[SR-Users] missing BYE when 2 redundant kamailio servers share the same database

[Ding Ma]

Hi, all



I'm trying to set up 2 kamailio servers for active-active redundancy. The
two kamailio severs share the the same database with db_mode=3, and no
registration replication. Use pjsua2 as SIP client for testing. The test
setup is as follows:



kamailio server 1(k1): 10.0.1.30:5061

kamailio server 2(k2): 10.0.1.32:5061

sip client c1: sip:16317 at 10.0.1.30, client ip: 10.0.1.254

sip client c2: sip:72316 at 10.0.1.30, client ip: 10.0.1.254



c1 is registered with k1.

c2 is registered with k2.



When c1 calls c2, the call flow is as follows:

INVITE:

c1------>k1------>k2------>c2

200 OK:

c1<------k1<------k2<------c2



So far, the INVITE works. c1 and c2 can establish a call. However, when c2
hangs up and sends BYE, the BYE is forwarded all the way to k1, and then k1
gives a 500 server error.

The log on k1 seems to indicate k1 was attempting to create a TLS
connection to itself instead of using the existing TLS connection to c1 to
forward the BYE.



BYE:

c1   X   k1<------k2<------c2

       |

       |------->Connection refused/500



Here is the kamailio log on k1:

Mar 16 10:34:21 kamailio.sip.com /usr/sbin/kamailio[13396]: ERROR: <core>
[tcp_main.c:2740]: tcpconn_1st_send(): connect 10.0.1.30:55999 failed (RST)
Connection refused

Mar 16 10:34:21 kamailio.sip.com /usr/sbin/kamailio[13396]: ERROR: <core>
[tcp_main.c:2750]: tcpconn_1st_send(): 10.0.1.30:55999: connect & send  for
0x7fc96a68a1a0 failed: Connection refused (111)



This is the routing logic for BYE in kamailio.cfg:

                if (loose_route()) {

                        route(DLGURI);

                        if (is_method("BYE")) {

                                xlog("L_DBG", "=====BYE $ru from $fu
$si:$sp to $du=====\n");

                                dlg_manage();

                                setflag(FLT_ACC); # do accounting ...

                                setflag(FLT_ACCFAILED); # ... even if the
transaction fails

                        }

                        else if ( is_method("ACK") ) {

                                # ACK is forwarded statelessy

                                route(NATMANAGE);

                        }

                        else if ( is_method("NOTIFY") ) {

                                # Add Record-Route for in-dialog NOTIFY as
per RFC 6665.

                                record_route();

                        }

                        route(RELAY);

                        exit;

                } else {......



If I add location based routing for BYE from peer kamailio, then the BYE
seems to be forwarded correctly:

                if (loose_route()) {

                        route(DLGURI);

                        if (is_method("BYE")) {

                                xlog("L_DBG", "=====BYE $ru from $fu
$si:$sp to $du=====\n");

                                dlg_manage();

                                setflag(FLT_ACC); # do accounting ...

                                setflag(FLT_ACCFAILED); # ... even if the
transaction fails

                                # If BYE coming from Kamailio  peer, route
BYE by location

                                $var(peerlist)=$sel(cfg_get.trusted.peers);

                                $var(i) = 0;


while($var(i)<$(var(peerlist){param.count})) {

                                        xlog("L_DBG",
"=====$(var(peerlist){param.count})=====$(var(peerlist){param.valueat,$var(i)})=====\n");


if(src_ip==$(var(peerlist){param.valueat,$var(i)})) {

                                                lookup("location");

                                                xlog("L_DBG", "=====BYE
from $fu $si:$sp to $du=====\n");

                                                break;

                                        }

                                        $var(i) = $var(i) + 1;

                                }

                        }

                        else if ( is_method("ACK") ) {

                                # ACK is forwarded statelessy

                                route(NATMANAGE);

                        }

                        else if ( is_method("NOTIFY") ) {

                                # Add Record-Route for in-dialog NOTIFY as
per RFC 6665.

                                record_route();

                        }

                        route(RELAY);

                        exit;

                } else {......



My first question is why k1 loose_route sends the BYE to itself instead of
the client. Is this a bug?

My next question is whether the above location routing for BYE from peer
kamailio a good/safe approach.

The SIP traces are enclosed.



Thanks
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