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<?php |
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/* |
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* This file is part of PHP DNS Server. |
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* |
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* (c) Yif Swery <[email protected]> |
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* |
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* For the full copyright and license information, please view the LICENSE |
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* file that was distributed with this source code. |
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*/ |
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namespace yswery\DNS; |
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class Encoder |
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{ |
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/** |
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* @param Message $message |
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* |
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* @return string |
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* |
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* @throws UnsupportedTypeException |
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*/ |
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public static function encodeMessage(Message $message): string |
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{ |
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return |
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self::encodeHeader($message->getHeader()). |
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self::encodeResourceRecords($message->getQuestions()). |
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self::encodeResourceRecords($message->getAnswers()). |
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self::encodeResourceRecords($message->getAuthoritatives()). |
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self::encodeResourceRecords($message->getAdditionals()); |
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} |
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/** |
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* Encode a domain name as a sequence of labels. |
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* |
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* @param $domain |
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* |
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* @return string |
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*/ |
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public static function encodeDomainName($domain): string |
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{ |
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if ('.' === $domain) { |
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return chr(0); |
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} |
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$domain = rtrim($domain, '.').'.'; |
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$res = ''; |
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foreach (explode('.', $domain) as $label) { |
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$res .= chr(strlen($label)).$label; |
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} |
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return $res; |
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} |
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/** |
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* @param ResourceRecord[] $resourceRecords |
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* |
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* @return string |
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* |
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* @throws UnsupportedTypeException |
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*/ |
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public static function encodeResourceRecords(array $resourceRecords): string |
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{ |
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$records = array_map('self::encodeResourceRecord', $resourceRecords); |
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return implode('', $records); |
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} |
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/** |
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* @param ResourceRecord $rr |
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* |
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* @return string |
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* |
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* @throws UnsupportedTypeException |
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*/ |
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public static function encodeResourceRecord(ResourceRecord $rr): string |
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{ |
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$encoded = self::encodeDomainName($rr->getName()); |
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if ($rr->isQuestion()) { |
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return $encoded.pack('nn', $rr->getType(), $rr->getClass()); |
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} |
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$data = RdataEncoder::encodeRdata($rr->getType(), $rr->getRdata()); |
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$encoded .= pack('nnNn', $rr->getType(), $rr->getClass(), $rr->getTtl(), strlen($data)); |
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return $encoded.$data; |
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} |
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/** |
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* @param Header $header |
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* |
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* @return string |
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*/ |
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public static function encodeHeader(Header $header): string |
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{ |
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return pack( |
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'nnnnnn', |
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$header->getId(), |
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self::encodeFlags($header), |
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$header->getQuestionCount(), |
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$header->getAnswerCount(), |
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$header->getNameServerCount(), |
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$header->getAdditionalRecordsCount() |
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); |
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} |
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/** |
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* Encode the bit field of the Header between "ID" and "QDCOUNT". |
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* |
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* @param Header $header |
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* |
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* @return int |
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*/ |
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private static function encodeFlags(Header $header): int |
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{ |
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return 0x0 | |
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($header->isResponse() & 0x1) << 15 | |
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($header->getOpcode() & 0xf) << 11 | |
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($header->isAuthoritative() & 0x1) << 10 | |
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($header->isTruncated() & 0x1) << 9 | |
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($header->isRecursionDesired() & 0x1) << 8 | |
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($header->isRecursionAvailable() & 0x1) << 7 | |
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($header->getZ() & 0x7) << 4 | |
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($header->getRcode() & 0xf); |
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} |
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} |
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samuelwilliams /
PHP-DNS-SERVER
