Thanks for the feedback. Corey, thanks for the work on the library.
Meanwhile I implemented the workaround: let Kamailio forward the request
to an Asterisk server which does the lookup and responds with a 302
redirect to (Transfer()) the proper Asterisk server.
Using SIP for the query has the advantage that the query is handled
asynchronous inside Kamailio. For INVITEs it is quite easy (as they are
handled in the Asterisk dialplan of the Asterisk server which does the
DUNDI query). But it was a bit more complicated than expected as I also
have to do the lookups also for REGISTERs, SUBSCRIBE .... Therefore I
implemented a "hack" in Kamailio, faking another INVITE transaction
while putting the original transcation on hold. (yes there are plenty of
hacks you can do in Kamailio).
Basically it works but I have not tested it in detail. If you are
interested take a look at the Kamailio config below.
regards
Klaus
dundi.host = "1.2.3.4:5060" desc "Asterisk which performs the DUNDI
query. Host:Port"
dundi.deftarget = "2.3.4.5:5160" desc "Default Asterisk server if DUNDI
lookup failed. Host:Port"
route[RELAY_TO_DUNDI] {
$var(dundicache) = $sht(dundicache=>$tU);
if( $var(dundicache) == 0) {
xlogl("L_INFO","$tU not found in cache, quering
Dundi-Asterisk for DUNDI lookup...");
if(t_suspend()) {
# build a new transaction, use From and To URI
to store
# the transaction identifiers
xlogl("L_INFO","transaction suspended
[$T(id_index):$T(id_label)]\n");
$uac_req(method)="INVITE";
$uac_req(ruri)="sip:" + $tU + "@" +
$sel(cfg_get.dundi.host);
$uac_req(furi)="sip:" + $T(id_index) + "@proxy";
$uac_req(turi)="sip:" + $T(id_label) + "@proxy";
$uac_req(callid)=$(mb{s.md5});
uac_req_send();
exit;
} else {
xlogl("L_ERR","Failed to suspend transaction
... 500");
send_reply("500","Failed to suspend transaction");
exit;
}
} else if( $var(dundicache) == "unknown" ) {
xlogl("L_INFO","$tU found in cache but unknown, sending
to $(sel(cfg_get.dundi.deftarget))");
$du="sip:" + $sel(cfg_get.dundi.deftarget);
} else {
xlogl("L_INFO","$tU found in cache, sending to
$var(dundicache)");
$du="sip:" + $var(dundicache);
}
add_contact_alias();
if (!t_relay()) {
sl_reply_error();
}
exit;
}
event_route [tm:local-request] {
# Handle locally generated requests
xlogl("L_INFO", "local-request: Routing locally generated $rm
to <$ru>:");
t_on_reply("REPLY_DUNDI");
# 2 seconds prober timeout
t_set_fr(0, 2000);
}
onreply_route[REPLY_DUNDI] {
xlogl("L_INFO","REPLY_DUNDI: response received from $si:");
$var(index) = $(fU{s.int});
$var(label) = $(tU{s.int});
if (t_check_status("3[0-9][0-9]")) {
# this reply route is only executed for DUNDI
responses, thus, no need to check the source
$var(target)= @msg.header.Contact[0].nameaddr.uri.host;
xlogl("L_INFO","REPLY_DUNDI: Tindex=$var(index),
Tlabel=$var(label), target=$var(target)");
$sht(dundicache=>$fU:$tU)=$var(target);
t_continue("$var(index)", "$var(label)", "AFTER_DUNDI");
} else {
xlogl("L_ERR", "Unexpected response from Dundi server");
t_continue("$var(index)", "$var(label)", "AFTER_DUNDI");
}
}
route[AFTER_DUNDI] {
xlogl("L_INFO","AFTER_DUNDI: transaction
$T(id_index):$T(id_label) continues ....");
$var(target) = $sht(dundicache=>$T(id_index):$T(id_label));
if ($(var(target){s.len}) > 1) {
$du = "sip:" + $var(target);
$ru = $ou;
xlogl("L_INFO", "Got redirect from Dundi server, target
is $ru, sending to $du");
$sht(dundicache=>$tU)=$var(target);
r_relay();
exit;
} else {
xlogl("L_ERROR","AFTER_DUNDI: no target found ... using
default");
$du="sip:" + $sel(cfg_get.dundi.deftarget);
$ru = $ou;
$sht(dundicache=>$tU)="unknown";
r_relay();
exit;
}
exit;
}
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