/** * Encode the header section of the message * * @param \LibDNS\Encoder\EncodingContext $encodingContext * @param \LibDNS\Messages\Message $message * @return string * @throws \UnexpectedValueException When the header section is invalid */ private function encodeHeader(EncodingContext $encodingContext, Message $message) { $header = ['id' => $message->getID(), 'meta' => 0, 'qd' => $message->getQuestionRecords()->count(), 'an' => $message->getAnswerRecords()->count(), 'ns' => $message->getAuthorityRecords()->count(), 'ar' => $message->getAdditionalRecords()->count()]; $header['meta'] |= $message->getType() << 16; $header['meta'] |= $message->getOpCode() << 11; $header['meta'] |= (int) $message->isAuthoritative() << 10; $header['meta'] |= (int) $encodingContext->isTruncated() << 9; $header['meta'] |= (int) $message->isRecursionDesired() << 8; $header['meta'] |= (int) $message->isRecursionAvailable() << 7; $header['meta'] |= $message->getResponseCode(); return pack('n*', $header['id'], $header['meta'], $header['qd'], $header['an'], $header['ns'], $header['ar']); }
/** * Decode the header section of the message * * @param \LibDNS\Decoder\DecodingContext $decodingContext * @param \LibDNS\Messages\Message $message * @throws \UnexpectedValueException When the header section is invalid */ private function decodeHeader(DecodingContext $decodingContext, Message $message) { $header = unpack('nid/nmeta/nqd/nan/nns/nar', $this->readDataFromPacket($decodingContext->getPacket(), 12)); if (!$header) { throw new \UnexpectedValueException('Decode error: Header unpack failed'); } $message->setID($header['id']); $message->setType(($header['meta'] & 0b1000000000000000) >> 15); $message->setOpCode(($header['meta'] & 0b111100000000000) >> 11); $message->isAuthoritative(($header['meta'] & 0b10000000000) >> 10); $message->isTruncated(($header['meta'] & 0b1000000000) >> 9); $message->isRecursionDesired(($header['meta'] & 0b100000000) >> 8); $message->isRecursionAvailable(($header['meta'] & 0b10000000) >> 7); $message->setResponseCode($header['meta'] & 0b1111); $decodingContext->setExpectedQuestionRecords($header['qd']); $decodingContext->setExpectedAnswerRecords($header['an']); $decodingContext->setExpectedAuthorityRecords($header['ns']); $decodingContext->setExpectedAdditionalRecords($header['ar']); }