dnsclient.lua

local component=require("component")
local computer=require("computer")
local serial=require("serialization")
local event=require("event")
local fs=require("filesystem")
local modem=component.modem
modem.open(100)
local liste={}
local config
local found=false
function getTicks()
  return ((os.time() * 1000) / 60 /60) - 6000
end

function getServer()
  local t1=getTicks()
  local srun=true
  modem.broadcast(100, config["dnsserver"])
  while srun and not found do
    local t2=getTicks()
    if t2>t1+120 or t2<t1-99 then
      srun=false
    end
    _,_,_, port, _, command, addr, rname=event.pull(1,"modem_message")
    if port==100 and command=="req" and rname==config["dnsserver"] then
      found=true
     end
  end
  if found then
    liste[config["dnsserver"]]=addr
  else
    print("Kein DNS im Netz gefunden")
  end
end

function register()
  modem.send(liste[config[dnsserver]], 100, "set", myname)
end

function loadConfig()
  local file=io.open("/etc/dns.cfg")
  local text=file:read("*all")
  print(test)
  file:close()
  config=serial.unserialize(text)
end

function request(name)
  local t1=getTicks()
  local srun=true
  local found=false
  modem.send(liste[config["dnsserver"]], 100, name)
  while srun and not found do
    local t2=getTicks()
    if t2>t1+80 or t2<t1-79 then
      srun=false
    end
    _, _, _, port, _, command, addr, rname=event.pull("modem_message")
    if port==100 and command=="req" and rname==name then
      found=true
    end
  end
  return addr
end

function ns(name, n)
  if n or liste[name]==null or liste[name]=="" then
    return request(name)
  else
    return liste[name]
  end
end

function nsDaemon(event, name, n)
  computer.pushSignal("dnsReq", ns(name, n), name)
end

function init()
  os.sleep(1)
  loadConfig()
  if config["dnsserver"]~=config["computername"] then
    getServer()
    if found then
      register()
      event.listen("dnsGet", nsDaemon)
    end
  end
end

function start()
  init()
end