/*
 * pptp.c
 *
 * Copyright (C) 2009-2011 by ipoque GmbH
 * Copyright (C) 2011-18 - ntop.org
 *
 * This file is part of nDPI, an open source deep packet inspection
 * library based on the OpenDPI and PACE technology by ipoque GmbH
 *
 * nDPI 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.
 *
 * nDPI 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 nDPI.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "ndpi_protocol_ids.h"

#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_PPTP

#include "ndpi_api.h"

static void ndpi_int_pptp_add_connection(struct ndpi_detection_module_struct
        *ndpi_struct, struct ndpi_flow_struct *flow)
{
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_PPTP);
}

void ndpi_search_pptp(struct ndpi_detection_module_struct
        *ndpi_struct, struct ndpi_flow_struct *flow)
{
    struct ndpi_packet_struct *packet = &flow->packet;

    NDPI_LOG_DBG(ndpi_struct, "search pptp\n");

    if (packet->payload_packet_len >= 10 && get_u_int16_t(packet->payload, 0) == htons(packet->payload_packet_len)
            && get_u_int16_t(packet->payload, 2) == htons(0x0001)	/* message type: control message */
            &&get_u_int32_t(packet->payload, 4) == htonl(0x1a2b3c4d)	/* cookie: correct */
            &&(get_u_int16_t(packet->payload, 8) == htons(0x0001)	/* control type: start-control-connection-request */
              )) {

        NDPI_LOG_INFO(ndpi_struct, "found pptp\n");
        ndpi_int_pptp_add_connection(ndpi_struct, flow);
        return;
    }

    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}


void init_pptp_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("PPTP", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_PPTP,
            ndpi_search_pptp,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}
