/***************************************************************************
 *   Copyright (C) 04/2005 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <string.h>
#include "plugin_helper.h"

struct net_entry {
	struct in_addr ip;
	struct in_addr mask;
};

static struct net_entry *net_arr = NULL;
static int net_arr_size = 0;

static struct scan_ports port_arr[] = {
	{ 27015, 27024,  1 }, /* cs/hl */
	{ 0, 0, 0 }
};

static char scanmsg1[] = "\xff\xff\xff\xff" "details";
static char scanmsg2[] = "\xff\xff\xff\xff\x54";
static char scanmsg3[] = "\xff\xff\xff\xff" "TSource Engine Query";

static int scan(void)
{
	pkt_send_portarr(NULL, port_arr, scanmsg1, strlen(scanmsg1));
	pkt_send_portarr(NULL, port_arr, scanmsg2, strlen(scanmsg2));
	pkt_send_portarr(NULL, port_arr, scanmsg3, strlen(scanmsg3));
	return 1;
}

static int parse(struct net_pkt *pkt)
{
	struct in_addr tmp;
	int port, count, pos, i;

	if (!pkt_check_portarr(pkt, port_arr))
		return PARSE_REJECT;

	// check 0xFF 0xFF 0xFF 0xFF
	if (pkt_memcmp(pkt, 0, scanmsg1, 4))
		return PARSE_REJECT;

	/* check for short answer without ip/port */
	if (pkt->size >= 5 && pkt->buf[4] == 'm' && pkt->buf[5] == 0x00) {
		server_add_pkt(1, pkt);
		return PARSE_ACCEPT;
	}
	
	/* second query?! */
	if (pkt->size >= 5 && pkt->buf[4] == 'I' && pkt->buf[5] == 0x07) {
		server_add_pkt(40, pkt);
		return PARSE_ACCEPT;
	}
	
	/* parse server IP */
	pos = 5;
	if ((count = pkt_parse_ip(pkt, pos, &tmp)) == 0)
		return PARSE_REJECT;

	/* parse server port */
	pos += count +1;
	if ((count = pkt_parse_int(pkt, pos, &port)) == 0)
		return PARSE_REJECT;

	/* check server IP */
	for (i = 0; i < net_arr_size; i++) {
		if (((net_arr[i].ip.s_addr ^ tmp.s_addr) & net_arr[i].mask.s_addr) == 0) {
			server_add(1, tmp.s_addr, port, 0);
			return PARSE_ACCEPT;
		}
	}

	server_add(1, pkt->addr.sin_addr.s_addr, port, 0);
	return PARSE_ACCEPT;
}

static int parse_net(char *buf, struct net_entry *net)
{
	char *p;
	
	/* valid_net x.x.x.x */
	if ((p = strchr(buf, '/')) == NULL) {
		/* ip */
		if (inet_pton(AF_INET, buf, &net->ip) <= 0)
			return 0;

		/* mask */
		net->mask.s_addr = 0xFFFFFFFF;
		return 1;
		
	/* valid_net x.x.x.x/x.x.x.x oder x.x.x.x/xx */
	} else {
		int retval, mask;
		*p = 0x00;
		
		/* ip */
		if (inet_pton(AF_INET, buf, &net->ip) <= 0) {
			retval = 0;

		/* x.x.x.x/x.x.x.x */
		} else if (inet_pton(AF_INET, p+1, &net->mask) > 0) {
			retval = 1;
		
		/* x.x.x.x/xx */
		} else {
			mask = atoi(p+1);
			
			if (mask >= 0 && mask <= 32) {
				net->mask.s_addr = htonl(0xFFFFFFFF << (32 - mask));
				retval = 1;

			} else {
				retval = 0;
			}
		}
		
		*p = '/';
		return retval;
	}
}

static int init(struct conf_section *section)
{
	struct conf_tupel *tupel;
	static char buf[32];
	int i = 0, j;
	
	list_for_each_entry(tupel, &section->tupel, list)
		if (!strcmp(tupel->option, "valid_net"))
			i++;
			
	if (i == 0 || !(net_arr = malloc(sizeof(struct net_entry) * i)))
		return 0;

	i = 0;
	list_for_each_entry(tupel, &section->tupel, list) {
		if (strcmp(tupel->option, "valid_net"))
			continue;
			
		if (parse_net(tupel->parameter, &net_arr[i])) {
			j = sprintf(buf, " adding: %s", inet_ntoa(net_arr[i].ip));
			sprintf(buf + j, "/%s", inet_ntoa(net_arr[i].mask));
			log_print(buf);
			i++;
		} else {
			log_print(" invalid net: %s", tupel->parameter);
		}
	}
	net_arr_size = i;
	return 1;
}

static int fini()
{
	if (net_arr_size > 0 && net_arr)
		free(net_arr);
}

struct hlswmaster_plugin plugin = {
	.name		= "halflife",
	.scan		= &scan,
	.parse		= &parse,
	.init		= &init,
	.fini		= &fini,
};