I'll do the testing on AIX.
Thanks,
Volker
On Mon, Nov 23, 2015 at 6:35 PM, Michael McMahon
<michael.x.mcma...@oracle.com> wrote:
> Lucy,
>
> We can run the change through the standard test system here that will check
> it out on all platforms.
>
> Alan mentioned to me earlier that we could tweak the wording that I
> suggested
> to be more consistent with other options. So, I just need to check that with
> him.
>
> Thanks
> Michael.
>
>
> On 23/11/15 17:21, Lu, Yingqi wrote:
>>
>> Michael/Volker/Alan,
>>
>> Thank you all very much for your feedback!
>>
>> Michael, I like your wording for SO_REUSEPORT in
>> java.net.StandardSocketOptions and I will remove the link to the Linux page.
>> It will be updated for the next version of the patch. Regarding to
>> "reference this text from everywhere else", do you mean doing something like
>> {@see StandardSocketOptions#SO_REUSEPORT}?
>>
>> Michael/Volker, yes, I agree that we should enable this feature on all the
>> supporting platforms. I will try to add the code in the next version as
>> well. However, I do not have all the OSes so that I might not be able to
>> test them. Can any of you please help with the testing?
>>
>> Alan, I will add the isReusePortSupported method in the Net.c and only add
>> SO_REUSEPORT into the options set only when it is supported.
>>
>> Thank you,
>> Lucy
>>
>> -----Original Message-----
>> From: Michael McMahon [mailto:michael.x.mcma...@oracle.com]
>> Sent: Monday, November 23, 2015 3:42 AM
>> To: Volker Simonis <volker.simo...@gmail.com>; Alan Bateman
>> <alan.bate...@oracle.com>
>> Cc: Kharbas, Kishor <kishor.khar...@intel.com>; net-dev@openjdk.java.net;
>> Lu, Yingqi <yingqi...@intel.com>
>> Subject: Re: Patch for adding SO_REUSEPORT socket option
>>
>> How about the following for the apidoc in j.n.StandardSocketOptions?
>>
>> We can then reference this text from everywhere else rather than repeating
>> it.
>>
>> (just noticed Lucy was not included in the last few mails)
>>
>> - Michael
>>
>> /**
>> * Re-use port.
>> *
>> * <p> The value of this socket option is a {@code Boolean} that
>> represents
>> * whether the option is enabled or disabled. The exact semantics of
>> this
>> * socket option are socket type and system dependent.
>> *
>> * SO_REUSEPORT can be used with both TCP and UDP sockets.
>> *
>> * <p> In the case of stream-oriented sockets, this socket option
>> allows
>> * multiple listening sockets to be bound to both the same address
>> * and same port.
>> *
>> * <p> For datagram-oriented sockets the socket option is used to
>> allow
>> * multiple UDP sockets to be bound to the same address and port.
>> *
>> * @implNote Generally, this option must be set before the
>> * socket is bound or connected. Changing the value of this socket
>> option
>> * after the socket is bound has no effect. There may be further
>> * restrictions imposed by implementations such as the requirement
>> that
>> * all sockets bound to the same port, must have set the option.
>> */
>>
>> On 23/11/15 10:54, Michael McMahon wrote:
>>>
>>> I agree we should enable the option on all platforms.
>>> We can add the code to do that and run the tests.
>>>
>>> On the existing use of SO_REUSEPORT on AIX and Mac it appears that is
>>> set to emulate expected behavior on other platforms when SO_REUSEADDR
>>> is set for datagram sockets.
>>> The expectation is that ports can be reused for datagram sockets and
>>> the JCK tests this. So, I guess we have to leave this behavior by
>>> default, except if SO_REUSEPORT is explicitly disabled maybe. Though
>>> this code hasn't been forward ported to JDK 9 yet.
>>>
>>> For reference, SO_REUSEPORT on Linux is documented here
>>> http://man7.org/linux/man-pages/man7/socket.7.html
>>>
>>> - Michael
>>>
>>> On 23/11/15 09:13, Volker Simonis wrote:
>>>>
>>>> Hi Lucy,
>>>>
>>>> in general I support the addition of SO_REUSEPORT to the set of
>>>> standard socket options. However for me the problem is not that this
>>>> new option is not supported on all platforms, but instead that it has
>>>> such different semantics on different platforms. If you look at the
>>>> code, you'll see that we already implicitly set SO_REUSEPORT on Mac
>>>> and AIX for datagram sockets for which we set SO_REUSEADDR. So maybe
>>>> we have to rethink this, once SO_REUSEPORT becomes available as a
>>>> standard socket option.
>>>>
>>>> I like the new wording you've posted for JavaDoc of SO_REUSEPORT, but
>>>> I think the sentence:
>>>>
>>>> * Although SO_REUSEADDR option already enables similar
>>>> * functionality, SO_REUSEPORT prevents port hijacking and
>>>> * distributes the involving datagrams evenly across all of the
>>>> * receiving threads.
>>>>
>>>> refers to a Linux-specific implementation detail which shouldn't be
>>>> mentioned in the general documentation. You already have the sentence
>>>> "The exact semantics of this socket option are socket type and system
>>>> dependent" which should let everybody think twice before using this
>>>> option. I'm also not sure about the link to the Linux article but I
>>>> again think it is inappropriate in a general API documentation
>>>> (otherwise we would have to add links for every platform which
>>>> supports SO_REUSEPORT).
>>>>
>>>> As far as I can see (and please correct me if I'm wrong) you actually
>>>> only add the new option for Linux platforms. But this socket option
>>>> is also supported on Solaris (>= 11), MacOS X, AIX. So could you
>>>> please enable it on the other platforms as well.
>>>>
>>>> Finally I want to mention the good stackoverflow article at
>>>> http://stackoverflow.com/questions/14388706/socket-options-so-reusead
>>>> dr-and-so-reuseport-how-do-they-differ-do-they-mean-t
>>>>
>>>> which covers the topic SO_REUSEADDR vs. SO_REUSEPORT quite well. And
>>>> I've collected the man-page entries for SO_REUSEADDR and SO_REUSEPORT
>>>> for the systems I have (unfortunately, I couldn't find an updated
>>>> Linux man-page which mentions SO_REUSEPORT):
>>>>
>>>> Linux
>>>> =====
>>>>
>>>> SO_REUSEADDR
>>>> Indicates that the rules used in validating addresses
>>>> supplied in a bind(2) call should allow reuse of local
>>>> addresses. For AF_INET sockets this means that a socket
>>>> may bind, except when there is an active listening
>>>> socket bound to the address. When the listening socket
>>>> is bound to INADDR_ANY with a specific port then it is
>>>> not possi- ble to bind to this port for any local
>>>> address. Argument is an integer boolean flag.
>>>>
>>>> Linux will only allow port reuse with the SO_REUSEADDR option
>>>> when this option was set both in the previous program that
>>>> performed a bind(2) to the port and in the program that wants
>>>> to reuse the port. This differs from some implementations
>>>> (e.g., FreeBSD) where only the later program needs to set the
>>>> SO_REUSEADDR option. Typically this difference is invisi- ble,
>>>> since, for example, a server program is designed to always set
>>>> this option.
>>>>
>>>> MacOS X
>>>> =======
>>>> SO_REUSEADDR enables local address reuse
>>>> SO_REUSEPORT enables duplicate address and port bindings
>>>>
>>>> SO_REUSEADDR indicates that the rules used in validating
>>>> addresses supplied in a bind(2) call should allow reuse of local
>>>> addresses.
>>>>
>>>> SO_REUSEPORT allows completely duplicate bindings by multiple
>>>> processes if they all set SO_REUSEPORT before bind- ing the port.
>>>> This option permits multiple instances of a program to each
>>>> receive UDP/IP multicast or broadcast datagrams destined for the
>>>> bound port.
>>>>
>>>> Solaris
>>>> =======
>>>>
>>>> SO_REUSEADDR enable/disable local address reuse
>>>>
>>>>
>>>> SO_REUSEPORT enable/disable local port reuse for
>>>> PF_INET/PF_INET6 socket
>>>>
>>>> The SO_REUSEADDR/SO_REUSEPORT options indi- cate that the rules
>>>> used in validating addresses and ports supplied in a
>>>> bind(3SOCKET) call should allow reuse of local addresses or
>>>> ports.
>>>>
>>>> AIX
>>>> ===
>>>>
>>>> SO_REUSEADDR
>>>> Specifies that the rules used in validating
>>>> addresses supplied by a bind subroutine should
>>>> allow reuse of a local port. A particular IP
>>>> address can only be bound once to the same
>>>> port. This option enables or disables reuse of
>>>> local ports.
>>>>
>>>> SO_REUSEADDR allows an application to explicitly
>>>> deny subsequent bind subroutine to the port/address
>>>> of the socket with SO_REUSEADDR set. This allows an
>>>> application to block other applications from
>>>> binding with the bind subroutine.
>>>>
>>>> SO_REUSEPORT
>>>> Specifies that the rules used in validating
>>>> addresses supplied by a bind subroutine should
>>>> allow reuse of a local port/address
>>>> combination. Each binding of the port/address
>>>> combination must specify the SO_REUSEPORT socket
>>>> option. This option enables or disables the reuse
>>>> of local port/address combinations.
>>>>
>>>> HPUX
>>>> ====
>>>>
>>>> SO_REUSEADDR
>>>> (int; boolean; AF_INET sockets only) If enabled, allows
>>>> a local address to be reused in subsequent calls to
>>>> bind(). Default: disallowed.
>>>>
>>>> SO_REUSEPORT
>>>> (int; boolean; AF_INET sockets only) If enabled, allows
>>>> a local address and port to be reused in subsequent
>>>> calls to bind(). Default: disallowed.
>>>>
>>>> Setting the SO_REUSEADDR option allows the local socket address
>>>> to be reused in subsequent calls to bind(). This permits
>>>> multiple SOCK_STREAM sockets to be bound to the same local
>>>> address, as long as all existing sockets with the desired local
>>>> address are in a connected state before bind() is called for a
>>>> new socket. For SOCK_DGRAM sockets, SO_REUSEADDR allows
>>>> multiple sockets to receive UDP multicast datagrams addressed to
>>>> the bound port number. For all SOCK_DGRAM sockets bound to the
>>>> same local address, SO_REUSEADDR must be set before calling
>>>> bind().
>>>>
>>>> Setting the SO_REUSEPORT option allows multiple SOCK_DGRAM
>>>> sockets to share the same address and port. Each one of those
>>>> sockets, including the first one to use that port, must specify
>>>> this option before calling bind().
>>>>
>>>> Regards,
>>>> Volker
>>>>
>>>>
>>>> On Mon, Nov 23, 2015 at 9:00 AM, Alan Bateman
>>>> <alan.bate...@oracle.com> wrote:
>>>>>
>>>>> On 23/11/2015 04:12, Lu, Yingqi wrote:
>>>>>
>>>>> Hi Alan,
>>>>>
>>>>>
>>>>>
>>>>> One more question please J I want to make sure I understand
>>>>> correctly on your following suggestion. In order to use
>>>>> supportedOptions method to test SO_REUSEPORT, I will need to first
>>>>> write a native function to check if SO_REUSEPORT is supported. Then,
>>>>> in the defaultOptions method, I do a conditional add for
>>>>> StandardSocketOptions.SO_REUSEPORT if it is supported on the
>>>>> platform? Is this a preferred way to implement? Please let me know!
>>>>>
>>>>>
>>>>> Yes as supportedOptions() shouldn't return SO_REUSEPORT in the set
>>>>> when it's not supported. It might be simplest to put that code in
>>>>> sun.nio.ch.Net, maybe isReusePortSupported or some such method. In
>>>>> the implementation
>>>>> (Net.c) then you can return true or false depending on the platform
>>>>> and maybe kernel version.
>>>>>
>>>>> -Alan
>
>
