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 1.13 2002/03/19 09:02:01 guy 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 #ifdef HAVE_SYS_TYPES_H
  32 # include <sys/types.h>
  33 #endif
  34
  35 #ifdef HAVE_NETINET_IN_H
  36 # include <netinet/in.h>
  37 #endif
  38
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <glib.h>
  42 #include <epan/packet.h>
  43 #include <epan/resolv.h>
  44 #include "etypes.h"
  45 #include "ppptypes.h"
  46
  47 /* Offsets of fields within a BPDU */
  48
  49 #define BPDU_DEC_CODE            0
  50 #define BPDU_TYPE                1
  51 #define BPDU_VERSION             2
  52 #define BPDU_FLAGS               3
  53 #define BPDU_ROOT_PRI            4
  54 #define BPDU_ROOT_MAC            6
  55 #define BPDU_ROOT_PATH_COST     12
  56 #define BPDU_BRIDGE_PRI         14
  57 #define BPDU_BRIDGE_MAC         16
  58 #define BPDU_PORT_IDENTIFIER    22
  59 #define BPDU_MESSAGE_AGE        23
  60 #define BPDU_HELLO_TIME         24
  61 #define BPDU_MAX_AGE            25
  62 #define BPDU_FORWARD_DELAY      26
  63
  64 #define DEC_BPDU_SIZE           27
  65
  66 /* Flag bits */
  67
  68 #define BPDU_FLAGS_SHORT_TIMERS         0x80
  69 #define BPDU_FLAGS_TCACK                0x02
  70 #define BPDU_FLAGS_TC                   0x01
  71
  72 static int proto_dec_bpdu = -1;
  73 static int hf_dec_bpdu_proto_id = -1;
  74 static int hf_dec_bpdu_type = -1;
  75 static int hf_dec_bpdu_version_id = -1;
  76 static int hf_dec_bpdu_flags = -1;
  77 static int hf_dec_bpdu_flags_short_timers = -1;
  78 static int hf_dec_bpdu_flags_tcack = -1;
  79 static int hf_dec_bpdu_flags_tc = -1;
  80 static int hf_dec_bpdu_root_pri = -1;
  81 static int hf_dec_bpdu_root_mac = -1;
  82 static int hf_dec_bpdu_root_cost = -1;
  83 static int hf_dec_bpdu_bridge_pri = -1;
  84 static int hf_dec_bpdu_bridge_mac = -1;
  85 static int hf_dec_bpdu_port_id = -1;
  86 static int hf_dec_bpdu_msg_age = -1;
  87 static int hf_dec_bpdu_hello_time = -1;
  88 static int hf_dec_bpdu_max_age = -1;
  89 static int hf_dec_bpdu_forward_delay = -1;
  90
  91 static gint ett_dec_bpdu = -1;
  92 static gint ett_dec_bpdu_flags = -1;
  93
  94 static const value_string protocol_id_vals[] = {
  95         { 0xe1, "DEC Spanning Tree Protocol" },
  96         { 0,    NULL }
  97 };
  98
  99 #define BPDU_TYPE_TOPOLOGY_CHANGE       2
 100 #define BPDU_TYPE_HELLO                 25
 101
 102 static const value_string bpdu_type_vals[] = {
 103         { BPDU_TYPE_TOPOLOGY_CHANGE, "Topology Change Notification" },
 104         { BPDU_TYPE_HELLO,           "Hello Packet" },
 105         { 0,                         NULL }
 106 };
 107
 108 static const char initial_sep[] = " (";
 109 static const char cont_sep[] = ", ";
 110
 111 #define APPEND_BOOLEAN_FLAG(flag, item, string) \
 112         if(flag){                                                       \
 113                 if(item)                                                \
 114                         proto_item_append_text(item, string, sep);      \
 115                 sep = cont_sep;                                         \
 116         }
 117
 118 static void
 119 dissect_dec_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 120 {
 121       guint8  protocol_version;
 122       guint8  bpdu_type;
 123       guint8  flags;
 124       proto_tree *bpdu_tree;
 125       proto_tree *flags_tree;
 126       proto_item *ti;
 127       const char *sep;
 128
 129       if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 130             col_set_str(pinfo->cinfo, COL_PROTOCOL, "DEC_STP");
 131       }
 132       if (check_col(pinfo->cinfo, COL_INFO)) {
 133             col_clear(pinfo->cinfo, COL_INFO);
 134       }
 135
 136       bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
 137
 138       if (check_col(pinfo->cinfo, COL_INFO)) {
 139             col_add_str(pinfo->cinfo, COL_INFO,
 140                         val_to_str(bpdu_type, bpdu_type_vals,
 141                                    "Unknown BPDU type (%u)"));
 142       }
 143
 144       set_actual_length(tvb, DEC_BPDU_SIZE);
 145
 146       if (tree) {
 147             ti = proto_tree_add_item(tree, proto_dec_bpdu, tvb, 0, DEC_BPDU_SIZE,
 148                                 FALSE);
 149             bpdu_tree = proto_item_add_subtree(ti, ett_dec_bpdu);
 150
 151             protocol_version = tvb_get_guint8(tvb, BPDU_VERSION);
 152
 153             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_proto_id, tvb,
 154                                 BPDU_DEC_CODE, 1, FALSE);
 155
 156             proto_tree_add_uint(bpdu_tree, hf_dec_bpdu_type, tvb,
 157                                 BPDU_TYPE, 1, bpdu_type);
 158
 159             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_version_id, tvb,
 160                                 BPDU_VERSION, 1, FALSE);
 161
 162             flags = tvb_get_guint8(tvb, BPDU_FLAGS);
 163             ti = proto_tree_add_uint(bpdu_tree, hf_dec_bpdu_flags, tvb,
 164                                      BPDU_FLAGS, 1, flags);
 165             flags_tree = proto_item_add_subtree(ti, ett_dec_bpdu_flags);
 166             sep = initial_sep;
 167             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_SHORT_TIMERS, ti,
 168                                 "%sUse short timers");
 169             proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_short_timers, tvb,
 170                                    BPDU_FLAGS, 1, flags);
 171             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TCACK, ti,
 172                                 "%sTopology Change Acknowledgment");
 173             proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_tcack, tvb,
 174                                    BPDU_FLAGS, 1, flags);
 175             APPEND_BOOLEAN_FLAG(flags & BPDU_FLAGS_TC, ti,
 176                                 "%sTopology Change");
 177             proto_tree_add_boolean(flags_tree, hf_dec_bpdu_flags_tc, tvb,
 178                                    BPDU_FLAGS, 1, flags);
 179             if (sep != initial_sep) {
 180               /* We put something in; put in the terminating ")" */
 181               proto_item_append_text(ti, ")");
 182             }
 183
 184             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_pri, tvb,
 185                                 BPDU_ROOT_PRI, 2, FALSE);
 186             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_mac, tvb,
 187                                 BPDU_ROOT_MAC, 6, FALSE);
 188             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_cost, tvb,
 189                                 BPDU_ROOT_PATH_COST, 2, FALSE);
 190             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_pri, tvb,
 191                                 BPDU_BRIDGE_PRI, 2, FALSE);
 192             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_mac, tvb,
 193                                 BPDU_BRIDGE_MAC, 6, FALSE);
 194             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_port_id, tvb,
 195                                 BPDU_PORT_IDENTIFIER, 1, FALSE);
 196             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_msg_age, tvb,
 197                                 BPDU_MESSAGE_AGE, 1, FALSE);
 198             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_hello_time, tvb,
 199                                 BPDU_HELLO_TIME, 1, FALSE);
 200             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_max_age, tvb,
 201                                 BPDU_MAX_AGE, 1, FALSE);
 202             proto_tree_add_item(bpdu_tree, hf_dec_bpdu_forward_delay, tvb,
 203                                 BPDU_FORWARD_DELAY, 1, FALSE);
 204
 205       }
 206 }
 207
 208 static const true_false_string yesno = {
 209         "Yes",
 210         "No"
 211 };
 212
 213 void
 214 proto_register_dec_bpdu(void)
 215 {
 216
 217   static hf_register_info hf[] = {
 218     { &hf_dec_bpdu_proto_id,
 219       { "Protocol Identifier",          "dec_stp.protocol",
 220         FT_UINT8,       BASE_HEX,       VALS(&protocol_id_vals), 0x0,
 221         "", HFILL }},
 222     { &hf_dec_bpdu_type,
 223       { "BPDU Type",                    "dec_stp.type",
 224         FT_UINT8,       BASE_DEC,       VALS(&bpdu_type_vals),  0x0,
 225         "", HFILL }},
 226     { &hf_dec_bpdu_version_id,
 227       { "BPDU Version",                 "dec_stp.version",
 228         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 229         "", HFILL }},
 230     { &hf_dec_bpdu_flags,
 231       { "BPDU flags",                   "dec_stp.flags",
 232         FT_UINT8,       BASE_HEX,       NULL,   0x0,
 233         "", HFILL }},
 234     { &hf_dec_bpdu_flags_short_timers,
 235       { "Use short timers",             "dec_stp.flags.short_timers",
 236         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_SHORT_TIMERS,
 237         "", HFILL }},
 238     { &hf_dec_bpdu_flags_tcack,
 239       { "Topology Change Acknowledgment",  "dec_stp.flags.tcack",
 240         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TCACK,
 241         "", HFILL }},
 242     { &hf_dec_bpdu_flags_tc,
 243       { "Topology Change",              "dec_stp.flags.tc",
 244         FT_BOOLEAN,     8,              TFS(&yesno),    BPDU_FLAGS_TC,
 245         "", HFILL }},
 246     { &hf_dec_bpdu_root_pri,
 247       { "Root Priority",                "dec_stp.root.pri",
 248         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 249         "", HFILL }},
 250     { &hf_dec_bpdu_root_mac,
 251       { "Root MAC",                     "dec_stp.root.mac",
 252         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 253         "", HFILL }},
 254     { &hf_dec_bpdu_root_cost,
 255       { "Root Path Cost",               "dec_stp.root.cost",
 256         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 257         "", HFILL }},
 258     { &hf_dec_bpdu_bridge_pri,
 259       { "Bridge Priority",              "dec_stp.bridge.pri",
 260         FT_UINT16,      BASE_DEC,       NULL,   0x0,
 261         "", HFILL }},
 262     { &hf_dec_bpdu_bridge_mac,
 263       { "Bridge MAC",                   "dec_stp.bridge.mac",
 264         FT_ETHER,       BASE_NONE,      NULL,   0x0,
 265         "", HFILL }},
 266     { &hf_dec_bpdu_port_id,
 267       { "Port identifier",              "dec_stp.port",
 268         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 269         "", HFILL }},
 270     { &hf_dec_bpdu_msg_age,
 271       { "Message Age",                  "dec_stp.msg_age",
 272         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 273         "", HFILL }},
 274     { &hf_dec_bpdu_hello_time,
 275       { "Hello Time",                   "dec_stp.hello",
 276         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 277         "", HFILL }},
 278     { &hf_dec_bpdu_max_age,
 279       { "Max Age",                      "dec_stp.max_age",
 280         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 281         "", HFILL }},
 282     { &hf_dec_bpdu_forward_delay,
 283       { "Forward Delay",                "dec_stp.forward",
 284         FT_UINT8,       BASE_DEC,       NULL,   0x0,
 285         "", HFILL }},
 286   };
 287   static gint *ett[] = {
 288     &ett_dec_bpdu,
 289     &ett_dec_bpdu_flags,
 290   };
 291
 292   proto_dec_bpdu = proto_register_protocol("DEC Spanning Tree Protocol",
 293                                            "DEC_STP", "dec_stp");
 294   proto_register_field_array(proto_dec_bpdu, hf, array_length(hf));
 295   proto_register_subtree_array(ett, array_length(ett));
 296 }
 297
 298 void
 299 proto_reg_handoff_dec_bpdu(void)
 300 {
 301   dissector_handle_t dec_bpdu_handle;
 302
 303   dec_bpdu_handle = create_dissector_handle(dissect_dec_bpdu,
 304                                             proto_dec_bpdu);
 305   dissector_add("ethertype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 306   dissector_add("chdlctype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 307   dissector_add("ppp.protocol", PPP_DEC_LB, dec_bpdu_handle);
 308 }