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Diffstat (limited to 'epan/dissectors/packet-h261.c')
| -rw-r--r-- | epan/dissectors/packet-h261.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/epan/dissectors/packet-h261.c b/epan/dissectors/packet-h261.c new file mode 100644 index 00000000..cfd1f410 --- /dev/null +++ b/epan/dissectors/packet-h261.c @@ -0,0 +1,259 @@ +/* packet-h261.c + * + * Routines for ITU-T Recommendation H.261 dissection + * + * Copyright 2000, Philips Electronics N.V. + * Andreas Sikkema <h323@ramdyne.nl> + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 1998 Gerald Combs + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +/* + * This dissector tries to dissect the H.261 protocol according to Annex C + * of ITU-T Recommendation H.225.0 (02/98) + */ + + +#include "config.h" + +#include <epan/packet.h> + +#include <epan/rtp_pt.h> +#include <epan/iax2_codec_type.h> + +void proto_register_h261(void); +void proto_reg_handoff_h261(void); + +static dissector_handle_t h261_handle; + +/* 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 int +dissect_h261( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_ ) +{ + proto_item *ti = NULL; + proto_tree *h261_tree = NULL; + unsigned int offset = 0; + static int * const bits[] = { + /* SBIT 1st octet, 3 bits */ + &hf_h261_sbit, + /* EBIT 1st octet, 3 bits */ + &hf_h261_ebit, + /* I flag, 1 bit */ + &hf_h261_ibit, + /* V flag, 1 bit */ + &hf_h261_vbit, + NULL + }; + + col_set_str(pinfo->cinfo, COL_PROTOCOL, "H.261"); + + col_set_str(pinfo->cinfo, COL_INFO, "H.261 message"); + + ti = proto_tree_add_item( tree, proto_h261, tvb, offset, -1, ENC_NA); + h261_tree = proto_item_add_subtree( ti, ett_h261 ); + + proto_tree_add_bitmask_list(h261_tree, tvb, offset, 1, bits, ENC_NA); + offset++; + + /* GOBN 2nd octet, 4 bits */ + proto_tree_add_item( h261_tree, hf_h261_gobn, tvb, offset, 1, ENC_NA); + /* MBAP 2nd octet, 4 bits, 3rd octet 1 bit */ + proto_tree_add_item( h261_tree, hf_h261_mbap, tvb, offset, 2, ENC_BIG_ENDIAN); + offset++; + + /* QUANT 3rd octet, 5 bits (starting at bit 2!) */ + proto_tree_add_item( h261_tree, hf_h261_quant, tvb, offset, 1, ENC_NA); + + /* HMVD 3rd octet 2 bits, 4th octet 3 bits */ + proto_tree_add_item( h261_tree, hf_h261_hmvd, tvb, offset, 2, ENC_BIG_ENDIAN); + offset++; + + /* VMVD 4th octet, last 5 bits */ + proto_tree_add_item( h261_tree, hf_h261_vmvd, tvb, offset, 1, ENC_NA); + offset++; + + /* The rest of the packet is the H.261 stream */ + proto_tree_add_item( h261_tree, hf_h261_data, tvb, offset, -1, ENC_NA); + + return tvb_captured_length(tvb); +} + +void +proto_register_h261(void) +{ + static hf_register_info hf[] = + { + { + &hf_h261_sbit, + { + "Start bit position", + "h261.sbit", + FT_UINT8, + BASE_DEC, + NULL, + 0xe0, + NULL, HFILL + } + }, + { + &hf_h261_ebit, + { + "End bit position", + "h261.ebit", + FT_UINT8, + BASE_DEC, + NULL, + 0x1c, + NULL, HFILL + } + }, + { + &hf_h261_ibit, + { + "Intra frame encoded data flag", + "h261.i", + FT_BOOLEAN, + 8, + NULL, + 0x02, + NULL, HFILL + } + }, + { + &hf_h261_vbit, + { + "Motion vector flag", + "h261.v", + FT_BOOLEAN, + 8, + NULL, + 0x01, + NULL, HFILL + } + }, + { + &hf_h261_gobn, + { + "GOB Number", + "h261.gobn", + FT_UINT8, + BASE_DEC, + NULL, + 0xF0, + NULL, HFILL + } + }, + { + &hf_h261_mbap, + { + "Macroblock address predictor", + "h261.mbap", + FT_UINT16, + BASE_DEC, + NULL, + 0x0F80, + NULL, HFILL + } + }, + { + &hf_h261_quant, + { + "Quantizer", + "h261.quant", + FT_UINT8, + BASE_DEC, + NULL, + 0x7C, + NULL, HFILL + } + }, + { + &hf_h261_hmvd, + { + "Horizontal motion vector data", + "h261.hmvd", + FT_UINT16, + BASE_DEC, + NULL, + 0x03E0, + NULL, HFILL + } + }, + { + &hf_h261_vmvd, + { + "Vertical motion vector data", + "h261.vmvd", + FT_UINT8, + BASE_DEC, + NULL, + 0x0, + NULL, HFILL + } + }, + { + &hf_h261_data, + { + "H.261 stream", + "h261.stream", + FT_BYTES, + BASE_NONE, + NULL, + 0x0, + NULL, 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)); + + h261_handle = register_dissector("h261", dissect_h261, proto_h261); +} + +void +proto_reg_handoff_h261(void) +{ + dissector_add_uint("rtp.pt", PT_H261, h261_handle); + dissector_add_uint("iax2.codec", AST_FORMAT_H261, h261_handle); +} + +/* + * Editor modelines - https://www.wireshark.org/tools/modelines.html + * + * Local variables: + * c-basic-offset: 8 + * tab-width: 8 + * indent-tabs-mode: t + * End: + * + * vi: set shiftwidth=8 tabstop=8 noexpandtab: + * :indentSize=8:tabSize=8:noTabs=false: + */ |