kamailio-basic-kemi-lua.lua

-- Kamailio - equivalent of routing blocks in Lua
--
-- KSR - the new dynamic object exporting Kamailio functions (kemi)
-- sr - the old static object exporting Kamailio functions
--

-- Relevant remarks:
--  * do not execute Lua 'exit' - that will kill Lua interpreter which is
--  embedded in Kamailio, resulting in killing Kamailio
--  * use KSR.x.exit() to trigger the stop of executing the script
--  * KSR.drop() is only marking the SIP message for drop, but doesn't stop
--  the execution of the script. Use KSR.x.exit() after it or KSR.x.drop()
--

kamailio = require "kamailio"

-- global variables corresponding to defined values (e.g., flags) in kamailio.cfg
FLT_ACC=1
FLT_ACCMISSED=2
FLT_ACCFAILED=3
FLT_NATS=5

FLB_NATB=6
FLB_NATSIPPING=7

-- SIP request routing
-- equivalent of request_route{}
function ksr_request_route()
  kamailio.process_request()
  return 1
end

-- wrapper around tm relay function
function ksr_route_relay()
	-- enable additional event routes for forwarded requests
	-- - serial forking, RTP relaying handling, a.s.o.
	if string.find("INVITE,BYE,SUBSCRIBE,UPDATE", KSR.pv.get("$rm")) then
		if KSR.tm.t_is_set("branch_route")<0 then
			KSR.tm.t_on_branch("ksr_branch_manage");
		end
	end
	if string.find("INVITE,SUBSCRIBE,UPDATE", KSR.pv.get("$rm")) then
		if KSR.tm.t_is_set("onreply_route")<0 then
			KSR.tm.t_on_reply("ksr_onreply_manage");
		end
	end

	if KSR.pv.get("$rm")=="INVITE" then
		if KSR.tm.t_is_set("failure_route")<0 then
			KSR.tm.t_on_failure("ksr_failure_manage");
		end
	end

	if KSR.tm.t_relay()<0 then
		KSR.sl.sl_reply_error();
	end
	KSR.x.exit();
end

-- RTPProxy control
function ksr_route_natmanage()
	if KSR.siputils.is_request()>0 then
		if KSR.siputils.has_totag()>0 then
			if KSR.rr.check_route_param("nat=yes")>0 then
				KSR.setbflag(FLB_NATB);
			end
		end
	end
	if (not (KSR.isflagset(FLT_NATS) or KSR.isbflagset(FLB_NATB))) then
		return 1;
	end

	KSR.rtpproxy.rtpproxy_manage("co");

	if KSR.siputils.is_request()>0 then
		if not KSR.siputils.has_totag() then
			if KSR.tmx.t_is_branch_route()>0 then
				KSR.rr.add_rr_param(";nat=yes");
			end
		end
	end
	if KSR.siputils.is_reply()>0 then
		if KSR.isbflagset(FLB_NATB) then
			KSR.nathelper.set_contact_alias();
		end
	end
	return 1;
end

-- URI update for dialog requests
function ksr_route_dlguri()
	if not KSR.isdsturiset() then
		KSR.nathelper.handle_ruri_alias();
	end
	return 1;
end

-- Manage outgoing branches
-- equivalent of branch_route[...]{}
function ksr_branch_manage()
	KSR.dbg("new branch [".. KSR.pv.get("$T_branch_idx")
				.. "] to ".. KSR.pv.get("$ru") .. "\n");
	ksr_route_natmanage();
	return 1;
end

-- Manage incoming replies
-- equivalent of onreply_route[...]{}
function ksr_onreply_manage()
	KSR.dbg("incoming reply\n");
	local scode = KSR.pv.get("$rs");
	if scode>100 and scode<299 then
		ksr_route_natmanage();
	end
	return 1;
end

-- Manage failure routing cases
-- equivalent of failure_route[...]{}
function ksr_failure_manage()
	ksr_route_natmanage();

	if KSR.tm.t_is_canceled()>0 then
		return 1;
	end
	return 1;
end

-- SIP response handling
-- equivalent of reply_route{}
function ksr_reply_route()
	KSR.info("===== response - from kamailio lua script\n");
	return 1;
end