Something

route[3] {
        # ----------------------------------------------------------
        # INVITE Message Handler
        # ----------------------------------------------------------
        if (!allow_trusted()) {
                if (!proxy_authorize("","subscriber")) {
                        proxy_challenge("","0");
                        break;
                } else if (!check_from()) {
                        sl_send_reply("403", "Use From=ID");
                        break;
                };
                consume_credentials();
        };
        if (client_nat_test("3")) {
                setflag(7);
                force_rport();
                fix_nated_contact();
        };
        lookup("aliases");
        if (uri!=myself) {
                route(4);
                route(1);
                break;
        };
        if (avp_db_load("$ruri/username", "s:callfwd")) {
                setflag(22);
                avp_pushto("$ruri", "s:callfwd");
                route(6);
                break;
        };
        if (!lookup("location")) {
                 if (uri=~"^sip:0[1-9][0-9]{8}") { # Domestic PSTN 
                        #strip(1);
                        #prefix("61");
                        route(4);
                        route(5);
                        break;
                };
               sl_send_reply("404", "User Not Found");
                break;
        };

        if (avp_db_load("$ruri/username", "s:fwdbusy")) {
                if (!avp_check("s:fwdbusy", "eq/$ruri/i")) {
                        setflag(26);
                };
        };
        if (avp_db_load("$ruri/username", "s:fwdnoanswer")) {
                if (!avp_check("s:fwdnoanswer", "eq/$ruri/i")) {
                        setflag(27);
                };
        };
        log(1,"t on fail \n");
        t_on_failure("1");
        route(4);
        route(1);
}