Synnefo » snf-ganeti

{-| Implementation of the Ganeti network objects.

This is does not (yet) cover all methods that are provided in the

corresponding python implementation (network.py).

-}

{-

Copyright (C) 2011, 2012, 2013 Google Inc.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301, USA.

-}

module Ganeti.Network

  ( AddressPool(..)

  , createAddressPool

  , bitStringToBitVector

  , allReservations

  , getReservedCount

  , getFreeCount

  , isFull

  , getMap

  , networkIsValid

  ) where

import qualified Data.Vector.Unboxed as V

import Data.Maybe (isJust)

import Ganeti.Objects

-- | An address pool, holding a network plus internal and external

-- reservations.

data AddressPool = AddressPool { network :: Network,

                                 reservations :: V.Vector Bool,

                                 extReservations :: V.Vector Bool }

                                 deriving (Show)

-- | Create an address pool from a network.

createAddressPool :: Network -> Maybe AddressPool

createAddressPool n

  | networkHasPool n =

      let res = maybeStr2BitVec $ networkReservations n

          ext_res = maybeStr2BitVec $ networkExtReservations n

      in  Just AddressPool { reservations = res

                           , extReservations = ext_res

                           , network = n }

  | otherwise = Nothing

-- | Checks the consistency of the network object. So far, only checks the

-- length of the reservation strings.

networkHasPool :: Network -> Bool

networkHasPool = isJust . networkNetwork

-- | Checks the consistency of the network object. So far, only checks the

-- length of the reservation strings.

networkIsValid :: Network -> Bool

networkIsValid n =

  sameLength (networkReservations n) (networkExtReservations n)

-- | Checks if two maybe strings are both nothing or of equal length.

sameLength :: Maybe String -> Maybe String -> Bool

sameLength Nothing Nothing = True

sameLength (Just s1) (Just s2) = length s1 == length s2

sameLength _ _ = False

-- | Converts a maybe bit string to a bit vector. Returns an empty bit vector on

-- nothing.

maybeStr2BitVec :: Maybe String -> V.Vector Bool

maybeStr2BitVec (Just s) = bitStringToBitVector s

maybeStr2BitVec Nothing = V.fromList ([]::[Bool])

-- | Converts a string to a bit vector. The character '0' is interpreted

-- as 'False', all others as 'True'.

bitStringToBitVector :: String -> V.Vector Bool

bitStringToBitVector = V.fromList . map (/= '0')

-- | Get a bit vector of all reservations (internal and external) combined.

allReservations :: AddressPool -> V.Vector Bool

allReservations a = V.zipWith (||) (reservations a) (extReservations a)

-- | Get the count of reserved addresses.

getReservedCount :: AddressPool -> Int

getReservedCount = V.length . V.filter (== True) . allReservations

-- | Get the count of free addresses.

getFreeCount :: AddressPool -> Int

getFreeCount = V.length . V.filter (== False) . allReservations

-- | Check whether the network is full.

isFull :: AddressPool -> Bool

isFull = V.and . allReservations

-- | Return a textual representation of the network's occupation status.

getMap :: AddressPool -> String

getMap = V.toList . V.map mapPixel . allReservations

  where mapPixel c = if c then 'X' else '.'