RFR: 8241800: Disable IPV6_MULTICAST_ALL to prevent interference from all multicast groups [v2]

[Michael McMahon]

On Fri, 16 Jun 2023 07:44:50 GMT, Alan Bateman <alanb at openjdk.org> wrote:

> Can you look at test/jdk/java/nio/channels/DatagramChannel/Promiscuous.java? I wonder if this should be updated to exercise the test with two IPv6 multicast groups? In passing, I assume the check for the OS version isn't needed in this test anymore.
> 
Okay
> As regards the new test then I think the naming should be a bit more consistent with the existing tests if possible. The existing test for IP_MULTICAST_ALL is Promiscuous so maybe the new test is PromiscuousIPv6 or something with "IPv6" in the name?
> 
Right
> The test launches "uname -r", maybe it can use the Platform test infra class instead.
> 
Ah, I missed that Platform can return the os version numbers. Will change that.
> The class initializer probes for interfaces that support IPv6 multicasting. Can this be moved to the main method so that it's easier to see in main why the test is skipping?
> 
ok
> If < 4.20 then I think the test should just skip on Linux. No need to create a socket + close it. If we have an issue here then all DatagramChannel tests would fail.
> 
ok, I just added that after the previous round. I will take it out.
> The select(2000) might not be enough on slow machines. So if we are keeping this test then I think it will need a few rounds of cleanup to make it more robust.

I'll increase that. I suspect the test doesn't need othervm mode for that matter. Will change that too.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/14491#issuecomment-1594307582