#Nathelper
modparam("registrar", "nat_flag", 6)
modparam("nathelper", "natping_interval", 30) # Ping interval 30 s
modparam("nathelper", "ping_nated_only", 1)   # Ping only clients behind NAT



# -------------------------  request routing logic -------------------

# main routing logic

route{
	# initial sanity checks -- messages with
	# max_forwards==0, or excessively long requests
	if (!mf_process_maxfwd_header("10")) {
		log(1, "LOG: Too many hops\n");
		sl_send_reply("483","Too Many Hops");
		break;
	};

	/* ********* RR ********************************** */
	/* Do strict routing if route headers present */
	loose_route();

	log(1, "Incomming SIP Packet");

	if (nat_uac_test("3")) 
	{
		log(1, "LOG: We are behind NAT, oh boy \n");

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

		    	fix_nated_contact(); # Rewrite contact with source IP of signalling
				if (method == "INVITE") 
				{
					log(1, "LOG: We are Inviting from behind NAT, oh boy \n");
			        	fix_nated_sdp("1"); # Add direction=active to SDP
				};
		    	
			force_rport(); # Add rport parameter to topmost Via
		    	setflag(6);    # Mark as NATed
		};
	};

	if (method=="REGISTER") 
	{
		log(1, "Registration starte\n");
        	if (!www_authorize("mysipdomain.com", "subscriber" )) 
		{
            		# challenge if none or invalid credentials
	    		log(1, "We are not authorized");
            		www_challenge("mysipdomain.com" , "0");
            		break;
        	};
        	if (!save("location")) 
		{
            		sl_reply_error();
        	};
        	break;
    	};

    	if(!lookup("location")&& uri=~"\+?[1-9]{3}+@.*" )
    	{
		log(1,"Going for route 10");
	        route(10);
	        break;
    	}
 
}



route[10]
{
       # !! 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");
	    	break;
        };
	
	# if client or server know to be behind a NAT, enable relay
	if (isflagset(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");

       
      	#check for authorization
      	if (!( method==ACK | method=="CANCEL" )) 
	{
                if (!proxy_authorize( "mysipdomain.com", "subscriber")) 
		{
                        proxy_challenge( "mysipdomain.com" /* realm */, "0" /* no qop */ );
                        break;
                # let's check from=id ... avoids accounting confusion
                } 
		else if (method=="INVITE" & !check_from()) 
		{
                        log(1,"LOG: From Cheating attempt\n");
                        sl_send_reply("403", "That is ugly -- use From=id next time (gw)");
                        break;
                };
        };

	#forward to asterisk for getting out a here
	if(~uri=~"sip:\+")
	{
		log(1, "Rewriting + prefix with 00");
		strip(1);
		prefix("00");
	}
	
	#exec_dset("/usr/local/ser/scripts/loadbalance.sh");
	rewritehostport("sip.mysipdomain.com:5065");

	log(1, "LOG: *************************************************\n");
	log(1, "LOG: Exernal Call, forwarding thru * for Carrier stuff\n");
	log(1, "LOG: *************************************************\n");

	if (!t_relay()) 
	{
		sl_reply_error();
	    	break;
	};
}


# !! Nathelper
onreply_route[1] 
{
	# NATed transaction ?
	if (isflagset(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();
	    };
}