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 1.9 2001/12/10 00:25:27 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 "packet.h"
  43 #include "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
  67 static int proto_dec_bpdu = -1;
  68
  69 static gint ett_dec_bpdu = -1;
  70
  71 static void
  72 dissect_dec_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
  73       guint8  protocol_identifier;
  74       guint8  protocol_version;
  75       guint8  bpdu_type;
  76       guint8  flags;
  77       proto_tree *bpdu_tree;
  78       proto_item *ti;
  79
  80       if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
  81             col_set_str(pinfo->cinfo, COL_PROTOCOL, "DEC_STP");
  82       }
  83       if (check_col(pinfo->cinfo, COL_INFO)) {
  84             col_clear(pinfo->cinfo, COL_INFO);
  85       }
  86
  87       bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
  88       flags=tvb_get_guint8(tvb,BPDU_FLAGS);
  89
  90       if (check_col(pinfo->cinfo, COL_INFO)) {
  91             if (bpdu_type == 25)
  92                   col_add_fstr(pinfo->cinfo, COL_INFO, "Hello Packet");
  93             else if (bpdu_type == 0x02)
  94                   col_add_fstr(pinfo->cinfo, COL_INFO, "Topology Change Notification");
  95       }
  96
  97       tvb_set_reported_length(tvb, DEC_BPDU_SIZE);
  98
  99       if (tree) {
 100             protocol_identifier = tvb_get_guint8(tvb, BPDU_DEC_CODE);
 101
 102             protocol_version = tvb_get_guint8(tvb, BPDU_VERSION);
 103
 104             ti = proto_tree_add_protocol_format(tree, proto_dec_bpdu, tvb, 0, DEC_BPDU_SIZE,
 105                                 "DEC Spanning Tree Protocol");
 106             bpdu_tree = proto_item_add_subtree(ti, ett_dec_bpdu);
 107
 108             proto_tree_add_text(bpdu_tree, tvb, BPDU_DEC_CODE, 1, "Protocol ID: 0x%02x (%s)",
 109                  protocol_identifier,
 110                  protocol_identifier==0xe1?"DEC Spanning Tree Protocol":
 111                  "Unknown protocol, the dissection may be wrong");
 112
 113             proto_tree_add_text(bpdu_tree, tvb, BPDU_TYPE,1, "BPDU Type: %u (%s)", bpdu_type,
 114                 (bpdu_type==25?"Hello Packet":(bpdu_type==2?"Topology change notice":"Unknown")));
 115
 116             proto_tree_add_text(bpdu_tree, tvb, BPDU_VERSION,1, "BPDU Version: %u (%s)",
 117                 protocol_version,protocol_version==1?"DEC STP Version 1":"Unknown Version");
 118
 119             proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS,1, "Flags: 0x%02x",flags);
 120
 121             if (flags & 0x80)
 122                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "      1... ....  Use short timers");
 123             if (flags & 0x02)
 124                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "      .... ..1.  Topology Change Acknowledgment");
 125             if (flags & 0x01)
 126                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "      .... ...1  Topology Change");
 127
 128             proto_tree_add_text(bpdu_tree, tvb, BPDU_ROOT_PRI,2, "Root priority: %u",
 129                 tvb_get_ntohs(tvb,BPDU_ROOT_PRI));
 130             proto_tree_add_text(bpdu_tree, tvb, BPDU_ROOT_MAC,6, "Root MAC: %s",
 131                 ether_to_str(tvb_get_ptr(tvb,BPDU_ROOT_MAC,6)));
 132             proto_tree_add_text(bpdu_tree, tvb, BPDU_ROOT_PATH_COST,2, "Root path cost: %u",
 133                 tvb_get_ntohs(tvb,BPDU_ROOT_PATH_COST));
 134             proto_tree_add_text(bpdu_tree, tvb, BPDU_BRIDGE_PRI,2, "Root priority: %u",
 135                 tvb_get_ntohs(tvb,BPDU_BRIDGE_PRI));
 136             proto_tree_add_text(bpdu_tree, tvb, BPDU_BRIDGE_MAC,6, "Root MAC: %s",
 137                 ether_to_str(tvb_get_ptr(tvb,BPDU_BRIDGE_MAC,6)));
 138             proto_tree_add_text(bpdu_tree, tvb, BPDU_PORT_IDENTIFIER,1, "Port identifier: %u",
 139                 tvb_get_guint8(tvb,BPDU_PORT_IDENTIFIER));
 140             proto_tree_add_text(bpdu_tree, tvb, BPDU_MESSAGE_AGE,1, "Age: %u",
 141                 tvb_get_guint8(tvb,BPDU_MESSAGE_AGE));
 142             proto_tree_add_text(bpdu_tree, tvb, BPDU_HELLO_TIME,1, "Hello time: %u",
 143                 tvb_get_guint8(tvb,BPDU_HELLO_TIME));
 144             proto_tree_add_text(bpdu_tree, tvb, BPDU_MAX_AGE,1, "Max Age: %u",
 145                 tvb_get_guint8(tvb,BPDU_MAX_AGE));
 146             proto_tree_add_text(bpdu_tree, tvb, BPDU_FORWARD_DELAY,1, "Forward Delay: %u",
 147                 tvb_get_guint8(tvb,BPDU_FORWARD_DELAY));
 148
 149       }
 150 }
 151
 152 void
 153 proto_register_dec_bpdu(void)
 154 {
 155   static gint *ett[] = {
 156     &ett_dec_bpdu,
 157   };
 158
 159   proto_dec_bpdu = proto_register_protocol("DEC Spanning Tree Protocol",
 160                                            "DEC_STP", "dec_stp");
 161   proto_register_subtree_array(ett, array_length(ett));
 162 }
 163
 164 void
 165 proto_reg_handoff_dec_bpdu(void)
 166 {
 167   dissector_handle_t dec_bpdu_handle;
 168
 169   dec_bpdu_handle = create_dissector_handle(dissect_dec_bpdu,
 170                                             proto_dec_bpdu);
 171   dissector_add("ethertype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 172   dissector_add("chdlctype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
 173   dissector_add("ppp.protocol", PPP_DEC_LB, dec_bpdu_handle);
 174 }