Make NetworkMonitor do exponential backoff between reevaluation attempts.
bug:19648073
Change-Id: Idbef196710f2851c4d9d39f5776dd80a2c150ddd
diff --git a/services/core/java/com/android/server/connectivity/NetworkMonitor.java b/services/core/java/com/android/server/connectivity/NetworkMonitor.java
index 4e83992..7135f35 100644
--- a/services/core/java/com/android/server/connectivity/NetworkMonitor.java
+++ b/services/core/java/com/android/server/connectivity/NetworkMonitor.java
@@ -149,7 +149,6 @@
/**
* Force evaluation even if it has succeeded in the past.
* arg1 = UID responsible for requesting this reeval. Will be billed for data.
- * arg2 = Number of evaluation attempts to make. (If 0, make INITIAL_ATTEMPTS attempts.)
*/
public static final int CMD_FORCE_REEVALUATION = BASE + 8;
@@ -183,20 +182,18 @@
private final int mLingerDelayMs;
private int mLingerToken = 0;
- // Negative values disable reevaluation.
- private static final String REEVALUATE_DELAY_PROPERTY = "persist.netmon.reeval_delay";
- // When connecting, attempt to validate 3 times, pausing 5s between them.
- private static final int DEFAULT_REEVALUATE_DELAY_MS = 5000;
- private static final int INITIAL_ATTEMPTS = 3;
- // If a network is not validated, make one attempt every 10 mins to see if it starts working.
- private static final int REEVALUATE_PAUSE_MS = 10*60*1000;
- private static final int PERIODIC_ATTEMPTS = 1;
- // When an application calls reportNetworkConnectivity, only make one attempt.
- private static final int REEVALUATE_ATTEMPTS = 1;
- private final int mReevaluateDelayMs;
+ // 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;
+ // When network has been evaluated this many times:
+ // 1. report NETWORK_TEST_RESULT_INVALID
+ // 2. stop blaming UID that requested re-evaluation for further attempts
+ private static final int INITIAL_EVALUATION_ATTEMPTS = 3;
private final Context mContext;
private final Handler mConnectivityServiceHandler;
@@ -212,18 +209,9 @@
// Set if the user explicitly selected "Do not use this network" in captive portal sign-in app.
private boolean mUserDoesNotWant = false;
- // How many times we should attempt validation. Only checked in EvaluatingState; must be set
- // before entering EvaluatingState. Note that whatever code causes us to transition to
- // EvaluatingState last decides how many attempts will be made, so if one codepath were to
- // enter EvaluatingState with a specific number of attempts, and then another were to enter it
- // with a different number of attempts, the second number would be used. This is not currently
- // a problem because EvaluatingState is not reentrant.
- private int mMaxAttempts;
-
public boolean systemReady = false;
private final State mDefaultState = new DefaultState();
- private final State mOfflineState = new OfflineState();
private final State mValidatedState = new ValidatedState();
private final State mMaybeNotifyState = new MaybeNotifyState();
private final State mEvaluatingState = new EvaluatingState();
@@ -247,7 +235,6 @@
mDefaultRequest = defaultRequest;
addState(mDefaultState);
- addState(mOfflineState, mDefaultState);
addState(mValidatedState, mDefaultState);
addState(mMaybeNotifyState, mDefaultState);
addState(mEvaluatingState, mMaybeNotifyState);
@@ -260,8 +247,6 @@
if (mServer == null) mServer = DEFAULT_SERVER;
mLingerDelayMs = SystemProperties.getInt(LINGER_DELAY_PROPERTY, DEFAULT_LINGER_DELAY_MS);
- mReevaluateDelayMs = SystemProperties.getInt(REEVALUATE_DELAY_PROPERTY,
- DEFAULT_REEVALUATE_DELAY_MS);
mIsCaptivePortalCheckEnabled = Settings.Global.getInt(mContext.getContentResolver(),
Settings.Global.CAPTIVE_PORTAL_DETECTION_ENABLED, 1) == 1;
@@ -289,7 +274,6 @@
return HANDLED;
case CMD_NETWORK_CONNECTED:
if (DBG) log("Connected");
- mMaxAttempts = INITIAL_ATTEMPTS;
transitionTo(mEvaluatingState);
return HANDLED;
case CMD_NETWORK_DISCONNECTED:
@@ -303,7 +287,6 @@
case CMD_FORCE_REEVALUATION:
if (DBG) log("Forcing reevaluation");
mUidResponsibleForReeval = message.arg1;
- mMaxAttempts = message.arg2 != 0 ? message.arg2 : REEVALUATE_ATTEMPTS;
transitionTo(mEvaluatingState);
return HANDLED;
case CMD_CAPTIVE_PORTAL_APP_FINISHED:
@@ -313,8 +296,7 @@
mCaptivePortalLoggedInResponseToken = String.valueOf(new Random().nextLong());
switch (message.arg1) {
case ConnectivityManager.CAPTIVE_PORTAL_APP_RETURN_DISMISSED:
- sendMessage(CMD_FORCE_REEVALUATION, 0 /* no UID */,
- 0 /* INITIAL_ATTEMPTS */);
+ sendMessage(CMD_FORCE_REEVALUATION, 0 /* no UID */, 0);
break;
case ConnectivityManager.CAPTIVE_PORTAL_APP_RETURN_WANTED_AS_IS:
// TODO: Distinguish this from a network that actually validates.
@@ -323,8 +305,12 @@
break;
case ConnectivityManager.CAPTIVE_PORTAL_APP_RETURN_UNWANTED:
mUserDoesNotWant = true;
+ mConnectivityServiceHandler.sendMessage(obtainMessage(
+ EVENT_NETWORK_TESTED, NETWORK_TEST_RESULT_INVALID, 0,
+ mNetworkAgentInfo));
// TODO: Should teardown network.
- transitionTo(mOfflineState);
+ mUidResponsibleForReeval = 0;
+ transitionTo(mEvaluatingState);
break;
}
return HANDLED;
@@ -334,42 +320,6 @@
}
}
- // Being in the OfflineState State indicates a Network is unwanted or failed validation.
- private class OfflineState extends State {
- @Override
- public void enter() {
- mConnectivityServiceHandler.sendMessage(obtainMessage(EVENT_NETWORK_TESTED,
- NETWORK_TEST_RESULT_INVALID, 0, mNetworkAgentInfo));
- if (!mUserDoesNotWant) {
- sendMessageDelayed(CMD_FORCE_REEVALUATION, 0 /* no UID */,
- PERIODIC_ATTEMPTS, REEVALUATE_PAUSE_MS);
- }
- }
-
- @Override
- public boolean processMessage(Message message) {
- if (DBG) log(getName() + message.toString());
- switch (message.what) {
- case CMD_FORCE_REEVALUATION:
- // If the user has indicated they explicitly do not want to use this network,
- // don't allow a reevaluation as this will be pointless and could result in
- // the user being annoyed with repeated unwanted notifications.
- return mUserDoesNotWant ? HANDLED : NOT_HANDLED;
- default:
- return NOT_HANDLED;
- }
- }
-
- @Override
- public void exit() {
- // NOTE: This removes the delayed message posted by enter() but will inadvertently
- // remove any other CMD_FORCE_REEVALUATION in the message queue. At the moment this
- // is harmless. If in the future this becomes problematic a different message could
- // be used.
- removeMessages(CMD_FORCE_REEVALUATION);
- }
- }
-
// Being in the ValidatedState State indicates a Network is:
// - Successfully validated, or
// - Wanted "as is" by the user, or
@@ -426,18 +376,20 @@
}
// Being in the EvaluatingState State indicates the Network is being evaluated for internet
- // connectivity.
+ // connectivity, or that the user has indicated that this network is unwanted.
private class EvaluatingState extends State {
- private int mAttempt;
+ private int mReevaluateDelayMs;
+ private int mAttempts;
@Override
public void enter() {
- mAttempt = 1;
sendMessage(CMD_REEVALUATE, ++mReevaluateToken, 0);
if (mUidResponsibleForReeval != INVALID_UID) {
TrafficStats.setThreadStatsUid(mUidResponsibleForReeval);
mUidResponsibleForReeval = INVALID_UID;
}
+ mReevaluateDelayMs = INITIAL_REEVALUATE_DELAY_MS;
+ mAttempts = 0;
}
@Override
@@ -445,7 +397,7 @@
if (DBG) log(getName() + message.toString());
switch (message.what) {
case CMD_REEVALUATE:
- if (message.arg1 != mReevaluateToken)
+ if (message.arg1 != mReevaluateToken || mUserDoesNotWant)
return HANDLED;
// Don't bother validating networks that don't satisify the default request.
// This includes:
@@ -469,6 +421,7 @@
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
@@ -480,16 +433,27 @@
transitionTo(mValidatedState);
} else if (httpResponseCode >= 200 && httpResponseCode <= 399) {
transitionTo(mCaptivePortalState);
- } else if (++mAttempt > mMaxAttempts) {
- transitionTo(mOfflineState);
- } else if (mReevaluateDelayMs >= 0) {
+ } else {
Message msg = obtainMessage(CMD_REEVALUATE, ++mReevaluateToken, 0);
sendMessageDelayed(msg, mReevaluateDelayMs);
+ if (mAttempts >= INITIAL_EVALUATION_ATTEMPTS) {
+ mConnectivityServiceHandler.sendMessage(obtainMessage(
+ EVENT_NETWORK_TESTED, NETWORK_TEST_RESULT_INVALID, 0,
+ mNetworkAgentInfo));
+ // 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:
- // Ignore duplicate requests.
- return HANDLED;
+ // 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;
}
@@ -533,6 +497,8 @@
public void enter() {
mConnectivityServiceHandler.sendMessage(obtainMessage(EVENT_NETWORK_TESTED,
NETWORK_TEST_RESULT_INVALID, 0, mNetworkAgentInfo));
+ // Don't annoy user with sign-in notifications.
+ if (mUserDoesNotWant) return;
// Create a CustomIntentReceiver that sends us a
// CMD_LAUNCH_CAPTIVE_PORTAL_APP message when the user
// touches the notification.