Clean up duplicate code for IPv6

inc/functions.php

@@ -12,6 +12,8 @@ if (realpath($_SERVER['SCRIPT_FILENAME']) == str_replace('\\', '/', __FILE__)) {
 
 $microtime_start = microtime(true);
 
+use Lifo\IP\IP; // for expanding IPv6 address in DNSBL()
+
 // the user is not currently logged in as a moderator
 $mod = false;
 
@@ -2271,23 +2273,7 @@ function ReverseIPv4Octets($ip) {
 }
 
 function ReverseIPv6Octets($ip) {
-	return strrev(implode(".", str_split(str_replace(':', '', inet_expand($ip)))));
-}
-
-// copypastad from lib/IP/Lifo/IP.php, TODO replace this with a proper include
-function inet_expand($ip)
-{
-	// strip possible cidr notation off
-	if (($pos = strpos($ip, '/')) !== false) {
-		$ip = substr($ip, 0, $pos);
-	}
-	$bytes = unpack('n*', inet_pton($ip));
-	if (count($bytes) > 2) {
-		return implode(':', array_map(function ($b) {
-			return sprintf("%04x", $b);
-		}, $bytes));
-	}
-	return $ip;
+	return strrev(implode(".", str_split(str_replace(':', '', IP::inet_expand($ip)))));
 }
 
 function wordfilters(&$body) {