Added DNS server

app/Classes/Protocol/DNS.php

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

app/Classes/Sock/SocketServer.php

@@ -12,12 +12,15 @@ final class SocketServer {
 	private int $port;					// The Port to bind to
 	private int $backlog = 5;			// Number of incoming connections queued
 
+	private int $type;					// Socket type
+
 	private array $handler;				// The class and method that will handle our connection
 
-	public function __construct(int $port,string $bind='0.0.0.0')
+	public function __construct(int $port,string $bind='0.0.0.0',int $type=SOCK_STREAM)
 	{
 		$this->bind = $bind;
 		$this->port = $port;
+		$this->type = $type;
 
 		$this->_init();
 	}
@@ -49,7 +52,18 @@ final class SocketServer {
 		if (! extension_loaded('pcntl'))
 			throw new SocketException(SocketException::CANT_ACCEPT,'Missing pcntl extension');
 
-		$this->server = socket_create(AF_INET|AF_INET6,SOCK_STREAM,SOL_TCP);
+		switch ($this->type) {
+			case SOCK_STREAM:
+				$this->server = socket_create(AF_INET|AF_INET6,$this->type,SOL_TCP);
+				break;
+
+			case SOCK_DGRAM:
+				$this->server = socket_create(AF_INET|AF_INET6,$this->type,SOL_UDP);
+				break;
+
+			default:
+				throw new \Exception('Unknown socket_type:'.$this->type);
+		}
 
 		if ($this->server === FALSE)
 			throw new SocketException(SocketException::CANT_CREATE_SOCKET,socket_strerror(socket_last_error()));
@@ -78,12 +92,22 @@ final class SocketServer {
 		if (! $this->handler)
 			throw new SocketException(SocketException::CANT_LISTEN,'Handler not set.');
 
+		if (in_array($this->type,[SOCK_STREAM,SOCK_SEQPACKET]))
 			if (socket_listen($this->server,$this->backlog) === FALSE)
 				throw new SocketException(SocketException::CANT_LISTEN,socket_strerror(socket_last_error($this->server)));
 
 		Log::info(sprintf('%s:- Listening on [%s:%d]',self::LOGKEY,$this->bind,$this->port));
 
-		$this->loop();
+		switch ($this->type) {
+			case SOCK_STREAM:
+				$this->loop_tcp();
+				break;
+
+			case SOCK_DGRAM:
+				$this->loop_udp();
+				break;
+		}
+
 		socket_close($this->server);
 
 		Log::info(sprintf('%s:= Closed [%s:%d]',self::LOGKEY,$this->bind,$this->port));
@@ -94,7 +118,7 @@ final class SocketServer {
 	 *
 	 * @throws SocketException
 	 */
-	private function loop()
+	private function loop_tcp()
 	{
 		while (TRUE) {
 			if (($accept = socket_accept($this->server)) === FALSE)
@@ -112,6 +136,19 @@ final class SocketServer {
 		}
 	}
 
+	private function loop_udp()
+	{
+		$buf = '';
+		$remote = [];
+		$remote['ip'] = NULL;
+		$remote['port'] = NULL;
+
+		while (TRUE) {
+			if (socket_recvfrom($this->server,$buf,512,MSG_WAITALL,$remote['ip'],$remote['port']))
+				$this->handler[0]->{$this->handler[1]}($remote,$buf,$this->server);
+		}
+	}
+
 	/**
 	 * Set our connection handler Class and Method
 	 *

app/Console/Commands/ServerStart.php

@@ -5,7 +5,7 @@ namespace App\Console\Commands;
 use Illuminate\Console\Command;
 use Illuminate\Support\Facades\Log;
 
-use App\Classes\Protocol\{Binkp,EMSI};
+use App\Classes\Protocol\{Binkp,DNS,EMSI};
 use App\Classes\Sock\SocketException;
 use App\Classes\Sock\SocketServer;
 use App\Models\Setup;
@@ -45,6 +45,7 @@ class ServerStart extends Command
 			$start->put('binkp',[
 				'address'=>Setup::BINKP_BIND,
 				'port'=>Setup::BINKP_PORT,
+				'proto'=>SOCK_STREAM,
 				'class'=>new Binkp($o),
 			]);
 
@@ -52,9 +53,18 @@ class ServerStart extends Command
 			$start->put('emsi',[
 				'address'=>Setup::EMSI_BIND,
 				'port'=>Setup::EMSI_PORT,
+				'proto'=>SOCK_STREAM,
 				'class'=>new EMSI($o),
 			]);
 
+		//if ($o->optionGet(Setup::O_DNS))
+			$start->put('dns',[
+				'address'=>Setup::DNS_BIND,
+				'port'=>Setup::DNS_PORT,
+				'proto'=>SOCK_DGRAM,
+				'class'=>new DNS(),
+			]);
+
 		$children = collect();
 
 		Log::debug(sprintf('%s: # Servers [%d]',self::LOGKEY,$start->count()));
@@ -79,7 +89,7 @@ class ServerStart extends Command
 				Log::withContext(['pid'=>getmypid()]);
 				Log::info(sprintf('%s: - Started [%s]',self::LOGKEY,$item));
 
-				$server = new SocketServer($config['port'],$config['address']);
+				$server = new SocketServer($config['port'],$config['address'],$config['proto']);
 				$server->setConnectionHandler([$config['class'],'onConnect']);
 
 				try {

app/Models/Setup.php

@@ -34,10 +34,13 @@ class Setup extends Model
 	public const BINKP_BIND				= '::';
 	public const EMSI_PORT				= 60179;
 	public const EMSI_BIND				= self::BINKP_BIND;
+	public const DNS_PORT				= 53;
+	public const DNS_BIND				= '::';
 
 	public const O_BINKP				= 1<<1; /* Listen for BINKD connections */
 	public const O_EMSI					= 1<<2; /* Listen for EMSI connections */
-	public const O_HIDEAKA				= 1<<3; /* Hide AKAs to different Zones */
+	public const O_DNS					= 1<<3; /* List for DNS */
+	public const O_HIDEAKA				= 1<<4; /* Hide AKAs to different Zones */
 
 	public const PRODUCT_NAME			= 'Clearing Houz';
 	public const PRODUCT_ID				= 0xAB8D;