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wireshark/packet-bpdu.c

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/* packet-bpdu.c
* Routines for BPDU (Spanning Tree Protocol) disassembly
*
* $Id: packet-bpdu.c,v 1.31 2002/01/21 07:36:32 guy Exp $
*
* Copyright 1999 Christophe Tronche <ch.tronche@computer.org>
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* 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 <epan/packet.h>
#include "llcsaps.h"
#include "ppptypes.h"
#include <epan/resolv.h>
/* 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;
static int hf_bpdu_proto_id = -1;
static int hf_bpdu_version_id = -1;
static int hf_bpdu_type = -1;
static int hf_bpdu_flags = -1;
static int hf_bpdu_root_mac = -1;
static int hf_bpdu_root_cost = -1;
static int hf_bpdu_bridge_mac = -1;
static int hf_bpdu_port_id = -1;
static int hf_bpdu_msg_age = -1;
static int hf_bpdu_max_age = -1;
static int hf_bpdu_hello_time = -1;
static int hf_bpdu_forward_delay = -1;
static gint ett_bpdu = -1;
static dissector_handle_t gvrp_handle;
static dissector_handle_t gmrp_handle;
static dissector_handle_t data_handle;
static void
dissect_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
guint16 protocol_identifier;
guint8 protocol_version_identifier;
guint8 bpdu_type;
guint8 flags;
guint16 root_identifier_bridge_priority;
const guint8 *root_identifier_mac;
gchar *root_identifier_mac_str;
guint32 root_path_cost;
guint16 bridge_identifier_bridge_priority;
const guint8 *bridge_identifier_mac;
gchar *bridge_identifier_mac_str;
guint16 port_identifier;
double message_age;
double max_age;
double hello_time;
double forward_delay;
proto_tree *bpdu_tree;
proto_item *ti;
/* GARP application frames require special interpretation of the
destination address field; otherwise, they will be mistaken as
BPDU frames.
Fortunately, they can be recognized by checking the first 6 octets
of the destination address, which are in the range from
01-80-C2-00-00-20 to 01-80-C2-00-00-2F.
Yes - we *do* need to check the destination address type;
on Linux cooked captures, there *is* no destination address,
so it's AT_NONE. */
if (pinfo->dl_dst.type == AT_ETHER &&
pinfo->dl_dst.data[0] == 0x01 && pinfo->dl_dst.data[1] == 0x80 &&
pinfo->dl_dst.data[2] == 0xC2 && pinfo->dl_dst.data[3] == 0x00 &&
pinfo->dl_dst.data[4] == 0x00 && ((pinfo->dl_dst.data[5] & 0x20) == 0x20)) {
protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
switch (pinfo->dl_dst.data[5]) {
case 0x20:
/* for GMRP */
call_dissector(gmrp_handle, tvb, pinfo, tree);
return;
case 0x21:
/* for GVRP */
call_dissector(gvrp_handle, tvb, pinfo, tree);
return;
}
pinfo->current_proto = "GARP";
if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
col_set_str(pinfo->cinfo, COL_PROTOCOL, "GARP");
/* Generic Attribute Registration Protocol */
}
if (check_col(pinfo->cinfo, COL_INFO)) {
col_add_fstr(pinfo->cinfo, COL_INFO,
"Unknown GARP application (0x%02X)",
pinfo->dl_dst.data[5]);
}
return;
}
if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
col_set_str(pinfo->cinfo, COL_PROTOCOL, "STP"); /* Spanning Tree Protocol */
}
if (check_col(pinfo->cinfo, COL_INFO)) {
col_clear(pinfo->cinfo, COL_INFO);
}
bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
if (bpdu_type == 0) {
flags = tvb_get_guint8(tvb, BPDU_FLAGS);
root_identifier_bridge_priority = tvb_get_ntohs(tvb,
BPDU_ROOT_IDENTIFIER);
root_identifier_mac = tvb_get_ptr(tvb, BPDU_ROOT_IDENTIFIER + 2, 6);
root_identifier_mac_str = ether_to_str(root_identifier_mac);
root_path_cost = tvb_get_ntohl(tvb, BPDU_ROOT_PATH_COST);
port_identifier = tvb_get_ntohs(tvb, BPDU_PORT_IDENTIFIER);
} else {
/* Squelch GCC complaints. */
flags = 0;
root_identifier_bridge_priority = 0;
root_identifier_mac = NULL;
root_identifier_mac_str = NULL;
root_path_cost = 0;
port_identifier = 0;
}
if (check_col(pinfo->cinfo, COL_INFO)) {
if (bpdu_type == 0)
col_add_fstr(pinfo->cinfo, COL_INFO, "Conf. %sRoot = %d/%s Cost = %d Port = 0x%04x",
flags & 0x1 ? "TC + " : "",
root_identifier_bridge_priority, root_identifier_mac_str, root_path_cost,
port_identifier);
else if (bpdu_type == 0x80)
col_add_fstr(pinfo->cinfo, COL_INFO, "Topology Change Notification");
}
if (tree) {
ti = proto_tree_add_protocol_format(tree, proto_bpdu, tvb, 0, 35,
"Spanning Tree Protocol");
bpdu_tree = proto_item_add_subtree(ti, ett_bpdu);
protocol_identifier = tvb_get_ntohs(tvb, BPDU_IDENTIFIER);
proto_tree_add_uint_format(bpdu_tree, hf_bpdu_proto_id, tvb,
BPDU_IDENTIFIER, 2,
protocol_identifier,
"Protocol Identifier: 0x%04x (%s)",
protocol_identifier,
protocol_identifier == 0 ?
"Spanning Tree" : "Unknown Protocol");
protocol_version_identifier = tvb_get_guint8(tvb, BPDU_VERSION_IDENTIFIER);
proto_tree_add_uint(bpdu_tree, hf_bpdu_version_id, tvb,
BPDU_VERSION_IDENTIFIER, 1,
protocol_version_identifier);
if (protocol_version_identifier != 0)
proto_tree_add_text(bpdu_tree, tvb, BPDU_VERSION_IDENTIFIER, 1,
" (Warning: this version of Ethereal only knows about version = 0)");
proto_tree_add_uint_format(bpdu_tree, hf_bpdu_type, tvb,
BPDU_TYPE, 1,
bpdu_type,
"BPDU Type: 0x%02x (%s)",
bpdu_type,
bpdu_type == 0 ? "Configuration" :
bpdu_type == 0x80 ? "Topology Change Notification" : "Unknown");
if (bpdu_type != 0) {
call_dissector(data_handle,tvb_new_subset(tvb, BPDU_TYPE + 1,-1,tvb_reported_length_remaining(tvb,BPDU_TYPE + 1)), pinfo, tree);
return;
}
bridge_identifier_bridge_priority = tvb_get_ntohs(tvb, BPDU_BRIDGE_IDENTIFIER);
bridge_identifier_mac = tvb_get_ptr(tvb, BPDU_BRIDGE_IDENTIFIER + 2, 6);
bridge_identifier_mac_str = ether_to_str(bridge_identifier_mac);
message_age = tvb_get_ntohs(tvb, BPDU_MESSAGE_AGE) / 256.0;
max_age = tvb_get_ntohs(tvb, BPDU_MAX_AGE) / 256.0;
hello_time = tvb_get_ntohs(tvb, BPDU_HELLO_TIME) / 256.0;
forward_delay = tvb_get_ntohs(tvb, BPDU_FORWARD_DELAY) / 256.0;
proto_tree_add_uint(bpdu_tree, hf_bpdu_flags, tvb,
BPDU_FLAGS, 1, flags);
if (flags & 0x80)
proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, " 1... .... Topology Change Acknowledgment");
if (flags & 0x01)
proto_tree_add_text(bpdu_tree, tvb, BPDU_FLAGS, 1, " .... ...1 Topology Change");
proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_root_mac, tvb,
BPDU_ROOT_IDENTIFIER + 2, 6,
root_identifier_mac);
proto_tree_add_text(bpdu_tree, tvb,
BPDU_ROOT_IDENTIFIER, 8,
"Root Identifier: %d / %s",
root_identifier_bridge_priority,
root_identifier_mac_str);
proto_tree_add_uint(bpdu_tree, hf_bpdu_root_cost, tvb,
BPDU_ROOT_PATH_COST, 4,
root_path_cost);
proto_tree_add_text(bpdu_tree, tvb,
BPDU_BRIDGE_IDENTIFIER, 8,
"Bridge Identifier: %d / %s",
bridge_identifier_bridge_priority,
bridge_identifier_mac_str);
proto_tree_add_ether_hidden(bpdu_tree, hf_bpdu_bridge_mac, tvb,
BPDU_BRIDGE_IDENTIFIER + 2, 6,
bridge_identifier_mac);
proto_tree_add_uint(bpdu_tree, hf_bpdu_port_id, tvb,
BPDU_PORT_IDENTIFIER, 2,
port_identifier);
proto_tree_add_double(bpdu_tree, hf_bpdu_msg_age, tvb,
BPDU_MESSAGE_AGE, 2,
message_age);
proto_tree_add_double(bpdu_tree, hf_bpdu_max_age, tvb,
BPDU_MAX_AGE, 2,
max_age);
proto_tree_add_double(bpdu_tree, hf_bpdu_hello_time, tvb,
BPDU_HELLO_TIME, 2,
hello_time);
proto_tree_add_double(bpdu_tree, hf_bpdu_forward_delay, tvb,
BPDU_FORWARD_DELAY, 2,
forward_delay);
}
}
void
proto_register_bpdu(void)
{
static hf_register_info hf[] = {
{ &hf_bpdu_proto_id,
{ "Protocol Identifier", "stp.protocol",
FT_UINT16, BASE_HEX, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_version_id,
{ "Protocol Version Identifier", "stp.version",
FT_UINT8, BASE_DEC, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_type,
{ "BPDU type", "stp.type",
FT_UINT8, BASE_HEX, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_flags,
{ "BPDU flags", "stp.flags",
FT_UINT8, BASE_HEX, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_root_mac,
{ "Root Identifier", "stp.root.hw",
FT_ETHER, BASE_NONE, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_root_cost,
{ "Root Path Cost", "stp.root.cost",
FT_UINT32, BASE_DEC, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_bridge_mac,
{ "Bridge Identifier", "stp.bridge.hw",
FT_ETHER, BASE_NONE, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_port_id,
{ "Port identifier", "stp.port",
FT_UINT16, BASE_HEX, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_msg_age,
{ "Message Age", "stp.msg_age",
FT_DOUBLE, BASE_NONE, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_max_age,
{ "Max Age", "stp.max_age",
FT_DOUBLE, BASE_NONE, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_hello_time,
{ "Hello Time", "stp.hello",
FT_DOUBLE, BASE_NONE, NULL, 0x0,
"", HFILL }},
{ &hf_bpdu_forward_delay,
{ "Forward Delay", "stp.forward",
FT_DOUBLE, BASE_NONE, NULL, 0x0,
"", HFILL }},
};
static gint *ett[] = {
&ett_bpdu,
};
proto_bpdu = proto_register_protocol("Spanning Tree Protocol", "STP", "stp");
proto_register_field_array(proto_bpdu, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
register_dissector("bpdu", dissect_bpdu, proto_bpdu);
}
void
proto_reg_handoff_bpdu(void)
{
dissector_handle_t bpdu_handle;
/*
* Get handle for the GVRP dissector.
*/
gvrp_handle = find_dissector("gvrp");
/*
* Get handle for the GMRP dissector.
*/
gmrp_handle = find_dissector("gmrp");
data_handle = find_dissector("data");
bpdu_handle = find_dissector("bpdu");
dissector_add("llc.dsap", SAP_BPDU, bpdu_handle);
dissector_add("ppp.protocol", PPP_BPDU, bpdu_handle);
}
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