2012-08-02 21:53:47 +00:00
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/* packet-ax25-nol3.c
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*
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* Routines for Amateur Packet Radio protocol dissection
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* Copyright 2007,2008,2009,2010,2012 R.W. Stearn <richard@rns-stearn.demon.co.uk>
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*
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* $Id$
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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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* 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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/*
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* This dissector is for the "No Layer 3 protocol" PID of the AX.25 Amateur
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* Packet-Radio Link-Layer Protocol, Version 2.0, October 1984
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2012-08-02 22:04:12 +00:00
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*
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2012-08-02 21:53:47 +00:00
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* At the time of writing the specification could be found here:
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* http://www.tapr.org/pub_ax25.html
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*
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* Information on the "protocols" recognised by this dissector are drawn from:
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* DX cluster:
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* A network capture kindly donated by Luca Melette.
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2012-08-02 22:40:02 +00:00
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* APRS:
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* http://www.aprs.org/
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2012-08-02 21:53:47 +00:00
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*
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* Inspiration on how to build the dissector drawn from
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* packet-sdlc.c
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* packet-x25.c
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* packet-lapb.c
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* paket-gprs-llc.c
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* xdlc.c
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* with the base file built from README.developers.
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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 <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <math.h>
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#include <glib.h>
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#include <epan/strutil.h>
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#include <epan/emem.h>
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2012-08-03 01:58:12 +00:00
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#include <epan/ax25_pids.h>
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2012-08-02 21:53:47 +00:00
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#define STRLEN 80
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/* Forward declaration we need below */
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void proto_reg_handoff_ax25_nol3(void);
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/* Dissector handles - all the possibles are listed */
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2012-08-02 22:40:02 +00:00
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static dissector_handle_t aprs_handle;
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2012-08-02 21:53:47 +00:00
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static dissector_handle_t default_handle;
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/* Initialize the protocol and registered fields */
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static int proto_ax25_nol3 = -1;
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static int proto_dx = -1;
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static int hf_dx_report = -1;
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static int hf_text = -1;
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/* Global preferences */
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2012-08-02 22:40:02 +00:00
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static gboolean gPREF_APRS = FALSE;
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2012-08-02 21:53:47 +00:00
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static gboolean gPREF_DX = FALSE;
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/* Initialize the subtree pointers */
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static gint ett_ax25_nol3 = -1;
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static gint ett_dx = -1;
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/* Code to actually dissect the packets */
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static void
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dissect_dx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
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{
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proto_item *ti;
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proto_tree *dx_tree;
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int data_len;
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int offset;
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offset = 0;
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data_len = tvb_length_remaining( tvb, offset );
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col_set_str( pinfo->cinfo, COL_PROTOCOL, "DX" );
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col_clear( pinfo->cinfo, COL_INFO );
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col_add_fstr( pinfo->cinfo, COL_INFO, "%s", tvb_format_text( tvb, offset, 15 ) );
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if ( parent_tree )
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{
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/* create display subtree for the protocol */
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ti = proto_tree_add_protocol_format( parent_tree, proto_dx, tvb, 0, tvb_length_remaining( tvb, offset ),
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"DX (%s)", tvb_format_text( tvb, offset, 15 ) );
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dx_tree = proto_item_add_subtree( ti, ett_dx );
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offset = 0;
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proto_tree_add_item( dx_tree, hf_dx_report, tvb, offset, data_len, FALSE );
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}
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}
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2012-08-02 22:40:02 +00:00
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static gboolean
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isaprs( guint8 dti )
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{
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gboolean b = FALSE;
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switch ( dti )
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{
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case '<' :
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case '>' :
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case '?' :
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case '$' :
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case '%' :
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case 'T' :
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case '[' :
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case ')' :
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case '_' :
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case ',' :
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case '{' :
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case '}' :
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case ':' :
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case ';' :
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case 0x1c :
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case 0x1d :
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case '\'' :
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case '`' :
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case '#' :
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case '*' :
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case '&' :
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case '+' :
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case '.' :
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case '=' :
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case '!' :
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case '@' :
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case '/' : b = TRUE; break;
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default : break;
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}
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return b;
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}
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2012-08-02 21:53:47 +00:00
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static void
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dissect_ax25_nol3(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree )
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{
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proto_item *ti;
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proto_tree *ax25_nol3_tree;
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char *info_buffer;
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int offset;
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void *saved_private_data;
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tvbuff_t *next_tvb = NULL;
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2012-08-02 22:40:02 +00:00
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guint8 dti = 0;
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2012-08-02 21:53:47 +00:00
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gboolean dissected;
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info_buffer = ep_alloc( STRLEN );
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info_buffer[0] = '\0';
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col_set_str( pinfo->cinfo, COL_PROTOCOL, "AX.25-NoL3");
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col_clear( pinfo->cinfo, COL_INFO);
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offset = 0;
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g_snprintf( info_buffer, STRLEN, "Text" );
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2012-08-02 22:40:02 +00:00
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if ( gPREF_APRS )
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{
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dti = tvb_get_guint8( tvb, offset );
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if ( isaprs( dti ) )
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g_snprintf( info_buffer, STRLEN, "APRS" );
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}
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2012-08-02 21:53:47 +00:00
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if ( gPREF_DX )
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{
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if ( tvb_get_guint8( tvb, offset ) == 'D' && tvb_get_guint8( tvb, offset + 1 ) == 'X' )
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g_snprintf( info_buffer, STRLEN, "DX cluster" );
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}
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col_add_str( pinfo->cinfo, COL_INFO, info_buffer );
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/* Call sub-dissectors here */
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if ( parent_tree )
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{
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/* create display subtree for the protocol */
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ti = proto_tree_add_protocol_format( parent_tree,
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proto_ax25_nol3,
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tvb,
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0,
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tvb_length_remaining( tvb, offset ),
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"AX.25 No Layer 3 - (%s)", info_buffer );
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ax25_nol3_tree = proto_item_add_subtree( ti, ett_ax25_nol3 );
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saved_private_data = pinfo->private_data;
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next_tvb = tvb_new_subset(tvb, offset, -1, -1);
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dissected = FALSE;
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2012-08-02 22:40:02 +00:00
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if ( gPREF_APRS )
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{
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if ( isaprs( dti ) )
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{
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dissected = TRUE;
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call_dissector( aprs_handle , next_tvb, pinfo, ax25_nol3_tree );
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}
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}
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2012-08-02 21:53:47 +00:00
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if ( gPREF_DX )
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{
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if ( tvb_get_guint8( tvb, offset ) == 'D' && tvb_get_guint8( tvb, offset + 1 ) == 'X' )
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{
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dissected = TRUE;
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dissect_dx( next_tvb, pinfo, ax25_nol3_tree );
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}
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}
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if ( ! dissected )
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call_dissector( default_handle , next_tvb, pinfo, ax25_nol3_tree );
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pinfo->private_data = saved_private_data;
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}
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}
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void
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proto_register_ax25_nol3(void)
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{
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module_t *ax25_nol3_module;
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/* Setup list of header fields */
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static hf_register_info hf[] = {
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{ &hf_text,
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2012-08-02 22:40:02 +00:00
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{ "Text", "ax25_nol3.text",
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2012-08-02 21:53:47 +00:00
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FT_STRING, BASE_NONE, NULL, 0x0,
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2012-08-02 22:04:12 +00:00
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NULL, HFILL }
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2012-08-02 21:53:47 +00:00
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},
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};
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static hf_register_info hf_dx[] = {
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{ &hf_dx_report,
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2012-08-02 22:40:02 +00:00
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{ "DX", "ax25_nol3.dx",
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2012-08-02 21:53:47 +00:00
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FT_STRING, BASE_NONE, NULL, 0x0,
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"DX cluster", HFILL }
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},
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};
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/* Setup protocol subtree array */
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static gint *ett[] = {
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&ett_ax25_nol3,
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&ett_dx,
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};
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/* Register the protocol name and description */
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2012-08-03 01:58:12 +00:00
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proto_ax25_nol3 = proto_register_protocol("AX.25 no Layer 3", "AX.25 no L3", "ax25_nol3");
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2012-08-02 21:53:47 +00:00
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/* Required function calls to register the header fields and subtrees used */
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proto_register_field_array( proto_ax25_nol3, hf, array_length(hf ) );
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proto_register_subtree_array( ett, array_length( ett ) );
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/* Register preferences module */
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ax25_nol3_module = prefs_register_protocol( proto_ax25_nol3, proto_reg_handoff_ax25_nol3);
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/* Register any preference */
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2012-08-02 22:40:02 +00:00
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prefs_register_bool_preference(ax25_nol3_module, "showaprs",
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"Decode the APRS info field",
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"Enable decoding of the payload as APRS.",
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&gPREF_APRS );
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2012-08-02 21:53:47 +00:00
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prefs_register_bool_preference(ax25_nol3_module, "showcluster",
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"Decode DX cluster info field",
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"Enable decoding of the payload as DX cluster info.",
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&gPREF_DX );
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/* Register the sub-protocol name and description */
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proto_dx = proto_register_protocol("DX cluster", "DX", "dx");
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/* Register the dissector */
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register_dissector( "dx", dissect_dx, proto_dx);
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/* Register the header fields */
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proto_register_field_array( proto_dx, hf_dx, array_length( hf_dx ) );
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/* Register the subtrees used */
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/* proto_register_subtree_array( ett_dx, array_length( ett_dx ) ); */
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}
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void
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proto_reg_handoff_ax25_nol3(void)
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{
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static gboolean inited = FALSE;
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if( !inited ) {
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2012-08-03 01:58:12 +00:00
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dissector_add_uint( "ax25.pid", AX25_P_NO_L3, create_dissector_handle( dissect_ax25_nol3, proto_ax25_nol3 ) );
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2012-08-02 21:53:47 +00:00
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/*
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*/
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2012-08-02 22:40:02 +00:00
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aprs_handle = find_dissector( "aprs" );
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2012-08-02 21:53:47 +00:00
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default_handle = find_dissector( "data" );
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inited = TRUE;
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}
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}
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