Fix getIp for X-forwarded-for

Author: dfridrich

src/Lib.php

@@ -52,14 +52,98 @@ public static function getInstance()
      * Vrati IP adresu.
      *
      * @return string
+     * @see https://stackoverflow.com/a/28217316/993470
      */
     public static function getIp()
     {
-        if (isset($_SERVER['HTTP_X_FORWARDED_FOR']) && '' !== $_SERVER['HTTP_X_FORWARDED_FOR']) {
-            return $_SERVER['HTTP_X_FORWARDED_FOR'];
+        // Check for shared Internet/ISP IP
+        if (!empty($_SERVER['HTTP_CLIENT_IP']) && self::validateIp($_SERVER['HTTP_CLIENT_IP'])) {
+            return $_SERVER['HTTP_CLIENT_IP'];
         }
 
-        return @$_SERVER['REMOTE_ADDR'];
+        // Check for IP addresses passing through proxies
+        if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
+
+            // Check if multiple IP addresses exist in var
+            if (strpos($_SERVER['HTTP_X_FORWARDED_FOR'], ',') !== false) {
+                $iplist = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
+                foreach ($iplist as $ip) {
+                    if (validate_ip($ip)) {
+                        return $ip;
+                    }
+                }
+            } else {
+                if (validate_ip($_SERVER['HTTP_X_FORWARDED_FOR'])) {
+                    return $_SERVER['HTTP_X_FORWARDED_FOR'];
+                }
+            }
+        }
+        if (!empty($_SERVER['HTTP_X_FORWARDED']) && self::validateIp($_SERVER['HTTP_X_FORWARDED'])) {
+            return $_SERVER['HTTP_X_FORWARDED'];
+        }
+        if (!empty($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']) && self::validateIp($_SERVER['HTTP_X_CLUSTER_CLIENT_IP'])) {
+            return $_SERVER['HTTP_X_CLUSTER_CLIENT_IP'];
+        }
+        if (!empty($_SERVER['HTTP_FORWARDED_FOR']) && self::validateIp($_SERVER['HTTP_FORWARDED_FOR'])) {
+            return $_SERVER['HTTP_FORWARDED_FOR'];
+        }
+        if (!empty($_SERVER['HTTP_FORWARDED']) && self::validateIp($_SERVER['HTTP_FORWARDED'])) {
+            return $_SERVER['HTTP_FORWARDED'];
+        }
+
+        // Return unreliable IP address since all else failed
+        return $_SERVER['REMOTE_ADDR'];
+    }
+
+    /**
+     * Ensures an IP address is both a valid IP address and does not fall within
+     * a private network range.
+     */
+    public static function validateIp($ip)
+    {
+
+        if (strtolower($ip) === 'unknown') {
+            return false;
+        }
+
+        // Generate IPv4 network address
+        $ip = ip2long($ip);
+
+        // If the IP address is set and not equivalent to 255.255.255.255
+        if ($ip !== false && $ip !== -1) {
+            // Make sure to get unsigned long representation of IP address
+            // due to discrepancies between 32 and 64 bit OSes and
+            // signed numbers (ints default to signed in PHP)
+            $ip = sprintf('%u', $ip);
+
+            // Do private network range checking
+            if ($ip >= 0 && $ip <= 50331647) {
+                return false;
+            }
+            if ($ip >= 167772160 && $ip <= 184549375) {
+                return false;
+            }
+            if ($ip >= 2130706432 && $ip <= 2147483647) {
+                return false;
+            }
+            if ($ip >= 2851995648 && $ip <= 2852061183) {
+                return false;
+            }
+            if ($ip >= 2886729728 && $ip <= 2887778303) {
+                return false;
+            }
+            if ($ip >= 3221225984 && $ip <= 3221226239) {
+                return false;
+            }
+            if ($ip >= 3232235520 && $ip <= 3232301055) {
+                return false;
+            }
+            if ($ip >= 4294967040) {
+                return false;
+            }
+        }
+
+        return true;
     }
 
     /**
@@ -1237,8 +1321,8 @@ public static function parseStringForSearch($string)
         }
 
         return $conditions;
-    }    
-	
+    }
+
     /**
      * @param string $input
      * @param int $rowLength
@@ -1249,7 +1333,7 @@ public static function wrapPlainText($input, $rowLength = 50)
         $words = explode(' ', $input);
         $rows = [];
         $row = '';
-    
+
         foreach ($words as $word) {
             if (strlen($row . ' ' . $word) > $rowLength) {
                 $rows[] = trim($row);
@@ -1258,7 +1342,7 @@ public static function wrapPlainText($input, $rowLength = 50)
             $row .= ' ' . $word;
         }
         $rows[] = trim($row);
-    
+
         return implode("\n", $rows);
     }