get method. */ class Reader { private static $DATA_SECTION_SEPARATOR_SIZE = 16; private static $METADATA_START_MARKER = "\xAB\xCD\xEFMaxMind.com"; private static $METADATA_START_MARKER_LENGTH = 14; private static $METADATA_MAX_SIZE = 131072; // 128 * 1024 = 128KB 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 address 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', "\x00" . $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 = 0x0F & $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; $metadataMaxLengthExcludingMarker = min(self::$METADATA_MAX_SIZE, $fileSize) - $markerLength; for ($i = 0; $i <= $metadataMaxLengthExcludingMarker; $i++) { for ($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); } }