[reSIProcate] Matching INFO requests and responses

Thu Dec 9 13:16:12 CST 2010

Hi,

(thanks to you both for the suggestions and examples :))

I went ahead and did a first working implementation:
https://svn.resiprocate.org/rep/resiprocate/branches/b-nit-contents-20101209/

I cached it as a smart pointer (SharedPtr<SipMessage>) since that is what we
are passing around anyway in the code. If we cached a copy instead, wouldn't
we loose things like the branch parameter and other things set in
DUM::send()?

If no NIT request was sent, then users can validate the SharedPtr using the
implicit conversion to bool (i.e. assert(mySharedPtr)).

I've also modified BasicCall.cxx to test it (using both INFO and MESSAGE). I
added assertions to ensure that it works and I also ran it under Valgrind on
Linux. I will test it on Windows shortly.

Feel free to comment,
Francis

On Thu, Dec 9, 2010 at 12:27 PM, Scott Godin <sgodin at sipspectrum.com> wrote:

> The other InviteSession API's return objects by reference (ie. SipMessage&)
> - you just need to handle the case when a caller accesses the new API and
> you don't have a previous NIT request to return - returning a reference to a
> static empty SipMessage makes sense for this case
> (see InviteSession::getLocalOfferAnswer for an example.
>
> Scott
>
> On Thu, Dec 9, 2010 at 12:02 PM, Aron Rosenberg <arosenberg at logitech.com>wrote:
>
>> The only "main" reason to expand the callback API was to try and match
>> ClientPagerMessageHandler...but I can rework the API to still keep the
>> last request in the NIT queue but expose a new method on InviteSession
>> called getLastNITRequest() . Should that return a
>> auto_ptr<SipMessage>, const SipMessage* or something else?
>>
>> -Aron
>>
>>
>> On Thu, Dec 9, 2010 at 6:53 AM, Scott Godin <sgodin at sipspectrum.com>
>> wrote:
>> > That works for me too - in fact if you are going with this approach,
>> then
>> > you may as well store the entire last IT request and make it available
>>
>> > instead of just the contents.  A branch sounds like a good idea.  : )
>> > Thanks,
>> > Scott
>> >
>> > On Thu, Dec 9, 2010 at 9:44 AM, Francis Joanis <
>> francis.joanis at gmail.com>
>> > wrote:
>> >>
>> >> Hi,
>> >> What about the following: rather than changing the DUM callbacks we
>> could
>> >> expose a reader to get the last Contents that was sent as a NIT? A bit
>> like
>> >> InviteSession::getRemoteSdp().
>> >> That way, if someone wants to access it, it can simply be done in the
>> on*
>> >> callbacks. It would be cleaner in the sense that it won't change the
>> >> interfaces at all.
>> >> I will take care of ensuring that the memory is properly managed
>> (helped
>> >> by valgrind). I was thinking of cloning the contents of the message
>> then
>> >> assigning it to an auto_ptr as a member of InviteSession.
>> >> I also want to code a test suite to ensure that it works for INFO,
>> >> MESSAGE. We also need to ensure that it doesn't screw up the REFERs
>> since
>> >> currently nitComplete() is also called from Dialog.cxx.
>> >> I was thinking of creating a branch to do this:
>> b-nit-contents-20101209.
>> >> Scott, let me know if you think that would be a bad idea ;)
>> >> I'll let you know of my progress.
>> >> Francis
>> >>
>> >> On Thu, Dec 9, 2010 at 1:43 AM, Aron Rosenberg <
>> arosenberg at logitech.com>
>> >> wrote:
>> >>>
>> >>> I coded up a working patch based on Scott's feedback. The only
>> >>> difference is that neither set of callbacks are pure-virtual now. I
>> >>> figure this was better moving forward so that new code didn't need to
>> >>> reference the old handler. It also seems that dealing with the
>> >>> responses to INFO and MESSAGE aren't needed by most normal UA's. I
>> >>> tested this patch with MESSAGE requests on the wire and it works.
>> >>>
>> >>> My only worry with this patch is that the memory handling semantics
>> >>> are correct. mNITQueue holds SharedPtr<SipMessage> and it seems ok for
>> >>> that to stay valid after dum.send() has been called. On the callback
>> >>> we pass a const Contents* rather than an auto_ptr since we can't get
>> >>> an auto_ptr from SipMessage for Contents without a clone call. I
>> >>> figure the developer who needs this longer than the life of the
>> >>> callback can clone themselves.
>> >>>
>> >>> Francis: Can you test the INFO side to make sure you are getting the
>> >>> right data back.
>> >>>
>> >>> -Aron
>> >>>
>> >>>
>> >>> On Wed, Dec 8, 2010 at 1:56 PM, Scott Godin <sgodin at sipspectrum.com>
>> >>> wrote:
>> >>> > I think we could add the new callback and leave the old one place.
>>  The
>> >>> > new
>> >>> > handler would not be virtual, and the default handler for the new
>> >>> > callback
>> >>> > would just throw away the contents and call the old callback.  This
>> >>> > will
>> >>> > allow current applications to use the new dum version without any
>> code
>> >>> > changes.  For applications that want to see the Contents, they would
>> >>> > need to
>> >>> > implement both callbacks, but the old callback can be left blank as
>> it
>> >>> > will
>> >>> > never get called.
>> >>> > Scott
>> >>> >
>> >>> > On Wed, Dec 8, 2010 at 4:36 PM, Aron Rosenberg
>> >>> > <arosenberg at logitech.com>
>> >>> > wrote:
>> >>> >>
>> >>> >> The major use-case we need to fix is this:
>> >>> >>
>> >>> >> InviteSession based MESSAGE requests where the far end returns 415
>> >>> >> (mime-type invalid) for some types (text/plain works, but text/html
>> >>> >> doesn't, application/im-iscomposing+xml doesn't). Without the
>> >>> >> Contents* of the request that failed, we can't tell which type
>> failed
>> >>> >> to determine if we need to notify the user sending the message.
>> >>> >>
>> >>> >> Scott: You have an opinion on if changing the callback type is an
>> ok
>> >>> >> way to proceed?
>> >>> >>
>> >>> >> Francis: I have attached a prototype patch for this, it has only
>> been
>> >>> >> compile tested if you want to try it and flesh it out some more.
>> >>> >>
>> >>> >> -Aron
>> >>> >>
>> >>> >> On Wed, Dec 8, 2010 at 12:39 PM, Francis Joanis
>> >>> >> <francis.joanis at gmail.com> wrote:
>> >>> >> > Hi,
>> >>> >> > I like what you are proposing since any user-specific information
>> >>> >> > would
>> >>> >> > go
>> >>> >> > in the user-derived Contents object: it acts a bit like an
>> >>> >> > AppDialog/Set
>> >>> >> > in
>> >>> >> > that sense.
>> >>> >> > We could even implement this by only caching the Contents of the
>> >>> >> > last
>> >>> >> > sent
>> >>> >> > NIT request, since they're all sent serially (so no need to do
>> the
>> >>> >> > extra
>> >>> >> > management on mNITQueue). This would mainly require adding a new
>> >>> >> > member
>> >>> >> > variable (probably an auto_ptr<Contents>) to InviteSession and
>> >>> >> > changing
>> >>> >> > the
>> >>> >> > various on* callbacks in InviteSessionHandler.
>> >>> >> > In the case of the REFER (which is also using mNITQueue), it
>> would
>> >>> >> > most
>> >>> >> > likely have a NULL Contents, so it could get ignored on the
>> >>> >> > callbacks
>> >>> >> > (i.e.
>> >>> >> > no need to modify the onRefer* callbacks).
>> >>> >> > I started playing around with the code but I'd like to know if
>> such
>> >>> >> > a
>> >>> >> > change
>> >>> >> > would be a good one or not from the perspective of the more
>> >>> >> > experienced
>> >>> >> > developers. Changing callback APIs seems like a somewhat major
>> >>> >> > change
>> >>> >> > (i.e.
>> >>> >> > it will break current apps) and I wouldn't want to do it unless
>> >>> >> > there is
>> >>> >> > really a good use case.
>> >>> >> > Regards,
>> >>> >> > Francis
>> >>> >> >
>> >>> >> >
>> >>> >> > On Wed, Dec 8, 2010 at 1:32 PM, Aron Rosenberg
>> >>> >> > <arosenberg at logitech.com>
>> >>> >> > wrote:
>> >>> >> >>
>> >>> >> >> For a slightly different issue (matching 415's to outbound
>> MESSAGE
>> >>> >> >> requests) I was looking at modifying InviteSession to remove the
>> >>> >> >> SipMessage* from the mNITQueue upon end of transaction rather
>> than
>> >>> >> >> beginning of transaction. We could then pass up the Contents*
>> like
>> >>> >> >> is
>> >>> >> >> done with ClientPagerMessage.
>> >>> >> >>
>> >>> >> >> onMessageSuccess(resip::InviteSessionHandle ish, const
>> >>> >> >> resip::SipMessage&status) would become
>> >>> >> >> onMessageSuccess(resip::InviteSessionHandle ish, const
>> >>> >> >> resip::SipMessage&status, std::auto_ptr<Contents> contents)
>> >>> >> >> onMessageFailure(resip::InviteSessionHandle ish, const
>> >>> >> >> resip::SipMessage &status) would become
>> >>> >> >> onMessageFailure(resip::InviteSessionHandle ish, const
>> >>> >> >> resip::SipMessage &status, std::auto_ptr<Contents> contents)
>> >>> >> >>
>> >>> >> >> This would also work in the INFO cases with the same changes to
>> add
>> >>> >> >> std::auto_ptr<Contents> contents to the callbacks.
>> >>> >> >>
>> >>> >> >> I also attempted to try the other way, dig into the
>> >>> >> >> TransactionController / TU and create a "SipMessage*
>> >>> >> >> findLastRequestForResponse(SipMessage*)" that used the tid, but
>> >>> >> >> this
>> >>> >> >> would require adding a number of public functions to SipStack,
>> >>> >> >> TransactionMap and some other classes.
>> >>> >> >>
>> >>> >> >> -Aron
>> >>> >> >>
>> >>> >> >> Aron Rosenberg
>> >>> >> >> Logitech Inc. (SightSpeed Group)
>> >>> >> >>
>> >>> >> >>
>> >>> >> >>
>> >>> >> >> On Wed, Dec 8, 2010 at 10:08 AM, Francis Joanis
>> >>> >> >> <francis.joanis at gmail.com> wrote:
>> >>> >> >> > So I guess it leaves me with the original workaround of
>> >>> >> >> > leveraging
>> >>> >> >> > the
>> >>> >> >> > fact
>> >>> >> >> > that all NITs are sequential. Also I think I could use an
>> >>> >> >> > outgoing
>> >>> >> >> > DumFeature to inspect outgoing messages, but that would be
>> called
>> >>> >> >> > for
>> >>> >> >> > all
>> >>> >> >> > outgoing messages, which will impact performance.
>> >>> >> >> > Thanks,
>> >>> >> >> > Francis
>> >>> >> >> >
>> >>> >> >> > On Wed, Dec 8, 2010 at 11:28 AM, Scott Godin
>> >>> >> >> > <sgodin at sipspectrum.com>
>> >>> >> >> > wrote:
>> >>> >> >> >>
>> >>> >> >> >> The branch parameter is "reset" in DialogUsageManager send
>> (ln
>> >>> >> >> >> 824)
>> >>> >> >> >> -
>> >>> >> >> >> so
>> >>> >> >> >> it won't help to store the branch parameter in the message
>> >>> >> >> >> created
>> >>> >> >> >> (same
>> >>> >> >> >> applies for onReadyToSend).
>> >>> >> >> >> Scott
>> >>> >> >> >>
>> >>> >> >> >> On Wed, Dec 8, 2010 at 11:08 AM, Francis Joanis
>> >>> >> >> >> <francis.joanis at gmail.com>
>> >>> >> >> >> wrote:
>> >>> >> >> >>>
>> >>> >> >> >>> Hi Scott,
>> >>> >> >> >>> Thanks for your reply.
>> >>> >> >> >>> What about if we changed InviteSession::info/refer/message
>> to
>> >>> >> >> >>> return a
>> >>> >> >> >>> _copy_ of the constructed SipMessage rather than returning
>> >>> >> >> >>> void?
>> >>> >> >> >>> I ran a quick test and it looks like the transaction id is
>> set
>> >>> >> >> >>> when
>> >>> >> >> >>> the
>> >>> >> >> >>> message is constructed. That way, I can immediately cache
>> the
>> >>> >> >> >>> SIP
>> >>> >> >> >>> transaction id to pair it with my "key". This removes the
>> need
>> >>> >> >> >>> for
>> >>> >> >> >>> my
>> >>> >> >> >>> extra
>> >>> >> >> >>> "key list" and does not require message inspection in
>> >>> >> >> >>> onReadyToSend.
>> >>> >> >> >>> (I've also attached a patch to do this.)
>> >>> >> >> >>> Thanks,
>> >>> >> >> >>> Francis
>> >>> >> >> >>>
>> >>> >> >> >>> On Wed, Dec 8, 2010 at 9:12 AM, Scott Godin
>> >>> >> >> >>> <sgodin at sipspectrum.com>
>> >>> >> >> >>> wrote:
>> >>> >> >> >>>>
>> >>> >> >> >>>> ...inline...
>> >>> >> >> >>>>
>> >>> >> >> >>>> On Tue, Dec 7, 2010 at 8:40 PM, Francis Joanis
>> >>> >> >> >>>> <francis.joanis at gmail.com> wrote:
>> >>> >> >> >>>>>
>> >>> >> >> >>>>> Hi guys,
>> >>> >> >> >>>>> I have a question about sending multiple NIT messages
>> >>> >> >> >>>>> logically
>> >>> >> >> >>>>> "at
>> >>> >> >> >>>>> the
>> >>> >> >> >>>>> same time" (with DUM). I do know that the current code
>> >>> >> >> >>>>> doesn't
>> >>> >> >> >>>>> allow
>> >>> >> >> >>>>> for
>> >>> >> >> >>>>> real parallel NIT requests (i.e. the NIT queue in
>> >>> >> >> >>>>> InviteSession)
>> >>> >> >> >>>>> -
>> >>> >> >> >>>>> but
>> >>> >> >> >>>>> that's not my issue.
>> >>> >> >> >>>>> The issue I have is regarding how to match incoming INFO
>> >>> >> >> >>>>> responses
>> >>> >> >> >>>>> to
>> >>> >> >> >>>>> their request. Imagine I need to send INFO messages
>> regarding
>> >>> >> >> >>>>> application-specific transactions (like DB transactions or
>> >>> >> >> >>>>> whatever
>> >>> >> >> >>>>> application specific thing like a button click). I'll call
>> >>> >> >> >>>>> those
>> >>> >> >> >>>>> non-SIP
>> >>> >> >> >>>>> transaction ids "keys".
>> >>> >> >> >>>>> If I can't have the keys passed into the INFO body and
>> then
>> >>> >> >> >>>>> have
>> >>> >> >> >>>>> them
>> >>> >> >> >>>>> resupplied back into the INFO response, there is no easy
>> way
>> >>> >> >> >>>>> of
>> >>> >> >> >>>>> matching
>> >>> >> >> >>>>> which response is for which request (especially if my
>> >>> >> >> >>>>> application
>> >>> >> >> >>>>> would
>> >>> >> >> >>>>> allow multiple requests to be sent (queued in NIT queue)
>> at
>> >>> >> >> >>>>> the
>> >>> >> >> >>>>> same
>> >>> >> >> >>>>> time).
>> >>> >> >> >>>>> The "workaround" would be to leverage the fact that NITs
>> in
>> >>> >> >> >>>>> an
>> >>> >> >> >>>>> INVITE
>> >>> >> >> >>>>> dialog are all serialized: I could keep a separate list of
>> >>> >> >> >>>>> "keys".
>> >>> >> >> >>>>> If I were
>> >>> >> >> >>>>> to add my key to the list right before sending the INFO
>> >>> >> >> >>>>> message,
>> >>> >> >> >>>>> I
>> >>> >> >> >>>>> would
>> >>> >> >> >>>>> then know that the next INFO response will relate to that
>> key
>> >>> >> >> >>>>> (oldest
>> >>> >> >> >>>>> element of the key list). But this can get messy since I
>> >>> >> >> >>>>> would
>> >>> >> >> >>>>> need
>> >>> >> >> >>>>> to make
>> >>> >> >> >>>>> sure that the "key list" is properly managed.
>> >>> >> >> >>>>
>> >>> >> >> >>>> [Scott]  This solution works without having to modify DUM,
>> and
>> >>> >> >> >>>> its
>> >>> >> >> >>>> likely very similar to how it would be implemented in DUM
>> if
>> >>> >> >> >>>> we
>> >>> >> >> >>>> added
>> >>> >> >> >>>> some
>> >>> >> >> >>>> kind of key/id to the info() call and response callback.
>> >>> >> >> >>>>  Alternatively, you
>> >>> >> >> >>>> could track the transaction id's as the INFO messages flow
>> out
>> >>> >> >> >>>> of
>> >>> >> >> >>>> the
>> >>> >> >> >>>> invite
>> >>> >> >> >>>> session by watching the onReadyToSend callback, but I don't
>> >>> >> >> >>>> think
>> >>> >> >> >>>> that
>> >>> >> >> >>>> offers any advantage over assuming the requests are
>> >>> >> >> >>>> serialized.
>> >>> >> >> >>>>
>> >>> >> >> >>>>>
>> >>> >> >> >>>>> If I look at the similar scenario but with INVITE
>> messages,
>> >>> >> >> >>>>> one
>> >>> >> >> >>>>> can
>> >>> >> >> >>>>> easily leverage the AppDialogSet/... to do this: set the
>> >>> >> >> >>>>> "key" on
>> >>> >> >> >>>>> the
>> >>> >> >> >>>>> AppDialogSet and then it will be easily accessible once
>> >>> >> >> >>>>> INVITE
>> >>> >> >> >>>>> responses
>> >>> >> >> >>>>> arrive (extracted from the INVITE session).
>> >>> >> >> >>>>> I was thinking of extracting the id of the SIP transaction
>> >>> >> >> >>>>> created
>> >>> >> >> >>>>> for
>> >>> >> >> >>>>> the INFO to use it for a lookup between the SIP
>> transaction
>> >>> >> >> >>>>> id
>> >>> >> >> >>>>> and
>> >>> >> >> >>>>> my "key".
>> >>> >> >> >>>>> That way, when handling onInfo* callbacks I would be able
>> to
>> >>> >> >> >>>>> access
>> >>> >> >> >>>>> the SIP
>> >>> >> >> >>>>> transaction id from the response message and map it with
>> my
>> >>> >> >> >>>>> "key".
>> >>> >> >> >>>>> However, this might not be feasible if the SIP transaction
>> id
>> >>> >> >> >>>>> is
>> >>> >> >> >>>>> unknown to the DUM at this time (prior to sending it).
>> >>> >> >> >>>>> What do you make out of this?
>> >>> >> >> >>>>> I suspect this will get worst if reSIProcate ever allows
>> >>> >> >> >>>>> multiple
>> >>> >> >> >>>>> NITs
>> >>> >> >> >>>>> in parallel at the same time (in an INVITE dialog), since
>> >>> >> >> >>>>> then
>> >>> >> >> >>>>> there
>> >>> >> >> >>>>> would
>> >>> >> >> >>>>> really be no easy way of matching them up to application
>> >>> >> >> >>>>> specific
>> >>> >> >> >>>>> data (or
>> >>> >> >> >>>>> am I asking for an AppTransaction class ;)?)
>> >>> >> >> >>>>
>> >>> >> >> >>>> [Scott] Not sure we would ever allow this - I remember this
>> >>> >> >> >>>> being
>> >>> >> >> >>>> discouraged by the IETF.
>> >>> >> >> >>>>
>> >>> >> >> >>>>>
>> >>> >> >> >>>>> Thanks a lot,
>> >>> >> >> >>>>> Francis
>> >>> >> >> >>>>> _______________________________________________
>> >>> >> >> >>>>> resiprocate-devel mailing list
>> >>> >> >> >>>>> resiprocate-devel at resiprocate.org
>> >>> >> >> >>>>>
>> >>> >> >> >>>>>
>> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel
>> >>> >> >> >>>>
>> >>> >> >> >>>
>> >>> >> >> >>
>> >>> >> >> >
>> >>> >> >> >
>> >>> >> >> > _______________________________________________
>> >>> >> >> > resiprocate-devel mailing list
>> >>> >> >> > resiprocate-devel at resiprocate.org
>> >>> >> >> >
>> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel
>> >>> >> >> >
>> >>> >> >
>> >>> >> >
>> >>> >>
>> >>> >> _______________________________________________
>> >>> >> resiprocate-devel mailing list
>> >>> >> resiprocate-devel at resiprocate.org
>> >>> >> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel
>> >>> >
>> >>> >
>> >>>
>> >>> _______________________________________________
>> >>> resiprocate-devel mailing list
>> >>> resiprocate-devel at resiprocate.org
>> >>> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel
>> >>
>> >>
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>> >
>> >
>>
>
>
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