librenms-librenms/includes/discovery/arp-table.inc.php

<?php
  unset ($mac_table);

  echo("ARP Table : ");

  $ipNetToMedia_data = snmp_walk($device, 'ipNetToMediaPhysAddress', '-Oq', 'IP-MIB');
  $ipNetToMedia_data = str_replace("ipNetToMediaPhysAddress.", "", trim($ipNetToMedia_data));
  $ipNetToMedia_data = str_replace("IP-MIB::", "", trim($ipNetToMedia_data));
  #echo("$ipNetToMedia_data\n");
  #echo("done\n");
  foreach(explode("\n", $ipNetToMedia_data) as $data) {
    list($oid, $mac) = explode(" ", $data);
    list($if, $first, $second, $third, $fourth) = explode(".", $oid);
    list($m_a, $m_b, $m_c, $m_d, $m_e, $m_f) = explode(":", $mac); 
    $interface = mysql_fetch_array(mysql_query("SELECT * FROM ports WHERE device_id = '".$device['device_id']."' AND ifIndex = '".$if."'"));
    $ip = $first .".". $second .".". $third .".". $fourth;
    $m_a = zeropad($m_a);
    $m_b = zeropad($m_b);
    $m_c = zeropad($m_c);
    $m_d = zeropad($m_d);
    $m_e = zeropad($m_e);
    $m_f = zeropad($m_f);
    $md_a = hexdec($m_a);
    $md_b = hexdec($m_b);
    $md_c = hexdec($m_c);
    $md_d = hexdec($m_d);
    $md_e = hexdec($m_e);
    $md_f = hexdec($m_f);
    $mac = "$m_a:$m_b:$m_c:$m_d:$m_e:$m_f"; 
    $mac_table[$if][$mac]['ip'] =  $ip;
    $mac_table[$if][$mac]['ciscomac'] = "$m_a$m_b.$m_c$m_d.$m_e$m_f";
    $clean_mac = $m_a . $m_b . $m_c . $m_d . $m_e . $m_f;    
    $mac_table[$if][$mac]['cleanmac'] = $clean_mac;
    $interface_id = $interface['interface_id'];
    $mac_table[$interface_id][$clean_mac] = 1;
    if(mysql_result(mysql_query("SELECT COUNT(*) from ipv4_mac WHERE interface_id = '".$interface['interface_id']."' AND ipv4_address = '$ip'"),0)) {
      $sql = "UPDATE `ipv4_mac` SET `mac_address` = '$clean_mac' WHERE interface_id = '".$interface['interface_id']."' AND ipv4_address = '$ip'";
      $old_mac = mysql_fetch_row(mysql_query("SELECT mac_address from ipv4_mac WHERE ipv4_address='$ip' AND interface_id = '".$interface['interface_id']."'"));
      if($clean_mac != $old_mac[0]) 
      {
        if ($debug) { echo "Changed mac address for $ip from $old_mac[0] to $clean_mac\n"; }
        log_event("MAC change: $ip : " . mac_clean_to_readable($old_mac[0]) . " -> " . mac_clean_to_readable($clean_mac), $device, "interface", $interface['interface_id']);
      }
      mysql_query($sql);
      echo(".");
    } else {
      echo("+");
      #echo("Add MAC $mac\n");
      mysql_query("INSERT INTO `ipv4_mac` (interface_id, mac_address, ipv4_address) VALUES ('".$interface['interface_id']."','$clean_mac','$ip')");
    }
    $interface_id = $interface['interface_id'];
  }
  $sql = "SELECT * from ipv4_mac AS M, ports as I WHERE M.interface_id = I.interface_id and I.device_id = '".$device['device_id']."'";
  $query = mysql_query($sql);
  while($entry = mysql_fetch_array($query)) {
    $entry_mac = $entry['mac_address'];
    $entry_if  = $entry['interface_id'];
    if(!$mac_table[$entry_if][$entry_mac]) {
      mysql_query("DELETE FROM ipv4_mac WHERE interface_id = '".$entry_if."' AND mac_address = '".$entry_mac."'");
      #echo("Removing MAC $entry_mac from interface ".$interface['ifName']);
      echo("-");
    } 
  }

  echo("\n");
  unset($mac);

?>