Table of Contents
List of Examples
Table of Contents
This module provides C-API functions to enable Kamailio to be used as an outbound Edge Proxy (see RFC 5626 section 5).
The path and rr will bind to this module if it is loaded before they are.
Outbound Edge Proxies MUST support STUN NAT keep-alives on their SIP UDP ports. Kamailio supports this as a compile-time option that is disabled by default.
The maximum interval at which a User Agent must send a keep-alive may be specified by the Registrar using the Flow-Timer: header in 2xx responses to REGISTERs.
When using TCP or TLS as the SIP transport care should be taken to set the “tcp_connection_lifetime” on the Edge Proxy to a value slightly larger than the interval the Registrar is using for flow timer. Setting “tcp_connection_lifetime” to less than the interval could cause connections to be lost, and setting it to a value much larger than the interval will keep connections open far longer than is required (which is wasteful).
Application-layer keep-alives are optional when the underlying transport already has a keep-alive mechanism. The WebSocket transport has a transport-layer keep-alive. When using the WebSocket transport the “keepalive_timeout” should be set to a value a little greater than the Registrar flow timer interval and a little less than the “tcp_connection_lifetime”.
Example 1.2. Edge Proxy Configuration
#!KAMAILIO
#
# Edge proxy configuration
#
#!subst "/REGISTRAR_IP/192.168.122.3/"
#!subst "/REGISTRAR_PORT/5060/"
#!substdef "/FLOW_TIMER/20/"
####### Global Parameters #########
debug=2
log_stderror=no
log_facility=LOG_LOCAL0
fork=yes
children=4
alias="example.com"
mpath="/usr/lib64/kamailio/modules"
tcp_connection_lifetime=30 # FLOW_TIMER + 10
####### Modules Section ########
loadmodule "tm.so"
loadmodule "sl.so"
loadmodule "outbound.so"
loadmodule "rr.so"
loadmodule "path.so"
loadmodule "pv.so"
loadmodule "maxfwd.so"
loadmodule "xlog.so"
loadmodule "sanity.so"
loadmodule "ctl.so"
loadmodule "mi_rpc.so"
loadmodule "mi_fifo.so"
loadmodule "textops.so"
loadmodule "siputils.so"
# ----------------- setting module-specific parameters ---------------
# ----- mi_fifo params -----
modparam("mi_fifo", "fifo_name", "/tmp/kamailio_fifo")
# ----- tm params -----
modparam("tm", "failure_reply_mode", 3)
# ----- rr params -----
modparam("rr", "append_fromtag", 0)
####### Routing Logic ########
request_route {
route(REQINIT);
if (is_method("CANCEL")) {
if (t_check_trans()) {
route(RELAY);
}
exit;
}
route(WITHINDLG);
t_check_trans();
if (is_method("REGISTER")) {
remove_hf("Route");
add_path();
$du = "sip:REGISTRAR_IP:REGISTRAR_PORT";
} else {
if (is_method("INVITE|SUBSCRIBE"))
record_route();
if ($si == "REGISTRAR_IP" && $sp == "REGISTRAR_PORT") {
if (!loose_route()) {
switch($rc) {
case -2:
sl_send_reply("403", "Forbidden");
exit;
default:
sl_reply_error();
exit;
}
}
t_on_failure("FAIL_OUTBOUND");
} else {
if ($rU == $null) {
sl_send_reply("484", "Address Incomplete");
exit;
}
remove_hf("Route");
$du = "sip:REGISTRAR_IP:REGISTRAR_PORT";
}
}
route(RELAY);
}
route[RELAY] {
if (!t_relay()) {
sl_reply_error();
}
exit;
}
route[REQINIT] {
if (!mf_process_maxfwd_header("10")) {
sl_send_reply("483","Too Many Hops");
exit;
}
if(!sanity_check("1511", "7"))
{
xlog("Malformed SIP message from $si:$sp\n");
exit;
}
}
route[WITHINDLG] {
if (has_totag()) {
if (!loose_route()) {
switch($rc) {
case -2:
sl_send_reply("403", "Forbidden");
exit;
default:
if (is_method("ACK")) {
if ( t_check_trans() ) {
route(RELAY);
exit;
} else {
exit;
}
}
sl_send_reply("404","Not Found");
}
} else {
if (is_method("NOTIFY")) {
record_route();
}
route(RELAY);
}
exit;
}
}
onreply_route {
if (!t_check_trans()) {
drop;
}
if ($rm == "REGISTER" && $rs >= 200 && $rs <= 299) {
remove_hf("Flow-Timer");
if ($(hdr(Require)[*])=~"outbound")
insert_hf("Flow-Timer: FLOW_TIMER\r\n", "Call-ID");
}
}
failure_route[FAIL_OUTBOUND]{
if (t_branch_timeout() || !t_branch_replied()) {
send_reply("430", "Flow Failed");
}
}
Example 1.3. Registrar Configuration
...
loadmodule "tm.so"
...
loadmodule "registrar.so"
...
modparam("tm", "contacts_avp", "tm_contacts")
modparam("tm", "contact_flows_avp", "tm_contact_flows")
...
modparam("registrar", "use_path", 1)
modparam("registrar", "path_mode", 2)
modparam("registrar", "outbound_mode", 2)
...
route[LOCATION] {
...
if (!lookup("location")) {
$var(rc) = $rc;
route(TOVOICEMAIL);
t_newtran();
switch ($var(rc)) {
case -1:
case -3:
send_reply("404", "Not Found");
exit;
case -2:
send_reply("405", "Method Not Allowed");
exit;
}
}
if (!t_load_contacts()) {
send_reply("500", "Server Internal Error");
exit;
}
if (!t_next_contacts()) {
send_reply("500", "Server Internal Error");
exit;
}
t_on_failure("FAIL_OUTBOUND");
...
}
...
failure_route[FAIL_OUTBOUND] {
if (t_check_status("408|430")) {
if (!t_next_contact_flows() && !t_next_contacts()) {
send_reply("500", "Server Internal Error");
exit;
}
} else if (!t_next_contacts()) {
send_reply("500", "Server Internal Error");
exit;
}
t_on_failure("FAIL_OUTBOUND");
route(RELAY);
}
...