Telnet

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-- Aliases
IPAddress = Controls.IPAddress
UserName = Controls.UserName
Password = Controls.Password


-- Variables
TelnetActive = false  -- flag for the state of the telnet session
TelnetIsSetup = false  -- flag for the state of the telnet negotiation  
AttemptedLogin = false  -- flag for attempting to login but failed


-- Constants
Telnet = TcpSocket.New()  -- create new TCP object
Port = 23  -- port of the telnet server
EOL = "\r"  -- End Of Line character
IAC = 0xFF  -- telnet Interpret As Command character
TelSetResp = {  -- table of telnet setup options, these are examples of WONT options.  
  {cmd=0xFC,opt=0x18},
  {cmd=0xFC,opt=0x20},
  {cmd=0xFC,opt=0x23},
  {cmd=0xFC,opt=0x27},
  {cmd=0xFC,opt=0x03},
  {cmd=0xFC,opt=0x01},
  {cmd=0xFC,opt=0x1F},
  {cmd=0xFC,opt=0x05},
  {cmd=0xFC,opt=0x21}
}
UserPrompt = "login"  -- telnet user name prompt to look for during telnet login
PassPrompt = "Password"  -- telnet password prompt to look for during telnet login
LoggedInPrompt = "Login successful"  -- telnet logged in prompt to look for during telnet login
LoginFailPrompt = "Login incorrect"  -- telnet login fail prompt to look for during telnet login


-- Functions
function CredentialsEntered()  -- returns true if ip, user name and password have been entered
  return IPAddress.String~="" and UserName.String~="" and Password.String~=""
end

function TelnetSetup()  -- function to pack and send the do/dont/will/wont bits
  print("Setting up telnet session")
  local data={}
  for _,resp in ipairs(TelSetResp) do
    table.insert(data,string.pack("BBB",IAC,resp.cmd,resp.opt))
  end
  Telnet:Write(table.concat(data))
end

function TelnetAuth(rx)  -- function to look for user name and password prompts and send proper credentials
  if rx:match(UserPrompt) then print("Found UserPrompt") Telnet:Write(UserName.String..EOL) print("Sending: "..UserName.String)
  elseif rx:match(PassPrompt) then print("Found PassPrompt") Telnet:Write(Password.String..EOL) print("Sending: "..Password.String)
  end
end

function Disconnected()  -- function called when disconnected from the 
  TelnetActive = false
  TelnetIsSetup = false
  AttemptedLogin = false
end

function Connected()  -- function called when the telnet session is first active
  print("Telnet session active")
end

function TelnetIsConnected()  -- returns true when the telnet session flag is high
  return TelnetActive
end

function Connect()  -- function to connect the TCP socket
  if Telnet.IsConnected then Telnet:Disconnect() Disconnected() end
  if CredentialsEntered() then Telnet:Connect(IPAddress.String,Port) end
end

function Initialization()  -- function called at start of runtime
  print("Initializing plugin")
  Connect()
end

--Parsers
function ParseResponse()  -- function that reads and parses the TCP socket
  local rx=Telnet:Read(Telnet.BufferLength)  -- assign the contents of the buffer to a variable
  --print("RX: "..rx)
  if AttemptedLogin==false then
    if string.find(rx,LoggedInPrompt) then
      TelnetActive=true
      Connected()
    elseif string.find(rx,UserPrompt) or string.find(rx,PassPrompt) then
      print("Telnet session initiated")
      TelnetIsSetup=true
      TelnetAuth(rx)
    elseif string.find(rx,LoginFailPrompt) then 
      print("Telnet credentials incorrect")
      AttemptedLogin=true
    end
  end
  if TelnetIsSetup==false then TelnetSetup() end
end



-- TCP socket callbacks
Telnet.Connected=function()  -- function called when the TCP socket is connected
  print("Socket connected")
end

Telnet.Reconnect=function()  -- function called when the TCP socket is reconnected
  print("Socket reconnecting...")
end

Telnet.Closed=function() -- function called when the TCP socket is closed
  print("Socket closed")
  Disconnected()
end

Telnet.Error=function()  -- function called when the TCP socket has an error
  print("Socket error")
  Disconnected()
end

Telnet.Timeout=function()  -- function called when the TCP socket times out
  print("Socket timeout")
  Disconnected()
end

Telnet.Data=ParseResponse  -- ParseResponse is called when Telnet has data


-- EventHandlers
IPAddress.EventHandler = Connect
UserName.EventHandler = Connect
Password.EventHandler = Connect


-- Start at runtime
Initialization()  -- calls the Initialization function at the start of runtime