055dd62063
svn path=/trunk/; revision=32410
275 lines
8 KiB
C
275 lines
8 KiB
C
/* packet-rmt-fec.c
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* Reliable Multicast Transport (RMT)
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* FEC Building Block dissector
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* Copyright 2005, Stefano Pettini <spettini@users.sourceforge.net>
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*
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* Forward Error Correction (ALC):
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* -------------------------------
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*
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* The goal of the FEC building block is to describe functionality
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* directly related to FEC codes that is common to all reliable content
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* delivery IP multicast protocols, and to leave out any additional
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* functionality that is specific to particular protocols.
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*
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* References:
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* RFC 3452, Forward Error Correction Building Block
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* RFC 3695, Compact Forward Error Correction (FEC) Schemes
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* Simple XOR, Reed-Solomon, and Parity Check Matrix-based FEC Schemes draft-peltotalo-rmt-bb-fec-supp-xor-pcm-rs-00
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* IANA RMT FEC parameters (http://www.iana.org/assignments/rmt-fec-parameters)
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdlib.h>
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#include "packet-rmt-fec.h"
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/* String tables */
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const value_string string_fec_encoding_id[] =
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{
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{ 0, "Compact No-Code" },
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{ 2, "Simple XOR, Reed-Solomon, and Parity Check Matrix-based FEC Codes" },
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{ 128, "Small Block, Large Block and Expandable FEC Codes" },
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{ 129, "Small Block Systematic FEC Codes" },
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{ 130, "Compact FEC Codes" },
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{ 132, "Simple XOR, Reed-Solomon, and Parity Check Matrix-based FEC Codes" },
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{ 0, NULL }
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};
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/* FEC exported functions */
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/* ====================== */
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/* Info */
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/* ---- */
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void fec_info_column(struct _fec *fec, packet_info *pinfo)
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{
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if (fec->sbn_present)
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col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "SBN: %u", fec->sbn);
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if (fec->esi_present)
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col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "ESI: 0x%X", fec->esi);
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}
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/* Dissection */
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/* ---------- */
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/* Decode an EXT_FTI extension and fill FEC array */
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void fec_decode_ext_fti(struct _ext *e, tvbuff_t *tvb, proto_tree *tree, gint ett, struct _fec_ptr f)
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{
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proto_item* ti = NULL;
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proto_tree *ext_tree;
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if (tree)
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ti = proto_tree_add_none_format(tree, f.hf->fti_header, tvb, e->offset, e->length,
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"EXT_FTI, FEC Object Transmission Information (%u)", e->het);
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if (f.fec->encoding_id_present)
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{
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ext_tree = proto_item_add_subtree(ti, ett);
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rmt_ext_decode_default_header(e, tvb, ext_tree);
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/* Decode 48-bit length field */
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f.fec->transfer_length = tvb_get_ntoh64(tvb, e->offset) & G_GINT64_CONSTANT(0xFFFFFFFFFFFFU);
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if (f.fec->encoding_id >= 128)
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{
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/* Decode FEC Instance ID */
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f.fec->instance_id_present = TRUE;
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f.fec->instance_id = (guint8) tvb_get_ntohs(tvb, e->offset+8);
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}
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if (tree)
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proto_tree_add_uint64(ext_tree, f.hf->fti_transfer_length, tvb, e->offset+2, 6, f.fec->transfer_length);
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switch (f.fec->encoding_id)
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{
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case 0:
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case 2:
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case 128:
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case 130:
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f.fec->encoding_symbol_length = tvb_get_ntohs(tvb, e->offset+10);
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f.fec->max_source_block_length = tvb_get_ntohl(tvb, e->offset+12);
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if (tree)
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{
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proto_tree_add_uint(ext_tree, f.hf->fti_encoding_symbol_length, tvb, e->offset+10, 2, f.fec->encoding_symbol_length);
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proto_tree_add_uint(ext_tree, f.hf->fti_max_source_block_length, tvb, e->offset+12, 4, f.fec->max_source_block_length);
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}
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break;
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case 129:
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f.fec->encoding_symbol_length = tvb_get_ntohs(tvb, e->offset+10);
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f.fec->max_source_block_length = tvb_get_ntohs(tvb, e->offset+12);
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f.fec->max_number_encoding_symbols = tvb_get_ntohs(tvb, e->offset+14);
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if (tree)
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{
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proto_tree_add_uint(ext_tree, f.hf->fti_encoding_symbol_length, tvb, e->offset+10, 2, f.fec->encoding_symbol_length);
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proto_tree_add_uint(ext_tree, f.hf->fti_max_source_block_length, tvb, e->offset+12, 2, f.fec->max_source_block_length);
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proto_tree_add_uint(ext_tree, f.hf->fti_max_number_encoding_symbols, tvb, e->offset+14, 2, f.fec->max_number_encoding_symbols);
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}
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break;
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case 132:
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f.fec->encoding_symbol_length = tvb_get_ntohs(tvb, e->offset+10);
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f.fec->max_source_block_length = tvb_get_ntohl(tvb, e->offset+12);
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f.fec->max_number_encoding_symbols = tvb_get_ntohl(tvb, e->offset+16);
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if (tree)
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{
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proto_tree_add_uint(ext_tree, f.hf->fti_encoding_symbol_length, tvb, e->offset+10, 2, f.fec->encoding_symbol_length);
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proto_tree_add_uint(ext_tree, f.hf->fti_max_source_block_length, tvb, e->offset+12, 4, f.fec->max_source_block_length);
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proto_tree_add_uint(ext_tree, f.hf->fti_max_number_encoding_symbols, tvb, e->offset+16, 4, f.fec->max_number_encoding_symbols);
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}
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break;
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}
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} else
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if (tree)
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rmt_ext_decode_default_subtree(e, tvb, ti, ett);
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}
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/* Dissect a FEC header:
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* fec - ptr to the logical FEC packet representation to fill
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* hf - ptr to header fields array
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* ett - ptr to ett array
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* prefs - ptr to FEC prefs array
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* tvb - buffer
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* pinfo - packet info
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* tree - tree where to add FEC header subtree
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* offset - ptr to offset to use and update
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*/
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void fec_dissector(struct _fec_ptr f, tvbuff_t *tvb, proto_tree *tree, guint *offset)
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{
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proto_item *ti;
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proto_tree *fec_tree;
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guint offset_save = *offset;
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/* Create the FEC subtree */
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if (tree)
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{
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ti = proto_tree_add_item(tree, f.hf->header, tvb, *offset, -1, FALSE);
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fec_tree = proto_item_add_subtree(ti, f.ett->main);
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} else
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{
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ti = NULL;
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fec_tree = NULL;
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}
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/* FEC Encoding ID and FEC Instance ID processing */
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if (f.fec->encoding_id_present)
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{
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if (tree)
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{
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proto_tree_add_uint(fec_tree, f.hf->encoding_id, tvb, *offset, 0, f.fec->encoding_id);
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if (f.fec->encoding_id >= 128 && f.fec->instance_id_present)
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proto_tree_add_uint(fec_tree, f.hf->instance_id, tvb, *offset, 0, f.fec->instance_id);
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}
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switch (f.fec->encoding_id)
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{
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case 0:
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case 130:
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f.fec->sbn = tvb_get_ntohs(tvb, *offset);
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f.fec->esi = tvb_get_ntohs(tvb, *offset+2);
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if (tree)
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{
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proto_tree_add_uint(fec_tree, f.hf->sbn, tvb, *offset, 2, f.fec->sbn);
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proto_tree_add_uint(fec_tree, f.hf->esi, tvb, *offset+2, 2, f.fec->esi);
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}
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f.fec->sbn_present = TRUE;
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f.fec->esi_present = TRUE;
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*offset += 4;
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break;
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case 2:
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case 128:
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case 132:
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f.fec->sbn = tvb_get_ntohl(tvb, *offset);
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f.fec->esi = tvb_get_ntohl(tvb, *offset+4);
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if (tree)
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{
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proto_tree_add_uint(fec_tree, f.hf->sbn, tvb, *offset, 4, f.fec->sbn);
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proto_tree_add_uint(fec_tree, f.hf->esi, tvb, *offset+4, 4, f.fec->esi);
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}
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f.fec->sbn_present = TRUE;
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f.fec->esi_present = TRUE;
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*offset += 8;
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break;
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case 129:
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f.fec->sbn = tvb_get_ntohl(tvb, *offset);
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f.fec->sbl = tvb_get_ntohs(tvb, *offset+4);
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f.fec->esi = tvb_get_ntohs(tvb, *offset+6);
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if (tree)
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{
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proto_tree_add_uint(fec_tree, f.hf->sbn, tvb, *offset, 4, f.fec->sbn);
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proto_tree_add_uint(fec_tree, f.hf->sbl, tvb, *offset+4, 2, f.fec->sbl);
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proto_tree_add_uint(fec_tree, f.hf->esi, tvb, *offset+6, 2, f.fec->esi);
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}
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f.fec->sbn_present = TRUE;
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f.fec->sbl_present = TRUE;
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f.fec->esi_present = TRUE;
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*offset += 8;
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break;
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}
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}
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if (tree)
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proto_item_set_len(ti, *offset - offset_save);
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}
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void fec_dissector_free(struct _fec *fec _U_)
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{
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}
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/* Preferences */
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/* ----------- */
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/* Set/Reset preferences to default values */
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void fec_prefs_set_default(struct _fec_prefs *fec_prefs _U_)
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{
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}
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/* Register preferences */
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void fec_prefs_register(struct _fec_prefs *fec_prefs _U_, module_t *module _U_)
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{
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}
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