gistfile1.php

<?php

$ip = '2001:df0:1e::';
$ip2 = '2001:df0:1f::';
$prefix_len = 48;

 
/**
 * dtr_pton
 *
 * Converts a printable IP into an unpacked binary string
 *
 * @author Mike Mackintosh - mike@bakeryphp.com
 * @param string $ip
 * @return string $bin
 */
function dtr_pton( $ip ){
 
    if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)){
        return current( unpack( "A4", inet_pton( $ip ) ) );
    }
    elseif(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)){
        return current( unpack( "A16", inet_pton( $ip ) ) );
    }
 
    throw new \Exception("Please supply a valid IPv4 or IPv6 address");
 
    return false;
}

 
/**
 * dtr_ntop
 *
 * Converts an unpacked binary string into a printable IP
 *
 * @author Mike Mackintosh - mike@bakeryphp.com
 * @param string $str
 * @return string $ip
 */
function dtr_ntop( $str ){
    if( strlen( $str ) == 16 OR strlen( $str ) == 4 ){
        return inet_ntop( pack( "A".strlen( $str ) , $str ) );
    }
 
    throw new \Exception( "Please provide a 4 or 16 byte string" );
 
    return false;
}

function ipv6_p_mask_from_prefix_len($prefix_len) {
    $len = 128;
    $chars = array_fill(0, $len, '1');
    
    while ($prefix_len--) $chars[$len - $prefix_len] = '0';
    
    $bin_str = implode('', $chars);
    
    $bin_strs16 = str_split($bin_str, 16);
    
    $r = '';
    
    foreach ($bin_strs16 as $bs) {
        $r .= dechex(bindec( $bs ));
    }
    
    return implode(':', str_split($r, 4));
}

//$mask = ipv6_p_mask_from_prefix_len(4);
//$mask_n = dtr_pton($mask);
 $ip_n = dtr_pton($ip);
 $ip2_n = dtr_pton($ip2);

function is_addr_in_network($network_start_addr, $prefix_len, $ip) {
    $network_start_addr = dtr_pton($network_start_addr);
    $mask = dtr_pton(ipv6_p_mask_from_prefix_len($prefix_len)) && $network_start_addr;
    $ip = dtr_pton($ip);
    return $ip && $mask == $mask;
}

//< ipv6_p_mask_from_prefix_len(48)

//< is_addr_in_network('2001:df0:1e::', 113, '2001:df0:1e::1')
//< is_addr_in_network('::ffff:1.0.128.0', 113, '::ffff:1.0.120.2')