[SR-Users] Combining lookup_branches() and t_(next|load)_contacts()

[Nathan Ward]

Hi all,

I’ve worked around this by walking through $branches() and removing entries where dst_uri is $null. This works OK, but feels like a hack:

  # Walk through all the branches, and nuke any which have not resolved - i.e. they do not have a dst_uri set.
  $var(i) = 0;
  while($var(i)<$branch(count))
  {
    xlog('L_DBG', "Looking at branch [$var(i)] with dst_uri [$(branch(dst_uri)[$var(i)])] and ru [$(branch(uri)[$var(i)])]\n");
    if ($(branch(dst_uri)[$var(i)]) == $null) {
      xlog('L_DBG', "Branch [$var(i)] has a null dst_uri, so removing\n");
      $(branch(uri)[$var(i)]) = $null;
    } else {
      $var(i) = $var(i) + 1;
    }
  }

I’d be keen to know if there’s any other ways to achieve this.

I also note that I’m getting a "BUG: freeing already freed pointer” message when the dialog is getting cleaned up. How can I debug this, or, what sort of information is useful to provide for something like this? I’m on 5.1.3.

> On 4/05/2018, at 1:51 PM, Nathan Ward <kamailio-sr-users at daork.net> wrote:
> 
> Hi,
> 
> About a year ago I posted this, but haven’t had much chance to follow up on it:
> https://lists.kamailio.org/pipermail/sr-users/2017-March/096337.html
> 
> I’ve been doing some work on this issue (we worked around it until now), and have reduced the config right down to see where things are going wonky.
> 
> The scenario I have, is inbound calls (to let’s say “A at domain") which I have aliased to two or more different numbers (let’s say “B at domain” and “C at domain”). Both B and C are registering, but are not always registered.
> I resolve the aliases with alias_db_lookup() (in my sample below, I use seturi() and append_branch() to avoid any confusion about where things may be going weird), then look them up in the location table with lookup_branches().
> I then need to do t_load_contacts() and t_next_contacts(), as in some call scenarios I add a serial fork before or after the main call (pre-call announcements etc.).
> Then, I call t_relay().
> 
> This works great most of the time - however, if for example B is registered, but C is not registered, lookup_branches() notes that B is "Not found in usrloc”, and then t_load_contacts() seems to not realise that this isn’t usable, and it attempts to do a DNS lookup for the domain and so on, which I don’t really want it to be doing.
> 
> Should lookup_branches() be removing a branch it can’t resolve? I would expect it to behave like that, anyway. Can I configure it to do that, or do I need to manually loop through them or something to make sure they resolved, and remove the ones that didn’t?
> 
> I’ve tried swapping it around, so I call lookup_branches() after t_next_contacts() but the behaviour is the same.
> 
> I imagine I can’t be the only person trying to do this - how have others made it work?
> 
> 
> Config sample:
> 
> seturi('sip:a at domain');
> append_branch('sip:b at domain');
> xlog("L_DBG", "1 ds: [$ds]\n");
> lookup_branches('location');
> xlog("L_DBG", "2 ds: [$ds]\n");
> t_load_contacts();
> xlog("L_DBG", "3 ds: [$ds]\n");
> t_next_contacts();
> xlog("L_DBG", "4 ds: [$ds]\n");
> 
> --
> Nathan Ward
>