diff options
| -rw-r--r-- | src/android/net/ip/IpClientLinkObserver.java | 12 | ||||
| -rw-r--r-- | tests/integration/src/android/net/ip/IpClientIntegrationTest.java | 10 |
2 files changed, 19 insertions, 3 deletions
diff --git a/src/android/net/ip/IpClientLinkObserver.java b/src/android/net/ip/IpClientLinkObserver.java index 66a4038..dc58e7b 100644 --- a/src/android/net/ip/IpClientLinkObserver.java +++ b/src/android/net/ip/IpClientLinkObserver.java @@ -282,6 +282,12 @@ public class IpClientLinkObserver implements NetworkObserver { } private final AlarmManager.OnAlarmListener mExpirePref64Alarm = () -> { + // 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. updatePref64(mShim.getNat64Prefix(mLinkProperties), mNat64PrefixExpiry, mNat64PrefixExpiry); }; @@ -321,9 +327,11 @@ public class IpClientLinkObserver implements NetworkObserver { // If we already have a prefix, continue using it and ignore the new one. Stopping and // restarting clatd is disruptive because it will break existing IPv4 connections. - // TODO: this means that if we receive an RA that adds a new prefix and deletes the old + // Note: this means that if we receive an RA that adds a new prefix and deletes the old // prefix, we might receive and ignore the new prefix, then delete the old prefix, and - // have no prefix until the next RA is received. + // have no prefix until the next RA is received. This is because the kernel returns ND + // user options one at a time even if they are in the same RA. + // TODO: keep track of the last few prefixes seen, like DnsServerRepository does. if (mNat64PrefixExpiry > now) return; // The current prefix has expired. Either replace it with the new one or delete it. diff --git a/tests/integration/src/android/net/ip/IpClientIntegrationTest.java b/tests/integration/src/android/net/ip/IpClientIntegrationTest.java index 6a5aff3..2db553e 100644 --- a/tests/integration/src/android/net/ip/IpClientIntegrationTest.java +++ b/tests/integration/src/android/net/ip/IpClientIntegrationTest.java @@ -1431,6 +1431,14 @@ public class IpClientIntegrationTest { expectNoNat64PrefixUpdate(inOrder, prefix); reset(mCb, mAlarm); + // Reduce the lifetime and expect to reschedule expiry. + pref64 = new StructNdOptPref64(prefix, 1500).toByteBuffer(); + ra = buildRaPacket(pio, rdnss, pref64); + mPacketReader.sendResponse(ra); + pref64Alarm = expectAlarmSet(inOrder, "PREF64", 1496); + expectNoNat64PrefixUpdate(inOrder, prefix); + reset(mCb, mAlarm); + // Withdraw the prefix and expect it to be set to null. pref64 = new StructNdOptPref64(prefix, 0).toByteBuffer(); ra = buildRaPacket(pio, rdnss, pref64); @@ -1456,7 +1464,7 @@ public class IpClientIntegrationTest { expectNoNat64PrefixUpdate(inOrder, prefix); reset(mCb, mAlarm); - // Withdraw the prefix and expect to switch to the new prefix. + // Withdraw the old prefix and continue to announce the new one. Expect a prefix change. pref64 = new StructNdOptPref64(prefix, 0).toByteBuffer(); ra = buildRaPacket(pio, rdnss, pref64, otherPref64); mPacketReader.sendResponse(ra); |