forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
than the p2p pseudo-header's "sent" field, in the LAPD dissector (the p2p pseudo-header isn't used for ISDN). Do something similar for the V.120 dissector (which currently will only be used in ISDN captures, but this makes it possible for it to handle other captures as well). svn path=/trunk/; revision=6522
218 lines
6.5 KiB
C
218 lines
6.5 KiB
C
/* packet-lapd.c
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* Routines for LAPD frame disassembly
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* Gilbert Ramirez <gram@alumni.rice.edu>
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*
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* $Id: packet-lapd.c,v 1.33 2002/10/31 07:43:10 guy 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
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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 <stdio.h>
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#include <glib.h>
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#include <string.h>
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#include <epan/packet.h>
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#include "xdlc.h"
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/* ISDN/LAPD references:
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*
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* http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/isdn.htm
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* http://www.ece.wpi.edu/courses/ee535/hwk11cd95/agrebe/agrebe.html
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* http://www.acacia-net.com/Clarinet/Protocol/q9213o84.htm
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*/
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static int proto_lapd = -1;
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static int hf_lapd_address = -1;
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static int hf_lapd_sapi = -1;
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static int hf_lapd_cr = -1;
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static int hf_lapd_ea1 = -1;
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static int hf_lapd_tei = -1;
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static int hf_lapd_ea2 = -1;
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static int hf_lapd_control = -1;
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static gint ett_lapd = -1;
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static gint ett_lapd_address = -1;
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static gint ett_lapd_control = -1;
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static dissector_handle_t q931_handle;
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static dissector_handle_t data_handle;
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/*
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* Bits in the address field.
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*/
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#define LAPD_SAPI 0xfc00 /* Service Access Point Identifier */
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#define LAPD_SAPI_SHIFT 10
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#define LAPD_CR 0x0200 /* Command/Response bit */
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#define LAPD_EA1 0x0100 /* First Address Extension bit */
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#define LAPD_TEI 0x00fe /* Terminal Endpoint Identifier */
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#define LAPD_EA2 0x0001 /* Second Address Extension bit */
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#define LAPD_SAPI_Q931 0 /* Q.931 call control procedure */
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#define LAPD_SAPI_PM_Q931 1 /* Packet mode Q.931 call control procedure */
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#define LAPD_SAPI_X25 16 /* X.25 Level 3 procedures */
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#define LAPD_SAPI_L2 63 /* Layer 2 management procedures */
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static const value_string lapd_sapi_vals[] = {
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{ LAPD_SAPI_Q931, "Q.931 Call control procedure" },
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{ LAPD_SAPI_PM_Q931, "Packet mode Q.931 Call control procedure" },
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{ LAPD_SAPI_X25, "X.25 Level 3 procedures" },
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{ LAPD_SAPI_L2, "Layer 2 management procedures" },
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{ 0, NULL }
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};
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static void
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dissect_lapd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *lapd_tree, *addr_tree;
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proto_item *lapd_ti, *addr_ti;
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guint16 control;
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int lapd_header_len;
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guint16 address, cr, sapi;
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gboolean is_response;
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tvbuff_t *next_tvb;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "LAPD");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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address = tvb_get_ntohs(tvb, 0);
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cr = address & LAPD_CR;
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sapi = (address & LAPD_SAPI) >> LAPD_SAPI_SHIFT;
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lapd_header_len = 2; /* address */
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if (pinfo->p2p_dir == P2P_DIR_SENT) {
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is_response = cr ? TRUE : FALSE;
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if(check_col(pinfo->cinfo, COL_RES_DL_DST))
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "Network");
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if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "User");
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}
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else {
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/* XXX - what if the direction is unknown? */
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is_response = cr ? FALSE : TRUE;
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if(check_col(pinfo->cinfo, COL_RES_DL_DST))
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "User");
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if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "Network");
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}
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if (tree) {
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lapd_ti = proto_tree_add_item(tree, proto_lapd, tvb, 0, -1,
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FALSE);
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lapd_tree = proto_item_add_subtree(lapd_ti, ett_lapd);
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addr_ti = proto_tree_add_uint(lapd_tree, hf_lapd_address, tvb,
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0, 2, address);
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addr_tree = proto_item_add_subtree(addr_ti, ett_lapd_address);
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proto_tree_add_uint(addr_tree, hf_lapd_sapi,tvb, 0, 1, address);
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proto_tree_add_uint(addr_tree, hf_lapd_cr, tvb, 0, 1, address);
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proto_tree_add_uint(addr_tree, hf_lapd_ea1, tvb, 0, 1, address);
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proto_tree_add_uint(addr_tree, hf_lapd_tei, tvb, 1, 1, address);
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proto_tree_add_uint(addr_tree, hf_lapd_ea2, tvb, 1, 1, address);
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}
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else {
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lapd_ti = NULL;
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lapd_tree = NULL;
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}
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control = dissect_xdlc_control(tvb, 2, pinfo, lapd_tree, hf_lapd_control,
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ett_lapd_control, is_response, TRUE);
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lapd_header_len += XDLC_CONTROL_LEN(control, TRUE);
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if (tree)
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proto_item_set_len(lapd_ti, lapd_header_len);
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next_tvb = tvb_new_subset(tvb, lapd_header_len, -1, -1);
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if (XDLC_IS_INFORMATION(control)) {
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/* call next protocol */
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switch (sapi) {
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case LAPD_SAPI_Q931:
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call_dissector(q931_handle, next_tvb, pinfo, tree);
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break;
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default:
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call_dissector(data_handle,next_tvb, pinfo, tree);
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break;
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}
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} else
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call_dissector(data_handle,next_tvb, pinfo, tree);
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}
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void
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proto_register_lapd(void)
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{
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static hf_register_info hf[] = {
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{ &hf_lapd_address,
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{ "Address Field", "lapd.address", FT_UINT16, BASE_HEX, NULL, 0x0,
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"Address", HFILL }},
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{ &hf_lapd_sapi,
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{ "SAPI", "lapd.sapi", FT_UINT16, BASE_DEC, VALS(lapd_sapi_vals), LAPD_SAPI,
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"Service Access Point Identifier", HFILL }},
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{ &hf_lapd_cr,
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{ "C/R", "lapd.cr", FT_UINT16, BASE_DEC, NULL, LAPD_CR,
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"Command/Response bit", HFILL }},
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{ &hf_lapd_ea1,
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{ "EA1", "lapd.ea1", FT_UINT16, BASE_DEC, NULL, LAPD_EA1,
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"First Address Extension bit", HFILL }},
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{ &hf_lapd_tei,
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{ "TEI", "lapd.tei", FT_UINT16, BASE_DEC, NULL, LAPD_TEI,
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"Terminal Endpoint Identifier", HFILL }},
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{ &hf_lapd_ea2,
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{ "EA2", "lapd.ea2", FT_UINT16, BASE_DEC, NULL, LAPD_EA2,
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"Second Address Extension bit", HFILL }},
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{ &hf_lapd_control,
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{ "Control Field", "lapd.control", FT_UINT16, BASE_HEX, NULL, 0x0,
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"Control field", HFILL }},
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};
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static gint *ett[] = {
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&ett_lapd,
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&ett_lapd_address,
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&ett_lapd_control,
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};
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proto_lapd = proto_register_protocol("Link Access Procedure, Channel D (LAPD)",
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"LAPD", "lapd");
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proto_register_field_array (proto_lapd, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_dissector("lapd", dissect_lapd, proto_lapd);
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}
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void
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proto_reg_handoff_lapd(void)
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{
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/*
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* Get handle for the Q.931 dissector.
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*/
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q931_handle = find_dissector("q931");
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data_handle = find_dissector("data");
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}
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