LXXXIII. 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.

Table 1. Network Configuration Options

Name	Default	Changeable	Changelog
define_syslog_variables	"0"	PHP_INI_ALL

For further details and definitions of the PHP_INI_* constants, see the Appendix H.

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.

Table 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

Table 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

Table 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

Table 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.

Table of Contents
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
inet_ntop -- Converts a packed internet address to a human readable representation
inet_pton -- Converts a human readable IP address to its packed in_addr representation
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

User Contributed Notes
Network Functions

nexxer at rogers dot com
24-Feb-2005 07:16


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 11:01


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 06:51


Ported Net::Netmask perl module:

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

anderson at piq dot com dot br
07-Aug-2003 12:10


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 10:11


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 01:53


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 05:49


... 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 09:46


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));


}

philip at cornado dot c()m
04-Jul-2001 04:20


More socket functions can be seen here :


http://www.php.net/manual/en/ref.sockets.php