bcast/net.c

#include "net.h"

int initNetwork() {
	// Load in Windows' socket networking support
	#if defined(WIN32)
		WORD wVersionRequested;
		WSADATA wsaData;
		int err;
		/* Use the MAKEWORD(lowbyte, highbyte) macro declared in Windef.h */
		wVersionRequested = MAKEWORD(2, 2);
		err = WSAStartup(wVersionRequested, &wsaData);
		if (err != 0) {
			/* Tell the user that we could not find a usable */
			/* Winsock DLL.                                  */
			printf("WSAStartup failed with error: %d\n", err);
		}
	#endif

	// @@TODO: move port initialization elswhere
	setConfig("port", "7332");

  // Get the env USER and hostname then build user@hostname nickname
	char *username = getenv("USER");
	char hostname[15]; // cap hostname to 16 chars, I guess
	gethostname(hostname, 16);
	size_t nick_length = strlen(hostname)+strlen(username)+1;
	char nick[nick_length];
	int i = 0;
	int j = 0;
	while(j<strlen(username)) {
		nick[i++] = username[j++];
	}
	nick[i++] = '@';
	j = 0;
	while(j<strlen(hostname)) {
		nick[i++] = hostname[j++];
	}
	nick[i] = '\0';
	setConfig("nick", nick);
	return 0;
}

int openListenSocket() {
	int ip_hash = generateHash("ip", CONFIG_HASH_SIZE);
	int port_hash = generateHash("port", CONFIG_HASH_SIZE);
	setAttribute(MAGENTA);
	setAttribute(UNDERSCORE);
	printf("--openListenSocket--\n");
	clearAttributes();
	setAttribute(GREEN);
	printf("IP: %s\n", config[ip_hash]);
	printf("port: %s\n", config[port_hash]);
	clearAttributes();
	printf("open: ");
	// Create our IPv4 datagram socket
	listen_socket = socket(AF_INET, SOCK_DGRAM, 0);
	if (listen_socket < 0) {
		perror("error");
		return -1;
	} else {
		printf("success\n");
	}
	// Allow the socket to be reusable
	int reuse = 1;
	printf("SO_REUSEADDR set: ");
	if (setsockopt(listen_socket, SOL_SOCKET, SO_REUSEADDR, (char*)&reuse, sizeof(reuse)) < 0) {
		perror("error");
		return -2;
	} else {
		printf("success\n");
	}
	// Join the broadcast group for 226.1.1.1
	if (!is_group_socket_set) {
		memset((char *) &group_socket, 0, sizeof(group_socket));
		group_socket.sin_family = AF_INET;
		//group_socket.sin_port = htons(7332);
		group_socket.sin_port = htons((unsigned short)strtoul(config[port_hash], NULL, 0));
		group_socket.sin_addr.s_addr = inet_addr("226.1.1.1");
		is_group_socket_set = 1;
	}
	// Bind to the socket w/ our group information
	printf("bind: ");
	if (bind(listen_socket, (struct sockaddr*)&group_socket, sizeof(group_socket))) {
		perror("error");
		return -3;
	} else {
		printf("success\n");
	}

	// join our group to user's selected IP
	group.imr_multiaddr.s_addr = inet_addr("226.1.1.1");
	group.imr_interface.s_addr = inet_addr(config[ip_hash]);
	printf("IP_ADD_MEMBERSHIP: ");
	if (setsockopt(listen_socket, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&group, sizeof(group)) < 0) {
		perror("error");
		return -4;
	} else {
		printf("success\n");
	}

	// TODO: move this
	is_listening = 1;
	/* add to master_fds? */
	listen_tv.tv_sec=0;
	listen_tv.tv_usec=0;
	//FD_ZERO(&master_fds);
	FD_SET(listen_socket, &master_fds);
	max_fd = listen_socket;
	return 0;
};

int closeListenSocket() {
	max_fd--;
	close(listen_socket);
	is_listening = 0;
	printf("closed listen_socket\n");
	return 0;
}

int openSendSocket() {
	int ip_hash = generateHash("ip", CONFIG_HASH_SIZE);
	int port_hash = generateHash("port", CONFIG_HASH_SIZE);
	setAttribute(MAGENTA);
	setAttribute(UNDERSCORE);
	printf("--openSendSocket--\n");
	clearAttributes();
	setAttribute(GREEN);
	printf("IP: %s\n", config[ip_hash]);
	printf("port: %s\n", config[port_hash]);
	clearAttributes();
	printf("open: ");
	send_socket = socket(PF_INET, SOCK_DGRAM, 0);
	if (send_socket < 0) {
		perror("error");
		return -1;
	} else {
		printf("success\n");
	}

	// FIXME: doesn't actually disable? :S
	printf("disable loopback: ");
	char loopback_char = 0;
	if (setsockopt(send_socket, IPPROTO_IP, IP_MULTICAST_LOOP, (char *)&loopback_char, sizeof(loopback_char)) < 0) {
		perror("error");
		return -2;
	} else {
		printf("success\n");
	}

	local_interface.s_addr = inet_addr(config[ip_hash]);
	//local_interface.s_addr = inet_addr("192.168.182.51");
	printf("local_interface set (%s): ", inet_ntoa(local_interface));
	if (setsockopt(send_socket, IPPROTO_IP, IP_MULTICAST_IF, (char *)&local_interface, sizeof(local_interface)) < 0) {
		perror("error:");
		return -3;
	} else {
		printf("success\n");
	}

	/* init sockaddr */

	if (!is_group_socket_set) {
		memset((char *) &group_socket, 0, sizeof(group_socket));
		group_socket.sin_family = PF_INET;
		group_socket.sin_addr.s_addr = inet_addr("226.1.1.1");
		//group_socket.sin_port = htons(7332);
		group_socket.sin_port = htons((unsigned short)strtoul(config[port_hash], NULL, 0));
		is_group_socket_set = 1;
	}
	is_sending = 1;
	return 0;
}

int closeSendSocket() {
	close(send_socket);
	is_sending = 0;
	printf("closed send_socket\n");
	return 0;
}

int setString(char *destination, const char source[]) {
	size_t len = strlen(source);
	size_t i = 0;
	while (source[i] != '\n' && i < len) {
		destination[i] = source[i];
		i++;
	}
	destination[len] = '\0';
	return 0;
}

char *stripString(const char string[]) {
	char *result = malloc(15);
	size_t len = strlen(string);
	size_t i = 0;
	char current_char = string[i];
	while (current_char != '\n' && current_char != '\0' && i < len) {
		result[i] = current_char;
		i++;
		current_char = string[i];
	}
	result[15] = '\0';
	return result;
}

void restartSockets(const char *value) {
	if (value) {
		if (!strcmp(value, START_LISTEN_COMMAND)) {
			if (is_listening) {
				stopListenSocket();
				startListenSocket();
			}
		} else if (!strcmp(value, START_SEND_COMMAND)) {
			if (is_listening) {
				stopSendSocket();
				startSendSocket();
			}
		}
	} else {
		if (is_listening) {
			stopListenSocket();
			startListenSocket();
		}
		if (is_listening) {
			stopSendSocket();
			startSendSocket();
		}
	}
}

void startSockets(const char *value) {
	if (value) {
		if (!strcmp(value, START_LISTEN_COMMAND)) {
			startListenSocket();
		} else if (!strcmp(value, START_SEND_COMMAND)) {
			startSendSocket();
		}
	} else {
			startListenSocket();
			startSendSocket();
	}
}

void stopSockets(const char *value) {
	if (value) {
		if (!strcmp(value, STOP_LISTEN_COMMAND)) {
			stopListenSocket();
		} else if (!strcmp(value, STOP_SEND_COMMAND)) {
			stopSendSocket();
		}
	} else {
			stopListenSocket();
			stopSendSocket();
	}
}

int startListenSocket() {
	if (!is_listening) {
		return (openListenSocket());
	} else {
		printf("already listening - 'stop' or 'restart' first\n");
	}
	return 0;
}
int stopListenSocket() {
	if (is_listening) {
		return (closeListenSocket());
	} else {
		printf("already stopped - 'start' first\n");
	}
	return 0;
}

int startSendSocket() {
	if (!is_sending) {
		return(openSendSocket());
	} else {
		printf("already sending - 'stop' or 'restart' first\n");
	}
	return 0;
}
int stopSendSocket() {
	if (is_sending) {
		return(closeSendSocket());
	} else {
		printf("already stopped - 'start' first\n");
	}
	return 0;
}

int handleOpenMessage(const char packet[]) {
	uint8_t nick_size;
	//uint8_t message_id;
	//uint8_t payload_type;
	uint8_t payload_size;

	int offset = 1; // skip past message_type
	nick_size = packet[offset++];
	char nick[nick_size];
	int j = 0;
	while(j < nick_size) {
		nick[j++] = packet[offset++];
	}
	//message_id = packet[offset++];
	offset++;
	//payload_type = packet[offset++];
	offset++;
	payload_size = packet[offset++];
	char payload[payload_size];
	j = 0;
	while(j < payload_size) {
		payload[j++] = packet[offset++];
	}

	printf("%s: %s", nick, payload);
	return 0;
}

void sendOpen(char buffer[]) {
	int packet_size = 0;
	// Build our packet's length in bytes first
	uint8_t message_type = MESSAGE_OPEN;
	packet_size++; // for message_type
	int nick_hash = generateHash("nick", CONFIG_HASH_SIZE);
	uint8_t nick_size = strlen(config[nick_hash])+1; // +1 for \0
	packet_size++; // for nick_length;
	packet_size += nick_size; // for nick itself
	uint8_t message_id = 9;
	packet_size++; // for message_id
	uint8_t payload_type = 1; // chat type
	packet_size++; // for payload type

	uint8_t buffer_size = strlen(buffer)+1;
	packet_size++; // for string_length char
	packet_size += buffer_size; // for payload itself
	//printf("packet size will be %d\n", packet_size);

	// Populate our packet
	int i = 0;
	int packet_offset = 0;
	char packet[packet_size];

	packet[packet_offset++] = message_type;
	packet[packet_offset++] = nick_size;

	while (i < nick_size) {
		packet[packet_offset++] = config[nick_hash][i++];
	}
	packet[packet_offset++] = message_id;
	packet[packet_offset++] = payload_type;
	packet[packet_offset++] = buffer_size;
	i = 0;
	while (i < buffer_size) {
		packet[packet_offset++] = buffer[i++];
	}
	receiveOpen(packet, DATAGRAM_SIZE);
	sendMulticast(send_socket, &group_socket, packet, packet_offset);
}

void receiveOpen(const char packet[], size_t packet_size) {
	if (packet[0] == MESSAGE_OPEN) {
		handleOpenMessage(packet);
	}
}

int sendMulticast(int send_socket, struct sockaddr_in *group_socket, char data_buffer[], int data_length) {
	if (sendto(send_socket, data_buffer, data_length, 0, (struct sockaddr*)group_socket, sizeof((*group_socket))) < 0) {
		perror("sendto error");
		return -1;
	}
	return 0;
}

// FIXME: interface list & IPs broken on OS X - perhaps due to IPV6 being active?
void getInterfaces() {
	int i;
	int test_socket = socket(AF_INET, SOCK_STREAM, 0);
	if (test_socket < 0) {
		return;
	}
	ifconf.ifc_buf = (char *) ifreq;
	// Set ifconf's ifc_len to the length of our array of interface ifreqs.
	ifconf.ifc_len = sizeof ifreq;
	//  Populate ifconf.ifc_buf (ifreq) with a list of interface names and addresses.
	if (ioctl(test_socket, SIOCGIFCONF, &ifconf) == -1)
		return;
	// Divide the length of the interface list by the size of each entry.
	// This gives us the number of interfaces on the system.
	interfaces = ifconf.ifc_len / sizeof(ifreq[0]);
	for (i = 0; i < interfaces; i++) {
		char ip[INET_ADDRSTRLEN];
		struct sockaddr_in *address = (struct sockaddr_in *) &ifreq[i].ifr_addr;
		// Convert the binary IP address into a readable string.
		if (!inet_ntop(AF_INET, &address->sin_addr, ip, sizeof(ip)))
			return;
		ip_list[i] = malloc(strlen(ip));
		setString(ip_list[i], ip);
		printf("%s - %s\n", ifreq[i].ifr_name, ip);
		dev_list[i] = malloc(strlen(ifreq[i].ifr_name));
		setString(dev_list[i], ifreq[i].ifr_name);
	}
	close(test_socket);
	setConfig("ip", ip_list[interfaces-1]);
}

void freeInterfaces() {
	int i;
	for (i = 0;i < interfaces;i++) {
		if (ip_list[i]) {
			free(ip_list[i]);
		}
	}
}