Don't crash if the PREF64 expires when IpClient is stopped. am: cf37ca43cb (b451c135) · Commits · e / os / android_packages_modules_NetworkStack

src/android/net/ip/IpClientLinkObserver.java

+13 −4

Original line number	Diff line number	Diff line
		@@ -238,6 +238,7 @@ public class IpClientLinkObserver implements NetworkObserver {
		// while interfaceDnsServerInfo() is being called, we'll end up with no DNS servers in
		// mLinkProperties, as desired.
		mDnsServerRepository = new DnsServerRepository(mConfig.minRdnssLifetime);
		mNetlinkMonitor.clearAlarms();
		mLinkProperties.clear();
		mLinkProperties.setInterfaceName(mInterfaceName);
		}
		@@ -281,18 +282,27 @@ public class IpClientLinkObserver implements NetworkObserver {
		mIfindex = ifindex;
		}

		void clearAlarms() {
		cancelPref64Alarm();
		}

		private final AlarmManager.OnAlarmListener mExpirePref64Alarm = () -> {
		// Ignore the alarm if cancelPref64Alarm has already been called.
		//
		// TODO: in the rare case where the alarm fires and posts the lambda to the handler
		// thread while we are processing an RA that changes the lifetime of the same prefix,
		// this code will run anyway even if the alarm is rescheduled or cancelled. If the
		// lifetime in the RA is zero this doesn't matter (we just harmlessly cancel the alarm
		// one extra time) but if the lifetime is nonzero then the prefix will be added and
		// immediately removed by this code.
		// lifetime in the RA is zero this code will correctly do nothing, but if the lifetime
		// is nonzero then the prefix will be added and immediately removed by this code.
		if (mNat64PrefixExpiry == 0) return;
		updatePref64(mShim.getNat64Prefix(mLinkProperties),
		mNat64PrefixExpiry, mNat64PrefixExpiry);
		};

		private void cancelPref64Alarm() {
		// Clear the expiry in case the alarm just fired and has not been processed yet.
		if (mNat64PrefixExpiry == 0) return;
		mNat64PrefixExpiry = 0;
		mAlarmManager.cancel(mExpirePref64Alarm);
		}

		@@ -342,7 +352,6 @@ public class IpClientLinkObserver implements NetworkObserver {
		schedulePref64Alarm();
		} else {
		mShim.setNat64Prefix(mLinkProperties, null);
		mNat64PrefixExpiry = 0;
		cancelPref64Alarm();
		}

tests/integration/src/android/net/ip/IpClientIntegrationTest.java

+19 −0

Original line number	Diff line number	Diff line
		@@ -1527,6 +1527,25 @@ public class IpClientIntegrationTest {
		mIpc.getHandler().post(() -> lastAlarm.onAlarm());
		expectAlarmCancelled(inOrder, pref64Alarm);
		expectNat64PrefixUpdate(inOrder, null);

		// Re-announce the prefix.
		pref64 = new StructNdOptPref64(prefix, 600).toByteBuffer();
		ra = buildRaPacket(pio, rdnss, pref64);
		mPacketReader.sendResponse(ra);
		final OnAlarmListener clearAlarm = expectAlarmSet(inOrder, "PREF64", 600);
		expectNat64PrefixUpdate(inOrder, prefix);
		reset(mCb, mAlarm);

		// Check that the alarm is cancelled when IpClient is stopped.
		mIpc.stop();
		HandlerUtilsKt.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
		expectAlarmCancelled(inOrder, clearAlarm);
		expectNat64PrefixUpdate(inOrder, null);

		// Check that even if the alarm was already in the message queue while it was cancelled, it
		// is safely ignored.
		mIpc.getHandler().post(() -> clearAlarm.onAlarm());
		HandlerUtilsKt.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
		}

		private void addIpAddressAndWaitForIt(final String iface) throws Exception {