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<?php
/*
* License Information:
*
* Net_DNS: A resolver library for PHP
* Copyright (c) 2002-2003 Eric Kilfoil eric@ypass.net
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* Net_DNS_Resolver object definition {{{ */
/**
* A DNS Resolver library
*
* Resolver library. Builds a DNS query packet, sends the packet to the
* server and parses the reponse.
*
* @package Net_DNS
*/
class Net_DNS_Resolver
{
/* class variable definitions {{{ */
/**
* An array of all nameservers to query
*
* @var array $nameservers
* @access public
*/
var $nameservers;
/**
* The UDP port to use for the query (default = 53)
*
* @var integer $port
* @access public
*/
var $port;
/**
* The domain in which the resolver client host resides.
*
* @var string $domain
* @access public
*/
var $domain;
/**
* The searchlist to apply to unqualified hosts
*
* An array of strings containg domains to apply to unqualified hosts
* passed to the resolver.
*
* @var array $searchlist
* @access public
*/
var $searchlist;
/**
* The number of seconds between retransmission of unaswered queries
*
* @var integer $retrans
* @access public
*/
var $retrans;
/**
* The number of times unanswered requests should be retried
*
* @var integer $retry
* @access public
*/
var $retry;
/**
* Whether or not to use TCP (Virtual Circuits) instead of UDP
*
* If set to 0, UDP will be used unless TCP is required. TCP is
* required for questions or responses greater than 512 bytes.
*
* @var boolean $usevc
* @access public
*/
var $usevc;
/**
* Unknown
*/
var $stayopen;
/**
* Ignore TC (truncated) bit
*
* If the server responds with the TC bit set on a response, and $igntc
* is set to 0, the resolver will automatically retransmit the request
* using virtual circuits (TCP).
*
* @access public
* @var boolean $igntc
*/
var $igntc;
/**
* Recursion Desired
*
* Sets the value of the RD (recursion desired) bit in the header. If
* the RD bit is set to 0, the server will not perform recursion on the
* request.
*
* @var boolean $recurse
* @access public
*/
var $recurse;
/**
* Unknown
*/
var $defnames;
/**
* Unknown
*/
var $dnsrch;
/**
* Contains the value of the last error returned by the resolver.
*
* @var string $errorstring
* @access public
*/
var $errorstring;
/**
* The origin of the packet.
*
* This contains a string containing the IP address of the name server
* from which the answer was given.
*
* @var string $answerfrom
* @access public
*/
var $answerfrom;
/**
* The size of the answer packet.
*
* This contains a integer containing the size of the DNS packet the
* server responded with.
*
* @var string $answersize
* @access public
*/
var $answersize;
/**
* The number of seconds after which a TCP connection should timeout
*
* @var integer $tcp_timeout
* @access public
*/
var $tcp_timeout;
/**
* The location of the system resolv.conf file.
*
* @var string $resolv_conf
*/
var $resolv_conf = '/etc/resolv.conf';
/**
* The name of the user defined resolv.conf
*
* The resolver will attempt to look in both the current directory as
* well as the user's home directory for a user defined resolver
* configuration file
*
* @var string $dotfile
* @see Net_DNS_Resolver::$confpath
*/
var $dotfile = '.resolv.conf';
/**
* A array of directories to search for the user's resolver config
*
* @var string $confpath
* @see Net_DNS_Resolver::$dotfile
*/
var $confpath;
/**
* debugging flag
*
* If set to true (non-zero), debugging code will be displayed as the
* resolver makes the request.
*
* @var boolean $debug;
* @access public
*/
var $debug;
/**
* use the (currently) experimental PHP socket library
*
* If set to true (non-zero), the Resolver will attempt to use the
* much more effecient PHP sockets extension (if available).
*
* @var boolean $useEnhancedSockets;
* @access public
*/
var $useEnhancedSockets = true;
/**
* An array of sockets connected to a name servers
*
* @var array $sockets
* @access private
*/
var $sockets;
/**
* axfr tcp socket
*
* Used to store a PHP socket resource for a connection to a server
*
* @var resource $_axfr_sock;
* @access private
*/
var $_axfr_sock;
/**
* axfr resource record list
*
* Used to store a resource record list from a zone transfer
*
* @var resource $_axfr_rr;
* @access private
*/
var $_axfr_rr;
/**
* axfr soa count
*
* Used to store the number of soa records received from a zone transfer
*
* @var resource $_axfr_soa_count;
* @access private
*/
var $_axfr_soa_count;
/* }}} */
/* class constructor - Net_DNS_Resolver() {{{ */
/**
* Initializes the Resolver Object
*
* @return Net_DNS_Resolver
*/
function Net_DNS_Resolver($defaults = array())
{
$mydefaults = array(
'nameservers' => array(),
'port' => '53',
'domain' => '',
'searchlist' => array(),
'retrans' => 5,
'retry' => 4,
'usevc' => 0,
'stayopen' => 0,
'igntc' => 0,
'recurse' => 1,
'defnames' => 1,
'dnsrch' => 1,
'debug' => 0,
'errorstring' => 'unknown error or no error',
'answerfrom' => '',
'answersize' => 0,
'tcp_timeout' => 120
);
foreach ($mydefaults as $k => $v) {
$this->{$k} = isset($defaults[$k]) ? $defaults[$k] : $v;
}
$this->confpath[0] = getenv('HOME');
$this->confpath[1] = '.';
$this->res_init();
}
/* }}} */
/* Net_DNS_Resolver::res_init() {{{ */
/**
* Initalizes the resolver library
*
* res_init() searches for resolver library configuration files and
* initializes the various properties of the resolver object.
*
* @see Net_DNS_Resolver::$resolv_conf, Net_DNS_Resolver::$dotfile,
* Net_DNS_Resolver::$confpath, Net_DNS_Resolver::$searchlist,
* Net_DNS_Resolver::$domain, Net_DNS_Resolver::$nameservers
* @access public
*/
function res_init()
{
$err = error_reporting(0);
if (file_exists($this->resolv_conf) && is_readable($this->resolv_conf)) {
$this->read_config($this->resolv_conf);
}
foreach ($this->confpath as $dir) {
$file = $dir.DIRECTORY_SEPARATOR.$this->dotfile;
if (file_exists($file) && is_readable($file)) {
$this->read_config($file);
}
}
$this->read_env();
if (!strlen($this->domain) && sizeof($this->searchlist)) {
$this->domain = $this->searchlist[0];
} else if (! sizeof($this->searchlist) && strlen($this->domain)) {
$this->searchlist = array($this->domain);
}
error_reporting($err);
}
/* }}} */
/* Net_DNS_Resolver::read_config {{{ */
/**
* Reads and parses a resolver configuration file
*
* @param string $file The name of the file to open and parse
*/
function read_config($file)
{
if (is_readable($file)) {
if (! ($f = fopen($file, 'r'))) {
$this->error = "can't open $file";
}
}
if (!is_resource($f)) {
$this->error = "can't open $file";
} else {
while (! feof($f)) {
$line = chop(fgets($f, 10240));
$line = ereg_replace('(.*)[;#].*', '\\1', $line);
if (ereg("^[ \t]*$", $line, $regs)) {
continue;
}
ereg("^[ \t]*([^ \t]+)[ \t]+([^ \t]+)", $line, $regs);
$option = $regs[1];
$value = $regs[2];
switch ($option) {
case 'domain':
$this->domain = $regs[2];
break;
case 'search':
$this->searchlist[count($this->searchlist)] = $regs[2];
break;
case 'nameserver':
foreach (split(' ', $regs[2]) as $ns) {
$this->nameservers[count($this->nameservers)] = $ns;
}
break;
}
}
fclose($f);
}
}
/* }}} */
/* Net_DNS_Resolver::read_env() {{{ */
/**
* Examines the environment for resolver config information
*/
function read_env()
{
if (getenv('RES_NAMESERVERS')) {
$this->nameservers = split(' ', getenv('RES_NAMESERVERS'));
}
if (getenv('RES_SEARCHLIST')) {
$this->searchlist = split(' ', getenv('RES_SEARCHLIST'));
}
if (getenv('LOCALDOMAIN')) {
$this->domain = getenv('LOCALDOMAIN');
}
if (getenv('RES_OPTIONS')) {
$env = split(' ', getenv('RES_OPTIONS'));
foreach ($env as $opt) {
list($name, $val) = split(':', $opt);
if ($val == '') {
$val = 1;
}
$this->{$name} = $val;
}
}
}
/* }}} */
/* Net_DNS_Resolver::string() {{{ */
/**
* Builds a string containing the current state of the resolver
*
* Builds formatted string containing the state of the resolver library suited
* for display.
*
* @access public
*/
function string()
{
$state = ";; Net_DNS_Resolver state:\n";
$state .= ';; domain = ' . $this->domain . "\n";
$state .= ';; searchlist = ' . implode(' ', $this->searchlist) . "\n";
$state .= ';; nameservers = ' . implode(' ', $this->nameservers) . "\n";
$state .= ';; port = ' . $this->port . "\n";
$state .= ';; tcp_timeout = ';
$state .= ($this->tcp_timeout ? $this->tcp_timeout : 'indefinite') . "\n";
$state .= ';; retrans = ' . $this->retrans . ' ';
$state .= 'retry = ' . $this->retry . "\n";
$state .= ';; usevc = ' . $this->usevc . ' ';
$state .= 'stayopen = ' . $this->stayopen . ' ';
$state .= 'igntc = ' . $this->igntc . "\n";
$state .= ';; defnames = ' . $this->defnames . ' ';
$state .= 'dnsrch = ' . $this->dnsrch . "\n";
$state .= ';; recurse = ' . $this->recurse . ' ';
$state .= 'debug = ' . $this->debug . "\n";
return $state;
}
/* }}} */
/* Net_DNS_Resolver::nextid() {{{ */
/**
* Returns the next request Id to be used for the DNS packet header
*/
function nextid()
{
if ($GLOBALS['_Net_DNS_packet_id']++ > 65535) {
$GLOBALS['_Net_DNS_packet_id']= 1;
}
return $GLOBALS['_Net_DNS_packet_id'];
}
/* }}} */
/* Net_DNS_Resolver::nameservers() {{{ */
/**
* Gets or sets the nameservers to be queried.
*
* Returns the current nameservers if an array of new nameservers is not
* given as the argument OR sets the nameservers to the given nameservers.
*
* Nameservers not specified by ip address must be able to be resolved by
* the default settings of a new Net_DNS_Resolver.
*
* @access public
*/
function nameservers($nsa = array())
{
$defres = new Net_DNS_Resolver();
if (is_array($nsa)) {
$a = array();
foreach ($nsa as $ns) {
if (preg_match('/^(\d+(:?\.\d+){0,3})$/', $ns)) {
$a[] = ($ns == 0) ? '0.0.0.0' : $ns;
} else {
$names = array();
if (!preg_match('/\./', $ns)) {
if (!empty($defres->searchlist)) {
foreach ($defres->searchlist as $suffix) {
$names[] = $ns .'.' . $suffix;
}
} elseif (!empty($defres->domain)) {
$names[] = $ns .'.'. $defres->domain;
}
} else {
$names[] = $ns;
}
$packet = $defres->search($ns);
if (is_object($packet)) {
$addresses = $this->cname_addr($names, $packet);
foreach ($addresses as $b) {
$a[] = $b;
}
$a = array_unique($a);
}
}
}
if (count($a)) {
$this->nameservers = $a;
}
}
return $this->nameservers;
}
/* }}} */
/* not tested -- Net_DNS_Resolver::cname_addr() {{{ */
function cname_addr($names, $packet)
{
$addr = array();
//my $oct2 = '(?:2[0-4]\d|25[0-5]|[0-1]?\d\d|\d)';
foreach ($packet->answer as $rr) {
if (in_array($rr->name, $names)) {
if ($rr->type == 'CNAME') {
$names[] = $rr->cname;
} elseif ($rr->type == 'A') {
// Run a basic taint check.
//next RR unless $rr->address =~ m/^($oct2\.$oct2\.$oct2\.$oct2)$/o;
$addr[] = $rr->address;
}
}
}
return $addr;
}
/* }}} */
/* Net_DNS_Resolver::search() {{{ */
/**
* Searches nameservers for an answer
*
* Goes through the search list and attempts to resolve name based on
* the information in the search list.
*
* @param string $name The name (LHS) of a resource record to query.
* @param string $type The type of record to query.
* @param string $class The class of record to query.
* @return mixed an object of type Net_DNS_Packet on success,
* or false on failure.
* @see Net_DNS::typesbyname(), Net_DNS::classesbyname()
* @access public
*/
function search($name, $type = 'A', $class = 'IN')
{
/*
* If the name looks like an IP address then do an appropriate
* PTR query.
*/
if (preg_match('/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/', $name, $regs)) {
$name = $regs[4].'.'.$regs[3].'.'.$regs[2].'.'.$regs[1].'.in-addr.arpa.';
$type = 'PTR';
}
/*
* If the name contains at least one dot then try it as is first.
*/
if (strstr($name, '.')) {
if ($this->debug) {
echo ";; search($name, $type, $class)\n";
}
$ans = $this->query($name, $type, $class);
if (is_object($ans) && ($ans->header->ancount > 0)) {
return $ans;
}
}
/*
* If the name does not end in a dot then apply the search list.
*/
$domain = '';
if ((! preg_match('/\.$/', $name)) && $this->dnsrch) {
foreach ($this->searchlist as $domain) {
$newname = "$name.$domain";
if ($this->debug) {
echo ";; search($newname, $type, $class)\n";
}
$ans = $this->query($newname, $type, $class);
if (is_object($ans) && ($ans->header->ancount > 0)) {
return $ans;
}
}
}
/*
* Finally, if the name has no dots then try it as is.
*/
if (strpos($name, '.') === false) {
if ($this->debug) {
echo ";; search($name, $type, $class)\n";
}
$ans = $this->query($name.'.', $type, $class);
if (is_object($ans) && ($ans->header->ancount > 0)) {
return $ans;
}
}
/*
* No answer was found.
*/
return false;
}
/* }}} */
/* Net_DNS_Resolver::rawQuery() {{{ */
/**
* Queries nameservers for an answer
*
* Queries the nameservers listed in the resolver configuration for an
* answer to a question packet.
*
* @param string $name The name (LHS) of a resource record to query.
* @param string $type The type of record to query.
* @param string $class The class of record to query.
* @return mixed an object of type Net_DNS_Packet, regardless of whether the packet
* has an answer or not
* @see Net_DNS::typesbyname(), Net_DNS::classesbyname()
* @access public
*/
function rawQuery($name, $type = 'A', $class = 'IN')
{
/*
* If the name does not contain any dots then append the default domain.
*/
if ((strchr($name, '.') < 0) && $this->defnames) {
$name .= '.' . $this->domain;
}
/*
* If the name looks like an IP address then do an appropriate
* PTR query.
*/
if (preg_match('/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/', $name, $regs)) {
$name = $regs[4].'.'.$regs[3].'.'.$regs[2].'.'.$regs[1].'.in-addr.arpa.';
$type = 'PTR';
}
if ($this->debug) {
echo ";; query($name, $type, $class)\n";
}
$packet = new Net_DNS_Packet($this->debug);
$packet->buildQuestion($name, $type, $class);
$packet->header->rd = $this->recurse;
$ans = $this->send($packet);
return $ans;
}
/* }}} */
/* Net_DNS_Resolver::query() {{{ */
/**
* Queries nameservers for an answer
*
* Queries the nameservers listed in the resolver configuration for an
* answer to a question packet.
*
* @param string $name The name (LHS) of a resource record to query.
* @param string $type The type of record to query.
* @param string $class The class of record to query.
* @return mixed an object of type Net_DNS_Packet on success,
* or false on failure.
* @see Net_DNS::typesbyname(), Net_DNS::classesbyname()
* @access public
*/
function query($name, $type = 'A', $class = 'IN')
{
$ans = $this->rawQuery($name, $type, $class);
if (is_object($ans) && $ans->header->ancount > 0) {
return $ans;
}
return false;
}
/* }}} */
/* Net_DNS_Resolver::send($packetORname, $qtype = '', $qclass = '') {{{ */
/**
* Sends a packet to a nameserver
*
* Determines the appropriate communication method (UDP or TCP) and
* sends a DNS packet to a nameserver. Use of the this function
* directly is discouraged. $packetORname should always be a properly
* formatted binary DNS packet. However, it is possible to send a
* query here and bypass Net_DNS_Resolver::query()
*
* @param string $packetORname A binary DNS packet stream or a
* hostname to query
* @param string $qtype This should not be used
* @param string $qclass This should not be used
* @return object Net_DNS_Packet An answer packet object
*/
function send($packetORname, $qtype = '', $qclass = '')
{
$packet = $this->make_query_packet($packetORname, $qtype, $qclass);
$packet_data = $packet->data();
if ($this->usevc != 0 || strlen($packet_data > 512)) {
$ans = $this->send_tcp($packet, $packet_data);
} else {
$ans = $this->send_udp($packet, $packet_data);
if ($ans && $ans->header->tc && $this->igntc != 0) {
if ($this->debug) {
echo ";;\n;; packet truncated: retrying using TCP\n";
}
$ans = $this->send_tcp($packet, $packet_data);
}
}
return $ans;
}
/* }}} */
/* Net_DNS_Resolver::printhex($packet_data) {{{ */
/**
* Prints packet data as hex code.
*/
function printhex($data)
{
$data = ' ' . $data;
$start = 0;
while ($start < strlen($data)) {
printf(';; %03d: ', $start);
for ($ctr = $start; $ctr < $start+16; $ctr++) {
if ($ctr < strlen($data)) {
printf('%02x ', ord($data[$ctr]));
} else {
echo ' ';
}
}
echo ' ';
for ($ctr = $start; $ctr < $start+16; $ctr++) {
if (ord($data[$ctr]) < 32 || ord($data[$ctr]) > 127) {
echo '.';
} else {
echo $data[$ctr];
}
}
echo "\n";
$start += 16;
}
}
/* }}} */
/* Net_DNS_Resolver::send_tcp($packet, $packet_data) {{{ */
/**
* Sends a packet via TCP to the list of name servers.
*
* @param string $packet A packet object to send to the NS list
* @param string $packet_data The data in the packet as returned by
* the Net_DNS_Packet::data() method
* @return object Net_DNS_Packet Returns an answer packet object
* @see Net_DNS_Resolver::send_udp(), Net_DNS_Resolver::send()
*/
function send_tcp($packet, $packet_data)
{
if (! count($this->nameservers)) {
$this->errorstring = 'no nameservers';
if ($this->debug) {
echo ";; ERROR: send_tcp: no nameservers\n";
}
return null;
}
$timeout = $this->tcp_timeout;
foreach ($this->nameservers as $ns) {
$dstport = $this->port;
if ($this->debug) {
echo ";; send_tcp($ns:$dstport)\n";
}
$sock_key = "$ns:$dstport";
if (isset($this->sockets[$sock_key]) && is_resource($this->sockets[$sock_key])) {
$sock = &$this->sockets[$sock_key];
} else {
if (! ($sock = @fsockopen($ns, $dstport, $errno,
$errstr, $timeout))) {
$this->errorstring = 'connection failed';
if ($this->debug) {
echo ";; ERROR: send_tcp: connection failed: $errstr\n";
}
continue;
}
$this->sockets[$sock_key] = $sock;
unset($sock);
$sock = &$this->sockets[$sock_key];
}
$lenmsg = pack('n', strlen($packet_data));
if ($this->debug) {
echo ';; sending ' . strlen($packet_data) . " bytes\n";
}
if (($sent = fwrite($sock, $lenmsg)) == -1) {
$this->errorstring = 'length send failed';
if ($this->debug) {
echo ";; ERROR: send_tcp: length send failed\n";
}
continue;
}
if (($sent = fwrite($sock, $packet_data)) == -1) {
$this->errorstring = 'packet send failed';
if ($this->debug) {
echo ";; ERROR: send_tcp: packet data send failed\n";
}
}
socket_set_timeout($sock, $timeout);
$buf = fread($sock, 2);
$e = socket_get_status($sock);
/* If $buf is empty, we want to supress errors
long enough to reach the continue; down the line */
$len = @unpack('nint', $buf);
$len = @$len['int'];
if (!$len) {
continue;
}
$buf = fread($sock, $len);
$actual = strlen($buf);
$this->answerfrom = $ns;
$this->answersize = $len;
if ($this->debug) {
echo ";; received $actual bytes\n";
}
if ($actual != $len) {
$this->errorstring = "expected $len bytes, received $buf";
if ($this->debug) {
echo ';; send_tcp: ' . $this->errorstring;
}
continue;
}
$ans = new Net_DNS_Packet($this->debug);
if (is_null($ans->parse($buf))) {
continue;
}
$this->errorstring = $ans->header->rcode;
$ans->answerfrom = $this->answerfrom;
$ans->answersize = $this->answersize;
return $ans;
}
}
/* }}} */
/* Net_DNS_Resolver::send_udp_no_sock_lib($packet, $packet_data) {{{ */
/**
* Sends a packet via UDP to the list of name servers.
*
* This function sends a packet to a nameserver. It is called by
* send_udp if the sockets PHP extension is not compiled into PHP.
*
* @param string $packet A packet object to send to the NS list
* @param string $packet_data The data in the packet as returned by
* the Net_DNS_Packet::data() method
* @return object Net_DNS_Packet Returns an answer packet object
* @see Net_DNS_Resolver::send_tcp(), Net_DNS_Resolver::send(),
* Net_DNS_Resolver::send_udp(), Net_DNS_Resolver::send_udp_with_sock_lib()
*/
function send_udp_no_sock_lib($packet, $packet_data)
{
$retrans = $this->retrans;
$timeout = $retrans;
/*
* PHP doesn't have excellent socket support as of this writing.
* This needs to be rewritten when PHP POSIX socket support is
* complete.
* Obviously, this code is MUCH different than the PERL implementation
*/
$w = error_reporting(0);
$ctr = 0;
// Create a socket handle for each nameserver
foreach ($this->nameservers as $nameserver) {
if ($sock[$ctr++] = fsockopen("udp://$nameserver", $this->port)) {
$peerhost[$ctr-1] = $nameserver;
$peerport[$ctr-1] = $this->port;
socket_set_blocking($sock[$ctr-1], false);
} else {
$ctr--;
}
}
error_reporting($w);
if ($ctr == 0) {
$this->errorstring = 'no nameservers';
return null;
}
for ($i = 0; $i < $this->retry; $i++, $retrans *= 2,
$timeout = (int) ($retrans / $ctr)) {
if ($timeout < 1) {
$timeout = 1;
}
foreach ($sock as $k => $s) {
if ($this->debug) {
echo ';; send_udp(' . $peerhost[$k] . ':' . $peerport[$k] . '): sending ' . strlen($packet_data) . " bytes\n";
}
if (! fwrite($s, $packet_data)) {
if ($this->debug) {
echo ";; send error\n";
}
}
/*
* Here's where it get's really nasty. We don't have a select()
* function here, so we have to poll for a response... UGH!
*/
$timetoTO = time() + (double)microtime() + $timeout;
/*
* let's sleep for a few hundred microseconds to let the
* data come in from the network...
*/
usleep(500);
$buf = '';
while (! strlen($buf) && $timetoTO > (time() +
(double)microtime())) {
socket_set_blocking($s, false);
if ($buf = fread($s, 512)) {
$this->answerfrom = $peerhost[$k];
$this->answersize = strlen($buf);
if ($this->debug) {
echo ';; answer from ' . $peerhost[$k] . ':' .
$peerport[$k] . ': ' . strlen($buf) . " bytes\n";
}
$ans = new Net_DNS_Packet($this->debug);
if ($ans->parse($buf)) {
if ($ans->header->qr != '1') {
continue;
}
if ($ans->header->id != $packet->header->id) {
continue;
}
$this->errorstring = $ans->header->rcode;
$ans->answerfrom = $this->answerfrom;
$ans->answersize = $this->answersize;
return $ans;
}
}
// Sleep another 1/100th of a second... this sucks...
usleep(1000);
}
}
$this->errorstring = 'query timed out';
return null;
}
}
/* }}} */
/* Net_DNS_Resolver::send_udp_with_sock_lib($packet, $packet_data) {{{ */
/**
* Sends a packet via UDP to the list of name servers.
*
* This function sends a packet to a nameserver. It is called by
* send_udp if the sockets PHP extension is compiled into PHP.
*
* @param string $packet A packet object to send to the NS list
* @param string $packet_data The data in the packet as returned by
* the Net_DNS_Packet::data() method
* @return object Net_DNS_Packet Returns an answer packet object
* @see Net_DNS_Resolver::send_tcp(), Net_DNS_Resolver::send(),
* Net_DNS_Resolver::send_udp(), Net_DNS_Resolver::send_udp_no_sock_lib()
*/
function send_udp_with_sock_lib($packet, $packet_data)
{
$retrans = $this->retrans;
$timeout = $retrans;
//$w = error_reporting(0);
$ctr = 0;
// Create a socket handle for each nameserver
foreach ($this->nameservers as $nameserver) {
if ((($sock[$ctr++] = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP))) &&
socket_connect($sock[$ctr-1], $nameserver, $this->port))
{
$peerhost[$ctr-1] = $nameserver;
$peerport[$ctr-1] = $this->port;
socket_set_nonblock($sock[$ctr-1]);
} else {
$ctr--;
}
}
//error_reporting($w);
if ($ctr == 0) {
$this->errorstring = 'no nameservers';
return null;
}
// Try each nameserver up to $this->retry times
for ($i = 0; $i < $this->retry; $i++) {
if ($i != 0) {
// Set the timeout for each retry based on the number of
// nameservers there is a connected socket for.
$retrans *= 2;
$timeout = (int) ($retrans / $ctr);
}
// Make sure the timeout is at least 1 second
if ($timeout < 1) {
$timeout = 1;
}
// Try each nameserver
foreach ($sock as $k => $s) {
if ($this->debug) {
echo "\n;; send_udp(" . $peerhost[$k] . ':' . $peerport[$k] . '): sending ' . strlen($packet_data) . " bytes\n";
}
if (! socket_write($s, $packet_data)) {
if ($this->debug) {
echo ";; send error\n";
}
}
$set = array($s);
if ($this->debug) {
echo ";; timeout set to $timeout seconds\n";
}
$changed = socket_select($set, $w = null, $e = null, $timeout);
if ($changed) {
// Test to see if the connection was refused. Linux servers will send
// an ICMP message which will cause the client's next system call to
// return ECONNREFUSED if the server is not listening on the ip:port queried
if (socket_get_option($s, SOL_SOCKET, SO_ERROR) == SOCKET_ECONNREFUSED) {
// Unix socket connection was refused
if ($this->debug) {
echo ';; connection to ' . $peerhost[$k] . ':' . $peerport[$k] . " was refused\n";
}
// Try the next server.
continue;
}
// Read the response
$buf = @socket_read($s, 512);
if ($buf === false) {
// No data could be read from socket
if ($this->debug) {
echo ';; no data could be read from ' . $peerhost[$k] . ':' . $peerport[$k] . "\n";
echo ';; socket_error: ' . socket_strerror(socket_last_error()) . "\n";
}
// Reset the non-specific socket error status
socket_clear_error();
// Try the next server.
continue;
}
$this->answerfrom = $peerhost[$k];
$this->answersize = strlen($buf);
if ($this->debug) {
echo ';; answer from ' . $peerhost[$k] . ':' .
$peerport[$k] . ': ' . strlen($buf) . " bytes\n";
}
$ans = new Net_DNS_Packet($this->debug);
if ($ans->parse($buf)) {
if ($ans->header->qr != '1') {
// Ignore packet if it is not a response
continue;
} elseif ($ans->header->id != $packet->header->id) {
// Ignore packet if the response id does not match the query id
continue;
} else {
// Return the DNS response packet
$this->errorstring = $ans->header->rcode;
$ans->answerfrom = $this->answerfrom;
$ans->answersize = $this->answersize;
return $ans;
}
}
} elseif ($this->debug) {
echo ";; query to ". $peerhost[$k] . ':' . $peerport[$k] . " timed out\n";
}
}
}
$this->errorstring = 'query timed out';
return null;
}
/* }}} */
/* Net_DNS_Resolver::send_udp($packet, $packet_data) {{{ */
/**
* Sends a packet via UDP to the list of name servers.
*
* This function sends a packet to a nameserver. send_udp calls
* either Net_DNS_Resolver::send_udp_no_sock_lib() or
* Net_DNS_Resolver::send_udp_with_sock_lib() depending on whether or
* not the sockets extension is compiled into PHP. Note that using the
* sockets extension is MUCH more efficient.
*
* @param object Net_DNS_Packet $packet A packet object to send to the NS list
* @param string $packet_data The data in the packet as returned by
* the Net_DNS_Packet::data() method
* @return object Net_DNS_Packet Returns an answer packet object
* @see Net_DNS_Resolver::send_tcp(), Net_DNS_Resolver::send(),
* Net_DNS_Resolver::send_udp(), Net_DNS_Resolver::send_udp_no_sock_lib()
*/
function send_udp($packet, $packet_data)
{
if (extension_loaded('sockets') && $this->useEnhancedSockets) {
if ($this->debug) {
echo "\n;; using extended PHP sockets\n";
}
return $this->send_udp_with_sock_lib($packet, $packet_data);
} else {
if ($this->debug) {
echo "\n;; using simple sockets\n";
}
return $this->send_udp_no_sock_lib($packet, $packet_data);
}
}
/* }}} */
/* Net_DNS_Resolver::make_query_packet($packetORname, $type = '', $class = '') {{{ */
/**
* Unknown
*/
function make_query_packet($packetORname, $type = '', $class = '')
{
if (is_object($packetORname) && strcasecmp(get_class($packetORname), 'net_dns_packet') == 0) {
$packet = $packetORname;
} else {
$name = $packetORname;
if ($type == '') {
$type = 'A';
}
if ($class == '') {
$class = 'IN';
}
/*
* If the name looks like an IP address then do an appropriate
* PTR query.
*/
if (preg_match('/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/', $name, $regs)) {
$name = $regs[4].'.'.$regs[3].'.'.$regs[2].'.'.$regs[1].'.in-addr.arpa.';
$type = 'PTR';
}
if ($this->debug) {
echo ";; query($name, $type, $class)\n";
}
$packet = new Net_DNS_Packet($this->debug);
$packet->buildQuestion($name, $type, $class);
}
$packet->header->rd = $this->recurse;
return $packet;
}
/* }}} */
/* Net_DNS_Resolver::axfr_old($dname, $class = 'IN') {{{ */
/**
* Performs an AXFR query (zone transfer) (OLD BUGGY STYLE)
*
* This is deprecated and should not be used!
*
* @param string $dname The domain (zone) to transfer
* @param string $class The class in which to look for the zone.
* @return object Net_DNS_Packet
* @access public
*/
function axfr_old($dname, $class = 'IN')
{
return $this->axfr($dname, $class, true);
}
/* }}} */
/* Net_DNS_Resolver::axfr($dname, $class = 'IN', $old = false) {{{ */
/**
* Performs an AXFR query (zone transfer)
*
* Requests a zone transfer from the nameservers. Note that zone
* transfers will ALWAYS use TCP regardless of the setting of the
* Net_DNS_Resolver::$usevc flag. If $old is set to true, Net_DNS requires
* a nameserver that supports the many-answers style transfer format. Large
* zone transfers will not function properly. Setting $old to true is _NOT_
* recommended and should only be used for backwards compatibility.
*
* @param string $dname The domain (zone) to transfer
* @param string $class The class in which to look for the zone.
* @param boolean $old Requires 'old' style many-answer format to function.
Used for backwards compatibility only.
* @return object Net_DNS_Packet
* @access public
*/
function axfr($dname, $class = 'IN', $old = false)
{
if ($old) {
if ($this->debug) {
echo ";; axfr_start($dname, $class)\n";
}
if (! count($this->nameservers)) {
$this->errorstring = 'no nameservers';
if ($this->debug) {
echo ";; ERROR: no nameservers\n";
}
return null;
}
$packet = $this->make_query_packet($dname, 'AXFR', $class);
$packet_data = $packet->data();
$ans = $this->send_tcp($packet, $packet_data);
return $ans;
} else {
if ($this->axfr_start($dname, $class) === null) {
return null;
}
$ret = array();
while (($ans = $this->axfr_next()) !== null) {
if ($ans === null) {
return null;
}
array_push($ret, $ans);
}
return $ret;
}
}
/* }}} */
/* Net_DNS_Resolver::axfr_start($dname, $class = 'IN') {{{ */
/**
* Sends a packet via TCP to the list of name servers.
*
* @param string $packet A packet object to send to the NS list
* @param string $packet_data The data in the packet as returned by
* the Net_DNS_Packet::data() method
* @return object Net_DNS_Packet Returns an answer packet object
* @see Net_DNS_Resolver::send_tcp()
*/
function axfr_start($dname, $class = 'IN')
{
if ($this->debug) {
echo ";; axfr_start($dname, $class)\n";
}
if (! count($this->nameservers)) {
$this->errorstring = "no nameservers";
if ($this->debug) {
echo ";; ERROR: axfr_start: no nameservers\n";
}
return null;
}
$packet = $this->make_query_packet($dname, "AXFR", $class);
$packet_data = $packet->data();
$timeout = $this->tcp_timeout;
foreach ($this->nameservers as $ns) {
$dstport = $this->port;
if ($this->debug) {
echo ";; axfr_start($ns:$dstport)\n";
}
$sock_key = "$ns:$dstport";
if (is_resource($this->sockets[$sock_key])) {
$sock = &$this->sockets[$sock_key];
} else {
if (! ($sock = fsockopen($ns, $dstport, $errno,
$errstr, $timeout))) {
$this->errorstring = "connection failed";
if ($this->debug) {
echo ";; ERROR: axfr_start: connection failed: $errstr\n";
}
continue;
}
$this->sockets[$sock_key] = $sock;
unset($sock);
$sock = &$this->sockets[$sock_key];
}
$lenmsg = pack("n", strlen($packet_data));
if ($this->debug) {
echo ";; sending " . strlen($packet_data) . " bytes\n";
}
if (($sent = fwrite($sock, $lenmsg)) == -1) {
$this->errorstring = "length send failed";
if ($this->debug) {
echo ";; ERROR: axfr_start: length send failed\n";
}
continue;
}
if (($sent = fwrite($sock, $packet_data)) == -1) {
$this->errorstring = "packet send failed";
if ($this->debug) {
echo ";; ERROR: axfr_start: packet data send failed\n";
}
}
socket_set_timeout($sock, $timeout);
$this->_axfr_sock = $sock;
$this->_axfr_rr = array();
$this->_axfr_soa_count = 0;
return $sock;
}
}
/* }}} */
/* Net_DNS_Resolver::axfr_next() {{{ */
/**
* Requests the next RR from a existing transfer started with axfr_start
*
* @return object Net_DNS_RR Returns a Net_DNS_RR object of the next RR
* from a zone transfer.
* @see Net_DNS_Resolver::send_tcp()
*/
function axfr_next()
{
if (! count($this->_axfr_rr)) {
if (! isset($this->_axfr_sock) || ! is_resource($this->_axfr_sock)) {
$this->errorstring = 'no zone transfer in progress';
return null;
}
$timeout = $this->tcp_timeout;
$buf = $this->read_tcp($this->_axfr_sock, 2, $this->debug);
if (! strlen($buf)) {
$this->errorstring = 'truncated zone transfer';
return null;
}
$len = unpack('n1len', $buf);
$len = $len['len'];
if (! $len) {
$this->errorstring = 'truncated zone transfer';
return null;
}
$buf = $this->read_tcp($this->_axfr_sock, $len, $this->debug);
if ($this->debug) {
echo ';; received ' . strlen($buf) . "bytes\n";
}
if (strlen($buf) != $len) {
$this->errorstring = 'expected ' . $len . ' bytes, received ' . strlen($buf);
if ($this->debug) {
echo ';; ' . $err . "\n";
}
return null;
}
$ans = new Net_DNS_Packet($this->debug);
if (! $ans->parse($buf)) {
if (! $this->errorstring) {
$this->errorstring = 'unknown error during packet parsing';
}
return null;
}
if ($ans->header->ancount < 1) {
$this->errorstring = 'truncated zone transfer';
return null;
}
if ($ans->header->rcode != 'NOERROR') {
$this->errorstring = 'errorcode ' . $ans->header->rcode . ' returned';
return null;
}
foreach ($ans->answer as $rr) {
if ($rr->type == 'SOA') {
if (++$this->_axfr_soa_count < 2) {
array_push($this->_axfr_rr, $rr);
}
} else {
array_push($this->_axfr_rr, $rr);
}
}
if ($this->_axfr_soa_count >= 2) {
unset($this->_axfr_sock);
}
}
$rr = array_shift($this->_axfr_rr);
return $rr;
}
/* }}} */
/* Net_DNS_Resolver::read_tcp() {{{ */
/**
* Unknown - not ported yet
*/
function read_tcp($sock, $nbytes, $debug = 0)
{
$buf = '';
while (strlen($buf) < $nbytes) {
$nread = $nbytes - strlen($buf);
$read_buf = '';
if ($debug) {
echo ";; read_tcp: expecting $nread bytes\n";
}
$read_buf = fread($sock, $nread);
if (! strlen($read_buf)) {
if ($debug) {
echo ";; ERROR: read_tcp: fread failed\n";
}
break;
}
if ($debug) {
echo ';; read_tcp: received ' . strlen($read_buf) . " bytes\n";
}
if (!strlen($read_buf)) {
break;
}
$buf .= $read_buf;
}
return $buf;
}
/* }}} */
}
/* }}} */
/* VIM settings {{{
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* soft-stop-width: 4
* c indent on
* expandtab on
* End:
* vim600: sw=4 ts=4 sts=4 cindent fdm=marker et
* vim<600: sw=4 ts=4
* }}} */
?>
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