Created new public API so applications can customize its metered network

usage while running in background.

The new API is 'int getRestrictBackgroundStatus()' and returns the
following values:

 - RESTRICT_BACKGROUND_STATUS_DISABLED: no restrictions
 - RESTRICT_BACKGROUND_STATUS_WHITELISTED: restriction but app is
   whitelisted
 - RESTRICT_BACKGROUND_STATUS_ENABLED: full restriction

The proper way to interprete these values for using metered networks
while running on background is:

 - When disabled, there is no restriction and the application could use the
   metered networks freely.

 - When whitelisted, the application can use the metered network, but should try
   to minimize the usage.

 - When enabled, the application should not try to use metered networks at
   all, since the usage will be denied.

BUG: 26451391
Change-Id: If07d42bb88e4c02802df0234861f38aef2cfead7

6 files changed, 102 insertions, 1 deletions

diff --git a/api/current.txt b/api/current.txt
index e50eba11393f..99195baa4d39 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -22760,6 +22760,7 @@ package android.net {
     method public android.net.NetworkInfo getNetworkInfo(android.net.Network);
     method public deprecated int getNetworkPreference();
     method public static deprecated android.net.Network getProcessDefaultNetwork();
+    method public int getRestrictBackgroundStatus();
     method public boolean isActiveNetworkMetered();
     method public boolean isDefaultNetworkActive();
     method public static deprecated boolean isNetworkTypeValid(int);
@@ -22794,6 +22795,9 @@ package android.net {
     field public static final java.lang.String EXTRA_NO_CONNECTIVITY = "noConnectivity";
     field public static final java.lang.String EXTRA_OTHER_NETWORK_INFO = "otherNetwork";
     field public static final java.lang.String EXTRA_REASON = "reason";
+    field public static final int RESTRICT_BACKGROUND_STATUS_DISABLED = 1; // 0x1
+    field public static final int RESTRICT_BACKGROUND_STATUS_ENABLED = 3; // 0x3
+    field public static final int RESTRICT_BACKGROUND_STATUS_WHITELISTED = 2; // 0x2
     field public static final int TYPE_BLUETOOTH = 7; // 0x7
     field public static final int TYPE_DUMMY = 8; // 0x8
     field public static final int TYPE_ETHERNET = 9; // 0x9
@@ -22820,6 +22824,9 @@ package android.net {
     method public abstract void onNetworkActive();
   }
 
+  public static abstract class ConnectivityManager.RestrictBackgroundStatus implements java.lang.annotation.Annotation {
+  }
+
   public class Credentials {
     ctor public Credentials(int, int, int);
     method public int getGid();
diff --git a/api/system-current.txt b/api/system-current.txt
index 2d358bfe0bf8..abdf6804df48 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -24348,6 +24348,7 @@ package android.net {
     method public android.net.NetworkInfo getNetworkInfo(android.net.Network);
     method public deprecated int getNetworkPreference();
     method public static deprecated android.net.Network getProcessDefaultNetwork();
+    method public int getRestrictBackgroundStatus();
     method public boolean isActiveNetworkMetered();
     method public boolean isDefaultNetworkActive();
     method public static deprecated boolean isNetworkTypeValid(int);
@@ -24382,6 +24383,9 @@ package android.net {
     field public static final java.lang.String EXTRA_NO_CONNECTIVITY = "noConnectivity";
     field public static final java.lang.String EXTRA_OTHER_NETWORK_INFO = "otherNetwork";
     field public static final java.lang.String EXTRA_REASON = "reason";
+    field public static final int RESTRICT_BACKGROUND_STATUS_DISABLED = 1; // 0x1
+    field public static final int RESTRICT_BACKGROUND_STATUS_ENABLED = 3; // 0x3
+    field public static final int RESTRICT_BACKGROUND_STATUS_WHITELISTED = 2; // 0x2
     field public static final int TYPE_BLUETOOTH = 7; // 0x7
     field public static final int TYPE_DUMMY = 8; // 0x8
     field public static final int TYPE_ETHERNET = 9; // 0x9
@@ -24408,6 +24412,9 @@ package android.net {
     method public abstract void onNetworkActive();
   }
 
+  public static abstract class ConnectivityManager.RestrictBackgroundStatus implements java.lang.annotation.Annotation {
+  }
+
   public class Credentials {
     ctor public Credentials(int, int, int);
     method public int getGid();
diff --git a/api/test-current.txt b/api/test-current.txt
index bcdf5c1b22d9..7c967999619f 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -22768,6 +22768,7 @@ package android.net {
     method public android.net.NetworkInfo getNetworkInfo(android.net.Network);
     method public deprecated int getNetworkPreference();
     method public static deprecated android.net.Network getProcessDefaultNetwork();
+    method public int getRestrictBackgroundStatus();
     method public boolean isActiveNetworkMetered();
     method public boolean isDefaultNetworkActive();
     method public static deprecated boolean isNetworkTypeValid(int);
@@ -22802,6 +22803,9 @@ package android.net {
     field public static final java.lang.String EXTRA_NO_CONNECTIVITY = "noConnectivity";
     field public static final java.lang.String EXTRA_OTHER_NETWORK_INFO = "otherNetwork";
     field public static final java.lang.String EXTRA_REASON = "reason";
+    field public static final int RESTRICT_BACKGROUND_STATUS_DISABLED = 1; // 0x1
+    field public static final int RESTRICT_BACKGROUND_STATUS_ENABLED = 3; // 0x3
+    field public static final int RESTRICT_BACKGROUND_STATUS_WHITELISTED = 2; // 0x2
     field public static final int TYPE_BLUETOOTH = 7; // 0x7
     field public static final int TYPE_DUMMY = 8; // 0x8
     field public static final int TYPE_ETHERNET = 9; // 0x9
@@ -22828,6 +22832,9 @@ package android.net {
     method public abstract void onNetworkActive();
   }
 
+  public static abstract class ConnectivityManager.RestrictBackgroundStatus implements java.lang.annotation.Annotation {
+  }
+
   public class Credentials {
     ctor public Credentials(int, int, int);
     method public int getGid();
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index c4f0847e694b..5584cde2aa6c 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -16,7 +16,7 @@
 package android.net;
 
 import static com.android.internal.util.Preconditions.checkNotNull;
-
+import android.annotation.IntDef;
 import android.annotation.Nullable;
 import android.annotation.SdkConstant;
 import android.annotation.SdkConstant.SdkConstantType;
@@ -49,6 +49,8 @@ import com.android.internal.util.Protocol;
 
 import libcore.net.event.NetworkEventDispatcher;
 
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.net.InetAddress;
 import java.util.HashMap;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -512,6 +514,7 @@ public class ConnectivityManager {
     private final Context mContext;
 
     private INetworkManagementService mNMService;
+    private INetworkPolicyManager mNPManager;
 
     /**
      * Tests if a given integer represents a valid network type.
@@ -3025,4 +3028,58 @@ public class ConnectivityManager {
         return NetworkUtils.bindProcessToNetworkForHostResolution(
                 network == null ? NETID_UNSET : network.netId);
     }
+
+    /**
+     * Device is not restricting metered network activity while application is running on
+     * background.
+     */
+    public static final int RESTRICT_BACKGROUND_STATUS_DISABLED = 1;
+
+    /**
+     * Device is restricting metered network activity while application is running on background,
+     * but application is allowed to bypass it.
+     * <p>
+     * In this state, application should take action to mitigate metered network access.
+     * For example, a music streaming application should switch to a low-bandwidth bitrate.
+     */
+    public static final int RESTRICT_BACKGROUND_STATUS_WHITELISTED = 2;
+
+    /**
+     * Device is restricting metered network activity while application is running on background.
+     * In this state, application should not try to use the network while running on background,
+     * because it would be denied.
+     */
+    public static final int RESTRICT_BACKGROUND_STATUS_ENABLED = 3;
+
+    @IntDef(flag = false, value = {
+            RESTRICT_BACKGROUND_STATUS_DISABLED,
+            RESTRICT_BACKGROUND_STATUS_WHITELISTED,
+            RESTRICT_BACKGROUND_STATUS_ENABLED,
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface RestrictBackgroundStatus {
+    }
+
+    private INetworkPolicyManager getNetworkPolicyManager() {
+        synchronized (this) {
+            if (mNPManager != null) {
+                return mNPManager;
+            }
+            mNPManager = INetworkPolicyManager.Stub.asInterface(ServiceManager
+                    .getService(Context.NETWORK_POLICY_SERVICE));
+            return mNPManager;
+        }
+    }
+
+    /**
+     * Determines if the calling application is subject to metered network restrictions while
+     * running on background.
+     */
+    public @RestrictBackgroundStatus int getRestrictBackgroundStatus() {
+        try {
+            return getNetworkPolicyManager().getRestrictBackgroundByCaller();
+        } catch (RemoteException e) {
+            return RESTRICT_BACKGROUND_STATUS_DISABLED;
+        }
+    }
 }
diff --git a/core/java/android/net/INetworkPolicyManager.aidl b/core/java/android/net/INetworkPolicyManager.aidl
index 06aa616b9317..a57fac3afe6c 100644
--- a/core/java/android/net/INetworkPolicyManager.aidl
+++ b/core/java/android/net/INetworkPolicyManager.aidl
@@ -56,6 +56,12 @@ interface INetworkPolicyManager {
     void addRestrictBackgroundWhitelistedUid(int uid);
     void removeRestrictBackgroundWhitelistedUid(int uid);
     int[] getRestrictBackgroundWhitelistedUids();
+    /** Gets the restrict background status based on the caller's UID:
+        1 - disabled
+        2 - whitelisted
+        3 - enabled
+    */
+    int getRestrictBackgroundByCaller();
 
     void setDeviceIdleMode(boolean enabled);
 
diff --git a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
index 38ebc8003bc7..26584896460e 100644
--- a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
+++ b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
@@ -31,6 +31,9 @@ import static android.content.Intent.EXTRA_UID;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.TYPE_MOBILE;
 import static android.net.ConnectivityManager.TYPE_WIMAX;
+import static android.net.ConnectivityManager.RESTRICT_BACKGROUND_STATUS_DISABLED;
+import static android.net.ConnectivityManager.RESTRICT_BACKGROUND_STATUS_ENABLED;
+import static android.net.ConnectivityManager.RESTRICT_BACKGROUND_STATUS_WHITELISTED;
 import static android.net.ConnectivityManager.isNetworkTypeMobile;
 import static android.net.NetworkPolicy.CYCLE_NONE;
 import static android.net.NetworkPolicy.LIMIT_DISABLED;
@@ -1873,6 +1876,20 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub {
     }
 
     @Override
+    public int getRestrictBackgroundByCaller() {
+        mContext.enforceCallingOrSelfPermission(ACCESS_NETWORK_STATE, TAG);
+        final int uid = Binder.getCallingUid();
+        synchronized (mRulesLock) {
+            if (!mRestrictBackground) {
+                return RESTRICT_BACKGROUND_STATUS_DISABLED;
+            }
+            return mRestrictBackgroundWhitelistUids.get(uid)
+                    ? RESTRICT_BACKGROUND_STATUS_WHITELISTED
+                    : RESTRICT_BACKGROUND_STATUS_ENABLED;
+        }
+    }
+
+    @Override
     public boolean getRestrictBackground() {
         mContext.enforceCallingOrSelfPermission(MANAGE_NETWORK_POLICY, TAG);