checkdnsrr

muscat_setup

Last updated: Sat, 17 Jul 2004

LXXI. Network Functions

Introduction

Requirements

No external libraries are needed to build this extension.

Installation

There is no installation needed to use these functions; they are part of the PHP core.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Tablo 1. Network Configuration Options

Name	Default	Changeable
define_syslog_variables	"0"	PHP_INI_ALL

For further details and definition of the PHP_INI_* constants see ini_set().

Here's a short explanation of the configuration directives.

define_syslog_variables boolean: Whether or not to define the various syslog variables (e.g. $LOG_PID, $LOG_CRON, etc.). Turning it off is a good idea performance-wise. At runtime, you can define these variables by calling define_syslog_variables().

Resource Types

This extension has no resource types defined.

Predefined Constants

The constants below are always available as part of the PHP core.

Tablo 2. openlog() Options

Constant	Description
LOG_CONS	if there is an error while sending data to the system logger, write directly to the system console
LOG_NDELAY	open the connection to the logger immediately
LOG_ODELAY	(default) delay opening the connection until the first message is logged
LOG_NOWAIT
LOG_PERROR	print log message also to standard error
LOG_PID	include PID with each message

Tablo 3. openlog() Facilities

Constant	Description
LOG_AUTH	security/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined)
LOG_AUTHPRIV	security/authorization messages (private)
LOG_CRON	clock daemon (cron and at)
LOG_DAEMON	other system daemons
LOG_KERN	kernel messages
LOG_LOCAL0 ... LOG_LOCAL7	reserved for local use, these are not available in Windows
LOG_LPR	line printer subsystem
LOG_MAIL	mail subsystem
LOG_NEWS	USENET news subsystem
LOG_SYSLOG	messages generated internally by syslogd
LOG_USER	generic user-level messages
LOG_UUCP	UUCP subsystem

Tablo 4. syslog() Priorities (in descending order)

Constant	Description
LOG_EMERG	system is unusable
LOG_ALERT	action must be taken immediately
LOG_CRIT	critical conditions
LOG_ERR	error conditions
LOG_WARNING	warning conditions
LOG_NOTICE	normal, but significant, condition
LOG_INFO	informational message
LOG_DEBUG	debug-level message

Tablo 5. dns_get_record() Options

Constant	Description
DNS_A	IPv4 Address Resource
DNS_MX	Mail Exchanger Resource
DNS_CNAME	Alias (Canonical Name) Resource
DNS_NS	Authoritative Name Server Resource
DNS_PTR	Pointer Resource
DNS_HINFO	Host Info Resource (See IANA's Operating System Names for the meaning of these values)
DNS_SOA	Start of Authority Resource
DNS_TXT	Text Resource
DNS_ANY	Any Resource Record. On most systems this returns all resource records, however it should not be counted upon for critical uses. Try DNS_ALL instead.
DNS_AAAA	IPv6 Address Resource
DNS_ALL	Iteratively query the name server for each available record type.

��indekiler
checkdnsrr -- Check DNS records corresponding to a given Internet host name or IP address
closelog -- Close connection to system logger
debugger_off -- Disable internal PHP debugger (PHP 3)
debugger_on -- Enable internal PHP debugger (PHP 3)
define_syslog_variables -- Initializes all syslog related constants
dns_check_record -- Synonym for checkdnsrr()
dns_get_mx -- Synonym for getmxrr()
dns_get_record -- Fetch DNS Resource Records associated with a hostname
fsockopen -- Open Internet or Unix domain socket connection
gethostbyaddr -- Get the Internet host name corresponding to a given IP address
gethostbyname -- Get the IP address corresponding to a given Internet host name
gethostbynamel -- Get a list of IP addresses corresponding to a given Internet host name
getmxrr -- Get MX records corresponding to a given Internet host name
getprotobyname -- Get protocol number associated with protocol name
getprotobynumber -- Get protocol name associated with protocol number
getservbyname -- Get port number associated with an Internet service and protocol
getservbyport -- Get Internet service which corresponds to port and protocol
ip2long -- Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address.
long2ip -- Converts an (IPv4) Internet network address into a string in Internet standard dotted format
openlog -- Open connection to system logger
pfsockopen -- Open persistent Internet or Unix domain socket connection
socket_get_status -- Alias of stream_get_meta_data()
socket_set_blocking -- Alias of stream_set_blocking()
socket_set_timeout -- Alias of stream_set_timeout()
syslog -- Generate a system log message

checkdnsrr

muscat_setup

Last updated: Sat, 17 Jul 2004

add a note User Contributed Notes
Network Functions

David GASTALDIN
21-Jun-2007 08:12


Here a IP-Range to CIDRs function that I wrote for the purpose of filling my Postfix client.cidr with ripe-ncc data to block spamming from useless countries. Strcmp functions are meant to work around the silly PHP string comparison which inevitably tries compare strings as numbers when possible. I'll make no comment about that fact ... bit I have to bite my tong hard :



function PlageVersCIDRs($ip_min, $ip_max) {

    $cidrs = array();

    $ip_min_bin = sprintf('%032b', $ip_min);

    $ip_max_bin = sprintf('%032b', $ip_max);

    $ip_cour_bin = $ip_min_bin;

    while (strcmp($ip_cour_bin, $ip_max_bin) <= 0) {

        $lng_reseau = 32;

        $ip_reseau_bin = $ip_cour_bin;

        while (($ip_cour_bin[$lng_reseau - 1] == '0') && (strcmp(substr_replace($ip_reseau_bin, '1', $lng_reseau - 1, 1), $ip_max_bin) <= 0)) {

            $ip_reseau_bin[$lng_reseau - 1] = '1';

            $lng_reseau--;

        }

        $cidrs[] = long2ip(bindec($ip_cour_bin)).'/'.$lng_reseau;

        $ip_cour_bin = sprintf('%032b', bindec($ip_reseau_bin) + 1);

    }

    return $cidrs;

}

claudiu at cnixs dot com
22-Apr-2007 02:52


A simple and very fast function to check against CIDR.



Your previous examples are too complicated and involves a lot of functions call.



Here it is (only with arithmetic operators and call only to ip2long () and split() ):

<?php

  function ipCIDRCheck ($IP, $CIDR) {

    list ($net, $mask) = split ("/", $CIDR);

    

    $ip_net = ip2long ($net);

    $ip_mask = ~((1 << (32 - $mask)) - 1);



    $ip_ip = ip2long ($IP);



    $ip_ip_net = $ip_ip & $ip_mask;



    return ($ip_ip_net == $ip_net);

  }

?>

call example: <?php echo ipCheck ("192.168.1.23", "192.168.1.0/24"); ?>

dand at ddchosting.com
08-Apr-2006 02:28


When I was working on a project I ran into this problem with redirecting. My solution is as follows:


header("Refresh: 5; url=../main/main.php?".session_id()."");





This allowed me to pass the session_id() which is used throughout site to make sure user has loged in. 


I hope this helps!

metator at netcabo dot pt
28-Jul-2005 07:34


Ups. The function has a bug, though the example still works with it. Just replace the $_POST variables by the function parameters.



<?

function isIPIn($ip, $net, $mask) {

   //doesn't check for the return value of ip2long

   $ip = ip2long($ip);

   $rede = ip2long($net);

   $mask = ip2long($mask);

  

   //AND

   $res = $ip & $mask;

  

   return ($res == $rede);

}

?>

metator at netcabo dot pt
27-Jul-2005 08:22


Regarding samuele's note:



You can get faster code if you apply directly what happens in  network devices, such as routers. If you AND (logic operation) the remote ip against the local netmask the result will be the network ip if the remote ip is from the local network. Example:



    192.168.0.16 = 11000000.10101000.00000000.00010000

& 255.255.255.0 = 11111111.11111111.11111111.00000000

--------------------------------------------------------------

   192.168.0.0 = 11000000.10101000.00000000.00000000



And now the code. My example uses a html form where you place the values you want to test:



<HTML><HEAD><TITLE>Check IP</TITLE>

</HEAD><BODY>

    <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST">



Hope you find this useful.

        IP to check: <input type="text" name="ip"> <br>

        Local network ip: <input type="text" name="net"> <br>

        Local netmask: <input type="text" name="mask"> <br>

        <input type="submit" name="check" value="Check it!">

    </form>

    <?php



/**

 * @param string $ip IP to check in dotted decimal format

 * @param string $net Network IP in dotted decimal format

 * @param string $mask Netmask in dotted decimal format

 * @returns true if the ip belongs to the network, false otherwise

 **/

function isIPIn($ip, $net, $mask) {

    //doesn't check for the return value of ip2long

    $ip = ip2long($_POST['ip']);

    $rede = ip2long($_POST['net']);

    $mask = ip2long($_POST['mask']);

    

    //AND 

    $res = $ip & $mask;

    

    return ($res == $rede);

}



if (isset($_POST['check'])) {

     echo isIPIn($_POST['ip'], $_POST['net'], $_POST['mask']) ? "IP IN.": "IP OUT.";

}

 ?>

</BODY><HTML>

nexxer at rogers dot com
24-Feb-2005 05:16


In Trevor Hemsley's translation of the perl range2cidr function, the 



while ($end > $start) 



condition should be



while ($end >= $start)



otherwise it won't work for /32s, ie if you feed range2cidr("1.2.3.4", "1.2.3.4").



-- nex

samuele at norsam dot org
25-Nov-2003 09:01


To find if an IP is in a net/mask (very fast):

<?php

function isIPIn($ip,$net,$mask) {

   $lnet=ip2long($net);

   $lip=ip2long($ip);

   $binnet=str_pad( decbin($lnet),32,"0","STR_PAD_LEFT" );

   $firstpart=substr($binnet,0,$mask);

   $binip=str_pad( decbin($lip),32,"0","STR_PAD_LEFT" );

   $firstip=substr($binip,0,$mask);

   return(strcmp($firstpart,$firstip)==0);

   }

?>



This function can be compacted, avoiding some variable settings, but the function will not be too clear to read...

Example code, used to made a kind of location service network-based:



<?php

$n = array ( "192.168.0.0/16"   => "TUSCANY",

             "192.168.1.0/24"   => "- Florence",

             "192.168.2.0/24"   => "- Pisa",

             "192.168.3.0/24"   => "- Siena",

             "192.168.64.0/21" => "- Tuscan Archipelago",

             "192.168.64.0/23" => "--- Elba Island",

             "192.168.66.0/24" => "--- Capraia Island",

             "192.168.67.0/24" => "--- Giannutri Island");



// Normally you should use the following line

$myip = $HTTP_SERVER_VARS['REMOTE_ADDR'];

// This is first example: returns Tuscany/Pisa

$myip = "192.168.2.33";

// This is second example: returns Tuscany/T.Arch./Elba

$myip = "192.168.65.34";



echo "Your position:<br />\n";

foreach ( $n as $k=>$v ) {

   list($net,$mask)=split("/",$k);

   if (isIPIn($myip,$net,$mask)) {

       echo $n[$k]."<br />\n"; }

   }

?>



and so on...

null at tty dot net dot ru
13-Oct-2003 04:51


Ported Net::Netmask perl module:

http://null.pp.ru/src/php/Netmask.phps

anderson at piq dot com dot br
06-Aug-2003 10:10


If you want to get the interface of an IP, based on the local route table, use this.



function GetIfaceforIP($user_ip)

{

    $route = "/bin/netstat -rn";



    exec($route, $aoutput);

    foreach($aoutput as $key => $line)

    {

        if($key > 1)

        {

            $line = ereg_replace("[[:space:]]+",",",$line);

            list($network, $gateway, $mask, $flags, $mss, $window, $irtt, $iface) = explode(",", $line)

            if((ip2long($user_ip) & ip2long($mask)) == ip2long($network))

            {

                return $iface;

            }

        }

    }

}

02-Apr-2003 08:11


Alternative cidr_conv function - a little easier to follow



function cidr_conv($cidr_address) {

  $first = substr($cidr_address, 0, strpos($cidr_address, "/"));

  $netmask = substr(strstr($cidr_address, "/"), 1);



  $first_bin = str_pad(decbin(ip2long($first)), 32, "0", STR_PAD_LEFT);

  $netmask_bin = str_pad(str_repeat("1", (integer)$netmask), 32, "0", STR_PAD_RIGHT);

  

  for ($i = 0; $i < 32; $i++) {

    if ($netmask_bin[$i] == "1") 

      $last_bin .= $first_bin[$i];

    else

      $last_bin .= "1";

  }



  $last = long2ip(bindec($last_bin));



  return "$first - $last";

}

trevor-hemsley at nospam dot dial dot pipex dot com
16-Oct-2002 11:53


Previous example of IP range to CIDR list does not cope with ranges as well as the perl Net::Netmask range2cidrlist() function. In PHP this looks like



<?

function imask($this)

{

// use base_convert not dechex because dechex is broken and returns 0x80000000 instead of 0xffffffff

return base_convert((pow(2,32) - pow(2, (32-$this)))), 10, 16);

}



function imaxblock($ibase, $tbit)

{

while ($tbit > 0)

{

$im = hexdec(imask($tbit-1));

$imand = $ibase & $im;

if ($imand != $ibase)

{

break;

}

$tbit--;

}

return $tbit;

}



function range2cidrlist($istart, $iend)

{

// this function returns an array of cidr lists that map the range given

$s = explode(".", $istart);

// PHP ip2long does not handle leading zeros on IP addresses! 172.016 comes back as 172.14, seems to be treated as octal!

$start = "";

$dot = "";

while (list($key,$val) = each($s))

{

$start = sprintf("%s%s%d",$start,$dot,$val);

$dot = ".";

}

$end = "";

$dot = "";

$e = explode(".",$iend);

while (list($key,$val) = each($e))

{

$end = sprintf("%s%s%d",$end,$dot,$val);

$dot = ".";

}

$start = ip2long($start);

$end = ip2long($end);

$result = array();

while ($end > $start)

{

$maxsize = imaxblock($start,32);

$x = log($end - $start + 1)/log(2);

$maxdiff = floor(32 - floor($x));

$ip = long2ip($start);

if ($maxsize < $maxdiff)

{

$maxsize = $maxdiff;

}

array_push($result,"$ip/$maxsize");

$start += pow(2, (32-$maxsize));

}

return $result;

}

?>

philippe-at-cyberabuse.org
12-Oct-2002 03:49


... and this one will do the opposite (o return NULL for invalid netblocks) :



1.0.0.0 1.0.255.255 -> 1.0.0.0/16

1.0.0.0 1.3.255.255 -> 1.0.0.0/14

192.168.0.0 192.168.0.255 -> 192.168.0.0/24



function ip2cidr($ip_start,$ip_end) {

if(long2ip(ip2long($ip_start))!=$ip_start or long2ip(ip2long($ip_end))!=$ip_end) return NULL; 

$ipl_start=(int)ip2long($ip_start);

$ipl_end=(int)ip2long($ip_end);

if($ipl_start>0 && $ipl_end<0) $delta=($ipl_end+4294967296)-$ipl_start;

else $delta=$ipl_end-$ipl_start;

$netmask=str_pad(decbin($delta),32,"0","STR_PAD_LEFT");

if(ip2long($ip_start)==0 && substr_count($netmask,"1")==32) return "0.0.0.0/0";

if($delta<0 or ($delta>0 && $delta%2==0)) return NULL;

for($mask=0;$mask<32;$mask++) if($netmask[$mask]==1) break;

if(substr_count($netmask,"0")!=$mask) return NULL;

return "$ip_start/$mask";

}

philippe-at-cyberabuse.org
14-Dec-2001 07:46


PHP miss CIDR functions.





This one will convert a CIDR like this:


0.0.0.0/16 -> 0.0.0.0 - 0.0.255.255


127.0/16 -> 127.0.0.0 - 127.0.255.255


etc...





function cidrconv($net) {


$start=strtok($net,"/");


$n=3-substr_count($net, ".");


if ($n>0) { for ($i=$n;$i>0;$i--) $start.=".0"; }


$bits1=str_pad(decbin(ip2long($start)),32,"0","STR_PAD_LEFT");


$net=pow(2,(32-substr(strstr($net,"/"),1)))-1;


$bits2=str_pad(decbin($net),32,"0","STR_PAD_LEFT");


for ($i=0;$i<32;$i++) {


if ($bits1[$i]==$bits2[$i]) $final.=$bits1[$i];


if ($bits1[$i]==1 and $bits2[$i]==0) $final.=$bits1[$i];


if ($bits1[$i]==0 and $bits2[$i]==1) $final.=$bits2[$i];


}


return $start." - ".long2ip(bindec($final));


}

add a note

checkdnsrr

muscat_setup

Last updated: Sat, 17 Jul 2004