/**
* Decode a DomainName field
*
* @param \LibDNS\Decoder\DecodingContext $decodingContext
* @param \LibDNS\Records\Types\DomainName $domainName The object to populate with the result
* @return int The number of packet bytes consumed by the operation
* @throws \UnexpectedValueException When the packet data is invalid
*/
private function decodeDomainName(DecodingContext $decodingContext, DomainName $domainName)
{
$packet = $decodingContext->getPacket();
$startIndex = '0x' . dechex($packet->getPointer());
$labelRegistry = $decodingContext->getLabelRegistry();
$labels = [];
$totalLength = 0;
while (++$totalLength && ($length = ord($this->readDataFromPacket($packet, 1)))) {
$labelType = $length & 0b11000000;
if ($labelType === 0b0) {
$index = $packet->getPointer() - 1;
$label = $this->readDataFromPacket($packet, $length);
array_unshift($labels, [$index, $label]);
$totalLength += $length;
} else {
if ($labelType === 0b11000000) {
$index = ($length & 0b111111) << 8 | ord($this->readDataFromPacket($packet, 1));
$ref = $labelRegistry->lookupLabel($index);
if ($ref === null) {
throw new \UnexpectedValueException('Decode error: Invalid compression pointer reference in domain name at position ' . $startIndex);
}
array_unshift($labels, $ref);
$totalLength++;
break;
} else {
throw new \UnexpectedValueException('Decode error: Invalid label type ' . $labelType . 'in domain name at position ' . $startIndex);
}
}
}
if (!$labels) {
throw new \UnexpectedValueException('Decode error: Empty domain name at position ' . $startIndex);
}
$result = [];
foreach ($labels as $label) {
if (is_int($label[0])) {
array_unshift($result, $label[1]);
$labelRegistry->register($result, $label[0]);
} else {
$result = $label;
}
}
$domainName->setLabels($result);
return $totalLength;
}
/**
* Encode a DomainName field
*
* @param \LibDNS\Records\Types\DomainName $domainName
* @param \LibDNS\Encoder\EncodingContext $encodingContext
* @return string
*/
private function encodeDomainName(DomainName $domainName, EncodingContext $encodingContext)
{
$packetIndex = $encodingContext->getPacket()->getLength() + 12;
$labelRegistry = $encodingContext->getLabelRegistry();
$result = '';
$labels = $domainName->getLabels();
if ($encodingContext->useCompression()) {
do {
$part = implode('.', $labels);
$index = $labelRegistry->lookupIndex($part);
if ($index === null) {
$labelRegistry->register($part, $packetIndex);
$label = array_shift($labels);
$length = strlen($label);
$result .= chr($length) . $label;
$packetIndex += $length + 1;
} else {
$result .= pack('n', 0b1100000000000000 | $index);
break;
}
} while ($labels);
if (!$labels) {
$result .= "";
}
} else {
foreach ($labels as $label) {
$result .= chr(strlen($label)) . $label;
}
$result .= "";
}
return $result;
}
