Klaus Darilion writes:
- perform NAT traversal always, unless I know for sure that the client
does not support symmetric SIP. For doing NAT traversal you can either use fix_nated_contact() - which is not standard conform but works - or use the new add_contact_alias/handle_ruri_alias (kamailio 3.0: http://sip-router.org/docbook/sip-router/branch/master/modules_k/nathelper/n...)
here are the instructions in case someone missed them earlier.
-- juha
add_contact_alias()/handle_ruri_alias() usage example -----------------------------------------------------
supports re-use of tcp sessions between proxy and UAs. supports routing of requests to UAs behind NATs so that r-uri is always what UAs expect. proxying of media is not shown, but can be easily added.
NON_REGISTER_INITIAL_REQUESTS -----------------------------
- call alias_contact() for all non-register initial requests, which don't come from another proxy (which takes care of its own UAs).
- if you know that non-register initial request is going to another proxy, set TO_PROXY flag before relaying the request.
- in cases, where initial request may go to another proxy, but you are not sure about it, store the number of record-route headers in incoming request in an AVP that you can then later test in onreply route and find out, if next hop was a proxy.
route [NON_REGISTER_INITIAL_REQUESTS] {
if (!is_present_hf("Record-Route")) { route(ADD_CONTACT_ALIAS); }; ... if (I_KNOW_FOR_SURE_THAT_NEXT_HOP_IS_ANOTHER_PROXY) { setbflag("TO_PROXY"); };
if (NEXT_HOP_MAY_BE_ANOTHER_PROXY_BUT_I_DONT_KNOW_FOR_SURE) { $avp("rr_count") = $rr_count; }; t_on_reply("REPLY"); if (!t_relay()) ...
route [ADD_CONTACT_ALIAS] { if (!add_contact_alias()) { xlog("L_ERR", "Error in aliasing contact <$ct>\n"); send_reply("400", "Bad request"); exit; }; }
REGISTER_REQUESTS -----------------
- call fix_nated_register() on register requests, if registering ua is behind nat OR is using tcp.
route [REGISTER_REQUESTS] { ... if (isflagset(FROM_NATED) || (proto == TCP)) { fix_nated_register(); if (isflagset(FROM_NATED)) { setbflag("TO_NATED"); }; }; save("location"); ...
IN_DIALOG_REQUESTS ------------------
- call alias_contact() for all in-dialog requests that don't come from another proxy.
- call handle_ruri_alias() for all in-dialog requests before t_relaying them to UAs. next hop is an UA if loose_route() didn't set $du. if next hop is a proxy, set TO_PROXY flag.
route [IN_DIALOG_REQUESTS] {
if (@via[2] == "") { route(ADD_CONTACT_ALIAS); } loose_route(); if ($du == "") { handle_ruri_alias(); switch ($rc) { case -1: xlog("L_ERR", "Failed to handle alias of R-URI <$ru>\n"); send_reply("400", "Bad request"); exit; case 1: xlog("L_INFO", "Routing in-dialog $rm from <$fu> to <$du>\n"); break; case 2: xlog("L_INFO", "Routing in-dialog $rm from <$fu> to <$ru>\n"); break; }; } else { setbflag("TO_PROXY"); } t_on_reply("REPLY"); if (!t_relay()) { ...
REPLIES -------
- call add_contact_alias() on all replies except the ones that come from another proxy.
onreply_route [REPLY] {
if (!isbflagset("TO_PROXY") { if (is_avp_set("$avp(rr_count)")) { if ($rr_count == $avp(rr_count) + $rr_top_count) { route(ADD_CONTACT_ALIAS); }; } else { route(ADD_CONTACT_ALIAS); } } ...
NOTE ----
- do NOT call fix_nated_contact() on anything, because add_contact_alias() replaces it.