/* packet-2dparityfec.c * Mark Lewis * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ /* ** RTP Payload dissector for packets as specified in: ** Pro-MPEG Code of Practice #3 release 2 ** ** This protocol defines a format for FEC data embedded within RTP packets with ** a payload type of 96 (0x60). The format of the FEC packets, which reside within ** the RTP payload, is as follows... ** ** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ** | SNBase low bits | Length Recovery | ** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ** |E| PT recovery | Mask | ** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ** | TS recovery | ** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ** |X|D|type |index| Offset | NA |SNBase ext bits| ** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ** | | ** : FEC Payload : ** | | ** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ** ** For more information on this protocol see... ** http://www.pro-mpeg.org/publications/pdf/Vid-on-IP-CoP3-r2.pdf ** ** ** Notes: ** ** This protocol always resides in RTP packets with payload type 96. However, ** type 96 is dynamic and may refer to other protocols. As Pro-MPEG FEC must ** function in the absence of a control channel, and because this data is ** likely to be transmitted within closed networks, no automatic mechanism ** exists for specifying the existence of Pro-MPEG FEC on payload type 96. ** This dissector is thus disabled by default. Dissection of this protocol ** may be enabled from the 2dparityfec panel under Preferences->Protocols. ** ** Mark Lewis - 20th June 2006 */ #include "config.h" #include #include /* forward reference */ void proto_register_2dparityfec(void); void proto_reg_handoff_2dparityfec(void); static dissector_handle_t handle_2dparityfec; static bool dissect_fec; static int fec_rtp_payload_type = 96; static int proto_2dparityfec; static int hf_2dparityfec_index; static int hf_2dparityfec_length_recovery; static int hf_2dparityfec_mask; static int hf_2dparityfec_na; static int hf_2dparityfec_offset; static int hf_2dparityfec_payload; static int hf_2dparityfec_pt_recovery; static int hf_2dparityfec_rfc2733_ext; static int hf_2dparityfec_row_flag; static int hf_2dparityfec_snbase_ext; static int hf_2dparityfec_snbase_low; static int hf_2dparityfec_ts_pro_mpeg_ext; static int hf_2dparityfec_ts_recovery; static int hf_2dparityfec_type; static int ett_2dparityfec; static const value_string fec_type_names[] = { {0, "XOR"}, {1, "Hamming"}, {2, "Reed-Solomon"}, {0, NULL} }; static int dissect_2dparityfec(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { uint8_t OffsetField; uint8_t NAField; uint32_t SNBase; uint8_t D; /* Extract SNBase */ SNBase = (uint32_t)tvb_get_uint8(tvb, 0)<<8; SNBase |= (uint32_t)tvb_get_uint8(tvb, 1); SNBase |= (uint32_t)tvb_get_uint8(tvb, 15)<<16; /* Extract D */ D = (tvb_get_uint8(tvb, 12)>>6) & 0x1; /* Extract Offset and NA */ OffsetField = tvb_get_uint8(tvb, 13); NAField = tvb_get_uint8(tvb, 14); col_set_str(pinfo->cinfo, COL_PROTOCOL, "2dFEC"); /* Configure the info column */ if(D) { col_add_fstr(pinfo->cinfo, COL_INFO, "Row FEC - SNBase=%u, Offset=%u, NA=%u", SNBase, OffsetField, NAField); } else { col_add_fstr(pinfo->cinfo, COL_INFO, "Column FEC - SNBase=%u, Offset=%u, NA=%u", SNBase, OffsetField, NAField); } if(tree) { /* we are being asked for details */ proto_item *ti; proto_tree *tree_2dparityfec; int offset = 0; ti = proto_tree_add_item(tree, proto_2dparityfec, tvb, 0, -1, ENC_NA); tree_2dparityfec = proto_item_add_subtree(ti, ett_2dparityfec); proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_snbase_low, tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_length_recovery, tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_rfc2733_ext, tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_pt_recovery, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_mask, tvb, offset, 3, ENC_BIG_ENDIAN); offset += 3; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_ts_recovery, tvb, offset, 4, ENC_BIG_ENDIAN); offset += 4; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_ts_pro_mpeg_ext, tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_row_flag, tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_type, tvb, offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_index, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_offset, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_na, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_snbase_ext, tvb, offset, 1, ENC_BIG_ENDIAN); offset += 1; proto_tree_add_item(tree_2dparityfec, hf_2dparityfec_payload, tvb, offset, -1, ENC_NA); } return tvb_captured_length(tvb); } void proto_register_2dparityfec(void) { static hf_register_info hf[] = { { &hf_2dparityfec_snbase_low, { "SNBase low", "2dparityfec.snbase_low", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_2dparityfec_length_recovery, { "Length recovery", "2dparityfec.lr", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_2dparityfec_rfc2733_ext, { "RFC2733 Extension (E)", "2dparityfec.e", FT_BOOLEAN, 8, NULL, 0x80, NULL, HFILL } }, { &hf_2dparityfec_pt_recovery, { "Payload Type recovery", "2dparityfec.ptr", FT_UINT8, BASE_HEX, NULL, 0x7f, NULL, HFILL } }, { &hf_2dparityfec_mask, { "Mask", "2dparityfec.mask", /*FT_UINT32*/FT_UINT24, BASE_HEX, NULL, /*0x00ffffff*/0x0, NULL, HFILL } }, { &hf_2dparityfec_ts_recovery, { "Timestamp recovery", "2dparityfec.tsr", FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_2dparityfec_ts_pro_mpeg_ext, { "Pro-MPEG Extension (X)", "2dparityfec.x", FT_BOOLEAN, 8, NULL, 0x80, NULL, HFILL } }, { &hf_2dparityfec_row_flag, { "Row FEC (D)", "2dparityfec.d", FT_BOOLEAN, 8, NULL, 0x40, NULL, HFILL } }, { &hf_2dparityfec_type, { "Type", "2dparityfec.type", FT_UINT8, BASE_DEC, VALS(fec_type_names), 0x38, NULL, HFILL } }, { &hf_2dparityfec_index, { "Index", "2dparityfec.index", FT_UINT8, BASE_DEC, NULL, 0x07, NULL, HFILL } }, { &hf_2dparityfec_offset, { "Offset", "2dparityfec.offset", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_2dparityfec_na, { "NA", "2dparityfec.na", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_2dparityfec_snbase_ext, { "SNBase ext", "2dparityfec.snbase_ext", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_2dparityfec_payload, { "FEC Payload", "2dparityfec.payload", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, }; /* Setup protocol subtree array */ static int *ett[] = { &ett_2dparityfec, }; module_t *module_2dparityfec; proto_2dparityfec = proto_register_protocol("Pro-MPEG Code of Practice #3 release 2 FEC Protocol", "2dparityfec", "2dparityfec"); proto_register_field_array(proto_2dparityfec, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); module_2dparityfec = prefs_register_protocol(proto_2dparityfec, proto_reg_handoff_2dparityfec); prefs_register_bool_preference(module_2dparityfec, "enable", "Decode Pro-MPEG FEC on RTP dynamic payload type 96", "Enable this option to recognise all traffic on RTP dynamic payload type 96 (0x60) " "as FEC data corresponding to Pro-MPEG Code of Practice #3 release 2", &dissect_fec); handle_2dparityfec = register_dissector("2dparityfec", dissect_2dparityfec, proto_2dparityfec); } void proto_reg_handoff_2dparityfec(void) { if (dissect_fec) { dissector_add_uint("rtp.pt", fec_rtp_payload_type, handle_2dparityfec); } else { dissector_delete_uint("rtp.pt", fec_rtp_payload_type, handle_2dparityfec); } } /* * Editor modelines * * Local Variables: * c-basic-offset: 3 * tab-width: 8 * indent-tabs-mode: nil * End: * * ex: set shiftwidth=3 tabstop=8 expandtab: * :indentSize=3:tabSize=8:noTabs=true: */