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/* packet-osmux.c
* Routines for packet dissection of OSmux voice/signalling multiplex protocol
*
*
* 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/stats_tree.h>
#include <epan/tap.h>
#include <epan/prefs.h>
#include <epan/conversation.h>
void proto_register_osmux(void);
void proto_reg_handoff_osmux(void);
/*
* FIXME: Link to OSmux docs here
*/
static const value_string osmux_ft_vals[] =
{
{0x00, "Signalling"},
{0x01, "AMR"},
{0x02, "Dummy"},
{0, NULL}
};
struct osmux_hdr {
int ft;
int ctr;
int amr_f;
int amr_q;
int seq;
int circuit_id;
int amr_cmr;
int amr_ft;
};
/* Initialize the protocol and registered fields */
static dissector_handle_t osmux_handle;
static int proto_osmux = -1;
static int osmux_tap = -1;
static int hf_osmux_ft_ctr = -1;
static int hf_osmux_ft = -1;
static int hf_osmux_ctr = -1;
static int hf_osmux_amr_f = -1;
static int hf_osmux_amr_q = -1;
static int hf_osmux_seq = -1;
static int hf_osmux_circuit_id = -1;
static int hf_osmux_amr_ft_cmr = -1;
static int hf_osmux_amr_ft = -1;
static int hf_osmux_amr_cmr = -1;
/* Initialize the subtree pointers */
static gint ett_osmux = -1;
static gint ett_osmux_ft_ctr = -1;
static gint ett_osmux_amr_ft_cmr = -1;
enum {
SUB_RSL,
SUB_AMR,
SUB_DUMMY,
SUB_MAX
};
/* Code to actually dissect the packets */
static gint
dissect_osmux(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
int offset = 0;
struct osmux_hdr *osmuxh;
proto_item *ti;
proto_tree *osmux_tree = NULL;
guint8 ft_ctr, amr_ft_cmr;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "OSmux");
col_clear(pinfo->cinfo, COL_INFO);
osmuxh = wmem_new0(wmem_packet_scope(), struct osmux_hdr);
ft_ctr = tvb_get_guint8(tvb, offset);
osmuxh->ft = ft_ctr >> 5;
osmuxh->ctr = (ft_ctr >> 2) & 0x7;
osmuxh->amr_q = !!(ft_ctr & 0x02);
osmuxh->amr_f = !!(ft_ctr & 0x01);
osmuxh->seq = tvb_get_guint8(tvb, offset+1);
osmuxh->circuit_id = tvb_get_guint8(tvb, offset+2);
amr_ft_cmr = tvb_get_guint8(tvb, offset+3);
osmuxh->amr_ft = (amr_ft_cmr & 0xf0) >> 4;
osmuxh->amr_cmr = amr_ft_cmr & 0x0f;
col_append_fstr(pinfo->cinfo, COL_INFO, "OSMux ");
ti = proto_tree_add_protocol_format(tree, proto_osmux,
tvb, offset, -1,
"OSmux type %s frame",
val_to_str(osmuxh->ft, osmux_ft_vals,
"unknown 0x%02x"));
osmux_tree = proto_item_add_subtree(ti, ett_osmux);
/* Two-byte dummy packets for firewalls */
if (ft_ctr == 0x23 && tvb_reported_length(tvb) == 2) {
col_append_fstr(pinfo->cinfo, COL_INFO, "Dummy frame");
proto_tree_add_item(osmux_tree, hf_osmux_circuit_id, tvb, offset+1, 1, ENC_BIG_ENDIAN);
return 2;
}
col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
val_to_str(osmuxh->ft, osmux_ft_vals,
"unknown 0x%02x"));
{
static const gint *ft_ctr_fields[] = {
&hf_osmux_ft,
&hf_osmux_ctr,
&hf_osmux_amr_f,
&hf_osmux_amr_q,
NULL
};
proto_tree_add_bitmask(osmux_tree, tvb, offset, hf_osmux_ft_ctr,
ett_osmux_ft_ctr, ft_ctr_fields, ENC_BIG_ENDIAN);
offset++;
}
proto_tree_add_item(osmux_tree, hf_osmux_seq, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
proto_tree_add_item(osmux_tree, hf_osmux_circuit_id, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
{
static const gint *amr_ft_cmr_fields[] = {
&hf_osmux_amr_ft,
&hf_osmux_amr_cmr,
NULL
};
proto_tree_add_bitmask(osmux_tree, tvb, offset, hf_osmux_amr_ft_cmr,
ett_osmux_amr_ft_cmr, amr_ft_cmr_fields, ENC_BIG_ENDIAN);
offset++;
}
tap_queue_packet(osmux_tap, pinfo, osmuxh);
return offset;
}
void proto_register_osmux(void)
{
static hf_register_info hf[] = {
{&hf_osmux_ft_ctr,
{"FTCTRByte", "osmux.ft_ctr",
FT_UINT8, BASE_DEC, NULL, 0x00,
"Byte with Fieldtype, Counter", HFILL}
},
{&hf_osmux_ft,
{"FieldType", "osmux.ft",
FT_UINT8, BASE_DEC, VALS(osmux_ft_vals), 0xe0,
"Type of data in packet", HFILL}
},
{&hf_osmux_ctr,
{"CTR", "osmux.ctr",
FT_UINT8, BASE_HEX, NULL, 0x1c,
"Number of AMR packets inside", HFILL}
},
{&hf_osmux_amr_q,
{"AMR f", "osmux.amr_f",
FT_UINT8, BASE_HEX, NULL, 0x02,
"AMR f parameter", HFILL}
},
{&hf_osmux_amr_f,
{"AMR q", "osmux.amr_q",
FT_UINT8, BASE_HEX, NULL, 0x01,
"AMR q parameter", HFILL}
},
{&hf_osmux_seq,
{"Seq", "osmux.seq",
FT_UINT8, BASE_HEX, NULL, 0x0,
"Sequence number", HFILL}
},
{&hf_osmux_circuit_id,
{"Circuit ID", "osmux.circuit_id",
FT_UINT8, BASE_HEX, NULL, 0x0,
"Circuit ID", HFILL}
},
{&hf_osmux_amr_ft_cmr,
{"FourthByte", "osmux.amr_ft_cmr",
FT_UINT8, BASE_DEC, NULL, 0x00,
"Byte with AMR params ft and cmr", HFILL}
},
{&hf_osmux_amr_ft,
{"AMR ft", "osmux.amr_ft",
FT_UINT8, BASE_HEX, NULL, 0xf0,
"AMR parameter ft", HFILL}
},
{&hf_osmux_amr_cmr,
{"AMR cmr", "osmux.amr_cmr",
FT_UINT8, BASE_HEX, NULL, 0x0f,
"AMR parameter cmr", HFILL}
},
};
static gint *ett[] = {
&ett_osmux,
&ett_osmux_ft_ctr,
&ett_osmux_amr_ft_cmr,
};
proto_osmux = proto_register_protocol("GSM multiplexing for AMR", "GSM OSmux", "osmux");
proto_register_field_array(proto_osmux, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void proto_reg_handoff_osmux(void)
{
static gboolean osmux_initialized = FALSE;
if (!osmux_initialized) {
osmux_handle = create_dissector_handle(dissect_osmux, proto_osmux);
dissector_add_uint("udp.port", 1984, osmux_handle);
osmux_initialized = TRUE;
}
osmux_tap = register_tap("osmux");
}
/*
* 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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