epan/dissectors/packet-dec-bpdu.c

   1 /* packet-dec-bpdu.c
   2  * Routines for DEC BPDU (DEC Spanning Tree Protocol) disassembly
   3  *
   4  * $Id$
   5  *
   6  * Copyright 2001 Paul Ionescu <paul@acorp.ro>
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #include <glib.h>
  30 #include <epan/packet.h>
  31 #include <epan/addr_resolv.h>
  32 #include <epan/etypes.h>
  33 #include <epan/ppptypes.h>
  34
  35 /* Offsets of fields within a BPDU */
  36
  37 #define BPDU_DEC_CODE            0
  38 #define BPDU_TYPE                1
  39 #define BPDU_VERSION             2
  40 #define BPDU_FLAGS               3
  41 #define BPDU_ROOT_PRI            4
  42 #define BPDU_ROOT_MAC            6
  43 #define BPDU_ROOT_PATH_COST     12
  44 #define BPDU_BRIDGE_PRI         14
  45 #define BPDU_BRIDGE_MAC         16
  46 #define BPDU_PORT_IDENTIFIER    22
  47 #define BPDU_MESSAGE_AGE        23
  48 #define BPDU_HELLO_TIME         24
  49 #define BPDU_MAX_AGE            25
  50 #define BPDU_FORWARD_DELAY      26
  51
  52 #define DEC_BPDU_SIZE           27
  53
  54 /* Flag bits */
  55
  56 #define BPDU_FLAGS_SHORT_TIMERS         0x80
  57 #define BPDU_FLAGS_TCACK                0x02
  58 #define BPDU_FLAGS_TC                   0x01
  59
  60 void proto_register_dec_bpdu(void);
  61 void proto_reg_handoff_dec_bpdu(void);
  62
  63 static int proto_dec_bpdu = -1;
  64 static int hf_dec_bpdu_proto_id = -1;
  65 static int hf_dec_bpdu_type = -1;
  66 static int hf_dec_bpdu_version_id = -1;
  67 static int hf_dec_bpdu_flags = -1;
  68 static int hf_dec_bpdu_flags_short_timers = -1;
  69 static int hf_dec_bpdu_flags_tcack = -1;
  70 static int hf_dec_bpdu_flags_tc = -1;
  71 static int hf_dec_bpdu_root_pri = -1;
  72 static int hf_dec_bpdu_root_mac = -1;
  73 static int hf_dec_bpdu_root_cost = -1;
  74 static int hf_dec_bpdu_bridge_pri = -1;
  75 static int hf_dec_bpdu_bridge_mac = -1;
  76 static int hf_dec_bpdu_port_id = -1;
  77 static int hf_dec_bpdu_msg_age = -1;
  78 static int hf_dec_bpdu_hello_time = -1;
  79 static int hf_dec_bpdu_max_age = -1;
  80 static int hf_dec_bpdu_forward_delay = -1;
  81
  82 static gint ett_dec_bpdu = -1;
  83 static gint ett_dec_bpdu_flags = -1;
  84
  85 static const value_string protocol_id_vals[] = {
  86     { 0xe1, "DEC Spanning Tree Protocol" },
  87     { 0,    NULL }
  88 };
  89
  90 #define BPDU_TYPE_TOPOLOGY_CHANGE       2
  91 #define BPDU_TYPE_HELLO                 25
  92
  93 static const value_string bpdu_type_vals[] = {
  94     { BPDU_TYPE_TOPOLOGY_CHANGE, "Topology Change Notification" },
  95     { BPDU_TYPE_HELLO,           "Hello Packet" },
  96     { 0,                         NULL }
  97 };
  98
  99 static const char initial_sep[] = " (";
 100 static const char cont_sep[] = ", ";
 101
 102 #define APPEND_BOOLEAN_FLAG(flag, item, string)         \
 103     if(flag){                                           \
 104         if(item)                                        \
 105             proto_item_append_text(item, string, sep);  \
 106         sep = cont_sep;                                 \
 107     }
 108
 109 static void
 110 dissect_dec_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 111 {
 112     guint8  bpdu_type;
 113     guint8  flags;
 114     proto_tree *bpdu_tree;
 115     proto_tree *flags_tree;
 116     proto_item *ti;
 117     const char *sep;
 118
 119     col_set_str(pinfo->cinfo, COL_PROTOCOL, "DEC_STP");
 120     col_clear(pinfo->cinfo, COL_INFO);
 121
 122     bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
 123
 124     col_add_str(pinfo->cinfo, COL_INFO,
 125                 val_to_str(bpdu_type, bpdu_type_vals,
 126                            "Unknown BPDU type (%u)"));
 127
 128     set_actual_length(tvb, DEC_BPDU_SIZE);
 129
 130     if (tree) {
 131         ti = proto_tree_add_item(tree, proto_dec_bpdu, tvb, 0, DEC_BPDU_SIZE,
 132                                  ENC_NA);
 133         bpdu_tree = proto_item_add_subtree(ti, ett_dec_bpdu);
 134
 135         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_proto_id, tvb,
 136                             BPDU_DEC_CODE, 1, ENC_BIG_ENDIAN);
 137
 138         proto_tree_add_uint(bpdu_tree, hf_dec_bpdu_type, tvb,
 139                             BPDU_TYPE, 1, bpdu_type);
 140
 141         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_version_id, tvb,
 142                             BPDU_VERSION, 1, ENC_BIG_ENDIAN);
 143
 144         flags = tvb_get_guint8(tvb, BPDU_FLAGS);
 145         ti = proto_tree_add_uint(bpdu_tree, hf_dec_bpdu_flags, tvb,
 146                                  BPDU_FLAGS, 1, flags);
 147         flags_tree = proto_item_add_subtree(ti, ett_dec_bpdu_flags);
 148         sep = initial_sep;
 149         APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_SHORT_TIMERS, ti,
 150                             "%sUse short timers");
 151         proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_short_timers, tvb,
 152                                BPDU_FLAGS, 1, flags);
 153         APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TCACK, ti,
 154                             "%sTopology Change Acknowledgment");
 155         proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_tcack, tvb,
 156                                BPDU_FLAGS, 1, flags);
 157         APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TC, ti,
 158                             "%sTopology Change");
 159         proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_tc, tvb,
 160                                BPDU_FLAGS, 1, flags);
 161         if (sep != initial_sep) {
 162             /* We put something in; put in the terminating ")" */
 163             proto_item_append_text(ti, ")");
 164         }
 165
 166         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_pri, tvb,
 167                             BPDU_ROOT_PRI, 2, ENC_BIG_ENDIAN);
 168         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_mac, tvb,
 169                             BPDU_ROOT_MAC, 6, ENC_NA);
 170         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_cost, tvb,
 171                             BPDU_ROOT_PATH_COST, 2, ENC_BIG_ENDIAN);
 172         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_pri, tvb,
 173                             BPDU_BRIDGE_PRI, 2, ENC_BIG_ENDIAN);
 174         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_mac, tvb,
 175                             BPDU_BRIDGE_MAC, 6, ENC_NA);
 176         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_port_id, tvb,
 177                             BPDU_PORT_IDENTIFIER, 1, ENC_BIG_ENDIAN);
 178         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_msg_age, tvb,
 179                             BPDU_MESSAGE_AGE, 1, ENC_BIG_ENDIAN);
 180         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_hello_time, tvb,
 181                             BPDU_HELLO_TIME, 1, ENC_BIG_ENDIAN);
 182         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_max_age, tvb,
 183                             BPDU_MAX_AGE, 1, ENC_BIG_ENDIAN);
 184         proto_tree_add_item(bpdu_tree, hf_dec_bpdu_forward_delay, tvb,
 185                             BPDU_FORWARD_DELAY, 1, ENC_BIG_ENDIAN);
 186
 187     }
 188 }
 189
 190 void
 191 proto_register_dec_bpdu(void)
 192 {
 193
 194     static hf_register_info hf[] = {
 195         { &hf_dec_bpdu_proto_id,
 196           { "Protocol Identifier",          "dec_stp.protocol",
 197             FT_UINT8,       BASE_HEX,       VALS(protocol_id_vals), 0x0,
 198             NULL, HFILL }},
 199         { &hf_dec_bpdu_type,
 200           { "BPDU Type",                    "dec_stp.type",
 201             FT_UINT8,       BASE_DEC,       VALS(bpdu_type_vals),   0x0,
 202             NULL, HFILL }},
 203         { &hf_dec_bpdu_version_id,
 204           { "BPDU Version",                 "dec_stp.version",
 205             FT_UINT8,       BASE_DEC,       NULL,   0x0,
 206             NULL, HFILL }},
 207         { &hf_dec_bpdu_flags,
 208           { "BPDU flags",                   "dec_stp.flags",
 209             FT_UINT8,       BASE_HEX,       NULL,   0x0,
 210             NULL, HFILL }},
 211         { &hf_dec_bpdu_flags_short_timers,
 212           { "Use short timers",             "dec_stp.flags.short_timers",
 213             FT_BOOLEAN,     8,              TFS(&tfs_yes_no),       BPDU_FLAGS_SHORT_TIMERS,
 214             NULL, HFILL }},
 215         { &hf_dec_bpdu_flags_tcack,
 216           { "Topology Change Acknowledgment",  "dec_stp.flags.tcack",
 217             FT_BOOLEAN,     8,              TFS(&tfs_yes_no),       BPDU_FLAGS_TCACK,
 218             NULL, HFILL }},
 219         { &hf_dec_bpdu_flags_tc,
 220           { "Topology Change",              "dec_stp.flags.tc",
 221             FT_BOOLEAN,     8,              TFS(&tfs_yes_no),       BPDU_FLAGS_TC,
 222             NULL, HFILL }},
 223         { &hf_dec_bpdu_root_pri,
 224           { "Root Priority",                "dec_stp.root.pri",
 225             FT_UINT16,      BASE_DEC,       NULL,   0x0,
 226             NULL, HFILL }},
 227         { &hf_dec_bpdu_root_mac,
 228           { "Root MAC",                     "dec_stp.root.mac",
 229             FT_ETHER,       BASE_NONE,      NULL,   0x0,
 230             NULL, HFILL }},
 231         { &hf_dec_bpdu_root_cost,
 232           { "Root Path Cost",               "dec_stp.root.cost",
 233             FT_UINT16,      BASE_DEC,       NULL,   0x0,
 234             NULL, HFILL }},
 235         { &hf_dec_bpdu_bridge_pri,
 236           { "Bridge Priority",              "dec_stp.bridge.pri",
 237             FT_UINT16,      BASE_DEC,       NULL,   0x0,
 238             NULL, HFILL }},
 239         { &hf_dec_bpdu_bridge_mac,
 240           { "Bridge MAC",                   "dec_stp.bridge.mac",
 241             FT_ETHER,       BASE_NONE,      NULL,   0x0,
 242             NULL, HFILL }},
 243         { &hf_dec_bpdu_port_id,
 244           { "Port identifier",              "dec_stp.port",
 245             FT_UINT8,       BASE_DEC,       NULL,   0x0,
 246             NULL, HFILL }},
 247         { &hf_dec_bpdu_msg_age,
 248           { "Message Age",                  "dec_stp.msg_age",
 249             FT_UINT8,       BASE_DEC,       NULL,   0x0,
 250             NULL, HFILL }},
 251         { &hf_dec_bpdu_hello_time,
 252           { "Hello Time",                   "dec_stp.hello",
 253             FT_UINT8,       BASE_DEC,       NULL,   0x0,
 254             NULL, HFILL }},
 255         { &hf_dec_bpdu_max_age,
 256           { "Max Age",                      "dec_stp.max_age",
 257             FT_UINT8,       BASE_DEC,       NULL,   0x0,
 258             NULL, HFILL }},
 259         { &hf_dec_bpdu_forward_delay,
 260           { "Forward Delay",                "dec_stp.forward",
 261             FT_UINT8,       BASE_DEC,       NULL,   0x0,
 262             NULL, HFILL }},
 263     };
 264     static gint *ett[] = {
 265         &ett_dec_bpdu,
 266         &ett_dec_bpdu_flags,
 267     };
 268
 269     proto_dec_bpdu = proto_register_protocol("DEC Spanning Tree Protocol",
 270                                              "DEC_STP", "dec_stp");
 271     proto_register_field_array(proto_dec_bpdu, hf, array_length(hf));
 272     proto_register_subtree_array(ett, array_length(ett));
 273 }
 274
 275 void
 276 proto_reg_handoff_dec_bpdu(void)
 277 {
 278     dissector_handle_t dec_bpdu_handle;
 279
 280     dec_bpdu_handle = create_dissector_handle(dissect_dec_bpdu,
 281                                               proto_dec_bpdu);
 282     dissector_add_uint("ethertype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 283     dissector_add_uint("chdlc.protocol", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 284     dissector_add_uint("ppp.protocol", PPP_DEC_LB, dec_bpdu_handle);
 285 }