dns.lua hinzugefügt

dns.lua

@@ -0,0 +1,38 @@
+local event = require("event")
+local minitel = require("minitel")
+local computer = require("computer")
+
+local target = ...
+if not target then
+  io.stderr:write("Usage: resolve <hostname>\n")
+  return
+end
+
+local GATEWAY = "home1"
+local PORT = 5353
+
+-- eigenen Namen holen
+local f = io.open("/etc/hostname", "r")
+local me = f and f:read("*l") or "client"
+if f then f:close() end
+
+-- Anfrage senden
+minitel.usend(GATEWAY, PORT, "Q " .. target .. " " .. me)
+
+-- auf Antwort warten
+local deadline = computer.uptime() + 3
+while computer.uptime() < deadline do
+  local _, from, port, data = event.pull(deadline - computer.uptime(), "net_msg")
+  if port == PORT and type(data) == "string" then
+    local cmd, a, b = data:match("^(%S+)%s+(%S+)%s*(%S*)")
+    if cmd == "A" and a == target then
+      print(b)  -- b = Hardware-UUID
+      return
+    elseif cmd == "NX" and a == target then
+      print("NXDOMAIN: " .. target)
+      return
+    end
+  end
+end
+
+print("Timeout")