On 9/9/18 9:16 AM, Alan Bateman wrote:
> On 07/09/2018 13:22, Andre Naujoks wrote:
>> :
>> I have not tried joining IPv4 groups on an IPv6 socket through java,
>> since we do not use IPv4 at all in this particular environment. I have
>> tried setting IP_MULTICAST_ALL to 0 in the IPv6 scenario (in a C++
>> project), hoping it would help, but it did not. Hence the patch for the
>> linux kernel.
>>
>> Would it actually help, if I tried the IPv4 multicast group bind on an
>> IPv6 socket?
>>
>> The bind to an address would be a workaround for the missing
>> IPV6_MULTICAST_ALL handling.
>>
> The tests that we have for the scenario of two sockets bound to the same
> port but joining different multicast groups seems to be mostly using
> IPv4 multicast addresses so one thing out this discussion is that we may
> need to expand the tests to IPv6 multicast addresses. As the existing
> tests use IPv6 sockets (when not disabled on the system or in the test
> run) then it means they are exercising IP_MULTICAST_ALL=0 so I think we
> can conclude that disabling IP_MULTICAST_ALL works correctly for IPv6
> sockets when joining IPv4 multicast groups. If the tests were expanded
> to IPv6 multicast groups then I assume we will run into the need for
> IPV6_MULTICAST_ALL too.
Yes, I would assume the same. That was the whole reason for the kernel
patch.
>
> As regards the patch to NET_InetAddressToSockaddr to set the scope_id
> then it looks correct but need testing (both for bind and connect). I
> see JDK-8210493 has been picked up by Vyom.
Please test it! This is my very first look into the java code-base. The
patch does what it says, but I cannot rule out, that it doesn't have any
unintended side effects.
>
> -Alan
>
>
