int llread(int fd,unsigned char* buffer) {
int num_chars_read = 0, aux_num_chars = 0;
int Type;
unsigned char aux[MAX_SIZE];
linkLayer.sequenceNumber = 0;
do {
Type= receiveframe(aux, &aux_num_chars);
if(Type == DATA_RECEIVED)
{
linkLayer.sequenceNumber = linkLayer.sequenceNumber ^ 1;
sendSupervisionFrame(linkLayer.fd, RR);
memcpy(buffer + num_chars_read, aux, aux_num_chars);
num_chars_read += aux_num_chars;
aux_num_chars = 0;
}
else if(Type == BAD_DATA_RECEIVED) {
rej_send_received++;
sendSupervisionFrame(linkLayer.fd, REJ);
}
else if(Type == DISC_RECEIVED) {
llclose(linkLayer.fd);
return num_chars_read;
}
} while(1);
return -1;
}
int llopen(int fd, int txrx) {
printf("[LLOPEN] START\n");
linkLayer.sequenceNumber = 0;
if(txrx == TRANSMITTER) {
int tmpvar;
(void) signal(SIGALRM, atende);
linkLayer.numTransmissions = 0;
linkLayer.timeout = MAXT;
printf("[llopen] Send SET\n");
sendSupervisionFrame(fd, SET);
alarm(linkLayer.timeout);
printf("[llopen] EXPETING UA\n");
tmpvar = receiveframe(NULL,NULL);
if( tmpvar != UA_RECEIVED ){
printf("[LLOPEN - TRANSMITTER] NOT UA\n");
return -1; //return error
}
else if(tmpvar == UA_RECEIVED) {
printf("[LLOPEN - TRANSMITTER] UA RECEIVED\n");
return fd; //retorn file ID
}
return -1;
}
else if (txrx == RECEIVER) {
printf("Waiting for SET\n");
if(receiveframe(NULL,NULL) == SET_RECEIVED) printf("SET_RECEIVED");
sendSupervisionFrame(fd,UA);
printf("UA sent\n");
return fd;
}
return 0;
}
int llopen(char* port, int txrx) {
int tmpvar;
linkLayer.fd = config(port);
linkLayer.State = txrx;
linkLayer.numTransmissions = 0;
linkLayer.timeout = MAXT;
linkLayer.frame = (unsigned char*) malloc((2*MAX_SIZE)+6);
linkLayer.alarm_char = SET;
linkLayer.alarm_inf = FALSE;
//printf("[RS-232] Port open - Starting");
if(txrx == TRANSMITTER) {
linkLayer.State = TRANSMITTER;
(void) signal(SIGALRM, Timeout);
sendSupervisionFrame(linkLayer.fd, SET);
alarm(linkLayer.timeout);
tmpvar = receiveframe(NULL,NULL);
if( tmpvar != UA_RECEIVED ) return -1; //return error
else if(tmpvar == UA_RECEIVED) {
(void) signal(SIGALRM, SIG_IGN);
return linkLayer.fd; //retorn file ID
}
return -1;
}
else if (txrx == RECEIVER) {
linkLayer.State = RECEIVER;
if(receiveframe(NULL,NULL) != SET_RECEIVED) {
return -1;
}
sendSupervisionFrame(linkLayer.fd,UA);
return linkLayer.fd;
}
return 1;
}
int llclose(int fd) {
int tmp;
(void) signal(SIGALRM, Timeout);
linkLayer.alarm_char = DISC;
if (linkLayer.State == TRANSMITTER) {
sendSupervisionFrame(fd, DISC);
alarm(linkLayer.timeout); //starting timout for DISC
tmp = receiveframe(NULL,NULL); //waiting for DISC
if (tmp == DISC_RECEIVED) {
(void) signal(SIGALRM, SIG_IGN); //closing Timeout if received
sendSupervisionFrame(fd, UA);
sleep(1);
close(fd);
return 1;
}
else{
return -1;
}
}
else if (linkLayer.State == RECEIVER) {
linkLayer.alarm_char = DISC;
sendSupervisionFrame(fd, DISC);
alarm(linkLayer.timeout); //starting timout for DISC
tmp = receiveframe(NULL,NULL);
if (tmp == UA_RECEIVED) {
(void) signal(SIGALRM, SIG_IGN); //closing Timeout if received
close(fd);
return 1;
}
else return -1;
}
else return -1;
}
int llread(int fd, char* buffer) {
printf("[LLREAD] START\n");
int num_chars_read = 0;
int Type = receiveframe(buffer, &num_chars_read);
if(Type == DATA_RECEIVED) {
printf("[LLREAD] END\n");
return num_chars_read;
}
return -1;
}
int write_frame(int fd, unsigned char* buffer, int length, int* i ,int remaning) {
(void) signal(SIGALRM, Timeout); //
//SENDING FRAME
if(remaning == FALSE) {
linkLayer.frameLength = MAX_SIZE;
memcpy(linkLayer.frame, buffer + (*i * MAX_SIZE), MAX_SIZE); //to be used by the timeout
sendInformationFrame(buffer + (*i * MAX_SIZE), MAX_SIZE);
}
else {
linkLayer.frameLength = length;
memcpy(linkLayer.frame, buffer + (*i * MAX_SIZE), length);
sendInformationFrame(buffer + (*i * MAX_SIZE), length);
}
//after sending frame switch sequence Number
alarm(linkLayer.timeout);
int tmp = receiveframe(NULL,NULL);
if(tmp != RR_RECEIVED) { //Bad RR being the oldest RR
*i = *i - 1;
(void) signal(SIGALRM, SIG_IGN);
if( (tmp == BAD_RR_RECEIVED) || (tmp = BAD_REJ_RECEIVED)) rej_send_received++;
else if(tmp == REJ_RECEIVED) rej_send_received++;
else return -1;
}
else if(tmp == RR_RECEIVED){
(void) signal(SIGALRM, SIG_IGN);
linkLayer.sequenceNumber = linkLayer.sequenceNumber^1;
}
linkLayer.numTransmissions = 0;
}
int llwrite(int fd, unsigned char* buffer, int length) {
printf("[LLWRITE] START\n");
linkLayer.timeout = 0;
int CompleteFrames = length / MAX_SIZE;
int remainingBytes = length % MAX_SIZE;
int flag = 1;
(void) signal(SIGALRM, atende);
linkLayer.numTransmissions = 0;
linkLayer.timeout = MAXT;
int i;
for(i = 0; i < CompleteFrames; i++){
flag = 1;
while(linkLayer.numTransmissions < MAXT && flag) {
printf("[LLWRITE] Frames = %d\n", i);
if(alarm_flag){
sendInformationFrame(buffer + (i * MAX_SIZE), MAX_SIZE);
alarm(linkLayer.timeout); // activa alarme de 3s
alarm_flag=0;
}
if(receiveframe(NULL,NULL) != RR_RECEIVED) {
if(receiveframe(NULL,NULL) == REJ_RECEIVED) linkLayer.numTransmissions = 0;
else return -1;
}
else if(receiveframe(NULL,NULL) == RR_RECEIVED) flag =0;
}
}
if(remainingBytes > 0){
printf("[LLWRITE] START\n");
flag = 1;
while(linkLayer.numTransmissions < MAXT && flag) {
if(alarm_flag){
sendInformationFrame(buffer + (i * MAX_SIZE), remainingBytes);
alarm(linkLayer.timeout); // activa alarme de 3s
alarm_flag=0;
}
if(receiveframe(NULL,NULL) != RR_RECEIVED) {
if(receiveframe(NULL,NULL) == REJ_RECEIVED) linkLayer.numTransmissions = 0;
else return -1;
}
else if(receiveframe(NULL,NULL) == RR_RECEIVED) flag =0;
}
}
printf("[LLWRITE] END\n");
return 0;
}
