/*
* Copyright (C) 2014 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.UnsupportedAppUsage;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.Messenger;
import android.util.Log;
import com.android.internal.util.AsyncChannel;
import com.android.internal.util.Protocol;
import java.util.ArrayList;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* A Utility class for handling for communicating between bearer-specific
* code and ConnectivityService.
*
* A bearer may have more than one NetworkAgent if it can simultaneously
* support separate networks (IMS / Internet / MMS Apns on cellular, or
* perhaps connections with different SSID or P2P for Wi-Fi).
*
* @hide
*/
public abstract class NetworkAgent extends Handler {
// Guaranteed to be valid (not NETID_UNSET), otherwise registerNetworkAgent() would have thrown
// an exception.
public final int netId;
private volatile AsyncChannel mAsyncChannel;
private final String LOG_TAG;
private static final boolean DBG = true;
private static final boolean VDBG = false;
private final Context mContext;
private final ArrayList<Message>mPreConnectedQueue = new ArrayList<Message>();
private volatile long mLastBwRefreshTime = 0;
private static final long BW_REFRESH_MIN_WIN_MS = 500;
private boolean mPollLceScheduled = false;
private AtomicBoolean mPollLcePending = new AtomicBoolean(false);
public final int mFactorySerialNumber;
private static final int BASE = Protocol.BASE_NETWORK_AGENT;
/**
* Sent by ConnectivityService to the NetworkAgent to inform it of
* suspected connectivity problems on its network. The NetworkAgent
* should take steps to verify and correct connectivity.
*/
public static final int CMD_SUSPECT_BAD = BASE;
/**
* Sent by the NetworkAgent (note the EVENT vs CMD prefix) to
* ConnectivityService to pass the current NetworkInfo (connection state).
* Sent when the NetworkInfo changes, mainly due to change of state.
* obj = NetworkInfo
*/
public static final int EVENT_NETWORK_INFO_CHANGED = BASE + 1;
/**
* Sent by the NetworkAgent to ConnectivityService to pass the current
* NetworkCapabilties.
* obj = NetworkCapabilities
*/
public static final int EVENT_NETWORK_CAPABILITIES_CHANGED = BASE + 2;
/**
* Sent by the NetworkAgent to ConnectivityService to pass the current
* NetworkProperties.
* obj = NetworkProperties
*/
public static final int EVENT_NETWORK_PROPERTIES_CHANGED = BASE + 3;
/* centralize place where base network score, and network score scaling, will be
* stored, so as we can consistently compare apple and oranges, or wifi, ethernet and LTE
*/
public static final int WIFI_BASE_SCORE = 60;
/**
* Sent by the NetworkAgent to ConnectivityService to pass the current
* network score.
* obj = network score Integer
*/
public static final int EVENT_NETWORK_SCORE_CHANGED = BASE + 4;
/**
* Sent by ConnectivityService to the NetworkAgent to inform the agent of the
* networks status - whether we could use the network or could not, due to
* either a bad network configuration (no internet link) or captive portal.
*
* arg1 = either {@code VALID_NETWORK} or {@code INVALID_NETWORK}
* obj = Bundle containing map from {@code REDIRECT_URL_KEY} to {@code String}
* representing URL that Internet probe was redirect to, if it was redirected,
* or mapping to {@code null} otherwise.
*/
public static final int CMD_REPORT_NETWORK_STATUS = BASE + 7;
public static final int VALID_NETWORK = 1;
public static final int INVALID_NETWORK = 2;
public static String REDIRECT_URL_KEY = "redirect URL";
/**
* Sent by the NetworkAgent to ConnectivityService to indicate this network was
* explicitly selected. This should be sent before the NetworkInfo is marked
* CONNECTED so it can be given special treatment at that time.
*
* obj = boolean indicating whether to use this network even if unvalidated
*/
public static final int EVENT_SET_EXPLICITLY_SELECTED = BASE + 8;
/**
* Sent by ConnectivityService to the NetworkAgent to inform the agent of
* whether the network should in the future be used even if not validated.
* This decision is made by the user, but it is the network transport's
* responsibility to remember it.
*
* arg1 = 1 if true, 0 if false
*/
public static final int CMD_SAVE_ACCEPT_UNVALIDATED = BASE + 9;
/**
* Sent by ConnectivityService to the NetworkAgent to inform the agent to pull
* the underlying network connection for updated bandwidth information.
*/
public static final int CMD_REQUEST_BANDWIDTH_UPDATE = BASE + 10;
/**
* Sent by ConnectivityService to the NetworkAgent to request that the specified packet be sent
* periodically on the given interval.
*
* arg1 = the slot number of the keepalive to start
* arg2 = interval in seconds
* obj = KeepalivePacketData object describing the data to be sent
*
* Also used internally by ConnectivityService / KeepaliveTracker, with different semantics.
*/
public static final int CMD_START_SOCKET_KEEPALIVE = BASE + 11;
/**
* Requests that the specified keepalive packet be stopped.
*
* arg1 = slot number of the keepalive to stop.
*
* Also used internally by ConnectivityService / KeepaliveTracker, with different semantics.
*/
public static final int CMD_STOP_SOCKET_KEEPALIVE = BASE + 12;
/**
* Sent by the NetworkAgent to ConnectivityService to provide status on a socket keepalive
* request. This may either be the reply to a CMD_START_SOCKET_KEEPALIVE, or an asynchronous
* error notification.
*
* This is also sent by KeepaliveTracker to the app's {@link SocketKeepalive},
* so that the app's {@link SocketKeepalive.Callback} methods can be called.
*
* arg1 = slot number of the keepalive
* arg2 = error code
*/
public static final int EVENT_SOCKET_KEEPALIVE = BASE + 13;
// TODO: move the above 2 constants down so they are in order once merge conflicts are resolved
/**
* Sent by the KeepaliveTracker to NetworkAgent to add a packet filter.
*
* For TCP keepalive offloads, keepalive packets are sent by the firmware. However, because the
* remote site will send ACK packets in response to the keepalive packets, the firmware also
* needs to be configured to properly filter the ACKs to prevent the system from waking up.
* This does not happen with UDP, so this message is TCP-specific.
* arg1 = slot number of the keepalive to filter for.
* obj = the keepalive packet to send repeatedly.
*/
public static final int CMD_ADD_KEEPALIVE_PACKET_FILTER = BASE + 16;
/**
* Sent by the KeepaliveTracker to NetworkAgent to remove a packet filter. See
* {@link #CMD_ADD_KEEPALIVE_PACKET_FILTER}.
* arg1 = slot number of the keepalive packet filter to remove.
*/
public static final int CMD_REMOVE_KEEPALIVE_PACKET_FILTER = BASE + 17;
/**
* Sent by ConnectivityService to inform this network transport of signal strength thresholds
* that when crossed should trigger a system wakeup and a NetworkCapabilities update.
*
* obj = int[] describing signal strength thresholds.
*/
public static final int CMD_SET_SIGNAL_STRENGTH_THRESHOLDS = BASE + 14;
/**
* Sent by ConnectivityService to the NeworkAgent to inform the agent to avoid
* automatically reconnecting to this network (e.g. via autojoin). Happens
* when user selects "No" option on the "Stay connected?" dialog box.
*/
public static final int CMD_PREVENT_AUTOMATIC_RECONNECT = BASE + 15;
// TODO : remove these two constructors. They are a stopgap measure to help sheperding a number
// of dependent changes that would conflict throughout the automerger graph. Having these
// temporarily helps with the process of going through with all these dependent changes across
// the entire tree.
public NetworkAgent(Looper looper, Context context, String logTag, NetworkInfo ni,
NetworkCapabilities nc, LinkProperties lp, int score) {
this(looper, context, logTag, ni, nc, lp, score, null, NetworkFactory.SerialNumber.NONE);
}
public NetworkAgent(Looper looper, Context context, String logTag, NetworkInfo ni,
NetworkCapabilities nc, LinkProperties lp, int score, NetworkMisc misc) {
this(looper, context, logTag, ni, nc, lp, score, misc, NetworkFactory.SerialNumber.NONE);
}
public NetworkAgent(Looper looper, Context context, String logTag, NetworkInfo ni,
NetworkCapabilities nc, LinkProperties lp, int score, int factorySerialNumber) {
this(looper, context, logTag, ni, nc, lp, score, null, factorySerialNumber);
}
public NetworkAgent(Looper looper, Context context, String logTag, NetworkInfo ni,
NetworkCapabilities nc, LinkProperties lp, int score, NetworkMisc misc,
int factorySerialNumber) {
super(looper);
LOG_TAG = logTag;
mContext = context;
mFactorySerialNumber = factorySerialNumber;
if (ni == null || nc == null || lp == null) {
throw new IllegalArgumentException();
}
if (VDBG) log("Registering NetworkAgent");
ConnectivityManager cm = (ConnectivityManager)mContext.getSystemService(
Context.CONNECTIVITY_SERVICE);
netId = cm.registerNetworkAgent(new Messenger(this), new NetworkInfo(ni),
new LinkProperties(lp), new NetworkCapabilities(nc), score, misc,
factorySerialNumber);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case AsyncChannel.CMD_CHANNEL_FULL_CONNECTION: {
if (mAsyncChannel != null) {
log("Received new connection while already connected!");
} else {
if (VDBG) log("NetworkAgent fully connected");
AsyncChannel ac = new AsyncChannel();
ac.connected(null, this, msg.replyTo);
ac.replyToMessage(msg, AsyncChannel.CMD_CHANNEL_FULLY_CONNECTED,
AsyncChannel.STATUS_SUCCESSFUL);
synchronized (mPreConnectedQueue) {
mAsyncChannel = ac;
for (Message m : mPreConnectedQueue) {
ac.sendMessage(m);
}
mPreConnectedQueue.clear();
}
}
break;
}
case AsyncChannel.CMD_CHANNEL_DISCONNECT: {
if (VDBG) log("CMD_CHANNEL_DISCONNECT");
if (mAsyncChannel != null) mAsyncChannel.disconnect();
break;
}
case AsyncChannel.CMD_CHANNEL_DISCONNECTED: {
if (DBG) log("NetworkAgent channel lost");
// let the client know CS is done with us.
unwanted();
synchronized (mPreConnectedQueue) {
mAsyncChannel = null;
}
break;
}
case CMD_SUSPECT_BAD: {
log("Unhandled Message " + msg);
break;
}
case CMD_REQUEST_BANDWIDTH_UPDATE: {
long currentTimeMs = System.currentTimeMillis();
if (VDBG) {
log("CMD_REQUEST_BANDWIDTH_UPDATE request received.");
}
if (currentTimeMs >= (mLastBwRefreshTime + BW_REFRESH_MIN_WIN_MS)) {
mPollLceScheduled = false;
if (mPollLcePending.getAndSet(true) == false) {
pollLceData();
}
} else {
// deliver the request at a later time rather than discard it completely.
if (!mPollLceScheduled) {
long waitTime = mLastBwRefreshTime + BW_REFRESH_MIN_WIN_MS -
currentTimeMs + 1;
mPollLceScheduled = sendEmptyMessageDelayed(
CMD_REQUEST_BANDWIDTH_UPDATE, waitTime);
}
}
break;
}
case CMD_REPORT_NETWORK_STATUS: {
String redirectUrl = ((Bundle)msg.obj).getString(REDIRECT_URL_KEY);
if (VDBG) {
log("CMD_REPORT_NETWORK_STATUS(" +
(msg.arg1 == VALID_NETWORK ? "VALID, " : "INVALID, ") + redirectUrl);
}
networkStatus(msg.arg1, redirectUrl);
break;
}
case CMD_SAVE_ACCEPT_UNVALIDATED: {
saveAcceptUnvalidated(msg.arg1 != 0);
break;
}
case CMD_START_SOCKET_KEEPALIVE: {
startSocketKeepalive(msg);
break;
}
case CMD_STOP_SOCKET_KEEPALIVE: {
stopSocketKeepalive(msg);
break;
}
case CMD_SET_SIGNAL_STRENGTH_THRESHOLDS: {
ArrayList<Integer> thresholds =
((Bundle) msg.obj).getIntegerArrayList("thresholds");
// TODO: Change signal strength thresholds API to use an ArrayList<Integer>
// rather than convert to int[].
int[] intThresholds = new int[(thresholds != null) ? thresholds.size() : 0];
for (int i = 0; i < intThresholds.length; i++) {
intThresholds[i] = thresholds.get(i);
}
setSignalStrengthThresholds(intThresholds);
break;
}
case CMD_PREVENT_AUTOMATIC_RECONNECT: {
preventAutomaticReconnect();
break;
}
case CMD_ADD_KEEPALIVE_PACKET_FILTER: {
addKeepalivePacketFilter(msg);
break;
}
case CMD_REMOVE_KEEPALIVE_PACKET_FILTER: {
removeKeepalivePacketFilter(msg);
break;
}
}
}
private void queueOrSendMessage(int what, Object obj) {
queueOrSendMessage(what, 0, 0, obj);
}
private void queueOrSendMessage(int what, int arg1, int arg2) {
queueOrSendMessage(what, arg1, arg2, null);
}
private void queueOrSendMessage(int what, int arg1, int arg2, Object obj) {
Message msg = Message.obtain();
msg.what = what;
msg.arg1 = arg1;
msg.arg2 = arg2;
msg.obj = obj;
queueOrSendMessage(msg);
}
private void queueOrSendMessage(Message msg) {
synchronized (mPreConnectedQueue) {
if (mAsyncChannel != null) {
mAsyncChannel.sendMessage(msg);
} else {
mPreConnectedQueue.add(msg);
}
}
}
/**
* Called by the bearer code when it has new LinkProperties data.
*/
public void sendLinkProperties(LinkProperties linkProperties) {
queueOrSendMessage(EVENT_NETWORK_PROPERTIES_CHANGED, new LinkProperties(linkProperties));
}
/**
* Called by the bearer code when it has new NetworkInfo data.
*/
@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
public void sendNetworkInfo(NetworkInfo networkInfo) {
queueOrSendMessage(EVENT_NETWORK_INFO_CHANGED, new NetworkInfo(networkInfo));
}
/**
* Called by the bearer code when it has new NetworkCapabilities data.
*/
public void sendNetworkCapabilities(NetworkCapabilities networkCapabilities) {
mPollLcePending.set(false);
mLastBwRefreshTime = System.currentTimeMillis();
queueOrSendMessage(EVENT_NETWORK_CAPABILITIES_CHANGED,
new NetworkCapabilities(networkCapabilities));
}
/**
* Called by the bearer code when it has a new score for this network.
*/
public void sendNetworkScore(int score) {
if (score < 0) {
throw new IllegalArgumentException("Score must be >= 0");
}
queueOrSendMessage(EVENT_NETWORK_SCORE_CHANGED, score, 0);
}
/**
* Called by the bearer to indicate this network was manually selected by the user.
* This should be called before the NetworkInfo is marked CONNECTED so that this
* Network can be given special treatment at that time. If {@code acceptUnvalidated} is
* {@code true}, then the system will switch to this network. If it is {@code false} and the
* network cannot be validated, the system will ask the user whether to switch to this network.
* If the user confirms and selects "don't ask again", then the system will call
* {@link #saveAcceptUnvalidated} to persist the user's choice. Thus, if the transport ever
* calls this method with {@code acceptUnvalidated} set to {@code false}, it must also implement
* {@link #saveAcceptUnvalidated} to respect the user's choice.
*/
public void explicitlySelected(boolean acceptUnvalidated) {
explicitlySelected(true /* explicitlySelected */, acceptUnvalidated);
}
/**
* Called by the bearer to indicate this network was manually selected by the user.
* This should be called before the NetworkInfo is marked CONNECTED so that this
* Network can be given special treatment at that time. If {@code acceptUnvalidated} is
* {@code true}, then the system will switch to this network. If it is {@code false} and the
* network cannot be validated, the system will ask the user whether to switch to this network.
* If the user confirms and selects "don't ask again", then the system will call
* {@link #saveAcceptUnvalidated} to persist the user's choice. Thus, if the transport ever
* calls this method with {@code acceptUnvalidated} set to {@code false}, it must also implement
* {@link #saveAcceptUnvalidated} to respect the user's choice.
*/
public void explicitlySelected(boolean explicitlySelected, boolean acceptUnvalidated) {
queueOrSendMessage(EVENT_SET_EXPLICITLY_SELECTED,
explicitlySelected ? 1 : 0,
acceptUnvalidated ? 1 : 0);
}
/**
* Called when ConnectivityService has indicated they no longer want this network.
* The parent factory should (previously) have received indication of the change
* as well, either canceling NetworkRequests or altering their score such that this
* network won't be immediately requested again.
*/
abstract protected void unwanted();
/**
* Called when ConnectivityService request a bandwidth update. The parent factory
* shall try to overwrite this method and produce a bandwidth update if capable.
*/
protected void pollLceData() {
}
/**
* Called when the system determines the usefulness of this network.
*
* Networks claiming internet connectivity will have their internet
* connectivity verified.
*
* Currently there are two possible values:
* {@code VALID_NETWORK} if the system is happy with the connection,
* {@code INVALID_NETWORK} if the system is not happy.
* TODO - add indications of captive portal-ness and related success/failure,
* ie, CAPTIVE_SUCCESS_NETWORK, CAPTIVE_NETWORK for successful login and detection
*
* This may be called multiple times as the network status changes and may
* generate false negatives if we lose ip connectivity before the link is torn down.
*
* @param status one of {@code VALID_NETWORK} or {@code INVALID_NETWORK}.
* @param redirectUrl If the Internet probe was redirected, this is the destination it was
* redirected to, otherwise {@code null}.
*/
protected void networkStatus(int status, String redirectUrl) {
}
/**
* Called when the user asks to remember the choice to use this network even if unvalidated.
* The transport is responsible for remembering the choice, and the next time the user connects
* to the network, should explicitlySelected with {@code acceptUnvalidated} set to {@code true}.
* This method will only be called if {@link #explicitlySelected} was called with
* {@code acceptUnvalidated} set to {@code false}.
*/
protected void saveAcceptUnvalidated(boolean accept) {
}
/**
* Requests that the network hardware send the specified packet at the specified interval.
*/
protected void startSocketKeepalive(Message msg) {
onSocketKeepaliveEvent(msg.arg1, SocketKeepalive.ERROR_UNSUPPORTED);
}
/**
* Requests that the network hardware send the specified packet at the specified interval.
*/
protected void stopSocketKeepalive(Message msg) {
onSocketKeepaliveEvent(msg.arg1, SocketKeepalive.ERROR_UNSUPPORTED);
}
/**
* Called by the network when a socket keepalive event occurs.
*/
public void onSocketKeepaliveEvent(int slot, int reason) {
queueOrSendMessage(EVENT_SOCKET_KEEPALIVE, slot, reason);
}
/**
* Called by ConnectivityService to add specific packet filter to network hardware to block
* ACKs matching the sent keepalive packets. Implementations that support this feature must
* override this method.
*/
protected void addKeepalivePacketFilter(Message msg) {
}
/**
* Called by ConnectivityService to remove a packet filter installed with
* {@link #addKeepalivePacketFilter(Message)}. Implementations that support this feature
* must override this method.
*/
protected void removeKeepalivePacketFilter(Message msg) {
}
/**
* Called by ConnectivityService to inform this network transport of signal strength thresholds
* that when crossed should trigger a system wakeup and a NetworkCapabilities update.
*/
protected void setSignalStrengthThresholds(int[] thresholds) {
}
/**
* Called when the user asks to not stay connected to this network because it was found to not
* provide Internet access. Usually followed by call to {@code unwanted}. The transport is
* responsible for making sure the device does not automatically reconnect to the same network
* after the {@code unwanted} call.
*/
protected void preventAutomaticReconnect() {
}
protected void log(String s) {
Log.d(LOG_TAG, "NetworkAgent: " + s);
}
}