Add `\wcf\util\IpAddress`

diff --git a/wcfsetup/install/files/lib/util/IpAddress.class.php b/wcfsetup/install/files/lib/util/IpAddress.class.php
new file mode 100644 (file)
index 0000000..061c2b8
--- /dev/null
+++ b/wcfsetup/install/files/lib/util/IpAddress.class.php
@@ -0,0 +1,126 @@
+<?php
+
+namespace wcf\util;
+
+/**
+ * Represents an IP address.
+ *
+ * @author  Tim Duesterhus
+ * @copyright   2001-2021 WoltLab GmbH
+ * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package WoltLabSuite\Core\Util
+ * @since       5.4
+ */
+final class IpAddress
+{
+    /**
+     * @var string
+     */
+    private $ipAddress;
+
+    public function __construct(string $ipAddress)
+    {
+        if (\filter_var($ipAddress, \FILTER_VALIDATE_IP) === false) {
+            throw new \InvalidArgumentException(\sprintf(
+                "The given IP address '%s' is not a valid IP address.",
+                $ipAddress
+            ));
+        }
+
+        $this->ipAddress = $ipAddress;
+    }
+
+    /**
+     * Returns the IP address in IPv6 form. An IPv4 address will be returned as
+     * an IPv4-mapped address.
+     */
+    public function asV6(): self
+    {
+        return new self(UserUtil::convertIPv4To6($this->ipAddress));
+    }
+
+    /**
+     * Returns the IP address in IPv4 form. Null will be returned if the IP address
+     * is neither an IPv4 address, nor an IPv4-mapped address.
+     */
+    public function asV4(): ?self
+    {
+        // Return an IPv4 as-is.
+        if (\filter_var($this->ipAddress, \FILTER_VALIDATE_IP, \FILTER_FLAG_IPV4) !== false) {
+            return $this;
+        }
+
+        // Check for an IPv4-mapped address.
+        $ip = $this->ipAddress;
+        if (\substr($ip, 0, 7) == '::ffff:') {
+            $ip = \substr($ip, 7);
+            if (\preg_match('~^([a-f0-9]{1,4}):([a-f0-9]{1,4})$~', $ip, $matches)) {
+                $ip = [
+                    \base_convert($matches[1], 16, 10),
+                    \base_convert($matches[2], 16, 10),
+                ];
+
+                $ipParts = [];
+                $tmp = $ip[0] % 256;
+                $ipParts[] = ($ip[0] - $tmp) / 256;
+                $ipParts[] = $tmp;
+                $tmp = $ip[1] % 256;
+                $ipParts[] = ($ip[1] - $tmp) / 256;
+                $ipParts[] = $tmp;
+
+                return new self(\implode('.', $ipParts));
+            }
+
+            return new self($ip);
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns a new IP address with the last $maskX bits masked off.
+     */
+    public function mask(int $mask4, int $mask6): self
+    {
+        if ($mask4 < 0 || $mask4 > 32) {
+            throw new \InvalidArgumentException('Given $mask4 is not in the interval [0, 32].');
+        }
+        if ($mask6 < 0 || $mask6 > 128) {
+            throw new \InvalidArgumentException('Given $mask6 is not in the interval [0, 128].');
+        }
+
+        $ipAddress = $this->asV4();
+
+        if ($ipAddress === null) {
+            $ipAddress = $this->asV6();
+            $maskBits = $mask6;
+            $bytes = 16;
+        } else {
+            $maskBits = $mask4;
+            $bytes = 4;
+        }
+
+        $mask = '';
+        for ($i = 0; $i < $bytes; $i++, $maskBits -= 8) {
+            $mask .= \chr(0xff << (8 - \min(8, $maskBits)));
+        }
+
+        return new self(\inet_ntop(\inet_pton((string)$ipAddress) & $mask));
+    }
+
+    /**
+     * @see IpAddress::getIpAddress()
+     */
+    public function __toString(): string
+    {
+        return $this->getIpAddress();
+    }
+
+    /**
+     * Returns the raw IP address that was used to construct this instance.
+     */
+    public function getIpAddress(): string
+    {
+        return $this->ipAddress;
+    }
+}