Andrei Pelinescu-Onciul schrieb:
On Jan 21, 2010 at 17:37, Klaus Darilion klaus.mailinglists@pernau.at wrote:
Hi!
The sr/ser/kamailio smaple configs contain:
if (!t_relay()) { sl_reply_error(); }I wonder if this is still the case. I did some TCP tests and when the TCP forwarding fails (e.g. RST received or set_forward_no_connect() activated), then tm module itself replies stateful with 477 and then returning to script with FALSE. Thus, sl_reply_error will send 500 response stateless too.
t_relay() will return error if it fails to create a transaction (unlikely, only on out-of-mem), send failed on all branches (your case), cancel failed or stateless ACK forwarding failed. tm will send an error reply only if no other statefull reply (t_reply()) is sent in the script.
One way to handle this from the script is first to try t_reply() and only if t_reply() fails, sl_reply_error(). E.g.: if (!t_relay()){ if (!t_reply("500", "Some error")) sl_reply_error(); }
Is it also possible to t_relay the call a second time? For example relaying failed as the destination SIP proxy is not available can I redirect the call to an announcement server? e.g.:
if (!t_relay()){ if (t_lookup_request()) $du = "sip:announcement01@1.2.3.4"; t_relay(); exit; else sl_reply_error(); }
regards Klaus
Another possible way: if (!t_relay()){ if (t_lookup_request()) exit; # transaction exists -> exit to trigger the auto-reply else sl_reply_error(); }
You could also use t_newtran(). If t_newtran() fails => sl_reply(). If it doesn't and t_relay() fails => t_reply() let tm generate the reply.
IMO if tm module already sent a final response, it should exit without entering script again.
tm sends a final response only at the end of the script and only no other reply was sent from the script via t_reply. This allows overriding the final reply from the script.
Even better would be to reply only if there is no failure route sent.
Further, if TCP forwarding fails due to set_forward_no_connect() it logs:
ERROR: tm [../../forward.h:169]: msg_send: ERROR: tcp_send failed ERROR: tm [t_fwd.c:1235]: ERROR: t_send_branch: sending request on branch 0 failed
IMO it would be good to log this only with L_INFO, as it is not an error, but intended behavior.
Agreed, but is quite hard to propagate the reason for the send failure back to tm.
Andrei