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/* packet-mtp2.c
* Routines for MTP2 dissection
* It is hopefully (needs testing) compliant to
* ITU-T Q.703 and Q.703 Annex A.
*
* Copyright 2001, 2004 Michael Tuexen <tuexen [AT] fh-muenster.de>
*
* $Id$
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* Copyright 1998 Gerald Combs
*
* Copied from packet-m2pa.c
*
* 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 <glib.h>
#include <epan/packet.h>
#include "epan/prefs.h"
#define LITTLE_ENDIAN_BYTE_ORDER TRUE
/* Initialize the protocol and registered fields */
static int proto_mtp2 = -1;
static int hf_mtp2_bsn = -1;
static int hf_mtp2_ext_bsn = -1;
static int hf_mtp2_ext_res = -1;
static int hf_mtp2_bib = -1;
static int hf_mtp2_ext_bib = -1;
static int hf_mtp2_fsn = -1;
static int hf_mtp2_ext_fsn = -1;
static int hf_mtp2_fib = -1;
static int hf_mtp2_ext_fib = -1;
static int hf_mtp2_li = -1;
static int hf_mtp2_ext_li = -1;
static int hf_mtp2_spare = -1;
static int hf_mtp2_ext_spare = -1;
static int hf_mtp2_sf = -1;
static int hf_mtp2_long_sf = -1;
/* Initialize the subtree pointers */
static gint ett_mtp2 = -1;
static dissector_handle_t mtp3_handle;
static int mtp3_proto_id;
static gboolean use_extended_sequence_numbers_default = FALSE;
static gboolean use_extended_sequence_numbers = FALSE;
#define BSN_BIB_LENGTH 1
#define FSN_FIB_LENGTH 1
#define LI_LENGTH 1
#define HEADER_LENGTH (BSN_BIB_LENGTH + FSN_FIB_LENGTH + LI_LENGTH)
#define EXTENDED_BSN_BIB_LENGTH 2
#define EXTENDED_FSN_FIB_LENGTH 2
#define EXTENDED_LI_LENGTH 2
#define EXTENDED_HEADER_LENGTH (EXTENDED_BSN_BIB_LENGTH + EXTENDED_FSN_FIB_LENGTH + EXTENDED_LI_LENGTH)
#define BSN_BIB_OFFSET 0
#define FSN_FIB_OFFSET (BSN_BIB_OFFSET + BSN_BIB_LENGTH)
#define LI_OFFSET (FSN_FIB_OFFSET + FSN_FIB_LENGTH)
#define SIO_OFFSET (LI_OFFSET + LI_LENGTH)
#define EXTENDED_BSN_BIB_OFFSET 0
#define EXTENDED_FSN_FIB_OFFSET (EXTENDED_BSN_BIB_OFFSET + EXTENDED_BSN_BIB_LENGTH)
#define EXTENDED_LI_OFFSET (EXTENDED_FSN_FIB_OFFSET + EXTENDED_FSN_FIB_LENGTH)
#define EXTENDED_SIO_OFFSET (EXTENDED_LI_OFFSET + EXTENDED_LI_LENGTH)
#define BSN_MASK 0x7f
#define BIB_MASK 0x80
#define FSN_MASK 0x7f
#define FIB_MASK 0x80
#define LI_MASK 0x3f
#define SPARE_MASK 0xc0
#define EXTENDED_BSN_MASK 0x0fff
#define EXTENDED_RES_MASK 0x7000
#define EXTENDED_BIB_MASK 0x8000
#define EXTENDED_FSN_MASK 0x0fff
#define EXTENDED_FIB_MASK 0x8000
#define EXTENDED_LI_MASK 0x01ff
#define EXTENDED_SPARE_MASK 0xfe00
static void
dissect_mtp2_header(tvbuff_t *su_tvb, proto_item *mtp2_tree)
{
if (mtp2_tree) {
if (use_extended_sequence_numbers) {
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_bsn, su_tvb, EXTENDED_BSN_BIB_OFFSET, EXTENDED_BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_res, su_tvb, EXTENDED_BSN_BIB_OFFSET, EXTENDED_BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_bib, su_tvb, EXTENDED_BSN_BIB_OFFSET, EXTENDED_BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_fsn, su_tvb, EXTENDED_FSN_FIB_OFFSET, EXTENDED_FSN_FIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_res, su_tvb, EXTENDED_BSN_BIB_OFFSET, EXTENDED_BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_fib, su_tvb, EXTENDED_FSN_FIB_OFFSET, EXTENDED_FSN_FIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_li, su_tvb, EXTENDED_LI_OFFSET, EXTENDED_LI_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_ext_spare, su_tvb, EXTENDED_LI_OFFSET, EXTENDED_LI_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
} else {
proto_tree_add_item(mtp2_tree, hf_mtp2_bsn, su_tvb, BSN_BIB_OFFSET, BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_bib, su_tvb, BSN_BIB_OFFSET, BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_fsn, su_tvb, FSN_FIB_OFFSET, FSN_FIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_fib, su_tvb, FSN_FIB_OFFSET, FSN_FIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_li, su_tvb, LI_OFFSET, LI_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
proto_tree_add_item(mtp2_tree, hf_mtp2_spare, su_tvb, LI_OFFSET, LI_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
}
}
}
static void
dissect_mtp2_fisu(packet_info *pinfo)
{
if (check_col(pinfo->cinfo, COL_INFO))
col_set_str(pinfo->cinfo, COL_INFO, "FISU ");
}
static const value_string status_field_vals[] = {
{ 0x0, "Status Indication O" },
{ 0x1, "Status Indication N" },
{ 0x2, "Status Indication E" },
{ 0x3, "Status Indication OS" },
{ 0x4, "Status Indication PO" },
{ 0x5, "Status Indication BO" },
{ 0, NULL}
};
#define SF_OFFSET (LI_OFFSET + LI_LENGTH)
#define EXTENDED_SF_OFFSET (EXTENDED_LI_OFFSET + EXTENDED_LI_LENGTH)
#define SF_LENGTH 1
#define LONG_SF_LENGTH 2
static void
dissect_mtp2_lssu(tvbuff_t *su_tvb, packet_info *pinfo, proto_item *mtp2_tree)
{
if (check_col(pinfo->cinfo, COL_INFO))
col_set_str(pinfo->cinfo, COL_INFO, "LSSU ");
if (mtp2_tree) {
if (use_extended_sequence_numbers) {
if ((tvb_get_letohs(su_tvb, EXTENDED_LI_OFFSET) & EXTENDED_LI_MASK) == 1)
proto_tree_add_item(mtp2_tree, hf_mtp2_sf, su_tvb, EXTENDED_SF_OFFSET, SF_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
else
proto_tree_add_item(mtp2_tree, hf_mtp2_long_sf, su_tvb, EXTENDED_SF_OFFSET, LONG_SF_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
} else {
if ((tvb_get_guint8(su_tvb, LI_OFFSET) & LI_MASK) == 1)
proto_tree_add_item(mtp2_tree, hf_mtp2_sf, su_tvb, SF_OFFSET, SF_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
else
proto_tree_add_item(mtp2_tree, hf_mtp2_long_sf, su_tvb, SF_OFFSET, LONG_SF_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
}
}
}
static void
dissect_mtp2_msu(tvbuff_t *su_tvb, packet_info *pinfo, proto_item *mtp2_item, proto_item *tree)
{
gint sif_sio_length;
tvbuff_t *sif_sio_tvb;
if (check_col(pinfo->cinfo, COL_INFO))
col_set_str(pinfo->cinfo, COL_INFO, "MSU ");
if (use_extended_sequence_numbers) {
sif_sio_length = tvb_length(su_tvb) - EXTENDED_HEADER_LENGTH;
sif_sio_tvb = tvb_new_subset(su_tvb, EXTENDED_SIO_OFFSET, sif_sio_length, sif_sio_length);
} else {
sif_sio_length = tvb_length(su_tvb) - HEADER_LENGTH;
sif_sio_tvb = tvb_new_subset(su_tvb, SIO_OFFSET, sif_sio_length, sif_sio_length);
}
call_dissector(mtp3_handle, sif_sio_tvb, pinfo, tree);
if (tree) {
if (use_extended_sequence_numbers)
proto_item_set_len(mtp2_item, EXTENDED_HEADER_LENGTH);
else
proto_item_set_len(mtp2_item, HEADER_LENGTH);
}
}
static void
dissect_mtp2_su(tvbuff_t *su_tvb, packet_info *pinfo, proto_item *mtp2_item, proto_item *mtp2_tree, proto_tree *tree)
{
guint16 li;
dissect_mtp2_header(su_tvb, mtp2_tree);
if (use_extended_sequence_numbers)
li = tvb_get_letohs(su_tvb, EXTENDED_LI_OFFSET) & EXTENDED_LI_MASK;
else
li = tvb_get_guint8(su_tvb, LI_OFFSET) & LI_MASK;
switch(li) {
case 0:
dissect_mtp2_fisu(pinfo);
break;
case 1:
case 2:
dissect_mtp2_lssu(su_tvb, pinfo, mtp2_tree);
break;
default:
dissect_mtp2_msu(su_tvb, pinfo, mtp2_item, tree);
break;
}
}
static void
dissect_mtp2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *mtp2_item = NULL;
proto_tree *mtp2_tree = NULL;
if (pinfo->annex_a_used == MTP2_ANNEX_A_USED_UNKNOWN)
use_extended_sequence_numbers = use_extended_sequence_numbers_default;
else
use_extended_sequence_numbers = (pinfo->annex_a_used == MTP2_ANNEX_A_USED);
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "MTP2");
if (tree) {
mtp2_item = proto_tree_add_item(tree, proto_mtp2, tvb, 0, -1, FALSE);
mtp2_tree = proto_item_add_subtree(mtp2_item, ett_mtp2);
};
dissect_mtp2_su(tvb, pinfo, mtp2_item, mtp2_tree, tree);
}
void
proto_register_mtp2(void)
{
static hf_register_info hf[] = {
{ &hf_mtp2_bsn, { "Backward sequence number", "mtp2.bsn", FT_UINT8, BASE_DEC, NULL, BSN_MASK, "", HFILL } },
{ &hf_mtp2_ext_bsn, { "Backward sequence number", "mtp2.bsn", FT_UINT16, BASE_DEC, NULL, EXTENDED_BSN_MASK, "", HFILL } },
{ &hf_mtp2_ext_res, { "Reserved", "mtp2.res", FT_UINT16, BASE_DEC, NULL, EXTENDED_RES_MASK, "", HFILL } },
{ &hf_mtp2_bib, { "Backward indicator bit", "mtp2.bib", FT_UINT8, BASE_DEC, NULL, BIB_MASK, "", HFILL } },
{ &hf_mtp2_ext_bib, { "Backward indicator bit", "mtp2.bib", FT_UINT16, BASE_DEC, NULL, EXTENDED_BIB_MASK, "", HFILL } },
{ &hf_mtp2_fsn, { "Forward sequence number", "mtp2.fsn", FT_UINT8, BASE_DEC, NULL, FSN_MASK, "", HFILL } },
{ &hf_mtp2_ext_fsn, { "Forward sequence number", "mtp2.fsn", FT_UINT16, BASE_DEC, NULL, EXTENDED_FSN_MASK, "", HFILL } },
{ &hf_mtp2_fib, { "Forward indicator bit", "mtp2.fib", FT_UINT8, BASE_DEC, NULL, FIB_MASK, "", HFILL } },
{ &hf_mtp2_ext_fib, { "Forward indicator bit", "mtp2.fib", FT_UINT16, BASE_DEC, NULL, EXTENDED_FIB_MASK, "", HFILL } },
{ &hf_mtp2_li, { "Length Indicator", "mtp2.li", FT_UINT8, BASE_DEC, NULL, LI_MASK, "", HFILL } },
{ &hf_mtp2_ext_li, { "Length Indicator", "mtp2.li", FT_UINT16, BASE_DEC, NULL, EXTENDED_LI_MASK, "", HFILL } },
{ &hf_mtp2_spare, { "Spare", "mtp2.spare", FT_UINT8, BASE_DEC, NULL, SPARE_MASK, "", HFILL } },
{ &hf_mtp2_ext_spare, { "Spare", "mtp2.spare", FT_UINT16, BASE_DEC, NULL, EXTENDED_SPARE_MASK, "", HFILL } },
{ &hf_mtp2_sf, { "Status field", "mtp2.sf", FT_UINT8, BASE_DEC, VALS(status_field_vals), 0x0, "", HFILL } },
{ &hf_mtp2_long_sf, { "Status field", "mtp2.sf", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL } }
};
static gint *ett[] = {
&ett_mtp2
};
module_t *mtp2_module;
proto_mtp2 = proto_register_protocol("Message Transfer Part Level 2", "MTP2", "mtp2");
register_dissector("mtp2", dissect_mtp2, proto_mtp2);
proto_register_field_array(proto_mtp2, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
mtp2_module = prefs_register_protocol(proto_mtp2, NULL);
prefs_register_bool_preference(mtp2_module,
"use_extended_sequence_numbers",
"Use extended sequence numbers",
"Whether the MTP2 dissector should use extended sequence numbers as described in Q.703, Annex A as a default.",
&use_extended_sequence_numbers_default);
}
void
proto_reg_handoff_mtp2(void)
{
dissector_handle_t mtp2_handle;
mtp2_handle = create_dissector_handle(dissect_mtp2, proto_mtp2);
dissector_add("wtap_encap", WTAP_ENCAP_MTP2, mtp2_handle);
dissector_add("wtap_encap", WTAP_ENCAP_MTP2_WITH_PHDR, mtp2_handle);
mtp3_handle = find_dissector("mtp3");
mtp3_proto_id = proto_get_id_by_filter_name("mtp3");
}
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