Classes
struct	hdlc_rx_stats_t

Macros
#define	HDLC_MAXFRAME_LEN 400

Typedefs
typedef void(*	hdlc_frame_handler_t) (void user_data, const uint8_t pkt, int len, int ok)
typedef void(*	hdlc_underflow_handler_t) (void *user_data)
typedef struct hdlc_rx_state_s	hdlc_rx_state_t
typedef struct hdlc_tx_state_s	hdlc_tx_state_t

Functions
hdlc_rx_state_t *	hdlc_rx_init (hdlc_rx_state_t s, int crc32, int report_bad_frames, int framing_ok_threshold, hdlc_frame_handler_t handler, void user_data)
	Initialise an HDLC receiver context.
int	hdlc_rx_restart (hdlc_rx_state_t *s)
	Re-initialise an HDLC receiver context.
void	hdlc_rx_set_frame_handler (hdlc_rx_state_t s, hdlc_frame_handler_t handler, void user_data)
	Change the put_bit function associated with an HDLC receiver context.
void	hdlc_rx_set_status_handler (hdlc_rx_state_t s, modem_status_func_t handler, void user_data)
	Change the status report function associated with an HDLC receiver context.
int	hdlc_rx_release (hdlc_rx_state_t *s)
	Release an HDLC receiver context.
int	hdlc_rx_free (hdlc_rx_state_t *s)
	Free an HDLC receiver context.
void	hdlc_rx_set_max_frame_len (hdlc_rx_state_t *s, size_t max_len)
	Set the maximum frame length for an HDLC receiver context.
void	hdlc_rx_set_octet_counting_report_interval (hdlc_rx_state_t *s, int interval)
	Set the octet counting report interval.
int	hdlc_rx_get_stats (hdlc_rx_state_t s, hdlc_rx_stats_t t)
	Get the current receive statistics.
	SPAN_DECLARE_NONSTD (void) hdlc_rx_put_bit(hdlc_rx_state_t *s
	Put a single bit of data to an HDLC receiver.
hdlc_tx_state_t *	hdlc_tx_init (hdlc_tx_state_t s, int crc32, int inter_frame_flags, int progressive, hdlc_underflow_handler_t handler, void user_data)
	Initialise an HDLC transmitter context.
int	hdlc_tx_restart (hdlc_tx_state_t *s)
	Re-initialise an HDLC transmitter context.
int	hdlc_tx_release (hdlc_tx_state_t *s)
	Release an HDLC transmitter context.
int	hdlc_tx_free (hdlc_tx_state_t *s)
	Free an HDLC transmitter context.
void	hdlc_tx_set_max_frame_len (hdlc_tx_state_t *s, size_t max_len)
	Set the maximum frame length for an HDLC transmitter context.
int	hdlc_tx_frame (hdlc_tx_state_t s, const uint8_t frame, size_t len)
	Transmit a frame.
int	hdlc_tx_corrupt_frame (hdlc_tx_state_t *s)
	Corrupt the frame currently being transmitted, by giving it the wrong CRC.
int	hdlc_tx_flags (hdlc_tx_state_t *s, int len)
	Transmit a specified quantity of flag octets, typically as a preamble.
int	hdlc_tx_abort (hdlc_tx_state_t *s)
	Send an abort.
	SPAN_DECLARE_NONSTD (int) hdlc_tx_get_bit(hdlc_tx_state_t *s)
	Get the next bit for transmission.

Variables
int	new_bit
int	new_byte
const uint8_t	buf []
const uint8_t int	len
uint8_t size_t	max_len

Macro Definition Documentation

◆ HDLC_MAXFRAME_LEN

#define HDLC_MAXFRAME_LEN 400

HDLC_MAXFRAME_LEN is the maximum length of a stuffed HDLC frame, excluding the CRC.

Referenced by hdlc_tx_corrupt_frame(), hdlc_tx_frame(), hdlc_tx_init(), and hdlc_tx_set_max_frame_len().

Typedef Documentation

◆ hdlc_rx_state_t

typedef struct hdlc_rx_state_s hdlc_rx_state_t

HDLC receive descriptor. This contains all the state information for an HDLC receiver.

◆ hdlc_tx_state_t

typedef struct hdlc_tx_state_s hdlc_tx_state_t

HDLC transmit descriptor. This contains all the state information for an HDLC transmitter.

Function Documentation

◆ hdlc_rx_free()

int hdlc_rx_free ( hdlc_rx_state_t * s )

Free an HDLC receiver context.

Parameters

s	A pointer to an HDLC receiver context.

Returns: 0 for OK

◆ hdlc_rx_get_stats()

int hdlc_rx_get_stats	(	hdlc_rx_state_t *	s,
		hdlc_rx_stats_t *	t )

Get the current receive statistics.

Parameters

s	A pointer to an HDLC receiver context.
t	A pointer to the buffer for the statistics.

Returns: 0 for OK, else -1.

References hdlc_rx_stats_t::aborts, hdlc_rx_stats_t::bytes, hdlc_rx_stats_t::crc_errors, hdlc_rx_stats_t::good_frames, hdlc_rx_stats_t::length_errors, hdlc_rx_state_s::rx_aborts, hdlc_rx_state_s::rx_bytes, hdlc_rx_state_s::rx_crc_errors, hdlc_rx_state_s::rx_frames, and hdlc_rx_state_s::rx_length_errors.

◆ hdlc_rx_init()

hdlc_rx_state_t * hdlc_rx_init	(	hdlc_rx_state_t *	s,
		int	crc32,
		int	report_bad_frames,
		int	framing_ok_threshold,
		hdlc_frame_handler_t	handler,
		void *	user_data )

Initialise an HDLC receiver context.

Parameters

s	A pointer to an HDLC receiver context.
crc32	TRUE to use ITU CRC32. FALSE to use ITU CRC16.
report_bad_frames	TRUE to request the reporting of bad frames.
framing_ok_threshold	The number of back-to-back flags needed to start the framing OK condition. This may be used where a series of flag octets is used as a preamble, such as in the T.30 protocol.
handler	The function to be called when a good HDLC frame is received.
user_data	An opaque parameter for the callback routine.

Returns: A pointer to the HDLC receiver context.

References hdlc_rx_state_s::buffer, hdlc_rx_state_s::crc_bytes, hdlc_rx_state_s::frame_handler, hdlc_rx_state_s::frame_user_data, hdlc_rx_state_s::framing_ok_threshold, hdlc_rx_state_s::max_frame_len, and hdlc_rx_state_s::report_bad_frames.

Referenced by v42_restart().

◆ hdlc_rx_release()

int hdlc_rx_release ( hdlc_rx_state_t * s )

Release an HDLC receiver context.

Parameters

s	A pointer to an HDLC receiver context.

Returns: 0 for OK

◆ hdlc_rx_restart()

int hdlc_rx_restart ( hdlc_rx_state_t * s )

Re-initialise an HDLC receiver context.

Re-initialise an HDLC receiver context. This does not reset the usage statistics.

Parameters

s	A pointer to an HDLC receiver context.

Returns: 0 for success.

References hdlc_rx_state_s::byte_in_progress, hdlc_rx_state_s::flags_seen, hdlc_rx_state_s::framing_ok_announced, hdlc_rx_state_s::len, hdlc_rx_state_s::num_bits, hdlc_rx_state_s::octet_count, hdlc_rx_state_s::octet_counting_mode, and hdlc_rx_state_s::raw_bit_stream.

◆ hdlc_rx_set_frame_handler()

void hdlc_rx_set_frame_handler	(	hdlc_rx_state_t *	s,
		hdlc_frame_handler_t	handler,
		void *	user_data )

Change the put_bit function associated with an HDLC receiver context.

Parameters

s	A pointer to an HDLC receiver context.
handler	The function to be called when a good HDLC frame is received.
user_data	An opaque parameter for the callback routine.

References hdlc_rx_state_s::frame_handler, and hdlc_rx_state_s::frame_user_data.

◆ hdlc_rx_set_max_frame_len()

void hdlc_rx_set_max_frame_len	(	hdlc_rx_state_t *	s,
		size_t	max_len )

Set the maximum frame length for an HDLC receiver context.

Parameters

s	A pointer to an HDLC receiver context.
max_len	The maximum permitted length of a frame.

References hdlc_rx_state_s::buffer, hdlc_rx_state_s::crc_bytes, and hdlc_rx_state_s::max_frame_len.

◆ hdlc_rx_set_octet_counting_report_interval()

void hdlc_rx_set_octet_counting_report_interval	(	hdlc_rx_state_t *	s,
		int	interval )

Set the octet counting report interval.

Parameters

s	A pointer to an HDLC receiver context.
interval	The interval, in octets.

References hdlc_rx_state_s::octet_count_report_interval.

◆ hdlc_rx_set_status_handler()

void hdlc_rx_set_status_handler	(	hdlc_rx_state_t *	s,
		modem_status_func_t	handler,
		void *	user_data )

Change the status report function associated with an HDLC receiver context.

Parameters

s	A pointer to an HDLC receiver context.
handler	The callback routine used to report status changes.
user_data	An opaque parameter for the callback routine.

References hdlc_rx_state_s::status_handler, and hdlc_rx_state_s::status_user_data.

◆ hdlc_tx_abort()

int hdlc_tx_abort ( hdlc_tx_state_t * s )

Send an abort.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: 0 if the frame was aborted, else -1.

References hdlc_tx_state_s::abort_octets, and hdlc_tx_state_s::flag_octets.

◆ hdlc_tx_corrupt_frame()

int hdlc_tx_corrupt_frame ( hdlc_tx_state_t * s )

Corrupt the frame currently being transmitted, by giving it the wrong CRC.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: 0 if the frame was corrupted, else -1.

References hdlc_tx_state_s::buffer, hdlc_tx_state_s::crc, HDLC_MAXFRAME_LEN, and hdlc_tx_state_s::len.

◆ hdlc_tx_flags()

int hdlc_tx_flags	(	hdlc_tx_state_t *	s,
		int	len )

Transmit a specified quantity of flag octets, typically as a preamble.

Parameters

s	A pointer to an HDLC transmitter context.
len	The length of the required period of flags, in flag octets. If len is zero this requests that HDLC transmission be terminated when the buffers have fully drained.

Returns: 0 if the flags were accepted for transmission, else -1.

References hdlc_tx_state_s::flag_octets, hdlc_tx_state_s::pos, hdlc_tx_state_s::report_flag_underflow, and hdlc_tx_state_s::tx_end.

◆ hdlc_tx_frame()

int hdlc_tx_frame	(	hdlc_tx_state_t *	s,
		const uint8_t *	frame,
		size_t	len )

Transmit a frame.

Parameters

s	A pointer to an HDLC transmitter context.
frame	A pointer to the frame to be transmitted.
len	The length of the frame to be transmitted.

Returns: 0 if the frame was accepted for transmission, else -1.

References hdlc_tx_state_s::buffer, hdlc_tx_state_s::crc, hdlc_tx_state_s::crc_bytes, crc_itu16_calc(), crc_itu32_calc(), HDLC_MAXFRAME_LEN, hdlc_tx_state_s::len, hdlc_tx_state_s::max_frame_len, hdlc_tx_state_s::pos, hdlc_tx_state_s::progressive, and hdlc_tx_state_s::tx_end.

◆ hdlc_tx_free()

int hdlc_tx_free ( hdlc_tx_state_t * s )

Free an HDLC transmitter context.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: 0 for OK

◆ hdlc_tx_init()

hdlc_tx_state_t * hdlc_tx_init	(	hdlc_tx_state_t *	s,
		int	crc32,
		int	inter_frame_flags,
		int	progressive,
		hdlc_underflow_handler_t	handler,
		void *	user_data )

Initialise an HDLC transmitter context.

Parameters

s	A pointer to an HDLC transmitter context.
crc32	TRUE to use ITU CRC32. FALSE to use ITU CRC16.
inter_frame_flags	The minimum flag octets to insert between frames (usually one).
progressive	TRUE if frame creation works in progressive mode.
handler	The callback function called when the HDLC transmitter underflows.
user_data	An opaque parameter for the callback routine.

Returns: A pointer to the HDLC transmitter context.

References hdlc_tx_state_s::crc, hdlc_tx_state_s::crc_bytes, HDLC_MAXFRAME_LEN, hdlc_tx_state_s::idle_octet, hdlc_tx_state_s::inter_frame_flags, hdlc_tx_state_s::max_frame_len, hdlc_tx_state_s::progressive, hdlc_tx_state_s::underflow_handler, and hdlc_tx_state_s::user_data.

Referenced by v42_restart().

◆ hdlc_tx_release()

int hdlc_tx_release ( hdlc_tx_state_t * s )

Release an HDLC transmitter context.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: 0 for OK

◆ hdlc_tx_restart()

int hdlc_tx_restart ( hdlc_tx_state_t * s )

Re-initialise an HDLC transmitter context.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: 0 for success.

References hdlc_tx_state_s::abort_octets, hdlc_tx_state_s::bits, hdlc_tx_state_s::byte, hdlc_tx_state_s::crc, hdlc_tx_state_s::crc_bytes, hdlc_tx_state_s::flag_octets, hdlc_tx_state_s::idle_octet, hdlc_tx_state_s::len, hdlc_tx_state_s::num_bits, hdlc_tx_state_s::octets_in_progress, hdlc_tx_state_s::pos, hdlc_tx_state_s::report_flag_underflow, and hdlc_tx_state_s::tx_end.

◆ hdlc_tx_set_max_frame_len()

void hdlc_tx_set_max_frame_len	(	hdlc_tx_state_t *	s,
		size_t	max_len )

Set the maximum frame length for an HDLC transmitter context.

Parameters

s	A pointer to an HDLC transmitter context.
max_len	The maximum length.

References HDLC_MAXFRAME_LEN, and hdlc_tx_state_s::max_frame_len.

◆ SPAN_DECLARE_NONSTD() [1/2]

SPAN_DECLARE_NONSTD ( int )

Get the next bit for transmission.

Get the next bit of a transmitted serial bit stream.

Get the next sequence of bytes for transmission.

Get the next byte for transmission.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: The next bit for transmission.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: The next byte for transmission.

Parameters

s	A pointer to an HDLC transmitter context.
buf	The buffer for the data.
max_len	The number of bytes to get.

Returns: The number of bytes actually got.

Apply T.30 receive processing to a block of audio samples.

Process a block of received V.8 audio samples.

Fake processing of a missing block of received V.29 modem audio samples.

Fake processing of a missing block of received V.27ter modem audio samples.

Generate a block of V.22bis modem audio samples.

Fake processing of a missing block of received V.22bis modem audio samples.

Process a block of received V.18 audio samples.

Fake processing of a missing block of received V.17 modem audio samples.

Generate a block of FAX audio samples.

Apply fake received audio processing.

Process a received T.38 IFP packet from a reliable stream (e.g. TCP).

Generate a block of T.31 modem audio samples.

Fake processing of a missing block of received T.31 modem audio samples.

Dummy receive fillin callback.

Dummy receive callback.

Process a block of samples through an instance of the modem connect tones detector.

Get the next sequence of bytes for transmission.

Get the next byte for transmission.

Fake processing of a missing block of received FSK modem audio samples.

Process a block of received FSK modem audio samples.

Apply T.30 transmit processing to generate a block of audio samples.

Apply fake T.30 receive processing.

Get the next bit of a transmitted serial bit stream.

Parameters

user_data An opaque point which must point to a transmitter context.

Returns: the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended.

Apply fake T.30 receive processing when a block of audio samples is missing (e.g due to packet loss).

Parameters

s	The FAX context.
len	The number of samples to fake.

Returns: The number of samples unprocessed. This should only be non-zero if the software has reached the end of the FAX call.

Apply T.30 transmit processing to generate a block of audio samples.

Parameters

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

Returns: The number of samples actually generated. This will be zero when there is nothing to send.

Process a block of received FSK modem audio samples.

Parameters

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

Returns: The number of samples unprocessed.

Fake processing of a missing block of received FSK modem audio samples (e.g due to packet loss).

Parameters

s	The modem context.
len	The number of samples to fake.

Returns: The number of samples unprocessed.

Parameters

s	A pointer to an HDLC transmitter context.

Returns: The next byte for transmission.

Parameters

s	A pointer to an HDLC transmitter context.
buf	The buffer for the data.
max_len	The number of bytes to get.

Returns: The number of bytes actually got.

Parameters

s	The context.
amp	An array of signal samples.
len	The number of samples in the array.

Returns: The number of unprocessed samples.

A dummy routine to use as a receive callback, when we aren't really trying to process what is received. It just absorbs and ignores the data.

Parameters

user_data	The context.
amp	The signal.buffer
len	The length of the signal buffer

Returns: 0.

A dummy routine to use as a receive fillin callback, when we aren't really trying to process what is received. It just absorbs and ignores the request.

Parameters

user_data	The context.
len	The length of the signal buffer

Returns: 0.

Fake processing of a missing block of received T.31 modem audio samples (e.g due to packet loss).

Parameters

s	The T.31 modem context.
len	The number of samples to fake.

Returns: The number of samples unprocessed.

Generate a block of T.31 modem audio samples.

Parameters

s	The T.31 modem context.
amp	The audio sample buffer.
max_len	The number of samples to be generated.

Returns: The number of samples actually generated.

Parameters

s	The T.38 context.
buf	The packet contents.
len	The length of the packet contents.
seq_no	The packet sequence number, used for logging purposes.

Returns: The length of the packet processed, or -1 if there is an error in the packet, or too few bytes of data to complete it.

Apply fake processing when a block of audio samples is missing (e.g due to packet loss).

Parameters

s	The T.38 context.
len	The number of samples to fake.

Returns: The number of samples unprocessed. This should only be non-zero if the software has reached the end of the FAX call.

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.

Fake processing of a missing block of received V.17 modem audio samples. (e.g due to packet loss).

Parameters

s	The modem context.
len	The number of samples to fake.

Returns: The number of samples unprocessed.

Process a block of received V.18 audio samples.

Parameters

s	The V.18 context.
amp	The audio sample buffer.
len	The number of samples in the buffer.

Fake processing of a missing block of received V.22bis modem audio samples. (e.g due to packet loss).

Parameters

s	The modem context.
len	The number of samples to fake.

Returns: The number of samples unprocessed.

Generate a block of V.22bis modem audio samples.

Parameters

s	The modem context.
amp	The audio sample buffer.
len	The number of samples to be generated.

Returns: The number of samples actually generated.

Fake processing of a missing block of received V.27ter modem audio samples. (e.g due to packet loss).

Parameters

s	The modem context.
len	The number of samples to fake.

Returns: The number of samples unprocessed.

Fake processing of a missing block of received V.29 modem audio samples. (e.g due to packet loss).

Parameters

s	The modem context.
len	The number of samples to fake.

Returns: The number of samples unprocessed.

Process a block of received V.8 audio samples.

Parameters

s	The V.8 context.
amp	The audio sample buffer.
len	The number of samples in the buffer.

Get the next bit of a transmitted serial bit stream.

Apply T.30 transmit processing to generate a block of audio samples.

Apply fake T.30 receive processing.

Apply T.30 receive processing to a block of audio samples.

Parameters

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

Returns: The number of samples unprocessed. This should only be non-zero if the software has reached the end of the FAX call.

Apply fake T.30 receive processing when a block of audio samples is missing (e.g due to packet loss).

Parameters

s	The FAX context.
len	The number of samples to fake.

Returns: The number of samples unprocessed. This should only be non-zero if the software has reached the end of the FAX call.

Apply T.30 transmit processing to generate a block of audio samples.

Parameters

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

Returns: The number of samples actually generated. This will be zero when there is nothing to send.

◆ SPAN_DECLARE_NONSTD() [2/2]

SPAN_DECLARE_NONSTD ( void )

Put a single bit of data to an HDLC receiver.

Put a series of bytes of data to an HDLC receiver.

Put a byte of data to an HDLC receiver.

Parameters

s	A pointer to an HDLC receiver context.
new_bit	The bit.
s	A pointer to an HDLC receiver context.
new_byte	The byte of data.
s	A pointer to an HDLC receiver context.
buf	The buffer of data.
len	The length of the data in the buffer.

Classes

Macros

Typedefs

Functions

Variables

Macro Definition Documentation

◆ HDLC_MAXFRAME_LEN

Typedef Documentation

◆ hdlc_rx_state_t

◆ hdlc_tx_state_t

Function Documentation

◆ hdlc_rx_free()

◆ hdlc_rx_get_stats()

◆ hdlc_rx_init()

◆ hdlc_rx_release()

◆ hdlc_rx_restart()

◆ hdlc_rx_set_frame_handler()

◆ hdlc_rx_set_max_frame_len()

◆ hdlc_rx_set_octet_counting_report_interval()

◆ hdlc_rx_set_status_handler()

◆ hdlc_tx_abort()

◆ hdlc_tx_corrupt_frame()

◆ hdlc_tx_flags()

◆ hdlc_tx_frame()

◆ hdlc_tx_free()

◆ hdlc_tx_init()

◆ hdlc_tx_release()

◆ hdlc_tx_restart()

◆ hdlc_tx_set_max_frame_len()

◆ SPAN_DECLARE_NONSTD() [1/2]

◆ SPAN_DECLARE_NONSTD() [2/2]