https://en.wikipedia.org/wiki/Man-in-the-middle_attack

firmware/controllers/lua/examples/man-in-the-middle.txt

@@ -1,11 +1,9 @@
 -- sometimes we want to cut a CAN bus and install rusEFI into that cut
 -- https://en.wikipedia.org/wiki/Man-in-the-middle_attack
 
-
 -- this controls onCanRx rate as well!
 setTickRate(300)
 
-
 ECU_BUS = 1
 -- really 'not ECU'
 TCU_BUS = 2
@@ -36,7 +34,35 @@ function arrayToString(arr)
 	return str
 end
 
+totalEcuMessages = 0
+totalTcuMessages = 0
+
+function printAndDrop(bus, id, dlc, data)
+    print('Dropping ' ..arrayToString(data))
+end
+
+function onAnythingFromECU(bus, id, dlc, data)
+    totalEcuMessages = totalEcuMessages + 1
+    txCan(TCU_BUS, id, 0, data) -- relay non-TCU message to TCU
+end
+
+function onAnythingFromTCU(bus, id, dlc, data)
+    totalTcuMessages = totalTcuMessages + 1
+    txCan(ECU_BUS, id, 0, data) -- relay non-ECU message to ECU
+end
+
+-- VAG Motor_1 just as example
+-- canRxAdd(ECU_BUS, 0x280, printAndDrop)
+
+-- last option: unconditional forward of all remaining messages
+canRxAddMask(ECU_BUS, 0, 0, onAnythingFromECU)
+canRxAddMask(TCU_BUS, 0, 0, onAnythingFromTCU)
+
+everySecondTimer = Timer.new()
 
 function onTick()
- -- empty 'onTick' until we make 'onTick' method optional
+    if everySecondTimer:getElapsedSeconds() > 1 then
+        everySecondTimer:reset()
+        print("Total from ECU " .. totalEcuMessages .. " from TCU " .. totalTcuMessages)
+    end
 end