Work on init code

storage-net/common.lua

@@ -8,6 +8,7 @@ mode                = "ConfigureMe"     -- The mode of function for this node
 networkid           = 0                 -- Unique ID for this network
 port_broadcast      = 42914             -- Port for M->S traffic
 port_return         = 42915             -- Port for S->M traffic
+packet_magic        = "ccstoragenet"    -- Just a random string
 
 -- This loads config.lua. See masterconfig.lua and slaveconfig.lua for example
 -- configurations.
@@ -15,8 +16,7 @@ require "config"
 
 -- Startup diagnostics
 print("Salt's CC Storage Net")
-print("Computer ID: " .. os.getComputerID())
+print("Computer " .. os.getComputerID() .. " configured as " .. mode)
-print("Computer " .. os.getComputerID() .. " running as " .. mode)
 
 -- Common globals
 modem = peripheral.find("modem") or error("No modem attached", 0)
@@ -31,32 +31,90 @@ function c_mainLoop(loopfunc)
         sleep(0.10)
     end
 end
--- Master functions
+function c_waitForMessage()
-function m_loop()
+    -- Waits for a message on the modem, timing out after 1 second
-    -- The main loop of the master server
-    -- Listen for packets on the return net. This has a timeout for events and stuff
     local timeout = os.startTimer(1)
     local event, side, channel, replyChannel, message, distance = os.pullEvent()
     if (event == "modem_message") then
-        print("Message received: " .. message)
+        if
+            (message["magic"] ~= packet_magic) or       -- Magic is required per packet spec
+            (not message["type"])                       -- Message type is required
+            then
+            print("Discarded nonconformant message")
+            return nil
+        end
+        return message
     end
+    return nil
+end
+function c_sendMessage(message)
+    -- Sends a message, either to the master or all slaves depending on mode
+    local msg = {
+        magic           = packet_magic,
+        networkid       = networkid,
+        sourceid        = os.getComputerID(),
+        --destid is optional
+    }
+    -- Override basic message object with args
+    for k,v in pairs(message) do
+        msg[k] = v
+    end
+    print("Transmitting message: " .. textutils.serialize(msg))
+    -- Transmit on different ports depending on mode
+    if (mode == "master") then
+        modem.transmit(port_broadcast, port_return, msg)
+    elseif (mode == "slave") then
+        modem.transmit(port_return, port_broadcast, msg)
+    end
+end
+-- Master functions
+function m_loop()
+    -- The main loop of the master server
+    -- Listen for packets on the return net
+    msg = c_waitForMessage()
+    if not msg then return end
     sleep(1)
 end
 -- Slave functions
 function s_loop()
     -- The main loop of any slave nodes
     -- Listen for packets from the master
-    local event, side, channel, replyChannel, message, distance = os.pullEvent("modem_message")
+    msg = c_waitForMessage()
+    if not msg then
+        print(".")
+        return
+    end
+    if (msg[type] == "ping") then
+        -- Respond to pings with pongs
+        print("Received ping")
+        c_sendMessage({type="pong"})
+    end
     sleep(1)
 end
 
 -- Application entrypoint
 function main ()
     if (mode == "master") then
+        print("Beginning initialization as master...")
         modem.open(port_return)
+
+        print("Pinging for slaves...")
+        c_sendMessage({type="ping"})
+        sleep(3)
+        local msg = true
+        while msg ~= nil do
+            msg = c_waitForMessage()
+            if (msg and msg[type] == "pong") then
+                print("Received pong from " .. msg["sourceid"])
+            end
+        end
+        print("Entering main loop")
         c_mainLoop(m_loop)
     elseif (mode == "slave") then
+        print("Beginning initialization as slave...")
         modem.open(port_broadcast)
+
+        print("Entering main loop")
         c_mainLoop(s_loop)
     else
         error("Invalid mode: " .. mode .. ", please configure this node appropriately", 0)