vichan/inc/Data/Driver/Dns/LibcDnsDriver.php

51 lines
1.2 KiB
PHP

<?php
namespace Vichan\Data\Driver\Dns;
/**
* For the love of god never use this implementation if you can.
*/
class LibcDnsDriver implements DnsDriver {
public function __construct(int $timeout) {
// Try to impose a very frail timeout https://www.php.net/manual/en/function.gethostbyname.php#118841
\putenv("RES_OPTIONS=retrans:1 retry:1 timeout:{$timeout} attempts:1");
}
public function nameToIPs(string $name): ?array {
$ret = \dns_get_record($name, DNS_A | DNS_AAAA);
if ($ret === false) {
return null;
}
$ips = [];
foreach ($ret as $dns_record) {
if ($dns_record['type'] == 'A') {
$ips[] = $dns_record['ip'];
} elseif ($dns_record['type'] == 'AAAA') {
$ips[] = $dns_record['ipv6'];
}
}
if (empty($ips)) {
return [];
} else {
// Stable return order.
\sort($ips, \SORT_STRING);
return $ips;
}
}
/**
* For the love of god never use this.
* https://www.php.net/manual/en/function.gethostbyaddr.php#57553
*/
public function IPToNames(string $ip): ?array {
$ret = \gethostbyaddr($ip);
if ($ret === $ip || $ret === false) {
return null;
}
// Case extravaganza: https://www.php.net/manual/en/function.gethostbyaddr.php#123563
return [ \strtolower($ret) ];
}
}