/*
 * sip.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_SIP

#include "ndpi_api.h"

static void ndpi_int_sip_add_connection(struct ndpi_detection_module_struct *ndpi_struct,
        struct ndpi_flow_struct *flow, u_int8_t due_to_correlation) {
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_SIP);
}

#if !defined(WIN32)
static inline
#elif defined(MINGW_GCC)
__mingw_forceinline static
#else
__forceinline static
#endif
void ndpi_search_sip_handshake(struct ndpi_detection_module_struct
        *ndpi_struct, struct ndpi_flow_struct *flow)
{
    struct ndpi_packet_struct *packet = &flow->packet;
    const u_int8_t *packet_payload = packet->payload;
    u_int32_t payload_len = packet->payload_packet_len;

    if (payload_len > 4) {
        /* search for STUN Turn ChannelData Prefix */
        u_int16_t message_len = ntohs(get_u_int16_t(packet->payload, 2));
        if (payload_len - 4 == message_len) {
            NDPI_LOG_DBG2(ndpi_struct, "found STUN TURN ChannelData prefix\n");
            payload_len -= 4;
            packet_payload += 4;
        }
    }

    if (payload_len >= 14)
    {

        if ((memcmp(packet_payload, "NOTIFY ", 7) == 0 || memcmp(packet_payload, "notify ", 7) == 0)
                && (memcmp(&packet_payload[7], "SIP:", 4) == 0 || memcmp(&packet_payload[7], "sip:", 4) == 0)) {

            NDPI_LOG_INFO(ndpi_struct, "found sip NOTIFY\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }

        if ((memcmp(packet_payload, "REGISTER ", 9) == 0 || memcmp(packet_payload, "register ", 9) == 0)
                && (memcmp(&packet_payload[9], "SIP:", 4) == 0 || memcmp(&packet_payload[9], "sip:", 4) == 0)) {

            NDPI_LOG_INFO(ndpi_struct, "found sip REGISTER\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }

        if ((memcmp(packet_payload, "INVITE ", 7) == 0 || memcmp(packet_payload, "invite ", 7) == 0)
                && (memcmp(&packet_payload[7], "SIP:", 4) == 0 || memcmp(&packet_payload[7], "sip:", 4) == 0)) {
            NDPI_LOG_INFO(ndpi_struct, "found sip INVITE\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }

        /* seen this in second direction on the third position,
         * maybe it could be deleted, if somebody sees it in the first direction,
         * please delete this comment.
         */

        /*
           if (memcmp(packet_payload, "SIP/2.0 200 OK", 14) == 0 || memcmp(packet_payload, "sip/2.0 200 OK", 14) == 0) {
           NDPI_LOG_INFO(ndpi_struct, "found sip SIP/2.0 0K\n");
           ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
           return;
           }
           */
        if (memcmp(packet_payload, "SIP/2.0 ", 8) == 0 || memcmp(packet_payload, "sip/2.0 ", 8) == 0) {
            NDPI_LOG_INFO(ndpi_struct, "found sip SIP/2.0 *\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }

        if ((memcmp(packet_payload, "BYE ", 4) == 0 || memcmp(packet_payload, "bye ", 4) == 0)
                && (memcmp(&packet_payload[4], "SIP:", 4) == 0 || memcmp(&packet_payload[4], "sip:", 4) == 0)) {
            NDPI_LOG_INFO(ndpi_struct, "found sip BYE\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }

        if ((memcmp(packet_payload, "ACK ", 4) == 0 || memcmp(packet_payload, "ack ", 4) == 0)
                && (memcmp(&packet_payload[4], "SIP:", 4) == 0 || memcmp(&packet_payload[4], "sip:", 4) == 0)) {
            NDPI_LOG_INFO(ndpi_struct, "found sip ACK\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }

        if ((memcmp(packet_payload, "CANCEL ", 7) == 0 || memcmp(packet_payload, "cancel ", 7) == 0)
                && (memcmp(&packet_payload[7], "SIP:", 4) == 0 || memcmp(&packet_payload[7], "sip:", 4) == 0)) {
            NDPI_LOG_INFO(ndpi_struct, "found sip CANCEL\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }

        if ((memcmp(packet_payload, "PUBLISH ", 8) == 0 || memcmp(packet_payload, "publish ", 8) == 0)
	    && (memcmp(&packet_payload[8], "SIP:", 4) == 0 || memcmp(&packet_payload[8], "sip:", 4) == 0)) {
	  NDPI_LOG_INFO(ndpi_struct, "found sip PUBLISH\n");
	  ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
	  return;
	}

        if ((memcmp(packet_payload, "SUBSCRIBE ", 10) == 0 || memcmp(packet_payload, "subscribe ", 10) == 0)
	    && (memcmp(&packet_payload[10], "SIP:", 4) == 0 || memcmp(&packet_payload[10], "sip:", 4) == 0)) {
	  NDPI_LOG_INFO(ndpi_struct, "found sip SUBSCRIBE\n");
	  ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
	  return;
	}
        
        /* SIP message extension RFC 3248 */
        if ((memcmp(packet_payload, "MESSAGE ", 8) == 0 || memcmp(packet_payload, "message ", 8) == 0)
	    && (memcmp(&packet_payload[8], "SIP:", 4) == 0 || memcmp(&packet_payload[8], "sip:", 4) == 0)) {
	  NDPI_LOG_INFO(ndpi_struct, "found sip MESSAGE\n");
	  ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
	  return;
	}

        /* Courtesy of Miguel Quesada <mquesadab@gmail.com> */
        if ((memcmp(packet_payload, "OPTIONS ", 8) == 0
                    || memcmp(packet_payload, "options ", 8) == 0)
                && (memcmp(&packet_payload[8], "SIP:", 4) == 0
                    || memcmp(&packet_payload[8], "sip:", 4) == 0)) {
            NDPI_LOG_INFO(ndpi_struct, "found sip OPTIONS\n");
            ndpi_int_sip_add_connection(ndpi_struct, flow, 0);
            return;
        }
    }

    /* add bitmask for tcp only, some stupid udp programs
     * send a very few (< 10 ) packets before invite (mostly a 0x0a0x0d, but just search the first 3 payload_packets here */
    if (packet->udp != NULL && flow->packet_counter < 20) {
        NDPI_LOG_DBG2(ndpi_struct, "need next packet\n");
        return;
    }

    /* for STUN flows we need some more packets */
    if (packet->udp != NULL && flow->detected_protocol == NDPI_PROTOCOL_STUN && flow->packet_counter < 40) {
        NDPI_LOG_DBG2(ndpi_struct, "need next STUN packet\n");
        return;
    }

    if (payload_len == 4 && get_u_int32_t(packet_payload, 0) == 0) {
        NDPI_LOG_DBG2(ndpi_struct, "maybe sip. need next packet\n");
        return;
    }

    if (payload_len > 30 && packet_payload[0] == 0x90
            && packet_payload[3] == payload_len - 20 && get_u_int32_t(packet_payload, 4) == 0
            && get_u_int32_t(packet_payload, 8) == 0) {
        flow->sip_yahoo_voice = 1;
        NDPI_LOG_DBG2(ndpi_struct, "maybe sip yahoo. need next packet\n");
    }
    if (flow->sip_yahoo_voice && flow->packet_counter < 10) {
        return;
    }

    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}

void ndpi_search_sip(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 sip\n");

    /* skip marked packets */
    if (packet->detected_protocol != NDPI_PROTOCOL_SIP) {
        if (packet->tcp_retransmission == 0) {
            ndpi_search_sip_handshake(ndpi_struct, flow);
        }
    }
}


void init_sip_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("SIP", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_SIP,
            ndpi_search_sip,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD,/* Fix courtesy of Miguel Quesada <mquesadab@gmail.com> */
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}

