packet-bpdu.c

   1 /* packet-bpdu.c
   2  * Routines for BPDU (Spanning Tree Protocol) disassembly
   3  *
   4  * $Id: packet-bpdu.c,v 1.1 1999/10/08 20:50:38 guy Exp $
   5  *
   6  * Copyright 1999 Christophe Tronche <ch.tronche@computer.org>
   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 "util.h"
  46
  47 /*  #ifndef __PACKET_IP_H__ */
  48 /*  #include "packet-ip.h" */
  49 /*  #endif */
  50
  51 /* Offsets of fields within a BPDU */
  52
  53 #define BPDU_IDENTIFIER          0
  54 #define BPDU_VERSION_IDENTIFIER  2
  55 #define BPDU_TYPE                3
  56 #define BPDU_FLAGS               4
  57 #define BPDU_ROOT_IDENTIFIER     5
  58 #define BPDU_ROOT_PATH_COST     13
  59 #define BPDU_BRIDGE_IDENTIFIER  17
  60 #define BPDU_PORT_IDENTIFIER    25
  61 #define BPDU_MESSAGE_AGE        27
  62 #define BPDU_MAX_AGE            29
  63 #define BPDU_HELLO_TIME         31
  64 #define BPDU_FORWARD_DELAY      33
  65
  66 static int proto_bpdu = -1;
  67
  68 void dissect_bpdu(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
  69       guint16 protocol_identifier;
  70       guint8  protocol_version_identifier;
  71       guint8  bpdu_type;
  72       guint8  flags;
  73       guint16 root_identifier_bridge_priority;
  74       gchar   *root_identifier_mac;
  75       guint32 root_path_cost;
  76       guint16 bridge_identifier_bridge_priority;
  77       gchar   *bridge_identifier_mac;
  78       guint16 port_identifier;
  79       double message_age;
  80       double max_age;
  81       double hello_time;
  82       double forward_delay;
  83
  84       proto_tree *bpdu_tree;
  85       proto_item *ti;
  86       const u_char *bpdu;
  87
  88       bpdu = pd + offset;
  89       bpdu_type = (guint8) bpdu[BPDU_TYPE];
  90       flags = (guint8) bpdu[BPDU_FLAGS];
  91       root_identifier_bridge_priority = pntohs(bpdu + BPDU_ROOT_IDENTIFIER);
  92       root_identifier_mac = ether_to_str(bpdu + BPDU_ROOT_IDENTIFIER + 2);
  93       root_path_cost = pntohl(bpdu + BPDU_ROOT_PATH_COST);
  94       port_identifier = pntohs(bpdu + BPDU_PORT_IDENTIFIER);
  95
  96       if (check_col(fd, COL_PROTOCOL)) {
  97             col_add_str(fd, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
  98       }
  99
 100       if (check_col(fd, COL_INFO)) {
 101             if (bpdu_type == 0)
 102                   col_add_fstr(fd, COL_INFO, "Conf. %sRoot = %d/%s  Cost = %d  Port = 0x%04x",
 103                                flags & 0x1 ? "TC + " : "",
 104                                root_identifier_bridge_priority, root_identifier_mac, root_path_cost,
 105                                port_identifier);
 106             else if (bpdu_type == 0x80)
 107                   col_add_fstr(fd, COL_INFO, "Topology Change Notification");
 108       }
 109
 110       if (tree) {
 111             protocol_identifier = pntohs(bpdu + BPDU_IDENTIFIER);
 112             protocol_version_identifier = (guint8) bpdu[BPDU_VERSION_IDENTIFIER];
 113
 114             ti = proto_tree_add_item_format(tree, proto_bpdu, offset, 35, NULL, "Spanning Tree Protocol");
 115             bpdu_tree = proto_item_add_subtree(ti, ETT_BPDU);
 116             proto_tree_add_text(bpdu_tree, offset + BPDU_IDENTIFIER, 2, "Protocol Identifier: 0x%04x (%s)",
 117                                 protocol_identifier,
 118                                 protocol_identifier == 0 ? "Spanning Tree" : "Unknown Protocol");
 119
 120             proto_tree_add_text(bpdu_tree, offset + BPDU_VERSION_IDENTIFIER, 1, "Protocol Version Identifier: %d", protocol_version_identifier);
 121             if (protocol_version_identifier != 0)
 122                   proto_tree_add_text(bpdu_tree, offset + BPDU_VERSION_IDENTIFIER, 1, "   (Warning: this version of packet-bpdu only knows about version = 0)");
 123             proto_tree_add_text(bpdu_tree, offset + BPDU_TYPE, 1, "BPDU Type: 0x%02x (%s)",
 124                                 bpdu_type,
 125                                 bpdu_type == 0 ? "Configuration" :
 126                                 bpdu_type == 0x80 ? "Topology Change Notification" : "Unknown");
 127
 128             if (bpdu_type != 0) return;
 129
 130             bridge_identifier_bridge_priority = pntohs(bpdu + BPDU_BRIDGE_IDENTIFIER);
 131             bridge_identifier_mac = ether_to_str(bpdu + BPDU_BRIDGE_IDENTIFIER + 2);
 132             message_age = pntohs(bpdu + BPDU_MESSAGE_AGE) / 256.0;
 133             max_age = pntohs(bpdu + BPDU_MAX_AGE) / 256.0;
 134             hello_time = pntohs(bpdu + BPDU_HELLO_TIME) / 256.0;
 135             forward_delay = pntohs(bpdu + BPDU_FORWARD_DELAY) / 256.0;
 136
 137             proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "Flags: 0x%02x", flags);
 138             if (flags & 0x80)
 139                   proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "   1... ....  Topology Change Acknowledgment");
 140             if (flags & 0x01)
 141                   proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "   .... ...1  Topology Change");
 142
 143             proto_tree_add_text(bpdu_tree, offset + BPDU_ROOT_IDENTIFIER, 8, "Root Identifier: %d / %s", root_identifier_bridge_priority, root_identifier_mac);
 144             proto_tree_add_text(bpdu_tree, offset + BPDU_ROOT_PATH_COST, 4, "Root Path Cost: %d", root_path_cost);
 145             proto_tree_add_text(bpdu_tree, offset + BPDU_BRIDGE_IDENTIFIER, 8, "Bridge Identifier: %d / %s",
 146                                 bridge_identifier_bridge_priority,
 147                                 bridge_identifier_mac);
 148             proto_tree_add_text(bpdu_tree, offset + BPDU_PORT_IDENTIFIER, 2, "Port identifier: 0x%04x", port_identifier);
 149             proto_tree_add_text(bpdu_tree, offset + BPDU_MESSAGE_AGE, 2, "Message Age: %f", message_age);
 150             proto_tree_add_text(bpdu_tree, offset + BPDU_MAX_AGE, 2, "Max Age: %f", max_age);
 151             proto_tree_add_text(bpdu_tree, offset + BPDU_HELLO_TIME, 2, "Hello Time: %f", hello_time);
 152             proto_tree_add_text(bpdu_tree, offset + BPDU_FORWARD_DELAY, 2, "Forward Delay: %f", forward_delay);
 153       }
 154 }
 155
 156 void
 157 proto_register_bpdu(void)
 158 {
 159         proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "STP");
 160 }