Routing-Table-Manager/app/client.c

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/shm.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>

#include "dll.h"
#include "mac-list.h"
#include "routing-table.h"
#include "sync.h"

int data_socket;
int loop = 1; // indicates if server is still up and running
int disconnect = 1; // indicates to server that client wants to disconnect

/*
* Client's copies of network data structures.
*/
dll_t* routing_table;
dll_t* mac_list;

/* Break out of main infinite loop and inform server of intent to disconnect */

void signal_handler(int signal_num) {
	
	if (signal_num == SIGINT) {
		loop = 0;
		write(data_socket, &disconnect, sizeof(int));
		close(data_socket);
		deinit_dll(routing_table);
		deinit_dll(mac_list);
		exit(0);
	}
	else if (signal_num == SIGUSR1) {
		deinit_dll(routing_table);
		deinit_dll(mac_list);

		routing_table = init_dll();
		mac_list = init_dll();
	}

}

/*
* Optionally, display contents of a data
* structure (routing table or MAC list).
*/
void display_ds(int synchronized) {
	char c, flush;

	switch (synchronized) {
	case RT:

		printf("Routing table is up to date. Would you like to see it?(y/n)\n");
		c = getchar();

		scanf("%c", &flush);
		if (c == 'y') {
			display_routing_table(routing_table);
		}

		break;

	case ML:

		printf("MAC list is up to date. Would you like to see it?(y/n)\n");
		c = getchar();
		scanf("%c", &flush);
		if (c == 'y') {
			display_mac_list(mac_list);
		}
		break;

	default:

		break;
	}
}

int main() {

	struct sockaddr_un addr;

	routing_table = init_dll();
	mac_list = init_dll();

	data_socket = socket(AF_UNIX, SOCK_STREAM, 0);
	if (data_socket == -1) {
		perror("socket");
		exit(1);
	}

	memset(&addr, 0, sizeof(struct sockaddr_un));
	addr.sun_family = AF_UNIX;
	strncpy(addr.sun_path, SOCKET_NAME, sizeof(addr.sun_path) - 1);

	if (connect(data_socket, (const struct sockaddr*)&addr,
		sizeof(struct sockaddr_un)) == -1) {
		fprintf(stderr, "The server is down.\n");
		exit(1);
	}


	pid_t pid = getpid();

	write(data_socket, &pid, sizeof(pid_t)); // send server client's process id

	signal(SIGINT, signal_handler); // register signal handler.
	signal(SIGUSR1, signal_handler);
	/*
	* Continously wait for updates to routing table and MAC list
	* from the server regarding table contents and server state.
	*/

	while (loop) {
		int synchronized;
		char ip[IP_ADDR_LEN];

		sync_msg_t* sync_msg = calloc(1, sizeof(sync_msg_t));

		memset(ip, 0, IP_ADDR_LEN);

		if (read(data_socket, sync_msg, sizeof(sync_msg_t)) == -1) {
			perror("read");
			break;
		}

		if (read(data_socket, &synchronized, sizeof(int)) == -1) {
			perror("read");
			break;
		}

		if (read(data_socket, &loop, sizeof(int)) == -1) {
			perror("read");
			break;
		}

		if (sync_msg->l_code == L3) {
			process_sync_mesg(routing_table, sync_msg);
		}
		else {
			process_sync_mesg(mac_list, sync_msg);
		}

		display_ds(synchronized);
	}

	exit(0);
}