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<?php |
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|
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declare( strict_types=1 ); |
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|
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namespace MaxMind\Db; |
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|
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use MaxMind\Db\Reader\Decoder; |
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use MaxMind\Db\Reader\InvalidDatabaseException; |
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use MaxMind\Db\Reader\Metadata; |
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use MaxMind\Db\Reader\Util; |
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|
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/** |
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* Instances of this class provide a reader for the MaxMind DB format. IP |
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* addresses can be looked up using the get method. |
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*/ |
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class Reader { |
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/** |
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* @var int |
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*/ |
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private static $DATA_SECTION_SEPARATOR_SIZE = 16; |
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|
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/** |
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* @var string |
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*/ |
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private static $METADATA_START_MARKER = "\xAB\xCD\xEFMaxMind.com"; |
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|
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/** |
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* @var int |
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*/ |
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private static $METADATA_START_MARKER_LENGTH = 14; |
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|
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/** |
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* @var int |
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*/ |
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private static $METADATA_MAX_SIZE = 131072; // 128 * 1024 = 128KiB |
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|
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/** |
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* @var Decoder |
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*/ |
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private $decoder; |
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|
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/** |
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* @var resource |
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*/ |
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private $fileHandle; |
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|
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/** |
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* @var int |
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*/ |
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private $fileSize; |
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|
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/** |
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* @var int |
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*/ |
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private $ipV4Start; |
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|
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/** |
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* @var Metadata |
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*/ |
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private $metadata; |
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|
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/** |
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* Constructs a Reader for the MaxMind DB format. The file passed to it must |
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* be a valid MaxMind DB file such as a GeoIp2 database file. |
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* |
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* @param string $database |
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* the MaxMind DB file to use |
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* |
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* @throws \InvalidArgumentException for invalid database path or unknown arguments |
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* @throws InvalidDatabaseException |
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* if the database is invalid or there is an error reading |
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* from it |
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*/ |
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public function __construct( string $database ) { |
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if ( \func_num_args() !== 1 ) { |
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throw new \ArgumentCountError( |
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sprintf( '%s() expects exactly 1 parameter, %d given', __METHOD__, \func_num_args() ) |
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); |
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} |
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|
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$fileHandle = @fopen( $database, 'rb' ); |
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if ( $fileHandle === false ) { |
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throw new \InvalidArgumentException( |
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"The file \"$database\" does not exist or is not readable." |
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); |
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} |
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$this->fileHandle = $fileHandle; |
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|
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$fileSize = @filesize( $database ); |
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if ( $fileSize === false ) { |
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throw new \UnexpectedValueException( |
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"Error determining the size of \"$database\"." |
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); |
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} |
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$this->fileSize = $fileSize; |
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|
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$start = $this->findMetadataStart( $database ); |
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$metadataDecoder = new Decoder( $this->fileHandle, $start ); |
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[ $metadataArray ] = $metadataDecoder->decode( $start ); |
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$this->metadata = new Metadata( $metadataArray ); |
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$this->decoder = new Decoder( |
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$this->fileHandle, |
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$this->metadata->searchTreeSize + self::$DATA_SECTION_SEPARATOR_SIZE |
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); |
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$this->ipV4Start = $this->ipV4StartNode(); |
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} |
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|
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/** |
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* Retrieves the record for the IP address. |
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* |
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* @param string $ipAddress |
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* the IP address to look up |
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* |
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* @return mixed the record for the IP address |
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* @throws \InvalidArgumentException if something other than a single IP address is passed to the method |
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* @throws InvalidDatabaseException |
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* if the database is invalid or there is an error reading |
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* from it |
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* |
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* @throws \BadMethodCallException if this method is called on a closed database |
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*/ |
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public function get( string $ipAddress ) { |
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if ( \func_num_args() !== 1 ) { |
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throw new \ArgumentCountError( |
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sprintf( '%s() expects exactly 1 parameter, %d given', __METHOD__, \func_num_args() ) |
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); |
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} |
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[ $record ] = $this->getWithPrefixLen( $ipAddress ); |
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|
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return $record; |
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} |
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|
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/** |
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* Retrieves the record for the IP address and its associated network prefix length. |
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* |
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* @param string $ipAddress |
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* the IP address to look up |
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* |
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* @return array an array where the first element is the record and the |
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* second the network prefix length for the record |
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* @throws \InvalidArgumentException if something other than a single IP address is passed to the method |
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* @throws InvalidDatabaseException |
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* if the database is invalid or there is an error reading |
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* from it |
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* |
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* @throws \BadMethodCallException if this method is called on a closed database |
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*/ |
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public function getWithPrefixLen( string $ipAddress ): array { |
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if ( \func_num_args() !== 1 ) { |
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throw new \ArgumentCountError( |
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sprintf( '%s() expects exactly 1 parameter, %d given', __METHOD__, \func_num_args() ) |
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); |
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} |
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|
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if ( ! \is_resource( $this->fileHandle ) ) { |
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throw new \BadMethodCallException( |
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'Attempt to read from a closed MaxMind DB.' |
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); |
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} |
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|
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[ $pointer, $prefixLen ] = $this->findAddressInTree( $ipAddress ); |
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if ( $pointer === 0 ) { |
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return [ null, $prefixLen ]; |
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} |
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|
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return [ $this->resolveDataPointer( $pointer ), $prefixLen ]; |
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} |
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|
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private function findAddressInTree( string $ipAddress ): array { |
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$packedAddr = @inet_pton( $ipAddress ); |
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if ( $packedAddr === false ) { |
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throw new \InvalidArgumentException( |
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"The value \"$ipAddress\" is not a valid IP address." |
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); |
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} |
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|
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$rawAddress = unpack( 'C*', $packedAddr ); |
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|
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$bitCount = \count( $rawAddress ) * 8; |
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|
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// The first node of the tree is always node 0, at the beginning of the |
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// value |
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$node = 0; |
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|
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$metadata = $this->metadata; |
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|
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// Check if we are looking up an IPv4 address in an IPv6 tree. If this |
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// is the case, we can skip over the first 96 nodes. |
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if ( $metadata->ipVersion === 6 ) { |
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if ( $bitCount === 32 ) { |
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$node = $this->ipV4Start; |
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} |
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} elseif ( $metadata->ipVersion === 4 && $bitCount === 128 ) { |
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throw new \InvalidArgumentException( |
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"Error looking up $ipAddress. You attempted to look up an" |
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. ' IPv6 address in an IPv4-only database.' |
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); |
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} |
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|
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$nodeCount = $metadata->nodeCount; |
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|
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for ( $i = 0; $i < $bitCount && $node < $nodeCount; ++ $i ) { |
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$tempBit = 0xFF & $rawAddress[ ( $i >> 3 ) + 1 ]; |
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$bit = 1 & ( $tempBit >> 7 - ( $i % 8 ) ); |
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|
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$node = $this->readNode( $node, $bit ); |
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} |
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if ( $node === $nodeCount ) { |
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// Record is empty |
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return [ 0, $i ]; |
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} |
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if ( $node > $nodeCount ) { |
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// Record is a data pointer |
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return [ $node, $i ]; |
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} |
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|
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throw new InvalidDatabaseException( |
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'Invalid or corrupt database. Maximum search depth reached without finding a leaf node' |
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); |
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} |
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|
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private function ipV4StartNode(): int { |
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// If we have an IPv4 database, the start node is the first node |
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if ( $this->metadata->ipVersion === 4 ) { |
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return 0; |
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} |
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|
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$node = 0; |
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|
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for ( $i = 0; $i < 96 && $node < $this->metadata->nodeCount; ++ $i ) { |
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$node = $this->readNode( $node, 0 ); |
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} |
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|
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return $node; |
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} |
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|
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private function readNode( int $nodeNumber, int $index ): int { |
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$baseOffset = $nodeNumber * $this->metadata->nodeByteSize; |
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|
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switch ( $this->metadata->recordSize ) { |
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case 24: |
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$bytes = Util::read( $this->fileHandle, $baseOffset + $index * 3, 3 ); |
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[ , $node ] = unpack( 'N', "\x00" . $bytes ); |
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|
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return $node; |
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|
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case 28: |
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$bytes = Util::read( $this->fileHandle, $baseOffset + 3 * $index, 4 ); |
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if ( $index === 0 ) { |
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$middle = ( 0xF0 & \ord( $bytes[3] ) ) >> 4; |
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} else { |
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$middle = 0x0F & \ord( $bytes[0] ); |
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} |
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[ , $node ] = unpack( 'N', \chr( $middle ) . substr( $bytes, $index, 3 ) ); |
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|
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return $node; |
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|
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case 32: |
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$bytes = Util::read( $this->fileHandle, $baseOffset + $index * 4, 4 ); |
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[ , $node ] = unpack( 'N', $bytes ); |
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|
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return $node; |
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|
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default: |
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throw new InvalidDatabaseException( |
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'Unknown record size: ' |
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. $this->metadata->recordSize |
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); |
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} |
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} |
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|
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/** |
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* @return mixed |
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*/ |
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private function resolveDataPointer( int $pointer ) { |
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$resolved = $pointer - $this->metadata->nodeCount |
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+ $this->metadata->searchTreeSize; |
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if ( $resolved >= $this->fileSize ) { |
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throw new InvalidDatabaseException( |
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"The MaxMind DB file's search tree is corrupt" |
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); |
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} |
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|
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[ $data ] = $this->decoder->decode( $resolved ); |
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|
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return $data; |
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} |
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|
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/* |
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* This is an extremely naive but reasonably readable implementation. There |
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* are much faster algorithms (e.g., Boyer-Moore) for this if speed is ever |
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* an issue, but I suspect it won't be. |
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*/ |
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private function findMetadataStart( string $filename ): int { |
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$handle = $this->fileHandle; |
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$fstat = fstat( $handle ); |
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$fileSize = $fstat['size']; |
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$marker = self::$METADATA_START_MARKER; |
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$markerLength = self::$METADATA_START_MARKER_LENGTH; |
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|
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$minStart = $fileSize - min( self::$METADATA_MAX_SIZE, $fileSize ); |
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|
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for ( $offset = $fileSize - $markerLength; $offset >= $minStart; -- $offset ) { |
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if ( fseek( $handle, $offset ) !== 0 ) { |
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break; |
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} |
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|
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$value = fread( $handle, $markerLength ); |
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if ( $value === $marker ) { |
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return $offset + $markerLength; |
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} |
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} |
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|
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throw new InvalidDatabaseException( |
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"Error opening database file ($filename). " . |
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'Is this a valid MaxMind DB file?' |
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); |
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} |
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|
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/** |
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* @return Metadata object for the database |
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* @throws \BadMethodCallException if the database has been closed |
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* |
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* @throws \InvalidArgumentException if arguments are passed to the method |
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*/ |
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public function metadata(): Metadata { |
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if ( \func_num_args() ) { |
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throw new \ArgumentCountError( |
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sprintf( '%s() expects exactly 0 parameters, %d given', __METHOD__, \func_num_args() ) |
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); |
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} |
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|
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// Not technically required, but this makes it consistent with |
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// C extension and it allows us to change our implementation later. |
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if ( ! \is_resource( $this->fileHandle ) ) { |
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throw new \BadMethodCallException( |
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'Attempt to read from a closed MaxMind DB.' |
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); |
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} |
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|
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return clone $this->metadata; |
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} |
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|
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/** |
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* Closes the MaxMind DB and returns resources to the system. |
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* |
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* @throws \Exception |
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* if an I/O error occurs |
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*/ |
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public function close(): void { |
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if ( \func_num_args() ) { |
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throw new \ArgumentCountError( |
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sprintf( '%s() expects exactly 0 parameters, %d given', __METHOD__, \func_num_args() ) |
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); |
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} |
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|
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if ( ! \is_resource( $this->fileHandle ) ) { |
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throw new \BadMethodCallException( |
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'Attempt to close a closed MaxMind DB.' |
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); |
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} |
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fclose( $this->fileHandle ); |
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} |
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} |
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|
