new function it::cidr_match($ip, $cidr)

1 files changed, 18 insertions, 0 deletions

diff --git a/it.class b/it.class
index 65a98f7..38421b4 100644
--- a/it.class
+++ b/it.class
@@ -315,6 +315,24 @@ static function toascii($text)
 
 
 /**
+ * Check whether an IP adress lies within a given range. Supports IPv4 and IPv6
+ * @param $ip IP address (192.168.42.123)
+ * @param $cidr IP range in CIDR notation (192.168.42.64/26)
+ * @return true if $ip is within $cidr
+ */
+function cidr_match($ip, $cidr)
+{
+	list($subnet, $mask) = explode('/', $cidr);
+	$ip_bin = inet_pton($ip);
+	$subnet_bin = inet_pton($subnet);
+	$valid_bytes = $mask >> 3;
+	$bitmask = 256 - (1 << (8 - ($mask & 7)));
+	$lastbyte_matched = $bitmask ? (ord($ip_bin{$valid_bytes}) & $bitmask) == (ord($subnet_bin{$valid_bytes}) & $bitmask) : true;
+	return substr($ip_bin, 0, $valid_bytes) == substr($subnet_bin, 0, $valid_bytes) && $lastbyte_matched;
+}
+
+
+/**
  * Convert regex for preg (adds and escapes delimiter, adds modifiers)
  * @param $pattern Regex to convert
  * @param $p['casesensitive'] Regex is case sensitive (omit modifier i)