I already "did" this for IPv4;
$ip = '127.0.0.1'; // example
$ip = explode('.',$ip);
if( count($ip) != 4 ) $ip = array(0,0,0,0); // wrong ip format, default to 0.0.0.0
return chr($ip[0]) . chr($ip[1]) . chr($ip[2]) . chr($ip[3]);
I need to do the above for IPv6 as well. Reading through the IPv6 spec, (I admit I didn't read all of it), I saw several oddities ("exceptions") such as a set of 0 could be compressed to a double colon: ":0000:0000"=>"::" (if my understanding was correct). I also saw how you can have an IPv4-style string inside an IPv6 string: 0:0:0:0:0:0:127.0.0.1
Let's start by saying I've no freakin idea where to start.
Thanks to Alvaro, now I've got a pure-PHP implementation of inet_pton:
/**
* @copyright 2004-2007 Aidan Lister <aidan@php.net>, Arpad Ray <arpad@php.net>
* @link http://php.net/inet_pton
* @author Arpad Ray <arpad@php.net>
*/
function php_compat_inet_pton($address) {
$r = ip2long($address);
if ($r !== false && $r != -1) return pack('N', $r);
$delim_count = substr_count($address, ':');
if ($delim_count < 1 || $delim_count > 7) return false;
$r = explode(':', $address);
$rcount = count($r);
if (($doub = array_search('', $r, 1)) !== false) {
$length = (!$doub || $doub == $rcount - 1 ? 2 : 1);
array_splice($r, $doub, $length, array_fill(0, 8 + $length - $rcount, 0));
}
$r = array_map('hexdec', $r);
array_unshift($r, 'n*');
$r = call_user_func_array('pack', $r);
return $r;
}
Problem is, I can't quite understand what it's doing. The issue is, I can't just use such a function since (for one thing) I know it's packing the IP in a differnt format than I'm doing (or want to).
I will use the following URL to write the function I need:
http://www.zytrax.com/tech/protocols/ipv6.html
I will edit back with the function code.
Edit Here it goes: hope people find this useful.
class Connect {
/**
* Returns the IP in it's fullest format.
* @example
* ::1 => 0000:0000:0000:0000:0000:0000:0000:0001
* 220F::127.0.0.1 => 220F:0000:0000:0000:0000:0000:7F00:0001
* 2F:A1::1 => 002F:00A1:0000:0000:0000:0000:0000:0001
* @param string $ip Original/compressed/packed IPv6.
* @return string Full IP.
*/
protected static function fixIpv6($ip){
// fix double colon
if(strpos($ip,'::')!==false)$ip=str_replace('::',str_repeat(':',9-substr_count($ip,':')),$ip);
// fix each slot
$ip=explode(':',$ip);
foreach($ip as $k=>$v){
// fix empty/compressed slots
$ip[$k]=$v=str_pad($v,4,'0',STR_PAD_LEFT);
// fix ipv4-style slot
if(strpos($v,'.')!==false){
// initially empty buffer
$ip[$k]='';
// replace each number(byte) with a two-digit hex representation
foreach(explode('.',$v) as $v2){
$v=dechex(min((int)$v2,255));
if(strlen($v)==1)$v='0'.$v;
$ip[$k].=$v;
}
// add colon in between two pairs(bytes) (FFFFFFFF=>FFFF:FFFF)
$ip[$k]=implode(':',str_split($ip[$k],4));
}
}
return strtoupper(implode(':',$ip));
}
/**
* Compresses an IP to it's binary representation.
* @param string $ip A well-formatted full IPv4 or IPv6 address.
* @return string Binary representation of address.
*/
public static function compressIp($ip){
if(strpos($ip,':')!==false){ // ipv6
$ip=str_split(str_replace(':','',self::fixIpv6($ip)),2);
foreach($ip as $k=>$v)$ip[$k]=chr(hexdec($v));
return implode('',$ip);
}elseif(strpos($ip,'.')!==false){ // ipv4
$ip=explode('.',$ip);
if(count($ip)!=4)$ip=array(0,0,0,0);
return chr($ip[0]).chr($ip[1]).chr($ip[2]).chr($ip[3]);
}else throw new Exception('Unrecognized IP format: '.MB_SECURITY::snohtml($ip));
}
}