forked from osmocom/wireshark
264 lines
6.0 KiB
C
264 lines
6.0 KiB
C
/* packet-h261.c
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*
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* Routines for ITU-T Recommendation H.261 dissection
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*
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* $Id: packet-h261.c,v 1.8 2001/06/18 02:17:46 guy Exp $
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*
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* Copyright 2000, Philips Electronics N.V.
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* Andreas Sikkema <andreas.sikkema@philips.com>
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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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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/*
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* This dissector tries to dissect the H.261 protocol according to Annex C
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* of ITU-T Recommendation H.225.0 (02/98)
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*
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* This dissector is called by the RTP dissector
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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 <glib.h>
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#include "packet.h"
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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.h>
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#endif
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#include <stdio.h>
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#include <string.h>
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/* H.261 header fields */
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static int proto_h261 = -1;
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static int hf_h261_sbit = -1;
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static int hf_h261_ebit = -1;
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static int hf_h261_ibit = -1;
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static int hf_h261_vbit = -1;
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static int hf_h261_gobn = -1;
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static int hf_h261_mbap = -1;
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static int hf_h261_quant = -1;
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static int hf_h261_hmvd = -1; /* Mislabeled in a figure in section C.3.1 as HMDV */
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static int hf_h261_vmvd = -1;
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static int hf_h261_data = -1;
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/* H.261 fields defining a sub tree */
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static gint ett_h261 = -1;
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static void
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dissect_h261( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
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{
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proto_item *ti = NULL;
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proto_tree *h261_tree = NULL;
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unsigned int offset = 0;
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if ( check_col( pinfo->fd, COL_PROTOCOL ) ) {
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col_set_str( pinfo->fd, COL_PROTOCOL, "H.261" );
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}
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if ( check_col( pinfo->fd, COL_INFO) ) {
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col_set_str( pinfo->fd, COL_INFO, "H.261 message");
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}
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if ( tree ) {
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ti = proto_tree_add_item( tree, proto_h261, tvb, offset, tvb_length( tvb ), FALSE );
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h261_tree = proto_item_add_subtree( ti, ett_h261 );
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/* SBIT 1st octet, 3 bits */
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proto_tree_add_uint( h261_tree, hf_h261_sbit, tvb, offset, 1, tvb_get_guint8( tvb, offset ) >> 5 );
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/* EBIT 1st octet, 3 bits */
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proto_tree_add_item( h261_tree, hf_h261_ebit, tvb, offset, 1, ( tvb_get_guint8( tvb, offset ) << 3 ) >> 5 );
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/* I flag, 1 bit */
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proto_tree_add_boolean( h261_tree, hf_h261_ibit, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 2 );
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/* V flag, 1 bit */
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proto_tree_add_boolean( h261_tree, hf_h261_vbit, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 1 );
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offset++;
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/* GOBN 2nd octet, 4 bits */
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proto_tree_add_uint( h261_tree, hf_h261_gobn, tvb, offset, 1, tvb_get_guint8( tvb, offset ) >> 4 );
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/* MBAP 2nd octet, 4 bits, 3rd octet 1 bit */
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proto_tree_add_uint( h261_tree, hf_h261_mbap, tvb, offset, 1,
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( tvb_get_guint8( tvb, offset ) & 15 )
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+ ( tvb_get_guint8( tvb, offset + 1 ) >> 7 ) );
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offset++;
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/* QUANT 3rd octet, 5 bits (starting at bit 2!) */
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proto_tree_add_uint( h261_tree, hf_h261_mbap, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 124 );
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/* HMDV 3rd octet 2 bits, 4th octet 3 bits */
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proto_tree_add_uint( h261_tree, hf_h261_mbap, tvb, offset, 1,
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( ( tvb_get_guint8( tvb, offset ) << 4) >> 4 )
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+ ( tvb_get_guint8( tvb, offset ) >> 5 ) );
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offset++;
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/* VMVD 4th octet, last 5 bits */
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proto_tree_add_uint( h261_tree, hf_h261_mbap, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 31 );
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offset++;
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/* The rest of the packet is the H.261 stream */
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proto_tree_add_bytes( h261_tree, hf_h261_data, tvb, offset, tvb_length_remaining( tvb, offset ), tvb_get_ptr( tvb, offset, tvb_length_remaining( tvb, offset ) ) );
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}
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}
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void
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proto_register_h261(void)
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{
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static hf_register_info hf[] =
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{
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{
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&hf_h261_sbit,
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{
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"Start bit position",
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"h261.sbit",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_ebit,
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{
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"End bit position",
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"h261.ebit",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_ibit,
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{
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"Intra frame encoded data flag",
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"h261.i",
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FT_BOOLEAN,
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BASE_NONE,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_vbit,
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{
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"Motion vector flag",
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"h261.v",
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FT_BOOLEAN,
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BASE_NONE,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_gobn,
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{
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"GOB Number",
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"h261.gobn",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_mbap,
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{
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"Macroblock address predictor",
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"h261.mbap",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_quant,
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{
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"Quantizer",
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"h261.quant",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_hmvd,
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{
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"Horizontal motion vctor data",
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"h261.hmvd",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_vmvd,
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{
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"Vertical motion vector data",
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"h261.vmvd",
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FT_UINT8,
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BASE_DEC,
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NULL,
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0x0,
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"", HFILL
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}
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},
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{
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&hf_h261_data,
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{
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"H.261 stream",
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"h261.stream",
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FT_BYTES,
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BASE_NONE,
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NULL,
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0x0,
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"", HFILL
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}
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},
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};
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static gint *ett[] =
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{
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&ett_h261,
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};
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proto_h261 = proto_register_protocol("ITU-T Recommendation H.261",
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"H.261", "h261");
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proto_register_field_array(proto_h261, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_dissector("h261", dissect_h261, proto_h261);
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}
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