#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <getopt.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip.h>

struct _entry {
	u_int16_t gameid;
	u_int32_t ip;
	u_int16_t port1;
	u_int16_t port2;
} __attribute__ ((packed));

static char hlswheader[] = "\xFF\xFF\xFF\xFFHLSWLANSEARCH";

static char *id2name[] = {
	"Unknown", // 0 
	"Halflife",
	"Quake 1",
	"Quake 2",
	"Q3Comp",
	"Unreal Tournament",
	"Quake 3 Arena",
	"Elite Force",
	"Return to Castle Wolfenstein",
	"GSProt",
	"Command & Conquer Renegade", // 10
	"Medal of Honor: Allied Assault",
	"Jedi Knight 2",
	"Soldier of Fortune",
	"Unreal Tournament 2003",
	"America's Army: Operations",
	"Battlefield 1942",
	"Alien vs. Predator 2",
	"Rune",
	"Project IGI2: Covert Strike",
	"Never Winter Nights", // 20
	"Medal of Honor: Allied Assault Spearhead",
	"Operation Flashpoint",
	"Operation Flashpoint Resistance",
	"Devastation",
	"Wolfenstein - Enemy Territory",
	"Elite Force 2",
	"Jedi Knight 3",
	"Medal of Honor: Allied Assault Breakthrough",
	"Tribes 2",
	"Halo", // 30
	"Call of Duty", 
	"Savage: The Battle for Newerth",
	"Unreal Tournament 2004",
	"HLSteam",
	"Battlefield Vietnam",
	"GS2Prot",
	"Pain Killer",
	"Doom 3",
	"OGPProt",
	"Halflife 2", // 40
	"Tribes Vengeance",
	"Call of Duty: United Offensive"
};

static struct option opts[] = {
	{"destination",	1, 0, 'd'},
	{"intervall",	1, 0, 'i'},
	{"help",	0, 0, 'h'},
	{0, 0, 0, 0}
};

static int sock;

static void parse_pkt(struct sockaddr_in *src, void *pkt, unsigned int size) {
	struct _entry *server;
	struct in_addr tmp;

	if (size < sizeof(hlswheader) || strncmp(pkt, hlswheader, sizeof(hlswheader))) {
		printf("received INVALID packet from: %15s:%-5d  size=%d\n",
			inet_ntoa(src->sin_addr), ntohs(src->sin_port), size);

	} else {
		printf("received hlsw packet from: %15s:%-5d  size=%d\n",
			inet_ntoa(src->sin_addr), ntohs(src->sin_port), size);
	
		server = pkt + sizeof(hlswheader);
		while ((void *)server < pkt + size) {
			tmp.s_addr = server->ip;
			printf("  ip=%15s port1=%5d port2=%5d gameid=%2d (%s)\n",
				inet_ntoa(tmp), server->port1, server->port2,
				server->gameid, id2name[server->gameid]);
			server++;
		}
	}
}

static int scan_init() {
	int i = 1;
	
	if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
		perror("socket()");
		return -1;
	}

	if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &i, sizeof(i))) {
		perror("setsockopt()");
		return -1;
	}
	
	return 0;
}

static int scan_transmit(struct sockaddr_in *dst) {
	if (sendto(sock, hlswheader, sizeof(hlswheader), 0, (struct sockaddr *)dst, sizeof(struct sockaddr_in)) < 0) {
		perror("sendto()");
		return -1;
	}

	return 0;
}

static int scan_receive() {
	struct sockaddr_in src;
	struct timeval tv;
	fd_set fdsel;
	unsigned int i = 1, recvsize;
	void *pkt;

	FD_ZERO(&fdsel);
	FD_SET(sock, &fdsel);
	
	tv.tv_sec = 1;
	tv.tv_usec = 0;
	
	while (1) {
		if (select(FD_SETSIZE, &fdsel, NULL, NULL, &tv) < 0) {
			perror("select");
			return -1;
		}

		/* timeout: our exit */
		if (tv.tv_sec == 0 && tv.tv_usec == 0)
			break;
		
		/* get packetsize */
		if (ioctl(sock, FIONREAD, &recvsize) == -1) {
			perror("ioctl");
			return -1;
		}
		
		if (recvsize > 0) {
			if (!(pkt = malloc(recvsize))) {
				perror("malloc()");
				return -1;
			}

			i = sizeof(struct sockaddr_in);
			recvsize = recvfrom(sock, pkt, recvsize, 0, (struct sockaddr *)&src, &i);

			parse_pkt(&src, pkt, recvsize);

			free(pkt);
		}
	}

	return 0;
}

int main(int argc, char *argv[]) {
	struct sockaddr_in dst;
	int arg = 0, code = 0;
	int freq = -1;

	dst.sin_family = AF_INET;
	dst.sin_port = htons(7140);
	inet_aton("255.255.255.255", &dst.sin_addr);

	while (code != -1) {
		code = getopt_long(argc, argv, "d:i:h", opts, &arg);

		switch (code) {
		case 'd':	/* destination */
				if (inet_pton(dst.sin_family, optarg, &dst.sin_addr) <= 0) {
					fprintf(stderr, "invalid destination: %s\n", optarg);
					exit(-1);
				}
				break;
				
		case 'i':	/* intervall */
				freq = atoi(optarg);
				if (freq < 1) {
					fprintf(stderr, "invalid interval: %s\n", optarg);
					exit(-1);
				}
				break;

		case 'h':	/* help */
				printf("Usage: masterquery [options]\n"
					"Options: \n"
					"  --destination   -d   scan destination <ip>\n"
					"  --intervall     -i   scan intervall in seconds\n"
					"  --help          -h   this help\n"
					"\n");
				exit(0);
				break;

		case '?':	/* error */
				exit(-1);
				break;

		default:	/* unknown / all options parsed */
				break;
		}
	}

	if (scan_init())
		exit(-1);

	while (1) {
		if (scan_transmit(&dst))
			exit(-1);

		if (scan_receive())
			exit(-1);

		if (freq < 0)
			break;
		
		sleep(freq -1);
	}

	close(sock);
	return 0;
}