[RFR]: 8222562: IPv6 only systems fail on setsockopt(IPV6_V6ONLY, 0)

[Arthur Eubanks]

It turns out these patches only apply to a modified kernel which has
patches to turn off IPv4. This specific patch doesn't make sense to submit
if the kernel patches are not upstream.

Maybe the entire call to setsockopt(IPV6_V6ONLY, 0) could be skipped if
IPv4 is disabled. I'll look into Daniel's suggestion of a ipv4_available()
utility.

On Wed, Apr 17, 2019 at 7:01 AM Chris Hegarty <chris.hegarty at oracle.com>
wrote:

> Arthur,
>
> On 16/04/2019 22:34, Arthur Eubanks wrote:
> > Hi,
> >
> > Copied from the bug https://bugs.openjdk.java.net/browse/JDK-8222562:
> > Some of the networking code tries to support dual socket support.
> > However, it doesn't work with IPv6 only systems.
> >
> > setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, 0) returns a failure with
> > errno EAFNOSUPPORT, and then the networking code bails. It should not
> > bail when it sees that trying to set IPV6_V6ONLY fails.
>
> I assume that you are on Linux, right? If so, have you compiled the
> Kernel without IPv4 support? How have you configured your system without
> IPv4 support?
>
> I'm curious as I would like to try something similar, as well as on
> other platforms, macOS, etc.
>
> -Chris.
>
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