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See Release Notes

  • Bug fixes for general core bugs in 4.0.x will end 8 May 2023 (12 months).
  • Bug fixes for security issues in 4.0.x will end 13 November 2023 (18 months).
  • PHP version: minimum PHP 7.3.0 Note: the minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is also supported.
<?php

declare(strict_types=1);

namespace MaxMind\Db;

use ArgumentCountError;
use BadMethodCallException;
use Exception;
use InvalidArgumentException;
use MaxMind\Db\Reader\Decoder;
use MaxMind\Db\Reader\InvalidDatabaseException;
use MaxMind\Db\Reader\Metadata;
use MaxMind\Db\Reader\Util;
use UnexpectedValueException;

/**
 * Instances of this class provide a reader for the MaxMind DB format. IP
 * addresses can be looked up using the get method.
 */
class Reader
{
    /**
     * @var int
     */
    private static $DATA_SECTION_SEPARATOR_SIZE = 16;
    /**
     * @var string
     */
    private static $METADATA_START_MARKER = "\xAB\xCD\xEFMaxMind.com";
    /**
     * @var int
     */
    private static $METADATA_START_MARKER_LENGTH = 14;
    /**
     * @var int
     */
    private static $METADATA_MAX_SIZE = 131072; // 128 * 1024 = 128KiB

    /**
     * @var Decoder
     */
    private $decoder;
    /**
     * @var resource
     */
    private $fileHandle;
    /**
     * @var int
     */
    private $fileSize;
    /**
     * @var int
     */
    private $ipV4Start;
    /**
     * @var Metadata
     */
    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 InvalidDatabaseException
     *                                  if the database is invalid or there is an error reading
     *                                  from it
     */
    public function __construct(string $database)
    {
        if (\func_num_args() !== 1) {
            throw new ArgumentCountError(
                sprintf('%s() expects exactly 1 parameter, %d given', __METHOD__, \func_num_args())
            );
        }

        $fileHandle = @fopen($database, 'rb');
        if ($fileHandle === false) {
            throw new InvalidArgumentException(
                "The file \"$database\" does not exist or is not readable."
            );
        }
        $this->fileHandle = $fileHandle;

        $fileSize = @filesize($database);
        if ($fileSize === false) {
            throw new UnexpectedValueException(
                "Error determining the size of \"$database\"."
            );
        }
        $this->fileSize = $fileSize;

        $start = $this->findMetadataStart($database);
        $metadataDecoder = new Decoder($this->fileHandle, $start);
        [$metadataArray] = $metadataDecoder->decode($start);
        $this->metadata = new Metadata($metadataArray);
        $this->decoder = new Decoder(
            $this->fileHandle,
            $this->metadata->searchTreeSize + self::$DATA_SECTION_SEPARATOR_SIZE
        );
        $this->ipV4Start = $this->ipV4StartNode();
    }

    /**
     * Retrieves the record for the IP address.
     *
     * @param string $ipAddress
     *                          the IP address to look up
     *
     * @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
     *
     * @return mixed the record for the IP address
     */
    public function get(string $ipAddress)
    {
        if (\func_num_args() !== 1) {
            throw new ArgumentCountError(
                sprintf('%s() expects exactly 1 parameter, %d given', __METHOD__, \func_num_args())
            );
        }
        [$record] = $this->getWithPrefixLen($ipAddress);

        return $record;
    }

    /**
     * Retrieves the record for the IP address and its associated network prefix length.
     *
     * @param string $ipAddress
     *                          the IP address to look up
     *
     * @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
     *
     * @return array an array where the first element is the record and the
     *               second the network prefix length for the record
     */
    public function getWithPrefixLen(string $ipAddress): array
    {
        if (\func_num_args() !== 1) {
            throw new ArgumentCountError(
                sprintf('%s() expects exactly 1 parameter, %d given', __METHOD__, \func_num_args())
            );
        }

        if (!\is_resource($this->fileHandle)) {
            throw new BadMethodCallException(
                'Attempt to read from a closed MaxMind DB.'
            );
        }

        [$pointer, $prefixLen] = $this->findAddressInTree($ipAddress);
        if ($pointer === 0) {
            return [null, $prefixLen];
        }

        return [$this->resolveDataPointer($pointer), $prefixLen];
    }

    private function findAddressInTree(string $ipAddress): array
    {
        $packedAddr = @inet_pton($ipAddress);
        if ($packedAddr === false) {
            throw new InvalidArgumentException(
                "The value \"$ipAddress\" is not a valid IP address."
            );
        }

        $rawAddress = unpack('C*', $packedAddr);

        $bitCount = \count($rawAddress) * 8;

        // The first node of the tree is always node 0, at the beginning of the
        // value
        $node = 0;

        $metadata = $this->metadata;

        // 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 ($metadata->ipVersion === 6) {
            if ($bitCount === 32) {
                $node = $this->ipV4Start;
            }
        } elseif ($metadata->ipVersion === 4 && $bitCount === 128) {
            throw new InvalidArgumentException(
                "Error looking up $ipAddress. You attempted to look up an"
                . ' IPv6 address in an IPv4-only database.'
            );
        }

        $nodeCount = $metadata->nodeCount;

        for ($i = 0; $i < $bitCount && $node < $nodeCount; ++$i) {
            $tempBit = 0xFF & $rawAddress[($i >> 3) + 1];
            $bit = 1 & ($tempBit >> 7 - ($i % 8));

            $node = $this->readNode($node, $bit);
        }
        if ($node === $nodeCount) {
            // Record is empty
            return [0, $i];
< } elseif ($node > $nodeCount) {
> } > if ($node > $nodeCount) {
// Record is a data pointer return [$node, $i]; }
>
throw new InvalidDatabaseException( 'Invalid or corrupt database. Maximum search depth reached without finding a leaf node' ); } private function ipV4StartNode(): int { // If we have an IPv4 database, the start node is the first node if ($this->metadata->ipVersion === 4) { return 0; } $node = 0; for ($i = 0; $i < 96 && $node < $this->metadata->nodeCount; ++$i) { $node = $this->readNode($node, 0); } return $node; } private function readNode(int $nodeNumber, int $index): int { $baseOffset = $nodeNumber * $this->metadata->nodeByteSize; switch ($this->metadata->recordSize) { case 24: $bytes = Util::read($this->fileHandle, $baseOffset + $index * 3, 3); [, $node] = unpack('N', "\x00" . $bytes); return $node;
>
case 28: $bytes = Util::read($this->fileHandle, $baseOffset + 3 * $index, 4); if ($index === 0) { $middle = (0xF0 & \ord($bytes[3])) >> 4; } else { $middle = 0x0F & \ord($bytes[0]); } [, $node] = unpack('N', \chr($middle) . substr($bytes, $index, 3)); return $node;
>
case 32: $bytes = Util::read($this->fileHandle, $baseOffset + $index * 4, 4); [, $node] = unpack('N', $bytes); return $node;
>
default: throw new InvalidDatabaseException( 'Unknown record size: ' . $this->metadata->recordSize ); } } /** * @return mixed */ private function resolveDataPointer(int $pointer) { $resolved = $pointer - $this->metadata->nodeCount + $this->metadata->searchTreeSize; if ($resolved >= $this->fileSize) { throw new InvalidDatabaseException( "The MaxMind DB file's search tree is corrupt" ); } [$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(string $filename): int { $handle = $this->fileHandle; $fstat = fstat($handle); $fileSize = $fstat['size']; $marker = self::$METADATA_START_MARKER; $markerLength = self::$METADATA_START_MARKER_LENGTH; $minStart = $fileSize - min(self::$METADATA_MAX_SIZE, $fileSize); for ($offset = $fileSize - $markerLength; $offset >= $minStart; --$offset) { if (fseek($handle, $offset) !== 0) { break; } $value = fread($handle, $markerLength); if ($value === $marker) { return $offset + $markerLength; } }
>
throw new InvalidDatabaseException( "Error opening database file ($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(): Metadata { if (\func_num_args()) { throw new ArgumentCountError( sprintf('%s() expects exactly 0 parameters, %d given', __METHOD__, \func_num_args()) ); } // 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 clone $this->metadata; } /** * Closes the MaxMind DB and returns resources to the system. * * @throws Exception * if an I/O error occurs */ public function close(): void { if (\func_num_args()) { throw new ArgumentCountError( sprintf('%s() expects exactly 0 parameters, %d given', __METHOD__, \func_num_args()) ); } if (!\is_resource($this->fileHandle)) { throw new BadMethodCallException( 'Attempt to close a closed MaxMind DB.' ); } fclose($this->fileHandle); } }