RFR 8153674: Expected SocketException not thrown when calling bind() with setReuseAddress(false)

[Chris Hegarty]

Vyom,

On 11/09/16 08:01, Vyom Tewari wrote:
> Hi All,
>
> Please review the below code change.
>
> Bug        : https://bugs.openjdk.java.net/browse/JDK-8153674
>
> Webrev  :
> http://cr.openjdk.java.net/~vtewari/8153674/webrev0.0/index.html
> <http://cr.openjdk.java.net/%7Evtewari/8153674/webrev0.0/index.html>
>
> This change override the "get/setReuseAddress"  for MulticaseSocket and
> will abstract with both reuse attributes(SO_REUSEADDR & SO_REUSEPORT).

This issue arises since the changes for 6432031 "Add support for 
SO_REUSEPORT" [1], which sets SO_REUSEPORT on MulticastSocket, if
the available. So setting setReuseAddress(false) alone is no longer
sufficient to disable address/port reuse, one must also set
SO_REUSEPORT to false.

I would be really nervous about changing set/getReuseAddress, without
at least updating the javadoc to indicate that it is now, for MS,
operating on two socket options.  Although, I do have sympathy
here since SO_REUSEPORT and SO_REUSEADDR are almost identical when
dealing with multicasting.

An alternative, maybe; Since the MS constructors document that
SO_REUSEPORT will be set, where available, maybe a javadoc note
on the set/getReuseAddress methods would be sufficient, that
indicates that StandardSocketOptions#SO_REUSEPORT may also need
to be set to have the desired effect?

If so, then code would have to:

     setReuseAddress(false);

     if (supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT))
         this.setOption(StandardSocketOptions.SO_REUSEPORT, false);

   , but at least it is explicit.

Q: not all MS constructors document that SO_REUSEPORT is set, but
they should, right? This seems to have slipped past during 6432031 [1].

-Chris.

[1] https://bugs.openjdk.java.net/browse/JDK-6432031