From 054da30ba9eff11b6beb065dd42dfe7ee1b8003b Mon Sep 17 00:00:00 2001
From: Dan Poltawski <dan@moodle.com>
Date: Fri, 5 Feb 2016 14:56:01 +0000
Subject: [PATCH] MDL-48766 moodlelib: introduce ip_is_public()

For determining if an IP is publicly addressable
---
 lib/moodlelib.php            | 13 ++++++++--
 lib/tests/moodlelib_test.php | 48 ++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index fc0fc312a2e..0977ec1b16b 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -8641,8 +8641,6 @@ function getremoteaddr($default='0.0.0.0') {
 function cleanremoteaddr($addr, $compress=false) {
     $addr = trim($addr);
 
-    // TODO: maybe add a separate function is_addr_public() or something like this.
-
     if (strpos($addr, ':') !== false) {
         // Can be only IPv6.
         $parts = explode(':', $addr);
@@ -8735,6 +8733,17 @@ function cleanremoteaddr($addr, $compress=false) {
     return implode('.', $parts);
 }
 
+
+/**
+ * Is IP address a public address?
+ *
+ * @param string $ip The ip to check
+ * @return bool true if the ip is public
+ */
+function ip_is_public($ip) {
+    return (bool) filter_var($ip, FILTER_VALIDATE_IP, (FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE));
+}
+
 /**
  * This function will make a complete copy of anything it's given,
  * regardless of whether it's an object or not.
diff --git a/lib/tests/moodlelib_test.php b/lib/tests/moodlelib_test.php
index 353187e7225..d9c53fc0187 100644
--- a/lib/tests/moodlelib_test.php
+++ b/lib/tests/moodlelib_test.php
@@ -3130,4 +3130,52 @@ class core_moodlelib_testcase extends advanced_testcase {
         $this->assertSame('', $result);
         $this->assertDebuggingCalled();
     }
+
+    /**
+     * Data provider for private ips.
+     */
+    public function data_private_ips() {
+        return array(
+            array('10.0.0.0'),
+            array('172.16.0.0'),
+            array('192.168.1.0'),
+            array('fdfe:dcba:9876:ffff:fdc6:c46b:bb8f:7d4c'),
+            array('fdc6:c46b:bb8f:7d4c:fdc6:c46b:bb8f:7d4c'),
+            array('fdc6:c46b:bb8f:7d4c:0000:8a2e:0370:7334'),
+            array('127.0.0.1'), // This has been buggy in past: https://bugs.php.net/bug.php?id=53150.
+        );
+    }
+
+    /**
+     * Checks ip_is_public returns false for private ips.
+     *
+     * @param string $ip the ipaddress to test
+     * @dataProvider data_private_ips
+     */
+    public function test_ip_is_public_private_ips($ip) {
+        $this->assertFalse(ip_is_public($ip));
+    }
+
+    /**
+     * Data provider for public ips.
+     */
+    public function data_public_ips() {
+        return array(
+            array('2400:cb00:2048:1::8d65:71b3'),
+            array('2400:6180:0:d0::1b:2001'),
+            array('141.101.113.179'),
+            array('123.45.67.178'),
+        );
+    }
+
+    /**
+     * Checks ip_is_public returns true for public ips.
+     *
+     * @param string $ip the ipaddress to test
+     * @dataProvider data_public_ips
+     */
+    public function test_ip_is_public_public_ips($ip) {
+        $this->assertTrue(ip_is_public($ip));
+    }
+
 }
-- 
2.17.1