[openjdk-x] Bind to a multicast address fails
vyom tewari
vyom.tewari at oracle.com
Mon Sep 10 09:22:07 UTC 2018
On Monday 10 September 2018 12:28 PM, Andre Naujoks wrote:
> 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.
Hi Andre,
i will apply your patch run our all network tests. I will update once i
will have result.
Thanks,
Vyom
>
>> -Alan
>>
>>
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