Hi Henning

not sure about your motivation in using this method on a busy production system. Usually this is not necessary.

The motivation is to provide a diagnosis tool to our customer helpdesk.

(And also for me as a tech, to for example find long running calls and other stuff I might be interested in).

Simplified:

Customer Service enters a phone number of a customer and get an output of all settings like call forwarding (obtained from DB by our own API). But also information about registered AOR and their contacts (obtained by ul.dump) and as bonus: Information about active calls of the customer to which this phone number belongs.

So I was looking for a way to gather the dialogues involving the phone number or better, AOR in question.

dlg.dlg_list needs the call-id, which is not known.

dlg.list_match is limited regarding what key can be used. It probably would work with trying to somehow partially matching ruri or furi, but we translate numbers, so that is a bit fuzzy and might return wrong matches or not match if clip-no-screening is used.

The most promising would be to use dlg.list and then loop through the variables to find the dialogues associated with the authentication username (equal to the AOR in our case) of the customer to which the dialogue belongs to.

As I kept running into DMQ sync issues with storing dialogue information in database, I switched off database support for dialogue.

Hi Benoît,

Having gone down this road myself, I would corroborate what Henning has to say.

Getting large amounts of dialog info in bulk from the JSONRPCS API isn't a particularly good avenue, even if you can make it work with the various buffer sizes. I would also be concerned about any big locks required when iterating over the dialog structures as a whole, since they are stored in shared memory. In many cases, just because something is technically possible doesn't mean you should do it. It seems to me that `dlg.list` may be one of those RPC commands that's best suited to troubleshooting or debugging, rather than regular operational usage. (To be fair, I don't know the locking approach when reading the entire structure, and I imagine some work has gone into optimising it.)

What DMQ sync issues with DB storage have you found? I haven't tried it myself, but I would imagine a promising approach would be to have a DMQ peer node whose sole purpose is to sync dialogs to a DB. Have you tried that? Has it not worked out?

-- Alex

On Jan 20, 2023, at 9:08 AM, Benoît Panizzon benoit.panizzon@imp.ch wrote:

Therefore the dialog module is used to gather cdrs, but to ensure translated numbers are translated the other way on replies and many more.

I'm not familiar with this latter usage of the dialog module. Could you explain that further?

I noticed, when I restart kamailio after doing config changes, that entries kept accumulating with each restart in the 'dialog' and 'dialog_vars' tables, never expiring even the next day, when the dialog timeout we set to 12 hours should have made sure they got expired.

And you're sure you've got these modparams configured correctly for this expectation?

https://kamailio.org/docs/modules/5.6.x/modules/dialog.html#dialog.p.update_...

https://kamailio.org/docs/modules/5.6.x/modules/dialog.html#dialog.p.db_mode

-- Alex

I think you might be working too hard. :-)

1. Automatic stateful reversion of From and To header modifications is available in the `uac` module:

https://kamailio.org/docs/modules/5.6.x/modules/uac.html#uac.p.rr_from_store...

https://kamailio.org/docs/modules/5.6.x/modules/uac.html#uac.p.restore_mode

https://kamailio.org/docs/modules/5.6.x/modules/uac.html#uac.p.restore_dlg

If you are already using these, then disregard. But if you're not, they will take care of the reversion for you so you don't have to manually mangle any replies or in-dialog requests.

2. R-URI is not present in replies, so this should not be relevant;

3. Most other one-way message changes specific to a given carrier or other gateway destination can be done in branch_route, in which case the reversion to the original value is automatic when attempting another destination.

For example:

request_route { ...

# $rU = '999';

if(method === "INVITE") { $du = "sip:1.1.1.1:5060";

t_on_branch("MODIFY"); t_on_failure("NEXT_ONE"); t_relay(); exit; } }

branch_route[MODIFY] { if($nh(d) eq "1.1.1.1") $rU = '+999'; }

This '+999' value will be reverted when NEXT_ONE creates another branch.

-- Alex

On Jan 20, 2023, at 10:06 AM, Benoît Panizzon benoit.panizzon@imp.ch wrote:

Hi Alex

...

I'm not familiar with this latter usage of the dialog module. Could you explain that further?

That is not a module. We use the dlg_vars to store a lot of information. I would love if there was a module taking care of symmetric number translations in all messages. I think this is a common task.

Consider this situation (intentionally using invalid prefixes)

Interconnection uses e164 Numbers. eg: +41661234567 for Switzerland and we use NPRN (number portability routing prefixes) numbers to route ported numbers. Customer uses 'national' notation of same number: 0661234567

Call from Customer:

RURI: 0661234567 (this is ported to NPRN 99052) From: 0667776655

Call towards IC therefore has to be:

RURI: +4199052661234567 From: +4166776655

So I store the original FROM and RURI in dlg_variables so I can put them back in the appropriate header when passing a RINGING or 200 OK back to the customer.

Even more important. When there is a Privacy: ID Header present: I (by OFCOM regulations MUST) replace $fu and $fn with 'Anonymous' towards the customer. And of course also the Contact: Username and possibly remove PAI, PPI or whatever the customer does not need to get. But I might want to send him the Diversion Header to indicate who diverted the call, it it's privacy flag allows it of course.

On any subsequent messages, re-invites, whatever else is getting sent to the customer. I have to make sure I don't disclose the calling number by mistake (customer could be logging those on his CPE). So, yes, plenty of header usernames to track and replace for all kind of messages and transactions within a dialogue.

...

...

I noticed, when I restart kamailio after doing config changes, that entries kept accumulating with each restart in the 'dialog' and 'dialog_vars' tables, never expiring even the next day, when the dialog timeout we set to 12 hours should have made sure they got expired.

And you're sure you've got these modparams configured correctly for this expectation?

https://kamailio.org/docs/modules/5.6.x/modules/dialog.html#dialog.p.update_...

https://kamailio.org/docs/modules/5.6.x/modules/dialog.html#dialog.p.db_mode

I will give it another try :-)

-- Mit freundlichen Grüssen

-Benoît Panizzon- @ HomeOffice und normal erreichbar

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