Don't crash if the PREF64 expires when IpClient is stopped.

Currently the code does not cancel the PREF64 alarm when IpClient
is stopped. If the alarm fires when IpClient has disconnected, it
will call updatePref64 with a null prefix, which will crash.

Ensure that the alarm is cancelled when IpClient is stopped.

Bug: 153694684
Bug: 155559286
Test: new unit tests
Change-Id: I397eb36c1a8ecf1324de33e720577fe2e4e07056

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/integration/src/android/net/ip/IpClientIntegrationTest.java b/tests/integration/src/android/net/ip/IpClientIntegrationTest.java
index 225f598..4a3f445 100644
--- a/tests/integration/src/android/net/ip/IpClientIntegrationTest.java
+++ b/tests/integration/src/android/net/ip/IpClientIntegrationTest.java
@@ -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 {