From d9ac485b1f804746a51da7f4f14578548fa4f5a7 Mon Sep 17 00:00:00 2001
From: Sarah Chin <sarahchin@google.com>
Date: Wed, 1 Jun 2022 17:08:53 -0700
Subject: [PATCH] Supported UNKNOWN in IWLAN handover rule

Extended handover rule to support the scenario that
handover should be blocked when source network goes
out of service.

Test: Basic testing + Wifi calling handover test + atest DataNetworkControllerTest
Bug: 234095834
Change-Id: I68c23f970af2a554ab438f630363be4591664cbb
---
 .../telephony/AccessNetworkConstants.java        | 16 ++++++++--------
 .../android/telephony/CarrierConfigManager.java  |  7 +++++++
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/telephony/java/android/telephony/AccessNetworkConstants.java b/telephony/java/android/telephony/AccessNetworkConstants.java
index 4469ffc144470..7eec86a40c130 100644
--- a/telephony/java/android/telephony/AccessNetworkConstants.java
+++ b/telephony/java/android/telephony/AccessNetworkConstants.java
@@ -115,15 +115,15 @@ public final class AccessNetworkConstants {
         /** @hide */
         public static @RadioAccessNetworkType int fromString(@NonNull String str) {
             switch (str.toUpperCase()) {
-                case "GERAN" : return GERAN;
-                case "UTRAN" : return UTRAN;
-                case "EUTRAN" : return EUTRAN;
-                case "CDMA2000" : return CDMA2000;
-                case "IWLAN" : return IWLAN;
-                case "NGRAN" : return NGRAN;
+                case "UNKNOWN": return UNKNOWN;
+                case "GERAN": return GERAN;
+                case "UTRAN": return UTRAN;
+                case "EUTRAN": return EUTRAN;
+                case "CDMA2000": return CDMA2000;
+                case "IWLAN": return IWLAN;
+                case "NGRAN": return NGRAN;
                 default:
-                    Rlog.e(TAG, "Invalid access network type " + str);
-                    return UNKNOWN;
+                    throw new IllegalArgumentException("Invalid access network type " + str);
             }
         }
     }
diff --git a/telephony/java/android/telephony/CarrierConfigManager.java b/telephony/java/android/telephony/CarrierConfigManager.java
index 70fe6b10ef20c..e032f65f34276 100644
--- a/telephony/java/android/telephony/CarrierConfigManager.java
+++ b/telephony/java/android/telephony/CarrierConfigManager.java
@@ -8550,6 +8550,13 @@ public class CarrierConfigManager {
      * IWLAN handover rules that determine whether handover is allowed or disallowed between
      * cellular and IWLAN.
      *
+     * Rule syntax: "source=[GERAN|UTRAN|EUTRAN|NGRAN|IWLAN|UNKNOWN], target=[GERAN|UTRAN|EUTRAN
+     * |NGRAN|IWLAN], type=[allowed|disallowed], roaming=[true|false], capabilities=[INTERNET|MMS
+     * |FOTA|IMS|CBS|SUPL|EIMS|XCAP|DUN]"
+     *
+     * Note that UNKNOWN can be only specified in the source access network and can be only used
+     * in the disallowed rule.
+     *
      * The handover rules will be matched in the order. Here are some sample rules.
      * <string-array name="iwlan_handover_rules" num="5">
      *     <!-- Handover from IWLAN to 2G/3G is not allowed -->