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wireshark/epan/dissectors/packet-gsm_um.c
Michael Mann 1e60d63c8c Create call_data_dissector() to call data dissector. 
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>
2016-03-20 17:38:03 +00:00

319 lines
9.2 KiB
C
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/* packet-gsm_um.c
* Routines for GSM Um packet disassembly
* Duncan Salerno <duncan.salerno@googlemail.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <wiretap/wtap.h>
void proto_register_gsm_um(void);
void proto_reg_handoff_gsm_um(void);
static int proto_gsm_um = -1;
static int hf_gsm_um_direction = -1;
static int hf_gsm_um_channel = -1;
static int hf_gsm_um_bsic = -1;
static int hf_gsm_um_arfcn = -1;
static int hf_gsm_um_band = -1;
static int hf_gsm_um_frequency = -1;
static int hf_gsm_um_frame = -1;
static int hf_gsm_um_error = -1;
static int hf_gsm_um_timeshift = -1;
static int hf_gsm_um_l2_pseudo_len = -1;
static gint ett_gsm_um = -1;
static dissector_handle_t lapdm_handle;
static dissector_handle_t dtap_handle;
static gboolean dcs1800_gsm = TRUE;
#define GSM_UM_L2_PSEUDO_LEN 0xfc
static void
decode_arfcn(guint16 arfcn, const char **band, guint *uplink, guint *downlink)
{
/* Decode ARFCN to frequency using GSM 05.05 */
if( arfcn >= 1 && arfcn <= 124 ) {
*band = "P-GSM 900";
*uplink = 890000 + 200 * arfcn;
*downlink = *uplink + 45000;
}
else if( arfcn == 0 ) {
*band = "E-GSM 900";
*uplink = 890000 + 200 * arfcn;
*downlink = *uplink + 45000;
}
else if( arfcn >= 975 && arfcn <= 1023 ) {
*band = "E-GSM 900";
*uplink = 890000 + 200 * (arfcn - 1024);
*downlink = *uplink + 45000;
}
else if( arfcn >= 955 && arfcn <= 974 ) {
*band = "R-GSM 900";
*uplink = 890000 + 200 * (arfcn - 1024);
*downlink = *uplink + 45000;
}
else if( arfcn >= 512 && arfcn <= 885 && dcs1800_gsm) {
*band = "DCS 1800";
*uplink = 1710200 + 200 * (arfcn - 512);
*downlink = *uplink + 95000;
}
else if( arfcn >= 512 && arfcn <= 810 && !dcs1800_gsm) {
*band = "PCS 1900";
*uplink = 1850200 + 200 * (arfcn - 512);
*downlink = *uplink + 80000;
}
else if( arfcn >= 259 && arfcn <= 293 ) {
*band = "GSM 450";
*uplink = 450600 + 200 * (arfcn - 259);
*downlink = *uplink + 10000;
}
else if( arfcn >= 306 && arfcn <= 340 ) {
*band = "GSM 480";
*uplink = 479000 + 200 * (arfcn - 306);
*downlink = *uplink + 10000;
}
else if( arfcn >= 128 && arfcn <= 251 ) {
*band = "GSM 850";
*uplink = 824200 + 200 * (arfcn - 128);
*downlink = *uplink + 45000;
}
else {
*band = "Unknown";
*uplink = *downlink = 0;
}
}
static int
dissect_gsm_um(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_tree *gsm_um_tree = NULL;
proto_item *ti;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "GSM Um");
if (pinfo->pseudo_header->gsm_um.uplink) {
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "BTS");
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "MS");
}
else {
switch (pinfo->pseudo_header->gsm_um.channel) {
case GSM_UM_CHANNEL_BCCH:
case GSM_UM_CHANNEL_CCCH:
case GSM_UM_CHANNEL_PCH:
case GSM_UM_CHANNEL_AGCH:
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "Broadcast");
break;
default:
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "MS");
break;
}
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "BTS");
}
if (tree) {
const char *channel;
ti = proto_tree_add_item(tree, proto_gsm_um, tvb, 0, 0, ENC_NA);
gsm_um_tree = proto_item_add_subtree(ti, ett_gsm_um);
switch( pinfo->pseudo_header->gsm_um.channel ) {
case GSM_UM_CHANNEL_BCCH: channel = "BCCH"; break;
case GSM_UM_CHANNEL_CCCH: channel = "CCCH"; break;
case GSM_UM_CHANNEL_PCH: channel = "PCH"; break;
case GSM_UM_CHANNEL_AGCH: channel = "AGCH"; break;
case GSM_UM_CHANNEL_SACCH: channel = "SACCH"; break;
case GSM_UM_CHANNEL_FACCH: channel = "FACCH"; break;
case GSM_UM_CHANNEL_SDCCH: channel = "SDCCH"; break;
default: channel = "Unknown"; break;
}
if( pinfo->pseudo_header->gsm_um.uplink ) {
proto_tree_add_string(gsm_um_tree, hf_gsm_um_direction, tvb, 0, 0, "Uplink");
}
else {
proto_tree_add_string(gsm_um_tree, hf_gsm_um_direction, tvb, 0, 0, "Downlink");
}
proto_tree_add_string(gsm_um_tree, hf_gsm_um_channel, tvb, 0, 0, channel);
/* Show the other fields, if we have them (ie. downlink, BTS->MS) */
if( !pinfo->pseudo_header->gsm_um.uplink ) {
const char *band;
guint downlink, uplink;
decode_arfcn(pinfo->pseudo_header->gsm_um.arfcn, &band, &uplink, &downlink);
proto_tree_add_uint(gsm_um_tree, hf_gsm_um_arfcn, tvb, 0, 0,
pinfo->pseudo_header->gsm_um.arfcn);
proto_tree_add_string(gsm_um_tree, hf_gsm_um_band, tvb, 0, 0,
band);
proto_tree_add_uint_format_value(gsm_um_tree, hf_gsm_um_frequency, tvb, 0, 0,
downlink, "%u.%03uMHz", downlink / 1000, downlink % 1000);
proto_tree_add_uint(gsm_um_tree, hf_gsm_um_bsic, tvb, 0, 0,
pinfo->pseudo_header->gsm_um.bsic);
proto_tree_add_uint(gsm_um_tree, hf_gsm_um_frame, tvb, 0, 0,
pinfo->pseudo_header->gsm_um.tdma_frame);
proto_tree_add_uint(gsm_um_tree, hf_gsm_um_error, tvb, 0, 0,
pinfo->pseudo_header->gsm_um.error);
proto_tree_add_uint(gsm_um_tree, hf_gsm_um_timeshift, tvb, 0, 0,
pinfo->pseudo_header->gsm_um.timeshift);
}
}
/* TODO: If CCCH downlink could work out of PCH or AGCH by peeking at next bytes, uplink is RACH */
switch( pinfo->pseudo_header->gsm_um.channel ) {
case GSM_UM_CHANNEL_BCCH:
case GSM_UM_CHANNEL_CCCH:
case GSM_UM_CHANNEL_PCH:
case GSM_UM_CHANNEL_AGCH:
if( !pinfo->pseudo_header->gsm_um.uplink ) {
tvbuff_t *next_tvb;
guint8 pseudo_len, len_left, len_byte;
len_left = tvb_reported_length(tvb);
len_byte = tvb_get_guint8(tvb, 0);
pseudo_len = len_byte >> 2;
next_tvb = tvb_new_subset(tvb, 1, MIN(len_left, pseudo_len), -1);
if (tree) {
proto_tree_add_uint(gsm_um_tree, hf_gsm_um_l2_pseudo_len, tvb, 0, 1,
len_byte);
}
/* Only dissect non-empty frames */
if( tvb_reported_length(next_tvb) ) {
call_dissector(dtap_handle, next_tvb, pinfo, tree);
}
}
else {
/* Either RACH, or something invalid */
call_data_dissector(tvb, pinfo, tree);
}
break;
case GSM_UM_CHANNEL_SACCH:
case GSM_UM_CHANNEL_FACCH:
case GSM_UM_CHANNEL_SDCCH:
call_dissector(lapdm_handle, tvb, pinfo, tree);
break;
default:
call_data_dissector(tvb, pinfo, tree);
break;
}
return tvb_captured_length(tvb);
}
void
proto_register_gsm_um(void)
{
static hf_register_info hf[] = {
{ &hf_gsm_um_direction,
{ "Direction", "gsm_um.direction", FT_STRINGZ, BASE_NONE,
NULL, 0x0, NULL, HFILL }},
{ &hf_gsm_um_channel,
{ "Channel", "gsm_um.channel", FT_STRINGZ, BASE_NONE,
NULL, 0x0, NULL, HFILL }},
{ &hf_gsm_um_bsic,
{ "BSIC", "gsm_um.bsic", FT_UINT8, BASE_DEC,
NULL, 0x0, "Base station identity code", HFILL }},
{ &hf_gsm_um_arfcn,
{ "ARFCN", "gsm_um.arfcn", FT_UINT16, BASE_DEC,
NULL, 0x0, "Absolute radio frequency channel number", HFILL }},
{ &hf_gsm_um_band,
{ "Band", "gsm_um.band", FT_STRING, BASE_NONE,
NULL, 0x0, NULL, HFILL }},
{ &hf_gsm_um_frequency,
{ "Frequency", "gsm_um.frequency", FT_UINT32, BASE_DEC,
NULL, 0x0, NULL, HFILL }},
{ &hf_gsm_um_frame,
{ "TDMA Frame", "gsm_um.frame", FT_UINT32, BASE_DEC,
NULL, 0x0, NULL, HFILL }},
{ &hf_gsm_um_error,
{ "Error", "gsm_um.error", FT_UINT8, BASE_DEC,
NULL, 0x0, NULL, HFILL }},
{ &hf_gsm_um_timeshift,
{ "Timeshift", "gsm_um.timeshift", FT_UINT16, BASE_DEC,
NULL, 0x0, NULL, HFILL }},
{ &hf_gsm_um_l2_pseudo_len,
{ "L2 Pseudo Length", "gsm_um.l2_pseudo_len", FT_UINT8, BASE_DEC,
NULL, GSM_UM_L2_PSEUDO_LEN, NULL, HFILL }}
};
static gint *ett[] = {
&ett_gsm_um
};
module_t *gsm_um_module;
proto_gsm_um = proto_register_protocol("GSM Um Interface", "GSM Um", "gsm_um");
proto_register_field_array(proto_gsm_um, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
gsm_um_module = prefs_register_protocol(proto_gsm_um, NULL);
prefs_register_bool_preference(gsm_um_module, "dcs1800",
"Treat ARFCN 512-810 as DCS 1800 rather than PCS 1900",
"Treat ARFCN 512-810 as DCS 1800 rather than PCS 1900",
&dcs1800_gsm);
}
void
proto_reg_handoff_gsm_um(void)
{
dissector_handle_t gsm_um_handle;
lapdm_handle = find_dissector_add_dependency("lapdm", proto_gsm_um);
dtap_handle = find_dissector_add_dependency("gsm_a_dtap", proto_gsm_um);
gsm_um_handle = create_dissector_handle(dissect_gsm_um, proto_gsm_um);
dissector_add_uint("wtap_encap", WTAP_ENCAP_GSM_UM, gsm_um_handle);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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