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wireshark/packet-bssap.c

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/* packet-bssap.c
* Routines for Base Station Subsystem Application Part (BSSAP/BSAP) dissection
* Specifications from 3GPP2 (www.3gpp2.org) and 3GPP (www.3gpp.org)
* IOS 4.0.1 (BSAP)
* GSM 08.06 (BSSAP)
*
* Copyright 2003, Michael Lum <mlum [AT] telostech.com>
* In association with Telos Technology Inc.
*
* $Id: packet-bssap.c,v 1.9 2003/12/17 23:54:44 guy Exp $
*
* 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
#include <stdio.h>
#include <stdlib.h>
#include <gmodule.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#include <string.h>
#include "epan/packet.h"
#include "prefs.h"
#include "packet-bssap.h"
#define BSSAP 0
#define BSAP 1
#define BSSAP_OR_BSAP_DEFAULT BSSAP
#define PDU_TYPE_OFFSET 0
#define PDU_TYPE_LENGTH 1
/* Same as below but with names typed out */
static const value_string bssap_pdu_type_values[] = {
{ BSSAP_PDU_TYPE_BSSMAP, "BSS Management" },
{ BSSAP_PDU_TYPE_DTAP, "Direct Transfer" },
{ 0, NULL } };
static const value_string bsap_pdu_type_values[] = {
{ BSSAP_PDU_TYPE_BSSMAP, "BS Management" },
{ BSSAP_PDU_TYPE_DTAP, "Direct Transfer" },
{ 0, NULL } };
/* Same as above but in acronym for (for the Info column) */
static const value_string bssap_pdu_type_acro_values[] = {
{ BSSAP_PDU_TYPE_BSSMAP, "BSSMAP" },
{ BSSAP_PDU_TYPE_DTAP, "DTAP" },
{ 0, NULL } };
/* Same as above but in acronym for (for the Info column) */
static const value_string bsap_pdu_type_acro_values[] = {
{ BSSAP_PDU_TYPE_BSSMAP, "BSMAP" },
{ BSSAP_PDU_TYPE_DTAP, "DTAP" },
{ 0, NULL } };
#define PARAMETER_DLCI 0x00
#define PARAMETER_LENGTH 0x01
#define PARAMETER_DATA 0x02
#define DLCI_LENGTH 1
#define LENGTH_LENGTH 1
#define DATA_LENGTH 1
#define CC_MASK 0xc0
#define SPARE_MASK 0x38
#define SAPI_MASK 0x07
static const value_string bssap_cc_values[] = {
{ 0x00, "not further specified" },
{ 0x80, "FACCH or SDCCH" },
{ 0xc0, "SACCH" },
{ 0, NULL } };
static const value_string bsap_cc_values[] = {
{ 0x00, "default for TIA/EIA/IS-2000" },
{ 0, NULL } };
static const value_string bssap_sapi_values[] = {
{ 0x00, "RR/MM/CC" },
{ 0x03, "SMS" },
{ 0, NULL } };
static const value_string bsap_sapi_values[] = {
{ 0x00, "Not used" },
{ 0, NULL } };
/* Initialize the protocol and registered fields */
static int proto_bssap = -1;
static int hf_bssap_pdu_type = -1;
static int hf_bsap_pdu_type = -1;
static int hf_bssap_dlci_cc = -1;
static int hf_bsap_dlci_cc = -1;
static int hf_bssap_dlci_spare = -1;
static int hf_bsap_dlci_rsvd = -1;
static int hf_bssap_dlci_sapi = -1;
static int hf_bsap_dlci_sapi = -1;
static int hf_bssap_length = -1;
/* Initialize the subtree pointers */
static gint ett_bssap = -1;
static gint ett_bssap_dlci = -1;
static dissector_handle_t data_handle;
static dissector_table_t bssap_dissector_table;
static dissector_table_t bsap_dissector_table;
/*
* Keep track of pdu_type so we can call appropriate sub-dissector
*/
static guint8 pdu_type = 0xFF;
static guint bssap_or_bsap_global = BSSAP_OR_BSAP_DEFAULT;
static void
dissect_bssap_unknown_message(tvbuff_t *message_tvb, proto_tree *bssap_tree)
{
guint32 message_length;
message_length = tvb_length(message_tvb);
proto_tree_add_text(bssap_tree, message_tvb, 0, message_length,
"Unknown message (%u byte%s)",
message_length, plurality(message_length, "", "s"));
}
static void
dissect_bssap_unknown_param(tvbuff_t *tvb, proto_tree *tree, guint8 type, guint16 length)
{
proto_tree_add_text(tree, tvb, 0, length,
"Unknown parameter 0x%x (%u byte%s)",
type, length, plurality(length, "", "s"));
}
static void
dissect_bssap_data_param(tvbuff_t *tvb, packet_info *pinfo,
proto_tree *bssap_tree, proto_tree *tree)
{
if ((pdu_type <= 0x01))
{
if (bssap_or_bsap_global == BSSAP)
{
/* BSSAP */
if (dissector_try_port(bssap_dissector_table, pdu_type, tvb, pinfo, tree)) return;
}
else
{
/* BSAP */
if (dissector_try_port(bsap_dissector_table, pdu_type, tvb, pinfo, tree)) return;
}
}
/* No sub-dissection occured, treat it as raw data */
call_dissector(data_handle, tvb, pinfo, bssap_tree);
}
static void
dissect_bssap_dlci_param(tvbuff_t *tvb, proto_tree *tree, guint16 length)
{
proto_item *dlci_item = 0;
proto_tree *dlci_tree = 0;
guint8 oct;
dlci_item =
proto_tree_add_text(tree, tvb, 0, length,
"Data Link Connection Identifier");
dlci_tree = proto_item_add_subtree(dlci_item, ett_bssap_dlci);
oct = tvb_get_guint8(tvb, 0);
if (bssap_or_bsap_global == BSSAP)
{
proto_tree_add_uint(dlci_tree, hf_bssap_dlci_cc, tvb, 0, length, oct);
proto_tree_add_uint(dlci_tree, hf_bssap_dlci_spare, tvb, 0, length, oct);
proto_tree_add_uint(dlci_tree, hf_bssap_dlci_sapi, tvb, 0, length, oct);
}
else
{
proto_tree_add_uint(dlci_tree, hf_bsap_dlci_cc, tvb, 0, length, oct);
proto_tree_add_uint(dlci_tree, hf_bsap_dlci_rsvd, tvb, 0, length, oct);
proto_tree_add_uint(dlci_tree, hf_bsap_dlci_sapi, tvb, 0, length, oct);
}
}
static void
dissect_bssap_length_param(tvbuff_t *tvb, proto_tree *tree, guint16 length)
{
guint8 data_length;
data_length = tvb_get_guint8(tvb, 0);
proto_tree_add_uint(tree, hf_bssap_length, tvb, 0, length, data_length);
}
/*
* Dissect a parameter given its type, offset into tvb, and length.
*/
static guint16
dissect_bssap_parameter(tvbuff_t *tvb, packet_info *pinfo, proto_tree *bssap_tree,
proto_tree *tree, guint8 parameter_type, gint offset,
guint16 parameter_length)
{
tvbuff_t *parameter_tvb;
parameter_tvb = tvb_new_subset(tvb, offset, parameter_length, parameter_length);
switch (parameter_type)
{
case PARAMETER_DLCI:
dissect_bssap_dlci_param(parameter_tvb, bssap_tree, parameter_length);
break;
case PARAMETER_LENGTH:
dissect_bssap_length_param(parameter_tvb, bssap_tree, parameter_length);
break;
case PARAMETER_DATA:
dissect_bssap_data_param(parameter_tvb, pinfo, bssap_tree, tree);
break;
default:
dissect_bssap_unknown_param(parameter_tvb, bssap_tree, parameter_type,
parameter_length);
break;
}
return(parameter_length);
}
static guint16
dissect_bssap_var_parameter(tvbuff_t *tvb, packet_info *pinfo,
proto_tree *bssap_tree, proto_tree *tree,
guint8 parameter_type, gint offset)
{
guint16 parameter_length;
guint8 length_length;
parameter_length = tvb_get_guint8(tvb, offset);
length_length = LENGTH_LENGTH;
offset += length_length;
dissect_bssap_parameter(tvb, pinfo, bssap_tree, tree, parameter_type,
offset, parameter_length);
return(parameter_length + length_length);
}
static void
dissect_bssap_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *bssap_tree,
proto_tree *tree)
{
gint offset = 0;
/*
* Extract the PDU type
*/
pdu_type = tvb_get_guint8(tvb, PDU_TYPE_OFFSET);
offset = PDU_TYPE_LENGTH;
if (bssap_tree)
{
/*
* add the message type to the protocol tree
*/
proto_tree_add_uint(bssap_tree,
(bssap_or_bsap_global == BSSAP) ? hf_bssap_pdu_type : hf_bsap_pdu_type,
tvb, PDU_TYPE_OFFSET, PDU_TYPE_LENGTH, pdu_type);
}
/* Starting a new message dissection */
switch (pdu_type)
{
case BSSAP_PDU_TYPE_BSSMAP:
offset += dissect_bssap_parameter(tvb, pinfo, bssap_tree, tree,
PARAMETER_LENGTH, offset,
LENGTH_LENGTH);
offset += dissect_bssap_var_parameter(tvb, pinfo, bssap_tree, tree,
PARAMETER_DATA,
(offset - LENGTH_LENGTH));
break;
case BSSAP_PDU_TYPE_DTAP:
offset += dissect_bssap_parameter(tvb, pinfo, bssap_tree, tree,
PARAMETER_DLCI,
offset, DLCI_LENGTH);
offset += dissect_bssap_parameter(tvb, pinfo, bssap_tree, tree,
PARAMETER_LENGTH, offset,
LENGTH_LENGTH);
offset += dissect_bssap_var_parameter(tvb, pinfo, bssap_tree, tree,
PARAMETER_DATA,
(offset - LENGTH_LENGTH));
break;
default:
if (check_col(pinfo->cinfo, COL_INFO))
{
col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
val_to_str(pdu_type, ((bssap_or_bsap_global == BSSAP) ?
bssap_pdu_type_acro_values : bsap_pdu_type_acro_values),
"Unknown"));
}
dissect_bssap_unknown_message(tvb, bssap_tree);
break;
}
}
static void
dissect_bssap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *bssap_item;
proto_tree *bssap_tree = NULL;
/*
* Make entry in the Protocol column on summary display
*/
if (check_col(pinfo->cinfo, COL_PROTOCOL))
{
col_set_str(pinfo->cinfo, COL_PROTOCOL, ((bssap_or_bsap_global == BSSAP) ? "BSSAP" : "BSAP"));
}
/*
* create the bssap protocol tree
*/
proto_tree_add_item_hidden(tree, proto_bssap, tvb, 0, -1, FALSE);
bssap_item = proto_tree_add_text(tree, tvb, 0, -1, (bssap_or_bsap_global == BSSAP) ? "BSSAP" : "BSAP");
bssap_tree = proto_item_add_subtree(bssap_item, ett_bssap);
/* dissect the message */
dissect_bssap_message(tvb, pinfo, bssap_tree, tree);
}
static gboolean
dissect_bssap_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
/* Is it a BSSAP/BSAP packet?
* If octet_1 == 0x00 and octet_2 == length(tvb) - 2
* or if octet_1 == 0x01 and octet_3 == length(tvb) - 3
* then we'll assume it is a bssap packet
*/
switch (tvb_get_guint8(tvb, 0))
{
case 0x00:
if (tvb_get_guint8(tvb, 1) != (tvb_length(tvb) - 2)) { return(FALSE); }
break;
case 0x01:
if (tvb_get_guint8(tvb, 2) != (tvb_length(tvb) - 3)) { return(FALSE); }
break;
default:
return(FALSE);
}
dissect_bssap(tvb, pinfo, tree);
return(TRUE);
}
/* Register the protocol with Ethereal */
void
proto_register_bssap(void)
{
module_t *bssap_module;
/* Setup list of header fields */
static hf_register_info hf[] = {
{ &hf_bssap_pdu_type,
{ "Message Type", "bssap.pdu_type",
FT_UINT8, BASE_HEX, VALS(bssap_pdu_type_values), 0x0,
"", HFILL}},
{ &hf_bsap_pdu_type,
{ "Message Type", "bsap.pdu_type",
FT_UINT8, BASE_HEX, VALS(bsap_pdu_type_values), 0x0,
"", HFILL}},
{ &hf_bssap_dlci_cc,
{ "Control Channel", "bssap.dlci.cc",
FT_UINT8, BASE_HEX, VALS(bssap_cc_values), CC_MASK,
"", HFILL}},
{ &hf_bsap_dlci_cc,
{ "Control Channel", "bsap.dlci.cc",
FT_UINT8, BASE_HEX, VALS(bsap_cc_values), CC_MASK,
"", HFILL}},
{ &hf_bssap_dlci_spare,
{ "Spare", "bssap.dlci.spare",
FT_UINT8, BASE_HEX, NULL, SPARE_MASK,
"", HFILL}},
{ &hf_bsap_dlci_rsvd,
{ "Reserved", "bsap.dlci.rsvd",
FT_UINT8, BASE_HEX, NULL, SPARE_MASK,
"", HFILL}},
{ &hf_bssap_dlci_sapi,
{ "SAPI", "bssap.dlci.sapi",
FT_UINT8, BASE_HEX, VALS(bssap_sapi_values), SAPI_MASK,
"", HFILL}},
{ &hf_bsap_dlci_sapi,
{ "SAPI", "bsap.dlci.sapi",
FT_UINT8, BASE_HEX, VALS(bsap_sapi_values), SAPI_MASK,
"", HFILL}},
{ &hf_bssap_length,
{ "Length", "bssap.length",
FT_UINT8, BASE_DEC, NULL, 0x0,
"", HFILL}},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_bssap,
&ett_bssap_dlci,
};
static enum_val_t bssap_or_bsap_options[] = {
{ "BSSAP", BSSAP },
{ "BSAP", BSAP },
{ NULL, 0 }
};
/* Register the protocol name and description */
proto_bssap = proto_register_protocol("BSSAP/BSAP", "BSSAP", "bssap");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_bssap, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
bssap_module = prefs_register_protocol(proto_bssap, NULL);
prefs_register_enum_preference(bssap_module,
"bsap_or_bssap",
"Identify to sub-dissector as",
"For the sake of sub-dissectors registering to accept data from the BSSAP/BSAP dissector, this defines whether it is identified as BSSAP or BSAP.",
&bssap_or_bsap_global,
bssap_or_bsap_options,
FALSE);
bssap_dissector_table = register_dissector_table("bssap.pdu_type", "BSSAP Message Type", FT_UINT8, BASE_DEC);
bsap_dissector_table = register_dissector_table("bsap.pdu_type", "BSAP Message Type", FT_UINT8, BASE_DEC);
}
void
proto_reg_handoff_bssap(void)
{
heur_dissector_add("sccp", dissect_bssap_heur, proto_bssap);
data_handle = find_dissector("data");
}
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