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

[Yasumasa Suenaga]

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
>>
> 
>