/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.net;
import android.annotation.IntDef;
import android.annotation.IntRange;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.os.Binder;
import android.os.ParcelFileDescriptor;
import android.os.RemoteException;
import java.io.IOException;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.concurrent.Executor;
/**
* Allows applications to request that the system periodically send specific packets on their
* behalf, using hardware offload to save battery power.
*
* To request that the system send keepalives, call one of the methods that return a
* {@link SocketKeepalive} object, such as {@link ConnectivityManager#createSocketKeepalive},
* passing in a non-null callback. If the {@link SocketKeepalive} is successfully
* started, the callback's {@code onStarted} method will be called. If an error occurs,
* {@code onError} will be called, specifying one of the {@code ERROR_*} constants in this
* class.
*
* To stop an existing keepalive, call {@link SocketKeepalive#stop}. The system will call
* {@link SocketKeepalive.Callback#onStopped} if the operation was successful or
* {@link SocketKeepalive.Callback#onError} if an error occurred.
*
* For cellular, the device MUST support at least 1 keepalive slot.
*
* For WiFi, the device SHOULD support keepalive offload. If it does not, it MUST reply with
* {@link SocketKeepalive.Callback#onError} with {@code ERROR_UNSUPPORTED} to any keepalive offload
* request. If it does, it MUST support at least 3 concurrent keepalive slots.
*/
public abstract class SocketKeepalive implements AutoCloseable {
static final String TAG = "SocketKeepalive";
/** @hide */
public static final int SUCCESS = 0;
/** @hide */
public static final int NO_KEEPALIVE = -1;
/** @hide */
public static final int DATA_RECEIVED = -2;
/** @hide */
public static final int BINDER_DIED = -10;
/** The specified {@code Network} is not connected. */
public static final int ERROR_INVALID_NETWORK = -20;
/** The specified IP addresses are invalid. For example, the specified source IP address is
* not configured on the specified {@code Network}. */
public static final int ERROR_INVALID_IP_ADDRESS = -21;
/** The requested port is invalid. */
public static final int ERROR_INVALID_PORT = -22;
/** The packet length is invalid (e.g., too long). */
public static final int ERROR_INVALID_LENGTH = -23;
/** The packet transmission interval is invalid (e.g., too short). */
public static final int ERROR_INVALID_INTERVAL = -24;
/** The target socket is invalid. */
public static final int ERROR_INVALID_SOCKET = -25;
/** The target socket is not idle. */
public static final int ERROR_SOCKET_NOT_IDLE = -26;
/** The device does not support this request. */
public static final int ERROR_UNSUPPORTED = -30;
/** @hide TODO: delete when telephony code has been updated. */
public static final int ERROR_HARDWARE_UNSUPPORTED = ERROR_UNSUPPORTED;
/** The hardware returned an error. */
public static final int ERROR_HARDWARE_ERROR = -31;
/** The limitation of resource is reached. */
public static final int ERROR_INSUFFICIENT_RESOURCES = -32;
/** @hide */
@Retention(RetentionPolicy.SOURCE)
@IntDef(prefix = { "ERROR_" }, value = {
ERROR_INVALID_NETWORK,
ERROR_INVALID_IP_ADDRESS,
ERROR_INVALID_PORT,
ERROR_INVALID_LENGTH,
ERROR_INVALID_INTERVAL,
ERROR_INVALID_SOCKET,
ERROR_SOCKET_NOT_IDLE
})
public @interface ErrorCode {}
/**
* The minimum interval in seconds between keepalive packet transmissions.
*
* @hide
**/
public static final int MIN_INTERVAL_SEC = 10;
/**
* The maximum interval in seconds between keepalive packet transmissions.
*
* @hide
**/
public static final int MAX_INTERVAL_SEC = 3600;
/**
* An exception that embarks an error code.
* @hide
*/
public static class ErrorCodeException extends Exception {
public final int error;
public ErrorCodeException(final int error, final Throwable e) {
super(e);
this.error = error;
}
public ErrorCodeException(final int error) {
this.error = error;
}
}
/**
* This socket is invalid.
* See the error code for details, and the optional cause.
* @hide
*/
public static class InvalidSocketException extends ErrorCodeException {
public InvalidSocketException(final int error, final Throwable e) {
super(error, e);
}
public InvalidSocketException(final int error) {
super(error);
}
}
/**
* This packet is invalid.
* See the error code for details.
* @hide
*/
public static class InvalidPacketException extends ErrorCodeException {
public InvalidPacketException(final int error) {
super(error);
}
}
@NonNull final IConnectivityManager mService;
@NonNull final Network mNetwork;
@NonNull final ParcelFileDescriptor mPfd;
@NonNull final Executor mExecutor;
@NonNull final ISocketKeepaliveCallback mCallback;
// TODO: remove slot since mCallback could be used to identify which keepalive to stop.
@Nullable Integer mSlot;
SocketKeepalive(@NonNull IConnectivityManager service, @NonNull Network network,
@NonNull ParcelFileDescriptor pfd,
@NonNull Executor executor, @NonNull Callback callback) {
mService = service;
mNetwork = network;
mPfd = pfd;
mExecutor = executor;
mCallback = new ISocketKeepaliveCallback.Stub() {
@Override
public void onStarted(int slot) {
Binder.withCleanCallingIdentity(() ->
mExecutor.execute(() -> {
mSlot = slot;
callback.onStarted();
}));
}
@Override
public void onStopped() {
Binder.withCleanCallingIdentity(() ->
executor.execute(() -> {
mSlot = null;
callback.onStopped();
}));
}
@Override
public void onError(int error) {
Binder.withCleanCallingIdentity(() ->
executor.execute(() -> {
mSlot = null;
callback.onError(error);
}));
}
@Override
public void onDataReceived() {
Binder.withCleanCallingIdentity(() ->
executor.execute(() -> {
mSlot = null;
callback.onDataReceived();
}));
}
};
}
/**
* Request that keepalive be started with the given {@code intervalSec}. See
* {@link SocketKeepalive}. If the remote binder dies, or the binder call throws an exception
* when invoking start or stop of the {@link SocketKeepalive}, a {@link RemoteException} will be
* thrown into the {@code executor}. This is typically not important to catch because the remote
* party is the system, so if it is not in shape to communicate through binder the system is
* probably going down anyway. If the caller cares regardless, it can use a custom
* {@link Executor} to catch the {@link RemoteException}.
*
* @param intervalSec The target interval in seconds between keepalive packet transmissions.
* The interval should be between 10 seconds and 3600 seconds, otherwise
* {@link #ERROR_INVALID_INTERVAL} will be returned.
*/
public final void start(@IntRange(from = MIN_INTERVAL_SEC, to = MAX_INTERVAL_SEC)
int intervalSec) {
startImpl(intervalSec);
}
abstract void startImpl(int intervalSec);
/**
* Requests that keepalive be stopped. The application must wait for {@link Callback#onStopped}
* before using the object. See {@link SocketKeepalive}.
*/
public final void stop() {
stopImpl();
}
abstract void stopImpl();
/**
* Deactivate this {@link SocketKeepalive} and free allocated resources. The instance won't be
* usable again if {@code close()} is called.
*/
@Override
public final void close() {
stop();
try {
mPfd.close();
} catch (IOException e) {
// Nothing much can be done.
}
}
/**
* The callback which app can use to learn the status changes of {@link SocketKeepalive}. See
* {@link SocketKeepalive}.
*/
public static class Callback {
/** The requested keepalive was successfully started. */
public void onStarted() {}
/** The keepalive was successfully stopped. */
public void onStopped() {}
/** An error occurred. */
public void onError(@ErrorCode int error) {}
/** The keepalive on a TCP socket was stopped because the socket received data. This is
* never called for UDP sockets. */
public void onDataReceived() {}
}
}