/*
 *
 * Copyright (c) 2011-2016 The University of Waikato, Hamilton, New Zealand.
 * All rights reserved.
 *
 * This file is part of libprotoident.
 *
 * This code has been developed by the University of Waikato WAND
 * research group. For further information please see http://www.wand.net.nz/
 *
 * libprotoident is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * libprotoident 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 */

#include <string.h>

#include "libprotoident.h"
#include "proto_manager.h"
#include "proto_common.h"

static inline bool match_dhcp_v4(lpi_data_t *data) {
	if (match_chars_either(data, 0x01, 0x01, 0x06, 0x00))
		return true;
	if (match_chars_either(data, 0x02, 0x01, 0x06, 0x00))
		return true;
	
	return false;
}

static inline bool match_dhcp_v6_ports(uint16_t porta, uint16_t portb) {
	if (porta == 547 && portb == 546)
		return true;
	if (portb == 547 && porta == 546)
		return true;
	return false;
}

static inline bool match_dhcp_v6_solicit(uint32_t payload, uint32_t len) {

	if (len < 52)
		return false;
	if (!MATCH(payload, 0x01, ANY, ANY, ANY))
		return false;

	return true;

}

static inline bool match_dhcp_v6_advert(uint32_t payload, uint32_t len) {

	if (len == 0)
		return true;
	if (MATCH(payload, 0x02, ANY, ANY, ANY))
		return false;
	
	return true;

}

static inline bool match_dhcp_v6(lpi_data_t *data) {

	if (!match_dhcp_v6_ports(data->server_port, data->client_port))
		return false;

	if (match_dhcp_v6_solicit(data->payload[0], data->payload_len[0])) {
		if (match_dhcp_v6_advert(data->payload[1], 
				data->payload_len[1])) {
			return true;
		}
	}

	if (match_dhcp_v6_solicit(data->payload[1], data->payload_len[1])) {
		if (match_dhcp_v6_advert(data->payload[0], 
				data->payload_len[0])) {
			return true;
		}
	}

	return false;
}

static inline bool match_dhcp(lpi_data_t *data, lpi_module_t *mod UNUSED) {


	if (match_dhcp_v4(data))
		return true;
	if (match_dhcp_v6(data))
		return true;
	
	return false;
	
}


static lpi_module_t lpi_dhcp = {
	LPI_PROTO_UDP_DHCP,
	LPI_CATEGORY_SERVICES,
	"DHCP",
	8,
	match_dhcp
};

void register_dhcp(LPIModuleMap *mod_map) {
	register_protocol(&lpi_dhcp, mod_map);
}