[OpenSIPS-Users] OpenSIPS 'ignoring' incoming '200 OKs' in the middle of a call

[Bogdan-Andrei Iancu]

Hello Jock,

According to the "Bad" debug output, OpenSIPS does not receive the 200 
OK reply at all. As you can see, starting with line 52, the incoming 100 
Trying is handled by process 24205, up to line 94 (time 08:41:53). AFter 
that silence, nothing is received until 08:42:25 when a BYE is received.

Maybe the 200 OK are discarded by OS (in terms of not be delivered to 
the application level) as the UDP packet is too large and fragmented 
(and some fragments are missing) ?? have you checked with a pcap to see 
if the 200 OK is fragmented ?

Best regards,

Bogdan-Andrei Iancu
   OpenSIPS Founder and Developer
   http://www.opensips-solutions.com

OpenSIPS Summit May 2017 Amsterdam
   http://www.opensips.org/events/Summit-2017Amsterdam.html

On 03/27/2017 05:56 PM, Jock McKechnie wrote:
> Greetings all;
>
> This is in continuation with a message I sent last week ('OpenSIPS
> debug logging SIP packets it deems non-local'). I've been beating my
> head against this problem for almost three weeks now and I'm really
> hoping someone might be able to offer some insight. Either the problem
> is really, really stupid - or it's seriously nasty.. and unfortunately
> I'm just not grokking this one.
>
> I have a "good" call flow and a "bad" call flow. The "good" one looks
> like the below:
> SIP Call Source (pjsip) -> LoadBalancer (OpenSIPS) -> Destination (FreeSWITCH)
>
> The bad one:
> SIP Call Source (pjsip) -> Proxy (OpenSIPS) -> LoadBalancer (OpenSIPS)
> -> Destination (FreeSWITCH)
>
> In both flows above the Source, LoadBalancer and Destination servers
> are the same machines, the only change is the addition of a Proxy
> between the Source and the LoadBalancer. In the former call flow
> everything works exactly as expected - the call originates, makes it
> through the LoadBalancer and gets passed onto the Destination, and all
> returning messages are routed as expected, the call comes up, the call
> tears down, life is good.
>
> When the middleman Proxy is added all of a sudden the LoadBalancer
> stops seeing 200 OKs from the Destination box. The LoadBalancer DOES
> see 100 Tryings, so it's not completely busted, but it ignores/doesn't
> receive/something the 200 OKs. And I just cannot figure out why it's
> decided it can't see these.
>
> I've compared both traps and signaling fields and besides an
> additional Via (the Proxy) and tag differences, they appear identical
> to my eyes. I've verified it's not local firewall (if it was the
> OpenSIPS shouldn't have seen the 100 Trying either, but I've also
> totally dropped the fw to no avail), the messaging is all following
> the same networking path, it's coming in on the correct interface on
> the LoadBalancer, the obvious in other words.
>
> I've simplified the LoadBalancer config to the point it's not
> "balancing" and is just sending to a specific FreeSWITCH box and the
> behaviour is consistent. I've tried this on three versions of OpenSIPS
> - 1.8.5, 1.8.8 and 1.11.6 and the behaviour is also consistent across
> versions.
>
> I have a bunch of traps and debug in the hopes someone might spot
> something. These are all coming from a 1.8.5 release of OpenSIPS, for
> what it's worth, although given it's across multiple versions
> (including LTS), I'm guessing the version does not have anything to do
> with it.
>
> The opensips config I'm using is:
> https://pastebin.com/LPNHtrVC
>
> The "Good" ngrep trace:
> https://pastebin.com/y8Way7Vq
>
> The "Good" level 9 debug output:
> https://pastebin.com/pwJvdafp
>
>
> The "Bad" ngrep trace where you can see it ignoring the 200 OKs:
> https://pastebin.com/9b322irb
>
> The "Bad" debug output:
> https://pastebin.com/MVdWDEgx
>
>
> I've replaced the IPs in our flow with bogus hostnames to (hopefully)
> illustrate things clearly - using hostnames, the call flow looks like:
> Source.Me.com -> (Proxy.Me.com) -> LoadBalancer.Me.com -> Destination.Me.com
>
> The destination number, 8005000300, is a test number on our platform -
> although it is (presumably) a real US number, we're not routing this
> out into the "Wild". The source is similarly a bogus number for
> testing purposes.
>
> If anyone has any suggestions, theories or insights, I cannot describe
> to you how grateful I would be to hear them. By necessity I have to
> add this additional Proxy into the call flow, so I -need- to make this
> work.
>
> As always, my thanks,
>   - Jock
>
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