RFR: JDK-8057556: JDP should better handle non-active interfaces

[Yasumasa Suenaga]

Hi Jaroslav,

I could not receive your email.
So I reply from another email.

> L103 Please, move "else" to the previous line

I will fix it.

> L96-100 Do we still need these lines? Isn't
> `channel.setOption(StandardSocketOptions.IP_MULTICAST_IF, interf);`
> enough to listen on the interface?

I think we should remove bind() call.
If we run multiple VM with same com.sun.management.jdp.source_addr value
and on same OS, we may encounter BindException in current implementation
as following:

----------
Error: Exception thrown by the agent : java.rmi.server.ExportException: Port already in use: 7091; nested exception is:
         java.net.BindException: Address already in use
----------

If it should be treated as another issue, I will file it to JBS and
create a new patch.

I will upload new webrev for JDK-8057556 after this discussion.


Thanks,

Yasumasa


(2014/09/05 19:28), Yasumasa Suenaga wrote:
> Hi Peter,
>
> I fixed it and created new webrev.
> http://cr.openjdk.java.net/~ysuenaga/JDK-8057556/webrev.1/
>
> Could you review it again?
>
>
> Thanks,
>
> Yasumasa
>
>
> (2014/09/05 17:20), Peter Allwin wrote:
>> Looks like only the first Interface will be considered if no srcAddress is provided (succeeded will be false and we will throw to exit the while loop). Is this intended?
>>
>> Thanks!
>> /peter
>>
>>> On 4 sep 2014, at 17:59, Yasumasa Suenaga <yasuenag at gmail.com> wrote:
>>>
>>> Hi all,
>>>
>>> Thank you so much, Dmitry!
>>>
>>> I've created webrev for it.
>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8057556/webrev.0/
>>>
>>> Please review.
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>> (2014/09/04 21:26), Dmitry Samersoff wrote:
>>>> Yasumasa,
>>>>
>>>> The CR number is JDK-8057556
>>>>
>>>> I'll care about it's integration.
>>>>
>>>> -Dmitry
>>>>
>>>>> On 2014-09-02 18:52, Yasumasa Suenaga wrote:
>>>>> Hi all,
>>>>>
>>>>> I'm trying to use JDP on my Fedora20 machine.
>>>>> My machine has two NICs and only one NIC is up.
>>>>>
>>>>> I passed system properties as below, however JDP broadcaster
>>>>> thread was not started:
>>>>>
>>>>>    -Dcom.sun.management.jmxremote.port=7091
>>>>>    -Dcom.sun.management.jmxremote.authenticate=false
>>>>>    -Dcom.sun.management.jmxremote.ssl=false
>>>>>    -Dcom.sun.management.jmxremote.autodiscovery=true
>>>>>    -Dcom.sun.management.jdp.name=TEST
>>>>>
>>>>> I checked exceptions with jdb, SocketException was occurred in
>>>>> JDPControllerRunner#run(), and it was caused by another NIC
>>>>> is down.
>>>>>
>>>>> Currently, DiagramChannel which is used in JDPBroadcaster
>>>>> tries to send JDP packet through all "UP" NICs.
>>>>> However, NIC which is controlled by NetworkManager seems to
>>>>> be still "UP" when ifdown command is executed.
>>>>> (It seems to be removed IP address from NIC only.)
>>>>>
>>>>>
>>>>> This problem may be Fedora, however I think it should be
>>>>> improved in JDK.
>>>>> I've created a patch as below, and it works fine in my environment.
>>>>> (jdk9/dev/jdk)
>>>>>
>>>>> If this patch may be accepted, I will file this to JBS.
>>>>>
>>>>> --------------------
>>>>> diff -r 68a6bb51cb26 src/java.management/share/classes/sun/management/jdp/JdpBroadcaster.java
>>>>> --- a/src/java.management/share/classes/sun/management/jdp/JdpBroadcaster.java    Mon Sep 01 13:33:28 2014 +0200
>>>>> +++ b/src/java.management/share/classes/sun/management/jdp/JdpBroadcaster.java    Tue Sep 02 23:25:50 2014 +0900
>>>>> @@ -35,6 +35,7 @@
>>>>>   import java.nio.ByteBuffer;
>>>>>   import java.nio.channels.DatagramChannel;
>>>>>   import java.nio.channels.UnsupportedAddressTypeException;
>>>>> +import java.util.Enumeration;
>>>>>
>>>>>   /**
>>>>>    * JdpBroadcaster is responsible for sending pre-built JDP packet across a Net
>>>>> @@ -79,6 +80,15 @@
>>>>>           if (srcAddress != null) {
>>>>>               // User requests particular interface to bind to
>>>>>               NetworkInterface interf = NetworkInterface.getByInetAddress(srcAddress);
>>>>> +
>>>>> +            if (interf == null) {
>>>>> +                throw new JdpException("Unable to get network interface for " + srcAddress.toString());
>>>>> +            }
>>>>> +
>>>>> +            if (!interf.isUp() || !interf.supportsMulticast()) {
>>>>> +                throw new JdpException(interf.getName() + " does not support multicast.");
>>>>> +            }
>>>>> +
>>>>>               try {
>>>>>                   channel.bind(new InetSocketAddress(srcAddress, 0));
>>>>>               } catch (UnsupportedAddressTypeException ex) {
>>>>> @@ -86,6 +96,23 @@
>>>>>               }
>>>>>               channel.setOption(StandardSocketOptions.IP_MULTICAST_IF, interf);
>>>>>           }
>>>>> +        else {
>>>>> +            Enumeration<NetworkInterface> nics = NetworkInterface.getNetworkInterfaces();
>>>>> +            while (nics.hasMoreElements()) {
>>>>> +                NetworkInterface nic = nics.nextElement();
>>>>> +
>>>>> +                if (nic.isUp() && nic.supportsMulticast()) {
>>>>> +                    try {
>>>>> +                        channel.setOption(StandardSocketOptions.IP_MULTICAST_IF, nic);
>>>>> +                    } catch (IOException ex) {
>>>>> +                        System.err.println("WARNING: JDP broadcaster cannot use " + nic.getName() + ": " + ex.getMessage());
>>>>> +                    }
>>>>> +                }
>>>>> +
>>>>> +            }
>>>>> +
>>>>> +        }
>>>>> +
>>>>>       }
>>>>>
>>>>>       /**
>>>>> --------------------
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Yasumasa
>>>>
>>>>