[SR-Users] Manipulating contacts header results in a malformed SIP packet

[Sergey Safarov]

Looks as not expected here

sip:4.5.6.7:5060;alias=10.100.1.1~5060~1Content-Type: application/sdp

About contact header.
Yes it is really important header.
If your carrier want specific Contact header format, then I recommend try
use other provider.

Contact header used also for RURI headers. So you cannot simple change
Contact.

Kamailio is very good SP proxy. For you will more simple invite Kamailio
tech guy to configure inter-working with this specific carrier.


On Thu, Mar 19, 2020 at 4:43 AM Andrew White <andrew at uconnected.com.au>
wrote:

> Hi all,
>
> Hope everyone is well, and looking forward to seeing you all whenever
> Kamailio World ends up being!
>
> I’m currently dealing with an issue which I’m unsure if it’s due to my own
> implementation, or a bug.
>
> When attempting to manipulate the Contact header via app_ruby, the SIP
> message I send ends up being malformed. Here’s the code I’m using:
>
> def replace_contact_header(uri)
> #KSR::HDR.remove("Contact") if KSR::HDR.is_present('Contact') > 0
> #KSR::HDR.append("Contact: #{uri}\r\n")
> KSR::HDR.rmappend("Contact", "Contact: #{uri}\r\n")
> end
>
> Note that I have tried both rmappend and the commented out functions too.
> I call this with a custom built URI, such as <
> 61400123123 at kamailio.test.uconnected.com.au>. This function is called
> just before a KSR::TM.t_relay(). Here’s the result I get watching from
> tshark (some info scrubbed for privacy):
>
> Record-Route: <
> sip:1.2.3.4;lr;ftag=e3p42efd3635HH;vst=AAAAAAAAAAAAAAAAAAAAAAoUXVFHDQAAs83AEGwAAFgwCQA8QY3RlZC5jb20uYXU-;did=927.f0f2
> >
> …
> Call-ID: 3de29646-e423-1238-e712-023563fb337c
> CSeq: 17736747 INVITE
> sip:4.5.6.7:5060;alias=10.100.1.1~5060~1Content-Type: application/sdp
> Content-Length: 483
> Contact: <sip:61400123123 at kamailio.test.uconnected.com.au>
>
> In this case, 4.5.6.7 is the PBX I made the call from (and the value of
> the original Contact header), and 1.2.3.4 is what
> kamailio.test.uconnected.com.au resolves to, and is this Kamailio
> instance.
>
> Here’s a copy of the same thing when I don’t call my
> replace_contact_header function and t_relay:
>
> Record-Route: <
> sip:1.2.3.4;lr;ftag=j6jebCSa5Qap6c;vst=AAAAAAAAAAAAAAAAAAAAAAoUXVND38dTgwEGEAEGwAAFgwCQA8Fdn83lZC5jb20uYXU-;did=827.40b
> >
> ...
> Call-ID: 249571c5-e91a-ae91-6d8e-023563fb337c
> CSeq: 17735867 INVITE
> Contact: <sip:4.5.6.7:5060;alias=10.100.1.1~5060~1>
> Content-Type: application/sdp
> Content-Length: 483
>
> Given the relative simplicity of the function, I have to assume this is an
> error with how the function is manipulating the existing Contact header? It
> seems that the “Contact: <“ part of the header is being removed as well as
> the “>\r\n", but the rest being left.
>
> I’m currently using commit 283e468401d809ca9b71368c32badf3a70d48b8b
> <https://github.com/kamailio/kamailio/commit/283e46> on Amazon Linux 2,
> which is CentOS/RHEL based.
>
> Thanks!
>
> Andrew
> _______________________________________________
> Kamailio (SER) - Users Mailing List
> sr-users at lists.kamailio.org
> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>
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