Data_Connection_Protocol

Data Structures
struct	linkLayer
	Struct to hold information about the Link Layer. More...

Functions
int	llopen (int porta, int type)
	Opens a data connection with the serial port. More...
int	llwrite (int fd, char *buffer, int lenght)
	Writes the content of buffer to fd. More...
int	llread (int fd, unsigned char *buffer)
	Reads from fd to buffer. More...
int	llclose (int fd)
	Closes the connection to the serial port. More...

Variables
static struct sigaction	old_action
	sigaction to restore SIGALRN handler More...
int	testSend =0
struct linkLayer	linkLayer
	Data relative to the link layer. More...
struct termios	oldtio
	used in llclose to reset termios More...
volatile int	failed
	used in the alarm handler More...

Detailed Description

Function Documentation

llclose()

int llclose

(

int

fd

)

Closes the connection to the serial port.

Parameters

fd	data connection identifier

Returns

int positive value in case of sucess, -1 in case of error

References log_error(), log_success(), old_action, oldtio, RECEIVER, receiver_DISC_UA(), linkLayer::status, TRANSMITTER, and transmitter_DISC_UA().

Referenced by main().

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llopen()

int llopen	(	int	porta,
		int	type
	)

Opens a data connection with the serial port.

Parameters

porta	number of the port x in "/dev/ttySx"
type	TRANSMITTER|RECEIVER

Returns

int idata connection identifier or -1 in case of error

References atende(), initConnection(), log_error(), old_action, RECEIVER, receiver_UA(), linkLayer::status, TRANSMITTER, and transmitter_SET().

Referenced by main().

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llread()

int llread	(	int	fd,
		unsigned char *	buffer
	)

Reads from fd to buffer.

Parameters

fd	data connection identifier
buffer	character array of received data

Returns

int array's size or -1 in case of error

References A_ER, BCC, C_I, FLAG, log_error(), Read, readingCycle(), readR, linkLayer::sequenceNumber, Start, and stateMachineSetUp().

Referenced by receiverApp().

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llwrite()

int llwrite	(	int	fd,
		char *	buffer,
		int	lenght
	)

Writes the content of buffer to fd.

Parameters

fd	data connection identifier
buffer	character array of data to send
lenght	array's size

Returns

int amount of characters read or -1 in case of error

References A_ER, BCC, C_I, C_RR, fillFinalBuffer(), FLAG, log_error(), MAX_SIZE, linkLayer::sequenceNumber, Start, stateMachineSetUp(), Write, writeCycle(), and writeR.

Referenced by transmitterApp().

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Variable Documentation

failed

volatile int failed

used in the alarm handler

Referenced by atende(), transmitter_DISC_UA(), transmitter_SET(), and writeCycle().

linkLayer

struct linkLayer linkLayer

Data relative to the link layer.

old_action

struct sigaction old_action

static

sigaction to restore SIGALRN handler

Referenced by llclose(), and llopen().

oldtio

struct termios oldtio

used in llclose to reset termios

Referenced by initConnection(), and llclose().

testSend

int testSend =0