src/Maskable.hs

   1 module Maskable where
   2
   3 import Test.HUnit
   4
   5 import qualified Bit as B
   6 import IPv4Address
   7 import Maskbits
   8 import Octet
   9
  10 -- Any string of bits should be maskable by some number of netmask
  11 -- bits. The convention of the Maskable typeclass follows CIDR
  12 -- notation, where the number of mask bits (the number after the
  13 -- slash) denotes how many bits are reserved for the network.
  14 --
  15 -- So, a mask of 32 applied to an address of 127.0.0.1 will again
  16 -- return 127.0.0.1. Likewise, 31 mask bits applied to 127.0.0.1
  17 -- should return 127.0.0.0, since 127.0.0.1/31 matches both 127.0.0.0
  18 -- and 127.0.0.1. In this case, the final '0' or '1' is the host
  19 -- part of the address. The '127.0.0' is thus the network part.
  20 class Maskable a where
  21     apply_mask :: a -> Maskbits -> a
  22
  23
  24 instance Maskable Octet where
  25     apply_mask _ Maskbits.None = Octet.None
  26     apply_mask Octet.None _    = Octet.None
  27     apply_mask oct mask
  28         | mask == Eight = oct
  29         | mask == Seven = oct { b8 = B.Zero }
  30         | mask == Six = oct { b8 = B.Zero, b7 = B.Zero }
  31         | mask == Five = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero }
  32         | mask == Four = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero }
  33         | mask == Three = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero, b4 = B.Zero }
  34         | mask == Two = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero, b4 = B.Zero, b3 = B.Zero }
  35         | mask == One = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero, b4 = B.Zero, b3 = B.Zero, b2 = B.Zero }
  36         | mask == Zero = min_octet
  37         | otherwise = Octet.None
  38
  39
  40
  41 instance Maskable IPv4Address where
  42     apply_mask _ Maskbits.None = IPv4Address.None
  43     apply_mask addr mask
  44         | mask == ThirtyTwo = ipv4address_from_octets oct1 oct2 oct3 oct4
  45         | mask == ThirtyOne = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Seven)
  46         | mask == Thirty = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Six)
  47         | mask == TwentyNine = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Five)
  48         | mask == TwentyEight = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Four)
  49         | mask == TwentySeven = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Three)
  50         | mask == TwentySix = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Two)
  51         | mask == TwentyFive = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 One)
  52         | mask == TwentyFour = ipv4address_from_octets oct1 oct2 oct3 (min_octet)
  53         | mask == TwentyThree = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Seven) (min_octet)
  54         | mask == TwentyTwo = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Six) (min_octet)
  55         | mask == TwentyOne = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Five) (min_octet)
  56         | mask == Twenty = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Four) (min_octet)
  57         | mask == Nineteen = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Three) (min_octet)
  58         | mask == Eighteen = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Two) (min_octet)
  59         | mask == Seventeen = ipv4address_from_octets oct1 oct2 (apply_mask oct3 One) (min_octet)
  60         | mask == Sixteen = ipv4address_from_octets oct1 oct2 (min_octet) (min_octet)
  61         | mask == Fifteen = ipv4address_from_octets oct1 (apply_mask oct2 Seven) (min_octet) (min_octet)
  62         | mask == Fourteen = ipv4address_from_octets oct1 (apply_mask oct2 Six) (min_octet) (min_octet)
  63         | mask == Thirteen = ipv4address_from_octets oct1 (apply_mask oct2 Five) (min_octet) (min_octet)
  64         | mask == Twelve = ipv4address_from_octets oct1 (apply_mask oct2 Four) (min_octet) (min_octet)
  65         | mask == Eleven = ipv4address_from_octets oct1 (apply_mask oct2 Three) (min_octet) (min_octet)
  66         | mask == Ten = ipv4address_from_octets oct1 (apply_mask oct2 Two) (min_octet) (min_octet)
  67         | mask == Nine = ipv4address_from_octets oct1 (apply_mask oct2 One) (min_octet) (min_octet)
  68         | mask == Eight = ipv4address_from_octets oct1 (min_octet) (min_octet) (min_octet)
  69         | mask == Seven = ipv4address_from_octets (apply_mask oct1 Seven) (min_octet) (min_octet) (min_octet)
  70         | mask == Six = ipv4address_from_octets (apply_mask oct1 Six) (min_octet) (min_octet) (min_octet)
  71         | mask == Five = ipv4address_from_octets (apply_mask oct1 Five) (min_octet) (min_octet) (min_octet)
  72         | mask == Four =  ipv4address_from_octets (apply_mask oct1 Four) (min_octet) (min_octet) (min_octet)
  73         | mask == Three = ipv4address_from_octets (apply_mask oct1 Three) (min_octet) (min_octet) (min_octet)
  74         | mask == Two = ipv4address_from_octets (apply_mask oct1 Two) (min_octet) (min_octet) (min_octet)
  75         | mask == One = ipv4address_from_octets (apply_mask oct1 One) (min_octet) (min_octet) (min_octet)
  76         | mask == Zero = ipv4address_from_octets (min_octet) (min_octet) (min_octet) (min_octet)
  77         | otherwise = IPv4Address.None
  78         where
  79           oct1 = (octet1 addr)
  80           oct2 = (octet2 addr)
  81           oct3 = (octet3 addr)
  82           oct4 = (octet4 addr)
  83
  84
  85
  86 -- HUnit Tests
  87
  88 test_octet_mask1 :: Test
  89 test_octet_mask1 =
  90     TestCase $ assertEqual "The network bits of 255/4 should equal 240" oct2 (apply_mask oct1 Four)
  91     where
  92       oct1 = octet_from_int 255
  93       oct2 = octet_from_int 240
  94
  95
  96 test_octet_mask2 :: Test
  97 test_octet_mask2 =
  98     TestCase $ assertEqual "The network bits of 255/1 should equal 128" oct2 (apply_mask oct1 One)
  99     where
 100       oct1 = octet_from_int 255
 101       oct2 = octet_from_int 128
 102
 103
 104 maskable_tests :: [Test]
 105 maskable_tests = [ test_octet_mask1,
 106                    test_octet_mask2 ]