 1.7 2000/01/16 02:54:44 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 "resolv.h"
  45
  46 /* Offsets of fields within a BPDU */
  47
  48 #define BPDU_IDENTIFIER          0
  49 #define BPDU_VERSION_IDENTIFIER  2
  50 #define BPDU_TYPE                3
  51 #define BPDU_FLAGS               4
  52 #define BPDU_ROOT_IDENTIFIER     5
  53 #define BPDU_ROOT_PATH_COST     13
  54 #define BPDU_BRIDGE_IDENTIFIER  17
  55 #define BPDU_PORT_IDENTIFIER    25
  56 #define BPDU_MESSAGE_AGE        27
  57 #define BPDU_MAX_AGE            29
  58 #define BPDU_HELLO_TIME         31
  59 #define BPDU_FORWARD_DELAY      33
  60
  61 static int proto_bpdu = -1;
  62 static int hf_bpdu_proto_id = -1;
  63 static int hf_bpdu_version_id = -1;
  64 static int hf_bpdu_type = -1;
  65 static int hf_bpdu_flags = -1;
  66 static int hf_bpdu_root_mac = -1;
  67 static int hf_bpdu_root_cost = -1;
  68 static int hf_bpdu_bridge_mac = -1;
  69 static int hf_bpdu_port_id = -1;
  70 static int hf_bpdu_msg_age = -1;
  71 static int hf_bpdu_max_age = -1;
  72 static int hf_bpdu_hello_time = -1;
  73 static int hf_bpdu_forward_delay = -1;
  74
  75 static gint ett_bpdu = -1;
  76
  77 void dissect_bpdu(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
  78       guint16 protocol_identifier;
  79       guint8  protocol_version_identifier;
  80       guint8  bpdu_type;
  81       guint8  flags;
  82       guint16 root_identifier_bridge_priority;
  83       gchar   *root_identifier_mac;
  84       guint32 root_path_cost;
  85       guint16 bridge_identifier_bridge_priority;
  86       gchar   *bridge_identifier_mac;
  87       guint16 port_identifier;
  88       double message_age;
  89       double max_age;
  90       double hello_time;
  91       double forward_delay;
  92
  93       proto_tree *bpdu_tree;
  94       proto_item *ti;
  95       const u_char *bpdu;
  96
  97       bpdu = pd + offset;
  98       bpdu_type = (guint8) bpdu[BPDU_TYPE];
  99       flags = (guint8) bpdu[BPDU_FLAGS];
 100       root_identifier_bridge_priority = pntohs(bpdu + BPDU_ROOT_IDENTIFIER);
 101       root_identifier_mac = ether_to_str(bpdu + BPDU_ROOT_IDENTIFIER + 2);
 102       root_path_cost = pntohl(bpdu + BPDU_ROOT_PATH_COST);
 103       port_identifier = pntohs(bpdu + BPDU_PORT_IDENTIFIER);
 104
 105       if (check_col(fd, COL_PROTOCOL)) {
 106             col_add_str(fd, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
 107       }
 108
 109       if (check_col(fd, COL_INFO)) {
 110             if (bpdu_type == 0)
 111                   col_add_fstr(fd, COL_INFO, "Conf. %sRoot = %d/%s  Cost = %d  Port = 0x%04x",
 112                                flags & 0x1 ? "TC + " : "",
 113                                root_identifier_bridge_priority, root_identifier_mac, root_path_cost,
 114                                port_identifier);
 115             else if (bpdu_type == 0x80)
 116                   col_add_fstr(fd, COL_INFO, "Topology Change Notification");
 117       }
 118
 119       if (tree) {
 120             protocol_identifier = pntohs(bpdu + BPDU_IDENTIFIER);
 121             protocol_version_identifier = (guint8) bpdu[BPDU_VERSION_IDENTIFIER];
 122
 123             ti = proto_tree_add_item_format(tree, proto_bpdu, offset, 35, NULL, "Spanning Tree Protocol");
 124             bpdu_tree = proto_item_add_subtree(ti, ett_bpdu);
 125             proto_tree_add_item_format(bpdu_tree, hf_bpdu_proto_id,
 126                                        offset + BPDU_IDENTIFIER, 2,
 127                                        protocol_identifier,
 128                                        "Protocol Identifier: 0x%04x (%s)",
 129                                        protocol_identifier,
 130                                        protocol_identifier == 0 ?
 131                                        "Spanning Tree" : "Unknown Protocol");
 132
 133             proto_tree_add_item(bpdu_tree, hf_bpdu_version_id,
 134                                 offset + BPDU_VERSION_IDENTIFIER, 1,
 135                                 protocol_version_identifier);
 136             if (protocol_version_identifier != 0)
 137                   proto_tree_add_text(bpdu_tree, offset + BPDU_VERSION_IDENTIFIER, 1, "   (Warning: this version of packet-bpdu only knows about version = 0)");
 138             proto_tree_add_item_format(bpdu_tree, hf_bpdu_type,
 139                                        offset + BPDU_TYPE, 1,
 140                                        bpdu_type,
 141                                        "BPDU Type: 0x%02x (%s)",
 142                                        bpdu_type,
 143                                        bpdu_type == 0 ? "Configuration" :
 144                                        bpdu_type == 0x80 ? "Topology Change Notification" : "Unknown");
 145
 146             if (bpdu_type != 0) {
 147               dissect_data(pd, offset + BPDU_TYPE + 1, fd, tree);
 148               return;
 149             }
 150
 151             bridge_identifier_bridge_priority = pntohs(bpdu + BPDU_BRIDGE_IDENTIFIER);
 152             bridge_identifier_mac = ether_to_str(bpdu + BPDU_BRIDGE_IDENTIFIER + 2);
 153             message_age = pntohs(bpdu + BPDU_MESSAGE_AGE) / 256.0;
 154             max_age = pntohs(bpdu + BPDU_MAX_AGE) / 256.0;
 155             hello_time = pntohs(bpdu + BPDU_HELLO_TIME) / 256.0;
 156             forward_delay = pntohs(bpdu + BPDU_FORWARD_DELAY) / 256.0;
 157
 158             proto_tree_add_item(bpdu_tree, hf_bpdu_flags,
 159                                 offset + BPDU_FLAGS, 1, flags);
 160             if (flags & 0x80)
 161                   proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "   1... ....  Topology Change Acknowledgment");
 162             if (flags & 0x01)
 163                   proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "   .... ...1  Topology Change");
 164
 165             proto_tree_add_item_hidden(bpdu_tree, hf_bpdu_root_mac,
 166                                        offset + BPDU_ROOT_IDENTIFIER + 2, 6,
 167                                        bpdu + BPDU_ROOT_IDENTIFIER + 2);
 168             proto_tree_add_text(bpdu_tree,
 169                                 offset + BPDU_ROOT_IDENTIFIER, 8,
 170                                 "Root Identifier: %d / %s",
 171                                 root_identifier_bridge_priority,
 172                                 root_identifier_mac);
 173             proto_tree_add_item(bpdu_tree, hf_bpdu_root_cost,
 174                                 offset + BPDU_ROOT_PATH_COST, 4,
 175                                 root_path_cost);
 176             proto_tree_add_text(bpdu_tree,
 177                                 offset + BPDU_BRIDGE_IDENTIFIER, 8,
 178                                 "Bridge Identifier: %d / %s",
 179                                 bridge_identifier_bridge_priority,
 180                                 bridge_identifier_mac);
 181             proto_tree_add_item_hidden(bpdu_tree, hf_bpdu_bridge_mac,
 182                                        offset + BPDU_BRIDGE_IDENTIFIER + 2, 6,
 183                                        bpdu + BPDU_BRIDGE_IDENTIFIER + 2);
 184             proto_tree_add_item(bpdu_tree, hf_bpdu_port_id,
 185                                 offset + BPDU_PORT_IDENTIFIER, 2,
 186                                 port_identifier);
 187             proto_tree_add_item(bpdu_tree, hf_bpdu_msg_age,
 188                                 offset + BPDU_MESSAGE_AGE, 2,
 189                                 message_age);
 190             proto_tree_add_item(bpdu_tree, hf_bpdu_max_age,
 191                                 offset + BPDU_MAX_AGE, 2,
 192                                 max_age);
 193             proto_tree_add_item(bpdu_tree, hf_bpdu_hello_time,
 194                                 offset + BPDU_HELLO_TIME, 2,
 195                                 hello_time);
 196             proto_tree_add_item(bpdu_tree, hf_bpdu_forward_delay,
 197                                 offset + BPDU_FORWARD_DELAY, 2,
 198                                 forward_delay);
 199       }
 200 }
 201
 202 void
 203 proto_register_bpdu(void)
 204 {
 205
 206   static hf_register_info hf[] = {
 207     { &hf_bpdu_proto_id,
 208       { "Protocol Identifier",          "stp.protocol",
 209         FT_UINT16,      BASE_HEX,       NULL,   0x0,
 210         "" }},
 211     { &hf_bpdu_version_id,
 212       { "Protocol Version Identifier",  "stp.version",
 213         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 214         "" }},
 215     { &hf_bpdu_type,
 216       { "BPDU type",                    "stp.type",
 217         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 218         "" }},
 219     { &hf_bpdu_flags,
 220       { "BPDU flags",                   "stp.flags",
 221         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 222         "" }},
 223     { &hf_bpdu_root_mac,
 224       { "Root Identifier",              "stp.root.hw",
 225         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 226         "" }},
 227     { &hf_bpdu_root_cost,
 228       { "Root Path Cost",               "stp.root.cost",
 229         FT_UINT32,      BASE_DEC,       NULL,   0x0,
 230         "" }},
 231     { &hf_bpdu_bridge_mac,
 232       { "Bridge Identifier",            "stp.bridge.hw",
 233         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 234         ""}},
 235     { &hf_bpdu_port_id,
 236       { "Port identifier",              "stp.port",
 237         FT_UINT16,      BASE_HEX,       NULL,   0x0,
 238         ""}},
 239     { &hf_bpdu_msg_age,
 240       { "Message Age",                  "stp.msg_age",
 241         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 242         "" }},
 243     { &hf_bpdu_max_age,
 244       { "Max Age",                      "stp.max_age",
 245         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 246         "" }},
 247     { &hf_bpdu_hello_time,
 248       { "Hello Time",                   "stp.hello",
 249         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 250         "" }},
 251     { &hf_bpdu_forward_delay,
 252       { "Forward Delay",                "stp.forward",
 253         FT_DOUBLE,      BASE_NONE,      NULL,   0x0,
 254         "" }},
 255   };
 256   static gint *ett[] = {
 257     &ett_bpdu,
 258   };
 259
 260   proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "stp");
 261   proto_register_field_array(proto_bpdu, hf, array_length(hf));
 262   proto_register_subtree_array(ett, array_length(ett));
 263 }