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/* packet-2dparityfec.c
* Mark Lewis <mlewis@altera.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
** RTP Payload dissector for packets as specified in:
** Pro-MPEG Code of Practice #3 release 2
**
** This protocol defines a format for FEC data embedded within RTP packets with
** a payload type of 96 (0x60). The format of the FEC packets, which reside within
** the RTP payload, is as follows...
**
** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** | SNBase low bits | Length Recovery |
** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** |E| PT recovery | Mask |
** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** | TS recovery |
** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** |X|D|type |index| Offset | NA |SNBase ext bits|
** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** | |
** : FEC Payload :
** | |
** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
**
** For more information on this protocol see...
** http://www.pro-mpeg.org/publications/pdf/Vid-on-IP-CoP3-r2.pdf
**
**
** Notes:
**
** This protocol always resides in RTP packets with payload type 96. However,
** type 96 is dynamic and may refer to other protocols. As Pro-MPEG FEC must
** function in the absence of a control channel, and because this data is
** likely to be transmitted within closed networks, no automatic mechanism
** exists for specifying the existence of Pro-MPEG FEC on payload type 96.
** This dissector is thus disabled by default. Dissection of this protocol
** may be enabled from the 2dparityfec panel under Preferences->Protocols.
**
** Mark Lewis - 20th June 2006
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
/* forward reference */
void proto_register_2dparityfec(void);
void proto_reg_handoff_2dparityfec(void);
static dissector_handle_t handle_2dparityfec = NULL;
static gboolean dissect_fec = FALSE;
static int fec_rtp_payload_type = 96;
static int proto_2dparityfec = -1;
static int hf_2dparityfec_index = -1;
static int hf_2dparityfec_length_recovery = -1;
static int hf_2dparityfec_mask = -1;
static int hf_2dparityfec_na = -1;
static int hf_2dparityfec_offset = -1;
static int hf_2dparityfec_payload = -1;
static int hf_2dparityfec_pt_recovery = -1;
static int hf_2dparityfec_rfc2733_ext = -1;
static int hf_2dparityfec_row_flag = -1;
static int hf_2dparityfec_snbase_ext = -1;
static int hf_2dparityfec_snbase_low = -1;
static int hf_2dparityfec_ts_pro_mpeg_ext = -1;
static int hf_2dparityfec_ts_recovery = -1;
static int hf_2dparityfec_type = -1;
static gint ett_2dparityfec = -1;
static const value_string fec_type_names[] = {
{0, "XOR"},
{1, "Hamming"},
{2, "Reed-Solomon"},
{0, NULL}
};
static int dissect_2dparityfec(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
guint8 OffsetField;
guint8 NAField;
guint32 SNBase;
guint8 D;
/* Extract SNBase */
SNBase = (guint32)tvb_get_guint8(tvb, 0)<<8;
SNBase |= (guint32)tvb_get_guint8(tvb, 1);
SNBase |= (guint32)tvb_get_guint8(tvb, 15)<<16;
/* Extract D */
D = (tvb_get_guint8(tvb, 12)>>6) & 0x1;
/* Extract Offset and NA */
OffsetField = tvb_get_guint8(tvb, 13);
NAField = tvb_get_guint8(tvb, 14);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "2dFEC");
/* Configure the info column */
if(D)
{
col_add_fstr(pinfo->cinfo, COL_INFO, "Row FEC - SNBase=%u, Offset=%u, NA=%u",
SNBase, OffsetField, NAField);
}
else
{
col_add_fstr(pinfo->cinfo, COL_INFO, "Column FEC - SNBase=%u, Offset=%u, NA=%u",
SNBase, OffsetField, NAField);
}
if(tree)
{
/* we are being asked for details */
proto_item *ti;
proto_tree *tree_2dparityfec;
gint offset = 0;
ti = proto_tree_add_item(tree, proto_2dparityfec, tvb, 0, -1, ENC_NA);
tree_2dparityfec = proto_item_add_subtree(ti, ett_2dparityfec);
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_snbase_low, tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_length_recovery, tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_rfc2733_ext, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_pt_recovery, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_mask, tvb, offset, 3, ENC_BIG_ENDIAN); offset += 3;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_ts_recovery, tvb, offset, 4, ENC_BIG_ENDIAN); offset += 4;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_ts_pro_mpeg_ext, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_row_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_type, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_index, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_offset, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_na, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_snbase_ext, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1;
proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_payload, tvb, offset, -1, ENC_NA);
}
return tvb_captured_length(tvb);
}
void proto_register_2dparityfec(void)
{
static hf_register_info hf[] = {
{ &hf_2dparityfec_snbase_low,
{ "SNBase low", "2dparityfec.snbase_low",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_2dparityfec_length_recovery,
{ "Length recovery", "2dparityfec.lr",
FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_2dparityfec_rfc2733_ext,
{ "RFC2733 Extension (E)", "2dparityfec.e",
FT_BOOLEAN, 8, NULL, 0x80,
NULL, HFILL }
},
{ &hf_2dparityfec_pt_recovery,
{ "Payload Type recovery", "2dparityfec.ptr",
FT_UINT8, BASE_HEX, NULL, 0x7f,
NULL, HFILL }
},
{ &hf_2dparityfec_mask,
{ "Mask", "2dparityfec.mask",
/*FT_UINT32*/FT_UINT24, BASE_HEX, NULL, /*0x00ffffff*/0x0,
NULL, HFILL }
},
{ &hf_2dparityfec_ts_recovery,
{ "Timestamp recovery", "2dparityfec.tsr",
FT_UINT32, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_2dparityfec_ts_pro_mpeg_ext,
{ "Pro-MPEG Extension (X)", "2dparityfec.x",
FT_BOOLEAN, 8, NULL, 0x80,
NULL, HFILL }
},
{ &hf_2dparityfec_row_flag,
{ "Row FEC (D)", "2dparityfec.d",
FT_BOOLEAN, 8, NULL, 0x40,
NULL, HFILL }
},
{ &hf_2dparityfec_type,
{ "Type", "2dparityfec.type",
FT_UINT8, BASE_DEC, VALS(fec_type_names), 0x38,
NULL, HFILL }
},
{ &hf_2dparityfec_index,
{ "Index", "2dparityfec.index",
FT_UINT8, BASE_DEC, NULL, 0x07,
NULL, HFILL }
},
{ &hf_2dparityfec_offset,
{ "Offset", "2dparityfec.offset",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_2dparityfec_na,
{ "NA", "2dparityfec.na",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_2dparityfec_snbase_ext,
{ "SNBase ext", "2dparityfec.snbase_ext",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_2dparityfec_payload,
{ "FEC Payload", "2dparityfec.payload",
FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_2dparityfec,
};
module_t *module_2dparityfec;
proto_2dparityfec = proto_register_protocol("Pro-MPEG Code of Practice #3 release 2 FEC Protocol", "2dparityfec", "2dparityfec");
proto_register_field_array(proto_2dparityfec, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
module_2dparityfec = prefs_register_protocol(proto_2dparityfec,
proto_reg_handoff_2dparityfec);
prefs_register_bool_preference(module_2dparityfec, "enable",
"Decode Pro-MPEG FEC on RTP dynamic payload type 96",
"Enable this option to recognise all traffic on RTP dynamic payload type 96 (0x60) "
"as FEC data corresponding to Pro-MPEG Code of Practice #3 release 2",
&dissect_fec);
handle_2dparityfec = register_dissector("2dparityfec", dissect_2dparityfec,
proto_2dparityfec);
}
void proto_reg_handoff_2dparityfec(void)
{
if (dissect_fec) {
dissector_add_uint("rtp.pt", fec_rtp_payload_type, handle_2dparityfec);
} else {
dissector_delete_uint("rtp.pt", fec_rtp_payload_type, handle_2dparityfec);
}
}
/*
* Editor modelines
*
* Local Variables:
* c-basic-offset: 3
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* ex: set shiftwidth=3 tabstop=8 expandtab:
* :indentSize=3:tabSize=8:noTabs=true:
*/
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