[reSIProcate] exception when receiving 200 from re-invite requestwith modified to: tag

[Justin Matthews]

I didn't see the BaseCreator last request being updated, so I'm not sure
where to find the cseq for this re-invite.  

In looking at sending the re-invite the only info I could see being updated
is: mRequests[msg->header(h_CSeq).sequence()] = msg; in Dialog::send. The
problem with this is that the UAS has modified the tag so dum can't find any
existing dialog, so the cseq of the initial re-invite request will need to
be stored somewhere at the dialogset level?   What about adding the cseq
info to mLastRequest in the BaseCreator when sending the initial re-INVITE?


 

Thanks,

 

-justin

 

  _____  

From: Scott Godin [mailto:slgodin at icescape.com] 
Sent: Monday, December 11, 2006 10:30 AM
To: Justin Matthews; resiprocate-devel at list.sipfoundry.org
Subject: RE: [reSIProcate] exception when receiving 200 from re-invite
requestwith modified to: tag

 

I don't think this is quite right - it will not allow multiple 200's to an
initially forked invite request to create dialogs.

 

I think we should check the CSeq in response and only create a dialog if it
matches the CSeq in the base creator.  This will make sure we only create
multiple dialogs for an initial UAC request, but not mid dialog requests.

 

Scott

 

From: Justin Matthews [mailto:jmatthewsr at gmail.com] 
Sent: Monday, December 11, 2006 10:24 AM
To: Scott Godin; resiprocate-devel at list.sipfoundry.org
Subject: RE: [reSIProcate] exception when receiving 200 from re-invite
requestwith modified to: tag

 

Further on this issue, although the patch fixes the exception and drops the
200 for the case where dum was initially the UAS, this scenario will still
cause issues if dum was initially the UAC (since getLastRequest will contain
a valid contact).

 

Propose the following, please note that I am not sure that "mState ==
Established" is the correct check here, please advise.

 

In DialogSet.cxx:

 

if (dialog == 0)

   {

      if (msg.isRequest() && msg.header(h_RequestLine).method() == CANCEL)

      {

         dispatchToAllDialogs(msg);

         return;

      }

 

      if (msg.isResponse())

      {                     

         int code = msg.header(h_StatusLine).statusCode();

         

             if( code > 100 && mState == Established )

             {

                InfoLog(<< "Cannot create a dialog, mid-dialog fork not
allowed.");

                return;

             }

 

 

Thanks,

 

-justin

 

  _____  

From: Scott Godin [mailto:slgodin at icescape.com] 
Sent: Sunday, December 10, 2006 10:50 AM
To: Justin Matthews; resiprocate-devel at list.sipfoundry.org
Subject: RE: [reSIProcate] exception when receiving 200 from re-invite
requestwith modified to: tag

 

That is pretty odd behaviour by the far end.  Mid-dialog forking is not
allowed (3261 sec 14.1).  If we detect a 200 with a different to tag and the
dialogset is a UAS dialogset (ie. no base creator) - then we should either:

1.  Ack the 200 and then send a bye.    or

2.  Just ignore the 200 - don't proceed to create a dialog for it - but log
an error.

 

I'm leaning towards 2.

 

Scott

 

  _____  

From: resiprocate-devel-bounces at list.resiprocate.org on behalf of Justin
Matthews
Sent: Sat 12/9/2006 5:26 PM
To: resiprocate-devel at list.sipfoundry.org
Subject: [reSIProcate] exception when receiving 200 from re-invite
requestwith modified to: tag

Exception occurs during following scenario:

 

DUM receives a call and establishes a session as the UAS.

 

DUM sends re-INVITE request

 

DUM receives 200 ok response with a different to: tag then the established
session.

 

The dialogset is found, but dialogset.cxx tries to create a new dialog from
this 200 and calls the following code:

 

Dialog.cxx, in Dialog constructor:

 

mLocalContact = creator->getLastRequest()->header(h_Contacts).front();

 

I believe that getLastRequest does not contain a contact because this call
was established from an inbound session.

 

For now I just patched it this way, is there a better way?  If not I will
commit this. 

-------------------

BaseCreator* creator = mDialogSet.getCreator();

//assert(creator);// !jf! throw or something here

//assert(creator->getLastRequest()->exists(h_Contacts));

//assert(!creator->getLastRequest()->header(h_Contacts).empty());

if( NULL == creator )

{

ErrLog(<< "BaseCreator is null for DialogSet");

      ErrLog(<< response);

      throw Exception("BaseCreator is null for DialogSet", __FILE__,
__LINE__);

}

                               

SharedPtr<SipMessage> lastRequest(creator->getLastRequest());

 

if( NULL == lastRequest ||

      !lastRequest->exists(h_Contacts) ||

      lastRequest->header(h_Contacts).empty())

{

      ErrLog(<< "No contact available for dialogset's last request");

      ErrLog(<< response);

      throw Exception("No contact available for dialogset's last request",
__FILE__, __LINE__);

}

mLocalContact = creator->getLastRequest()->header(h_Contacts).front();

mRemoteTarget = contact;

----------------------

 

Thanks,

-justin

 

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