/*
 *
 * 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"

/* Thanks to Remy Mudingay for providing traces to identify this protocol */

static inline bool match_viber_request(uint32_t payload, uint32_t plen) {
	if (plen != 12 && plen != 16)
		return false;
	if (MATCH(payload, ANY, ANY, 0x03, 0x00))
		return true;
	return false;

}

static inline bool match_viber_response(uint32_t payload, uint32_t plen) {
	if (plen == 0)
		return true;
	if (plen != 12)
		return false;
	if (MATCH(payload, ANY, ANY, 0x04, 0x00))
		return true;
	return false;

}

static inline bool match_viber_aws0c(uint32_t payload, uint32_t plen) {

	if (MATCH(payload, ANY, ANY, 0x0c, 0x00))
		return true;
	return false;

}

static inline bool match_viber_aws01(uint32_t payload, uint32_t plen) {

	if (MATCH(payload, ANY, ANY, 0x01, 0x00))
		return true;
	return false;

}

static inline bool same_viber_id(uint32_t pl_a, uint32_t pl_b) {

	if ((pl_a & 0xffff) == (pl_b & 0xffff))
		return true;
	return false;

}

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

	/* These rules target the little 12 byte exchanges that go on */
	if (match_viber_request(data->payload[0], data->payload_len[0])) {
		if (match_viber_response(data->payload[1], data->payload_len[1]))
			return true;
		if (match_viber_request(data->payload[1], data->payload_len[1]))
			return true;
	}

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

	/* This targets the viber flow that goes to the AWS server */
	if (match_viber_aws0c(data->payload[0], data->payload_len[0])) {
		if (match_viber_aws01(data->payload[1], data->payload_len[1])) 
		{
			if (same_viber_id(data->payload[0], data->payload[1]))
				return true;
		}
	}

	if (match_viber_aws0c(data->payload[1], data->payload_len[1])) {
		if (match_viber_aws01(data->payload[0], data->payload_len[0])) 
		{
			if (same_viber_id(data->payload[0], data->payload[1]))
				return true;
		}
	}

	return false;
}

static lpi_module_t lpi_viber_udp = {
	LPI_PROTO_UDP_VIBER,
	LPI_CATEGORY_VOIP,
	"Viber_UDP",
	18,
	match_viber_udp
};

void register_viber_udp(LPIModuleMap *mod_map) {
	register_protocol(&lpi_viber_udp, mod_map);
}

