<?php
// decbin32
// In order to simplify working with IP addresses (in binary) and their
// netmasks, it is easier to ensure that the binary strings are padded
// with zeros out to 32 characters - IP addresses are 32 bit numbers
function decbin32 ($dec) {
    return str_pad(decbin($dec), 32, '0', STR_PAD_LEFT);
}

// ipv4_in_range
// This function takes 2 arguments, an IP address and a "range" in several
// different formats.
// Network ranges can be specified as:
// 1. Wildcard format:     1.2.3.*
// 2. CIDR format:         1.2.3/24  OR  1.2.3.4/255.255.255.0
// 3. Start-End IP format: 1.2.3.0-1.2.3.255
// The function will return true if the supplied IP is within the range.
// Note little validation is done on the range inputs - it expects you to
// use one of the above 3 formats.
function ipv4_in_range($ip, $range) {
    if (strpos($range, '/') !== false) {
        // $range is in IP/NETMASK format
        list($range, $netmask) = explode('/', $range, 2);
        if (strpos($netmask, '.') !== false) {
            // $netmask is a 255.255.0.0 format
            $netmask = str_replace('*', '0', $netmask);
            $netmask_dec = ip2long($netmask);
            return ( (ip2long($ip) & $netmask_dec) == (ip2long($range) & $netmask_dec) );
        } else {
            // $netmask is a CIDR size block
            // fix the range argument
            $x = explode('.', $range);
            while(count($x)<4) $x[] = '0';
            list($a,$b,$c,$d) = $x;
            $range = sprintf("%u.%u.%u.%u", empty($a)?'0':$a, empty($b)?'0':$b,empty($c)?'0':$c,empty($d)?'0':$d);
            $range_dec = ip2long($range);
            $ip_dec = ip2long($ip);
            
            # Strategy 1 - Create the netmask with 'netmask' 1s and then fill it to 32 with 0s
            #$netmask_dec = bindec(str_pad('', $netmask, '1') . str_pad('', 32-$netmask, '0'));
            
            # Strategy 2 - Use math to create it
            $wildcard_dec = pow(2, (32-$netmask)) - 1;
            $netmask_dec = ~ $wildcard_dec;
            
            return (($ip_dec & $netmask_dec) == ($range_dec & $netmask_dec));
        }
    } else {
        // range might be 255.255.*.* or 1.2.3.0-1.2.3.255
        if (strpos($range, '*') !==false) { // a.b.*.* format
            // Just convert to A-B format by setting * to 0 for A and 255 for B
            $lower = str_replace('*', '0', $range);
            $upper = str_replace('*', '255', $range);
            $range = "$lower-$upper";
        }
        
        if (strpos($range, '-')!==false) { // A-B format
            list($lower, $upper) = explode('-', $range, 2);
            $lower_dec = (float)sprintf("%u",ip2long($lower));
            $upper_dec = (float)sprintf("%u",ip2long($upper));
            $ip_dec = (float)sprintf("%u",ip2long($ip));
            return ( ($ip_dec>=$lower_dec) && ($ip_dec<=$upper_dec) );
        }
        return false;
    } 
}

function ip2long6($ip) {
    if (substr_count($ip, '::')) { 
        $ip = str_replace('::', str_repeat(':0000', 8 - substr_count($ip, ':')) . ':', $ip); 
    } 
        
    $ip = explode(':', $ip);
    $r_ip = ''; 
    foreach ($ip as $v) {
        $r_ip .= str_pad(base_convert($v, 16, 2), 16, 0, STR_PAD_LEFT); 
    } 
        
    return base_convert($r_ip, 2, 10); 
} 

// Get the ipv6 full format and return it as a decimal value.
function get_ipv6_full($ip)
{
    $pieces = explode ("/", $ip, 2);
    $left_piece = $pieces[0];
    $right_piece = $pieces[1];

    // Extract out the main IP pieces
    $ip_pieces = explode("::", $left_piece, 2);
    $main_ip_piece = $ip_pieces[0];
    $last_ip_piece = $ip_pieces[1];

    // Pad out the shorthand entries.
    $main_ip_pieces = explode(":", $main_ip_piece);
    foreach($main_ip_pieces as $key=>$val) {
        $main_ip_pieces[$key] = str_pad($main_ip_pieces[$key], 4, "0", STR_PAD_LEFT);
    }

    // Check to see if the last IP block (part after ::) is set
    $last_piece = "";
    $size = count($main_ip_pieces);
    if (trim($last_ip_piece) != "") {
        $last_piece = str_pad($last_ip_piece, 4, "0", STR_PAD_LEFT);
    
        // Build the full form of the IPV6 address considering the last IP block set
        for ($i = $size; $i < 7; $i++) {
            $main_ip_pieces[$i] = "0000";
        }
        $main_ip_pieces[7] = $last_piece;
    }
    else {
        // Build the full form of the IPV6 address
        for ($i = $size; $i < 8; $i++) {
            $main_ip_pieces[$i] = "0000";
        }        
    }
    
    // Rebuild the final long form IPV6 address
    $final_ip = implode(":", $main_ip_pieces);

    return ip2long6($final_ip);
}


// Determine whether the IPV6 address is within range.
// $ip is the IPV6 address in decimal format to check if its within the IP range created by the cloudflare IPV6 address, $range_ip. 
// $ip and $range_ip are converted to full IPV6 format.
// Returns true if the IPV6 address, $ip,  is within the range from $range_ip.  False otherwise.
function ipv6_in_range($ip, $range_ip)
{
    $pieces = explode ("/", $range_ip, 2);
    $left_piece = $pieces[0];
    $right_piece = $pieces[1];

    // Extract out the main IP pieces
    $ip_pieces = explode("::", $left_piece, 2);
    $main_ip_piece = $ip_pieces[0];
    $last_ip_piece = $ip_pieces[1];

    // Pad out the shorthand entries.
    $main_ip_pieces = explode(":", $main_ip_piece);
    foreach($main_ip_pieces as $key=>$val) {
        $main_ip_pieces[$key] = str_pad($main_ip_pieces[$key], 4, "0", STR_PAD_LEFT);
    }

    // Create the first and last pieces that will denote the IPV6 range.
    $first = $main_ip_pieces;
    $last = $main_ip_pieces;

    // Check to see if the last IP block (part after ::) is set
    $last_piece = "";
    $size = count($main_ip_pieces);
    if (trim($last_ip_piece) != "") {
        $last_piece = str_pad($last_ip_piece, 4, "0", STR_PAD_LEFT);
    
        // Build the full form of the IPV6 address considering the last IP block set
        for ($i = $size; $i < 7; $i++) {
            $first[$i] = "0000";
            $last[$i] = "ffff";
        }
        $main_ip_pieces[7] = $last_piece;
    }
    else {
        // Build the full form of the IPV6 address
        for ($i = $size; $i < 8; $i++) {
            $first[$i] = "0000";
            $last[$i] = "ffff";
        }        
    }

    // Rebuild the final long form IPV6 address
    $first = ip2long6(implode(":", $first));
    $last = ip2long6(implode(":", $last));
    $in_range = ($ip >= $first && $ip <= $last);

    return $in_range;
}
?>