hdlc.c File Reference

#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include "spandsp/telephony.h"
#include "spandsp/async.h"
#include "spandsp/crc.h"
#include "spandsp/bit_operations.h"
#include "spandsp/hdlc.h"

Functions

void hdlc_rx_put_bit (hdlc_rx_state_t *s, int new_bit)
 Put a single bit of data to an HDLC receiver.
void hdlc_rx_put_byte (hdlc_rx_state_t *s, int new_byte)
 Put a byte of data to an HDLC receiver.
void hdlc_rx_put (hdlc_rx_state_t *s, const uint8_t buf[], int len)
 Put a series of bytes of data to an HDLC receiver.
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.
hdlc_rx_state_thdlc_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_get_stats (hdlc_rx_state_t *s, hdlc_rx_stats_t *t)
 Get the current receive statistics.
int hdlc_tx_frame (hdlc_tx_state_t *s, const uint8_t *frame, size_t len)
 Transmit a frame.
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.
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_get_byte (hdlc_tx_state_t *s)
 Get the next byte for transmission.
int hdlc_tx_get_bit (hdlc_tx_state_t *s)
 Get the next bit for transmission.
int hdlc_tx_get (hdlc_tx_state_t *s, uint8_t buf[], size_t max_len)
 Get the next sequence of bytes for transmission.
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.
hdlc_tx_state_thdlc_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.

Detailed Description


Function Documentation

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.

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.

void hdlc_rx_put ( hdlc_rx_state_t s,
const uint8_t  buf[],
int  len 
)

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

Parameters:
s A pointer to an HDLC receiver context.
buf The buffer of data.
len The length of the data in the buffer.

void hdlc_rx_put_bit ( hdlc_rx_state_t s,
int  new_bit 
)

Put a single bit of data to an HDLC receiver.

Parameters:
s A pointer to an HDLC receiver context.
new_bit The bit.

void hdlc_rx_put_byte ( hdlc_rx_state_t s,
int  new_byte 
)

Put a byte of data to an HDLC receiver.

Parameters:
s A pointer to an HDLC receiver context.
new_byte The byte of data.

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.

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.

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.

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.

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.

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.

int hdlc_tx_get ( hdlc_tx_state_t s,
uint8_t  buf[],
size_t  max_len 
)

Get the next sequence of bytes for transmission.

Parameters:
s A pointer to an HDLC transmitter context.
buf The buffer for the data.
len The number of bytes to get.
Returns:
The number of bytes actually got.

int hdlc_tx_get_bit ( hdlc_tx_state_t s  ) 

Get the next bit for transmission.

Parameters:
s A pointer to an HDLC transmitter context.
Returns:
The next bit for transmission.

int hdlc_tx_get_byte ( hdlc_tx_state_t s  ) 

Get the next byte for transmission.

Parameters:
s A pointer to an HDLC transmitter context.
Returns:
The next byte for transmission.

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.

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.


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