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

[Alan Bateman]

On Thu, 25 May 2023 07:14:19 GMT, Deepa Kumari <duke at openjdk.org> wrote:

> DatagramSocket delegates to an inner DatagramSocket object. Irrespective of whether datagramSocket is IPv4 or IPv6, we create an IPv6 datagramChannel as its's delegate. So, This can cause problems with operations like joinGroup. 
> 
> On AIX, IPv6 datagramSocket can not join an IPv4 multicast group.
> 
> These failures can be fixed by making sure that the delegate created for a datagram socket has the same protocol family. 
> 
> 
> 
> 
> Reported Issue : [JDK-8308807](https://bugs.openjdk.org/browse/JDK-8308807)

@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 what 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?

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PR Comment: https://git.openjdk.org/jdk/pull/14142#issuecomment-1585521766