forked from osmocom/wireshark
220 lines
7.2 KiB
C
220 lines
7.2 KiB
C
/* packet-mtp2.c
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* Routines for MTP2 dissection
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* It is hopefully (needs testing) compliant to
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* ITU-T Q.703
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*
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* Copyright 2001, Michael Tuexen <tuexen [AT] fh-muenster.de>
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*
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* $Id: packet-mtp2.c,v 1.10 2003/12/21 05:51:33 jmayer Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* Copied from packet-m2pa.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <glib.h>
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#include <epan/packet.h>
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#define LITTLE_ENDIAN_BYTE_ORDER TRUE
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/* Initialize the protocol and registered fields */
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static int proto_mtp2 = -1;
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static int hf_mtp2_bsn = -1;
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static int hf_mtp2_bib = -1;
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static int hf_mtp2_fsn = -1;
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static int hf_mtp2_fib = -1;
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static int hf_mtp2_li = -1;
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static int hf_mtp2_spare = -1;
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static int hf_mtp2_sf = -1;
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static int hf_mtp2_long_sf = -1;
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/* Initialize the subtree pointers */
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static gint ett_mtp2 = -1;
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static dissector_handle_t mtp3_handle;
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static int mtp3_proto_id;
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#define BSN_BIB_LENGTH 1
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#define FSN_FIB_LENGTH 1
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#define LI_LENGTH 1
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#define HEADER_LENGTH (BSN_BIB_LENGTH + FSN_FIB_LENGTH + LI_LENGTH)
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#define BSN_BIB_OFFSET 0
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#define FSN_FIB_OFFSET (BSN_BIB_OFFSET + BSN_BIB_LENGTH)
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#define LI_OFFSET (FSN_FIB_OFFSET + FSN_FIB_LENGTH)
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#define SIO_OFFSET (LI_OFFSET + LI_LENGTH)
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#define BSN_MASK 0x7f
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#define BIB_MASK 0x80
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#define FSN_MASK 0x7f
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#define FIB_MASK 0x80
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#define LI_MASK 0x3f
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#define SPARE_MASK 0xc0
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static void
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dissect_mtp2_header(tvbuff_t *su_tvb, proto_item *mtp2_tree)
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{
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if (mtp2_tree) {
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proto_tree_add_item(mtp2_tree, hf_mtp2_bsn, su_tvb, BSN_BIB_OFFSET, BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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proto_tree_add_item(mtp2_tree, hf_mtp2_bib, su_tvb, BSN_BIB_OFFSET, BSN_BIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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proto_tree_add_item(mtp2_tree, hf_mtp2_fsn, su_tvb, FSN_FIB_OFFSET, FSN_FIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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proto_tree_add_item(mtp2_tree, hf_mtp2_fib, su_tvb, FSN_FIB_OFFSET, FSN_FIB_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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proto_tree_add_item(mtp2_tree, hf_mtp2_li, su_tvb, LI_OFFSET, LI_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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proto_tree_add_item(mtp2_tree, hf_mtp2_spare, su_tvb, LI_OFFSET, LI_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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}
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}
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static void
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dissect_mtp2_fisu(packet_info *pinfo)
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{
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if (check_col(pinfo->cinfo, COL_INFO))
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col_set_str(pinfo->cinfo, COL_INFO, "FISU ");
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}
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static const value_string status_field_vals[] = {
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{ 0x0, "Status Indication O" },
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{ 0x1, "Status Indication N" },
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{ 0x2, "Status Indication E" },
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{ 0x3, "Status Indication OS" },
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{ 0x4, "Status Indication PO" },
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{ 0x5, "Status Indication BO" },
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{ 0, NULL}
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};
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#define SF_OFFSET (LI_OFFSET + LI_LENGTH)
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#define SF_LENGTH 1
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#define LONG_SF_LENGTH 2
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static void
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dissect_mtp2_lssu(tvbuff_t *su_tvb, packet_info *pinfo, proto_item *mtp2_tree)
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{
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guint8 li;
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if (check_col(pinfo->cinfo, COL_INFO))
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col_set_str(pinfo->cinfo, COL_INFO, "LSSU ");
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if (mtp2_tree) {
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li = tvb_get_guint8(su_tvb, LI_OFFSET);
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if ((li & LI_MASK) == 1)
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proto_tree_add_item(mtp2_tree, hf_mtp2_sf, su_tvb, SF_OFFSET, SF_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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else
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proto_tree_add_item(mtp2_tree, hf_mtp2_long_sf, su_tvb, SF_OFFSET, LONG_SF_LENGTH, LITTLE_ENDIAN_BYTE_ORDER);
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}
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}
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static void
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dissect_mtp2_msu(tvbuff_t *su_tvb, packet_info *pinfo, proto_item *mtp2_item, proto_item *tree)
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{
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gint sif_sio_length;
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tvbuff_t *sif_sio_tvb;
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if (check_col(pinfo->cinfo, COL_INFO))
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col_set_str(pinfo->cinfo, COL_INFO, "MSU ");
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sif_sio_length = tvb_length(su_tvb) - HEADER_LENGTH;
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sif_sio_tvb = tvb_new_subset(su_tvb, SIO_OFFSET, sif_sio_length, sif_sio_length);
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call_dissector(mtp3_handle, sif_sio_tvb, pinfo, tree);
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if (tree)
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proto_item_set_len(mtp2_item, HEADER_LENGTH);
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}
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static void
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dissect_mtp2_su(tvbuff_t *su_tvb, packet_info *pinfo, proto_item *mtp2_item, proto_item *mtp2_tree, proto_tree *tree)
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{
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guint8 li;
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dissect_mtp2_header(su_tvb, mtp2_tree);
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li = tvb_get_guint8(su_tvb, LI_OFFSET);
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switch(li & LI_MASK) {
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case 0:
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dissect_mtp2_fisu(pinfo);
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break;
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case 1:
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case 2:
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dissect_mtp2_lssu(su_tvb, pinfo, mtp2_tree);
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break;
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default:
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dissect_mtp2_msu(su_tvb, pinfo, mtp2_item, tree);
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break;
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}
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}
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static void
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dissect_mtp2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_item *mtp2_item = NULL;
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proto_tree *mtp2_tree = NULL;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "MTP2");
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if (tree) {
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mtp2_item = proto_tree_add_item(tree, proto_mtp2, tvb, 0, -1, FALSE);
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mtp2_tree = proto_item_add_subtree(mtp2_item, ett_mtp2);
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};
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dissect_mtp2_su(tvb, pinfo, mtp2_item, mtp2_tree, tree);
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}
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void
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proto_register_mtp2(void)
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{
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static hf_register_info hf[] = {
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{ &hf_mtp2_bsn, { "Backward sequence number", "mtp2.bsn", FT_UINT8, BASE_DEC, NULL, BSN_MASK, "", HFILL } },
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{ &hf_mtp2_bib, { "Backward indicator bit", "mtp2.bib", FT_UINT8, BASE_DEC, NULL, BIB_MASK, "", HFILL } },
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{ &hf_mtp2_fsn, { "Forward sequence number", "mtp2.fsn", FT_UINT8, BASE_DEC, NULL, FSN_MASK, "", HFILL } },
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{ &hf_mtp2_fib, { "Forward indicator bit", "mtp2.fib", FT_UINT8, BASE_DEC, NULL, FIB_MASK, "", HFILL } },
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{ &hf_mtp2_li, { "Length Indicator", "mtp2.li", FT_UINT8, BASE_DEC, NULL, LI_MASK, "", HFILL } },
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{ &hf_mtp2_spare, { "Spare", "mtp2.spare", FT_UINT8, BASE_DEC, NULL, SPARE_MASK, "", HFILL } },
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{ &hf_mtp2_sf, { "Status field", "mtp2.sf", FT_UINT8, BASE_DEC, VALS(status_field_vals), 0x0, "", HFILL } },
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{ &hf_mtp2_long_sf, { "Status field", "mtp2.sf", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL } }
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};
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static gint *ett[] = {
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&ett_mtp2
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};
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proto_mtp2 = proto_register_protocol("Message Transfer Part Level 2", "MTP2", "mtp2");
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register_dissector("mtp2", dissect_mtp2, proto_mtp2);
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proto_register_field_array(proto_mtp2, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_mtp2(void)
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{
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dissector_handle_t mtp2_handle;
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mtp2_handle = create_dissector_handle(dissect_mtp2, proto_mtp2);
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dissector_add("wtap_encap", WTAP_ENCAP_MTP2, mtp2_handle);
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mtp3_handle = find_dissector("mtp3");
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mtp3_proto_id = proto_get_id_by_filter_name("mtp3");
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}
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