t38_gateway.c File Reference

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <string.h>
#include "floating_fudge.h"
#include <assert.h>
#include <tiffio.h>
#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/queue.h"
#include "spandsp/dc_restore.h"
#include "spandsp/bit_operations.h"
#include "spandsp/power_meter.h"
#include "spandsp/complex.h"
#include "spandsp/tone_detect.h"
#include "spandsp/tone_generate.h"
#include "spandsp/async.h"
#include "spandsp/crc.h"
#include "spandsp/hdlc.h"
#include "spandsp/silence_gen.h"
#include "spandsp/fsk.h"
#include "spandsp/v29rx.h"
#include "spandsp/v29tx.h"
#include "spandsp/v27ter_rx.h"
#include "spandsp/v27ter_tx.h"
#include "spandsp/v17rx.h"
#include "spandsp/v17tx.h"
#include "spandsp/super_tone_rx.h"
#include "spandsp/modem_connect_tones.h"
#include "spandsp/t4.h"
#include "spandsp/t30_fcf.h"
#include "spandsp/t35.h"
#include "spandsp/t30.h"
#include "spandsp/t30_logging.h"
#include "spandsp/fax_modems.h"
#include "spandsp/t38_core.h"
#include "spandsp/t38_non_ecm_buffer.h"
#include "spandsp/t38_gateway.h"
#include "config.h"
#include <tgmath.h>
#include <math.h>


Defines
#define	MS_PER_TX_CHUNK 30
#define	HDLC_START_BUFFER_LEVEL 8
#define	INDICATOR_TX_COUNT 3
#define	DATA_TX_COUNT 1
#define	DATA_END_TX_COUNT 3
#define	MAX_NSX_SUPPRESSION 10
#define	HDLC_FRAMING_OK_THRESHOLD 5
Enumerations
enum	{ DISBIT1 = 0x01, DISBIT2 = 0x02, DISBIT3 = 0x04, DISBIT4 = 0x08, DISBIT5 = 0x10, DISBIT6 = 0x20, DISBIT7 = 0x40, DISBIT8 = 0x80 }
enum	{ T38_NONE, T38_V27TER_RX, T38_V29_RX, T38_V17_RX }
enum	{ HDLC_FLAG_FINISHED = 0x01, HDLC_FLAG_CORRUPT_CRC = 0x02, HDLC_FLAG_PROCEED_WITH_OUTPUT = 0x04, HDLC_FLAG_MISSING_DATA = 0x08 }
enum	{ FLAG_INDICATOR = 0x100, FLAG_DATA = 0x200 }
Functions
int	t38_gateway_rx (t38_gateway_state_t *s, int16_t amp[], int len)
	Process a block of received FAX audio samples.
int	t38_gateway_tx (t38_gateway_state_t *s, int16_t amp[], int max_len)
	Generate a block of FAX audio samples.
void	t38_gateway_get_transfer_statistics (t38_gateway_state_t s, t38_stats_t t)
	Get the current transfer statistics.
void	t38_gateway_set_ecm_capability (t38_gateway_state_t *s, int ecm_allowed)
	Control whether error correcting mode (ECM) is allowed.
void	t38_gateway_set_transmit_on_idle (t38_gateway_state_t *s, int transmit_on_idle)
	Select whether silent audio will be sent when transmit is idle.
void	t38_gateway_set_supported_modems (t38_gateway_state_t *s, int supported_modems)
	Specify supported modems.
void	t38_gateway_set_nsx_suppression (t38_gateway_state_t s, const uint8_t from_t38, int from_t38_len, const uint8_t *from_modem, int from_modem_len)
	Select whether NSC, NSF, and NSS should be suppressed.
void	t38_gateway_set_tep_mode (t38_gateway_state_t *s, int use_tep)
	Select whether TEP will be sent for the image modems.
void	t38_gateway_set_fill_bit_removal (t38_gateway_state_t *s, int remove)
	Select whether non-ECM fill bits are to be removed during transmission.
void	t38_gateway_set_real_time_frame_handler (t38_gateway_state_t s, t38_gateway_real_time_frame_handler_t handler, void *user_data)
	Set a callback function for T.30 frame exchange monitoring.
t38_gateway_state_t *	t38_gateway_init (t38_gateway_state_t s, t38_tx_packet_handler_t tx_packet_handler, void *tx_packet_user_data)
	Initialise a gateway mode T.38 context.
int	t38_gateway_free (t38_gateway_state_t *s)
	Free a T.38 context.

Detailed Description

Function Documentation

int t38_gateway_free ( t38_gateway_state_t * s )

Free a T.38 context.

Free a gateway mode T.38 context.

Parameters:

s

The T.38 context.

Returns:: 0 for OK, else -1.

void t38_gateway_get_transfer_statistics	(	t38_gateway_state_t *	s,
		t38_stats_t *	t
	)

Get the current transfer statistics.

Get the current transfer statistics for the current T.38 session.

Parameters:

	s	The T.38 context.
	t	A pointer to a buffer for the statistics.

References t38_gateway_state_s::core, t38_gateway_core_state_t::ecm_mode, t38_gateway_core_state_t::fast_bit_rate, and t38_gateway_core_state_t::pages_confirmed.

t38_gateway_state_t* t38_gateway_init	(	t38_gateway_state_t *	s,
		t38_tx_packet_handler_t *	tx_packet_handler,
		void *	tx_packet_user_data
	)

Initialise a gateway mode T.38 context.

Parameters:

	s	The T.38 context.
	tx_packet_handler	A callback routine to encapsulate and transmit T.38 packets.
	tx_packet_user_data	An opaque pointer passed to the tx_packet_handler routine.

Returns:: A pointer to the termination mode T.38 context, or NULL if there was a problem.

References t38_gateway_state_s::audio, fax_modems_state_t::audio_rx_log, fax_modems_state_t::audio_tx_log, t38_gateway_state_s::core, t38_gateway_core_state_t::ecm_allowed, t38_gateway_state_s::logging, t38_gateway_audio_state_t::modems, t38_gateway_core_state_t::non_ecm_to_modem, t38_gateway_set_nsx_suppression(), t38_gateway_set_supported_modems(), t38_non_ecm_buffer_init(), and t38_gateway_core_state_t::to_t38.

int t38_gateway_rx	(	t38_gateway_state_t *	s,
		int16_t	amp[],
		int	len
	)

Process a block of received FAX audio samples.

Parameters:

	s	The T.38 context.
	amp	The audio sample buffer.
	len	The number of samples in the buffer.

Returns:: The number of samples unprocessed.

References t38_gateway_state_s::audio, fax_modems_state_t::audio_rx_log, t38_gateway_state_s::core, fax_modems_state_t::dc_restore, t38_gateway_audio_state_t::modems, fax_modems_state_t::rx_handler, fax_modems_state_t::rx_user_data, t38_gateway_core_state_t::samples_to_timeout, and t38_gateway_core_state_t::tcf_mode_predictable_modem_start.

void t38_gateway_set_ecm_capability	(	t38_gateway_state_t *	s,
		int	ecm_allowed
	)

Control whether error correcting mode (ECM) is allowed.

Parameters:

	s	The T.38 context.
	ecm_allowed	TRUE is ECM is to be allowed.

References t38_gateway_state_s::core, and t38_gateway_core_state_t::ecm_allowed.

void t38_gateway_set_fill_bit_removal	(	t38_gateway_state_t *	s,
		int	remove
	)

Select whether non-ECM fill bits are to be removed during transmission.

Parameters:

	s	The T.38 context.
	remove	TRUE if fill bits are to be removed.

References t38_gateway_state_s::core, and t38_gateway_core_state_t::to_t38.

void t38_gateway_set_nsx_suppression	(	t38_gateway_state_t *	s,
		const uint8_t *	from_t38,
		int	from_t38_len,
		const uint8_t *	from_modem,
		int	from_modem_len
	)

Select whether NSC, NSF, and NSS should be suppressed.

Select whether NSC, NSF, and NSS should be suppressed. It selected, the contents of these messages are forced to zero for all octets beyond the message type. This makes them look like manufacturer specific messages, from a manufacturer which does not exist.

Parameters:

	s	The T.38 context.
	from_t38	A string of bytes to overwrite the header of any NSC, NSF, and NSS frames passing through the gateway from T.38 the the modem.
	from_t38_len	The length of the overwrite string.
	from_modem	A string of bytes to overwrite the header of any NSC, NSF, and NSS frames passing through the gateway from the modem to T.38.
	from_modem_len	The length of the overwrite string.

References t38_gateway_t38_state_t::suppress_nsx_len, and t38_gateway_state_s::t38x.

Referenced by t38_gateway_init().

void t38_gateway_set_real_time_frame_handler	(	t38_gateway_state_t *	s,
		t38_gateway_real_time_frame_handler_t *	handler,
		void *	user_data
	)

Set a callback function for T.30 frame exchange monitoring.

Set a callback function for T.30 frame exchange monitoring. This is called from the heart of the signal processing, so don't take too long in the handler routine.

Parameters:

	s	The T.30 context.
	handler	The callback function.
	user_data	An opaque pointer passed to the callback function.

References t38_gateway_state_s::core, t38_gateway_core_state_t::real_time_frame_handler, and t38_gateway_core_state_t::real_time_frame_user_data.

void t38_gateway_set_supported_modems	(	t38_gateway_state_t *	s,
		int	supported_modems
	)

Specify supported modems.

Specify which modem types are supported by a T.30 context.

Parameters:

	s	The T.38 context.
	supported_modems	Bit field list of the supported modems.

References t38_gateway_state_s::core, t38_core_state_s::fastest_image_data_rate, t38_gateway_core_state_t::supported_modems, t38_gateway_t38_state_t::t38, and t38_gateway_state_s::t38x.

Referenced by t38_gateway_init().

void t38_gateway_set_tep_mode	(	t38_gateway_state_t *	s,
		int	use_tep
	)

Select whether TEP will be sent for the image modems.

Select whether talker echo protection tone will be sent for the image modems.

Parameters:

	s	The T.38 context.
	use_tep	TRUE if TEP should be sent.

References t38_gateway_state_s::audio, t38_gateway_audio_state_t::modems, and fax_modems_state_t::use_tep.

void t38_gateway_set_transmit_on_idle	(	t38_gateway_state_t *	s,
		int	transmit_on_idle
	)

Select whether silent audio will be sent when transmit is idle.

Parameters:

	s	The T.38 context.
	transmit_on_idle	TRUE if silent audio should be output when the FAX transmitter is idle. FALSE to transmit zero length audio when the FAX transmitter is idle. The default behaviour is FALSE.

References t38_gateway_state_s::audio, t38_gateway_audio_state_t::modems, and fax_modems_state_t::transmit_on_idle.

int t38_gateway_tx	(	t38_gateway_state_t *	s,
		int16_t	amp[],
		int	max_len
	)

Generate a block of FAX audio samples.

Parameters:

	s	The T.38 context.
	amp	The audio sample buffer.
	max_len	The number of samples to be generated.

Returns:: The number of samples actually generated.

References t38_gateway_state_s::audio, fax_modems_state_t::audio_tx_log, t38_gateway_audio_state_t::modems, fax_modems_state_t::silence_gen, silence_gen_set(), fax_modems_state_t::transmit_on_idle, fax_modems_state_t::tx_handler, and fax_modems_state_t::tx_user_data.

t38_gateway.c File Reference

Defines

Enumerations

Functions

Detailed Description

Function Documentation