From fd33d54f460bc7b89952b949524234b2408ec1ab Mon Sep 17 00:00:00 2001
From: Jack Yu <jackyu@google.com>
Date: Sun, 12 Dec 2021 13:34:53 -0800
Subject: [PATCH] Added IWLAN handover rules support

Support the new IWLAN handover rules to
allow/disallow handover based on different
scenarios.

Bug: 196597630
Test: atest DataNetworkControllerTest
Change-Id: Ic5584908131d4c8e0940f3d60def2dc74a7405d9
---
 .../telephony/AccessNetworkConstants.java     | 18 +++++++++++
 .../telephony/CarrierConfigManager.java       | 31 +++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/telephony/java/android/telephony/AccessNetworkConstants.java b/telephony/java/android/telephony/AccessNetworkConstants.java
index 1d7a4761dec6c..4469ffc144470 100644
--- a/telephony/java/android/telephony/AccessNetworkConstants.java
+++ b/telephony/java/android/telephony/AccessNetworkConstants.java
@@ -17,6 +17,7 @@
 package android.telephony;
 
 import android.annotation.IntDef;
+import android.annotation.NonNull;
 import android.annotation.SystemApi;
 import android.hardware.radio.V1_5.AccessNetwork;
 
@@ -28,6 +29,8 @@ import java.lang.annotation.RetentionPolicy;
  */
 public final class AccessNetworkConstants {
 
+    private static final String TAG = AccessNetworkConstants.class.getSimpleName();
+
     /**
      * Wireless transportation type
      *
@@ -108,6 +111,21 @@ public final class AccessNetworkConstants {
                 default: return Integer.toString(type);
             }
         }
+
+        /** @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;
+                default:
+                    Rlog.e(TAG, "Invalid access network type " + str);
+                    return UNKNOWN;
+            }
+        }
     }
 
     /**
diff --git a/telephony/java/android/telephony/CarrierConfigManager.java b/telephony/java/android/telephony/CarrierConfigManager.java
index 7d24b761b8148..1daa4cfe49bfb 100644
--- a/telephony/java/android/telephony/CarrierConfigManager.java
+++ b/telephony/java/android/telephony/CarrierConfigManager.java
@@ -5381,6 +5381,34 @@ public class CarrierConfigManager {
     public static final String KEY_UNTHROTTLE_DATA_RETRY_WHEN_TAC_CHANGES_BOOL =
             "unthrottle_data_retry_when_tac_changes_bool";
 
+    /**
+     * IWLAN handover rules that determine whether handover is allowed or disallowed between
+     * cellular and IWLAN.
+     *
+     * 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 -->
+     *     <item value="source=IWLAN, target=GERAN|UTRAN, type=disallowed"/>
+     *     <!-- Handover from 2G/3G to IWLAN is not allowed -->
+     *     <item value="source=GERAN|UTRAN, target:IWLAN, type=disallowed"/>
+     *     <!-- Handover from IWLAN to 3G/4G/5G is not allowed if the device is roaming. -->
+     *     <item value="source=IWLAN, target=UTRAN|EUTRAN|NGRAN, roaming=true, type=disallowed"/>
+     *     <!-- Handover from 4G to IWLAN is not allowed -->
+     *     <item value="source=EUTRAN, target=IWLAN, type=disallowed"/>
+     *     <!-- Handover is always allowed in any condition. -->
+     *     <item value="source=GERAN|UTRAN|EUTRAN|NGRAN|IWLAN,
+     *         target=GERAN|UTRAN|EUTRAN|NGRAN|IWLAN, type=allowed"/>
+     * </string-array>
+     *
+     * When handover is not allowed, frameworks will tear down the data network on source transport,
+     * and then setup a new one on the target transport when Qualified Network Service changes the
+     * preferred access networks for particular APN types.
+     *
+     * @hide
+     */
+    public static final String KEY_IWLAN_HANDOVER_POLICY_STRING_ARRAY =
+            "iwlan_handover_policy_string_array";
+
     /** The default value for every variable. */
     private final static PersistableBundle sDefaults;
 
@@ -6043,6 +6071,9 @@ public class CarrierConfigManager {
         sDefaults.putBoolean(KEY_UNTHROTTLE_DATA_RETRY_WHEN_TAC_CHANGES_BOOL, false);
         sDefaults.putBoolean(KEY_VONR_SETTING_VISIBILITY_BOOL, true);
         sDefaults.putBoolean(KEY_VONR_ENABLED_BOOL, false);
+        sDefaults.putStringArray(KEY_IWLAN_HANDOVER_POLICY_STRING_ARRAY, new String[]{
+                "source=GERAN|UTRAN|EUTRAN|NGRAN|IWLAN, "
+                        + "target=GERAN|UTRAN|EUTRAN|NGRAN|IWLAN, type=allowed"});
     }
 
     /**