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wireshark/epan/dissectors/packet-h224.c

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/* packet-h224.c
* Routines for H.224 dissection
* Copyright 2022, Anders Broman <anders.broman@ericsson.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
RFC description H.224 in SDP: RFC4573 https://www.rfc-editor.org/rfc/rfc4573.html
H.281 - FECC protocol H.281 https://www.itu.int/rec/T-REC-H.281/en
H.224 - transport encapsulation for FECC H.224 https://www.itu.int/rec/T-REC-H.224-200501-I/en
H.323 Annex Q - packing description H.224 in RTP H.323 https://www.itu.int/rec/T-REC-H.323-202203-I
*/
#include <config.h>
#include <epan/packet.h>
#include <epan/proto.h>
//#include <epan/expert.h>
//#include <epan/prefs.h>
/* Prototypes */
void proto_reg_handoff_h224(void);
void proto_register_h224(void);
/* Initialize the protocol and registered fields */
static int proto_h224 = -1;
static int hf_h224_q922_dlci_priority = -1;
static int hf_h224_q922_ctl = -1;
static int hf_h224_dta = -1;
static int hf_h224_sta = -1;
static int hf_h224_reserved = -1;
static int hf_h224_standard_client_id = -1;
static int hf_h224_extended_client_id = -1;
static int hf_h224_country_code = -1;
static int hf_h224_manufacturer_code = -1;
static int hf_h224_client_id_manufacturer = -1;
static int hf_h224_es_b7 = -1;
static int hf_h224_bs_b6 = -1;
static int hf_h224_c1_b5 = -1;
static int hf_h224_c2_b4 = -1;
static int hf_h224_seg_b3b0 = -1;
static int hf_h224_client_data = -1;
//static expert_field ei_h224_EXPERTABBREV = EI_INIT;
static dissector_handle_t h224_handle;
/* Initialize the subtree pointers */
static gint ett_h224 = -1;
#define H224_DATA_PRI_MASK 0xFCF0
/* DLCI address for data priority */
static const value_string h224_data_priority[] =
{
{ 6, "Low Priority Data" },
{ 7, "High Priority Data" },
{ 0, NULL },
};
/* Code to actually dissect the packets */
static int
dissect_h224(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree, void* data _U_)
{
proto_item* ti;
proto_tree* h224_tree;
guint offset = 0;
guint8 oct;
/* Set the Protocol column in the summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "H.224");
ti = proto_tree_add_item(tree, proto_h224, tvb, offset, -1, ENC_NA);
h224_tree = proto_item_add_subtree(ti, ett_h224);
/* On IP transport networks, the H.224 protocol octet structure shall be the same as Figure 2/H.224
* except that the HDLC bit stuffing, HDLC flags and HDLC Frame Check Sequence shall be omitted.
*/
/* The 10-bit DLCI address for data priority */
proto_tree_add_item(h224_tree, hf_h224_q922_dlci_priority, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
/* Q.922 UI-Mode format 1 octets */
proto_tree_add_item(h224_tree, hf_h224_q922_ctl, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
/* Destination terminal address 2 octets */
proto_tree_add_item(h224_tree, hf_h224_dta, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
/* Source terminal address 2 octets */
proto_tree_add_item(h224_tree, hf_h224_sta, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(h224_tree, hf_h224_reserved, tvb, offset, 1, ENC_NA);
/*
* CLIENT ID: The client to receive the contents of the datagram. The Client ID may be any
* of the following formats:
* - Standard Client ID – Single octet.
* - Extended Client ID – Two octets (0x7E, extended Client ID).
* - Non-standard Client ID – Six octets (0x7F, country, manufacturer code, ID)
*/
oct = tvb_get_guint8(tvb, offset);
if (oct == 0x7e) {
offset++;
proto_tree_add_item(h224_tree, hf_h224_extended_client_id, tvb, offset, 1, ENC_NA);
offset++;
} else if (oct == 0x7f){
offset++;
proto_tree_add_item(h224_tree, hf_h224_country_code, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(h224_tree, hf_h224_manufacturer_code, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(h224_tree, hf_h224_client_id_manufacturer, tvb, offset, 1, ENC_NA);
offset++;
} else {
proto_tree_add_item(h224_tree, hf_h224_standard_client_id, tvb, offset, 1, ENC_NA);
offset++;
}
static int* const h224_flags[] = {
&hf_h224_es_b7,
&hf_h224_bs_b6,
&hf_h224_c1_b5,
&hf_h224_c2_b4,
&hf_h224_seg_b3b0,
NULL
};
proto_tree_add_bitmask_list(h224_tree, tvb, offset, 1, h224_flags, ENC_BIG_ENDIAN);
offset++;
/* Data */
proto_tree_add_item(h224_tree, hf_h224_client_data, tvb, offset, -1, ENC_NA);
return tvb_reported_length(tvb);
}
/* Register the protocol with Wireshark. */
void
proto_register_h224(void)
{
//module_t *h224_module;
//expert_module_t *expert_h224;
static hf_register_info hf[] = {
{ &hf_h224_q922_dlci_priority,
{ "Q.922 DLCI Priority", "h224.q922_dlci_pri",
FT_UINT16, BASE_HEX, VALS(h224_data_priority), H224_DATA_PRI_MASK,
NULL, HFILL }
},
{ &hf_h224_q922_ctl,
{ "Q.922 Control Octet", "h224.q922_ctl",
FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_h224_dta,
{ "Destination Terminal Address", "h224.dta",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_h224_sta,
{ "Source Terminal Address", "h224.sta",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_h224_reserved,
{ "Reserved", "h224.reserved",
FT_UINT8, BASE_DEC, NULL, 0x80,
NULL, HFILL }
},
{ &hf_h224_standard_client_id,
{ "Standard Client ID", "h224.standard_client_id",
FT_UINT8, BASE_HEX, NULL, 0x7f,
NULL, HFILL }
},
{ &hf_h224_extended_client_id,
{ "Extended Client ID", "h224.extended_client_id",
FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_h224_country_code,
{ "Country code", "h224.country_code",
FT_UINT16, BASE_HEX, NULL, 0xffff,
NULL, HFILL }
},
{ &hf_h224_manufacturer_code,
{ "Manufacturer code", "h224.manufacturer_code",
FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_h224_client_id_manufacturer,
{ "Manufacturer Client ID", "h224.manufacturer_client_id",
FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_h224_es_b7,
{ "Ending Segment(ES)", "h224.flag.es",
FT_BOOLEAN, 8, NULL, 0x80,
NULL, HFILL }
},
{ &hf_h224_bs_b6,
{ "Beginning Segment(BS)", "h224.flag.bs",
FT_BOOLEAN, 8, NULL, 0x40,
NULL, HFILL }
},
{ &hf_h224_c1_b5,
{ "C1", "h224.flag.c1",
FT_BOOLEAN, 8, NULL, 0x20,
NULL, HFILL }
},
{ &hf_h224_c2_b4,
{ "C0", "h224.flag.c0",
FT_BOOLEAN, 8, NULL, 0x10,
NULL, HFILL }
},
{ &hf_h224_seg_b3b0,
{ "Segment number", "h224.flags_seg",
FT_UINT8, BASE_DEC, NULL, 0x0f,
NULL, HFILL }
},
{ &hf_h224_client_data,
{ "Client data", "h224.data",
FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
};
static gint *ett[] = {
&ett_h224
};
/* Setup protocol expert items */
//static ei_register_info ei[] = {
// { &ei_h224_EXPERTABBREV,
// { "h224.EXPERTABBREV", PI_GROUP, PI_SEVERITY,
// "EXPERTDESCR", EXPFILL }
// }
//};
/* Register the protocol name and description */
proto_h224 = proto_register_protocol("H.224", "H.224", "h224");
/* Register the header fields and subtrees */
proto_register_field_array(proto_h224, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Register expert items */
// expert_h224 = expert_register_protocol(proto_h224);
// expert_register_field_array(expert_h224, ei, array_length(ei));
h224_handle = register_dissector("h224", dissect_h224, proto_h224);
}
void
proto_reg_handoff_h224(void)
{
dissector_add_string("rtp_dyn_payload_type", "H224", h224_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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