[OpenSIPS-Users] B2BUA, authenticated INVITEs with "ACK for a negative reply"

[Răzvan Crainea]

On 11/29/2016 04:09 AM, Nathan Ward wrote:
>> On 29/11/2016, at 5:25 AM, Răzvan Crainea <razvan at opensips.org> wrote:
>>
>> Hi, Nathan!
>>
>> Have you tried calling b2b_init_request() with the "a" flag [1]?
>>
>> [1] http://www.opensips.org/html/docs/modules/2.2.x/b2b_logic.html#id294010
> Hi,
>
> Yes I have. This passes through the authentication challenge headers in the 401/407, and then any subsequent response headers in the new INVITE.
>
> b2b_logic/logic.c:1239 calls b2b_mark_todel, after forwarding the message - because it is marked to_del, the ACK that the originator of the INVITE sends in response to the 401/407 deletes the session.
>
> I don’t understand how this flag is intended to be used, as there doesn’t seem to be anything in the code to avoid setting to_del if the response is a 401/407 (or anything >=300, actually) with auth challenge headers. All it does is pass through the headers, but as it deletes the session, a new Call-ID is issued by B2BUA when the authenticated invite is generated.
>
Hi, Nathan!

Yes, you are right, the flag simply passes the auth headers between the 
two legs.
So you were saying that you were only using b2b for topology hiding? If 
so, why not using directly the topology_hiding module[1]?

[1] http://www.opensips.org/html/docs/modules/2.2.x/topology_hiding.html

Best regards,

Răzvan Crainea
OpenSIPS Solutions
www.opensips-solutions.com