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Replace HeaderBag attributes with simple Message properties #132

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merged 2 commits into from
Jul 9, 2019
Merged

Replace HeaderBag attributes with simple Message properties #132

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daca439
Remove record counts from header bag and use current count instead
clue Jul 9, 2019
b1453be
Use message properties instead of header bag attributes
clue Jul 9, 2019
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54 changes: 0 additions & 54 deletions src/Model/HeaderBag.php
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106 changes: 58 additions & 48 deletions src/Model/Message.php
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,11 @@

use React\Dns\Query\Query;

/**
* This class represents an outgoing query message or an incoming response message
*
* @link https://tools.ietf.org/html/rfc1035#section-4.1.1
*/
class Message
{
const TYPE_A = 1;
Expand Down Expand Up @@ -39,10 +44,9 @@ class Message
public static function createRequestForQuery(Query $query)
{
$request = new Message();
$request->header->set('id', self::generateId());
$request->header->set('rd', 1);
$request->id = self::generateId();
$request->rd = true;
$request->questions[] = $query;
$request->prepare();

return $request;
}
Expand All @@ -57,20 +61,16 @@ public static function createRequestForQuery(Query $query)
public static function createResponseWithAnswersForQuery(Query $query, array $answers)
{
$response = new Message();
$response->header->set('id', self::generateId());
$response->header->set('qr', 1);
$response->header->set('opcode', Message::OPCODE_QUERY);
$response->header->set('rd', 1);
$response->header->set('rcode', Message::RCODE_OK);
$response->id = self::generateId();
$response->qr = true;
$response->rd = true;

$response->questions[] = $query;

foreach ($answers as $record) {
$response->answers[] = $record;
}

$response->prepare();

return $response;
}

Expand Down Expand Up @@ -101,9 +101,55 @@ private static function generateId()
}

/**
* @var HeaderBag
* The 16 bit message ID
*
* The response message ID has to match the request message ID. This allows
* the receiver to verify this is the correct response message. An outside
* attacker may try to inject fake responses by "guessing" the message ID,
* so this should use a proper CSPRNG to avoid possible cache poisoning.
*
* @var int 16 bit message ID
* @see self::generateId()
*/
public $id = 0;

/**
* @var bool Query/Response flag, query=false or response=true
*/
public $qr = false;

/**
* @var int specifies the kind of query (4 bit), see self::OPCODE_* constants
* @see self::OPCODE_QUERY
*/
public $header;
public $opcode = self::OPCODE_QUERY;

/**
*
* @var bool Authoritative Answer
*/
public $aa = false;

/**
* @var bool TrunCation
*/
public $tc = false;

/**
* @var bool Recursion Desired
*/
public $rd = false;

/**
* @var bool Recursion Available
*/
public $ra = false;

/**
* @var int response code (4 bit), see self::RCODE_* constants
* @see self::RCODE_OK
*/
public $rcode = Message::RCODE_OK;

/**
* An array of Query objects
Expand Down Expand Up @@ -136,40 +182,4 @@ private static function generateId()
* @var Record[]
*/
public $additional = array();

public function __construct()
{
$this->header = new HeaderBag();
}

/**
* Returns the 16 bit message ID
*
* The response message ID has to match the request message ID. This allows
* the receiver to verify this is the correct response message. An outside
* attacker may try to inject fake responses by "guessing" the message ID,
* so this should use a proper CSPRNG to avoid possible cache poisoning.
*
* @return int
* @see self::generateId()
*/
public function getId()
{
return $this->header->get('id');
}

/**
* Returns the response code (RCODE)
*
* @return int see self::RCODE_* constants
*/
public function getResponseCode()
{
return $this->header->get('rcode');
}

public function prepare()
{
$this->header->populateCounts($this);
}
}
31 changes: 15 additions & 16 deletions src/Protocol/BinaryDumper.php
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,6 @@

namespace React\Dns\Protocol;

use React\Dns\Model\HeaderBag;
use React\Dns\Model\Message;
use React\Dns\Model\Record;
use React\Dns\Query\Query;
Expand All @@ -17,7 +16,7 @@ public function toBinary(Message $message)
{
$data = '';

$data .= $this->headerToBinary($message->header);
$data .= $this->headerToBinary($message);
$data .= $this->questionToBinary($message->questions);
$data .= $this->recordsToBinary($message->answers);
$data .= $this->recordsToBinary($message->authority);
Expand All @@ -30,28 +29,28 @@ public function toBinary(Message $message)
* @param Message $message
* @return string
*/
private function headerToBinary(HeaderBag $header)
private function headerToBinary(Message $message)
{
$data = '';

$data .= pack('n', $header->get('id'));
$data .= pack('n', $message->id);

$flags = 0x00;
$flags = ($flags << 1) | $header->get('qr');
$flags = ($flags << 4) | $header->get('opcode');
$flags = ($flags << 1) | $header->get('aa');
$flags = ($flags << 1) | $header->get('tc');
$flags = ($flags << 1) | $header->get('rd');
$flags = ($flags << 1) | $header->get('ra');
$flags = ($flags << 3) | $header->get('z');
$flags = ($flags << 4) | $header->get('rcode');
$flags = ($flags << 1) | ($message->qr ? 1 : 0);
$flags = ($flags << 4) | $message->opcode;
$flags = ($flags << 1) | ($message->aa ? 1 : 0);
$flags = ($flags << 1) | ($message->tc ? 1 : 0);
$flags = ($flags << 1) | ($message->rd ? 1 : 0);
$flags = ($flags << 1) | ($message->ra ? 1 : 0);
$flags = ($flags << 3) | 0; // skip unused zero bit
$flags = ($flags << 4) | $message->rcode;

$data .= pack('n', $flags);

$data .= pack('n', $header->get('qdCount'));
$data .= pack('n', $header->get('anCount'));
$data .= pack('n', $header->get('nsCount'));
$data .= pack('n', $header->get('arCount'));
$data .= pack('n', count($message->questions));
$data .= pack('n', count($message->answers));
$data .= pack('n', count($message->authority));
$data .= pack('n', count($message->additional));

return $data;
}
Expand Down
74 changes: 28 additions & 46 deletions src/Protocol/Parser.php
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Original file line number Diff line number Diff line change
Expand Up @@ -39,20 +39,34 @@ public function parseMessage($data)

private function parse($data, Message $message)
{
if (!$message->header->get('id')) {
if (!$this->parseHeader($message)) {
return;
}
if (!isset($message->data[12 - 1])) {
return;
}

if ($message->header->get('qdCount') != count($message->questions)) {
if (!$this->parseQuestion($message)) {
list($id, $fields, $qdCount, $anCount, $nsCount, $arCount) = array_values(unpack('n*', substr($message->data, 0, 12)));
$message->consumed += 12;

$message->id = $id;
$message->rcode = $fields & 0xf;
$message->ra = (($fields >> 7) & 1) === 1;
$message->rd = (($fields >> 8) & 1) === 1;
$message->tc = (($fields >> 9) & 1) === 1;
$message->aa = (($fields >> 10) & 1) === 1;
$message->opcode = ($fields >> 11) & 0xf;
$message->qr = (($fields >> 15) & 1) === 1;

// parse all questions
for ($i = $qdCount; $i > 0; --$i) {
$question = $this->parseQuestion($message);
if ($question === null) {
return;
} else {
$message->questions[] = $question;
}
}

// parse all answer records
for ($i = $message->header->get('anCount'); $i > 0; --$i) {
for ($i = $anCount; $i > 0; --$i) {
$record = $this->parseRecord($message);
if ($record === null) {
return;
Expand All @@ -62,7 +76,7 @@ private function parse($data, Message $message)
}

// parse all authority records
for ($i = $message->header->get('nsCount'); $i > 0; --$i) {
for ($i = $nsCount; $i > 0; --$i) {
$record = $this->parseRecord($message);
if ($record === null) {
return;
Expand All @@ -72,7 +86,7 @@ private function parse($data, Message $message)
}

// parse all additional records
for ($i = $message->header->get('arCount'); $i > 0; --$i) {
for ($i = $arCount; $i > 0; --$i) {
$record = $this->parseRecord($message);
if ($record === null) {
return;
Expand All @@ -84,36 +98,10 @@ private function parse($data, Message $message)
return $message;
}

private function parseHeader(Message $message)
{
if (!isset($message->data[12 - 1])) {
return;
}

$header = substr($message->data, 0, 12);
$message->consumed += 12;

list($id, $fields, $qdCount, $anCount, $nsCount, $arCount) = array_values(unpack('n*', $header));

$rcode = $fields & bindec('1111');
$z = ($fields >> 4) & bindec('111');
$ra = ($fields >> 7) & 1;
$rd = ($fields >> 8) & 1;
$tc = ($fields >> 9) & 1;
$aa = ($fields >> 10) & 1;
$opcode = ($fields >> 11) & bindec('1111');
$qr = ($fields >> 15) & 1;

$vars = compact('id', 'qdCount', 'anCount', 'nsCount', 'arCount',
'qr', 'opcode', 'aa', 'tc', 'rd', 'ra', 'z', 'rcode');

foreach ($vars as $name => $value) {
$message->header->set($name, $value);
}

return $message;
}

/**
* @param Message $message
* @return ?Query
*/
private function parseQuestion(Message $message)
{
$consumed = $message->consumed;
Expand All @@ -129,17 +117,11 @@ private function parseQuestion(Message $message)

$message->consumed = $consumed;

$message->questions[] = new Query(
return new Query(
implode('.', $labels),
$type,
$class
);

if ($message->header->get('qdCount') != count($message->questions)) {
return $this->parseQuestion($message);
}

return $message;
}

/**
Expand Down
2 changes: 1 addition & 1 deletion src/Query/CachingExecutor.php
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,7 @@ function ($message) use ($nameserver, $query, $id, $cache, $executor, &$pending,
return $pending = $executor->query($nameserver, $query)->then(
function (Message $message) use ($cache, $id, $that) {
// DNS response message received => store in cache when not truncated and return
if (!$message->header->isTruncated()) {
if (!$message->tc) {
$cache->set($id, $message, $that->ttl($message));
}

Expand Down
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