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/* packet-bpdu.c
* Routines for BPDU (Spanning Tree Protocol) disassembly
*
* $Id: packet-bpdu.c,v 1.2 1999/10/08 21:20:23 guy Exp $
*
* Copyright 1999 Christophe Tronche <ch.tronche@computer.org>
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
* Copyright 1998 Gerald Combs
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#include <stdio.h>
#include <string.h>
#include <glib.h>
#include "packet.h"
#include "resolv.h"
#include "util.h"
/* #ifndef __PACKET_IP_H__ */
/* #include "packet-ip.h" */
/* #endif */
/* Offsets of fields within a BPDU */
#define BPDU_IDENTIFIER 0
#define BPDU_VERSION_IDENTIFIER 2
#define BPDU_TYPE 3
#define BPDU_FLAGS 4
#define BPDU_ROOT_IDENTIFIER 5
#define BPDU_ROOT_PATH_COST 13
#define BPDU_BRIDGE_IDENTIFIER 17
#define BPDU_PORT_IDENTIFIER 25
#define BPDU_MESSAGE_AGE 27
#define BPDU_MAX_AGE 29
#define BPDU_HELLO_TIME 31
#define BPDU_FORWARD_DELAY 33
static int proto_bpdu = -1;
void dissect_bpdu(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
guint16 protocol_identifier;
guint8 protocol_version_identifier;
guint8 bpdu_type;
guint8 flags;
guint16 root_identifier_bridge_priority;
gchar *root_identifier_mac;
guint32 root_path_cost;
guint16 bridge_identifier_bridge_priority;
gchar *bridge_identifier_mac;
guint16 port_identifier;
double message_age;
double max_age;
double hello_time;
double forward_delay;
proto_tree *bpdu_tree;
proto_item *ti;
const u_char *bpdu;
bpdu = pd + offset;
bpdu_type = (guint8) bpdu[BPDU_TYPE];
flags = (guint8) bpdu[BPDU_FLAGS];
root_identifier_bridge_priority = pntohs(bpdu + BPDU_ROOT_IDENTIFIER);
root_identifier_mac = ether_to_str(bpdu + BPDU_ROOT_IDENTIFIER + 2);
root_path_cost = pntohl(bpdu + BPDU_ROOT_PATH_COST);
port_identifier = pntohs(bpdu + BPDU_PORT_IDENTIFIER);
if (check_col(fd, COL_PROTOCOL)) {
col_add_str(fd, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
}
if (check_col(fd, COL_INFO)) {
if (bpdu_type == 0)
col_add_fstr(fd, COL_INFO, "Conf. %sRoot = %d/%s Cost = %d Port = 0x%04x",
flags & 0x1 ? "TC + " : "",
root_identifier_bridge_priority, root_identifier_mac, root_path_cost,
port_identifier);
else if (bpdu_type == 0x80)
col_add_fstr(fd, COL_INFO, "Topology Change Notification");
}
if (tree) {
protocol_identifier = pntohs(bpdu + BPDU_IDENTIFIER);
protocol_version_identifier = (guint8) bpdu[BPDU_VERSION_IDENTIFIER];
ti = proto_tree_add_item_format(tree, proto_bpdu, offset, 35, NULL, "Spanning Tree Protocol");
bpdu_tree = proto_item_add_subtree(ti, ETT_BPDU);
proto_tree_add_text(bpdu_tree, offset + BPDU_IDENTIFIER, 2, "Protocol Identifier: 0x%04x (%s)",
protocol_identifier,
protocol_identifier == 0 ? "Spanning Tree" : "Unknown Protocol");
proto_tree_add_text(bpdu_tree, offset + BPDU_VERSION_IDENTIFIER, 1, "Protocol Version Identifier: %d", protocol_version_identifier);
if (protocol_version_identifier != 0)
proto_tree_add_text(bpdu_tree, offset + BPDU_VERSION_IDENTIFIER, 1, " (Warning: this version of packet-bpdu only knows about version = 0)");
proto_tree_add_text(bpdu_tree, offset + BPDU_TYPE, 1, "BPDU Type: 0x%02x (%s)",
bpdu_type,
bpdu_type == 0 ? "Configuration" :
bpdu_type == 0x80 ? "Topology Change Notification" : "Unknown");
if (bpdu_type != 0) return;
bridge_identifier_bridge_priority = pntohs(bpdu + BPDU_BRIDGE_IDENTIFIER);
bridge_identifier_mac = ether_to_str(bpdu + BPDU_BRIDGE_IDENTIFIER + 2);
message_age = pntohs(bpdu + BPDU_MESSAGE_AGE) / 256.0;
max_age = pntohs(bpdu + BPDU_MAX_AGE) / 256.0;
hello_time = pntohs(bpdu + BPDU_HELLO_TIME) / 256.0;
forward_delay = pntohs(bpdu + BPDU_FORWARD_DELAY) / 256.0;
proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, "Flags: 0x%02x", flags);
if (flags & 0x80)
proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, " 1... .... Topology Change Acknowledgment");
if (flags & 0x01)
proto_tree_add_text(bpdu_tree, offset + BPDU_FLAGS, 1, " .... ...1 Topology Change");
proto_tree_add_text(bpdu_tree, offset + BPDU_ROOT_IDENTIFIER, 8, "Root Identifier: %d / %s", root_identifier_bridge_priority, root_identifier_mac);
proto_tree_add_text(bpdu_tree, offset + BPDU_ROOT_PATH_COST, 4, "Root Path Cost: %d", root_path_cost);
proto_tree_add_text(bpdu_tree, offset + BPDU_BRIDGE_IDENTIFIER, 8, "Bridge Identifier: %d / %s",
bridge_identifier_bridge_priority,
bridge_identifier_mac);
proto_tree_add_text(bpdu_tree, offset + BPDU_PORT_IDENTIFIER, 2, "Port identifier: 0x%04x", port_identifier);
proto_tree_add_text(bpdu_tree, offset + BPDU_MESSAGE_AGE, 2, "Message Age: %f", message_age);
proto_tree_add_text(bpdu_tree, offset + BPDU_MAX_AGE, 2, "Max Age: %f", max_age);
proto_tree_add_text(bpdu_tree, offset + BPDU_HELLO_TIME, 2, "Hello Time: %f", hello_time);
proto_tree_add_text(bpdu_tree, offset + BPDU_FORWARD_DELAY, 2, "Forward Delay: %f", forward_delay);
}
}
void
proto_register_bpdu(void)
{
proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "stp");
}
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