371 lines
10 KiB
PHP
371 lines
10 KiB
PHP
<?php
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namespace App\Classes\Protocol;
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use App\Models\Address;
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use App\Models\Domain;
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use Illuminate\Support\Collection;
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use Illuminate\Support\Facades\Log;
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use App\Http\Controllers\DomainController;
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final class DNS
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{
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private const LOGKEY = 'PD-';
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private string $rx_buf;
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private array $header;
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private array $remote;
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private int $rx_ptr;
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private \Socket $socket;
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// DNS Response codes
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public const DNS_NOERROR = 0; // No error
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public const DNS_FORMERR = 1; // Format Error - The dns server could not read / understand the query
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public const DNS_SERVFAIL = 2; // Server Failure - There was a dns error with the dns server
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public const DNS_NAMEERR = 3; // Name Error - This specifies that the domain name in the query does not exist, it is only valid from an authoritative server
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public const DNS_NOTIMPLEMENTED = 4;// Not implemented - The requested query is not supported by the dns server
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public const DNS_REFUSED = 5; // Refused - The dns server refuses to process the dns query
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// DNS Query Classes
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public const DNS_QUERY_IN = 1; // Internet (this is the main one that is used)
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// DNS Query Types
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public const DNS_TYPE_A = 1; // A Records
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public const DNS_TYPE_NS = 2; // NS Records
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public const DNS_TYPE_CNAME = 5; // CNAME Records
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public const DNS_TYPE_SOA = 6; // SOA Records
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public const DNS_TYPE_MX = 15; // MX Records
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public const DNS_TYPE_TXT = 16; // TXT Records
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public const DNS_TYPE_AAAA = 28; // AAAA Records
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// https://github.com/guyinatuxedo/dns-fuzzer/blob/master/dns.md
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private const header = [ // Struct of a DNS query
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'id' => [0x00,'n',1], // ID
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'header' => [0x01,'n',1], // Header
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'qdcount' => [0x02,'n',1], // Entries in the question
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'ancount' => [0x03,'n',1], // Resource Records in the answer
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'nscount' => [0x04,'n',1], // Server Resource Records in the answer
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'arcount' => [0x05,'n',1], // Resource Records in the addition records section
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];
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/**
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* Handle a DNS query
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*
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* https://www.ietf.org/rfc/rfc1035.txt
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* https://github.com/guyinatuxedo/dns-fuzzer/blob/master/dns.md
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*
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* labels 63 octets or less
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* names 255 octets or less
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* TTL positive values of a signed 32 bit number.
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* UDP messages 512 octets or less
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*
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* @param array $remote
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* @param string $buf
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* @param \Socket $socket
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* @return void
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*
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dig +noedns -t CNAME mail.dcml.au @1.1.1.1
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; <<>> DiG 9.10.6 <<>> +noedns -t CNAME mail.dcml.au @1.1.1.1
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;; global options: +cmd
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;; Got answer:
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;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6473
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;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
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;; QUESTION SECTION:
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;mail.dcml.au. IN CNAME
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;; ANSWER SECTION:
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mail.dcml.au. 300 IN CNAME l.dege.au.
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;; Query time: 43 msec
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;; SERVER: 1.1.1.1#53(1.1.1.1)
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;; WHEN: Thu Apr 20 06:47:55 PST 2023
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;; MSG SIZE rcvd: 51
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06:47:54.995929 IP 192.168.130.184.51502 > one.one.one.one.domain: 6473+ CNAME? mail.dcml.au. (30)
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0x0000: cc03 d9cc 88cb bcd0 7414 d055 0800 4500 ........t..U..E.
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0x0010: 003a eee2 0000 4011 466e c0a8 82b8 0101 .:....@.Fn......
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0x0020: 0101 c92e 0035 0026 bb5f|1949 0120 0001 .....5.&._.I....
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0x0030: 0000 0000 0000 046d 6169 6c04 6463 6d6c .......mail.dcml
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0x0040: 0261 7500 0005 0001 .au.....
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06:47:55.034171 IP one.one.one.one.domain > 192.168.130.184.51502: 6473$ 1/0/0 CNAME l.dege.au. (51)
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0x0000: bcd0 7414 d055 cc03 d9cc 88cb 0800 4588 ..t..U........E.
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0x0010: 004f 514a 4000 3a11 a969 0101 0101 c0a8 .OQJ@.:..i......
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0x0020: 82b8 0035 c92e 003b 9274|1949 81a0 0001 ...5...;.t.I....
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0x0030: 0001 0000 0000 046d 6169 6c04 6463 6d6c .......mail.dcml
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0x0040: 0261 7500 0005 0001 c00c 0005 0001 0000 .au.............
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0x0050: 012c 0009 016c 0464 6567 65c0 16 .,...l.dege..
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*/
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public function onConnect(array $remote,string $buf,\Socket $socket)
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{
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Log::debug(sprintf('%s:+ DNS Query',self::LOGKEY));
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$header_len = collect(self::header)->sum(function($item) { return $item[2]*2; });
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$this->rx_buf = $buf;
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$this->rx_ptr = 0;
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// DNS Query header
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$this->header = unpack(self::unpackheader(self::header),$buf);
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$this->rx_ptr += $header_len;
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$this->remote = $remote;
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$this->socket = $socket;
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// If there is no query count, then its an error
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if ($this->header['qdcount'] !== 1) {
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Log::error(sprintf('%s:! DNS query doesnt have the right number of queries [%d]',self::LOGKEY,$this->header['qdcount']));
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$this->reply(self::DNS_FORMERR);
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return;
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}
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// Get the query elements
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$labels = collect();
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while (($len=ord($this->read(1))) !== 0x00)
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$labels->push($this->read($len));
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$this->question = substr($this->rx_buf,$header_len,$this->rx_ptr-$header_len+4);
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// We need a minimum of f.n.z.d.root
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if ($labels->count() < 5) {
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Log::error(sprintf('%s:! DNS query for a resource we dont manage [%s]',self::LOGKEY,$labels->join('.')));
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$this->reply(self::DNS_NAMEERR);
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return;
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}
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// First check that it is a query we can answer
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// First label should be p.. or f..
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if (! is_null($p=$this->parse('p',$labels->first())))
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$labels->shift();
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if (is_null($f=$this->parse('f',$labels->shift())))
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return $this->nameerr($labels);
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if (is_null($n=$this->parse('n',$labels->shift())))
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return $this->nameerr($labels);
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if (is_null($z=$this->parse('z',$labels->shift())))
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return $this->nameerr($labels);
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if (is_null($d=$labels->shift()))
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return $this->nameerr($labels);
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// Make sure we have a root/base domain
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if (! $labels->count())
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return $this->nameerr($labels);
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$rootdn = $labels->join('.');
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$ao = Address::findFTN(sprintf('%d:%d/%d.%d@%s',$z,$n,$f,$p,$d));
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// Check we have the right record
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if ((! $ao) || (! $ao->system->mailer_address) || (($rootdn !== 'ftn') && ((! $ao->zone->domain->dnsdomain) || ($ao->zone->domain->dnsdomain !== $d.'.'.$rootdn))))
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return $this->nameerr($labels);
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// Get the query type/class
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$result = unpack('ntype/nclass',$x=$this->read(4));
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// If the wrong class
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if ($result['class'] !== self::DNS_QUERY_IN) {
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Log::error(sprintf('%s:! We only service Internet queries [%d]',self::LOGKEY,$result['class']));
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$this->reply(self::DNS_NOTIMPLEMENTED);
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return;
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}
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// Check the class
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switch ($result['type']) {
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case self::DNS_TYPE_CNAME:
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case self::DNS_TYPE_A:
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case self::DNS_TYPE_AAAA:
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Log::debug(sprintf('%s:= Returning [%s] for DNS query [%s]',self::LOGKEY,$ao->system->mailer_address,$ao->ftn));
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$this->reply(
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self::DNS_NOERROR,
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$this->question,
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[serialize(explode('.',$ao->system->mailer_address)) => self::DNS_TYPE_CNAME]);
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break;
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default:
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Log::error(sprintf('%s:! We dont support DNS query types [%d]',self::LOGKEY,$result['type']));
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$this->reply(self::DNS_NOTIMPLEMENTED);
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}
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}
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/**
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* Return a compression string for a specific offset
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*
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* @param int $offset
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* @return string
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*/
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private function compress(int $offset): string
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{
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return pack('n',$offset | (3 << 14));
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}
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private function nameerr(Collection $labels)
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{
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Log::error(sprintf('%s:! DNS query for a resource we dont manage [%s]',self::LOGKEY,$labels->join('.')));
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$this->reply(self::DNS_NAMEERR);
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}
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/**
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* Parse a label for a fido address nibble
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*
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* @param string $prefix
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* @param string $label
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* @return string|null
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*/
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private function parse(string $prefix,string $label): ?string
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{
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$m = [];
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return (preg_match('/^'.$prefix.'([0-9]+)+/',$label,$m) && ($m[1] <= DomainController::NUMBER_MAX))
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? $m[1]
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: NULL;
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}
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/**
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* Return a DNS response
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*
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* @param int $code
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* @param string $question
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* @param array $answer
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* @return bool
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*/
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private function reply(int $code,string $question='',array $answer=[]): bool
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{
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$header = (1 << 15); // 1b: Query/Response
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$header |= (0 << 11); // 4b: Opcode
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$header |= (0 << 10); // 1b: Authoritative Answer
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$header |= (0 << 9); // 1b: Truncated
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$header |= (0 << 8); // 1b: Recursion Desired (in queries)
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$header |= (0 << 7); // 1b: Recursion Available (in responses)
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$header |= (0 << 4); // 3b: Zero (future, should be zero)
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$header |= $code; // 4b: Result Code
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$q = $question ? 1 : 0;
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$r = count($answer);
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$nscount = 0;
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$arcount = 0;
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$reply = pack('nnnnnn',$this->header['id'],$header,$q,$r,$nscount,$arcount);
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// Return the answer
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if ($r) {
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// Question
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$reply .= $question;
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// @todo In the case we return a CNAME and an A record, this should reference the CNAME domain when returning the A record
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foreach ($answer as $item => $type)
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$reply .= $this->rr($this->compress(12),unserialize($item),$type,300);
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} else {
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$reply .= $question;
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}
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// nscount
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//$reply .= $this->rr($this->domain_split('net1.fsxnet.nz'),["a","root-servers","net"],self::DNS_TYPE_NS,300);
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if (! socket_sendto($this->socket,$reply,strlen($reply),0,(string)$this->remote['ip'],(int)$this->remote['port'])) {
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Log::error(sprintf('%s:! Error [%s] sending DNS reply to [%s:%d]',
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self::LOGKEY,
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socket_strerror(socket_last_error()),
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$this->remote['ip'],
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$this->remote['port']
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));
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return FALSE;
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}
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return TRUE;
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}
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private function domain_split(string $domain): string
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{
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$a = '';
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foreach (explode('.',$domain) as $item)
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$a .= pack('C',strlen($item)).$item;
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return $a;
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}
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/**
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* Read from a rx_buf
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*
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* @param int $len
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* @return string
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*/
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private function read(int $len): string
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{
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$result = substr($this->rx_buf,$this->rx_ptr,$len);
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$this->rx_ptr += $len;
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return $result;
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}
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/**
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* Return a DNS Resource Record
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*
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* @param string $query - Domain in the query
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* @param mixed $ars - Answer resources
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* @param int $type - Resource type
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* @param int $ttl - Time to live
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* @return string
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*/
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private function rr(string $query,mixed $ars,int $type,int $ttl): string
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{
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// Reference the domain query in the question
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$reply = $query;
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// Record Type
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$reply .= pack('n',$type);
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// Internet
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$reply .= pack('n',self::DNS_QUERY_IN);
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$reply .= pack('n',0);
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// TTL
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$reply .= pack('n',$ttl);
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// Answer
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$a = '';
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switch ($type) {
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case self::DNS_TYPE_CNAME:
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case self::DNS_TYPE_NS:
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foreach ($ars as $item)
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$a .= pack('C',strlen($item)).$item;
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$a .= "\x00";
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break;
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case self::DNS_TYPE_A:
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case self::DNS_TYPE_AAAA:
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$a .= $ars;
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}
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$reply .= pack('n',strlen($a)).$a;
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return $reply;
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}
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/**
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* Unpack our configured DNS header
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*
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* @param array $pack
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* @return string
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*/
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protected static function unpackheader(array $pack): string
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{
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return join('/',
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collect($pack)
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->sortBy(function($k,$v) {return $k[0];})
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->transform(function($k,$v) {return $k[1].$v;})
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->values()
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->toArray()
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);
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}
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} |