php network functions

cidr2mask.php

<?php

function cidr2mask($netmask) {

$netmask_result="";
for($i=1; $i <= $netmask; $i++) {
  $netmask_result .= "1";
}

for($i=$netmask+1; $i <= 32; $i++) {
    $netmask_result .= "0";
}

$netmask_ip_binary_array = str_split( $netmask_result, 8 );

$netmask_ip_decimal_array = array();
foreach( $netmask_ip_binary_array as $k => $v ){
    $netmask_ip_decimal_array[$k] = bindec( $v ); // "100" => 4
}

$subnet = join( ".", $netmask_ip_decimal_array );

return $subnet;

}

echo cidr2mask("23");
?>

get_network_id.php

<?php

# REFERENCE - http://stackoverflow.com/questions/2942299/converting-cidr-address-to-subnet-mask-and-network-address

$ipNetmask = "192.168.1.12/16";
list($ip, $netmask) = split( "/", $ipNetmask );
$ip_elements_decimal = split( "[.]", $ip );
$netmask_result="";
for($i=1; $i <= $netmask; $i++) {
  $netmask_result .= "1";
}
for($i=$netmask+1; $i <= 32; $i++) {
    $netmask_result .= "0";
echo $netmask_result;
}
$netmask_ip_binary_array = str_split( $netmask_result, 8 );
$netmask_ip_decimal_array = array();
foreach( $netmask_ip_binary_array as $k => $v ){
    $netmask_ip_decimal_array[$k] = bindec( $v ); // "100" => 4
    $network_address_array[$k] = ( $netmask_ip_decimal_array[$k] & $ip_elements_decimal[$k] );
}
$network_address = join( ".", $network_address_array );

print_r($network_address);
?>

hostincidr.php

<?php

# REFERENCE http://stackoverflow.com/questions/594112/matching-an-ip-to-a-cidr-mask-in-php5

function cidr_match($ip, $range)
{
    list ($subnet, $bits) = split('/', $range);
    $ip = ip2long($ip);
    $subnet = ip2long($subnet);
    $mask = -1 << (32 - $bits);
    $subnet &= $mask; # nb: in case the supplied subnet wasn't correctly aligned
    return ($ip & $mask) == $subnet;
}

if (cidr_match("10.128.0.0", "10.128.1.0/16")) {
	echo 'match';
} else {
	echo 'no match';
}

echo cidr_match("10.128.0.0", "10.128.1.0/16");

?>

mask2cidr.php

<?php

function mask2cidr($mask) {

$mask = split( "[.]", $mask );

$bits = 0;

foreach ($mask as $octect) {
	$bin = decbin($octect);
	$bin = str_replace ( "0" , "" , $bin);
	$bits = $bits + strlen($bin);
}
	return $bits;
}

echo mask2cidr("255.255.252.0");

?>

string_is_ip.php

<?php

# Checks if string is in the right format to be an ip address

# Reference: http://php.net/manual/en/function.preg-match.php

function valid_ip($ip) { 
    return preg_match("/^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])" . 
            "(\.([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$/", $ip); 
}

echo valid_ip("192.168.10.10"); // 1 (true)

echo valid_ip("fruit"); // 0 (false)

echo valid_ip("999.999.999.999"); // 0 (false)

echo valid_ip("255.255.255.255"); // 1 (true)
?>