update IPUtils

src/Control/Util/IPUtils.php

@@ -1,4 +1,5 @@
 <?php
+
 /**
  * These helpful functions were lifted from the Symfony library
  * https://github.com/symfony/http-foundation/blob/master/LICENSE
@@ -7,6 +8,7 @@
  *
  * @author Fabien Potencier <[email protected]>
  */
+
 namespace SilverStripe\Control\Util;
 
 /**
@@ -131,4 +133,36 @@ public static function checkIP6($requestIP, $ip)
 
         return true;
     }
+
+    /**
+     * Anonymizes an IP/IPv6.
+     *
+     * Removes the last byte for v4 and the last 8 bytes for v6 IPs
+     */
+    public static function anonymize(string $ip): string
+    {
+        $wrappedIPv6 = false;
+        if (str_starts_with($ip, '[') && str_ends_with($ip, ']')) {
+            $wrappedIPv6 = true;
+            $ip = substr($ip, 1, -1);
+        }
+
+        $packedAddress = inet_pton($ip);
+        if (4 === \strlen($packedAddress)) {
+            $mask = '255.255.255.0';
+        } elseif ($ip === inet_ntop($packedAddress & inet_pton('::ffff:ffff:ffff'))) {
+            $mask = '::ffff:ffff:ff00';
+        } elseif ($ip === inet_ntop($packedAddress & inet_pton('::ffff:ffff'))) {
+            $mask = '::ffff:ff00';
+        } else {
+            $mask = 'ffff:ffff:ffff:ffff:0000:0000:0000:0000';
+        }
+        $ip = inet_ntop($packedAddress & inet_pton($mask));
+
+        if ($wrappedIPv6) {
+            $ip = '[' . $ip . ']';
+        }
+
+        return $ip;
+    }
 }