RFR: 8308807: [AIX] MulticastSocket and jdp test fails due to joinGroup

[Alan Bateman]

On Mon, 12 Jun 2023 11:09:32 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>>> @MBaesken @RealCLanger I wonder if you might have a bit of time to comment on this issue. If I read Deepa's comment correctly, she is saying that IPv6 UDP sockets on AIX cannot join IPv4 multicast groups. The spec doesn't require this but it problematic for MulticastSocket (as it has been since Java 4 when IPv6 was added). The part that I'm wondering about is why this issue might be coming up now. As I understand, SAP have supporting/maintaining/testing on AIX for a long time. Maybe your systems don't have IPv6 enabled so you never run into this?
>> 
>> Well, in that area we always had deviations on AIX, so definitely this rings a bell. However, since AIX was not the most important platform for us and that particular IPv6/IPv4 multicast feature didn't seem to be mission critical and wouldn't fail TCK tests, we rather resorted to excluding some tests internally, I believe. But it would be good to really resolve this compatibility/spec/documentation issue, if possible.
>
>> Well, in that area we always had deviations on AIX, so definitely this rings a bell. However, since AIX was not the most important platform for us and that particular IPv6/IPv4 multicast feature didn't seem to be mission critical and wouldn't fail TCK tests, we rather resorted to excluding some tests internally, I believe. But it would be good to really resolve this compatibility/spec/documentation issue, if possible.
> 
> Thanks. So yes, if some/all of the tests for multicasting were excluded then it helps explain why it didn't come up. The spec doesn't require that a DatgaramSocket or DatagramChannel to an IPv6 socket be capable of joining an IPv4 multicast group. So the tests in several areas might need updates as I don't think we've had a platform to date where it wasn't possible.

> @AlanBateman , is it possible if there is a central place where the change could me made for fixing all of the multicast test cases?

Your starting point is probably to exclude all of the tests that are failing. This will be tests for DatagramSocket/MulticastSocket, DatagramChannel and the tests for the JMX agent that use the discovery protocol. Once they are excluded then you can start working through the issues.

For the JMX agent, then I would expect that if if the system property com.sun.management.jdp.address is configured then the protocol family is known so it should be possible to create the DatagramChannel to use that protocol family. It might so already, but you can check that.

For the networking and NIO tests then you probably should look at jdk.test.lib.NetworkConfiguration. That has a number of AIX specific comments that may be out of date. After that I think you will need to work through the tests one by one. Between NetworkConfiguration and jdk.test.lib.net.IPSupport, I would expect you have all the infrastructure needed for the tests to not attempt to join IPv4 multicast groups when IPSupport.hasIPv6() is true.

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PR Comment: https://git.openjdk.org/jdk/pull/14142#issuecomment-1588666107