23 aug 2013 kl. 12:13 skrev Steve Davies <steve@connection-telecom.com>:




On 23 August 2013 11:18, Steve Davies <steve@connection-telecom.com> wrote:
Here's what I put in RELAY route block:

        $var(rr) = t_relay();
        xlog("L_NOTICE","SLD: in RELAY, t_relay returned $var(rr)\n");
        if (!$var(rr)) {
                sl_reply_error();
        }


In 4.0.3, t_relay gives a -1 in the case that there is a physical network issue (in my test I have a "-j DROP" iptables rule)


Trying to find a way to detect the case where t_relay fails but doesn't call the failure block.  I dumped some hopeful looking pseudo variables, and tried to use an avp to communicate from the failure branch back to the relay point.

I tried this:

        $avp(senttoast) = 0;
        $var(rr) = t_relay();
        xlog("L_NOTICE","SLD: in RELAY, t_relay returned $var(rr) err.rcode is $err.rcode t_r_c is $T_reply_code sent = $avp(senttoast)\n");
        if ($var(rr) < 0) {
                sl_reply_error();
        }

and in my failure block I set $avp(senttoast) to 1.


I get:

Aug 23 12:07:02 ubuntu /usr/local/sbin/kamailio[7819]: NOTICE: <script>: SLD: in RELAY, t_relay returned -1 err.rcode is <null> t_r_c is 100 sent = 0

In the case of a 477 being sent back.  So I can't find anything distinctive so far.

In the case of a soft failure (I have the upstream send a 500):

Aug 23 12:09:32 ubuntu /usr/local/sbin/kamailio[7817]: NOTICE: <script>: SLD: in RELAY, t_relay returned 1 err.rcode is <null> t_r_c is 100 sent = 0

So the same.

From the trace I can see that the failure block is only executed after the t_relay returns.  The failure block runs on a different pid.

So there is a race.  Or maybe the avp doesn't work across branches or something?

Clues would be welcome!

THe failure route is executed when a transaction fails, i.e. ends with a code higher than 299.

The failure of t_relay happens when you try to send to something that doesn't exist or something similar.

set 

$du="sip:127.0.0.2:1234;transport=udp";

and run t_relay to get an error. Or 

$du="sip:steve.davies.learns.kamailio@jburg.example.com;transport=udp";

(for DNS errors)

or

$du = "sip:david.duffet@www.digium.com:80;transport=tcp";

(for connection errors).

Test with those to see different behaviours.

/O