[sctp-dev] SCTP_EXPLICIT_COMPLETE

[Chris Hegarty]

On 29/02/2012 13:44, Amir Eliaz wrote:
> Thanks for your answer, Chris.
>
> So I now understand that the MessageInfo complete field is being ignored
> when invoking the native code.
>
> Also, the workaround in
> http://web.archiveorange.com/archive/v/9eQBGG8xraoCAJy9ieIB
> <http://web.archiveorange.com/archive/v/9eQBGG8xraoCAJy9ieIB> is not an
> option for us, since we cannot control the peers.
>
> Do you think that increasing the buffer size (SO_SNDBUF) and disabling
> fragmentation (SCTP_DISABLE_FRAGMENTS) is an acceptable solution,

You mean enabling SCTP_DISABLE_FRAGMENTS, right? If, so sounds 
reasonable to me.

-Chris.

>
> until the native API is finalized and the Java API updated accrodingly?
>
> Regards,
>
> --Amir
>
> -----Original Message-----
> From: Chris Hegarty [mailto:chris.hegarty at oracle.com]
> Sent: Wednesday, February 29, 2012 2:14 PM
> To: Michal Lefler
> Cc: Amir Eliaz; sctp-dev at openjdk.java.net; Gil Shafran
> Subject: Re: [sctp-dev] SCTP_EXPLICIT_COMPLETE
>
> Michal, Amir,
>
> This issue came up before [1], and I believe the answer is still the same.
>
> The issue is that lksctp still does not support the native
> SCTP_EXPLICIT_EOR socket option. Now that the socket extensions API has
> been finalized, RFC 6458 [1], I'm sure the various SCTP implementations
> will be revved support it. ( which should include support for
> SCTP_EXPLICIT_EOR).
>
> There is a workaround described in [1], but I'm not sure if it would be
> acceptable to you.
>
> Some background; SCTP_EXPLICIT_COMPLETE was originally added to the Java
> SCTP API so as not to have to have rev the API when the native support
> eventually came, hence it is marked as optional. I really felt that
> supporting large messages was important, but unfortunately the platform
> SCTP implementations haven't moved much over the past number of years.
>
> Hopefully now that the native API has been finalized there might be some
> renewed interest here.
>
> -Chris.
>
> [1]
>
> http://mail.openjdk.java.net/pipermail/sctp-dev/2010-February/000179.html
>
> [2] http://www.rfc-editor.org/rfc/rfc6458.txt
>
> On 29/02/2012 11:12, Michal Lefler wrote:
>
>  >
>
>  >
>
>  > Amir Eliaz<amir.eliaz at traffixsystems.com
> <mailto:amir.eliaz at traffixsystems.com>>  wrote:
>
>  >
>
>  > Hello Chris,
>
>  >     We tried testing on two different kernels:
>
>  > --  5.el6
>
>  > 2.6.32-131.0.15.el6.x86_64 #1 SMP Sat May 21 10:27:57 CDT 2011 x86_64
> x86_64 x86_64 GNU/Linux
>
>  > Lksctp-tools version 1.0.10
>
>  > -- 3.el5
>
>  > 2.6.18-194.el5 #1 SMP Fri Apr 2 14:58:14 EDT 2010 x86_64 x86_64
> x86_64 GNU/Linux
>
>  > lksctp-tools version 1.0.6
>
>  >
>
>  > In both we get the exception "Protocol not available" when trying to
> access the socket option SCTP_EXPLICIT_COMPLETE from the Java API.
>
>  >
>
>  > Regards,
>
>  > --Amir
>
>  >
>
>  > -----Original Message-----
>
>  > From: Chris Hegarty [mailto:chris.hegarty at oracle.com]
> <mailto:[mailto:chris.hegarty at oracle.com]>
>
>  > Sent: Wednesday, February 29, 2012 12:14 PM
>
>  > To: Michal Lefler
>
>  > Cc: sctp-dev at openjdk.java.net <mailto:sctp-dev at openjdk.java.net>; Gil
> Shafran; Amir Eliaz
>
>  > Subject: Re: [sctp-dev] (no subject)
>
>  >
>
>  > Hi Michal,
>
>  >
>
>  > What version of lksctp are you using? Also, what kernel?
>
>  >
>
>  > -Chris
>
>  >
>
>  > On 29/02/2012 09:15, Michal Lefler wrote:
>
>  >> Hi all.
>
>  >> We ran into the following problem.
>
>  >> Whenever we try to send sctp messages which are longer than 1024b the
>
>  >> messages are automatically splitted into two smaller messages.
>
>  >> The problem is that both messages are marked as "COMPLETED".
>
>  >> For that reason, the receiving side sees each long message as two
>
>  >> messages.
>
>  >> The first message is incomplete, while the second one is malformed.
>
>  >> We first suspected the MTU, but setting the MTU to a small value
>
>  >> resulted with a nice split (first message with an unset "COMPLETED",
>
>  >> and the second one is marked as "COMPLETED", as expected).
>
>  >> We tried to handle the "COMPLETED" flag manually, but trying to set
>
>  >> "SctpStandardSocketOption.SCTP_EXPLICIT_COMPLETE" to true caused a
>
>  >> "Protocol not supported" exception.
>
>  >> Any idea what the problem can be and how we can solve it?
>
>  >> We are using Java 1.6 u23, with the SCTP to Java 6 patch.
>
>  >> Thanks,
>
>  >> Michal.
>
>  >>
>
>  >
>
> --
>