Hello again,

In continuation of this topic, just today I decide to try out nat_keepalive(), it sounded like a nice-to-have feature for my edge proxies.

I can also confirm that when using contact_match=1 && set_contact_alias() the keepalives are being sent out correctly. However, not so much when using fix_nated_contact(). Rightfully so one may argue why use it in 1st place, however in some cases rewriting the Contact's addresses is necessary.

If it's not too much trouble, can the contact_match modparam be adjusted to account for this scenario as well?

Thanks.



On Sat, Apr 4, 2020 at 12:39 PM Daniel W. Graham <dan@cmsinter.net> wrote:
I pulled master branch and tested with contact_match=1 and it resolved the issue. I am using path with loose_route as well, but seems to be an issue with the endpoint not honoring path. I’m going to do further testing later today to make sure it doesn't have negative impact on invite keepalives, but looks good so far.

Thanks for your commits, they are much appreciated! Thanks to all others that offered input as well!


On Apr 4, 2020, at 4:06 AM, Daniel-Constantin Mierla <miconda@gmail.com> wrote:



Hello,

I looked a bit a the code of the nat_traversal module and it takes the Expires values from SIP replies, when REGISTER is forwarded (it has to be with tm t_relay()), but at that moment it compares the contacts with the headers in request (taken from transaction structure) via string comparison and in case of mismatch, they are ignored.

So, when you change the contacts during REGISTER request processing, then you get different values in the replies.

The solution is to not touch the contact at all, but use Path (see path module) when routing out REGISTERs, then call loose_route() for initial requests as well.

An alternative is to try to use the keepalive module instead of nat_traversal, maybe it gives what you need.

And the last one, in master branch I pushed 2 commits (one to core and one to nat_traversal module) to add an option to match the contact URI by comparing type, user, host, port and proto. You can try with master branch by setting contact_match=1 for nat_traversal param and see if works.

Cheers,
Daniel

On 04.04.20 03:05, Daniel W. Graham wrote:

Register time is not detected when add_contact_alias() is enabled:

 

With add_contact_alias() :

 

Apr  3 20:45:01 host /usr/local/sbin/kamailio[28022]: DEBUG: {2 2 REGISTER 103104ZDUxMzk3ZTg4OTM4ZGFhM2M1NmI3ZjBjYTQ3NWM1NWI} nat_traversal [nat_traversal.c:963]: get_register_expire(): maximum expire for all contacts: 0

 

Without add_contact_alias():

Apr  3 20:56:52 edgedev /usr/local/sbin/kamailio[28104]: DEBUG: {2 2 REGISTER 103104ZmRiZTI0Y2NkNjUxNDRiYzg5Njc1MzI1NjRkZTM3MTI} nat_traversal [nat_traversal.c:963]: get_register_expire(): maximum expire for all contacts: 300

-dan

 

From: "miconda@gmail.com" <miconda@gmail.com>
Reply-To: "miconda@gmail.com" <miconda@gmail.com>
Date: Friday, April 3, 2020 at 4:03 PM
To: Daniel Graham <dan@cmsinter.net>, "Kamailio (SER) - Users Mailing List" <sr-users@lists.kamailio.org>
Subject: Re: [SR-Users] nathelper without usrloc

 

OK, so there were some messages I still missed in the middle of the discussion...

Can you get all log messages with debug=3 when the keepalive is attempted to be sent?

Cheers,
Daniel

On 03.04.20 21:51, Daniel W. Graham wrote:

I resolved all of the routing issues. Only issue I’ve got now is nat_keepalive not working when used with set/add_contact_alias().

 

-dan

 

 

From: "miconda@gmail.com" <miconda@gmail.com>
Reply-To: "miconda@gmail.com" <miconda@gmail.com>
Date: Friday, April 3, 2020 at 1:43 PM
To: Daniel Graham <dan@cmsinter.net>, "Kamailio (SER) - Users Mailing List" <sr-users@lists.kamailio.org>
Subject: Re: [SR-Users] nathelper without usrloc

 

Somehow I thought that the keepalive is not working and you look for fixing it. Now I read the full thread and actually the routing of requests within dialog doesn't work.

Can you send a pcap with such a call taken on Kamailio system? ACK and BYE should be routed based on Contact of INVITE/200ok and record-route headers, no longer related to REGISTER (only initial INVITE should rely on registration data).

Cheers,
Daniel

On 02.04.20 22:11, Daniel W. Graham wrote:

Same behavior with add_contact_alias()

 

-dan

 

 

From: "miconda@gmail.com" <miconda@gmail.com>
Reply-To: "miconda@gmail.com" <miconda@gmail.com>
Date: Thursday, April 2, 2020 at 2:59 PM
To: "Kamailio (SER) - Users Mailing List" <sr-users@lists.kamailio.org>, Daniel Graham <dan@cmsinter.net>
Subject: Re: [SR-Users] nathelper without usrloc

 

Hello,

can you try with add_contact_alias() instead of set_contact_alias()? The second one updates the contact URI in a way that is visible for the couple of local modules immediately, typically needed when having dialog/presence module in that instance (still no changes to the header itself, it uses some internal mechanism to signal contact value should be taken from a special field). The first one uses the lumps system that makes the changes over the contact URI not visible immediately (unless msg_apply_changes() is used).

Maybe nat_keepalive() needs the original contact URI, not the one updated by set_contact_alias().

Cheers,
Daniel

On 02.04.20 18:45, Daniel W. Graham wrote:

I was able to fix all issues, but have one partially lingering.

 

For register only, if I apply: set_contact_alias() with nat_keepalive(), keepalives are not sent. Removing set_contact_alias() fixes this.

 

I *shouldn’t need this if the pbx was saving received and rport params as a result of add_path_received().

 

Can anyone explain why these two functions conflict?

 

Test scenario -

# Doesn’t result in register keepalive –

 

route[NATDETECT] {

    force_rport();
    set_contact_alias();  # removal of this enables keepalive
    nat_keepalive();
    return;
}

 

I’ve tested this with and without calls to handle_ruri_alias() elsewhere in cfg script with same result.

 

-dan

 

From: sr-users <sr-users-bounces@lists.kamailio.org> on behalf of Sergiu Pojoga <pojogas@gmail.com>
Reply-To: "Kamailio (SER) - Users Mailing List" <sr-users@lists.kamailio.org>
Date: Wednesday, April 1, 2020 at 8:58 AM
To: "Kamailio (SER) - Users Mailing List" <sr-users@lists.kamailio.org>
Subject: Re: [SR-Users] nathelper without usrloc

 

Nothing else comes to mind based on info provided. May be you can send some sip traffic captures and elaborate?

 

Regards,

--Sergiu 

 

On Tue, Mar 31, 2020 at 10:29 PM Daniel W. Graham <dan@cmsinter.net> wrote:

Thanks, yeah I had already changed that, but registration works with either. I’m not asking for a solution, just looking for suggestions on anything that needs attention, so I appreciate your pointers. 

 

-dan

On Mar 31, 2020, at 8:55 PM, Sergiu Pojoga <pojogas@gmail.com> wrote:

 

Oh and almost forgot - try add_path_received() instead of add_path()

 

Good luck!

 

On Tue, Mar 31, 2020 at 8:48 PM Sergiu Pojoga <pojogas@gmail.com> wrote:

A lot of things may not be 'right' here, unfortunately your question is too broad to answer and too little info, the topology is indeed non-default and I doubt someone will present you with a final solution (there's business support, if you're looking for that).

 

Otherwise, if I were to just throw a guess: 

- try fix_nated_register() (instead of set_contact_alias) just for Register method on the way to the registrar

- in the Registrar, make sure the Contact's Path address is correct

 

Cheers,

--Sergiu

 

On Tue, Mar 31, 2020 at 7:34 PM Daniel W. Graham <dan@cmsinter.net> wrote:

It did help, I read that a couple times already but something is still not right, and its only because of the decoupling of the registrar. I need to do more debugging and see if Im loosing the flag value. Hoping something sticks out that someone sees and can point me in the right direction.

-dan

On Mar 31, 2020, at 7:15 PM, Alex Balashov <abalashov@evaristesys.com> wrote:
>
> Daniel,
>
> Might this article be of aid?
>
> http://www.evaristesys.com/blog/server-side-nat-traversal-with-kamailio-the-definitive-guide/
>
> -- Alex
>
>> On Tue, Mar 31, 2020 at 11:12:23PM +0000, Daniel W. Graham wrote:
>>
>> It does but doesn't work as well as kamailio, and since the proxy is the entry point.
>>
>> The biggest issue here isnt the keepalive, as I did have that working. The main issue is the routing of messages, utilizing set_contact_alias and handle_ruri_alias, as Ive been unable to get ack and bye messages to make it past the proxy. I’m assuming these functions are not being used at the right locations or I need to rely on another mechanism to accomplish it. I also question my use of the PBX flag and the natmanage logic.
>>
>> -dan
>>
>> On Mar 31, 2020, at 7:01 PM, Sergiu Pojoga <pojogas@gmail.com> wrote:
>>
>>
>> Hi Daniel,
>>
>> From what you are describing, my understanding is that the Registrar is the PBX, kamailio is acting as an edge proxy. If so, doesn't the PBX/registrar have NAT traversal/keepalive mechanisms of its own?
>>
>> Regards,
>> --Sergiu
>>
>> On Tue, Mar 31, 2020 at 1:55 PM Daniel W. Graham <dan@cmsinter.net<mailto:dan@cmsinter.net>> wrote:
>> I’ve been missing with this for a while and seem to be missing something. Any suggestions on what is missing here?
>>
>> Trying to use set_contact_alias() and handle_ruri_alias() from nathelper module and nat_keepalive from nat_traversal module, without registrar.
>>
>> I had register keepalive working, that has since broke. When register keepalive was working, I was able to place call in either direction but ACK and BYE was not being routed past kamailio.
>>
>> Registrations are forwarded to the PBX using add_path() and is working.
>>
>> Also not included below is the routing to the PBX, that is just setting $du and t_relay, and is also working.
>>
>> Topology is: UA1 -> NAT -> kamailio -> PBX -> UA2
>>
>> Using default config file as the example, modified with above changes. I also removed RTP config as that is a non-issue.
>>
>> request_route {
>>    ……
>>    # FLAG MESSAGES FROM PBX
>>        setflag(FLT_PBX);
>>    route(NATDETECT);
>>    ……
>>
>> route[NATDETECT] {
>>            if (nat_uac_test("19")) {
>> force_rport();
>>                        set_contact_alias();
>>                        nat_keepalive();
>>            }
>>            return;
>> }
>>
>> route[WITHINDLG] {
>>            if (!has_totag()) return;
>>                        if (loose_route()) {
>>                                    route(DLGURI);
>>                        } else if ( is_method("ACK") ) {
>>                                    route(NATMANAGE);
>>                        } else if ( is_method("NOTIFY") ) {
>>                                    record_route();
>>                        }
>>            route(RELAY);
>>            exit;
>>            }
>>
>>            if (is_method("SUBSCRIBE") && uri == myself) {
>>                        route(PRESENCE);
>>                        exit;
>>            }
>>            if ( is_method("ACK") ) {
>>                        if ( t_check_trans() ) {
>>                                    route(RELAY);
>>                                    exit;
>>                        } else {
>>                                    exit;
>>                        }
>>            }
>>            sl_send_reply("404","Not here");
>>            exit;
>> }
>>
>> route[NATMANAGE] {
>>        if(isflagset(FLT_PBX)) {
>>            handle_ruri_alias();
>>    }
>>    if(!isflagset(FLT_PBX)) {
>>        set_contact_alias();
>>    }       return;
>> }
>>
>> route[DLGURI] {
>>            if(!isdsturiset()) {
>>                        handle_ruri_alias();
>>            }
>>            return;
>> }
>>
>> branch_route[MANAGE_BRANCH] {
>>            route(NATMANAGE);
>> }
>>
>> onreply_route[MANAGE_REPLY] {
>>            if(status=~"[12][0-9][0-9]") {
>>                        route(NATMANAGE);
>>            }
>> }
>> failure_route[MANAGE_FAILURE] {
>>            route(NATMANAGE);
>>
>>            if (t_is_canceled()) exit;
>>
>>
>> -dan
>>
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users@lists.kamailio.org<mailto:sr-users@lists.kamailio.org>
>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users@lists.kamailio.org
>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users@lists.kamailio.org
>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>
>
> --
> Alex Balashov | Principal | Evariste Systems LLC
>
> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
>
> _______________________________________________
> Kamailio (SER) - Users Mailing List
> sr-users@lists.kamailio.org
> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
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_______________________________________________
Kamailio (SER) - Users Mailing List
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-- 
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
-- 
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
-- 
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
-- 
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
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