route{

	# initial sanity checks -- messages with
	# max_forwards==0, or excessively long requests
	if (!mf_process_maxfwd_header("10")) {
		sl_send_reply("483","Too Many Hops");
		break;
	};
	if ( msg:len > max_len ) {
		sl_send_reply("513", "Message too big");
		break;
	};


	#!! Nathelper
	if (nat_uac_test("3")){
		if (method == "REGISTER" || !search("^Record-Route:")){
			log("LOG:Someone trying to register from private IP, rewriting\n");
			fix_nated_contact(); # Rewtite contact with source IP of signalling
			if(method== "INVITE"){
				fix_nated_sdp("1"); # Add direction-active to SDP
			};
			force_rport();
			setflag(6);	
		};
	}else{
		fix_nated_contact();
	};
	
	
	# we record-route all messages -- to make sure that
	# subsequent messages will go through our proxy; that's
	# particularly good if upstream and downstream entities
	# use different transport protocol
	record_route();	
	# loose-route processing

	if (loose_route()) {
		t_relay();
		break;
	};

	# if the request is for other domain use UsrLoc
	# (in case, it does not work, use the following command
	# with proper names and addresses in it)
	if (uri==myself) {

		if (method=="REGISTER") {
			save("location");
			break;
		};
	};

	if (uri=~"sip:019[0-9]+@myserver.com") {
		  strip(1);
		  rewritehostport("1.2.3.4:5060");
		  t_relay();
		  break;
        }


	if (method=="INVITE") {
		fix_nated_sdp("3");
		append_hf("P-hint:Invite");
		# native SIP destinations are handled using our USRLOC DB
		if (!lookup("location")) {
			sl_send_reply("", "Connecting");
			break;
		};
	};
	
	 if (method=="ACK"){
		sl_send_reply("", "ACK");
		break;
	 };

	if (isflagset(6)){
		force_rtp_proxy();
		append_hf("P-hint:Flag6");
	}else{
		force_rtp_proxy();
		t_on_reply("1");
	};

	# forward to current uri now; use stateful forwarding; that
	# works reliably even if we forward from TCP to UDP
	if (!t_relay()) {
		sl_reply_error();
		break;
	};
}

# all incoming replies for t_onrepli-ed transactions enter here
onreply_route[1] {
	sdp_mangle_port("-12000");
	 if (isflagset(6) && status=~"2[0-9][0-9]"){
		append_hf("First Route");	
		fix_nated_contact();
		fix_nated_sdp("1");
		force_rtp_proxy();
	 } else if (status=~"2[0-9][0-9]"){
		if (uri=~"sip:019[0-9]+@myserver.com") {
		  append_hf("019");
		  fix_nated_contact();
		  fix_nated_sdp("3");
	        }
		else{
		  append_hf("2nd Route");
        	  fix_nated_contact();
		  fix_nated_sdp("2");
		  fix_nated_sdp("3");
		  force_rtp_proxy();
		}
	 };
}