|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
/* |
|
4
|
|
|
* This file is part of PHP DNS Server. |
|
5
|
|
|
* |
|
6
|
|
|
* (c) Yif Swery <[email protected]> |
|
7
|
|
|
* |
|
8
|
|
|
* For the full copyright and license information, please view the LICENSE |
|
9
|
|
|
* file that was distributed with this source code. |
|
10
|
|
|
*/ |
|
11
|
|
|
|
|
12
|
|
|
namespace yswery\DNS; |
|
13
|
|
|
|
|
14
|
|
|
class Decoder |
|
15
|
|
|
{ |
|
16
|
|
|
/** |
|
17
|
|
|
* @param string $message |
|
18
|
|
|
* |
|
19
|
|
|
* @return Message |
|
20
|
|
|
*/ |
|
21
|
7 |
|
public static function decodeMessage(string $message): Message |
|
22
|
|
|
{ |
|
23
|
7 |
|
$offset = 0; |
|
24
|
7 |
|
$header = self::decodeHeader($message, $offset); |
|
25
|
7 |
|
$messageObject = new Message($header); |
|
26
|
7 |
|
$messageObject->setQuestions(self::decodeResourceRecords($message, $header->getQuestionCount(), $offset, true)); |
|
27
|
7 |
|
$messageObject->setAnswers(self::decodeResourceRecords($message, $header->getAnswerCount(), $offset)); |
|
28
|
7 |
|
$messageObject->setAuthoritatives(self::decodeResourceRecords($message, $header->getNameServerCount(), $offset)); |
|
29
|
7 |
|
$messageObject->setAdditionals(self::decodeResourceRecords($message, $header->getAdditionalRecordsCount(), $offset)); |
|
30
|
|
|
|
|
31
|
7 |
|
return $messageObject; |
|
32
|
|
|
} |
|
33
|
|
|
|
|
34
|
|
|
/** |
|
35
|
|
|
* @param string $string |
|
36
|
|
|
* @param int $offset |
|
37
|
|
|
* |
|
38
|
|
|
* @return string |
|
39
|
|
|
*/ |
|
40
|
11 |
|
public static function decodeDomainName(string $string, int &$offset = 0): string |
|
41
|
|
|
{ |
|
42
|
11 |
|
$len = ord($string[$offset]); |
|
43
|
11 |
|
++$offset; |
|
44
|
|
|
|
|
45
|
11 |
|
if (0 === $len) { |
|
46
|
1 |
|
return '.'; |
|
47
|
|
|
} |
|
48
|
|
|
|
|
49
|
11 |
|
$domainName = ''; |
|
50
|
11 |
|
while (0 !== $len) { |
|
51
|
11 |
|
$domainName .= substr($string, $offset, $len).'.'; |
|
52
|
11 |
|
$offset += $len; |
|
53
|
11 |
|
$len = ord($string[$offset]); |
|
54
|
11 |
|
++$offset; |
|
55
|
|
|
} |
|
56
|
|
|
|
|
57
|
11 |
|
return $domainName; |
|
58
|
|
|
} |
|
59
|
|
|
|
|
60
|
|
|
/** |
|
61
|
|
|
* @param string $pkt |
|
62
|
|
|
* @param int $offset |
|
63
|
|
|
* @param int $count The number of resource records to decode |
|
64
|
|
|
* @param bool $isQuestion Is the resource record from the question section |
|
65
|
|
|
* |
|
66
|
|
|
* @return ResourceRecord[] |
|
67
|
|
|
*/ |
|
68
|
9 |
|
public static function decodeResourceRecords(string $pkt, int $count = 1, int &$offset = 0, bool $isQuestion = false): array |
|
69
|
|
|
{ |
|
70
|
9 |
|
$resourceRecords = []; |
|
71
|
|
|
|
|
72
|
9 |
|
for ($i = 0; $i < $count; ++$i) { |
|
73
|
8 |
|
($rr = new ResourceRecord()) |
|
74
|
8 |
|
->setQuestion($isQuestion) |
|
75
|
8 |
|
->setName(self::decodeDomainName($pkt, $offset)); |
|
76
|
|
|
|
|
77
|
8 |
|
if ($rr->isQuestion()) { |
|
78
|
7 |
|
$values = unpack('ntype/nclass', substr($pkt, $offset, 4)); |
|
79
|
7 |
|
$rr->setType($values['type'])->setClass($values['class']); |
|
80
|
7 |
|
$offset += 4; |
|
81
|
|
|
} else { |
|
82
|
4 |
|
$values = unpack('ntype/nclass/Nttl/ndlength', substr($pkt, $offset, 10)); |
|
83
|
4 |
|
$rr->setType($values['type'])->setClass($values['class'])->setTtl($values['ttl']); |
|
84
|
4 |
|
$offset += 10; |
|
85
|
|
|
|
|
86
|
|
|
//Ignore unsupported types. |
|
87
|
|
|
try { |
|
88
|
4 |
|
$rr->setRdata(RdataDecoder::decodeRdata($rr->getType(), substr($pkt, $offset, $values['dlength']))); |
|
89
|
|
|
} catch (UnsupportedTypeException $e) { |
|
90
|
|
|
$offset += $values['dlength']; |
|
91
|
|
|
continue; |
|
92
|
|
|
} |
|
93
|
4 |
|
$offset += $values['dlength']; |
|
94
|
|
|
} |
|
95
|
|
|
|
|
96
|
8 |
|
$resourceRecords[] = $rr; |
|
97
|
|
|
} |
|
98
|
|
|
|
|
99
|
9 |
|
return $resourceRecords; |
|
100
|
|
|
} |
|
101
|
|
|
|
|
102
|
|
|
/** |
|
103
|
|
|
* @param string $pkt |
|
104
|
|
|
* @param int $offset |
|
105
|
|
|
* |
|
106
|
|
|
* @return Header |
|
107
|
|
|
*/ |
|
108
|
8 |
|
public static function decodeHeader(string $pkt, int &$offset = 0): Header |
|
109
|
|
|
{ |
|
110
|
8 |
|
$data = unpack('nid/nflags/nqdcount/nancount/nnscount/narcount', $pkt); |
|
111
|
8 |
|
$flags = self::decodeFlags($data['flags']); |
|
112
|
8 |
|
$offset += 12; |
|
113
|
|
|
|
|
114
|
8 |
|
return (new Header()) |
|
115
|
8 |
|
->setId($data['id']) |
|
116
|
8 |
|
->setResponse($flags['qr']) |
|
117
|
8 |
|
->setOpcode($flags['opcode']) |
|
118
|
8 |
|
->setAuthoritative($flags['aa']) |
|
119
|
8 |
|
->setTruncated($flags['tc']) |
|
120
|
8 |
|
->setRecursionDesired($flags['rd']) |
|
121
|
8 |
|
->setRecursionAvailable($flags['ra']) |
|
122
|
8 |
|
->setZ($flags['z']) |
|
123
|
8 |
|
->setRcode($flags['rcode']) |
|
124
|
8 |
|
->setQuestionCount($data['qdcount']) |
|
125
|
8 |
|
->setAnswerCount($data['ancount']) |
|
126
|
8 |
|
->setNameServerCount($data['nscount']) |
|
127
|
8 |
|
->setAdditionalRecordsCount($data['arcount']); |
|
128
|
|
|
} |
|
129
|
|
|
|
|
130
|
|
|
/** |
|
131
|
|
|
* @param string $flags |
|
132
|
|
|
* |
|
133
|
|
|
* @return array |
|
134
|
|
|
*/ |
|
135
|
8 |
|
private static function decodeFlags($flags): array |
|
136
|
|
|
{ |
|
137
|
|
|
return [ |
|
138
|
8 |
|
'qr' => $flags >> 15 & 0x1, |
|
139
|
8 |
|
'opcode' => $flags >> 11 & 0xf, |
|
140
|
8 |
|
'aa' => $flags >> 10 & 0x1, |
|
141
|
8 |
|
'tc' => $flags >> 9 & 0x1, |
|
142
|
8 |
|
'rd' => $flags >> 8 & 0x1, |
|
143
|
8 |
|
'ra' => $flags >> 7 & 0x1, |
|
144
|
8 |
|
'z' => $flags >> 4 & 0x7, |
|
145
|
8 |
|
'rcode' => $flags & 0xf, |
|
146
|
|
|
]; |
|
147
|
|
|
} |
|
148
|
|
|
} |
|
149
|
|
|
|
samuelwilliams /
PHP-DNS-SERVER
