Hi Alexander.
The problem here is not related to the ability or inability of OpenSIPS
to drop the late 200 OK - the problem is you MUST not drop it, as you
will break the signaling. Again, a callee party sending a 200 OK expects
an ACK and nothing else.
If you drop (on OpenSIPS level) the late 200 OK, the vendor 1 will
remain inconsistent - it will keep retransmitting the 200 OK as it
expected the ACK for it.
Of course, there is the ugly approach of "playing dead", dropping every
single late 200 OK from Vendor 1, forcing it to generate a BYE
(eventually) and close the call. But this is something really ugly.
Regards,
Bogdan-Andrei Iancu
OpenSIPS Founder and Developer
https://www.opensips-solutions.com
https://www.siphub.com
On 6/28/23 10:13 AM, Alexander Kogan wrote:
Hi,
I got the point. Nevertheless, isn't it a good idea to have a way to
discard messages of branches that have already been timed out instead
of reanimating them? E.g. t_check() could return -2 in
reply_received(), or drop() action could be allowed for 200...
Best regards,
Alexander Kogan,
Director of R&D
5g Future
http://5gfuture.com
On 28.06.2023 10:37, Bogdan-Andrei Iancu wrote:
Hi Alexander,
According to RFC3261, there is noting a proxy should/must do about a
received 200 OK rather than sending further to the caller (even if
the 200 OK is received on an old branch). Basically, if for whatever
reasons you end up getting 200 OK from several branches of the same
transaction, you need to forward them all to caller - why? as in SIP,
once a 200 OK was fired by a callee device, there is no signaling
/mechanism available to "cancel"/"reject"/"discard" that it. The only
way to handle "unwanted" 200 OK is to accept it, ack it and then
send a BYE for it.
Now, as a proxy does not have the necessary "logic" to decide which
200 OK to keep and which to BYE, there is nothing to be done than
"moving" this decision to the caller - so pass all the 200 OK to
caller and let it decide which to keep or not.
Regards,
Bogdan-Andrei Iancu
OpenSIPS Founder and Developer
https://www.opensips-solutions.com
https://www.siphub.com
On 6/27/23 5:59 PM, Alexander Kogan wrote:
Hello,
I've got such a call flow:
Client OpenSIPS
|--INVITE-->|
|<--100-----| Vendor1
| |--INVITE-->|
| |--INVITE-->|
| |--INVITE-->|
| | | Vendor2
| |--INVITE------------- >|
| |<--100-----------------|
| |<--180-----------------|
|<--180-----| |
| |<--200-----------------|
|<--200-----| |
| | |
| |<--200-----| |
|<--200-----| |
| | | |
The first branch was timed out and we switched up to the next one. A
bit later we received 200 OK from the first one. The question is -
how to avoid passing 200 to the first leg? drop() doesn't work for
final responses. I also can't use t_cancel_branches() because it
works in onreply_route only which is not called in case of timeout....
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