/*
 *
 * (C) 2013-25 - ntop.org
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include "ntop_includes.h"

/* ************************************ */

FlowHash::FlowHash(NetworkInterface *_iface, u_int _num_hashes,
                   u_int _max_hash_size)
    : GenericHash(_iface, _num_hashes, _max_hash_size, "FlowHash") {
  if(trace_new_delete) ntop->getTrace()->traceEvent(TRACE_NORMAL, "[new] %s", __FILE__);
};

/* ************************************ */

static u_int16_t max_num_loops = 0;

Flow* FlowHash::find(Mac *src_mac, Mac *dst_mac, IpAddress *src_ip,
                     IpAddress *dst_ip, u_int16_t src_port, u_int16_t dst_port,
                     u_int16_t vlanId, u_int16_t observation_point_id,
                     u_int32_t private_flow_id, u_int8_t protocol,
                     const ICMPinfo *const icmp_info, bool *src2dst_direction,
                     bool is_inline_call, Flow **unswapped_flow) {
  u_int32_t hash;
  Flow *head;
  u_int16_t num_loops = 0;

  hash = src_ip->key() + dst_ip->key() +
    (icmp_info ? icmp_info->key() : 0) +
    private_flow_id +
    src_port + dst_port + vlanId +  protocol;

#ifdef USE_MAC_IN_KEY_WITH_DHCP
  if((src_ip->key() == 0) && (dst_ip->key() == 0xFFFFFFFF)) {
    /* Add the MAC address of the source host (dst_mac is not necessary as it's FF:FF:FF:FF:FF:FF) */
    if(src_mac != NULL) hash += src_mac->key();
  }
#endif

  hash %= num_hashes;

  head = (Flow *)table[hash];

  *unswapped_flow = NULL;

#if 0
  ntop->getTrace()->traceEvent(TRACE_NORMAL, "[%s] %u:%u / %u:%u [icmp key: %u]"
			       "[priv flow id: %u][vlan: %u][protocol: %u]"
			       "[hash: %u][head: 0x%x]",
			       iface->get_name(),
			       src_ip->key(), ntohs(src_port), dst_ip->key(), ntohs(dst_port),
			       icmp_info ? icmp_info->key() : 0,
			       private_flow_id, vlanId, protocol, hash, head);
#endif

  if (!head) return (NULL);

  if (!is_inline_call) locks[hash]->rdlock(__FILE__, __LINE__);

  while (head) {
    if (!head->idle() &&
        head->equal(src_mac, dst_mac, src_ip, dst_ip, src_port, dst_port,
                    vlanId, observation_point_id, private_flow_id, protocol,
                    icmp_info, src2dst_direction)) {
      if (num_loops > max_num_loops) {
        ntop->getTrace()->traceEvent(TRACE_INFO, "DEBUG: [Num loops: %u][hashId: %u]", num_loops, hash);
        max_num_loops = num_loops;
      }

      if (head->is_swap_requested()) {
        /*
          This is a good flow but in the wrong direction
          hence we remember the flow unswapped but merge
          data with the flow with the correct direction
         */
        *unswapped_flow = head;
        head = NULL;
      }

      break;
    } else
      head = (Flow *)head->next(), num_loops++;
  }

  if (num_loops > max_num_loops) {
    ntop->getTrace()->traceEvent(TRACE_INFO, "DEBUG: [Num loops: %u][hashId: %u]", num_loops, hash);
    max_num_loops = num_loops;
  }

  if (!is_inline_call) locks[hash]->unlock(__FILE__, __LINE__);

  return (head);
}

/* ************************************ */

Flow *FlowHash::findByKeyAndHashId(u_int32_t key, u_int32_t hash_id) {
  u_int32_t hash = key % num_hashes;
  Flow *head = (Flow *)table[hash];

  if (head == NULL) return (NULL);

  locks[hash]->rdlock(__FILE__, __LINE__);

  while (head) {
    if ((!head->idle()) && (head->get_hash_entry_id() == hash_id))
      break;
    else
      head = (Flow *)head->next();
  }

  locks[hash]->unlock(__FILE__, __LINE__);

  return ((Flow *)head);
}
