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Refactor Parser to avoid assigning dynamic properties (PHP 8.2+ compatibility) #186

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Merged
WyriHaximus merged 1 commit into from
Nov 26, 2021
Merged

Refactor Parser to avoid assigning dynamic properties (PHP 8.2+ compatibility) #186

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150 changes: 75 additions & 75 deletions src/Protocol/Parser.php
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Original file line number Diff line number Diff line change
Expand Up @@ -23,29 +23,28 @@ final class Parser
*/
public function parseMessage($data)
{
// create empty message with two additional, temporary properties for parser
$message = new Message();
$message->data = $data;
$message->consumed = null;

if ($this->parse($data, $message) !== $message) {
$message = $this->parse($data, 0);
if ($message === null) {
throw new InvalidArgumentException('Unable to parse binary message');
}

unset($message->data, $message->consumed);

return $message;
}

private function parse($data, Message $message)
/**
* @param string $data
* @param int $consumed
* @return ?Message
*/
private function parse($data, $consumed)
{
if (!isset($message->data[12 - 1])) {
return;
if (!isset($data[12 - 1])) {
return null;
}

list($id, $fields, $qdCount, $anCount, $nsCount, $arCount) = array_values(unpack('n*', substr($message->data, 0, 12)));
$message->consumed += 12;
list($id, $fields, $qdCount, $anCount, $nsCount, $arCount) = array_values(unpack('n*', substr($data, 0, 12)));

$message = new Message();
$message->id = $id;
$message->rcode = $fields & 0xf;
$message->ra = (($fields >> 7) & 1) === 1;
Expand All @@ -54,42 +53,43 @@ private function parse($data, Message $message)
$message->aa = (($fields >> 10) & 1) === 1;
$message->opcode = ($fields >> 11) & 0xf;
$message->qr = (($fields >> 15) & 1) === 1;
$consumed += 12;

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

// parse all answer records
for ($i = $anCount; $i > 0; --$i) {
$record = $this->parseRecord($message);
list($record, $consumed) = $this->parseRecord($data, $consumed);
if ($record === null) {
return;
return null;
} else {
$message->answers[] = $record;
}
}

// parse all authority records
for ($i = $nsCount; $i > 0; --$i) {
$record = $this->parseRecord($message);
list($record, $consumed) = $this->parseRecord($data, $consumed);
if ($record === null) {
return;
return null;
} else {
$message->authority[] = $record;
}
}

// parse all additional records
for ($i = $arCount; $i > 0; --$i) {
$record = $this->parseRecord($message);
list($record, $consumed) = $this->parseRecord($data, $consumed);
if ($record === null) {
return;
return null;
} else {
$message->additional[] = $record;
}
Expand All @@ -99,89 +99,88 @@ private function parse($data, Message $message)
}

/**
* @param Message $message
* @return ?Query
* @param string $data
* @param int $consumed
* @return array
*/
private function parseQuestion(Message $message)
private function parseQuestion($data, $consumed)
{
$consumed = $message->consumed;

list($labels, $consumed) = $this->readLabels($message->data, $consumed);
list($labels, $consumed) = $this->readLabels($data, $consumed);

if ($labels === null || !isset($message->data[$consumed + 4 - 1])) {
return;
if ($labels === null || !isset($data[$consumed + 4 - 1])) {
return array(null, null);
}

list($type, $class) = array_values(unpack('n*', substr($message->data, $consumed, 4)));
list($type, $class) = array_values(unpack('n*', substr($data, $consumed, 4)));
$consumed += 4;

$message->consumed = $consumed;

return new Query(
implode('.', $labels),
$type,
$class
return array(
new Query(
implode('.', $labels),
$type,
$class
),
$consumed
);
}

/**
* @param Message $message
* @return ?Record returns parsed Record on success or null if data is invalid/incomplete
* @param string $data
* @param int $consumed
* @return array An array with a parsed Record on success or array with null if data is invalid/incomplete
*/
private function parseRecord(Message $message)
private function parseRecord($data, $consumed)
{
$consumed = $message->consumed;

list($name, $consumed) = $this->readDomain($message->data, $consumed);
list($name, $consumed) = $this->readDomain($data, $consumed);

if ($name === null || !isset($message->data[$consumed + 10 - 1])) {
return null;
if ($name === null || !isset($data[$consumed + 10 - 1])) {
return array(null, null);
}

list($type, $class) = array_values(unpack('n*', substr($message->data, $consumed, 4)));
list($type, $class) = array_values(unpack('n*', substr($data, $consumed, 4)));
$consumed += 4;

list($ttl) = array_values(unpack('N', substr($message->data, $consumed, 4)));
list($ttl) = array_values(unpack('N', substr($data, $consumed, 4)));
$consumed += 4;

// TTL is a UINT32 that must not have most significant bit set for BC reasons
if ($ttl < 0 || $ttl >= 1 << 31) {
$ttl = 0;
}

list($rdLength) = array_values(unpack('n', substr($message->data, $consumed, 2)));
list($rdLength) = array_values(unpack('n', substr($data, $consumed, 2)));
$consumed += 2;

if (!isset($message->data[$consumed + $rdLength - 1])) {
return null;
if (!isset($data[$consumed + $rdLength - 1])) {
return array(null, null);
}

$rdata = null;
$expected = $consumed + $rdLength;

if (Message::TYPE_A === $type) {
if ($rdLength === 4) {
$rdata = inet_ntop(substr($message->data, $consumed, $rdLength));
$rdata = inet_ntop(substr($data, $consumed, $rdLength));
$consumed += $rdLength;
}
} elseif (Message::TYPE_AAAA === $type) {
if ($rdLength === 16) {
$rdata = inet_ntop(substr($message->data, $consumed, $rdLength));
$rdata = inet_ntop(substr($data, $consumed, $rdLength));
$consumed += $rdLength;
}
} elseif (Message::TYPE_CNAME === $type || Message::TYPE_PTR === $type || Message::TYPE_NS === $type) {
list($rdata, $consumed) = $this->readDomain($message->data, $consumed);
list($rdata, $consumed) = $this->readDomain($data, $consumed);
} elseif (Message::TYPE_TXT === $type || Message::TYPE_SPF === $type) {
$rdata = array();
while ($consumed < $expected) {
$len = ord($message->data[$consumed]);
$rdata[] = (string)substr($message->data, $consumed + 1, $len);
$len = ord($data[$consumed]);
$rdata[] = (string)substr($data, $consumed + 1, $len);
$consumed += $len + 1;
}
} elseif (Message::TYPE_MX === $type) {
if ($rdLength > 2) {
list($priority) = array_values(unpack('n', substr($message->data, $consumed, 2)));
list($target, $consumed) = $this->readDomain($message->data, $consumed + 2);
list($priority) = array_values(unpack('n', substr($data, $consumed, 2)));
list($target, $consumed) = $this->readDomain($data, $consumed + 2);

$rdata = array(
'priority' => $priority,
Expand All @@ -190,8 +189,8 @@ private function parseRecord(Message $message)
}
} elseif (Message::TYPE_SRV === $type) {
if ($rdLength > 6) {
list($priority, $weight, $port) = array_values(unpack('n*', substr($message->data, $consumed, 6)));
list($target, $consumed) = $this->readDomain($message->data, $consumed + 6);
list($priority, $weight, $port) = array_values(unpack('n*', substr($data, $consumed, 6)));
list($target, $consumed) = $this->readDomain($data, $consumed + 6);

$rdata = array(
'priority' => $priority,
Expand All @@ -202,8 +201,8 @@ private function parseRecord(Message $message)
}
} elseif (Message::TYPE_SSHFP === $type) {
if ($rdLength > 2) {
list($algorithm, $hash) = \array_values(\unpack('C*', \substr($message->data, $consumed, 2)));
$fingerprint = \bin2hex(\substr($message->data, $consumed + 2, $rdLength - 2));
list($algorithm, $hash) = \array_values(\unpack('C*', \substr($data, $consumed, 2)));
$fingerprint = \bin2hex(\substr($data, $consumed + 2, $rdLength - 2));
$consumed += $rdLength;

$rdata = array(
Expand All @@ -213,11 +212,11 @@ private function parseRecord(Message $message)
);
}
} elseif (Message::TYPE_SOA === $type) {
list($mname, $consumed) = $this->readDomain($message->data, $consumed);
list($rname, $consumed) = $this->readDomain($message->data, $consumed);
list($mname, $consumed) = $this->readDomain($data, $consumed);
list($rname, $consumed) = $this->readDomain($data, $consumed);

if ($mname !== null && $rname !== null && isset($message->data[$consumed + 20 - 1])) {
list($serial, $refresh, $retry, $expire, $minimum) = array_values(unpack('N*', substr($message->data, $consumed, 20)));
if ($mname !== null && $rname !== null && isset($data[$consumed + 20 - 1])) {
list($serial, $refresh, $retry, $expire, $minimum) = array_values(unpack('N*', substr($data, $consumed, 20)));
$consumed += 20;

$rdata = array(
Expand All @@ -232,9 +231,9 @@ private function parseRecord(Message $message)
}
} elseif (Message::TYPE_OPT === $type) {
$rdata = array();
while (isset($message->data[$consumed + 4 - 1])) {
list($code, $length) = array_values(unpack('n*', substr($message->data, $consumed, 4)));
$value = (string) substr($message->data, $consumed + 4, $length);
while (isset($data[$consumed + 4 - 1])) {
list($code, $length) = array_values(unpack('n*', substr($data, $consumed, 4)));
$value = (string) substr($data, $consumed + 4, $length);
if ($code === Message::OPT_TCP_KEEPALIVE && $value === '') {
$value = null;
} elseif ($code === Message::OPT_TCP_KEEPALIVE && $length === 2) {
Expand All @@ -248,11 +247,11 @@ private function parseRecord(Message $message)
}
} elseif (Message::TYPE_CAA === $type) {
if ($rdLength > 3) {
list($flag, $tagLength) = array_values(unpack('C*', substr($message->data, $consumed, 2)));
list($flag, $tagLength) = array_values(unpack('C*', substr($data, $consumed, 2)));

if ($tagLength > 0 && $rdLength - 2 - $tagLength > 0) {
$tag = substr($message->data, $consumed + 2, $tagLength);
$value = substr($message->data, $consumed + 2 + $tagLength, $rdLength - 2 - $tagLength);
$tag = substr($data, $consumed + 2, $tagLength);
$value = substr($data, $consumed + 2 + $tagLength, $rdLength - 2 - $tagLength);
$consumed += $rdLength;

$rdata = array(
Expand All @@ -264,18 +263,19 @@ private function parseRecord(Message $message)
}
} else {
// unknown types simply parse rdata as an opaque binary string
$rdata = substr($message->data, $consumed, $rdLength);
$rdata = substr($data, $consumed, $rdLength);
$consumed += $rdLength;
}

// ensure parsing record data consumes expact number of bytes indicated in record length
if ($consumed !== $expected || $rdata === null) {
return null;
return array(null, null);
}

$message->consumed = $consumed;

return new Record($name, $type, $class, $ttl, $rdata);
return array(
new Record($name, $type, $class, $ttl, $rdata),
$consumed
);
}

private function readDomain($data, $consumed)
Expand Down