/*

 * iax.c

 *

 * Copyright (C) 2009-11 - ipoque GmbH

 * Copyright (C) 2011-26 - 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_IAX

#include "ndpi_api.h"

#include "ndpi_private.h"

#define NDPI_IAX_MAX_INFORMATION_ELEMENTS 15

static void ndpi_int_iax_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)

{

  ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_IAX, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);

}

static void ndpi_search_setup_iax(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct *packet = &ndpi_struct->packet;

  u_int8_t i;

  u_int16_t packet_len;

  if (            /* 1. iax is udp based, port 4569 */

      (packet->udp->source == htons(4569) || packet->udp->dest == htons(4569))

      /* check for iax new packet */

      && packet->payload_packet_len >= 12

      /* check for dst call id == 0, do not check for highest bit (packet retransmission) */

      // && (ntohs(get_u_int16_t(packet->payload, 2)) & 0x7FFF) == 0

      /* check full IAX packet  */

      && (packet->payload[0] & 0x80) != 0

      /* outbound seq == 0 */

      && packet->payload[8] == 0

      /* inbound seq == 0 || 1  */

      && (packet->payload[9] == 0 || packet->payload[9] == 0x01)

      /*  */

      && packet->payload[10] == 0x06

      /* IAX type: 0-15 */

      && packet->payload[11] <= 15) {

    if (packet->payload_packet_len == 12) {

      NDPI_LOG_INFO(ndpi_struct, "found IAX\n");

      ndpi_int_iax_add_connection(ndpi_struct, flow);

      return;

    }

    packet_len = 12;

    for(i = 0; i < NDPI_IAX_MAX_INFORMATION_ELEMENTS; i++) {

      if ((packet_len+1) >= packet->payload_packet_len)

  break;      

      packet_len = packet_len + 2 + packet->payload[packet_len + 1];

      if(packet_len == packet->payload_packet_len) {

  NDPI_LOG_INFO(ndpi_struct, "found IAX\n");

  ndpi_int_iax_add_connection(ndpi_struct, flow);

  return;

      }

    }

  }

  NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

}

static void ndpi_search_iax(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct *packet = &ndpi_struct->packet;

  if(packet->udp 

     && (flow->detected_protocol_stack[0] == NDPI_PROTOCOL_UNKNOWN))

    ndpi_search_setup_iax(ndpi_struct, flow);

}

void init_iax_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  ndpi_register_dissector("IAX", ndpi_struct,

                     ndpi_search_iax,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,

                     1, NDPI_PROTOCOL_IAX);

}