File: //opt/cloudlinux/alt-php54/root/usr/share/pear/Net/DNS2/Resolver.php
<?php
/**
* DNS Library for handling lookups and updates.
*
* Copyright (c) 2020, Mike Pultz <mike@mikepultz.com>. All rights reserved.
*
* See LICENSE for more details.
*
* @category Networking
* @package Net_DNS2
* @author Mike Pultz <mike@mikepultz.com>
* @copyright 2020 Mike Pultz <mike@mikepultz.com>
* @license http://www.opensource.org/licenses/bsd-license.php BSD License
* @link https://netdns2.com/
* @since File available since Release 0.6.0
*
*/
/**
* This is the main resolver class, providing DNS query functions.
*
*/
class Net_DNS2_Resolver extends Net_DNS2
{
/**
* Constructor - creates a new Net_DNS2_Resolver object
*
* @param mixed $options either an array with options or null
*
* @access public
*
*/
public function __construct(array $options = null)
{
parent::__construct($options);
}
/**
* does a basic DNS lookup query
*
* @param string $name the DNS name to loookup
* @param string $type the name of the RR type to lookup
* @param string $class the name of the RR class to lookup
*
* @return Net_DNS2_Packet_Response object
* @throws Net_DNS2_Exception
* @access public
*
*/
public function query($name, $type = 'A', $class = 'IN')
{
//
// make sure we have some name servers set
//
$this->checkServers(Net_DNS2::RESOLV_CONF);
//
// we dont' support incremental zone tranfers; so if it's requested, a full
// zone transfer can be returned
//
if ($type == 'IXFR') {
$type = 'AXFR';
}
//
// if the name *looks* too short, then append the domain from the config
//
if ( (strpos($name, '.') === false) && ($type != 'PTR') ) {
$name .= '.' . strtolower($this->domain);
}
//
// create a new packet based on the input
//
$packet = new Net_DNS2_Packet_Request($name, $type, $class);
//
// check for an authentication method; either TSIG or SIG
//
if ( ($this->auth_signature instanceof Net_DNS2_RR_TSIG)
|| ($this->auth_signature instanceof Net_DNS2_RR_SIG)
) {
$packet->additional[] = $this->auth_signature;
$packet->header->arcount = count($packet->additional);
}
//
// check for the DNSSEC flag, and if it's true, then add an OPT
// RR to the additional section, and set the DO flag to 1.
//
if ($this->dnssec == true) {
//
// create a new OPT RR
//
$opt = new Net_DNS2_RR_OPT();
//
// set the DO flag, and the other values
//
$opt->do = 1;
$opt->class = $this->dnssec_payload_size;
//
// add the RR to the additional section.
//
$packet->additional[] = $opt;
$packet->header->arcount = count($packet->additional);
}
//
// set the DNSSEC AD or CD bits
//
if ($this->dnssec_ad_flag == true) {
$packet->header->ad = 1;
}
if ($this->dnssec_cd_flag == true) {
$packet->header->cd = 1;
}
//
// if caching is turned on, then check then hash the question, and
// do a cache lookup.
//
// don't use the cache for zone transfers
//
$packet_hash = '';
if ( ($this->use_cache == true) && ($this->cacheable($type) == true) ) {
//
// open the cache
//
$this->cache->open(
$this->cache_file, $this->cache_size, $this->cache_serializer
);
//
// build the key and check for it in the cache.
//
$packet_hash = md5(
$packet->question[0]->qname . '|' . $packet->question[0]->qtype
);
if ($this->cache->has($packet_hash)) {
return $this->cache->get($packet_hash);
}
}
//
// set the RD (recursion desired) bit to 1 / 0 depending on the config
// setting.
//
if ($this->recurse == false) {
$packet->header->rd = 0;
} else {
$packet->header->rd = 1;
}
//
// send the packet and get back the response
//
// *always* use TCP for zone transfers- does this cause any problems?
//
$response = $this->sendPacket(
$packet, ($type == 'AXFR') ? true : $this->use_tcp
);
//
// if strict mode is enabled, then make sure that the name that was
// looked up is *actually* in the response object.
//
// only do this is strict_query_mode is turned on, AND we've received
// some answers; no point doing any else if there were no answers.
//
if ( ($this->strict_query_mode == true)
&& ($response->header->ancount > 0)
) {
$found = false;
//
// look for the requested name/type/class
//
foreach ($response->answer as $index => $object) {
if ( (strcasecmp(trim($object->name, '.'), trim($packet->question[0]->qname, '.')) == 0)
&& ($object->type == $packet->question[0]->qtype)
&& ($object->class == $packet->question[0]->qclass)
) {
$found = true;
break;
}
}
//
// if it's not found, then unset the answer section; it's not correct to
// throw an exception here; if the hostname didn't exist, then
// sendPacket() would have already thrown an NXDOMAIN error- so the host
// *exists*, but just not the request type/class.
//
// the correct response in this case, is an empty answer section; the
// authority section may still have usual information, like a SOA record.
//
if ($found == false) {
$response->answer = [];
$response->header->ancount = 0;
}
}
//
// cache the response object
//
if ( ($this->use_cache == true) && ($this->cacheable($type) == true) ) {
$this->cache->put($packet_hash, $response);
}
return $response;
}
/**
* does an inverse query for the given RR; most DNS servers do not implement
* inverse queries, but they should be able to return "not implemented"
*
* @param Net_DNS2_RR $rr the RR object to lookup
*
* @return Net_DNS2_RR object
* @throws Net_DNS2_Exception
* @access public
*
*/
public function iquery(Net_DNS2_RR $rr)
{
//
// make sure we have some name servers set
//
$this->checkServers(Net_DNS2::RESOLV_CONF);
//
// create an empty packet
//
$packet = new Net_DNS2_Packet_Request($rr->name, 'A', 'IN');
//
// unset the question
//
$packet->question = [];
$packet->header->qdcount = 0;
//
// set the opcode to IQUERY
//
$packet->header->opcode = Net_DNS2_Lookups::OPCODE_IQUERY;
//
// add the given RR as the answer
//
$packet->answer[] = $rr;
$packet->header->ancount = 1;
//
// check for an authentication method; either TSIG or SIG
//
if ( ($this->auth_signature instanceof Net_DNS2_RR_TSIG)
|| ($this->auth_signature instanceof Net_DNS2_RR_SIG)
) {
$packet->additional[] = $this->auth_signature;
$packet->header->arcount = count($packet->additional);
}
//
// send the packet and get back the response
//
return $this->sendPacket($packet, $this->use_tcp);
}
}