![Guy Harris](/assets/img/avatar_default.png)
dynamically-assigned "ett_" integer values, assigned by "proto_register_subtree_array()"; this: obviates the need to update "packet.h" whenever you add a new subtree type - you only have to add a call to "proto_register_subtree_array()" to a "register" routine and an array of pointers to "ett_", if they're not already there, and add a pointer to the new "ett_" variable to the array, if they are there; would allow run-time-loaded dissectors to allocate subtree types when they're loaded. svn path=/trunk/; revision=1043
198 lines
5.6 KiB
C
198 lines
5.6 KiB
C
/* packet-lapd.c
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* Routines for LAPD frame disassembly
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* Gilbert Ramirez <gram@xiexie.org>
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*
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* $Id: packet-lapd.c,v 1.3 1999/11/16 11:42:37 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@zing.org>
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* Copyright 1998
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*
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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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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.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 "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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/*
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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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void
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dissect_lapd(const u_char *pd, frame_data *fd, proto_tree *tree)
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{
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proto_tree *lapd_tree, *addr_tree;
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proto_item *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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if (check_col(fd, COL_PROTOCOL))
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col_add_str(fd, COL_PROTOCOL, "LAPD");
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address = pntohs(&pd[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 (fd->pseudo_header.lapd.from_network_to_user) {
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is_response = cr ? FALSE : TRUE;
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if(check_col(fd, COL_RES_DL_DST))
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col_add_str(fd, COL_RES_DL_DST, "User");
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if(check_col(fd, COL_RES_DL_SRC))
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col_add_str(fd, COL_RES_DL_SRC, "Network");
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}
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else {
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is_response = cr ? TRUE : FALSE;
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if(check_col(fd, COL_RES_DL_DST))
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col_add_str(fd, COL_RES_DL_DST, "Network");
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if(check_col(fd, COL_RES_DL_SRC))
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col_add_str(fd, COL_RES_DL_SRC, "User");
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}
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if (tree) {
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ti = proto_tree_add_item(tree, proto_lapd, 0, 3, NULL);
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lapd_tree = proto_item_add_subtree(ti, ett_lapd);
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ti = proto_tree_add_item(lapd_tree, hf_lapd_address, 0, 2, address);
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addr_tree = proto_item_add_subtree(ti, ett_lapd_address);
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proto_tree_add_item(addr_tree, hf_lapd_sapi, 0, 1, address);
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proto_tree_add_item(addr_tree, hf_lapd_cr, 0, 1, address);
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proto_tree_add_item(addr_tree, hf_lapd_ea1, 0, 1, address);
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proto_tree_add_item(addr_tree, hf_lapd_tei, 1, 1, address);
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proto_tree_add_item(addr_tree, hf_lapd_ea2, 1, 1, address);
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}
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else {
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lapd_tree = NULL;
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}
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control = dissect_xdlc_control(pd, 2, fd, 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 (XDLC_HAS_PAYLOAD(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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dissect_q931(pd, lapd_header_len, fd, tree);
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break;
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default:
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dissect_data(pd, lapd_header_len, fd, tree);
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break;
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}
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}
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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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"" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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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"" }},
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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)", "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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}
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