Re: [Kamailio-Users] correct usage of t_reply - sr-users

11 Apr 2009

On Sat, Apr 11, 2009 at 1:19 PM, David Aldworth &lt;daldworth(a)teliax.com&gt; wrote:
...
  Is there a way to tell if a transaction already exists
before executing
 t_newtran(); ? 
I suppose you could use  t_check_trans().
But I haven't tried it.

...
  If the route query scripts executes resulted in a
route, but then we get a
 5XX from upstream, a transactions then exists. When it tries to execute
 t_newtran(); I get the following:

 ERROR:tm:t_newtran: transaction already in process 0x2873dd08

 If the query did not get a route, and no transaction exists, then executing
 t_newtran(); before the t_reply works perfectly.

 Using sl_send_reply works, but if the transaction does exist then it sends
 *two* 5XX messages back to the UAC. This is actually not harmful as far as I
 can tell. But it's not clean either. 
I think at any point in the cfg it should be clear to the
reader/writer where a transaction exists or not depending of which
functions were called. I mean, you should know it. If you must
recourse to some function to tell if a transaction exists or not, then
I think the cfg is not clear.

regards,
takeshi

P.S.: please, always CC to the list.

...
  On Apr 10, 2009, at 10:06 PM, mayamatakeshi wrote:

  On Sat, Apr 11, 2009 at 12:53 PM, David Aldworth
&lt;daldworth(a)teliax.com&gt;
 wrote:

 I'm am attempting to return a 503 "Service Unavailable" after my
 kamailio server sends the provisional response to customer UA if we
 cannot find a route for the call. I am using:

 t_reply("503", "Service Unavailable");

 However this results in:

 ERROR:tm:w_t_reply: failed to send a t_reply to a message for which no
 transaction-state has been established

 Reading up on t_reply, it clearly states: "Sends a stateful reply
 after a transaction has been established." So, I guess thats means
 even though we have received the invite, and send 100 Trying back, a
 transaction does not actually exist.

 So, my question is, how do I tell the sending UAC that we are 5XX so
 that it can stop sitting there waiting for session progress? 
 Hello,
 you can send the reply statelessly:
 sl_send_reply("503", "Service Unavailable" );

 or statefully:
 t_newtran();
 t_reply("503", "Service Unavailable");

 Before you can use t_reply, a transaction must be established. This
 can be done explicitly calling t_newtran() or it will be do internally
 by other functions like t_relay.

 regards,
 takeshi. 