Hi Bogdan, so the problem we are facing is the endpoint has a new branch however the difference in the branch value is AFTER the MAX_BRANCH_PARAM_LEN, the highlighted text. Since opensips is copying the partial branch which is same as the previous Via and thus our SIP stack (OCCAS) is sending back 401 Unauthorized for both thinking it's a retransmit.
This is also in line with RFC3261. Shouldn't it copy the entire Via to make sure it's different from previous Message ?
REGISTER 1
Via: SIP/2.0/UDP 10.204.70.156:5060;branch=z9hG4bK1c68e33e-848e-412a-9137-4fb065a7b7eb_0efbfc5e_11391
Via: SIP/2.0/UDP 10.205.236.44:5060;branch=z9hG4bK1c68e33e-848e-412a-9137-4fb065a7b7eb_0efbfc5e_113915620064228_MTAuMTIuMy4xMQ
REGISTER 2
Via: SIP/2.0/UDP 10.204.70.156:5060;branch=z9hG4bK1c68e33e-848e-412a-9137-4fb065a7b7eb_0efbfc5e_11391
Via: SIP/2.0/UDP 10.205.236.44:5060;branch=z9hG4bK1c68e33e-848e-412a-9137-4fb065a7b7eb_0efbfc5e_113915656050004_MTAuMTIuMy4xMQ
Thanks
Rahul Gupta
Systems Architect
T +1 732-690-3845 * E rahul.gupta at ipc.com<mailto:rahul.gupta at ipc.com>
[cid:image006.jpg at 01D1940F.3E021840]
From: Bogdan-Andrei Iancu [mailto:bogdan at opensips.org]
Sent: Thursday, July 07, 2016 4:43 AM
To: Gupta, Rahul
Cc: Elliott, Ray; users at lists.opensips.org
Subject: Re: [OpenSIPS-Users] Truncated Branch in Via
Hi Rahul,
The received VIA hdr (with the .44 IP) is properly preserved when forwarding (in the outbound message).
The VIA hdr added by OpenSIPS ( .156 IP) is a completely new VIA and its branch value is completely independent from the branch of other VIA hdrs.
Why do they look the same ? The RFC3261 says that for stateless fwd (when basically there is no transaction, so no branch value), to avoid populating its VIA with ";branch=0" , the proxy may "copy" and use a branch value from an older VIA (a received VIA) - keep in mind it does not say to copy it entirely or part. So, OpenSIPS copies a MAX_BRANCH_PARAM_LEN length string from the previous branch param.
Everything is correct and legal (from RFC perspective).
PS: if you would use t_relay() instead of forward() - doing statefull proxy -, you will see that the branch in the VIA added by OpenSIPS will be completly different from the value in the previous VIA.
Best regards,
Bogdan-Andrei Iancu
OpenSIPS Founder and Developer
http://www.opensips-solutions.com
On 07.07.2016 03:42, Gupta, Rahul wrote:
Hi Bogdan,
Here is a Ethernet trace (pcap) file that has a successful and an unsuccessful registration.
Frames 1-8 illustrate the successful case with Frames 2 and 6 show how opensips adds an extra VIA header that has a full VIA;branch
Frame:2
Via: SIP/2.0/UDP 10.204.70.156:5060;branch=z9hG4bK-c45d6-2ff0ce63-4583dc45-6bd144f8
Via: SIP/2.0/UDP 10.204.45.122:5060;branch=z9hG4bK-c45d6-2ff0ce63-4583dc45-6bd144f8
Frames 9-16 illustrate the unsuccessful case where Frames 10 and 14 show how opensips adds an extra VIA header that has a truncated branch.
Frame 10:
Via: SIP/2.0/UDP 10.204.70.156:5060;branch=z9hG4bK1c68e33e-848e-412a-9137-4fb065a7b7eb_0efbfc5e_11391
Via: SIP/2.0/UDP 10.205.236.44:5060;branch=z9hG4bK1c68e33e-848e-412a-9137-4fb065a7b7eb_0efbfc5e_113915620064228_MTAuMTIuMy4xMQ
Thanks
Rahul Gupta
Systems Architect
T +1 732-690-3845 * E rahul.gupta at ipc.com<mailto:rahul.gupta at ipc.com>
[cid:image006.jpg at 01D1940F.3E021840]
From: Bogdan-Andrei Iancu [mailto:bogdan at opensips.org]
Sent: Wednesday, July 06, 2016 5:38 AM
To: OpenSIPS users mailling list
Cc: Elliott, Ray; Gupta, Rahul
Subject: Re: [OpenSIPS-Users] Truncated Branch in Via
Hi Rahul,
That define is used to calculate the the max VIA len when OpenSIPS is generating its own VIA headers. That max len does not impact the VIA headers which were received.
I do not understand exactly (in your example) what's the flow of that VIA header. If you want, send me off-list the pcap/ngrep showing the SIP package (before and after OpenSIPS) and how it is affected.
Regards,
Bogdan-Andrei Iancu
OpenSIPS Founder and Developer
http://www.opensips-solutions.com
On 05.07.2016 20:57, Gupta, Rahul wrote:
We are using opensips 1.11.5 as a stateless proxy and seeing a truncated Branch in Via for my REGISTER message. After some code digging, the MAX length is calculated using the following formula and seems like its truncating the branch after 55 characters. This is causing the REGISTER to fail in our case. Is there a config level solution to this ?
#define MAX_BRANCH_PARAM_LEN (MCOOKIE_LEN+8 /*!<int2hex*/ + 1 /*sep*/ + \
MD5_LEN + 1 /*!<sep*/ + 8 /*int2hex*/ + \
1 /*extra space, needed by t_calc_branch*/)
truncated from opensips --> Via: SIP/2.0/UDP XX.XX.XX.XX:5060;branch=z9hG4bK0fddbbc9-1487-4755-a0b3-0c319155b8c3_0efbfc5e_11160
Via from EndPoint --> Via: SIP/2.0/UDP XX.XX.XX.XX:5060;branch=z9hG4bK0fddbbc9-1487-4755-a0b3-0c319155b8c3_0efbfc5e_1116078308924346_MTAuMTIuMy4xMQ
Thanks
Rahul Gupta
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