## Kamailio - equivalent of routing blocks in Ruby
 ##
 ## KSR - the new dynamic object exporting Kamailio functions
 
 ## Relevant remarks:
 ## KSR.x.exit() is not exported in ruby as per KEMI docs, so we use native exit
 ## Module names are capitalised and referenced with double colons - e.g. it's KSR::HDR.append instead of KSR.hdr.append in other KEMI languages
 
 ## 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
 
 def ksr_request_route()
 
   # Per request initial checks
   ksr_route_reqinit()
 
   ksr_route_natdetect()
 
   if KSR.is_CANCEL() then
     if KSR::TM.t_check_trans() > 0 then
       ksr_route_relay()
     end
     return
   end
 
   ksr_route_withindlg()
 
   # Retransmissions
   if !KSR.is_ACK() then
     if KSR::TMX.t_precheck_trans() > 0 then
       KSR::TM.t_check_trans()
       return
     end
     return if KSR::TM.t_check_trans() == 0
   end
 
   # Auth
   ksr_route_auth()

   # Record routing for dialog forming requests (in case they are routed)
   KSR::HDR.remove("Route")
   if KSR.is_method_in("IS") then
     KSR::RR.record_route()
   end
 
   KSR.setflag($FLT_ACC) if KSR.is_INVITE()
 
   # Dispatch to external
   ksr_route_sipout()
 
   # Registrations
   ksr_route_registrar()
 
   # USRLOC
   ksr_route_location()
 
   return
 end
 
 def ksr_route_reqinit()
   if KSR::COREX.has_user_agent() > 0 then
     ua = KSR::PV.gete("$ua");

     if ua.include? 'friendly' or ua.include? 'scanner'
         or ua.include? 'sipcli' or ua.include? 'sipvicious' then

       KSR::SL.sl_send_reply(200, "OK");
       exit
     end
   end
 
   if KSR::MAXFWD.process_maxfwd(10) < 0 then
     KSR::SL.sl_send_reply(483,"Too Many Hops");
     exit
   end
 
   if KSR.is_OPTIONS() and KSR.is_myself_ruri() and KSR::COREX.has_ruri_user() < 0 then
     KSR::SL.sl_send_reply(200, "Keepalive");
     exit
   end
 
   if KSR::SANITY.sanity_check(1511, 7) < 0 then

     KSR.err("Malformed SIP message from #{KSR::PV.get('$si')}:#{KSR::PV.get('$sp')}\n");

     exit
   end
 end
 
 def ksr_route_relay()
   if KSR.is_method_in("IBSU") then
     if KSR::TM.t_is_set("branch_route") < 0 then
       KSR::TM.t_on_branch("ksr_branch_manage")
     end
   end
   if KSR.is_method_in("ISU") then
     if KSR::TM.t_is_set("onreply_route") < 0 then
       KSR::TM.t_on_reply("ksr_onreply_manage")
     end
   end 
 
   if KSR.is_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
   exit
 end
 
 def ksr_route_withindlg()
   return if KSR::SIPUTILS.has_totag() < 0
 
   if KSR::RR.loose_route() > 0 then
     ksr_route_dlguri()
     if KSR.is_BYE() then
       KSR.setflag($FLT_ACC)
       KSR.setflag($FLT_ACCFAILED)
     elsif KSR.is_ACK() then
       ksr_route_natmanage()
     elsif KSR.is_NOTIFY() then
       KSR::RR.record_route()
     end
     ksr_route_relay()
     exit
   end
 
   if KSR.is_ACK() then
     if KSR::TM.t_check_trans() > 0 then
       ksr_route_relay()
       exit
     else
       exit
     end
   end
   #KSR.info("404ing within dialog")
   KSR::SL.sl_send_reply(404, "Not here");
   exit
 end
 
 # IP authorization and user authenticaton
 def ksr_route_auth()
 	if !KSR.is_REGISTER() then
     # source IP allowed
     return if KSR::PERMISSIONS.allow_source_address(1).to_i > 0
 	end
 
 	if KSR.is_REGISTER() or KSR.is_myself_furi() then
 		# auth requests
     if KSR::AUTH_DB.auth_check(KSR::PV.get("$fd"), "subscriber", 1).to_i < 0 then
 			KSR::AUTH.auth_challenge(KSR::PV.get("$fd"), 0)
 			exit
     end
 		# user authenticated - remove auth header
 		KSR::AUTH.consume_credentials() if !KSR.is_method_in("RP")
 	end
 
 	# if caller is not local subscriber, then check if it calls
 	# a local destination, otherwise deny, not an open relay here
 	if !KSR.is_myself_furi() && !KSR.is_myself_ruri() then
 		KSR::SL.sl_send_reply(403,"Not relaying")
 		exit
   end
 
 	return
 end
 
 def ksr_route_natdetect()
   KSR.force_rport()
   if KSR::NATHELPER.nat_uac_test(19) > 0 then
     if KSR.is_REGISTER() then
       KSR::NATHELPER.fix_nated_register()
     elsif KSR::SIPUTILS.is_first_hop() > 0 then
       KSR::NATHELPER.set_contact_alias()
     end
     KSR.setflag($FLT_NATS)
   end
   return
 end
 
 def 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.info("Natmanage - nat=yes")
         KSR.setbflag($FLB_NATB)
       end
     end
   end
   #KSR.info("Natmange - returning if NAT flags set")
   return if !KSR.isflagset($FLT_NATS) and !KSR.isbflagset($FLB_NATB)
   #KSR.info("Natmanage - RTPPROXY from here on")
   KSR::RTPPROXY::RTPPROXY_manage("co");
 
   if KSR::SIPUTILS.is_request() > 0 then
     if !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
 end
 
 def ksr_route_dlguri()
   KSR::NATHELPER.handle_ruri_alias() if !KSR.isdsturiset() 
 	return
 end
 
 def ksr_branch_manage()
 	KSR.dbg("new branch [#{KSR::PV.get("$T_branch_idx")}] to #{KSR::PV.get("$ru")}\n")
 	ksr_route_natmanage()
 	return
 end
 
 def ksr_onreply_manage()
   scode = KSR::PV.get("$rs");
   KSR.dbg("Reply status code is #{scode}")
 	ksr_route_natmanage() if scode > 100 and scode <= 299
 	return
 end
 
 def ksr_reply_route()
   #scode = KSR::PV.get("$rs");
   return
 end
 
 def ksr_onsend_route()
   return
 end
 
 def ksr_failure_manage()
 	ksr_route_natmanage()
 	return if KSR::TM.t_is_canceled() > 0
 	return
 end
 
 def ksr_dialog_event(evname)
   KSR.info("===== dialog module triggered event: #{evname}");
   return
 end
 
 def ksr_tm_event(evname)
   KSR.info("===== TM module triggered event: #{evname}");
   return
 end
 
 def ksr_route_sipout()
   return if KSR.is_myself_ruri()
   KSR::HDR.append("P-Hint: outbound\r\n")
   ksr_route_relay()
   exit
 end
 
 def ksr_route_registrar()
 	return if !KSR.is_REGISTER()
 	if KSR.isflagset($FLT_NATS) then
 		KSR.setbflag($FLB_NATB)
 		# do SIP NAT pinging
     KSR.setbflag($FLB_NATSIPPING)
   end
   KSR.info("saving loc")
 	if KSR::REGISTRAR.save("location", 0).to_i < 0 then
 		KSR::SL.sl_reply_error()
   end
 	exit
 end
 
 def ksr_route_location()
   rc = KSR::REGISTRAR.lookup("location").to_i
   if rc < 0 then
     KSR::TM.t_newtran()
     if rc == -1 or rc == -3 then
       KSR::SL.sl_send_reply(404, "Not Found")
 			exit
     elsif rc == -2 then
 			KSR::SL.sl_send_reply(405, "Method Not Allowed")
 			exit
 		end
   end
 
 	# when routing via usrloc, log the missed calls also
 	KSR.setflag($FLT_ACCMISSED) if KSR.is_INVITE()
 
 	ksr_route_relay()
 	exit

 end