#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h> /* pid_t, socket(), bind(), listen(), accept() */

#include <sys/socket.h> /* socket(), bind(), listen(), accept() */

#include <arpa/inet.h> /* htonl(), htons() */

#include <string.h> /* memset() */

#include <unistd.h> /* fork(), read(), write() */

#include <signal.h>

#include <errno.h>

#include <time.h>

#include <sys/stat.h>

#include <netdb.h>

#define TES_PORT 59000

#define ECP_PORT 58055

#define MAX_BUF 128

#define NUM_OF_FILES 2

#define TES_NUMBER 1

#define ERR_SIZE 4

#define DEADLINE_MIN 1

//------------------------------------------------------

extern int errno;

const char * TOPIC_NAME = "Networks";

//-------------------------------------------------------

void handler_alrm(){

printf("Sockect timeout\n");

exit(1);

}

int checkdeadline(char*qid,struct tm *t ){

//N_N_DD_MM_YYYYY_HH_MM_SS

char* arr[10];

char * ch;

ch = strtok(qid, "_");

int i = 0;

while (ch != NULL) {

arr[i] = ch;

i++;

ch = strtok(NULL, "_");

}

if(t->tm_year +1900 > atoi(arr[4]))return -1;

if(t->tm_year +1900 == atoi(arr[4])) if(t->tm_mon +1 > atoi(arr[3]))return -1;

if(t->tm_mon +1 == atoi(arr[3])) if(t->tm_mday > atoi(arr[2]))return -1;

if(t->tm_mday == atoi(arr[2])) if(t->tm_hour > atoi(arr[5]))return -1;

if(t->tm_hour == atoi(arr[5])) if(t->tm_min > atoi(arr[6]))return -1;

if(t->tm_min == atoi(arr[6])) if(t->tm_sec > atoi(arr[7]))return -1;

return 0;

}

char* giveanswersfilename(char*qid){

//N_N_DD_MM_YYYYY_HH_MM_SS

char *filename=malloc(sizeof(char)* (13+1));

char* arr[10];

char * ch;

ch = strtok(strdup(qid), "_");

int i = 0;

while (ch != NULL) {

arr[i] = ch;

i++;

ch = strtok(NULL, "_");

}

sprintf(filename,"T%sQF%sA.txt",arr[0],arr[1]);

return filename;

}

struct tm* deadline(struct tm *t){

//deadline: current time + DEADLINE_MIN

if ((t->tm_min += DEADLINE_MIN) > 59) {

t->tm_min -= 60;

t->tm_hour++;

}

return t;

}

char* timeformat(struct tm *t) {

char *tf = malloc(sizeof(char)* (19));

strftime(tf, 19,"%d%b%Y_%H:%M:%S", t);

return tf;

}

char* timeformat1(struct tm *t) {

char *tf = malloc(sizeof(char)* (20));

strftime(tf, 20,"%d_%m_%Y_%H_%M_%S", t);

return tf;

}

char* createQID(char* SID, struct tm *t) {

char *QID = malloc(sizeof(char)* (23 + 1));

sprintf(QID,"%s%s", SID, timeformat(t));

return QID;

}

char* readTCPclient(int sockfd) {

char buffer[MAX_BUF];

int nread = 0;

int message_size = 0;

int i, message_capacity = MAX_BUF;

//allocates memory for an array of 1 element of BUFFER_SIZE bytes, and set to zero the allocated memory

char *message = calloc(1, sizeof(char) * MAX_BUF);

while ((nread = read(sockfd, buffer, MAX_BUF)) != 0) {

if(nread==-1) { //error

free(message);

exit(1);

}

for (i = 0; i < nread; i++) {

message[message_size + i] = buffer[i];

}

memset(buffer, 0, MAX_BUF);

message_size += nread;

if (message_size >= message_capacity) {

message_capacity += MAX_BUF;

message = realloc(message, message_capacity);

}

//message ends with the character '\n'

if(message[strlen(message)-1] == '\n')

break;

}

message[strlen(message) - 1] = '\0';

return message;

}

//--------------------------------------------------------------------------------------------

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

int fd_tcp, fd_ecp, newfd, clientlen, serverlen, ret, questionnaire_number, nbytes, nleft, size, score=0;

struct sockaddr_in serveraddr, clientaddr;

struct hostent *hostptr;

unsigned short int TESport = TES_PORT, ECPport = ECP_PORT;

ssize_t rcvd_bytes, send_bytes, read_file_bytes, send_bytes_data, AQT_bytes, AQS_bytes;

char *SID, *QID, dtime[18+1], *data, filename[12+1], *correctanswers, *ptr1, ECPname[MAX_BUF], recv_str[MAX_BUF], send_str[MAX_BUF];

SID = (char*)malloc(sizeof(char) * (5 + 1));

QID = (char*)malloc(sizeof(char) * (23 + 1));

char usage[] = "usage: ./TES [-p TESport] [-n ECPname] [-e ECPport]";

time_t rawtime;

struct tm * current_time;

time (&rawtime);

current_time = localtime (&rawtime);

pid_t pid;

void(*old_handler)(int);//interrupt handler

/* Avoid zombies when child processes die. */

if ((old_handler = signal(SIGCHLD, SIG_IGN)) == SIG_ERR) exit(1);

if (signal(SIGALRM, handler_alrm) == SIG_ERR) {

perror("Error in signal");

exit(1);

}

if (argc % 2 != 1 || argc > 7) {

printf("error: Incorrect number of arguments.\n%s\n", usage);

return 1;

}

if (argc == 3) {

if (!strcmp(argv[1], "-p")) TESport = atoi(argv[2]);

else if (!strcmp(argv[1], "-n")) strcpy(ECPname, argv[2]);

else if (!strcmp(argv[1], "-e")) ECPport = atoi(argv[2]);

else {

printf("error: Invalid option.\n%s\n", usage);

return 1;

}

}

if (argc == 5) {

if (!strcmp(argv[1], "-p")) {

TESport = atoi(argv[2]);

if (!strcmp(argv[3], "-n")) strcpy(ECPname, argv[4]);

else if (!strcmp(argv[3], "-e")) ECPport = atoi(argv[4]);

else {

printf("error: Invalid option.\n%s\n", usage);

return 1;

}

}

if (!strcmp(argv[1], "-n")) {

strcpy(ECPname, argv[2]);

if (!strcmp(argv[3], "-e")) ECPport = atoi(argv[4]);

else {

printf("error: Invalid option.\n%s\n", usage);

return 1;

}

}

else {

printf("error: Invalid option.\n%s\n", usage);

return 1;

}

}

if (argc == 7) {

if (!strcmp(argv[1], "-p")) {

TESport = atoi(argv[2]);

if (!strcmp(argv[3], "-n")) {

strcpy(ECPname, argv[4]);

if (!strcmp(argv[1], "-e")) ECPport = atoi(argv[2]);

else {

printf("error: Invalid option.\n%s\n", usage);

return 1;

}

}else {

printf("error: Invalid option.\n%s\n", usage);

return 1;

}

}else {

printf("error: Invalid option.\n%s\n", usage);

return 1;

}

}

if ((fd_tcp = socket(AF_INET, SOCK_STREAM, 0)) == -1) {

perror("Error creating tcp socket.\n");

exit(1);

}

if ((fd_ecp = socket(AF_INET, SOCK_DGRAM, 0)) == -1){

perror("Error creating ecp socket.\n");

exit(1);

}

memset((void*)&serveraddr, (int)'\0', sizeof(serveraddr));

serveraddr.sin_family = AF_INET;

serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);

serveraddr.sin_port = htons((u_short)TESport);

if (bind(fd_tcp, (struct sockaddr*)&serveraddr, sizeof(serveraddr)) == -1) {

perror("Error: bind().\n");

exit(1);

}

if (listen(fd_tcp, 5) == -1){

perror("Error: listen().\n");

exit(1);

}

while (1) {

clientlen = sizeof(clientaddr);

do newfd = accept(fd_tcp, (struct sockaddr*)&clientaddr, &clientlen);//wait for a connection

while (newfd == -1 && errno == EINTR);

if (newfd == -1){

perror("Error: accept().\n");

exit(1);

}

/* Create a child process for each new connection. */

if ((pid = fork()) == -1) {

perror("Error: fork().\n");

exit(1);

}

else if (pid == 0) { //child process

close(fd_tcp);

printf("Sent by [%s :%hu]\n",inet_ntoa(clientaddr.sin_addr),ntohs(clientaddr.sin_port));

/* USER-TES Protocol (in TCP) */

ptr1 = readTCPclient(newfd);

printf("\nReceived message:«%s»\n", ptr1);

//we can use parseString() from functions.c...

char* arr[8];

char * ch;

ch = strtok(strdup(ptr1), " ");

int i = 0;

while (ch != NULL) {

arr[i] = ch;

i++;

ch = strtok(NULL, " ");

}

/* USER-TES: RQT SID

TES-USER: AQT QID time size data */

if (strcmp(arr[0], "RQT") == 0 && atoi(arr[1]) < 100000 && atoi(arr[1]) > 9999) {

strcpy(SID, arr[1]);

questionnaire_number = rand() % (NUM_OF_FILES + 1);//choose randomly 1 of available questionnaires

sprintf(filename, "T%dQF%d.pdf", TES_NUMBER, questionnaire_number);

sprintf(dtime, "%s",timeformat(deadline(current_time)));

//generate QID: TES_NUMBER+questionnaire_number+deadline

sprintf(QID, "%d_%d_%s", TES_NUMBER, questionnaire_number, timeformat1(deadline(current_time)));

FILE *handler = fopen(filename, "rb");

if (handler == NULL){

perror("Error: fopen().\n");

exit(1);

}

fseek(handler, 0, SEEK_END);

size = ftell(handler);

rewind(handler);

//allocate a string that can hold it all

data = (char*)malloc(sizeof(char) * (size + 1));

//read it all in one operation

read_file_bytes = fread(data, sizeof(char), size, handler);

if (size != read_file_bytes) {

free(data);

perror("Error: fread().\n");

exit(1);

}

//each message ends with the character '\n'

AQT_bytes = sprintf(send_str, "AQT %s %s %d ", QID, dtime, size);

ptr1 = send_str;

/* write() may write a smaller number of bytes than solicited */

nleft = AQT_bytes + read_file_bytes; // '\0' is not transmitted

while (nleft > 0) {

if (nleft > read_file_bytes) {

send_bytes = write(newfd, ptr1, AQT_bytes);

if (send_bytes <= 0) {

perror("Error: write().\n");

exit(1);

}

nleft -= send_bytes;

ptr1 += send_bytes;

}

else {

send_bytes_data = write(newfd, data, nleft);

if (send_bytes_data <= 0) {

perror("Error: data write().\n");

exit(1);

}

nleft -= send_bytes_data;

data += send_bytes_data;

}

}

send_bytes_data = write(newfd, "\n", 1);

if (send_bytes_data <= 0) {

perror("Error: data write().\n");

exit(1);

}

close (newfd); exit(0);

}

else if (strcmp(arr[0], "RQS") == 0 ) {

if (atoi(arr[1]) > 99999 || atoi(arr[1]) < 10000 || sizeof(arr[2]) > 24){

if ((send_bytes = write(newfd, "-2\n", 4)) <= 0)exit(1);

close(newfd); exit(1);

}

strcpy(SID, arr[1]);

strcpy(QID, arr[2]);

if (checkdeadline(arr[2],current_time) == -1){

if ((send_bytes = write(newfd, "-1\n", 4)) <= 0)exit(1);

close(newfd); exit(1);

}

for (i = 0; i < 5; i++) {

if (strcmp(arr[i + 3], "A") == 0 ||

strcmp(arr[i + 3], "B") == 0 ||

strcmp(arr[i + 3], "C") == 0 ||

strcmp(arr[i + 3], "D") == 0 ||

strcmp(arr[i + 3], "N") == 0)continue;

else {

printf("\n----->invalid answers\n");

if ((send_bytes = write(newfd, "ERR\n", ERR_SIZE)) <= 0)exit(1);

}

}

FILE *a = fopen(giveanswersfilename(QID), "r");

if (a == NULL) {

perror("Error: fopen().\n");

exit(1);

}

fseek(a, 0, SEEK_END);

size = ftell(a);

rewind(a);

//allocate a string that can hold it all

correctanswers = (char*)malloc(sizeof(char) * (size));

//read it all in one operation

if (fread(correctanswers, sizeof(char), size, a) <= 0) {

perror("Error: fread().\n");

exit(1);

}

for (i = 0; i < 5; i++) {

if (*correctanswers == arr[i + 3][0]) {

score += 20;

correctanswers+=3;

}

}

AQS_bytes = sprintf(send_str, "AQS %s %d\n", QID, score);

ptr1 = send_str;

nbytes = AQS_bytes; // '\0' is not transmitted

/* write() may write a smaller number of bytes than solicited */

nleft = nbytes;

while (nleft > 0) {

send_bytes = write(newfd, ptr1, nleft);

if (send_bytes <= 0) exit(1); //error

nleft -= send_bytes;

ptr1 += send_bytes;

}

printf("TEST AQS sent : «%s»", send_str);

close(newfd);

/* TES-ECP Protocol (in UDP) */

memset((void*)&serveraddr, (int)'\0', sizeof(serveraddr));

serveraddr.sin_family = AF_INET;

if ((hostptr = gethostbyname(ECPname)) == NULL) exit(1);

printf("%s", ECPname);

serveraddr.sin_addr.s_addr = ((struct in_addr*)(hostptr->h_addr_list[0]))->s_addr; //ECP server IP address

printf("%s", hostptr->h_name);

serveraddr.sin_port = htons((u_short)ECPport);

serverlen = sizeof(serveraddr);

/* TES-ECP: IQR SID QID topic_name score

ECP-TES: AWI QID */

sprintf(send_str, "IQR %s %s %s %d\n", SID, QID, TOPIC_NAME, score);

printf("%s\n",send_str);

send_bytes = sendto(fd_ecp, send_str, strlen(send_str), 0, (struct sockaddr*)&serveraddr, serverlen);

if (send_bytes == -1)exit(1);//error

alarm(10);//generates the SIGALRM signal when the specified time has expired

rcvd_bytes = recvfrom(fd_ecp, recv_str, strlen(recv_str), 0, (struct sockaddr*)&clientaddr, &clientlen);

if (rcvd_bytes == -1)exit(1);//error

else alarm(0); //cancel currently active alarm

char *array[8];

char *c = strtok(recv_str, " ");

int j = 0;

while (c != NULL) {

array[j] = c;

j++;

c = strtok(NULL, " ");

}

if (strcmp(array[0], "AWI") == 0 && strcmp(array[1], QID) == 0) {

close(fd_ecp);

exit(0);

}

else {

send_bytes = sendto(fd_ecp, "ERR\n", ERR_SIZE, 0, (struct sockaddr*)&serveraddr, serverlen);

if (send_bytes == -1)exit(1);//error

exit(1);

}

}

else {

printf("\n----->invalid answers\n");

send_bytes = write(newfd, "ERR\n", ERR_SIZE);

if (send_bytes <= 0)exit(1);

close(newfd); exit(1);

}

}

//parent process

do ret = close(newfd);

while (ret == -1 && errno == EINTR);

if (ret == -1)exit(1);//error

}

}