[inc/IpUtil] Add missing class

1 files changed, 72 insertions, 0 deletions

diff --git a/inc/iputil.inc.php b/inc/iputil.inc.php
new file mode 100644
index 00000000..5cdd583c
--- /dev/null
+++ b/inc/iputil.inc.php
@@ -0,0 +1,72 @@
+<?php
+
+class IpUtil
+{
+
+	public static function rangeToCidr($start, $end)
+	{
+		$value = (int)$start ^ (int)$end;
+		if (!self::isAllOnes($value))
+			return 'NOT SUBNET: ' . long2ip($start) . '-' . long2ip($end);
+		$ones = self::countOnes($value);
+		return long2ip($start) . '/' . (32 - $ones);
+	}
+
+	public static function isValidSubnetRange($start, $end)
+	{
+		return self::isAllOnes((int)$start ^ (int)$end);
+	}
+
+	/**
+	 * Return number of one bits required to represent
+	 * this number. Assumes given number is 2^n - 1.
+	 */
+	private static function countOnes($value)
+	{
+		// This is log(value) / log(2)
+		// It should actually be $value + 1, but floating point errors
+		// start to happen either way at higher values, so with
+		// the round() thrown in, it doesn't matter...
+		return round(log($value) / 0.69314718055995);
+	}
+
+	/**
+	 * Is the given number just ones if converted to
+	 * binary (ignoring leading zeros)?
+	 */
+	private static function isAllOnes($value)
+	{
+		return ($value & ($value + 1)) === 0;
+	}
+
+	/**
+	 * Parse network range in CIDR notion, return
+	 * ['start' => (int), 'end' => (int)] representing
+	 * the according start and end addresses as integer
+	 * values. Returns false on malformed input.
+	 * @param string $cidr 192.168.101/24, 1.2.3.4/16, ...
+	 * @return array|false start and end address, false on error
+	 */
+	public static function parseCidr($cidr)
+	{
+		$parts = explode('/', $cidr);
+		if (count($parts) !== 2)
+			return false;
+		$ip = $parts[0];
+		$bits = $parts[1];
+		if (!is_numeric($bits) || $bits < 0 || $bits > 32)
+			return false;
+		$dots = substr_count($ip, '.');
+		if ($dots < 3) {
+			$ip .= str_repeat('.0', 3 - $dots);
+		}
+		$ip = ip2long($ip);
+		if ($ip === false)
+			return false;
+		$bits = pow(2, 32 - $bits) - 1;
+		if (PHP_INT_SIZE === 4)
+			return ['start' => sprintf('%u', $ip & ~$bits), 'end' => sprintf('%u', $ip | $bits)];
+		return ['start' => $ip & ~$bits, 'end' => $ip | $bits];
+	}
+
+}