[OpenSIPS-Users] remove_hf doesn't seem to work in route[b2b_reply]

[Bogdan-Andrei Iancu]

Hi Louis,

The b2b_reply route is invoked for int incoming reply. This reply is 
internally consumed and another one is generated on the other side of 
the B2B (basically there are two back 2 back transactions).

The new reply (on A side) is built based on information from the 
incoming reply (on B side) - considering that the original INVITE went 
from A to B.

So, any change you do on incoming rely will be discards because a new 
reply is to be built on the other side. Headers (as a whole) may 
propagate via "custom_headers" parameters. Otherwise, whatever 
append_hf() you do in b2b_reply will be lost (not translated to the 
other side).

Even more, the Contact has a special treatment as it is completely 
rebuilt by the B2B - old Contact hdr is discarded and a new one 
(pointing to B2B) is added in the outbound reply. So your changes over 
the incoming contact do conflict with the changed the B2B module does 
over the contact.

In my test, having "contact" in the "custom_headers" and doing 
remove_hf()+append_hf() on a contact on b2b_reply, results in two 
Contact headers :
     - the one removed, added and carried via custom header (from the 
incoming reply)
     - the one built and added internally by the B2B, pointing to it self

So, remove_hf() actually works, but you end up with that conflict in 
having you and the B2B changing both the Contact hdr.

As I understand, your goal is to preserve the username part in B2B right ?

Best regards,

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

On 15.10.2015 21:40, Louis Rochon wrote:
>
> remove_hf doesn't seem to work in route[b2b_reply]….Running OpenSIPS 
> 1.11.5 on CentOS 6.
>
> This problem started when I discovered that b2b_init_requests removes 
> the user part of the URI in the Contact: field.
>
> To correct that, did a bit of scripting to correct the outgoing invite:
>
> First, handle contacts manually:
>
> modparam("b2b_logic", "custom_headers", 
> "Priority;Calluid;Geolocation;Geolocation-Routing;Contact")
>
> Second, check out the incoming INVITE, and modify the host part to be 
> the OpenSIPs server itself (192.168.130.105):
>
> $var(ContactURI)=$ct.fields(uri);
>
> $var(ContactURIHost)=$(var(ContactURI){uri.host});
>
> $var(ContactURIUser)=$(var(ContactURI){uri.user});
>
> $var(regedit)="/"+$(var(ContactURIHost))+"/192.168.130.105/g";
>
> $var(URIwSub)=$(var(ContactURI){re.subst,$var(regedit)});
>
> Third, in local_route, remove the incoming contact and replace with my 
> own:
>
> remove_hf("Contact");
>
> append_hf("Contact: $var(URIwSub)\r\n");
>
> Fourth, send off the invite downstream (to 192.168.131.203):
>
> b2b_init_request("FailOver", "sip:$tU at 192.168.131.203");
>
> All this works! Great, but the reply route, not:
>
> route[b2b_reply] {
>
>         xlog("b2b_reply Route ($ci)\n");
>
> ###Debug Code
>
> xlog(">>>>>B2BRR:Protocol of received message: $pr\n");
>
> xlog(">>>>>B2BRR:Body of request/reply: $rb\n");
>
> xlog(">>>>>B2BRR:Return Code: $rc\n");
>
> xlog(">>>>>B2BRR:Request Method: $rm\n");
>
> xlog(">>>>>B2BRR:Reply Reason: $rr\n");
>
> xlog(">>>>>B2BRR:Reply Status: $rs\n");
>
> xlog(">>>>>B2BRR:Transport protocol of original R-URI: $oP\n");
>
> xlog(">>>>>B2BRR:Transport protocol of R-URI: $rP\n");
>
> xlog(">>>>>B2BRR:Transport protocol of destination uri: $dP\n");
>
> xlog(">>>>>B2BRR:Destination set: $ds\n");
>
> xlog(">>>>>B2BRR:Destination uri: $du\n");
>
> xlog(">>>>>B2BRR:URI of From header: $fu\n");
>
> xlog(">>>>>B2BRR:Domain in request's original R-URI: $od\n");
>
> xlog(">>>>>B2BRR:Request's original URI: $ou\n");
>
> xlog(">>>>>B2BRR:Username in request's original URI: $oU\n");
>
> xlog(">>>>>B2BRR:Domain in URI of 'To' header: $td\n");
>
> xlog(">>>>>B2BRR:Complete Request URI: $ru\n");
>
> xlog(">>>>>B2BRR:Username in Request URI: $rU\n");
>
> xlog(">>>>>B2BRR:Username in URI of 'To' header: $tU\n");
>
> xlog(">>>>>B2BRR:Surname in URI of 'From' header : $fU\n");
>
> xlog(">>>>>B2BRR:Contact name:$ct.fields(name)\n");
>
> xlog(">>>>>B2BRR:Contact uri:$ct.fields(uri)\n");
>
> xlog(">>>>>B2BRR:Contact q param:$ct.fields(q)\n");
>
> xlog(">>>>>B2BRR:Contact expires:$ct.fields(expires)\n");
>
> xlog(">>>>>B2BRR:Contact methods:$ct.fields(methods)\n");
>
> xlog(">>>>>B2BRR:Contact params:$ct.fields(params)\n");
>
> $var(ContactURIRR)=$ct.fields(uri);
>
> $var(ContactURIHostRR)=$(var(ContactURIRR){uri.host});
>
> $var(regeditRR)="/"+$(var(ContactURIHostRR))+"/192.168.130.105/g";
>
> $var(URIwSubRR)=$(var(ContactURIRR){re.subst,$var(regeditRR)});
>
> if(remove_hf("Contact"))
>
> {
>
> xlog(">>>>>B2BRR:removed Contact\n");
>
> } else {
>
> xlog(">>>>>B2BRR:DID NOT removed Contact\n");
>
> };
>
> #
>
> # xlog("Substituted Contact URI Variable Reply Route:$var(URIwSubRR)\n");
>
> append_hf("Contact: $var(URIwSubRR)\r\n");
>
> #replace_body_all("Contact", "BlaBla");
>
> }
>
> So in route[b2b_reply], do the same treatment as in the invite. The 
> xlog says that it did remove the Contact, but it’s still there, 
> according to wireshark. The append_hf works fine, but the remove_hf 
> never works. I end up with 2 Contact.
>
> Any ideas?
>
> *Louis Rochon*
>
> Senior Systems Designer
>
> Solacom Technologies
>
> 819 205 8100 ext. 274
>
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