forked from osmocom/wireshark
![Michael Mann](/assets/img/avatar_default.png)
This saves many dissectors the need to find the data dissector and store a handle to it. There were also some that were finding it, but not using it. For others this was the only reason for their handoff function, so it could be eliminated. Change-Id: I5d3f951ee1daa3d30c060d21bd12bbc881a8027b Reviewed-on: https://code.wireshark.org/review/14530 Petri-Dish: Michael Mann <mmann78@netscape.net> Reviewed-by: Michael Mann <mmann78@netscape.net>
305 lines
7.5 KiB
C
305 lines
7.5 KiB
C
/* 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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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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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*
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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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* APRS:
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* http://www.aprs.org/
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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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#include "config.h"
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#include <epan/ax25_pids.h>
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#define STRLEN 80
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void proto_register_ax25_nol3(void);
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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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static dissector_handle_t aprs_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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static gboolean gPREF_APRS = FALSE;
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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 int
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dissect_dx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data _U_)
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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_reported_length_remaining( tvb, offset );
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col_set_str( pinfo->cinfo, COL_PROTOCOL, "DX" );
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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, -1,
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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, ENC_ASCII|ENC_NA );
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}
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return tvb_captured_length(tvb);
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}
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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 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 '/' :
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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 '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 '}' : 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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static int
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dissect_ax25_nol3(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data _U_ )
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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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tvbuff_t *next_tvb = NULL;
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guint8 dti = 0;
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gboolean dissected;
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info_buffer = (char *)wmem_alloc( wmem_packet_scope(), 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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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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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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/* 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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-1,
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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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next_tvb = tvb_new_subset_remaining(tvb, offset);
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dissected = FALSE;
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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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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, NULL );
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}
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}
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if ( ! dissected )
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call_data_dissector(next_tvb, pinfo, ax25_nol3_tree );
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return tvb_captured_length(tvb);
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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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#if 0 /* not used ? */
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static hf_register_info hf[] = {
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{ &hf_text,
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{ "Text", "ax25_nol3.text",
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FT_STRING, BASE_NONE, NULL, 0x0,
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NULL, HFILL }
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},
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};
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#endif
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static hf_register_info hf_dx[] = {
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{ &hf_dx_report,
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{ "DX", "ax25_nol3.dx",
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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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proto_ax25_nol3 = proto_register_protocol("AX.25 no Layer 3", "AX.25 no L3", "ax25_nol3");
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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, NULL);
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/* Register any preference */
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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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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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dissector_add_uint( "ax25.pid", AX25_P_NO_L3, create_dissector_handle( dissect_ax25_nol3, proto_ax25_nol3 ) );
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/*
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*/
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aprs_handle = find_dissector_add_dependency( "aprs", proto_ax25_nol3 );
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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