Program to pwn rednet comunications

wiredolphin.lua

-- Program to pwn rednet comunications
-- Options
-- WireDoplphin replay   - prompt repeating coms with custom message & sender ids
-- WireDoplphin listen   - just listen and display comunications
-- TODO
-- add listening at the same time as repeating
-- more commandline options (gnu standered parsing?)
-- log how meny messages from every computer id sent and what spam was filtered

local helptext = "Usage: WireDoplphin <option>\noptions are:\nreplay   - prompt repeating coms with custom message & sender ids\nlisten   - just listen and display comunications"

-- Manage args
local args = { ... }

if #args ~= 1 then
  print(helptext)
  return
end


-- Simple config variables
local VERSION = "WireDoplphin v0.3"
local logfile = "WireDoplphin.log"
local ignoreCount = 30 -- allow for 30 of the same message (set to 0 for no filter)

-- Variables
local math = require("math") -- for random ids
local options = {} -- Store functions in here
local chan = 65535

-- If you get a lot of the same message start ignoring it
local messages = {}     -- store messages

-- filled in lower down
local choice
local newmsg
local id
local modem

local ReceivedMessages = {} -- Store messages we have already processed

-- Find a modem and wrap it to the modem peripheral
for n, m in ipairs(peripheral.getNames()) do
  if peripheral.getType(m) == "modem" then
    modem = peripheral.wrap(m)
    break
  end
end
-- If you did not find a modem error
if not modem then
  print("Failed to find modem.")
  return
end

-- Add custom filters here
local function passesFilter(msg)
  -- Check if the protocol is one char long
  if msg.sProtocol and #msg.sProtocol == 1 then
    return false
  end

  -- check if the message can be converted to a number
  local testNum = tonumber(msg.message)
  if testNum then
    return false
  end

  -- Make sure it is a rednet comunication
  if type(msg) ~= "table" then
    return false
  end

  -- Make sure it has all the required indexes in the table
  if not msg.nMessageID then return false end
  if not msg.nRecipient then return false end
  if not msg.message    then return false end

  -- Make sure they have valid message id's
  if ReceivedMessages[msg.nMessageID] then return false end

  -- Filters out repeating messages.

  -- If ignoreCount = 0 then don't bother
  if ignoreCount == 0 then return true end
  -- Create the message index if needed.
  if not messages[msg.message] then
    messages[msg.message] = 0
  end

  -- Add to the message index
  messages[msg.message] = messages[msg.message] + 1

  -- check to see if it has repeated too meny times
  if messages[msg.message] >= ignoreCount then
    return false
  end
  -- otherwise return true
  return true
end

-- Will be used later prolly
local function inTable(value, t)
  for k, indexVal in ipairs(t) do
    if value == indexVal then
      return true
    end
  end
  return false
end

-- Log stuff to a file
local function log(msg, filename)
  local f = fs.open(filename, "a")
  f.write(msg.."\n")
  f.close()
end

-- Get rednet messages
local function receive()
  -- In the rednet protocol replyChannel is the sender id
  while true do
    local _, _, _, replyChannel, msg = os.pullEvent("modem_message")
    if passesFilter(msg) then
      ReceivedMessages[msg.nMessageID] = true
      return replyChannel, msg
    end
  end
end

-- Yeah i'm a pythoner, fight me
local function input(prompt)
  if prompt then
    io.write(prompt)
  end
  return io.read()
end

-- functions (one for every option)
function options.listen()
  while true do
    local chan, msg = receive()
    print(textutils.serialise(msg))
  end
end

function options.replay()
  while true do
    local respchan, msg = receive()
    -- Prompt the user to replay the message
    print(textutils.serialise(msg))
    choice = input("replay (y/n/q): ")

    if choice == "y" then
      -- ask if they want to change the message
      newmsg = input("New message: ")
      if newmsg ~= "" then
        msg.message = newmsg
      end

      -- ask if they want to spoof the sender id
      id = input("Sender id: ")
      id = tonumber(id)

      -- if it fails to convert to a number then leave it unchanged.
      if not id then
        -- Later i could make it listen in parallel on its computerid
        -- to get the response from the server.
        id = respchan
      end

      local nMessageID = math.random(1, 2147483647)
      ReceivedMessages[ nMessageID ] = true -- so we don't get our own messages
      msg.nMessageID = nMessageID -- so rednet accepts our message

      -- id is response channel, rednet likes it that way
      modem.transmit(chan, id, msg)
      print("Packet transmited")
    elseif choice == "q" then
      return
    end
  end
end

-- Check option
if not options[args[1]] then print(helptext) return end
-- Otherwise run
modem.open(chan)
print("Starting "..VERSION.."...")
options[args[1]]()
print("Goodbye, thank you for using "..VERSION)