[ComputerCraft] rednet sniffer

print("NetWork Swzitzer 1.0")
print("Press any key to exit")
local modem = peripheral.wrap("top") -- Whopper
local h = fs.open("nslog", fs.exists("nslog") and "a" or "w")
modem.open(65533)
modem.open(65535)
local weider = true
while weider do
    local event, keyside, sender, reply, packet, dist = os.pullEvent()
    if event == "modem_message" then
        str=textutils.serialize(packet).." DIST "..tostring(dist)
        print(str)
        h.writeLine(str)
    elseif event == "key" then
        print("Pressed key "..tostring(keyside))
        h.close()
        modem.closeAll()
        weider=false
    end
end