/*
* 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 com.android.server.connectivity;
import static android.net.CaptivePortal.APP_RETURN_DISMISSED;
import static android.net.CaptivePortal.APP_RETURN_UNWANTED;
import static android.net.CaptivePortal.APP_RETURN_WANTED_AS_IS;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.CaptivePortal;
import android.net.ConnectivityManager;
import android.net.ICaptivePortal;
import android.net.NetworkRequest;
import android.net.ProxyInfo;
import android.net.TrafficStats;
import android.net.Uri;
import android.net.metrics.IpConnectivityLog;
import android.net.metrics.NetworkEvent;
import android.net.metrics.ValidationProbeEvent;
import android.net.util.Stopwatch;
import android.net.wifi.WifiInfo;
import android.net.wifi.WifiManager;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.os.UserHandle;
import android.provider.Settings;
import android.telephony.CellIdentityCdma;
import android.telephony.CellIdentityGsm;
import android.telephony.CellIdentityLte;
import android.telephony.CellIdentityWcdma;
import android.telephony.CellInfo;
import android.telephony.CellInfoCdma;
import android.telephony.CellInfoGsm;
import android.telephony.CellInfoLte;
import android.telephony.CellInfoWcdma;
import android.telephony.TelephonyManager;
import android.text.TextUtils;
import android.util.LocalLog;
import android.util.LocalLog.ReadOnlyLocalLog;
import android.util.Log;
import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.util.Protocol;
import com.android.internal.util.State;
import com.android.internal.util.StateMachine;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.List;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
/**
* {@hide}
*/
public class NetworkMonitor extends StateMachine {
private static final String TAG = NetworkMonitor.class.getSimpleName();
private static final boolean DBG = false;
// Default configuration values for captive portal detection probes.
// TODO: append a random length parameter to the default HTTPS url.
// TODO: randomize browser version ids in the default User-Agent String.
private static final String DEFAULT_HTTPS_URL = "https://www.google.com/generate_204";
private static final String DEFAULT_HTTP_URL =
"http://connectivitycheck.gstatic.com/generate_204";
private static final String DEFAULT_FALLBACK_URL = "http://www.google.com/gen_204";
private static final String DEFAULT_USER_AGENT = "Mozilla/5.0 (X11; Linux x86_64) "
+ "AppleWebKit/537.36 (KHTML, like Gecko) "
+ "Chrome/52.0.2743.82 Safari/537.36";
private static final int SOCKET_TIMEOUT_MS = 10000;
private static final int PROBE_TIMEOUT_MS = 3000;
public static final String ACTION_NETWORK_CONDITIONS_MEASURED =
"android.net.conn.NETWORK_CONDITIONS_MEASURED";
public static final String EXTRA_CONNECTIVITY_TYPE = "extra_connectivity_type";
public static final String EXTRA_NETWORK_TYPE = "extra_network_type";
public static final String EXTRA_RESPONSE_RECEIVED = "extra_response_received";
public static final String EXTRA_IS_CAPTIVE_PORTAL = "extra_is_captive_portal";
public static final String EXTRA_CELL_ID = "extra_cellid";
public static final String EXTRA_SSID = "extra_ssid";
public static final String EXTRA_BSSID = "extra_bssid";
/** real time since boot */
public static final String EXTRA_REQUEST_TIMESTAMP_MS = "extra_request_timestamp_ms";
public static final String EXTRA_RESPONSE_TIMESTAMP_MS = "extra_response_timestamp_ms";
private static final String PERMISSION_ACCESS_NETWORK_CONDITIONS =
"android.permission.ACCESS_NETWORK_CONDITIONS";
// After a network has been tested this result can be sent with EVENT_NETWORK_TESTED.
// The network should be used as a default internet connection. It was found to be:
// 1. a functioning network providing internet access, or
// 2. a captive portal and the user decided to use it as is.
public static final int NETWORK_TEST_RESULT_VALID = 0;
// After a network has been tested this result can be sent with EVENT_NETWORK_TESTED.
// The network should not be used as a default internet connection. It was found to be:
// 1. a captive portal and the user is prompted to sign-in, or
// 2. a captive portal and the user did not want to use it, or
// 3. a broken network (e.g. DNS failed, connect failed, HTTP request failed).
public static final int NETWORK_TEST_RESULT_INVALID = 1;
private static final int BASE = Protocol.BASE_NETWORK_MONITOR;
/**
* Inform NetworkMonitor that their network is connected.
* Initiates Network Validation.
*/
public static final int CMD_NETWORK_CONNECTED = BASE + 1;
/**
* Inform ConnectivityService that the network has been tested.
* obj = String representing URL that Internet probe was redirect to, if it was redirected.
* arg1 = One of the NETWORK_TESTED_RESULT_* constants.
* arg2 = NetID.
*/
public static final int EVENT_NETWORK_TESTED = BASE + 2;
/**
* Message to self indicating it's time to evaluate a network's connectivity.
* arg1 = Token to ignore old messages.
*/
private static final int CMD_REEVALUATE = BASE + 6;
/**
* Inform NetworkMonitor that the network has disconnected.
*/
public static final int CMD_NETWORK_DISCONNECTED = BASE + 7;
/**
* Force evaluation even if it has succeeded in the past.
* arg1 = UID responsible for requesting this reeval. Will be billed for data.
*/
public static final int CMD_FORCE_REEVALUATION = BASE + 8;
/**
* Message to self indicating captive portal app finished.
* arg1 = one of: APP_RETURN_DISMISSED,
* APP_RETURN_UNWANTED,
* APP_RETURN_WANTED_AS_IS
* obj = mCaptivePortalLoggedInResponseToken as String
*/
private static final int CMD_CAPTIVE_PORTAL_APP_FINISHED = BASE + 9;
/**
* Request ConnectivityService display provisioning notification.
* arg1 = Whether to make the notification visible.
* arg2 = NetID.
* obj = Intent to be launched when notification selected by user, null if !arg1.
*/
public static final int EVENT_PROVISIONING_NOTIFICATION = BASE + 10;
/**
* Message to self indicating sign-in app should be launched.
* Sent by mLaunchCaptivePortalAppBroadcastReceiver when the
* user touches the sign in notification.
*/
private static final int CMD_LAUNCH_CAPTIVE_PORTAL_APP = BASE + 11;
/**
* Retest network to see if captive portal is still in place.
* arg1 = UID responsible for requesting this reeval. Will be billed for data.
* 0 indicates self-initiated, so nobody to blame.
*/
private static final int CMD_CAPTIVE_PORTAL_RECHECK = BASE + 12;
// Start mReevaluateDelayMs at this value and double.
private static final int INITIAL_REEVALUATE_DELAY_MS = 1000;
private static final int MAX_REEVALUATE_DELAY_MS = 10*60*1000;
// Before network has been evaluated this many times, ignore repeated reevaluate requests.
private static final int IGNORE_REEVALUATE_ATTEMPTS = 5;
private int mReevaluateToken = 0;
private static final int INVALID_UID = -1;
private int mUidResponsibleForReeval = INVALID_UID;
// Stop blaming UID that requested re-evaluation after this many attempts.
private static final int BLAME_FOR_EVALUATION_ATTEMPTS = 5;
// Delay between reevaluations once a captive portal has been found.
private static final int CAPTIVE_PORTAL_REEVALUATE_DELAY_MS = 10*60*1000;
private final Context mContext;
private final Handler mConnectivityServiceHandler;
private final NetworkAgentInfo mNetworkAgentInfo;
private final int mNetId;
private final TelephonyManager mTelephonyManager;
private final WifiManager mWifiManager;
private final AlarmManager mAlarmManager;
private final NetworkRequest mDefaultRequest;
private final IpConnectivityLog mMetricsLog;
private boolean mIsCaptivePortalCheckEnabled;
private boolean mUseHttps;
// Set if the user explicitly selected "Do not use this network" in captive portal sign-in app.
private boolean mUserDoesNotWant = false;
// Avoids surfacing "Sign in to network" notification.
private boolean mDontDisplaySigninNotification = false;
public boolean systemReady = false;
private final State mDefaultState = new DefaultState();
private final State mValidatedState = new ValidatedState();
private final State mMaybeNotifyState = new MaybeNotifyState();
private final State mEvaluatingState = new EvaluatingState();
private final State mCaptivePortalState = new CaptivePortalState();
private CustomIntentReceiver mLaunchCaptivePortalAppBroadcastReceiver = null;
private final LocalLog validationLogs = new LocalLog(20); // 20 lines
private final Stopwatch mEvaluationTimer = new Stopwatch();
// This variable is set before transitioning to the mCaptivePortalState.
private CaptivePortalProbeResult mLastPortalProbeResult = CaptivePortalProbeResult.FAILED;
public NetworkMonitor(Context context, Handler handler, NetworkAgentInfo networkAgentInfo,
NetworkRequest defaultRequest) {
this(context, handler, networkAgentInfo, defaultRequest, new IpConnectivityLog());
}
@VisibleForTesting
protected NetworkMonitor(Context context, Handler handler, NetworkAgentInfo networkAgentInfo,
NetworkRequest defaultRequest, IpConnectivityLog logger) {
// Add suffix indicating which NetworkMonitor we're talking about.
super(TAG + networkAgentInfo.name());
mContext = context;
mMetricsLog = logger;
mConnectivityServiceHandler = handler;
mNetworkAgentInfo = networkAgentInfo;
mNetId = mNetworkAgentInfo.network.netId;
mTelephonyManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
mWifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
mAlarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
mDefaultRequest = defaultRequest;
addState(mDefaultState);
addState(mValidatedState, mDefaultState);
addState(mMaybeNotifyState, mDefaultState);
addState(mEvaluatingState, mMaybeNotifyState);
addState(mCaptivePortalState, mMaybeNotifyState);
setInitialState(mDefaultState);
mIsCaptivePortalCheckEnabled = Settings.Global.getInt(mContext.getContentResolver(),
Settings.Global.CAPTIVE_PORTAL_DETECTION_ENABLED, 1) == 1;
mUseHttps = Settings.Global.getInt(mContext.getContentResolver(),
Settings.Global.CAPTIVE_PORTAL_USE_HTTPS, 1) == 1;
start();
}
@Override
protected void log(String s) {
if (DBG) Log.d(TAG + "/" + mNetworkAgentInfo.name(), s);
}
private void validationLog(String s) {
if (DBG) log(s);
validationLogs.log(s);
}
public ReadOnlyLocalLog getValidationLogs() {
return validationLogs.readOnlyLocalLog();
}
// DefaultState is the parent of all States. It exists only to handle CMD_* messages but
// does not entail any real state (hence no enter() or exit() routines).
private class DefaultState extends State {
@Override
public boolean processMessage(Message message) {
switch (message.what) {
case CMD_NETWORK_CONNECTED:
logNetworkEvent(NetworkEvent.NETWORK_CONNECTED);
transitionTo(mEvaluatingState);
return HANDLED;
case CMD_NETWORK_DISCONNECTED:
logNetworkEvent(NetworkEvent.NETWORK_DISCONNECTED);
if (mLaunchCaptivePortalAppBroadcastReceiver != null) {
mContext.unregisterReceiver(mLaunchCaptivePortalAppBroadcastReceiver);
mLaunchCaptivePortalAppBroadcastReceiver = null;
}
quit();
return HANDLED;
case CMD_FORCE_REEVALUATION:
case CMD_CAPTIVE_PORTAL_RECHECK:
log("Forcing reevaluation for UID " + message.arg1);
mUidResponsibleForReeval = message.arg1;
transitionTo(mEvaluatingState);
return HANDLED;
case CMD_CAPTIVE_PORTAL_APP_FINISHED:
log("CaptivePortal App responded with " + message.arg1);
// If the user has seen and acted on a captive portal notification, and the
// captive portal app is now closed, disable HTTPS probes. This avoids the
// following pathological situation:
//
// 1. HTTP probe returns a captive portal, HTTPS probe fails or times out.
// 2. User opens the app and logs into the captive portal.
// 3. HTTP starts working, but HTTPS still doesn't work for some other reason -
// perhaps due to the network blocking HTTPS?
//
// In this case, we'll fail to validate the network even after the app is
// dismissed. There is now no way to use this network, because the app is now
// gone, so the user cannot select "Use this network as is".
mUseHttps = false;
switch (message.arg1) {
case APP_RETURN_DISMISSED:
sendMessage(CMD_FORCE_REEVALUATION, 0 /* no UID */, 0);
break;
case APP_RETURN_WANTED_AS_IS:
mDontDisplaySigninNotification = true;
// TODO: Distinguish this from a network that actually validates.
// Displaying the "!" on the system UI icon may still be a good idea.
transitionTo(mValidatedState);
break;
case APP_RETURN_UNWANTED:
mDontDisplaySigninNotification = true;
mUserDoesNotWant = true;
mConnectivityServiceHandler.sendMessage(obtainMessage(
EVENT_NETWORK_TESTED, NETWORK_TEST_RESULT_INVALID,
mNetId, null));
// TODO: Should teardown network.
mUidResponsibleForReeval = 0;
transitionTo(mEvaluatingState);
break;
}
return HANDLED;
default:
return HANDLED;
}
}
}
// Being in the ValidatedState State indicates a Network is:
// - Successfully validated, or
// - Wanted "as is" by the user, or
// - Does not satisfy the default NetworkRequest and so validation has been skipped.
private class ValidatedState extends State {
@Override
public void enter() {
maybeLogEvaluationResult(NetworkEvent.NETWORK_VALIDATED);
mConnectivityServiceHandler.sendMessage(obtainMessage(EVENT_NETWORK_TESTED,
NETWORK_TEST_RESULT_VALID, mNetworkAgentInfo.network.netId, null));
}
@Override
public boolean processMessage(Message message) {
switch (message.what) {
case CMD_NETWORK_CONNECTED:
transitionTo(mValidatedState);
return HANDLED;
default:
return NOT_HANDLED;
}
}
}
// Being in the MaybeNotifyState State indicates the user may have been notified that sign-in
// is required. This State takes care to clear the notification upon exit from the State.
private class MaybeNotifyState extends State {
@Override
public boolean processMessage(Message message) {
switch (message.what) {
case CMD_LAUNCH_CAPTIVE_PORTAL_APP:
final Intent intent = new Intent(
ConnectivityManager.ACTION_CAPTIVE_PORTAL_SIGN_IN);
intent.putExtra(ConnectivityManager.EXTRA_NETWORK, mNetworkAgentInfo.network);
intent.putExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL,
new CaptivePortal(new ICaptivePortal.Stub() {
@Override
public void appResponse(int response) {
if (response == APP_RETURN_WANTED_AS_IS) {
mContext.enforceCallingPermission(
android.Manifest.permission.CONNECTIVITY_INTERNAL,
"CaptivePortal");
}
sendMessage(CMD_CAPTIVE_PORTAL_APP_FINISHED, response);
}
}));
intent.putExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL_URL,
mLastPortalProbeResult.detectUrl);
intent.setFlags(
Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | Intent.FLAG_ACTIVITY_NEW_TASK);
mContext.startActivityAsUser(intent, UserHandle.CURRENT);
return HANDLED;
default:
return NOT_HANDLED;
}
}
@Override
public void exit() {
Message message = obtainMessage(EVENT_PROVISIONING_NOTIFICATION, 0,
mNetworkAgentInfo.network.netId, null);
mConnectivityServiceHandler.sendMessage(message);
}
}
/**
* Result of calling isCaptivePortal().
* @hide
*/
@VisibleForTesting
public static final class CaptivePortalProbeResult {
static final CaptivePortalProbeResult FAILED = new CaptivePortalProbeResult(599);
private final int mHttpResponseCode; // HTTP response code returned from Internet probe.
final String redirectUrl; // Redirect destination returned from Internet probe.
final String detectUrl; // URL where a 204 response code indicates
// captive portal has been appeased.
public CaptivePortalProbeResult(
int httpResponseCode, String redirectUrl, String detectUrl) {
mHttpResponseCode = httpResponseCode;
this.redirectUrl = redirectUrl;
this.detectUrl = detectUrl;
}
public CaptivePortalProbeResult(int httpResponseCode) {
this(httpResponseCode, null, null);
}
boolean isSuccessful() { return mHttpResponseCode == 204; }
boolean isPortal() {
return !isSuccessful() && mHttpResponseCode >= 200 && mHttpResponseCode <= 399;
}
}
// Being in the EvaluatingState State indicates the Network is being evaluated for internet
// connectivity, or that the user has indicated that this network is unwanted.
private class EvaluatingState extends State {
private int mReevaluateDelayMs;
private int mAttempts;
@Override
public void enter() {
// If we have already started to track time spent in EvaluatingState
// don't reset the timer due simply to, say, commands or events that
// cause us to exit and re-enter EvaluatingState.
if (!mEvaluationTimer.isStarted()) {
mEvaluationTimer.start();
}
sendMessage(CMD_REEVALUATE, ++mReevaluateToken, 0);
if (mUidResponsibleForReeval != INVALID_UID) {
TrafficStats.setThreadStatsUid(mUidResponsibleForReeval);
mUidResponsibleForReeval = INVALID_UID;
}
mReevaluateDelayMs = INITIAL_REEVALUATE_DELAY_MS;
mAttempts = 0;
}
@Override
public boolean processMessage(Message message) {
switch (message.what) {
case CMD_REEVALUATE:
if (message.arg1 != mReevaluateToken || mUserDoesNotWant)
return HANDLED;
// Don't bother validating networks that don't satisify the default request.
// This includes:
// - VPNs which can be considered explicitly desired by the user and the
// user's desire trumps whether the network validates.
// - Networks that don't provide internet access. It's unclear how to
// validate such networks.
// - Untrusted networks. It's unsafe to prompt the user to sign-in to
// such networks and the user didn't express interest in connecting to
// such networks (an app did) so the user may be unhappily surprised when
// asked to sign-in to a network they didn't want to connect to in the
// first place. Validation could be done to adjust the network scores
// however these networks are app-requested and may not be intended for
// general usage, in which case general validation may not be an accurate
// measure of the network's quality. Only the app knows how to evaluate
// the network so don't bother validating here. Furthermore sending HTTP
// packets over the network may be undesirable, for example an extremely
// expensive metered network, or unwanted leaking of the User Agent string.
if (!mDefaultRequest.networkCapabilities.satisfiedByNetworkCapabilities(
mNetworkAgentInfo.networkCapabilities)) {
validationLog("Network would not satisfy default request, not validating");
transitionTo(mValidatedState);
return HANDLED;
}
mAttempts++;
// Note: This call to isCaptivePortal() could take up to a minute. Resolving the
// server's IP addresses could hit the DNS timeout, and attempting connections
// to each of the server's several IP addresses (currently one IPv4 and one
// IPv6) could each take SOCKET_TIMEOUT_MS. During this time this StateMachine
// will be unresponsive. isCaptivePortal() could be executed on another Thread
// if this is found to cause problems.
CaptivePortalProbeResult probeResult = isCaptivePortal();
if (probeResult.isSuccessful()) {
transitionTo(mValidatedState);
} else if (probeResult.isPortal()) {
mConnectivityServiceHandler.sendMessage(obtainMessage(EVENT_NETWORK_TESTED,
NETWORK_TEST_RESULT_INVALID, mNetId, probeResult.redirectUrl));
mLastPortalProbeResult = probeResult;
transitionTo(mCaptivePortalState);
} else {
final Message msg = obtainMessage(CMD_REEVALUATE, ++mReevaluateToken, 0);
sendMessageDelayed(msg, mReevaluateDelayMs);
logNetworkEvent(NetworkEvent.NETWORK_VALIDATION_FAILED);
mConnectivityServiceHandler.sendMessage(obtainMessage(
EVENT_NETWORK_TESTED, NETWORK_TEST_RESULT_INVALID, mNetId,
probeResult.redirectUrl));
if (mAttempts >= BLAME_FOR_EVALUATION_ATTEMPTS) {
// Don't continue to blame UID forever.
TrafficStats.clearThreadStatsUid();
}
mReevaluateDelayMs *= 2;
if (mReevaluateDelayMs > MAX_REEVALUATE_DELAY_MS) {
mReevaluateDelayMs = MAX_REEVALUATE_DELAY_MS;
}
}
return HANDLED;
case CMD_FORCE_REEVALUATION:
// Before IGNORE_REEVALUATE_ATTEMPTS attempts are made,
// ignore any re-evaluation requests. After, restart the
// evaluation process via EvaluatingState#enter.
return (mAttempts < IGNORE_REEVALUATE_ATTEMPTS) ? HANDLED : NOT_HANDLED;
default:
return NOT_HANDLED;
}
}
@Override
public void exit() {
TrafficStats.clearThreadStatsUid();
}
}
// BroadcastReceiver that waits for a particular Intent and then posts a message.
private class CustomIntentReceiver extends BroadcastReceiver {
private final int mToken;
private final int mWhat;
private final String mAction;
CustomIntentReceiver(String action, int token, int what) {
mToken = token;
mWhat = what;
mAction = action + "_" + mNetworkAgentInfo.network.netId + "_" + token;
mContext.registerReceiver(this, new IntentFilter(mAction));
}
public PendingIntent getPendingIntent() {
final Intent intent = new Intent(mAction);
intent.setPackage(mContext.getPackageName());
return PendingIntent.getBroadcast(mContext, 0, intent, 0);
}
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(mAction)) sendMessage(obtainMessage(mWhat, mToken));
}
}
// Being in the CaptivePortalState State indicates a captive portal was detected and the user
// has been shown a notification to sign-in.
private class CaptivePortalState extends State {
private static final String ACTION_LAUNCH_CAPTIVE_PORTAL_APP =
"android.net.netmon.launchCaptivePortalApp";
@Override
public void enter() {
maybeLogEvaluationResult(NetworkEvent.NETWORK_CAPTIVE_PORTAL_FOUND);
// Don't annoy user with sign-in notifications.
if (mDontDisplaySigninNotification) return;
// Create a CustomIntentReceiver that sends us a
// CMD_LAUNCH_CAPTIVE_PORTAL_APP message when the user
// touches the notification.
if (mLaunchCaptivePortalAppBroadcastReceiver == null) {
// Wait for result.
mLaunchCaptivePortalAppBroadcastReceiver = new CustomIntentReceiver(
ACTION_LAUNCH_CAPTIVE_PORTAL_APP, new Random().nextInt(),
CMD_LAUNCH_CAPTIVE_PORTAL_APP);
}
// Display the sign in notification.
Message message = obtainMessage(EVENT_PROVISIONING_NOTIFICATION, 1,
mNetworkAgentInfo.network.netId,
mLaunchCaptivePortalAppBroadcastReceiver.getPendingIntent());
mConnectivityServiceHandler.sendMessage(message);
// Retest for captive portal occasionally.
sendMessageDelayed(CMD_CAPTIVE_PORTAL_RECHECK, 0 /* no UID */,
CAPTIVE_PORTAL_REEVALUATE_DELAY_MS);
}
@Override
public void exit() {
removeMessages(CMD_CAPTIVE_PORTAL_RECHECK);
}
}
private static String getCaptivePortalServerHttpsUrl(Context context) {
return getSetting(context, Settings.Global.CAPTIVE_PORTAL_HTTPS_URL, DEFAULT_HTTPS_URL);
}
public static String getCaptivePortalServerHttpUrl(Context context) {
return getSetting(context, Settings.Global.CAPTIVE_PORTAL_HTTP_URL, DEFAULT_HTTP_URL);
}
private static String getCaptivePortalFallbackUrl(Context context) {
return getSetting(context,
Settings.Global.CAPTIVE_PORTAL_FALLBACK_URL, DEFAULT_FALLBACK_URL);
}
private static String getCaptivePortalUserAgent(Context context) {
return getSetting(context, Settings.Global.CAPTIVE_PORTAL_USER_AGENT, DEFAULT_USER_AGENT);
}
private static String getSetting(Context context, String symbol, String defaultValue) {
final String value = Settings.Global.getString(context.getContentResolver(), symbol);
return value != null ? value : defaultValue;
}
@VisibleForTesting
protected CaptivePortalProbeResult isCaptivePortal() {
if (!mIsCaptivePortalCheckEnabled) return new CaptivePortalProbeResult(204);
URL pacUrl = null, httpsUrl = null, httpUrl = null, fallbackUrl = null;
// On networks with a PAC instead of fetching a URL that should result in a 204
// response, we instead simply fetch the PAC script. This is done for a few reasons:
// 1. At present our PAC code does not yet handle multiple PACs on multiple networks
// until something like https://android-review.googlesource.com/#/c/115180/ lands.
// Network.openConnection() will ignore network-specific PACs and instead fetch
// using NO_PROXY. If a PAC is in place, the only fetch we know will succeed with
// NO_PROXY is the fetch of the PAC itself.
// 2. To proxy the generate_204 fetch through a PAC would require a number of things
// happen before the fetch can commence, namely:
// a) the PAC script be fetched
// b) a PAC script resolver service be fired up and resolve the captive portal
// server.
// Network validation could be delayed until these prerequisities are satisifed or
// could simply be left to race them. Neither is an optimal solution.
// 3. PAC scripts are sometimes used to block or restrict Internet access and may in
// fact block fetching of the generate_204 URL which would lead to false negative
// results for network validation.
final ProxyInfo proxyInfo = mNetworkAgentInfo.linkProperties.getHttpProxy();
if (proxyInfo != null && !Uri.EMPTY.equals(proxyInfo.getPacFileUrl())) {
pacUrl = makeURL(proxyInfo.getPacFileUrl().toString());
if (pacUrl == null) {
return CaptivePortalProbeResult.FAILED;
}
}
if (pacUrl == null) {
httpsUrl = makeURL(getCaptivePortalServerHttpsUrl(mContext));
httpUrl = makeURL(getCaptivePortalServerHttpUrl(mContext));
fallbackUrl = makeURL(getCaptivePortalFallbackUrl(mContext));
if (httpUrl == null || httpsUrl == null) {
return CaptivePortalProbeResult.FAILED;
}
}
long startTime = SystemClock.elapsedRealtime();
// Pre-resolve the captive portal server host so we can log it.
// Only do this if HttpURLConnection is about to, to avoid any potentially
// unnecessary resolution.
String hostToResolve = null;
if (pacUrl != null) {
hostToResolve = pacUrl.getHost();
} else if (proxyInfo != null) {
hostToResolve = proxyInfo.getHost();
} else {
hostToResolve = httpUrl.getHost();
}
if (!TextUtils.isEmpty(hostToResolve)) {
String probeName = ValidationProbeEvent.getProbeName(ValidationProbeEvent.PROBE_DNS);
final Stopwatch dnsTimer = new Stopwatch().start();
int dnsResult;
long dnsLatency;
try {
InetAddress[] addresses = mNetworkAgentInfo.network.getAllByName(hostToResolve);
dnsResult = ValidationProbeEvent.DNS_SUCCESS;
dnsLatency = dnsTimer.stop();
final StringBuffer connectInfo = new StringBuffer(", " + hostToResolve + "=");
for (InetAddress address : addresses) {
connectInfo.append(address.getHostAddress());
if (address != addresses[addresses.length-1]) connectInfo.append(",");
}
validationLog(probeName + " OK " + dnsLatency + "ms" + connectInfo);
} catch (UnknownHostException e) {
dnsResult = ValidationProbeEvent.DNS_FAILURE;
dnsLatency = dnsTimer.stop();
validationLog(probeName + " FAIL " + dnsLatency + "ms, " + hostToResolve);
}
logValidationProbe(dnsLatency, ValidationProbeEvent.PROBE_DNS, dnsResult);
}
CaptivePortalProbeResult result;
if (pacUrl != null) {
result = sendHttpProbe(pacUrl, ValidationProbeEvent.PROBE_PAC);
} else if (mUseHttps) {
result = sendParallelHttpProbes(httpsUrl, httpUrl, fallbackUrl);
} else {
result = sendHttpProbe(httpUrl, ValidationProbeEvent.PROBE_HTTP);
}
long endTime = SystemClock.elapsedRealtime();
sendNetworkConditionsBroadcast(true /* response received */,
result.isPortal() /* isCaptivePortal */,
startTime, endTime);
return result;
}
/**
* Do a URL fetch on a known server to see if we get the data we expect.
* Returns HTTP response code.
*/
@VisibleForTesting
protected CaptivePortalProbeResult sendHttpProbe(URL url, int probeType) {
HttpURLConnection urlConnection = null;
int httpResponseCode = 599;
String redirectUrl = null;
final Stopwatch probeTimer = new Stopwatch().start();
try {
urlConnection = (HttpURLConnection) mNetworkAgentInfo.network.openConnection(url);
urlConnection.setInstanceFollowRedirects(probeType == ValidationProbeEvent.PROBE_PAC);
urlConnection.setConnectTimeout(SOCKET_TIMEOUT_MS);
urlConnection.setReadTimeout(SOCKET_TIMEOUT_MS);
urlConnection.setUseCaches(false);
final String userAgent = getCaptivePortalUserAgent(mContext);
if (userAgent != null) {
urlConnection.setRequestProperty("User-Agent", userAgent);
}
// Time how long it takes to get a response to our request
long requestTimestamp = SystemClock.elapsedRealtime();
httpResponseCode = urlConnection.getResponseCode();
redirectUrl = urlConnection.getHeaderField("location");
// Time how long it takes to get a response to our request
long responseTimestamp = SystemClock.elapsedRealtime();
validationLog(ValidationProbeEvent.getProbeName(probeType) + " " + url +
" time=" + (responseTimestamp - requestTimestamp) + "ms" +
" ret=" + httpResponseCode +
" headers=" + urlConnection.getHeaderFields());
// NOTE: We may want to consider an "HTTP/1.0 204" response to be a captive
// portal. The only example of this seen so far was a captive portal. For
// the time being go with prior behavior of assuming it's not a captive
// portal. If it is considered a captive portal, a different sign-in URL
// is needed (i.e. can't browse a 204). This could be the result of an HTTP
// proxy server.
// Consider 200 response with "Content-length=0" to not be a captive portal.
// There's no point in considering this a captive portal as the user cannot
// sign-in to an empty page. Probably the result of a broken transparent proxy.
// See http://b/9972012.
if (httpResponseCode == 200 && urlConnection.getContentLength() == 0) {
validationLog("Empty 200 response interpreted as 204 response.");
httpResponseCode = 204;
}
if (httpResponseCode == 200 && probeType == ValidationProbeEvent.PROBE_PAC) {
validationLog("PAC fetch 200 response interpreted as 204 response.");
httpResponseCode = 204;
}
} catch (IOException e) {
validationLog("Probably not a portal: exception " + e);
if (httpResponseCode == 599) {
// TODO: Ping gateway and DNS server and log results.
}
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
}
logValidationProbe(probeTimer.stop(), probeType, httpResponseCode);
return new CaptivePortalProbeResult(httpResponseCode, redirectUrl, url.toString());
}
private CaptivePortalProbeResult sendParallelHttpProbes(
URL httpsUrl, URL httpUrl, URL fallbackUrl) {
// Number of probes to wait for. If a probe completes with a conclusive answer
// it shortcuts the latch immediately by forcing the count to 0.
final CountDownLatch latch = new CountDownLatch(2);
final class ProbeThread extends Thread {
private final boolean mIsHttps;
private volatile CaptivePortalProbeResult mResult = CaptivePortalProbeResult.FAILED;
public ProbeThread(boolean isHttps) {
mIsHttps = isHttps;
}
public CaptivePortalProbeResult result() {
return mResult;
}
@Override
public void run() {
if (mIsHttps) {
mResult = sendHttpProbe(httpsUrl, ValidationProbeEvent.PROBE_HTTPS);
} else {
mResult = sendHttpProbe(httpUrl, ValidationProbeEvent.PROBE_HTTP);
}
if ((mIsHttps && mResult.isSuccessful()) || (!mIsHttps && mResult.isPortal())) {
// Stop waiting immediately if https succeeds or if http finds a portal.
while (latch.getCount() > 0) {
latch.countDown();
}
}
// Signal this probe has completed.
latch.countDown();
}
}
final ProbeThread httpsProbe = new ProbeThread(true);
final ProbeThread httpProbe = new ProbeThread(false);
try {
httpsProbe.start();
httpProbe.start();
latch.await(PROBE_TIMEOUT_MS, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
validationLog("Error: probes wait interrupted!");
return CaptivePortalProbeResult.FAILED;
}
final CaptivePortalProbeResult httpsResult = httpsProbe.result();
final CaptivePortalProbeResult httpResult = httpProbe.result();
// Look for a conclusive probe result first.
if (httpResult.isPortal()) {
return httpResult;
}
// httpsResult.isPortal() is not expected, but check it nonetheless.
if (httpsResult.isPortal() || httpsResult.isSuccessful()) {
return httpsResult;
}
// If a fallback url is specified, use a fallback probe to try again portal detection.
if (fallbackUrl != null) {
CaptivePortalProbeResult result =
sendHttpProbe(fallbackUrl, ValidationProbeEvent.PROBE_FALLBACK);
if (result.isPortal()) {
return result;
}
}
// Otherwise wait until https probe completes and use its result.
try {
httpsProbe.join();
} catch (InterruptedException e) {
validationLog("Error: https probe wait interrupted!");
return CaptivePortalProbeResult.FAILED;
}
return httpsProbe.result();
}
private URL makeURL(String url) {
if (url != null) {
try {
return new URL(url);
} catch (MalformedURLException e) {
validationLog("Bad URL: " + url);
}
}
return null;
}
/**
* @param responseReceived - whether or not we received a valid HTTP response to our request.
* If false, isCaptivePortal and responseTimestampMs are ignored
* TODO: This should be moved to the transports. The latency could be passed to the transports
* along with the captive portal result. Currently the TYPE_MOBILE broadcasts appear unused so
* perhaps this could just be added to the WiFi transport only.
*/
private void sendNetworkConditionsBroadcast(boolean responseReceived, boolean isCaptivePortal,
long requestTimestampMs, long responseTimestampMs) {
if (Settings.Global.getInt(mContext.getContentResolver(),
Settings.Global.WIFI_SCAN_ALWAYS_AVAILABLE, 0) == 0) {
return;
}
if (systemReady == false) return;
Intent latencyBroadcast = new Intent(ACTION_NETWORK_CONDITIONS_MEASURED);
switch (mNetworkAgentInfo.networkInfo.getType()) {
case ConnectivityManager.TYPE_WIFI:
WifiInfo currentWifiInfo = mWifiManager.getConnectionInfo();
if (currentWifiInfo != null) {
// NOTE: getSSID()'s behavior changed in API 17; before that, SSIDs were not
// surrounded by double quotation marks (thus violating the Javadoc), but this
// was changed to match the Javadoc in API 17. Since clients may have started
// sanitizing the output of this method since API 17 was released, we should
// not change it here as it would become impossible to tell whether the SSID is
// simply being surrounded by quotes due to the API, or whether those quotes
// are actually part of the SSID.
latencyBroadcast.putExtra(EXTRA_SSID, currentWifiInfo.getSSID());
latencyBroadcast.putExtra(EXTRA_BSSID, currentWifiInfo.getBSSID());
} else {
if (DBG) logw("network info is TYPE_WIFI but no ConnectionInfo found");
return;
}
break;
case ConnectivityManager.TYPE_MOBILE:
latencyBroadcast.putExtra(EXTRA_NETWORK_TYPE, mTelephonyManager.getNetworkType());
List<CellInfo> info = mTelephonyManager.getAllCellInfo();
if (info == null) return;
int numRegisteredCellInfo = 0;
for (CellInfo cellInfo : info) {
if (cellInfo.isRegistered()) {
numRegisteredCellInfo++;
if (numRegisteredCellInfo > 1) {
log("more than one registered CellInfo. Can't " +
"tell which is active. Bailing.");
return;
}
if (cellInfo instanceof CellInfoCdma) {
CellIdentityCdma cellId = ((CellInfoCdma) cellInfo).getCellIdentity();
latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
} else if (cellInfo instanceof CellInfoGsm) {
CellIdentityGsm cellId = ((CellInfoGsm) cellInfo).getCellIdentity();
latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
} else if (cellInfo instanceof CellInfoLte) {
CellIdentityLte cellId = ((CellInfoLte) cellInfo).getCellIdentity();
latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
} else if (cellInfo instanceof CellInfoWcdma) {
CellIdentityWcdma cellId = ((CellInfoWcdma) cellInfo).getCellIdentity();
latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
} else {
if (DBG) logw("Registered cellinfo is unrecognized");
return;
}
}
}
break;
default:
return;
}
latencyBroadcast.putExtra(EXTRA_CONNECTIVITY_TYPE, mNetworkAgentInfo.networkInfo.getType());
latencyBroadcast.putExtra(EXTRA_RESPONSE_RECEIVED, responseReceived);
latencyBroadcast.putExtra(EXTRA_REQUEST_TIMESTAMP_MS, requestTimestampMs);
if (responseReceived) {
latencyBroadcast.putExtra(EXTRA_IS_CAPTIVE_PORTAL, isCaptivePortal);
latencyBroadcast.putExtra(EXTRA_RESPONSE_TIMESTAMP_MS, responseTimestampMs);
}
mContext.sendBroadcastAsUser(latencyBroadcast, UserHandle.CURRENT,
PERMISSION_ACCESS_NETWORK_CONDITIONS);
}
private void logNetworkEvent(int evtype) {
mMetricsLog.log(new NetworkEvent(mNetId, evtype));
}
private void maybeLogEvaluationResult(int evtype) {
if (mEvaluationTimer.isRunning()) {
mMetricsLog.log(new NetworkEvent(mNetId, evtype, mEvaluationTimer.stop()));
mEvaluationTimer.reset();
}
}
private void logValidationProbe(long durationMs, int probeType, int probeResult) {
mMetricsLog.log(new ValidationProbeEvent(mNetId, durationMs, probeType, probeResult));
}
}