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 1.3 2001/01/07 00:23:03 guy Exp $
   5  *
   6  * Copyright 2001 Paul Ionescu <paul@acorp.ro>
   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 #include "etypes.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       CHECK_DISPLAY_AS_DATA(proto_dec_bpdu, tvb, pinfo, tree);
  81
  82       pinfo->current_proto = "DEC_STP";
  83
  84       if (check_col(pinfo->fd, COL_PROTOCOL)) {
  85             col_set_str(pinfo->fd, COL_PROTOCOL, "DEC_STP");
  86       }
  87
  88       bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
  89       flags=tvb_get_guint8(tvb,BPDU_FLAGS);
  90
  91       if (check_col(pinfo->fd, COL_INFO)) {
  92             if (bpdu_type == 25)
  93                   col_add_fstr(pinfo->fd, COL_INFO, "Hello Packet");
  94             else if (bpdu_type == 0x02)
  95                   col_add_fstr(pinfo->fd, COL_INFO, "Topology Change Notification");
  96       }
  97
  98       tvb_set_reported_length(tvb, DEC_BPDU_SIZE);
  99
 100       if (tree) {
 101             protocol_identifier = tvb_get_guint8(tvb, BPDU_DEC_CODE);
 102
 103             protocol_version = tvb_get_guint8(tvb, BPDU_VERSION);
 104
 105             ti = proto_tree_add_protocol_format(tree, proto_dec_bpdu, tvb, 0, DEC_BPDU_SIZE,
 106                                 "DEC Spanning Tree Protocol");
 107             bpdu_tree = proto_item_add_subtree(ti, ett_dec_bpdu);
 108
 109             proto_tree_add_text(bpdu_tree, tvb, BPDU_DEC_CODE, 1, "Protocol ID: 0x%02x (%s)",
 110                  protocol_identifier,
 111                  protocol_identifier==0xe1?"DEC Spanning Tree Protocol":
 112                  "Unknown protocol, the dissection may be wrong");
 113
 114             proto_tree_add_text(bpdu_tree, tvb, BPDU_TYPE,1, "BPDU Type: %u (%s)", bpdu_type,
 115                 (bpdu_type==25?"Hello Packet":(bpdu_type==2?"Topology change notice":"Unknown")));
 116
 117             proto_tree_add_text(bpdu_tree, tvb, BPDU_VERSION,1, "BPDU Version: %u (%s)",
 118                 protocol_version,protocol_version==1?"DEC STP Version 1":"Unknown Version");
 119
 120             proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS,1, "Flags: 0x%02x",flags);
 121
 122             if (flags & 0x80)
 123                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "      1... ....  Use short timers");
 124             if (flags & 0x02)
 125                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "      .... ..1.  Topology Change Acknowledgment");
 126             if (flags & 0x01)
 127                   proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, "      .... ...1  Topology Change");
 128
 129             proto_tree_add_text(bpdu_tree, tvb, BPDU_ROOT_PRI,2, "Root priority: %u",
 130                 tvb_get_ntohs(tvb,BPDU_ROOT_PRI));
 131             proto_tree_add_text(bpdu_tree, tvb, BPDU_ROOT_MAC,6, "Root MAC: %s",
 132                 ether_to_str(tvb_get_ptr(tvb,BPDU_ROOT_MAC,6)));
 133             proto_tree_add_text(bpdu_tree, tvb, BPDU_ROOT_PATH_COST,2, "Root path cost: %u",
 134                 tvb_get_ntohs(tvb,BPDU_ROOT_PATH_COST));
 135             proto_tree_add_text(bpdu_tree, tvb, BPDU_BRIDGE_PRI,2, "Root priority: %u",
 136                 tvb_get_ntohs(tvb,BPDU_BRIDGE_PRI));
 137             proto_tree_add_text(bpdu_tree, tvb, BPDU_BRIDGE_MAC,6, "Root MAC: %s",
 138                 ether_to_str(tvb_get_ptr(tvb,BPDU_BRIDGE_MAC,6)));
 139             proto_tree_add_text(bpdu_tree, tvb, BPDU_PORT_IDENTIFIER,1, "Port identifier: %u",
 140                 tvb_get_guint8(tvb,BPDU_PORT_IDENTIFIER));
 141             proto_tree_add_text(bpdu_tree, tvb, BPDU_MESSAGE_AGE,1, "Age: %u",
 142                 tvb_get_guint8(tvb,BPDU_MESSAGE_AGE));
 143             proto_tree_add_text(bpdu_tree, tvb, BPDU_HELLO_TIME,1, "Hello time: %u",
 144                 tvb_get_guint8(tvb,BPDU_HELLO_TIME));
 145             proto_tree_add_text(bpdu_tree, tvb, BPDU_MAX_AGE,1, "Max Age: %u",
 146                 tvb_get_guint8(tvb,BPDU_MAX_AGE));
 147             proto_tree_add_text(bpdu_tree, tvb, BPDU_FORWARD_DELAY,1, "Forward Delay: %u",
 148                 tvb_get_guint8(tvb,BPDU_FORWARD_DELAY));
 149
 150       }
 151 }
 152
 153 void
 154 proto_register_dec_bpdu(void)
 155 {
 156   static gint *ett[] = {
 157     &ett_dec_bpdu,
 158   };
 159
 160   proto_dec_bpdu = proto_register_protocol("DEC Spanning Tree Protocol", "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_add("ethertype", ETHERTYPE_DEC_LB, dissect_dec_bpdu);
 168 }