forked from osmocom/wireshark
260 lines
4.9 KiB
C
260 lines
4.9 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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* Copyright 2000, Philips Electronics N.V.
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* Andreas Sikkema <h323@ramdyne.nl>
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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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* SPDX-License-Identifier: GPL-2.0-or-later
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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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#include "config.h"
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#include <epan/packet.h>
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#include <epan/rtp_pt.h>
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#include <epan/iax2_codec_type.h>
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void proto_register_h261(void);
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void proto_reg_handoff_h261(void);
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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 int
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dissect_h261( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_ )
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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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static int * const bits[] = {
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/* SBIT 1st octet, 3 bits */
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&hf_h261_sbit,
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/* EBIT 1st octet, 3 bits */
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&hf_h261_ebit,
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/* I flag, 1 bit */
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&hf_h261_ibit,
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/* V flag, 1 bit */
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&hf_h261_vbit,
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NULL
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};
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "H.261");
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col_set_str(pinfo->cinfo, COL_INFO, "H.261 message");
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if ( tree ) {
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ti = proto_tree_add_item( tree, proto_h261, tvb, offset, -1, ENC_NA );
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h261_tree = proto_item_add_subtree( ti, ett_h261 );
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proto_tree_add_bitmask_list(h261_tree, tvb, offset, 1, bits, ENC_NA);
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offset++;
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/* GOBN 2nd octet, 4 bits */
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proto_tree_add_item( h261_tree, hf_h261_gobn, tvb, offset, 1, ENC_NA);
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/* MBAP 2nd octet, 4 bits, 3rd octet 1 bit */
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proto_tree_add_item( h261_tree, hf_h261_mbap, tvb, offset, 1, ENC_BIG_ENDIAN);
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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_item( h261_tree, hf_h261_quant, tvb, offset, 1, ENC_NA );
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/* HMVD 3rd octet 2 bits, 4th octet 3 bits */
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proto_tree_add_item( h261_tree, hf_h261_hmvd, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset++;
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/* VMVD 4th octet, last 5 bits */
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proto_tree_add_item( h261_tree, hf_h261_vmvd, tvb, offset, 1, 0x1F );
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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_item( h261_tree, hf_h261_data, tvb, offset, -1, ENC_NA );
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}
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return tvb_captured_length(tvb);
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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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0xe0,
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NULL, 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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0x1c,
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NULL, 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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8,
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NULL,
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0x02,
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NULL, 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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8,
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NULL,
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0x01,
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NULL, 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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0xF0,
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NULL, 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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0x0E80,
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NULL, 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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0x7C,
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NULL, 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 vector 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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0x03E0,
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NULL, 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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NULL, 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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NULL, 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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}
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void
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proto_reg_handoff_h261(void)
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{
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dissector_handle_t h261_handle;
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h261_handle = create_dissector_handle(dissect_h261, proto_h261);
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dissector_add_uint("rtp.pt", PT_H261, h261_handle);
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dissector_add_uint("iax2.codec", AST_FORMAT_H261, h261_handle);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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