hosts = $hosts;
$this->fallback = $fallback;
}
public function query(Query $query)
{
if ($query->class === Message::CLASS_IN && ($query->type === Message::TYPE_A || $query->type === Message::TYPE_AAAA)) {
// forward lookup for type A or AAAA
$records = array();
$expectsColon = $query->type === Message::TYPE_AAAA;
foreach ($this->hosts->getIpsForHost($query->name) as $ip) {
// ensure this is an IPv4/IPV6 address according to query type
if ((strpos($ip, ':') !== false) === $expectsColon) {
$records[] = new Record($query->name, $query->type, $query->class, 0, $ip);
}
}
if ($records) {
return Promise\resolve(
Message::createResponseWithAnswersForQuery($query, $records)
);
}
} elseif ($query->class === Message::CLASS_IN && $query->type === Message::TYPE_PTR) {
// reverse lookup: extract IPv4 or IPv6 from special `.arpa` domain
$ip = $this->getIpFromHost($query->name);
if ($ip !== null) {
$records = array();
foreach ($this->hosts->getHostsForIp($ip) as $host) {
$records[] = new Record($query->name, $query->type, $query->class, 0, $host);
}
if ($records) {
return Promise\resolve(
Message::createResponseWithAnswersForQuery($query, $records)
);
}
}
}
return $this->fallback->query($query);
}
private function getIpFromHost($host)
{
if (substr($host, -13) === '.in-addr.arpa') {
// IPv4: read as IP and reverse bytes
$ip = @inet_pton(substr($host, 0, -13));
if ($ip === false || isset($ip[4])) {
return null;
}
return inet_ntop(strrev($ip));
} elseif (substr($host, -9) === '.ip6.arpa') {
// IPv6: replace dots, reverse nibbles and interpret as hexadecimal string
$ip = @inet_ntop(pack('H*', strrev(str_replace('.', '', substr($host, 0, -9)))));
if ($ip === false) {
return null;
}
return $ip;
} else {
return null;
}
}
}