[asterisk-dev] Problem with SDP session id in 200 OK during ReInvite

[Michael Maier]

Hello Joshua,


On 27.10.20 at 10:07 Joshua C. Colp wrote:
> On Mon, Oct 26, 2020 at 2:02 PM Michael Maier <m1278468 at mailbox.org> wrote:
> 
>> Hello!
>>
>> I'm facing the problem, that *sometimes* the SDP session ID isn't
>> incremented in the 200 OK, which asterisk sends as answer to a ReInvite it
>> got from the peer (use case: session
>> timer handling). This leads to broken calls, because the SDP session ID
>> must be incremented if the session description has changed (the session
>> description has changed).
>>
>> Modifying the SDP session ID is possible in
>> res/res_pjsip/pjsip_message_filter.c / filter_on_tx_message() for SDPs
>> contained in an Invite, which is created and sent by asterisk.
>> At the moment, I'm already modifying the SDP session ID at this place,
>> because of another problem:
>>
> 
> <snip>
> 
> 
>> Maybe it's too late and the processing of the 200 OK doesn't hit this part
>> at all?
>>
>> Or is there any other possibility to modify the SDP session ID contained
>> in the 200 OK, that is sent by asterisk as an answer to a ReInvite?
>>
> 
> It should be modifiable there, it injects itself at the transaction layer
> to be called for both requests and responses. I'm not sure under what
> scenarios (if any) it would not be called.

thanks for your estimation! Meanwhile, I hope I have found the problem now. I changed my workaround to always statically modify the SDP session id (the condition seemed to be the
problem). But tests are going on.


Thanks
Michael