On 19.09.2012 16:13, Yufei Tao wrote:
I should have made it clearer: $du is null both before and after lookup
location in LOCATION_BRANCH when no fix_nated_register was done (thus
'received' column in location table was null). When fix_nated_register
was done, $du for each branch was null before lookup location, but set
to 'received' after lookup location as you said. But in this case
(fix_nated_register done), everything works fine.

So seems now the problem happens when: 'received' in location table is
null, causing $du not to be set. I used to think $du is only set by
record-route and thanks for clarifying this :)

Even when without fix_nated_register (thus no 'received'), the lookup
location for each branch, i.e. y2 and y3, set $ru to the 'contact' field
successfully, but $du isn't set. But Kamailio did relay to the first
branch (trunk?) and not the others. So the first branch is handled
differently? So maybe when $du is null, should set it to $ru on the
branches?

There is no need to set $du. If $du is null, $ru is used for routing.

Can you verify with ngrep/tcpdump (capture on 'any' interface) if there is no SIP message sent to y2/y3 or the message is sent, but to wrong destination (e.g. same target as first branch).

regards
Klaus


Yufei


On 19/09/12 11:53, Klaus Darilion wrote:


On 19.09.2012 12:24, Yufei Tao wrote:
Hi Klaus

Thanks for the reply!

I check the $du, it is always null before and after the lookup. Is it
only set when relaying to a proxy (from record-route), and not to a
client?

That's strange. For NATed clients, $du must contain the 'received'
URI. Otherwise they can not be contacted as $ru contains the private
IP address.

When no fix_nated_register is called, the lookup location for both
clients y2 and y3 is successful from the log, when printing out $ru
after lookup. But seems Kamailio only relays to one client's IP while
not others. I think there must be some differences when branch route is
executed first time and second time as you said. As it feels like for
the first branch (trunk?) it used the 'contact' column from the location
table, and for the other branches, it tries to use 'received'?

It seems db_lookup() creates multiple branches. Is lookup() only
finding 1 contact in table or multiple contacts?

regards
Klaus



Yufei

On 18/09/12 18:49, Klaus Darilion wrote:
I suspect that the branch route is first executed for the NATed
client. Then the 'received' column is used as destination URI. When
executing the branch route again, the destination URI is still the
value from the previous branch, and lookup() will not overwrite is as
'received' is not available. Then Kamailio sends the INVITE again to
the first client.

You can try to set $du to Null before lookup(). ($du=null or
$du=$null, not sure what the correct syntax is).

Another workaround is to use fix_nated_register() for every client
(the pragmatic and more secure approach).

regards
Klaus

On 18.09.2012 15:16, Yufei Tao wrote:
Hi

I have a strange problem on forking calls to a group of users. For
example I have two users y2 and y3 in dbaliases, both with
alias_username 'group'. And y2 and y3 both registers with Kamailio
fine.
When I make a call to 'group' from a third client y1, what my
kamailio.cfg does is: do an alias_db_lookup("dbaliases"), and goes to
BRANCH_ALIASDB, where a lookup location will be done for each of the
username resulting from lookup of dbaliases, something like this:

y1--INVITE 'group'-->lookup
dbaliase-->[BRANCH_ALIASDB]--->'y2'-->lookup
location---¬

|                                                 |-->relay

---->[BRANCH_ALIASDB]--->'y3'-->lookup
location----

The all works well as long as all clients are NAT'ed. However when
they
are not NAT'ed, e.g. all on the same LAN with Kamailio, the call only
goes to one of the group members, e.g. y2 only. When checking the log,
it seemed to have done the dbaliases lookup fine, and each location
lookup successfully. But Kamailio only relayed y2's IP, e.g. to the
client, while y3's to itself.

When comparing the location table when clients are NAT'ed or not, I
find
that the 'received' column is only populated when I do
fix_nated_register. And group calls only works when 'received'
column is
populated. That explains why when clients are NAT'ed group calls work,
as I only do fix_nated_register if nat_uac_test returns true.

But if this is the only reason, if two clients register using the same
username, e.g. both as y3, and when 'received' column of location
table
is empty (no fix_nated_register done), I would expect a call to y3
should also only make 1 client ring. But in fact both of them rang!
The
flow is like:

y1--INVITE 'y3'-->lookup location for 'y3'----> IP of 1st client
registered as 'y3'
                                              |
                                              ---> IP of 2nd client
registered as 'y3'

While a call to 'group' (thus dbaliases lookup took place) under such
un-NAT'ed set up made only 1 client ring.

So I can make it work by always doing fix_nated_register. But I'm not
clear about these things:
- why does a lookup of dbaliases before lookup of location make such
difference?
- does lookup location work differently depending on whether it is
called from trunk or from a route called from a branch route?


Following is relevant parts from my config file:

#############################################################
route[LOCATION]
{
      if ( alias_db_lookup("dbaliases") )
      {
        t_on_branch("BRANCH_ALIASDB"); # in
branch_route[BRANCH_ALIASDB],
                                       # call another route that
looks up
location,
                                       # if not existent, call drop()

      }
      else
      {
        xlog("L_DBG","LOCATION: not alias - go to lookup location
trunk\n");
        route(LOCATION_TRUNK); # normal look up location and sending of
404 etc
      }

... ...
}
#############################################################
branch_route[BRANCH_ALIASDB]
{
      xlog("L_DBG", "BRANCH_ALIASDB: $fU@$fd ->  $rU@$rd;
Method:$rm\n");
      route(LOCATION_BRANCH);
}

route[LOCATION_BRANCH]
{
      if (!lookup("location"))
      {
        # Drop this branch - it's going nowhere
        drop();
      }
}
#############################################################
route[RELAY] {
      xlog("L_DBG","RELAY: method=$rm, callid=$ci, cseq=$cs\n");


#!ifdef WITH_NAT
      if (check_route_param("nat=yes")) {
        setbflag(FLB_NATB);
      }
      if (isflagset(FLT_NATS) || isbflagset(FLB_NATB)) {
        xlog("L_DBG", "RELAY: about to call RTPPROXY\n");
        route(RTPPROXY);
      }
#!endif

      /* example how to enable some additional event routes */
      if (is_method("INVITE")) {
        t_on_reply("REPLY_ONE");
        t_on_failure("FAIL_ONE");
      }

      if (!t_relay()) {
        sl_reply_error();
      }

      exit;
}

############################################################
route[NAT] {
#!ifdef WITH_NAT
     xlog("L_DBG","NAT: method=$rm, callid=$ci, cseq=$cs\n");

       force_rport();
       if (nat_uac_test("2")) {
           if (method=="REGISTER") {
               fix_nated_register();
               xlog("L_DBG","NAT: Just done fix_nated_register in
REGISTER
message in NAT route\n");
           } else {
             xlog("L_DBG","NAT: fix_nated_contact\n");
               fix_nated_contact();
           }
           setflag(FLT_NATS);
       }

#    setflag(FLT_NATS); ## -- YT: set NAT flag for all, so will force
media relay
#!endif
       return;
}

#############################################################
And in the main route, route LOCATION and RELAY are the last two
routes:
route {
...
      route(NAT);

      ... ...

      # user location service
      route(LOCATION);

      route(RELAY);
}

Hope I have made it clear. Thanks very much!

Yufei
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