From be73b17d46fd22d3af367dfaf684a7a68d3df029 Mon Sep 17 00:00:00 2001
From: Mikayla Fischler <mikayla@ky8.io>
Date: Wed, 23 Mar 2022 16:17:58 -0400
Subject: [PATCH] RTU linking and requesting advertisement

---
 rtu/startup.lua        |  8 ++++++--
 scada-common/comms.lua | 17 ++++++++++++++---
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/rtu/startup.lua b/rtu/startup.lua
index 483aaee..ce6adb8 100644
--- a/rtu/startup.lua
+++ b/rtu/startup.lua
@@ -179,11 +179,15 @@ while true do
         end
     elseif event == "modem_message" then
         -- got a packet
-
+        local link_ref = { linked = linked }
         local packet = rtu_comms.parse_packet(p1, p2, p3, p4, p5)
-        rtu_comms.handle_packet(packet)
 
+        rtu_comms.handle_packet(packet, units, link_ref)
+
+        -- if linked, stop sending advertisements
+        linked = link_ref.linked
     elseif event == "terminate" then
+        print_ts("Exiting...\n")
         return
     end
 end
diff --git a/scada-common/comms.lua b/scada-common/comms.lua
index dfea4bf..bbcedde 100644
--- a/scada-common/comms.lua
+++ b/scada-common/comms.lua
@@ -34,8 +34,9 @@ RPLC_LINKING = {
 SCADA_MGMT_TYPES = {
     PING = 0,           -- generic ping
     SV_HEARTBEAT = 1,   -- supervisor heartbeat
-    RTU_HEARTBEAT = 2,  -- RTU heartbeat
-    RTU_ADVERT = 3      -- RTU capability advertisement
+    REMOTE_LINKED = 2,  -- remote device linked
+    RTU_ADVERT = 3,     -- RTU capability advertisement
+    RTU_HEARTBEAT = 4,  -- RTU heartbeat
 }
 
 RTU_ADVERT_TYPES = {
@@ -203,7 +204,7 @@ function rtu_comms(modem, local_port, server_port)
         return pkt
     end
 
-    local handle_packet = function(packet, units)
+    local handle_packet = function(packet, units, ref)
         if packet ~= nil then
             local protocol = packet.scada_frame.protocol()
 
@@ -222,6 +223,16 @@ function rtu_comms(modem, local_port, server_port)
                 end
             elseif protocol == PROTOCOLS.SCADA_MGMT then
                 -- SCADA management packet
+                if packet.type == SCADA_MGMT_TYPES.REMOTE_LINKED then
+                    -- acknowledgement
+                    ref.linked = true
+                elseif packet.type == SCADA_MGMT_TYPES.RTU_ADVERT then
+                    -- request for capabilities again
+                    send_advertisement(units)
+                else
+                    -- not supported
+                    log._warning("RTU got unexpected SCADA message type " .. packet.type, true)
+                end
             else
                 -- should be unreachable assuming packet is from parse_packet()
                 log._error("Illegal packet type " .. protocol, true)