class Reader in Smart IP 6.2

Instances of this class provide a reader for the MaxMind DB format. IP addresses can be looked up using the <code>get</code> method.

Hierarchy

• class \MaxMind\Db\Reader

3 files declare their use of Reader

benchmark.php in includes/vendor/maxmind-db/reader/examples/benchmark.php

Reader.php in includes/vendor/geoip2/geoip2/src/Database/Reader.php

ReaderTest.php in includes/vendor/maxmind-db/reader/tests/MaxMind/Db/Test/ReaderTest.php

File

includes/vendor/maxmind-db/reader/src/MaxMind/Db/Reader.php, line 14

Namespace

MaxMind\Db

class Reader {
  private static $DATA_SECTION_SEPARATOR_SIZE = 16;
  private static $METADATA_START_MARKER = "";
  private static $METADATA_START_MARKER_LENGTH = 14;
  private $decoder;
  private $fileHandle;
  private $fileSize;
  private $ipV4Start;
  private $metadata;

  /**
   * Constructs a Reader for the MaxMind DB format. The file passed to it must
   * be a valid MaxMind DB file such as a GeoIp2 database file.
   *
   * @param string $database
   *            the MaxMind DB file to use.
   * @throws \InvalidArgumentException for invalid database path or unknown arguments
   * @throws \MaxMind\Db\Reader\InvalidDatabaseException
   *             if the database is invalid or there is an error reading
   *             from it.
   */
  public function __construct($database) {
    if (func_num_args() != 1) {
      throw new \InvalidArgumentException('The constructor takes exactly one argument.');
    }
    if (!is_readable($database)) {
      throw new \InvalidArgumentException("The file \"{$database}\" does not exist or is not readable.");
    }
    $this->fileHandle = @fopen($database, 'rb');
    if ($this->fileHandle === false) {
      throw new \InvalidArgumentException("Error opening \"{$database}\".");
    }
    $this->fileSize = @filesize($database);
    if ($this->fileSize === false) {
      throw new \UnexpectedValueException("Error determining the size of \"{$database}\".");
    }
    $start = $this
      ->findMetadataStart($database);
    $metadataDecoder = new Decoder($this->fileHandle, $start);
    list($metadataArray) = $metadataDecoder
      ->decode($start);
    $this->metadata = new Metadata($metadataArray);
    $this->decoder = new Decoder($this->fileHandle, $this->metadata->searchTreeSize + self::$DATA_SECTION_SEPARATOR_SIZE);
  }

  /**
   * Looks up the <code>address</code> in the MaxMind DB.
   *
   * @param string $ipAddress
   *            the IP address to look up.
   * @return array the record for the IP address.
   * @throws \BadMethodCallException if this method is called on a closed database.
   * @throws \InvalidArgumentException if something other than a single IP address is passed to the method.
   * @throws InvalidDatabaseException
   *             if the database is invalid or there is an error reading
   *             from it.
   */
  public function get($ipAddress) {
    if (func_num_args() != 1) {
      throw new \InvalidArgumentException('Method takes exactly one argument.');
    }
    if (!is_resource($this->fileHandle)) {
      throw new \BadMethodCallException('Attempt to read from a closed MaxMind DB.');
    }
    if (!filter_var($ipAddress, FILTER_VALIDATE_IP)) {
      throw new \InvalidArgumentException("The value \"{$ipAddress}\" is not a valid IP address.");
    }
    if ($this->metadata->ipVersion == 4 && strrpos($ipAddress, ':')) {
      throw new \InvalidArgumentException("Error looking up {$ipAddress}. You attempted to look up an" . " IPv6 address in an IPv4-only database.");
    }
    $pointer = $this
      ->findAddressInTree($ipAddress);
    if ($pointer == 0) {
      return null;
    }
    return $this
      ->resolveDataPointer($pointer);
  }
  private function findAddressInTree($ipAddress) {

    // XXX - could simplify. Done as a byte array to ease porting
    $rawAddress = array_merge(unpack('C*', inet_pton($ipAddress)));
    $bitCount = count($rawAddress) * 8;

    // The first node of the tree is always node 0, at the beginning of the
    // value
    $node = $this
      ->startNode($bitCount);
    for ($i = 0; $i < $bitCount; $i++) {
      if ($node >= $this->metadata->nodeCount) {
        break;
      }
      $tempBit = 0xff & $rawAddress[$i >> 3];
      $bit = 1 & $tempBit >> 7 - $i % 8;
      $node = $this
        ->readNode($node, $bit);
    }
    if ($node == $this->metadata->nodeCount) {

      // Record is empty
      return 0;
    }
    elseif ($node > $this->metadata->nodeCount) {

      // Record is a data pointer
      return $node;
    }
    throw new InvalidDatabaseException("Something bad happened");
  }
  private function startNode($length) {

    // Check if we are looking up an IPv4 address in an IPv6 tree. If this
    // is the case, we can skip over the first 96 nodes.
    if ($this->metadata->ipVersion == 6 && $length == 32) {
      return $this
        ->ipV4StartNode();
    }

    // The first node of the tree is always node 0, at the beginning of the
    // value
    return 0;
  }
  private function ipV4StartNode() {

    // This is a defensive check. There is no reason to call this when you
    // have an IPv4 tree.
    if ($this->metadata->ipVersion == 4) {
      return 0;
    }
    if ($this->ipV4Start != 0) {
      return $this->ipV4Start;
    }
    $node = 0;
    for ($i = 0; $i < 96 && $node < $this->metadata->nodeCount; $i++) {
      $node = $this
        ->readNode($node, 0);
    }
    $this->ipV4Start = $node;
    return $node;
  }
  private function readNode($nodeNumber, $index) {
    $baseOffset = $nodeNumber * $this->metadata->nodeByteSize;

    // XXX - probably could condense this.
    switch ($this->metadata->recordSize) {
      case 24:
        $bytes = Util::read($this->fileHandle, $baseOffset + $index * 3, 3);
        list(, $node) = unpack('N', "\0" . $bytes);
        return $node;
      case 28:
        $middleByte = Util::read($this->fileHandle, $baseOffset + 3, 1);
        list(, $middle) = unpack('C', $middleByte);
        if ($index == 0) {
          $middle = (0xf0 & $middle) >> 4;
        }
        else {
          $middle = 0xf & $middle;
        }
        $bytes = Util::read($this->fileHandle, $baseOffset + $index * 4, 3);
        list(, $node) = unpack('N', chr($middle) . $bytes);
        return $node;
      case 32:
        $bytes = Util::read($this->fileHandle, $baseOffset + $index * 4, 4);
        list(, $node) = unpack('N', $bytes);
        return $node;
      default:
        throw new InvalidDatabaseException('Unknown record size: ' . $this->metadata->recordSize);
    }
  }
  private function resolveDataPointer($pointer) {
    $resolved = $pointer - $this->metadata->nodeCount + $this->metadata->searchTreeSize;
    if ($resolved > $this->fileSize) {
      throw new InvalidDatabaseException("The MaxMind DB file's search tree is corrupt");
    }
    list($data) = $this->decoder
      ->decode($resolved);
    return $data;
  }

  /*
   * This is an extremely naive but reasonably readable implementation. There
   * are much faster algorithms (e.g., Boyer-Moore) for this if speed is ever
   * an issue, but I suspect it won't be.
   */
  private function findMetadataStart($filename) {
    $handle = $this->fileHandle;
    $fstat = fstat($handle);
    $fileSize = $fstat['size'];
    $marker = self::$METADATA_START_MARKER;
    $markerLength = self::$METADATA_START_MARKER_LENGTH;
    for ($i = 0; $i < $fileSize - $markerLength + 1; $i++) {
      for ($j = 0; $j < $markerLength; $j++) {
        fseek($handle, $fileSize - $i - $j - 1);
        $matchBit = fgetc($handle);
        if ($matchBit != $marker[$markerLength - $j - 1]) {
          continue 2;
        }
      }
      return $fileSize - $i;
    }
    throw new InvalidDatabaseException("Error opening database file ({$filename}). " . 'Is this a valid MaxMind DB file?');
  }

  /**
   * @throws \InvalidArgumentException if arguments are passed to the method.
   * @throws \BadMethodCallException if the database has been closed.
   * @return Metadata object for the database.
   */
  public function metadata() {
    if (func_num_args()) {
      throw new \InvalidArgumentException('Method takes no arguments.');
    }

    // Not technically required, but this makes it consistent with
    // C extension and it allows us to change our implementation later.
    if (!is_resource($this->fileHandle)) {
      throw new \BadMethodCallException('Attempt to read from a closed MaxMind DB.');
    }
    return $this->metadata;
  }

  /**
   * Closes the MaxMind DB and returns resources to the system.
   *
   * @throws \Exception
   *             if an I/O error occurs.
   */
  public function close() {
    if (!is_resource($this->fileHandle)) {
      throw new \BadMethodCallException('Attempt to close a closed MaxMind DB.');
    }
    fclose($this->fileHandle);
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Reader::$DATA_SECTION_SEPARATOR_SIZE	private static	property
Reader::$decoder	private	property
Reader::$fileHandle	private	property
Reader::$fileSize	private	property
Reader::$ipV4Start	private	property
Reader::$metadata	private	property
Reader::$METADATA_START_MARKER	private static	property
Reader::$METADATA_START_MARKER_LENGTH	private static	property
Reader::close	public	function	Closes the MaxMind DB and returns resources to the system.
Reader::findAddressInTree	private	function
Reader::findMetadataStart	private	function
Reader::get	public	function	Looks up the <code>address</code> in the MaxMind DB.
Reader::ipV4StartNode	private	function
Reader::metadata	public	function
Reader::readNode	private	function
Reader::resolveDataPointer	private	function
Reader::startNode	private	function
Reader::__construct	public	function	Constructs a Reader for the MaxMind DB format. The file passed to it must be a valid MaxMind DB file such as a GeoIp2 database file.