spandsp  0.0.6
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.
31 */
33 {
34  /*! \brief Handler routine to transmit IFP packets generated by the T.38 protocol engine */
35  t38_tx_packet_handler_t *tx_packet_handler;
36  /*! \brief An opaque pointer passed to tx_packet_handler */
38 
39  /*! \brief Handler routine to process received indicator packets */
40  t38_rx_indicator_handler_t *rx_indicator_handler;
41  /*! \brief Handler routine to process received data packets */
42  t38_rx_data_handler_t *rx_data_handler;
43  /*! \brief Handler routine to process the missing packet condition */
44  t38_rx_missing_handler_t *rx_missing_handler;
45  /*! \brief An opaque pointer passed to any of the above receive handling routines */
46  void *rx_user_data;
47 
48  /*! NOTE - Bandwidth reduction shall only be done on suitable Phase C data, i.e., MH, MR
49  and - in the case of transcoding to JBIG - MMR. MMR and JBIG require reliable data
50  transport such as that provided by TCP. When transcoding is selected, it shall be
51  applied to every suitable page in a call. */
52 
53  /*! \brief Method 1: Local generation of TCF (required for use with TCP).
54  Method 2: Transfer of TCF is required for use with UDP (UDPTL or RTP).
55  Method 2 is not recommended for use with TCP. */
57 
58  /*! \brief The emitting gateway may indicate a preference for either UDP/UDPTL, or
59  UDP/RTP, or TCP for transport of T.38 IFP Packets. The receiving device
60  selects the transport protocol. */
62 
63  /*! \brief Indicates the capability to remove and insert fill bits in Phase C, non-ECM
64  data to reduce bandwidth in the packet network. */
66 
67  /*! \brief Indicates the ability to convert to/from MMR from/to the line format to
68  improve the compression of the data, and reduce the bandwidth, in the
69  packet network. */
71 
72  /*! \brief Indicates the ability to convert to/from JBIG to reduce bandwidth. */
74 
75  /*! \brief For UDP (UDPTL or RTP) modes, this option indicates the maximum
76  number of octets that can be stored on the remote device before an
77  overflow condition occurs. It is the responsibility of the transmitting
78  application to limit the transfer rate to prevent an overflow. The
79  negotiated data rate should be used to determine the rate at which
80  data is being removed from the buffer. */
82 
83  /*! \brief This option indicates the maximum size of a UDPTL packet or the
84  maximum size of the payload within an RTP packet that can be accepted
85  by the remote device. */
87 
88  /*! \brief This is the version number of ITU-T Rec. T.38. New versions shall be
89  compatible with previous versions. */
91 
92  /*! \brief Allow time for TEP playout */
94 
95  /*! \brief The fastest data rate supported by the T.38 channel. */
97 
98  /*! \brief The number of times each packet type will be sent (low byte). The
99  depth of redundancy (2nd byte). Higher numbers may increase reliability
100  for UDP transmission. Zero is valid for the indicator packet category,
101  to suppress all indicator packets (typicaly for TCP transmission). */
103 
104  /*! \brief TRUE if IFP packet sequence numbers are relevant. For some transports, like TPKT
105  over TCP they are not relevent. */
107 
108  /*! \brief The sequence number for the next packet to be transmitted */
110  /*! \brief The sequence number expected in the next received packet */
112 
113  /*! \brief The current receive indicator - i.e. the last indicator received */
115  /*! \brief The current receive data type - i.e. the last data type received */
117  /*! \brief The current receive field type - i.e. the last field_type received */
119  /*! \brief The current transmit indicator - i.e. the last indicator transmitted */
121  /*! \brief The bit rate for V.34 operation */
122  int v34_rate;
123 
124  /*! A count of missing receive packets. This count might not be accurate if the
125  received packet numbers jump wildly. */
127 
128  /*! \brief Error and flow logging control */
130 };
131 
132 #endif
133 /*- End of file ------------------------------------------------------------*/
int 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:106
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:61
int fastest_image_data_rate
The fastest data rate supported by the T.38 channel.
Definition: private/t38_core.h:96
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:56
int v34_rate
The bit rate for V.34 operation.
Definition: private/t38_core.h:122
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:86
int rx_expected_seq_no
The sequence number expected in the next received packet.
Definition: private/t38_core.h:111
void * tx_packet_user_data
An opaque pointer passed to tx_packet_handler.
Definition: private/t38_core.h:37
t38_rx_indicator_handler_t * rx_indicator_handler
Handler routine to process received indicator packets.
Definition: private/t38_core.h:40
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:90
int missing_packets
Definition: private/t38_core.h:126
int jbig_transcoding
Indicates the ability to convert to/from JBIG to reduce bandwidth.
Definition: private/t38_core.h:73
logging_state_t logging
Error and flow logging control.
Definition: private/t38_core.h:129
t38_rx_missing_handler_t * rx_missing_handler
Handler routine to process the missing packet condition.
Definition: private/t38_core.h:44
void * rx_user_data
An opaque pointer passed to any of the above receive handling routines.
Definition: private/t38_core.h:46
int current_rx_data_type
The current receive data type - i.e. the last data type received.
Definition: private/t38_core.h:116
t38_rx_data_handler_t * rx_data_handler
Handler routine to process received data packets.
Definition: private/t38_core.h:42
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:65
Definition: private/logging.h:33
int current_rx_indicator
The current receive indicator - i.e. the last indicator received.
Definition: private/t38_core.h:114
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:70
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:81
int tx_seq_no
The sequence number for the next packet to be transmitted.
Definition: private/t38_core.h:109
int current_rx_field_type
The current receive field type - i.e. the last field_type received.
Definition: private/t38_core.h:118
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:35
int allow_for_tep
Allow time for TEP playout.
Definition: private/t38_core.h:93
int current_tx_indicator
The current transmit indicator - i.e. the last indicator transmitted.
Definition: private/t38_core.h:120
Definition: private/t38_core.h:32
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:102