private/t38_gateway.h

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00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * private/t38_gateway.h - A T.38, less the packet exchange part
00005  *
00006  * Written by Steve Underwood <steveu@coppice.org>
00007  *
00008  * Copyright (C) 2005, 2006, 2007 Steve Underwood
00009  *
00010  * All rights reserved.
00011  *
00012  * This program is free software; you can redistribute it and/or modify
00013  * it under the terms of the GNU Lesser General Public License version 2.1,
00014  * as published by the Free Software Foundation.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License along with this program; if not, write to the Free Software
00023  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00024  *
00025  * $Id: t38_gateway.h,v 1.3 2009/04/12 14:18:02 steveu Exp $
00026  */
00027 
00028 /*! \file */
00029 
00030 #if !defined(_SPANDSP_PRIVATE_T38_GATEWAY_H_)
00031 #define _SPANDSP_PRIVATE_T38_GATEWAY_H_
00032 
00033 /*!
00034     T.38 gateway T.38 side channel descriptor.
00035 */
00036 typedef struct
00037 {
00038     /*! Core T.38 IFP support */
00039     t38_core_state_t t38;
00040 
00041     /*! \brief TRUE if the NSF, NSC, and NSS are to be suppressed by altering
00042                their contents to something the far end will not recognise. */
00043     int suppress_nsx_len[2];
00044     /*! \brief TRUE if we need to corrupt the HDLC frame in progress, so the receiver cannot
00045                interpret it. The two values are for the two directions. */
00046     int corrupt_current_frame[2];
00047 
00048     /*! \brief the current class of field being received - i.e. none, non-ECM or HDLC */
00049     int current_rx_field_class;
00050     /*! \brief The T.38 indicator currently in use */
00051     int in_progress_rx_indicator;
00052 
00053     /*! \brief The current T.38 data type being sent. */
00054     int current_tx_data_type;
00055 } t38_gateway_t38_state_t;
00056 
00057 /*!
00058     T.38 gateway audio side channel descriptor.
00059 */
00060 typedef struct
00061 {
00062     /*! \brief The FAX modem set for the audio side fo the gateway. */
00063     fax_modems_state_t modems;
00064     /*! \brief The current receive signal handler. Actual receiving hop between this
00065                and a dummy receive routine. */
00066     span_rx_handler_t *base_rx_handler;
00067 } t38_gateway_audio_state_t;
00068 
00069 /*!
00070     T.38 gateway T.38 side state.
00071 */
00072 typedef struct
00073 {
00074     /*! \brief non-ECM and HDLC modem receive data buffer. */
00075     uint8_t data[T38_RX_BUF_LEN];
00076     /*! \brief Current pointer into the data buffer. */
00077     int data_ptr;
00078     /*! \brief The current octet being received as non-ECM data. */
00079     unsigned int bit_stream;
00080     /*! \brief The number of bits taken from the modem for the current scan row. This
00081                is used during non-ECM transmission will fill bit removal to see that
00082                T.38 packet transmissions do not stretch too far apart. */
00083     int bits_absorbed;
00084     /*! \brief The current bit number in the current non-ECM octet. */
00085     int bit_no;
00086     /*! \brief Progressively calculated CRC for HDLC messages received from a modem. */
00087     uint16_t crc;
00088     /*! \brief TRUE if non-ECM fill bits are to be stripped when sending image data. */
00089     int fill_bit_removal;
00090     /*! \brief The number of octets to send in each image packet (non-ECM or ECM) at the current
00091                rate and the current specified packet interval. */
00092     int octets_per_data_packet;
00093 
00094     /*! \brief Bits into the non-ECM buffer */
00095     int in_bits;
00096     /*! \brief Octets fed out from the non-ECM buffer */
00097     int out_octets;
00098 } t38_gateway_to_t38_state_t;
00099 
00100 /*!
00101     T.38 gateway HDLC buffer.
00102 */
00103 typedef struct
00104 {
00105     /*! \brief HDLC message buffers. */
00106     uint8_t buf[T38_MAX_HDLC_LEN];
00107     /*! \brief HDLC message lengths. */
00108     int len;
00109     /*! \brief HDLC message status flags. */
00110     int flags;
00111     /*! \brief HDLC buffer contents. */
00112     int contents;
00113 } t38_gateway_hdlc_buf_t;
00114 
00115 /*!
00116     T.38 gateway HDLC state.
00117 */
00118 typedef struct
00119 {
00120     /*! \brief HDLC message buffers. */
00121     t38_gateway_hdlc_buf_t buf[T38_TX_HDLC_BUFS];
00122 #if 0
00123     /*! \brief HDLC message buffers. */
00124     uint8_t buf[T38_TX_HDLC_BUFS][T38_MAX_HDLC_LEN];
00125     /*! \brief HDLC message lengths. */
00126     int len[T38_TX_HDLC_BUFS];
00127     /*! \brief HDLC message status flags. */
00128     int flags[T38_TX_HDLC_BUFS];
00129     /*! \brief HDLC buffer contents. */
00130     int contents[T38_TX_HDLC_BUFS];
00131 #endif
00132     /*! \brief HDLC buffer number for input. */
00133     int in;
00134     /*! \brief HDLC buffer number for output. */
00135     int out;
00136 } t38_gateway_hdlc_state_t;
00137 
00138 /*!
00139     T.38 gateway core descriptor.
00140 */
00141 typedef struct
00142 {
00143     /*! \brief A bit mask of the currently supported modem types. */
00144     int supported_modems;
00145     /*! \brief TRUE if ECM FAX mode is allowed through the gateway. */
00146     int ecm_allowed;
00147 
00148     /*! \brief TRUE if in image data modem is to use short training. This usually
00149                follows image_data_mode, but in ECM mode T.30 defines recovery
00150                conditions in which long training is used for image data. */
00151     int short_train;
00152     /*! \brief TRUE if in image data mode, as opposed to TCF mode. */
00153     int image_data_mode;
00154     /*! \brief The minimum permitted bits per FAX scan line row. */
00155     int min_row_bits;
00156 
00157     /*! \brief TRUE if we should count the next MCF as a page end, else FALSE */
00158     int count_page_on_mcf;
00159     /*! \brief The number of pages for which a confirm (MCF) message was returned. */
00160     int pages_confirmed;
00161 
00162     /*! \brief TRUE if we are in error correcting (ECM) mode */
00163     int ecm_mode;
00164     /*! \brief The current bit rate for the fast modem. */
00165     int fast_bit_rate;
00166     /*! \brief The current fast modem type. */
00167     int fast_modem;
00168     /*! \brief The type of fast receive modem currently active, which may be T38_NONE */
00169     int fast_rx_active;
00170 
00171     /*! \brief TRUE if between DCS and TCF, and we want the fast image modem to
00172                start in the T.38 data at a predictable time from the end of the
00173                V.21 signal. */
00174     int tcf_mode_predictable_modem_start;
00175 
00176     /*! \brief The number of samples until the next timeout event */
00177     int samples_to_timeout;
00178 
00179     /*! Buffer for HDLC and non-ECM data going to the T.38 channel */
00180     t38_gateway_to_t38_state_t to_t38;
00181     /*! Buffer for data going to an HDLC modem. */
00182     t38_gateway_hdlc_state_t hdlc_to_modem;
00183     /*! Buffer for data going to a non-ECM mode modem. */
00184     t38_non_ecm_buffer_state_t non_ecm_to_modem;
00185 
00186     /*! \brief A pointer to a callback routine to be called when frames are
00187         exchanged. */
00188     t38_gateway_real_time_frame_handler_t *real_time_frame_handler;
00189     /*! \brief An opaque pointer supplied in real time frame callbacks. */
00190     void *real_time_frame_user_data;
00191 } t38_gateway_core_state_t;
00192 
00193 /*!
00194     T.38 gateway state.
00195 */
00196 struct t38_gateway_state_s
00197 {
00198     /*! T.38 side state */
00199     t38_gateway_t38_state_t t38x;
00200     /*! Audio side state */
00201     t38_gateway_audio_state_t audio;
00202     /*! T.38 core state */
00203     t38_gateway_core_state_t core;
00204 
00205     /*! \brief Error and flow logging control */
00206     logging_state_t logging;
00207 };
00208 
00209 #endif
00210 /*- End of file ------------------------------------------------------------*/

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