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/* packet-rmt-fec.c
* Reliable Multicast Transport (RMT)
* FEC Building Block dissector
* Copyright 2005, Stefano Pettini <spettini@users.sourceforge.net>
*
* Forward Error Correction (ALC):
* -------------------------------
*
* The goal of the FEC building block is to describe functionality
* directly related to FEC codes that is common to all reliable content
* delivery IP multicast protocols, and to leave out any additional
* functionality that is specific to particular protocols.
*
* References:
* RFC 3452, Forward Error Correction Building Block
* RFC 3695, Compact Forward Error Correction (FEC) Schemes
* Simple XOR, Reed-Solomon, and Parity Check Matrix-based FEC Schemes draft-peltotalo-rmt-bb-fec-supp-xor-pcm-rs-00
* IANA RMT FEC parameters (http://www.iana.org/assignments/rmt-fec-parameters)
*
* $Id$
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdlib.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/prefs.h>
#include "packet-rmt-fec.h"
/* String tables */
const value_string string_fec_encoding_id[] =
{
{ 0, "Compact No-Code" },
{ 2, "Simple XOR, Reed-Solomon, and Parity Check Matrix-based FEC Codes" },
{ 128, "Small Block, Large Block and Expandable FEC Codes" },
{ 129, "Small Block Systematic FEC Codes" },
{ 130, "Compact FEC Codes" },
{ 132, "Simple XOR, Reed-Solomon, and Parity Check Matrix-based FEC Codes" },
{ 0, NULL }
};
/* FEC exported functions */
/* ====================== */
/* Info */
/* ---- */
void fec_info_column(struct _fec *fec, packet_info *pinfo)
{
if (fec->sbn_present)
col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "SBN: %u", fec->sbn);
if (fec->esi_present)
col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "ESI: 0x%X", fec->esi);
}
/* Dissection */
/* ---------- */
/* Decode an EXT_FTI extension and fill FEC array */
void fec_decode_ext_fti(struct _ext *e, tvbuff_t *tvb, proto_tree *tree, gint ett, struct _fec_ptr f)
{
proto_item* ti = NULL;
proto_tree *ext_tree;
if (tree)
ti = proto_tree_add_none_format(tree, f.hf->fti_header, tvb, e->offset, e->length,
"EXT_FTI, FEC Object Transmission Information (%u)", e->het);
if (f.fec->encoding_id_present)
{
ext_tree = proto_item_add_subtree(ti, ett);
rmt_ext_decode_default_header(e, tvb, ext_tree);
/* Decode 48-bit length field */
f.fec->transfer_length = tvb_get_ntoh64(tvb, e->offset) & G_GINT64_CONSTANT(0xFFFFFFFFFFFFU);
if (f.fec->encoding_id >= 128)
{
/* Decode FEC Instance ID */
f.fec->instance_id_present = TRUE;
f.fec->instance_id = (guint8) tvb_get_ntohs(tvb, e->offset+8);
}
if (tree)
proto_tree_add_uint64(ext_tree, f.hf->fti_transfer_length, tvb, e->offset+2, 6, f.fec->transfer_length);
switch (f.fec->encoding_id)
{
case 0:
case 2:
case 128:
case 130:
f.fec->encoding_symbol_length = tvb_get_ntohs(tvb, e->offset+10);
f.fec->max_source_block_length = tvb_get_ntohl(tvb, e->offset+12);
if (tree)
{
proto_tree_add_uint(ext_tree, f.hf->fti_encoding_symbol_length, tvb, e->offset+10, 2, f.fec->encoding_symbol_length);
proto_tree_add_uint(ext_tree, f.hf->fti_max_source_block_length, tvb, e->offset+12, 4, f.fec->max_source_block_length);
}
break;
case 129:
f.fec->encoding_symbol_length = tvb_get_ntohs(tvb, e->offset+10);
f.fec->max_source_block_length = tvb_get_ntohs(tvb, e->offset+12);
f.fec->max_number_encoding_symbols = tvb_get_ntohs(tvb, e->offset+14);
if (tree)
{
proto_tree_add_uint(ext_tree, f.hf->fti_encoding_symbol_length, tvb, e->offset+10, 2, f.fec->encoding_symbol_length);
proto_tree_add_uint(ext_tree, f.hf->fti_max_source_block_length, tvb, e->offset+12, 2, f.fec->max_source_block_length);
proto_tree_add_uint(ext_tree, f.hf->fti_max_number_encoding_symbols, tvb, e->offset+14, 2, f.fec->max_number_encoding_symbols);
}
break;
case 132:
f.fec->encoding_symbol_length = tvb_get_ntohs(tvb, e->offset+10);
f.fec->max_source_block_length = tvb_get_ntohl(tvb, e->offset+12);
f.fec->max_number_encoding_symbols = tvb_get_ntohl(tvb, e->offset+16);
if (tree)
{
proto_tree_add_uint(ext_tree, f.hf->fti_encoding_symbol_length, tvb, e->offset+10, 2, f.fec->encoding_symbol_length);
proto_tree_add_uint(ext_tree, f.hf->fti_max_source_block_length, tvb, e->offset+12, 4, f.fec->max_source_block_length);
proto_tree_add_uint(ext_tree, f.hf->fti_max_number_encoding_symbols, tvb, e->offset+16, 4, f.fec->max_number_encoding_symbols);
}
break;
}
} else
if (tree)
rmt_ext_decode_default_subtree(e, tvb, ti, ett);
}
/* Dissect a FEC header:
* fec - ptr to the logical FEC packet representation to fill
* hf - ptr to header fields array
* ett - ptr to ett array
* prefs - ptr to FEC prefs array
* tvb - buffer
* pinfo - packet info
* tree - tree where to add FEC header subtree
* offset - ptr to offset to use and update
*/
void fec_dissector(struct _fec_ptr f, tvbuff_t *tvb, proto_tree *tree, guint *offset)
{
proto_item *ti;
proto_tree *fec_tree;
guint offset_save = *offset;
/* Create the FEC subtree */
if (tree)
{
ti = proto_tree_add_item(tree, f.hf->header, tvb, *offset, -1, FALSE);
fec_tree = proto_item_add_subtree(ti, f.ett->main);
} else
{
ti = NULL;
fec_tree = NULL;
}
/* FEC Encoding ID and FEC Instance ID processing */
if (f.fec->encoding_id_present)
{
if (tree)
{
proto_tree_add_uint(fec_tree, f.hf->encoding_id, tvb, *offset, 0, f.fec->encoding_id);
if (f.fec->encoding_id >= 128 && f.fec->instance_id_present)
proto_tree_add_uint(fec_tree, f.hf->instance_id, tvb, *offset, 0, f.fec->instance_id);
}
switch (f.fec->encoding_id)
{
case 0:
case 130:
f.fec->sbn = tvb_get_ntohs(tvb, *offset);
f.fec->esi = tvb_get_ntohs(tvb, *offset+2);
if (tree)
{
proto_tree_add_uint(fec_tree, f.hf->sbn, tvb, *offset, 2, f.fec->sbn);
proto_tree_add_uint(fec_tree, f.hf->esi, tvb, *offset+2, 2, f.fec->esi);
}
f.fec->sbn_present = TRUE;
f.fec->esi_present = TRUE;
*offset += 4;
break;
case 2:
case 128:
case 132:
f.fec->sbn = tvb_get_ntohl(tvb, *offset);
f.fec->esi = tvb_get_ntohl(tvb, *offset+4);
if (tree)
{
proto_tree_add_uint(fec_tree, f.hf->sbn, tvb, *offset, 4, f.fec->sbn);
proto_tree_add_uint(fec_tree, f.hf->esi, tvb, *offset+4, 4, f.fec->esi);
}
f.fec->sbn_present = TRUE;
f.fec->esi_present = TRUE;
*offset += 8;
break;
case 129:
f.fec->sbn = tvb_get_ntohl(tvb, *offset);
f.fec->sbl = tvb_get_ntohs(tvb, *offset+4);
f.fec->esi = tvb_get_ntohs(tvb, *offset+6);
if (tree)
{
proto_tree_add_uint(fec_tree, f.hf->sbn, tvb, *offset, 4, f.fec->sbn);
proto_tree_add_uint(fec_tree, f.hf->sbl, tvb, *offset+4, 2, f.fec->sbl);
proto_tree_add_uint(fec_tree, f.hf->esi, tvb, *offset+6, 2, f.fec->esi);
}
f.fec->sbn_present = TRUE;
f.fec->sbl_present = TRUE;
f.fec->esi_present = TRUE;
*offset += 8;
break;
}
}
if (tree)
proto_item_set_len(ti, *offset - offset_save);
}
void fec_dissector_free(struct _fec *fec _U_)
{
}
/* Preferences */
/* ----------- */
/* Set/Reset preferences to default values */
void fec_prefs_set_default(struct _fec_prefs *fec_prefs _U_)
{
}
/* Register preferences */
void fec_prefs_register(struct _fec_prefs *fec_prefs _U_, module_t *module _U_)
{
}
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