commit 4a3406799000e8f81b4b54cd8ba43bd8f8bd029b
author chiachangwang <chiachangwang@google.com> Thu May 11 02:42:59 2023 +0000
committer chiachangwang <chiachangwang@google.com> Thu May 11 02:42:59 2023 +0000
tree d0144e13a4d1aa8a1fb7a15b061a5eea142b958a
parent 62434fd9fe6338b0355506b31fa4a9e733b0c030

Change default IP protocol preference from AUTO to IPV4

By default, PREFERRED_IKE_PROTOCOL_IPV4_UDP is used for safety.
This is because some carriers' networks do not support IPv6 very
well, and using IPv4 can help to prevent problems.

Carrierconfig customization on the device should override the
value if V6 are known to work well.

Bug: 269714970
Test: atest FrameworksNetTests
Change-Id: Ia0a6bd11d25fd67edb0a301e81626ec4f174155a

services/core/java/com/android/server/connectivity/Vpn.java

diff --git a/services/core/java/com/android/server/connectivity/Vpn.java b/services/core/java/com/android/server/connectivity/Vpn.java
index c678a92..4208a12 100644
--- a/services/core/java/com/android/server/connectivity/Vpn.java
+++ b/services/core/java/com/android/server/connectivity/Vpn.java
@@ -3677,8 +3677,11 @@
                     encapType = IkeSessionParams.ESP_ENCAP_TYPE_NONE;
                     break;
                 default:
-                    ipVersion = IkeSessionParams.ESP_IP_VERSION_AUTO;
-                    encapType = IkeSessionParams.ESP_ENCAP_TYPE_AUTO;
+                    // By default, PREFERRED_IKE_PROTOCOL_IPV4_UDP is used for safety. This is
+                    // because some carriers' networks do not support IPv6 very well, and using
+                    // IPv4 can help to prevent problems.
+                    ipVersion = IkeSessionParams.ESP_IP_VERSION_IPV4;
+                    encapType = IkeSessionParams.ESP_ENCAP_TYPE_UDP;
                     break;
             }
             return new CarrierConfigInfo(mccMnc, natKeepalive, encapType, ipVersion);