packet-dec-bpdu.c

   1 /* packet-dec-bpdu.c
   2  * Routines for DEC BPDU (DEC Spanning Tree Protocol) disassembly
   3  *
   4  * $Id: packet-dec-bpdu.c,v 1.15 2002/08/28 21:00:12 jmayer Exp $
   5  *
   6  * Copyright 2001 Paul Ionescu <paul@acorp.ro>
   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 <epan/resolv.h>
  36 #include "etypes.h"
  37 #include "ppptypes.h"
  38
  39 /* Offsets of fields within a BPDU */
  40
  41 #define BPDU_DEC_CODE            0
  42 #define BPDU_TYPE                1
  43 #define BPDU_VERSION             2
  44 #define BPDU_FLAGS               3
  45 #define BPDU_ROOT_PRI            4
  46 #define BPDU_ROOT_MAC            6
  47 #define BPDU_ROOT_PATH_COST     12
  48 #define BPDU_BRIDGE_PRI         14
  49 #define BPDU_BRIDGE_MAC         16
  50 #define BPDU_PORT_IDENTIFIER    22
  51 #define BPDU_MESSAGE_AGE        23
  52 #define BPDU_HELLO_TIME         24
  53 #define BPDU_MAX_AGE            25
  54 #define BPDU_FORWARD_DELAY      26
  55
  56 #define DEC_BPDU_SIZE           27
  57
  58 /* Flag bits */
  59
  60 #define BPDU_FLAGS_SHORT_TIMERS         0x80
  61 #define BPDU_FLAGS_TCACK                0x02
  62 #define BPDU_FLAGS_TC                   0x01
  63
  64 static int proto_dec_bpdu = -1;
  65 static int hf_dec_bpdu_proto_id = -1;
  66 static int hf_dec_bpdu_type = -1;
  67 static int hf_dec_bpdu_version_id = -1;
  68 static int hf_dec_bpdu_flags = -1;
  69 static int hf_dec_bpdu_flags_short_timers = -1;
  70 static int hf_dec_bpdu_flags_tcack = -1;
  71 static int hf_dec_bpdu_flags_tc = -1;
  72 static int hf_dec_bpdu_root_pri = -1;
  73 static int hf_dec_bpdu_root_mac = -1;
  74 static int hf_dec_bpdu_root_cost = -1;
  75 static int hf_dec_bpdu_bridge_pri = -1;
  76 static int hf_dec_bpdu_bridge_mac = -1;
  77 static int hf_dec_bpdu_port_id = -1;
  78 static int hf_dec_bpdu_msg_age = -1;
  79 static int hf_dec_bpdu_hello_time = -1;
  80 static int hf_dec_bpdu_max_age = -1;
  81 static int hf_dec_bpdu_forward_delay = -1;
  82
  83 static gint ett_dec_bpdu = -1;
  84 static gint ett_dec_bpdu_flags = -1;
  85
  86 static const value_string protocol_id_vals[] = {
  87         { 0xe1, "DEC Spanning Tree Protocol" },
  88         { 0,    NULL }
  89 };
  90
  91 #define BPDU_TYPE_TOPOLOGY_CHANGE       2
  92 #define BPDU_TYPE_HELLO                 25
  93
  94 static const value_string bpdu_type_vals[] = {
  95         { BPDU_TYPE_TOPOLOGY_CHANGE, "Topology Change Notification" },
  96         { BPDU_TYPE_HELLO,           "Hello Packet" },
  97         { 0,                         NULL }
  98 };
  99
 100 static const char initial_sep[] = " (";
 101 static const char cont_sep[] = ", ";
 102
 103 #define APPEND_BOOLEAN_FLAG(flag, item, string) \
 104         if(flag){                                                       \
 105                 if(item)                                                \
 106                         proto_item_append_text(item, string, sep);      \
 107                 sep = cont_sep;                                         \
 108         }
 109
 110 static void
 111 dissect_dec_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 112 {
 113       guint8  protocol_version;
 114       guint8  bpdu_type;
 115       guint8  flags;
 116       proto_tree *bpdu_tree;
 117       proto_tree *flags_tree;
 118       proto_item *ti;
 119       const char *sep;
 120
 121       if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 122             col_set_str(pinfo->cinfo, COL_PROTOCOL, "DEC_STP");
 123       }
 124       if (check_col(pinfo->cinfo, COL_INFO)) {
 125             col_clear(pinfo->cinfo, COL_INFO);
 126       }
 127
 128       bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
 129
 130       if (check_col(pinfo->cinfo, COL_INFO)) {
 131             col_add_str(pinfo->cinfo, COL_INFO,
 132                         val_to_str(bpdu_type, bpdu_type_vals,
 133                                    "Unknown BPDU type (%u)"));
 134       }
 135
 136       set_actual_length(tvb, DEC_BPDU_SIZE);
 137
 138       if (tree) {
 139             ti = proto_tree_add_item(tree, proto_dec_bpdu, tvb, 0, DEC_BPDU_SIZE,
 140                                 FALSE);
 141             bpdu_tree = proto_item_add_subtree(ti, ett_dec_bpdu);
 142
 143             protocol_version = tvb_get_guint8(tvb, BPDU_VERSION);
 144
 145             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_proto_id, tvb,
 146                                 BPDU_DEC_CODE, 1, FALSE);
 147
 148             proto_tree_add_uint(bpdu_tree, hf_dec_bpdu_type, tvb,
 149                                 BPDU_TYPE, 1, bpdu_type);
 150
 151             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_version_id, tvb,
 152                                 BPDU_VERSION, 1, FALSE);
 153
 154             flags = tvb_get_guint8(tvb, BPDU_FLAGS);
 155             ti = proto_tree_add_uint(bpdu_tree, hf_dec_bpdu_flags, tvb,
 156                                      BPDU_FLAGS, 1, flags);
 157             flags_tree = proto_item_add_subtree(ti, ett_dec_bpdu_flags);
 158             sep = initial_sep;
 159             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_SHORT_TIMERS, ti,
 160                                 "%sUse short timers");
 161             proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_short_timers, tvb,
 162                                    BPDU_FLAGS, 1, flags);
 163             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TCACK, ti,
 164                                 "%sTopology Change Acknowledgment");
 165             proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_tcack, tvb,
 166                                    BPDU_FLAGS, 1, flags);
 167             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TC, ti,
 168                                 "%sTopology Change");
 169             proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_tc, tvb,
 170                                    BPDU_FLAGS, 1, flags);
 171             if (sep != initial_sep) {
 172               /* We put something in; put in the terminating ")" */
 173               proto_item_append_text(ti, ")");
 174             }
 175
 176             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_pri, tvb,
 177                                 BPDU_ROOT_PRI, 2, FALSE);
 178             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_mac, tvb,
 179                                 BPDU_ROOT_MAC, 6, FALSE);
 180             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_cost, tvb,
 181                                 BPDU_ROOT_PATH_COST, 2, FALSE);
 182             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_pri, tvb,
 183                                 BPDU_BRIDGE_PRI, 2, FALSE);
 184             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_mac, tvb,
 185                                 BPDU_BRIDGE_MAC, 6, FALSE);
 186             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_port_id, tvb,
 187                                 BPDU_PORT_IDENTIFIER, 1, FALSE);
 188             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_msg_age, tvb,
 189                                 BPDU_MESSAGE_AGE, 1, FALSE);
 190             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_hello_time, tvb,
 191                                 BPDU_HELLO_TIME, 1, FALSE);
 192             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_max_age, tvb,
 193                                 BPDU_MAX_AGE, 1, FALSE);
 194             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_forward_delay, tvb,
 195                                 BPDU_FORWARD_DELAY, 1, FALSE);
 196
 197       }
 198 }
 199
 200 static const true_false_string yesno = {
 201         "Yes",
 202         "No"
 203 };
 204
 205 void
 206 proto_register_dec_bpdu(void)
 207 {
 208
 209   static hf_register_info hf[] = {
 210     { &hf_dec_bpdu_proto_id,
 211       { "Protocol Identifier",          "dec_stp.protocol",
 212         FT_UINT8,       BASE_HEX,       VALS(&protocol_id_vals), 0x0,
 213         "", HFILL }},
 214     { &hf_dec_bpdu_type,
 215       { "BPDU Type",                    "dec_stp.type",
 216         FT_UINT8,       BASE_DEC,       VALS(&bpdu_type_vals),  0x0,
 217         "", HFILL }},
 218     { &hf_dec_bpdu_version_id,
 219       { "BPDU Version",                 "dec_stp.version",
 220         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 221         "", HFILL }},
 222     { &hf_dec_bpdu_flags,
 223       { "BPDU flags",                   "dec_stp.flags",
 224         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 225         "", HFILL }},
 226     { &hf_dec_bpdu_flags_short_timers,
 227       { "Use short timers",             "dec_stp.flags.short_timers",
 228         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_SHORT_TIMERS,
 229         "", HFILL }},
 230     { &hf_dec_bpdu_flags_tcack,
 231       { "Topology Change Acknowledgment",  "dec_stp.flags.tcack",
 232         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TCACK,
 233         "", HFILL }},
 234     { &hf_dec_bpdu_flags_tc,
 235       { "Topology Change",              "dec_stp.flags.tc",
 236         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TC,
 237         "", HFILL }},
 238     { &hf_dec_bpdu_root_pri,
 239       { "Root Priority",                "dec_stp.root.pri",
 240         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 241         "", HFILL }},
 242     { &hf_dec_bpdu_root_mac,
 243       { "Root MAC",                     "dec_stp.root.mac",
 244         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 245         "", HFILL }},
 246     { &hf_dec_bpdu_root_cost,
 247       { "Root Path Cost",               "dec_stp.root.cost",
 248         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 249         "", HFILL }},
 250     { &hf_dec_bpdu_bridge_pri,
 251       { "Bridge Priority",              "dec_stp.bridge.pri",
 252         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 253         "", HFILL }},
 254     { &hf_dec_bpdu_bridge_mac,
 255       { "Bridge MAC",                   "dec_stp.bridge.mac",
 256         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 257         "", HFILL }},
 258     { &hf_dec_bpdu_port_id,
 259       { "Port identifier",              "dec_stp.port",
 260         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 261         "", HFILL }},
 262     { &hf_dec_bpdu_msg_age,
 263       { "Message Age",                  "dec_stp.msg_age",
 264         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 265         "", HFILL }},
 266     { &hf_dec_bpdu_hello_time,
 267       { "Hello Time",                   "dec_stp.hello",
 268         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 269         "", HFILL }},
 270     { &hf_dec_bpdu_max_age,
 271       { "Max Age",                      "dec_stp.max_age",
 272         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 273         "", HFILL }},
 274     { &hf_dec_bpdu_forward_delay,
 275       { "Forward Delay",                "dec_stp.forward",
 276         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 277         "", HFILL }},
 278   };
 279   static gint *ett[] = {
 280     &ett_dec_bpdu,
 281     &ett_dec_bpdu_flags,
 282   };
 283
 284   proto_dec_bpdu = proto_register_protocol("DEC Spanning Tree Protocol",
 285                                            "DEC_STP", "dec_stp");
 286   proto_register_field_array(proto_dec_bpdu, hf, array_length(hf));
 287   proto_register_subtree_array(ett, array_length(ett));
 288 }
 289
 290 void
 291 proto_reg_handoff_dec_bpdu(void)
 292 {
 293   dissector_handle_t dec_bpdu_handle;
 294
 295   dec_bpdu_handle = create_dissector_handle(dissect_dec_bpdu,
 296                                             proto_dec_bpdu);
 297   dissector_add("ethertype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 298   dissector_add("chdlctype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 299   dissector_add("ppp.protocol", PPP_DEC_LB, dec_bpdu_handle);
 300 }