From 4bc1c1814d39d7aefcce23ad0bad35ebe4699ef3 Mon Sep 17 00:00:00 2001
From: Dan Guido <dan@trailofbits.com>
Date: Sun, 9 Apr 2017 09:52:23 -0400
Subject: [PATCH] Add configuration for URL probes to Apple profile

Chrome and Android both request a known URL that generates HTTP 204 No Content responses to determine if they have internet connectivity. In Apple profiles, we can use the same URL to determine whether the VPN needs to connect. Using this feature will help save battery life for lots of users.
---
 roles/vpn/templates/mobileconfig.j2 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/roles/vpn/templates/mobileconfig.j2 b/roles/vpn/templates/mobileconfig.j2
index c48bc1b9..ec41fa91 100644
--- a/roles/vpn/templates/mobileconfig.j2
+++ b/roles/vpn/templates/mobileconfig.j2
@@ -37,6 +37,8 @@
 {% endif %}
                     <key>InterfaceTypeMatch</key>
                       <string>WiFi</string>
+                    <key>URLStringProbe</key>
+                      <string>http://www.gstatic.com/generate_204</string>
                   </dict>
                   <dict>
                     <key>Action</key>
@@ -47,6 +49,8 @@
 {% endif %}
                     <key>InterfaceTypeMatch</key>
                       <string>Cellular</string>
+                    <key>URLStringProbe</key>
+                      <string>http://www.gstatic.com/generate_204</string>
                   </dict>
                 </array>
 {% else %}