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# main routing logic

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");
                exit;
        };
        if (msg:len >=  2048 ) {
                sl_send_reply("513", "Message too big");
                exit;
        };

        # !! Nathelper
        # Special handling for NATed clients; first, NAT test is
        # executed: it looks for via!=received and RFC1918 addresses
        # in Contact (may fail if line-folding is used); also,
        # the received test should, if completed, should check all
        # vias for rpesence of received
        if (nat_uac_test("3")) {
                # Allow RR-ed requests, as these may indicate that
                # a NAT-enabled proxy takes care of it; unless it is
                # a REGISTER

                if (is_method("REGISTER") || !is_present_hf("Record-Route")) {
                    log("LOG: Someone trying to register from private IP, rewriting\n");

                    # This will work only for user agents that support symmetric
                    # communication. We tested quite many of them and majority is
                    # smart enough to be symmetric. In some phones it takes a configuration
                    # option. With Cisco 7960, it is called NAT_Enable=Yes, with kphone it is
                    # called "symmetric media" and "symmetric signalling".

                    fix_nated_contact(); # Rewrite contact with source IP of signalling
                    if ( is_method("INVITE") ) {
                        # fix_nated_sdp("1"); # Add direction=active to SDP
                        route(2);
                    };
                    force_rport(); # Add rport parameter to topmost Via
                    setbflag(6);    # Mark as NATed

                        # if you want sip nat pinging
                        # setbflag(8);
                };
        };

        # 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
        if (!is_method("REGISTER")) record_route();

        # subsequent messages withing a dialog should take the
        # path determined by record-routing
        if (loose_route()) {
                # mark routing logic in request
                append_hf("P-hint: rr-enforced\r\n");
                route(1);
                exit;
        };

        if (!uri==myself) {
                # mark routing logic in request
                append_hf("P-hint: outbound\r\n");
                route(1);
                exit;
        };

        # 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") {

                        # Uncomment this if you want to use digest authentication
                        if (!radius_www_authorize("")) {
                                www_challenge("", "1");
                                return;
                        };

                        save("location");
                        exit;
                };

                lookup("aliases");
                if (!uri==myself) {
                        append_hf("P-hint: outbound alias\r\n");
                        route(1);
                        exit;
                };

                # native SIP destinations are handled using our USRLOC DB
                if (!lookup("location")) {
                        sl_send_reply("404", "Not Found");
                        exit;
                };
        };
        append_hf("P-hint: usrloc applied\r\n");
        route(1);
}

route[1]
{
        # !! Nathelper
        if (uri=~"[@:](192\.168\.|10\.|172\.(1[6-9]|2[0-9]|3[0-1])\.)" && !search("^Route:")){
                sl_send_reply("479", "We don't forward to private IP addresses");
                exit;
        };

        # if client or server know to be behind a NAT, enable relay
        if (isbflagset(6)) {
                force_rtp_proxy();
        };

        # NAT processing of replies; apply to all transactions (for example,
        # re-INVITEs from public to private UA are hard to identify as
        # NATed at the moment of request processing); look at replies
        t_on_reply("1");

        # send it out now; use stateful forwarding as it works reliably
        # even for UDP2TCP
        if (!t_relay()) {
                sl_reply_error();
        };
}

# Routing block for external and internal
route[2]
{
        xlog("now going into route-2\n");
        fix_nated_sdp("1");
        t_on_failure("1");
        if (uri=~"sip:\\*353+@.*") {
                append_hf("mailbox:$tU\r\n");
                sl_send_reply("100", "Trying");
                forward("mars.greenfieldtech.net:6060");
        }
        if (uri=~"sip:\\*151+@.*" || uri=~"sip:\\*252+@.*") {
                sl_send_reply("100", "Trying");
                rewritehostport("mars.greenfieldtech.net:6060");
        };
        t_relay();
}

# !! Nathelper
onreply_route[1] {
        #xlog("now going into onreply_route-1\n");
        # NATed transaction ?
        if (isbflagset(6) && status =~ "(183)|2[0-9][0-9]") {
                fix_nated_contact();
                force_rtp_proxy();
        # otherwise, is it a transaction behind a NAT and we did not
        # know at time of request processing ? (RFC1918 contacts)
        } else if (nat_uac_test("1")) {
                fix_nated_contact();
        };
}

failure_route[1] {
      xlog("now going into fail route with  $T_reply_code\n");
      if(t_check_status("(404)|(500)")) {
           # call failed - relay to voice mail
           xlog("Now in the if block, with status $T_reply_code\n");
           route(3);
      }
      t_relay();
}

route[3] {
       sl_send_reply("100", "Trying");
       prefix("*353");
       t_relay("mars.greenfieldtech.net:6060");
       append_branch();
}