Re: [Users] ACK Routing: Best practices?

Hi Carsten! First I would differ between ACK and CANCEL. If you use statefull forwarding, then it is sufficient to just t_relay, as tm will take care of hop-by-hop canceling. There is no need to rewrite the R-URI. There is only one problem: If the INVITE processing takes more time, than it may happen that the CANCEL hits the tm module before the tm module created a transaction. Thus, I discard CANCEL without existing transactions. ACK: There are 3 kinds of possible ACK. 1. stateless, e.g. if you use sl_send_reply("404",""), then the client will send a "stateless" ACK. This ACK will be absorbed by openser as soon as it is received and will never enter the routing logic. Thus, we do not have to care about them. 2. statefull, sucessful call: The INVITE was answered with 200, thus the caller sends an ACK to the callee. This ACK is in-dialog, and thus should be routed by the loose_route block (no need to rewrite any URI) 3. statefull, unsuccessful call: The call was rejected or cancelled. Thus, we have hop-by-hop ACKs. Thus, the ACK must be handled to the tm moudle, which takes care of it (no need to rewrite any URI). here is how I handle ACK and CANCEL. I did not had any issues with this (running now since 1 year). if ( is_method("CANCEL") && !t_check_trans() ) { # CANCEL without matching INVITE transaction, ignore # may happen if the INVITE is slower than the CANCEL # ignore the CANCEL, as the client will retransmit it, and maybe next time # the INVITE transaction is already created xlog("L_WARN","$ci CANCEL without matching transaction ... ignore and discard.\n"); exit; } route(8); # disable mediaproxy (needs to see valid CANCEL requests) force_send_socket(83.136.32.160:5060); # force port 5060 as sending port if ( is_method("CANCEL") ) { # CANCEL with matching INVITE transaction, just # t_relay xlog("L_INFO","$ci CANCEL with matching transaction ... t_relay.\n"); t_relay(); exit; } # check every message for Remote-Party-Id: header and remove it if (is_present_hf("Remote-Party-ID")) { xlog("L_INFO", "$ci Remote-Party-ID header present ...removing\n"); remove_hf("Remote-Party-ID"); } if (loose_route()) { # loose route requests are not authenticated xlog("L_INFO","$ci beginning loose_route processing...\n"); route(32); # handle in-dialog requests exit; } if ( is_method("ACK") ) { if ( t_check_trans() ) { # non loose-route, but stateful ACK; must be an ACK after a 487 xlog("L_INFO","$ci local end-to-end ACK for an existent INVITE transaction detected ...t_relay()\n"); t_relay(); } else { xlog("L_WARN","$ci ACK without matching transaction ... ignore and discard.\n"); } exit; } if ( has_totag() ) { # in-dialog requests should be handled by loose_route # this should be fixed in the client or in openser xlog("L_ERR","$ci in-dialog request was not catched by loose_route block, 403... \n"); xlog("L_ERR","$ci this is the complete message:\n"); xlog("L_ERR","$ci $mb\n"); sl_send_reply("403","in-dialog request without loose_route is not allowed, this is a bug in the client or in this proxy\n"); exit; } route(7); # proxy authentication regards Klaus Carsten Bock wrote: ################################################################################################################## ############################################################################################################### ################################################################################################################## ############################################################################################################### ################################################################################################################## ############################################################################################################### ################################################################################################################## ############################################################################################################### example: _______________________________________________ Users mailing list Users(a)openser.org http://openser.org/cgi-bin/mailman/listinfo/users