server.c

#include"chat.h"


void* connection_handler(void* socket);
void transmitt(int socket, int index);
int recv_uname(int socket);
int serv_auth(int socket, char* password);

int n = 0;
int clients[MAX_CLIENTS];
char usernames[MAX_CLIENTS][MAX_UNAME];
/*testing*/

char password[MAX_UNAME];
bool using_password;

struct sockaddr_in address;
int addrlen = sizeof(address);
pthread_mutex_t lock;

int main(int argc, char **argv)
{
	if(argc < 2){
		printf("Usage: server <port> [password]\n");
		return 0;
	}
	if(argc < 3){
		using_password = false;
		printf("WARNING: Starting server without password protection\n");
	}
	else{
		if(strlen(argv[2])<6){
			printf("Password too short, six charachters required\n");
			return 0;
		}
		using_password = true;
		strncpy(password, argv[2], sizeof(password));
		printf("Password: %s\n", password);
	}
	int sock, client, valread;
	int port = atoi(argv[1]);
	int opt = 1;
	pthread_t thread;
	pthread_t pool[MAX_THREADS];
	

	if((sock = socket(AF_INET, SOCK_STREAM, 0)) == 0){
		perror("SOCKET FAILED");
		exit(EXIT_FAILURE);
	}
	
	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT,&opt, sizeof(opt))) { 
        	perror("setsockopt"); 
        	exit(EXIT_FAILURE); 
         } 
	
	address.sin_family = AF_INET;
	address.sin_addr.s_addr = INADDR_ANY;
	address.sin_port = htons(port);
	
	if(bind(sock, (struct sockaddr *)&address, sizeof(address))<0){
		perror("BIND FAILED");
		exit(EXIT_FAILURE);
	}
	
	if(listen(sock, 3) < 0){
		perror("LISTEN FAILED");
		exit(EXIT_FAILURE);
	}
	
	printf("LISTENING ON PORT %d\n", port);
	pthread_mutex_init(&lock, NULL);
	for(int i=0;i<MAX_THREADS;i++){
	 	pthread_create(&pool[i], NULL, connection_handler, &sock);
	}
	for(int i =0;i<MAX_CLIENTS;i++){
		pthread_join(pool[i], NULL);	
	}
	return 0;
}

void* connection_handler(void* socket){
	int sock = *((int *)socket);
	int client;
	int index;
	while(1){	
		printf("THREAD: %x WAITING FOR CONNECTIONS\n", pthread_self);
		client = accept(sock, (struct sockaddr*)&address, (socklen_t*)&addrlen);
		pthread_mutex_lock(&lock);
		index = find_free(clients, MAX_CLIENTS);
		if(index < 0){
			printf("Client limit reached\n");
			pthread_mutex_unlock(&lock);
		}
		else{
			clients[index] = client;
			pthread_mutex_unlock(&lock);
			transmitt(client, index);
		}
	}
}


void transmitt(int socket, int index){
	printf("CONNECTION TO THREAD %x\n", pthread_self());
	char tmp[MAX];
	char bye[MAX];
	//char uname[MAX_UNAME];
	char buffer[MAX+MAX_UNAME];
	int uname_index = 0;
	int temp;
	sprintf(bye, "%d", BYE_MESSAGE);
	if((temp = serv_auth(socket, password))!=0){
		printf("strncmp result: %d\n", temp);
		snprintf(buffer, sizeof(buffer), "Incorrect password");
		if(send(socket, buffer, sizeof(buffer), 0)<0){
			printf("Failed to send error message\n");
		}
		printf("Auth failed\n");
		clients[index]=NULL;
		return;
	}

	if ((uname_index = recv_uname(socket)) < 0){
		printf("Failed to receive username. Disconnecting...\n");
		clients[index] = NULL;
		bzero(usernames[uname_index], sizeof(usernames[uname_index]));
		return;
	}

	while(1){
		bzero(tmp, sizeof(tmp));
		bzero(buffer, sizeof(buffer));
		if(recv(socket, tmp, sizeof(tmp), 0)<0){
			printf("Failed to receive message\n");			
			snprintf(buffer, sizeof(buffer), "Error: Failed tp receive message");
			if(send(socket, buffer, sizeof(buffer), 0)<0){
				printf("Failed to send error message. Disconnecting...\n");
				clients[index]=NULL;
				bzero(usernames[uname_index], sizeof(usernames[uname_index]));
				return;
			}
		}
		if(strncmp(bye, tmp, MAX) == 0){
			printf("THREAD: %x DISCONNECTED\n", pthread_self());
			snprintf(buffer, sizeof(buffer), "SERVER MESSAGE: %s HAS DISCONNECTED", usernames[uname_index]);
			for(int i =0;i<MAX_CLIENTS;i++){
				if(clients[i] != NULL){
					if(send(clients[i], buffer, sizeof(buffer), 0)<0){
						printf("Failed to send message to %d", clients[i]);
					}
				}
			}
			clients[index] = NULL;
			bzero(usernames[uname_index], sizeof(usernames[uname_index]));
			return;
		}
		snprintf(buffer, sizeof(buffer), "%s: %s", usernames[uname_index], tmp);
		for(int i =0;i<MAX_CLIENTS;i++){
			if(clients[i] != NULL){
				if(send(clients[i], buffer, sizeof(buffer), 0)<0){
					printf("Failed to send message to %d", clients[i]);
				}
			}
		}
		printf("%s\n", buffer);
	}
}

int recv_uname(int socket){
	char uname[MAX_UNAME];
	memset(uname, 0, sizeof(uname));
	char prompt[MAX_UNAME];
	int index = 0;
	char *un_arrp[MAX_UNAME];
	for (int i=0;i<MAX_CLIENTS;i++){
		un_arrp[i] = usernames[i];
	}

	snprintf(prompt, sizeof(prompt), "USERNAME: ");
	if(send(socket, prompt, sizeof(prompt), 0)<0){
		printf("Failed to send prompt message\n");
		return -1;
	}
	if(recv(socket, uname, MAX_UNAME, 0)<0){
		return -1;
	}

	pthread_mutex_lock(&lock);
	if(find_string_in_array(un_arrp, uname, MAX_CLIENTS)!=-1){
		snprintf(prompt, sizeof(prompt), "Username taken");
		if(send(socket, prompt, sizeof(prompt), 0)<0){
			printf("Failed to send error message\n");
		}
		pthread_mutex_unlock(&lock);
		return -1;
		}
	index = find_free((int*)usernames, MAX_CLIENTS);
	if(index < 0){
		printf("Client limit reached\n");
		pthread_mutex_unlock(&lock);
	}
	snprintf(usernames[index], sizeof(uname), "%s", uname);
	pthread_mutex_unlock(&lock);
	return index;
}
int serv_auth(int socket, char* passwd){
	size_t n = sizeof(passwd);
	char buffer[MAX_UNAME];
	if(!using_password){
		snprintf(buffer, sizeof(buffer), "NO PASS REQUIRED");
		if(send(socket, buffer, sizeof(buffer), 0)<0){
			printf("Failed to send prompt message\n");
			return -1;
		}
		if(recv(socket, buffer, sizeof(buffer), 0)<0){
			return -1;
		}
		return 0;
	}
	snprintf(buffer, sizeof(buffer), "SERVER PASSWORD: ");
	if(send(socket, buffer, sizeof(buffer), 0)<0){
		printf("Failed to send prompt message\n");
		return -1;
	}
	bzero(buffer, sizeof(buffer));
	if(recv(socket, buffer, sizeof(buffer), 0)<0){
		return -1;
	}
	printf("Auth attempt: %s\n", buffer);
	return strncmp(password, buffer, sizeof(buffer));

}