Captive portal: rotate fallback urls
This patch introduces a new settings value to specify more than one url
for the fallback http probe in addition to the existing settings value.
If more than one url exists, a network will rotate urls for the fallback
probe one by one everytime the fallback probe is sent.
(not like commit 0908daaaf00e6b56ebed0a0fce9c3e3fe183a06b, this patch
uses a comma to separate fallback urls, which works as expected with
Java's String.split())
Test: built, flashed, tested manually with various portal networks.
Bug: 36532213
Change-Id: I3c010bfee5b99db03a500776fbf47959a29d0578
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 8e55f4b..3f3f859 100755
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -8183,6 +8183,15 @@
public static final String CAPTIVE_PORTAL_FALLBACK_URL = "captive_portal_fallback_url";
/**
+ * A comma separated list of URLs used for captive portal detection in addition to the
+ * fallback HTTP url associated with the CAPTIVE_PORTAL_FALLBACK_URL settings.
+ *
+ * @hide
+ */
+ public static final String CAPTIVE_PORTAL_OTHER_FALLBACK_URLS =
+ "captive_portal_other_fallback_urls";
+
+ /**
* Whether to use HTTPS for network validation. This is enabled by default and the setting
* needs to be set to 0 to disable it. This setting is a misnomer because captive portals
* don't actually use HTTPS, but it's consistent with the other settings.
diff --git a/services/core/java/com/android/server/connectivity/NetworkMonitor.java b/services/core/java/com/android/server/connectivity/NetworkMonitor.java
index fa6f8c6..4dcf425 100644
--- a/services/core/java/com/android/server/connectivity/NetworkMonitor.java
+++ b/services/core/java/com/android/server/connectivity/NetworkMonitor.java
@@ -70,6 +70,7 @@
import java.net.MalformedURLException;
import java.net.URL;
import java.net.UnknownHostException;
+import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
@@ -90,6 +91,8 @@
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_OTHER_FALLBACK_URLS =
+ "http://play.googleapis.com/generate_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";
@@ -263,7 +266,8 @@
private final String mCaptivePortalUserAgent;
private final URL mCaptivePortalHttpsUrl;
private final URL mCaptivePortalHttpUrl;
- private final URL mCaptivePortalFallbackUrl;
+ private final URL[] mCaptivePortalFallbackUrls;
+ private int mNextFallbackUrlIndex = 0;
public NetworkMonitor(Context context, Handler handler, NetworkAgentInfo networkAgentInfo,
NetworkRequest defaultRequest) {
@@ -302,7 +306,7 @@
mCaptivePortalUserAgent = getCaptivePortalUserAgent(context);
mCaptivePortalHttpsUrl = makeURL(getCaptivePortalServerHttpsUrl(context));
mCaptivePortalHttpUrl = makeURL(getCaptivePortalServerHttpUrl(context));
- mCaptivePortalFallbackUrl = makeURL(getCaptivePortalFallbackUrl(context));
+ mCaptivePortalFallbackUrls = makeCaptivePortalFallbackUrls(context);
start();
}
@@ -450,7 +454,7 @@
intent.putExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL_URL,
mLastPortalProbeResult.detectUrl);
intent.putExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL_USER_AGENT,
- getCaptivePortalUserAgent(mContext));
+ mCaptivePortalUserAgent);
intent.setFlags(
Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | Intent.FLAG_ACTIVITY_NEW_TASK);
mContext.startActivityAsUser(intent, UserHandle.CURRENT);
@@ -677,9 +681,24 @@
return getSetting(context, Settings.Global.CAPTIVE_PORTAL_HTTP_URL, DEFAULT_HTTP_URL);
}
- private static String getCaptivePortalFallbackUrl(Context context) {
- return getSetting(context,
+ private URL[] makeCaptivePortalFallbackUrls(Context context) {
+ String separator = ",";
+ String firstUrl = getSetting(context,
Settings.Global.CAPTIVE_PORTAL_FALLBACK_URL, DEFAULT_FALLBACK_URL);
+ String joinedUrls = firstUrl + separator + getSetting(context,
+ Settings.Global.CAPTIVE_PORTAL_OTHER_FALLBACK_URLS, DEFAULT_OTHER_FALLBACK_URLS);
+ List<URL> urls = new ArrayList<>();
+ for (String s : joinedUrls.split(separator)) {
+ URL u = makeURL(s);
+ if (u == null) {
+ continue;
+ }
+ urls.add(u);
+ }
+ if (urls.isEmpty()) {
+ Log.e(TAG, String.format("could not create any url from %s", joinedUrls));
+ }
+ return urls.toArray(new URL[urls.size()]);
}
private static String getCaptivePortalUserAgent(Context context) {
@@ -691,6 +710,15 @@
return value != null ? value : defaultValue;
}
+ private URL nextFallbackUrl() {
+ if (mCaptivePortalFallbackUrls.length == 0) {
+ return null;
+ }
+ int idx = Math.abs(mNextFallbackUrlIndex) % mCaptivePortalFallbackUrls.length;
+ mNextFallbackUrlIndex += new Random().nextInt(); // randomely change url without memory.
+ return mCaptivePortalFallbackUrls[idx];
+ }
+
@VisibleForTesting
protected CaptivePortalProbeResult isCaptivePortal() {
if (!mIsCaptivePortalCheckEnabled) {
@@ -701,7 +729,6 @@
URL pacUrl = null;
URL httpsUrl = mCaptivePortalHttpsUrl;
URL httpUrl = mCaptivePortalHttpUrl;
- URL fallbackUrl = mCaptivePortalFallbackUrl;
// 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:
@@ -738,7 +765,7 @@
if (pacUrl != null) {
result = sendDnsAndHttpProbes(null, pacUrl, ValidationProbeEvent.PROBE_PAC);
} else if (mUseHttps) {
- result = sendParallelHttpProbes(proxyInfo, httpsUrl, httpUrl, fallbackUrl);
+ result = sendParallelHttpProbes(proxyInfo, httpsUrl, httpUrl);
} else {
result = sendDnsAndHttpProbes(proxyInfo, httpUrl, ValidationProbeEvent.PROBE_HTTP);
}
@@ -872,7 +899,7 @@
}
private CaptivePortalProbeResult sendParallelHttpProbes(
- ProxyInfo proxy, URL httpsUrl, URL httpUrl, URL fallbackUrl) {
+ ProxyInfo proxy, URL httpsUrl, URL httpUrl) {
// 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);
@@ -931,7 +958,8 @@
if (httpsResult.isPortal() || httpsResult.isSuccessful()) {
return httpsResult;
}
- // If a fallback url is specified, use a fallback probe to try again portal detection.
+ // If a fallback url exists, use a fallback probe to try again portal detection.
+ URL fallbackUrl = nextFallbackUrl();
if (fallbackUrl != null) {
CaptivePortalProbeResult result =
sendHttpProbe(fallbackUrl, ValidationProbeEvent.PROBE_FALLBACK);