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/* packet-dec-bpdu.c
* Routines for DEC BPDU (DEC Spanning Tree Protocol) disassembly
*
* Copyright 2001 Paul Ionescu <paul@acorp.ro>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/etypes.h>
#include <epan/ppptypes.h>
/* Offsets of fields within a BPDU */
#define BPDU_DEC_CODE 0
#define BPDU_TYPE 1
#define BPDU_VERSION 2
#define BPDU_FLAGS 3
#define BPDU_ROOT_PRI 4
#define BPDU_ROOT_MAC 6
#define BPDU_ROOT_PATH_COST 12
#define BPDU_BRIDGE_PRI 14
#define BPDU_BRIDGE_MAC 16
#define BPDU_PORT_IDENTIFIER 22
#define BPDU_MESSAGE_AGE 23
#define BPDU_HELLO_TIME 24
#define BPDU_MAX_AGE 25
#define BPDU_FORWARD_DELAY 26
#define DEC_BPDU_SIZE 27
/* Flag bits */
#define BPDU_FLAGS_SHORT_TIMERS 0x80
#define BPDU_FLAGS_TCACK 0x02
#define BPDU_FLAGS_TC 0x01
void proto_register_dec_bpdu(void);
void proto_reg_handoff_dec_bpdu(void);
static dissector_handle_t dec_bpdu_handle;
static int proto_dec_bpdu = -1;
static int hf_dec_bpdu_proto_id = -1;
static int hf_dec_bpdu_type = -1;
static int hf_dec_bpdu_version_id = -1;
static int hf_dec_bpdu_flags = -1;
static int hf_dec_bpdu_flags_short_timers = -1;
static int hf_dec_bpdu_flags_tcack = -1;
static int hf_dec_bpdu_flags_tc = -1;
static int hf_dec_bpdu_root_pri = -1;
static int hf_dec_bpdu_root_mac = -1;
static int hf_dec_bpdu_root_cost = -1;
static int hf_dec_bpdu_bridge_pri = -1;
static int hf_dec_bpdu_bridge_mac = -1;
static int hf_dec_bpdu_port_id = -1;
static int hf_dec_bpdu_msg_age = -1;
static int hf_dec_bpdu_hello_time = -1;
static int hf_dec_bpdu_max_age = -1;
static int hf_dec_bpdu_forward_delay = -1;
static gint ett_dec_bpdu = -1;
static gint ett_dec_bpdu_flags = -1;
static const value_string protocol_id_vals[] = {
{ 0xe1, "DEC Spanning Tree Protocol" },
{ 0, NULL }
};
#define BPDU_TYPE_TOPOLOGY_CHANGE 2
#define BPDU_TYPE_HELLO 25
static const value_string bpdu_type_vals[] = {
{ BPDU_TYPE_TOPOLOGY_CHANGE, "Topology Change Notification" },
{ BPDU_TYPE_HELLO, "Hello Packet" },
{ 0, NULL }
};
static int
dissect_dec_bpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
guint8 bpdu_type;
proto_tree *bpdu_tree;
proto_item *ti;
static int * const bpdu_flags[] = {
&hf_dec_bpdu_flags_short_timers,
&hf_dec_bpdu_flags_tcack,
&hf_dec_bpdu_flags_tc,
NULL
};
col_set_str(pinfo->cinfo, COL_PROTOCOL, "DEC_STP");
col_clear(pinfo->cinfo, COL_INFO);
bpdu_type = tvb_get_guint8(tvb, BPDU_TYPE);
col_add_str(pinfo->cinfo, COL_INFO,
val_to_str(bpdu_type, bpdu_type_vals,
"Unknown BPDU type (%u)"));
set_actual_length(tvb, DEC_BPDU_SIZE);
if (tree) {
ti = proto_tree_add_item(tree, proto_dec_bpdu, tvb, 0, DEC_BPDU_SIZE,
ENC_NA);
bpdu_tree = proto_item_add_subtree(ti, ett_dec_bpdu);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_proto_id, tvb,
BPDU_DEC_CODE, 1, ENC_BIG_ENDIAN);
proto_tree_add_uint(bpdu_tree, hf_dec_bpdu_type, tvb,
BPDU_TYPE, 1, bpdu_type);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_version_id, tvb,
BPDU_VERSION, 1, ENC_BIG_ENDIAN);
proto_tree_add_bitmask_with_flags(bpdu_tree, tvb, BPDU_FLAGS, hf_dec_bpdu_flags, ett_dec_bpdu_flags, bpdu_flags, ENC_NA, BMT_NO_FALSE|BMT_NO_TFS);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_pri, tvb,
BPDU_ROOT_PRI, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_mac, tvb,
BPDU_ROOT_MAC, 6, ENC_NA);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_root_cost, tvb,
BPDU_ROOT_PATH_COST, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_pri, tvb,
BPDU_BRIDGE_PRI, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_bridge_mac, tvb,
BPDU_BRIDGE_MAC, 6, ENC_NA);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_port_id, tvb,
BPDU_PORT_IDENTIFIER, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_msg_age, tvb,
BPDU_MESSAGE_AGE, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_hello_time, tvb,
BPDU_HELLO_TIME, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_max_age, tvb,
BPDU_MAX_AGE, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(bpdu_tree, hf_dec_bpdu_forward_delay, tvb,
BPDU_FORWARD_DELAY, 1, ENC_BIG_ENDIAN);
}
return tvb_captured_length(tvb);
}
void
proto_register_dec_bpdu(void)
{
static hf_register_info hf[] = {
{ &hf_dec_bpdu_proto_id,
{ "Protocol Identifier", "dec_stp.protocol",
FT_UINT8, BASE_HEX, VALS(protocol_id_vals), 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_type,
{ "BPDU Type", "dec_stp.type",
FT_UINT8, BASE_DEC, VALS(bpdu_type_vals), 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_version_id,
{ "BPDU Version", "dec_stp.version",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_flags,
{ "BPDU flags", "dec_stp.flags",
FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_flags_short_timers,
{ "Use short timers", "dec_stp.flags.short_timers",
FT_BOOLEAN, 8, TFS(&tfs_yes_no), BPDU_FLAGS_SHORT_TIMERS,
NULL, HFILL }},
{ &hf_dec_bpdu_flags_tcack,
{ "Topology Change Acknowledgment", "dec_stp.flags.tcack",
FT_BOOLEAN, 8, TFS(&tfs_yes_no), BPDU_FLAGS_TCACK,
NULL, HFILL }},
{ &hf_dec_bpdu_flags_tc,
{ "Topology Change", "dec_stp.flags.tc",
FT_BOOLEAN, 8, TFS(&tfs_yes_no), BPDU_FLAGS_TC,
NULL, HFILL }},
{ &hf_dec_bpdu_root_pri,
{ "Root Priority", "dec_stp.root.pri",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_root_mac,
{ "Root MAC", "dec_stp.root.mac",
FT_ETHER, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_root_cost,
{ "Root Path Cost", "dec_stp.root.cost",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_bridge_pri,
{ "Bridge Priority", "dec_stp.bridge.pri",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_bridge_mac,
{ "Bridge MAC", "dec_stp.bridge.mac",
FT_ETHER, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_port_id,
{ "Port identifier", "dec_stp.port",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_msg_age,
{ "Message Age", "dec_stp.msg_age",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_hello_time,
{ "Hello Time", "dec_stp.hello",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_max_age,
{ "Max Age", "dec_stp.max_age",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_dec_bpdu_forward_delay,
{ "Forward Delay", "dec_stp.forward",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
};
static gint *ett[] = {
&ett_dec_bpdu,
&ett_dec_bpdu_flags,
};
proto_dec_bpdu = proto_register_protocol("DEC Spanning Tree Protocol",
"DEC_STP", "dec_stp");
proto_register_field_array(proto_dec_bpdu, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
dec_bpdu_handle = register_dissector("dec_stp", dissect_dec_bpdu,
proto_dec_bpdu);
}
void
proto_reg_handoff_dec_bpdu(void)
{
dissector_add_uint("ethertype", ETHERTYPE_DEC_LB, dec_bpdu_handle);
dissector_add_uint("chdlc.protocol", ETHERTYPE_DEC_LB, dec_bpdu_handle);
dissector_add_uint("ppp.protocol", PPP_DEC_LB, dec_bpdu_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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