[OpenSIPS-Users] nat_traversal: register keepalive not engaging

[Gremaud Odin]

Hi,

I kept on investigating this stuff, and I put openSIPS in a higher debug 
level in order to catch any suspect behavior or whatever. The only thing 
I notice in the log that seems maybe unusual is the following:

DBG:core:forward_reply: found module nat_traversal, passing reply to it
...
DBG:core:parse_params: Parsing params for:[expires=3600]
DBG:core:parse_params: Parsing params 
for:[expires=120;received="sip:1.2.3.4:12345"]
DBG:nat_traversal:get_register_expire: maximum expire for all contacts: 0

 From these debug logs, I can see that the reply (the 200 OK I saw in 
the traces) is handled properly by the nat_traversal module. However, as 
the registrar function is handled by another entity, this maximum expire 
value is never set locally (it is set to 120 on the registrar entity). 
It seems that nat_traversal is not able to get a consistent expiry time, 
the one it gets being 0. Does this means that the keepalive does not 
engage, as nat_traversal believes that the expiry time is set zero ?

Please advise...

Odin


Le 06/09/2011 17:18, odin.gremaud at nexcom.fr a écrit :
> Date: Tue, 06 Sep 2011 15:29:18 +0200
> From: Gremaud Odin<odin.gremaud at nexcom.fr>
> Subject: [OpenSIPS-Users] nat_traversal: register keepalive not
> 	engaging
> To: users at lists.opensips.org
> Message-ID:<4E66202E.1050506 at nexcom.fr>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hello everyone,
>
> I began using the nat_traversal module to create a NAT traversal
> dedicated box, but I'm now stuck on something probably pretty stupid.
> Here is the design I'm working with:
>
> Public network  ||  Private network
>                   ||
>       U1 ------->  P1 ------->  P2
>                   ||
>                   ||
>
> U1 being the NATed UAC, P1 the NAT box and P2 an OpenSIPS Proxy/Registrar.
>
> The registration process is OK, and I can even call another UA using U1.
> When checking the proper functioning of my script, I noticed that I
> could not call U1 from any other UA: indeed, the register keepalive did
> not trigger properly (no keepalive engaged for REGISTER, even if it pass
> on the function). The keepalive mechanism is working fine with INVITE
> (did not try with SUBSCRIBE), I traced OPTION messages going to U1
> (which replies with a "404 Not Found", is this normal?). I
> double-checked using the module statistics, and there was no register
> keepalive, but during an dialog, it effectively shows that U1 is
> keepalived. I traced the registration process for a possible error, but
> the request is correctly transfered to P2, which responds with a 200 OK
> that P1 receives correctly. I have no more ideas about what I'm missing
> here...
>
> If it can help, here is the NAT and registrar process I use:
>
> ### NAT DETECTION ###
> force_rport();
>
> # Avoid NAT detection if source IP is local
> if ( client_nat_test("8")&&  $si!~"^10\.0\.0\.[0-9]{1,3}$") {
>       fix_contact();
>       append_hf("NAT-Scope: nat-relay\r\n");
>
>       # For initial invites and all subscribe
>       if ((is_method("INVITE")&&  !has_totag()) || is_method("SUBSCRIBE")) {
>           nat_keepalive();
>
>       # For registers
>       } else if (is_method("REGISTER")) {
>           nat_keepalive();
>           append_hf("NAT-Received: $source_uri\r\n");
>       }
>
>       setflag(5);
> }
>
> ### REGISTRAR ###
> if (is_domain_local("$fd")&&  is_method("REGISTER")) {
>       append_hf("Supported: Path\r\n");
>       add_path_received();
>       force_send_socket(10.0.0.1:5060);
>       t_relay("10.0.0.2:5060");
>       exit;
> }
>
> ### RELAYING ###
> # The request was processed by the proxy/registrar
> if ($hdr(NAT-Scope)=="nat-relay"&&  !isflagset(5)) {
>       #$du = $hdr(NAT-Received);
>       $fs = $keepalive.socket($du);
> # Not a subsequent message (REGISTER, SUBSCRIBE or initial INVITE),
> avoid looping on P2
> } else if (!has_totag()&&  $si != "10.0.0.2") {
>       $du = "sip:10.0.0.2:5060";
>       $fs = "10.0.0.1:5060";
> }
>
> if (!t_relay("0x03")) {
>       sl_reply_error();
> }
>
> Any advice or idea is welcome :)
>
> Odin
>

Odin