[OpenSIPS-Users] tcp_async timeouts confusion

[Steve Brisson]

Sorry for the late response.

Unfortunately I no longer have call access to the vcs server that experienced this error and the issue seemed timing dependent on that particular call path. I will update the bug with DBG logs if I am able to recreate the problem by some other means.

Thanks for the help.

From: Users [mailto:users-bounces at lists.opensips.org] On Behalf Of Liviu Chircu
Sent: Friday, January 19, 2018 7:16 AM
To: users at lists.opensips.org
Subject: Re: [OpenSIPS-Users] tcp_async timeouts confusion


Hi Steve,

I've opened a GitHub issue for this report so we can better keep track of it [1], and will likely be next on my priority list. I will try to find some time to attempt to reproduce it asap. In the meanwhile, would you be as kind as to supply some debug logs while the async TCP reads are piling up? You may ship them to liviu at opensips.org<mailto:liviu at opensips.org>.

Best regards,

[1]: https://github.com/OpenSIPS/opensips/issues/1259

Liviu Chircu

OpenSIPS Developer

http://www.opensips-solutions.com
On 18.01.2018 18:35, Steve Brisson wrote:
Hi, just wondering if this issue is still being considered.

Thanks,
steve

From: Users [mailto:users-bounces at lists.opensips.org] On Behalf Of Steve Brisson
Sent: Thursday, January 11, 2018 11:56 AM
To: OpenSIPS users mailling list <users at lists.opensips.org><mailto:users at lists.opensips.org>
Subject: Re: [OpenSIPS-Users] tcp_async timeouts confusion

TCP scenario:
Yes that is exactly correct. If I have tcp_connect_timeout=3000 and tcp_async=1 configured then calls to the vcs fail. If I then make the single change to disable tcp_async, calls to my vcs endpoints will work.

TLS scenario:
Thanks for the clarification, makes sense. Unfortunately the online documentation doesn't describe the parameters and lists an incorrect scaling factor (it's defined in milliseconds, not seconds).

steve

From: Users [mailto:users-bounces at lists.opensips.org] On Behalf Of Liviu Chircu
Sent: Thursday, January 11, 2018 3:39 AM
To: users at lists.opensips.org<mailto:users at lists.opensips.org>
Subject: Re: [OpenSIPS-Users] tcp_async timeouts confusion


Answers below,


On 09.01.2018 22:25, Steve Brisson wrote:

*** Using TCP ***

After the invite is sent to the vcs, tcpdump at the opensips server showed 100, 180, and 200 OK responses from the vcs arriving and ACK'd correctly at the opensips server. The 100 response arrived 185ms after the invite is sent. But, I don't see these responses in the branch's onreply_route, the global onreply_route, or in the log at DBG level. netstat -t shows the connection with the data in the recv-q that never reaches 0. This implies to me that opensips is not polling that connection correctly for recv data.

If I disable tcp_async then the call is completed successfully. So in the case that works, I have tcp_connect_timeout=3000 and tcp_async=0.
Just to confirm the scenario: So the signaling is broken with "tcp_connect_timeout=3000 and tcp_async=1" (reply routes do not get triggered / recv-q keeps on growing), however once you switch to "tcp_async=0", everything is back to working?

*** Using TLS ***

Running tcpdump, I see the opensips server send a Client Hello then a FIN packet 100ms later. The vcs responds with a Server Hello 200ms after the Client Hello and this gets RST.

To workaround this case, I set tls_handshake_timeout=3000 and tls_send_timeout=1000. Maybe this is the correct behavior, I'm still not 100% sure how the tls parameters function.
This time, it's behaving as expected. Maybe there should be a diagram somewhere with how these parameters work together. For example, each TLS connection will roughly follow the below steps along with their corresponding parameterized timeouts:

1. TCP connect (tcp_connect_timeout)
2. TLS connect/accept handshake (tls_handshake_timeout)
3. TLS write (tls_send_timeout)
4. TLS write (tls_send_timeout)



Liviu Chircu

OpenSIPS Developer

http://www.opensips-solutions.com




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