// Florea Alexandru - Ionut

// 323CA

// Tema1 - PC

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <time.h>

#include "lib.h"

#define HOST "127.0.0.1"

#define PORT 10000

// fucntie care returneaza data si ora curenta

char* currentDateTime(char* str) {

time_t now = time(0);

struct tm tstruct;

char buf[80];

tstruct = *localtime(&now);

strftime(buf, sizeof(buf), "[%d-%m-%Y %X] ", &tstruct);

strcpy(str, &buf[0]);

return str;

}

// functie pentru transformarea unui octet intr-un sir format din valoarea sa

// in binar

char *byte_to_binary(unsigned char x)

{

static char b[9];

b[0] = '\0';

int z;

for (z = 128; z > 0; z >>= 1)

{

strcat(b, ((x & z) == z) ? "1" : "0");

}

return b;

}

// functie pentru determinarea checksumu-ului unui sir de octeti prin

//efectuarea operatiei xor intre ei

unsigned char get_checksum(msg m)

{

unsigned char checksum = m.data[0];

int i;

for (i = 1; i < m.len; i ++)

{

checksum ^= m.data[i];

}

return checksum;

}

int main(int argc, char** argv){

init(HOST,PORT);

msg m1, *m2;

frame f;

//fisierul de log

FILE* log_file;

log_file = fopen ("log.txt","w");

fclose(log_file);

// fisierul de intrare

int in = open(argv[1], O_RDONLY);

lseek(in, 0, SEEK_SET);

struct stat s;

fstat (in, &s);

int file_size = (int) s.st_size;

unsigned char checksum;

int got_correct_ack = 1;

int size;

unsigned char nr_frame = 0;

char str[80];

while (file_size != 0)

{

log_file = fopen ("log.txt","a");

// daca s-a primit ACK corect se intra pe aceasta ramura

if (got_correct_ack)

{

// se trimite marimea fisierului de intrare, am considerat acest

// mesaj ca fiind un caz separat

if (nr_frame == 0)

{

m1.len = sizeof(int);

f.payload = malloc(sizeof(int));

memcpy(&m1.data[0], &nr_frame, 1);

sprintf(&m1.data[1],"%d", file_size);

sprintf((char*)f.payload,"%d", file_size);

checksum = get_checksum(m1);

memcpy(&m1.data[5], &checksum, 1);

send_message(&m1);

char to_binary[9];

strcpy(to_binary, byte_to_binary(checksum));

fprintf (log_file, "%s", currentDateTime(str));

fprintf(log_file, "[%s] Am trimis pachetul cu:\n\tSeq no:"

"%d\n\tPayload: %s\n\tChecksum: %s\n", argv[0], 0,

f.payload, to_binary);

fprintf(log_file,"------------------------------------------"

"-----------------------------------------------------\n");

}

// daca a fost trimisa marimea fisierului atunci se intra numai pe

// aceasta ramura

else

{

int payload_size = (rand() % (60 + 1 - 1)) + 1;

if (file_size <= payload_size)

{

payload_size = file_size;

f.payload = malloc(payload_size);

read(in, f.payload, file_size);

}

else

{

f.payload = malloc(payload_size);

read(in, f.payload, payload_size);

}

m1.len = payload_size;

size = m1.len;

memcpy(&m1.data[0], &nr_frame, 1);

memcpy (&m1.data[1], &f.payload[0], payload_size);

checksum = get_checksum(m1);

memcpy(&m1.data[1 + payload_size], &checksum, 1);

send_message(&m1);

char to_binary[9];

strcpy(to_binary, byte_to_binary(checksum));

fprintf (log_file, "%s", currentDateTime(str));

fprintf(log_file, "[%s] Am trimis pachetul cu:\n\tSeq no:"

"%d\n\tPayload: %s\n\tChecksum: %s\n", argv[0],

nr_frame, f.payload, to_binary);

fprintf(log_file,"------------------------------------------"

"-----------------------------------------------------\n");

}

}

// daca nu s-a primit ACK corect se retrimite ultimul pachet

else

{

send_message(&m1);

}

// verific daca s-a primit timeout

if ((m2 = receive_message_timeout(50)) == NULL)

{

got_correct_ack = 0;

fprintf (log_file, "%s", currentDateTime(str));

fprintf(log_file, "[%s] Am primit timeout, retrimit pachetul"

"cu no_seq: %d\n", argv[0], nr_frame);

fprintf(log_file,"------------------------------------------"

"-----------------------------------------------------\n");

fflush(log_file);

}

// daca nu s-a primit timeout verific daca s-a primit ACK corect

else

{

memcpy(&f.no_seq, m2->data, 1);

memcpy(&f.checksum, m2->data + 1, 1);

if (f.no_seq == f.checksum)

{

fprintf (log_file, "%s", currentDateTime(str));

fprintf(log_file, "[%s] Am primit ACK corect pentru "

"pachetul cu no_seq: %d, trimit urmatorul pachet\n",

argv[0], nr_frame);

fprintf(log_file,"------------------------------------------"

"-----------------------------------------------------\n");

fclose(log_file);

got_correct_ack = 1;

file_size -= size;

nr_frame ++;

free(f.payload);

}

else

{

fprintf (log_file, "%s", currentDateTime(str));

fprintf(log_file, "[%s] Am primit ACK gresit, retrimit "

"pachetul cu no_seq: %d", argv[0], nr_frame);

fprintf(log_file,"------------------------------------------"

"-----------------------------------------------------\n");

fclose(log_file);

got_correct_ack = 0;

}

}

}

log_file = fopen ("log.txt","a");

fprintf (log_file, "%s", currentDateTime(str));

fprintf(log_file, "[%s] Am trimis tot fisierul %s\n", argv[0], argv[1]);

fclose(log_file);

return 0;

}