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Diffstat (limited to 'epan/dissectors/packet-h261.c')
| -rw-r--r-- | epan/dissectors/packet-h261.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/epan/dissectors/packet-h261.c b/epan/dissectors/packet-h261.c new file mode 100644 index 0000000000..8b291d2e9b --- /dev/null +++ b/epan/dissectors/packet-h261.c @@ -0,0 +1,263 @@ +/* packet-h261.c + * + * Routines for ITU-T Recommendation H.261 dissection + * + * $Id$ + * + * Copyright 2000, Philips Electronics N.V. + * Andreas Sikkema <h323@ramdyne.nl> + * + * Ethereal - Network traffic analyzer + * By Gerald Combs <gerald@ethereal.com> + * 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. + */ + +/* + * This dissector tries to dissect the H.261 protocol according to Annex C + * of ITU-T Recommendation H.225.0 (02/98) + */ + + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +#include <glib.h> +#include <epan/packet.h> + +#include <stdio.h> +#include <string.h> + +#include "rtp_pt.h" + +/* H.261 header fields */ +static int proto_h261 = -1; +static int hf_h261_sbit = -1; +static int hf_h261_ebit = -1; +static int hf_h261_ibit = -1; +static int hf_h261_vbit = -1; +static int hf_h261_gobn = -1; +static int hf_h261_mbap = -1; +static int hf_h261_quant = -1; +static int hf_h261_hmvd = -1; /* Mislabeled in a figure in section C.3.1 as HMDV */ +static int hf_h261_vmvd = -1; +static int hf_h261_data = -1; + +/* H.261 fields defining a sub tree */ +static gint ett_h261 = -1; + +static void +dissect_h261( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree ) +{ + proto_item *ti = NULL; + proto_tree *h261_tree = NULL; + unsigned int offset = 0; + + if ( check_col( pinfo->cinfo, COL_PROTOCOL ) ) { + col_set_str( pinfo->cinfo, COL_PROTOCOL, "H.261" ); + } + + if ( check_col( pinfo->cinfo, COL_INFO) ) { + col_set_str( pinfo->cinfo, COL_INFO, "H.261 message"); + } + + if ( tree ) { + ti = proto_tree_add_item( tree, proto_h261, tvb, offset, -1, FALSE ); + h261_tree = proto_item_add_subtree( ti, ett_h261 ); + /* SBIT 1st octet, 3 bits */ + proto_tree_add_uint( h261_tree, hf_h261_sbit, tvb, offset, 1, tvb_get_guint8( tvb, offset ) >> 5 ); + /* EBIT 1st octet, 3 bits */ + proto_tree_add_uint( h261_tree, hf_h261_ebit, tvb, offset, 1, ( tvb_get_guint8( tvb, offset ) << 3 ) >> 5 ); + /* I flag, 1 bit */ + proto_tree_add_boolean( h261_tree, hf_h261_ibit, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 2 ); + /* V flag, 1 bit */ + proto_tree_add_boolean( h261_tree, hf_h261_vbit, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 1 ); + offset++; + + /* GOBN 2nd octet, 4 bits */ + proto_tree_add_uint( h261_tree, hf_h261_gobn, tvb, offset, 1, tvb_get_guint8( tvb, offset ) >> 4 ); + /* MBAP 2nd octet, 4 bits, 3rd octet 1 bit */ + proto_tree_add_uint( h261_tree, hf_h261_mbap, tvb, offset, 1, + ( tvb_get_guint8( tvb, offset ) & 15 ) + + ( tvb_get_guint8( tvb, offset + 1 ) >> 7 ) ); + offset++; + + /* QUANT 3rd octet, 5 bits (starting at bit 2!) */ + proto_tree_add_uint( h261_tree, hf_h261_quant, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 124 ); + + /* HMVD 3rd octet 2 bits, 4th octet 3 bits */ + proto_tree_add_uint( h261_tree, hf_h261_hmvd, tvb, offset, 2, + ( ( tvb_get_guint8( tvb, offset ) & 0x03 ) << 3 ) + + ( tvb_get_guint8( tvb, offset+1 ) >> 5 ) ); + offset++; + + /* VMVD 4th octet, last 5 bits */ + proto_tree_add_uint( h261_tree, hf_h261_vmvd, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 31 ); + offset++; + + /* The rest of the packet is the H.261 stream */ + proto_tree_add_item( h261_tree, hf_h261_data, tvb, offset, -1, FALSE ); + } +} + +void +proto_register_h261(void) +{ + static hf_register_info hf[] = + { + { + &hf_h261_sbit, + { + "Start bit position", + "h261.sbit", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_ebit, + { + "End bit position", + "h261.ebit", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_ibit, + { + "Intra frame encoded data flag", + "h261.i", + FT_BOOLEAN, + BASE_NONE, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_vbit, + { + "Motion vector flag", + "h261.v", + FT_BOOLEAN, + BASE_NONE, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_gobn, + { + "GOB Number", + "h261.gobn", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_mbap, + { + "Macroblock address predictor", + "h261.mbap", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_quant, + { + "Quantizer", + "h261.quant", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_hmvd, + { + "Horizontal motion vector data", + "h261.hmvd", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_vmvd, + { + "Vertical motion vector data", + "h261.vmvd", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + "", HFILL + } + }, + { + &hf_h261_data, + { + "H.261 stream", + "h261.stream", + FT_BYTES, + BASE_NONE, + NULL, + 0x0, + "", HFILL + } + }, +}; + + static gint *ett[] = + { + &ett_h261, + }; + + + proto_h261 = proto_register_protocol("ITU-T Recommendation H.261", + "H.261", "h261"); + proto_register_field_array(proto_h261, hf, array_length(hf)); + proto_register_subtree_array(ett, array_length(ett)); +} + +void +proto_reg_handoff_h261(void) +{ + dissector_handle_t h261_handle; + + h261_handle = create_dissector_handle(dissect_h261, proto_h261); + dissector_add("rtp.pt", PT_H261, h261_handle); +} |