/*
 * eaq.c
 *
 * Copyright (C) 2015 - ntop.org
 *
 * This module 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.
 *
 * This module 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.
 * If not, see <http://www.gnu.org/licenses/>.
 *
 */


#include "ndpi_api.h"

#define EAQ_DEFAULT_PORT   6000
#define EAQ_DEFAULT_SIZE     16

#ifdef NDPI_PROTOCOL_EAQ
static void ndpi_int_eaq_add_connection(struct ndpi_detection_module_struct *ndpi_struct,
					struct ndpi_flow_struct *flow) {
  ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_EAQ, NDPI_REAL_PROTOCOL);
}


void ndpi_search_eaq(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {
  struct ndpi_packet_struct *packet = &flow->packet;
  u_int16_t sport = ntohs(packet->udp->source), dport = ntohs(packet->udp->dest);
  unsigned char *vers;
  int ver_offs;
  
  if((packet->payload_packet_len != EAQ_DEFAULT_SIZE)
     || ((sport != EAQ_DEFAULT_PORT) && (dport != EAQ_DEFAULT_PORT))) {
  exclude_eaq:
    NDPI_LOG(NDPI_PROTOCOL_EAQ, ndpi_struct, NDPI_LOG_DEBUG, "Exclude eaq.\n");
    NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_EAQ);
    return;
  }

  if(packet->udp != NULL) {
    u_int32_t seq = (packet->payload[0] * 1000) + (packet->payload[1] * 100) + (packet->payload[2] * 10) + packet->payload[3];
    
    if(flow->l4.udp.eaq_pkt_id == 0)
      flow->l4.udp.eaq_sequence = seq;
    else {
      if((flow->l4.udp.eaq_sequence == seq) || ((flow->l4.udp.eaq_sequence+1) == seq)) {
	; /* Looks good */
      } else
	goto exclude_eaq;
    }

    if(++flow->l4.udp.eaq_pkt_id == 4) {
      /* We have collected enough packets so we assume it's EAQ */
      NDPI_LOG(NDPI_PROTOCOL_EAQ, ndpi_struct, NDPI_LOG_DEBUG, "found eaq.\n");
      ndpi_int_eaq_add_connection(ndpi_struct, flow);
    }
  } else
    goto exclude_eaq;
}
#endif