spandsp 3.0.0
private/t38_core.h
1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * private/t38_core.h - An implementation of T.38, less the packet exchange part
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2005 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License version 2.1,
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26#if !defined(_SPANDSP_PRIVATE_T38_CORE_H_)
27#define _SPANDSP_PRIVATE_T38_CORE_H_
28
29/*!
30 Core T.38 state, common to all modes of T.38. Higher layers should support the specifics
31 of a gateway, terminal, T.31 interface, etc and incorporate an instance of this structure
32 to handle the basics of T.38, mostly IFP.
33*/
35{
36 /*! \brief Handler routine to transmit IFP packets generated by the T.38 protocol engine */
37 t38_tx_packet_handler_t tx_packet_handler;
38 /*! \brief An opaque pointer passed to tx_packet_handler */
40
41 /*! \brief Handler routine to process received indicator packets */
42 t38_rx_indicator_handler_t rx_indicator_handler;
43 /*! \brief Handler routine to process received data packets */
44 t38_rx_data_handler_t rx_data_handler;
45 /*! \brief Handler routine to process the missing packet condition */
46 t38_rx_missing_handler_t rx_missing_handler;
47 /*! \brief An opaque pointer passed to any of the above receive handling routines */
49
50 /*! \brief Required time between T.38 transmissions, in us. */
52 /*! \brief Bit fields controlling the way data is packed into chunks for transmission. */
54 /*! \brief Internet Aware FAX mode bit mask. */
55 int iaf;
56
57 /*! NOTE - Bandwidth reduction shall only be done on suitable Phase C data, i.e., MH, MR
58 and - in the case of transcoding to JBIG - MMR. MMR and JBIG require reliable data
59 transport such as that provided by TCP. When transcoding is selected, it shall be
60 applied to every suitable page in a call. */
61
62 /*! \brief Method 1: Local generation of TCF (required for use with TCP).
63 Method 2: Transfer of TCF is required for use with UDP (UDPTL or RTP).
64 Method 2 is not recommended for use with TCP. */
66
67 /*! \brief The emitting gateway may indicate a preference for either UDP/UDPTL, or
68 UDP/RTP, or TCP for transport of T.38 IFP Packets. The receiving device
69 selects the transport protocol. */
71
72 /*! \brief Indicates the capability to remove and insert fill bits in Phase C, non-ECM
73 data to reduce bandwidth in the packet network. */
75
76 /*! \brief Indicates the ability to convert to/from MMR from/to the line format to
77 improve the compression of the data, and reduce the bandwidth, in the
78 packet network. */
80
81 /*! \brief Indicates the ability to convert to/from JBIG to reduce bandwidth. */
83
84 /*! \brief For UDP (UDPTL or RTP) modes, this option indicates the maximum
85 number of octets that can be stored on the remote device before an
86 overflow condition occurs. It is the responsibility of the transmitting
87 application to limit the transfer rate to prevent an overflow. The
88 negotiated data rate should be used to determine the rate at which
89 data is being removed from the buffer. */
91
92 /*! \brief This option indicates the maximum size of a UDPTL packet or the
93 maximum size of the payload within an RTP packet that can be accepted
94 by the remote device. */
96
97 /*! \brief This is the version number of ITU-T Rec. T.38. New versions shall be
98 compatible with previous versions. */
100
101 /*! \brief Allow time for TEP playout */
103
104 /*! \brief The fastest data rate supported by the T.38 channel. */
106
107 /*! \brief Pace transmission */
109
110 /*! \brief True if IFP packet sequence numbers are relevant. For some transports, like TPKT
111 over TCP they are not relevent. */
113
114 /*! \brief The number of times each packet type will be sent (low byte). The
115 depth of redundancy (2nd byte). Higher numbers may increase reliability
116 for UDP transmission. Zero is valid for the indicator packet category,
117 to suppress all indicator packets (typicaly for TCP transmission). */
119
120 /*! \brief The sequence number for the next packet to be transmitted */
122 /*! \brief The sequence number expected in the next received packet */
124
125 /*! \brief The current receive indicator - i.e. the last indicator received */
127 /*! \brief The current receive data type - i.e. the last data type received */
129 /*! \brief The current receive field type - i.e. the last field_type received */
131 /*! \brief The current transmit indicator - i.e. the last indicator transmitted */
133 /*! \brief The bit rate for V.34 operation */
135
136 /*! A count of missing receive packets. This count might not be accurate if the
137 received packet numbers jump wildly. */
139
140 /*! \brief Error and flow logging control */
142};
143
144#endif
145/*- End of file ------------------------------------------------------------*/
struct logging_state_s logging_state_t
Definition logging.h:72
Definition private/t38_core.h:35
int current_tx_indicator
The current transmit indicator - i.e. the last indicator transmitted.
Definition private/t38_core.h:132
int current_rx_field_type
The current receive field type - i.e. the last field_type received.
Definition private/t38_core.h:130
int missing_packets
Definition private/t38_core.h:138
int tx_seq_no
The sequence number for the next packet to be transmitted.
Definition private/t38_core.h:121
int max_buffer_size
For UDP (UDPTL or RTP) modes, this option indicates the maximum number of octets that can be stored o...
Definition private/t38_core.h:90
t38_tx_packet_handler_t tx_packet_handler
Handler routine to transmit IFP packets generated by the T.38 protocol engine.
Definition private/t38_core.h:37
int fastest_image_data_rate
The fastest data rate supported by the T.38 channel.
Definition private/t38_core.h:105
int fill_bit_removal
Indicates the capability to remove and insert fill bits in Phase C, non-ECM data to reduce bandwidth ...
Definition private/t38_core.h:74
t38_rx_missing_handler_t rx_missing_handler
Handler routine to process the missing packet condition.
Definition private/t38_core.h:46
int data_transport_protocol
The emitting gateway may indicate a preference for either UDP/UDPTL, or UDP/RTP, or TCP for transport...
Definition private/t38_core.h:70
int max_datagram_size
This option indicates the maximum size of a UDPTL packet or the maximum size of the payload within an...
Definition private/t38_core.h:95
void * rx_user_data
An opaque pointer passed to any of the above receive handling routines.
Definition private/t38_core.h:48
t38_rx_data_handler_t rx_data_handler
Handler routine to process received data packets.
Definition private/t38_core.h:44
int rx_expected_seq_no
The sequence number expected in the next received packet.
Definition private/t38_core.h:123
int pace_transmission
Pace transmission.
Definition private/t38_core.h:108
int chunking_modes
Bit fields controlling the way data is packed into chunks for transmission.
Definition private/t38_core.h:53
t38_rx_indicator_handler_t rx_indicator_handler
Handler routine to process received indicator packets.
Definition private/t38_core.h:42
int jbig_transcoding
Indicates the ability to convert to/from JBIG to reduce bandwidth.
Definition private/t38_core.h:82
int v34_rate
The bit rate for V.34 operation.
Definition private/t38_core.h:134
void * tx_packet_user_data
An opaque pointer passed to tx_packet_handler.
Definition private/t38_core.h:39
int t38_version
This is the version number of ITU-T Rec. T.38. New versions shall be compatible with previous version...
Definition private/t38_core.h:99
int microseconds_per_tx_chunk
Required time between T.38 transmissions, in us.
Definition private/t38_core.h:51
int iaf
Internet Aware FAX mode bit mask.
Definition private/t38_core.h:55
int current_rx_data_type
The current receive data type - i.e. the last data type received.
Definition private/t38_core.h:128
int current_rx_indicator
The current receive indicator - i.e. the last indicator received.
Definition private/t38_core.h:126
logging_state_t logging
Error and flow logging control.
Definition private/t38_core.h:141
int category_control[5]
The number of times each packet type will be sent (low byte). The depth of redundancy (2nd byte)....
Definition private/t38_core.h:118
int mmr_transcoding
Indicates the ability to convert to/from MMR from/to the line format to improve the compression of th...
Definition private/t38_core.h:79
int data_rate_management_method
Method 1: Local generation of TCF (required for use with TCP). Method 2: Transfer of TCF is required ...
Definition private/t38_core.h:65
bool check_sequence_numbers
True if IFP packet sequence numbers are relevant. For some transports, like TPKT over TCP they are no...
Definition private/t38_core.h:112
int allow_for_tep
Allow time for TEP playout.
Definition private/t38_core.h:102