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 1.1 2008/10/13 13:14:01 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 fax_modems_state_t modems; 00063 /*! \brief The current receive signal handler. Actual receiving hop between this 00064 and a dummy receive routine. */ 00065 span_rx_handler_t *base_rx_handler; 00066 } t38_gateway_audio_state_t; 00067 00068 typedef struct 00069 { 00070 /*! \brief non-ECM and HDLC modem receive data buffer. */ 00071 uint8_t data[T38_RX_BUF_LEN]; 00072 /*! \brief Current pointer into the data buffer. */ 00073 int data_ptr; 00074 /*! \brief The current octet being received as non-ECM data. */ 00075 unsigned int bit_stream; 00076 /*! \brief The number of bits taken from the modem for the current scan row. This 00077 is used during non-ECM transmission will fill bit removal to see that 00078 T.38 packet transmissions do not stretch too far apart. */ 00079 int bits_absorbed; 00080 /*! \brief The current bit number in the current non-ECM octet. */ 00081 int bit_no; 00082 /*! \brief Progressively calculated CRC for HDLC messages received from a modem. */ 00083 uint16_t crc; 00084 /*! \brief TRUE if non-ECM fill bits are to be stripped when sending image data. */ 00085 int fill_bit_removal; 00086 /*! \brief The number of octets to send in each image packet (non-ECM or ECM) at the current 00087 rate and the current specified packet interval. */ 00088 int octets_per_data_packet; 00089 00090 int in_bits; 00091 int out_octets; 00092 } t38_gateway_to_t38_state_t; 00093 00094 typedef struct 00095 { 00096 /*! \brief HDLC message buffers. */ 00097 uint8_t buf[T38_MAX_HDLC_LEN]; 00098 /*! \brief HDLC message lengths. */ 00099 int len; 00100 /*! \brief HDLC message status flags. */ 00101 int flags; 00102 /*! \brief HDLC buffer contents. */ 00103 int contents; 00104 } t38_gateway_hdlc_buf_t; 00105 00106 typedef struct 00107 { 00108 /*! \brief HDLC message buffers. */ 00109 t38_gateway_hdlc_buf_t buf[T38_TX_HDLC_BUFS]; 00110 #if 0 00111 /*! \brief HDLC message buffers. */ 00112 uint8_t buf[T38_TX_HDLC_BUFS][T38_MAX_HDLC_LEN]; 00113 /*! \brief HDLC message lengths. */ 00114 int len[T38_TX_HDLC_BUFS]; 00115 /*! \brief HDLC message status flags. */ 00116 int flags[T38_TX_HDLC_BUFS]; 00117 /*! \brief HDLC buffer contents. */ 00118 int contents[T38_TX_HDLC_BUFS]; 00119 #endif 00120 /*! \brief HDLC buffer number for input. */ 00121 int in; 00122 /*! \brief HDLC buffer number for output. */ 00123 int out; 00124 } t38_gateway_hdlc_state_t; 00125 00126 /*! 00127 T.38 gateway core descriptor. 00128 */ 00129 typedef struct 00130 { 00131 /*! \brief A bit mask of the currently supported modem types. */ 00132 int supported_modems; 00133 /*! \brief TRUE if ECM FAX mode is allowed through the gateway. */ 00134 int ecm_allowed; 00135 00136 /*! \brief TRUE if in image data modem is to use short training. This usually 00137 follows image_data_mode, but in ECM mode T.30 defines recovery 00138 conditions in which long training is used for image data. */ 00139 int short_train; 00140 /*! \brief TRUE if in image data mode, as opposed to TCF mode. */ 00141 int image_data_mode; 00142 /*! \brief The minimum permitted bits per FAX scan line row. */ 00143 int min_row_bits; 00144 00145 /*! \brief TRUE if we should count the next MCF as a page end, else FALSE */ 00146 int count_page_on_mcf; 00147 /*! \brief The number of pages for which a confirm (MCF) message was returned. */ 00148 int pages_confirmed; 00149 00150 /*! \brief TRUE if we are in error correcting (ECM) mode */ 00151 int ecm_mode; 00152 /*! \brief The current bit rate for the fast modem. */ 00153 int fast_bit_rate; 00154 /*! \brief The current fast modem type. */ 00155 int fast_modem; 00156 /*! \brief The type of fast receive modem currently active, which may be T38_NONE */ 00157 int fast_rx_active; 00158 00159 /*! \brief TRUE if between DCS and TCF, and we want the fast image modem to 00160 start in the T.38 data at a predictable time from the end of the 00161 V.21 signal. */ 00162 int tcf_mode_predictable_modem_start; 00163 00164 /*! \brief The number of samples until the next timeout event */ 00165 int samples_to_timeout; 00166 00167 /*! Buffer for HDLC and non-ECM data going to the T.38 channel */ 00168 t38_gateway_to_t38_state_t to_t38; 00169 /*! Buffer for data going to an HDLC modem. */ 00170 t38_gateway_hdlc_state_t hdlc_to_modem; 00171 /*! Buffer for data going to a non-ECM mode modem. */ 00172 t38_non_ecm_buffer_state_t non_ecm_to_modem; 00173 00174 /*! \brief A pointer to a callback routine to be called when frames are 00175 exchanged. */ 00176 t38_gateway_real_time_frame_handler_t *real_time_frame_handler; 00177 /*! \brief An opaque pointer supplied in real time frame callbacks. */ 00178 void *real_time_frame_user_data; 00179 } t38_gateway_core_state_t; 00180 00181 /*! 00182 T.38 gateway state. 00183 */ 00184 struct t38_gateway_state_s 00185 { 00186 t38_gateway_t38_state_t t38x; 00187 t38_gateway_audio_state_t audio; 00188 t38_gateway_core_state_t core; 00189 00190 /*! \brief Error and flow logging control */ 00191 logging_state_t logging; 00192 }; 00193 00194 #endif 00195 /*- End of file ------------------------------------------------------------*/