src/IPv4Address.hs

   1 module IPv4Address(
   2   IPv4Address(..),
   3   ipv4address_properties,
   4   ipv4address_tests,
   5   most_sig_bit_different )
   6 where
   7
   8 import Data.Word (Word32)
   9
  10 import Test.Tasty ( TestTree, testGroup )
  11 import Test.Tasty.HUnit ( (@?=), testCase )
  12 import Test.Tasty.QuickCheck (
  13   Arbitrary( arbitrary ),
  14   Gen,
  15   Property,
  16   (==>),
  17   testProperty )
  18
  19 import Maskable ( Maskable( apply_mask) )
  20 import Maskbits (
  21   Maskbits(
  22     Zero, One, Two, Three, Four, Five, Six, Seven, Eight,
  23     Nine, Ten, Eleven, Twelve, Thirteen, Fourteen, Fifteen, Sixteen,
  24     Seventeen, Eighteen, Nineteen, Twenty, TwentyOne, TwentyTwo, TwentyThree,
  25     TwentyFour, TwentyFive, TwentySix, TwentySeven, TwentyEight, TwentyNine,
  26     Thirty, ThirtyOne, ThirtyTwo ) )
  27 import Octet ( Octet( b1, b2, b3, b4, b5, b6, b7, b8) )
  28
  29 data IPv4Address =
  30   IPv4Address { octet1 :: Octet,
  31                 octet2 :: Octet,
  32                 octet3 :: Octet,
  33                 octet4 :: Octet }
  34     deriving (Eq, Ord)
  35
  36
  37 instance Show IPv4Address where
  38   show addr = concat [(show oct1) ++ ".",
  39                       (show oct2) ++ ".",
  40                       (show oct3) ++ ".",
  41                       (show oct4)]
  42       where
  43         oct1 = (octet1 addr)
  44         oct2 = (octet2 addr)
  45         oct3 = (octet3 addr)
  46         oct4 = (octet4 addr)
  47
  48
  49 instance Arbitrary IPv4Address where
  50   arbitrary = do
  51     oct1 <- arbitrary :: Gen Octet
  52     oct2 <- arbitrary :: Gen Octet
  53     oct3 <- arbitrary :: Gen Octet
  54     oct4 <- arbitrary :: Gen Octet
  55     return (IPv4Address oct1 oct2 oct3 oct4)
  56
  57
  58
  59 instance Maskable IPv4Address where
  60
  61   apply_mask addr mask bit =
  62    apply_mask' mask
  63    where
  64      oct1 = octet1 addr
  65      oct2 = octet2 addr
  66      oct3 = octet3 addr
  67      oct4 = octet4 addr
  68
  69      -- A copy of 'addr' with the fourth octet zeroed (or oned).
  70      new_addr1 = addr { octet4 = (apply_mask oct4 Zero bit) }
  71
  72      -- Likewise for new_addr1's third octet.
  73      new_addr2 = new_addr1 { octet3 = (apply_mask oct3 Zero bit) }
  74
  75      -- And new_addr2's second octet.
  76      new_addr3 = new_addr2 { octet2 = (apply_mask oct2 Zero bit) }
  77
  78      -- This helper function allows us to pattern-match cleanly.
  79      apply_mask' :: Maskbits -> IPv4Address
  80
  81      apply_mask' ThirtyTwo = addr
  82
  83      apply_mask' ThirtyOne = addr { octet4 = (apply_mask oct4 Seven bit) }
  84
  85      apply_mask' Thirty =
  86        addr { octet4 = (apply_mask oct4 Six bit) }
  87
  88      apply_mask' TwentyNine =
  89        addr { octet4 = (apply_mask oct4 Five bit) }
  90
  91      apply_mask' TwentyEight =
  92        addr { octet4 = (apply_mask oct4 Four bit) }
  93
  94      apply_mask' TwentySeven =
  95        addr { octet4 = (apply_mask oct4 Three bit) }
  96
  97      apply_mask' TwentySix =
  98        addr { octet4 = (apply_mask oct4 Two bit) }
  99
 100      apply_mask' TwentyFive =
 101        addr { octet4 = (apply_mask oct4 One bit) }
 102
 103      apply_mask' TwentyFour = new_addr1
 104
 105      apply_mask' TwentyThree =
 106        new_addr1 { octet3 = (apply_mask oct3 Seven bit) }
 107
 108      apply_mask' TwentyTwo =
 109        new_addr1 { octet3 = (apply_mask oct3 Six bit) }
 110
 111      apply_mask' TwentyOne =
 112        new_addr1 { octet3 = (apply_mask oct3 Five bit) }
 113
 114      apply_mask' Twenty =
 115        new_addr1 { octet3 = (apply_mask oct3 Four bit) }
 116
 117      apply_mask' Nineteen =
 118        new_addr1 { octet3 = (apply_mask oct3 Three bit) }
 119
 120      apply_mask' Eighteen =
 121        new_addr1 { octet3 = (apply_mask oct3 Two bit) }
 122
 123      apply_mask' Seventeen =
 124        new_addr1 { octet3 = (apply_mask oct3 One bit) }
 125
 126      apply_mask' Sixteen =
 127        new_addr2
 128
 129      apply_mask' Fifteen =
 130        new_addr2 { octet2 = (apply_mask oct2 Seven bit) }
 131
 132      apply_mask' Fourteen =
 133        new_addr2 { octet2 = (apply_mask oct2 Six bit) }
 134
 135      apply_mask' Thirteen =
 136        new_addr2 { octet2 = (apply_mask oct2 Five bit) }
 137
 138      apply_mask' Twelve =
 139        new_addr2 { octet2 = (apply_mask oct2 Four bit) }
 140
 141      apply_mask' Eleven =
 142        new_addr2 { octet2 = (apply_mask oct2 Three bit) }
 143
 144      apply_mask' Ten =
 145        new_addr2 { octet2 = (apply_mask oct2 Two bit) }
 146
 147      apply_mask' Nine =
 148        new_addr2 { octet2 = (apply_mask oct2 One bit) }
 149
 150      apply_mask' Eight =
 151        new_addr3 { octet2 = (apply_mask oct2 Zero bit) }
 152
 153      apply_mask' Seven =
 154        new_addr3 { octet1 = (apply_mask oct1 Seven bit) }
 155
 156      apply_mask' Six =
 157        new_addr3 { octet1 = (apply_mask oct1 Six bit) }
 158
 159      apply_mask' Five =
 160        new_addr3 { octet1 = (apply_mask oct1 Five bit) }
 161
 162      apply_mask' Four =
 163        new_addr3 { octet1 = (apply_mask oct1 Four bit) }
 164
 165      apply_mask' Three =
 166        new_addr3 { octet1 = (apply_mask oct1 Three bit) }
 167
 168      apply_mask' Two =
 169        new_addr3 { octet1 = (apply_mask oct1 Two bit) }
 170
 171      apply_mask' One =
 172        new_addr3 { octet1 = (apply_mask oct1 One bit) }
 173
 174      apply_mask' Zero =
 175        new_addr3 { octet1 = (apply_mask oct1 Zero bit) }
 176
 177
 178 instance Bounded IPv4Address where
 179   -- | The minimum possible IPv4 address, 0.0.0.0.
 180   minBound = IPv4Address minBound minBound minBound minBound
 181
 182   -- | The maximum possible IPv4 address, 255.255.255.255.
 183   maxBound = IPv4Address maxBound maxBound maxBound maxBound
 184
 185
 186
 187
 188 instance Enum IPv4Address where
 189   -- | Convert an 'Int' @x@ to an 'IPv4Address'. Each octet of @x@ is
 190   --   right-shifted by the appropriate number of bits, and the fractional
 191   --   part is dropped.
 192   toEnum y =
 193     IPv4Address oct1 oct2 oct3 oct4
 194     where
 195       -- Convert the input Int to a Word32 before we proceed. On x86,
 196       -- the Int that we get could be negative (half of all IP
 197       -- addresses correspond to negative numbers), and then the magic
 198       -- below doesn't work. The Word32 type is unsigned, so we do the
 199       -- math on that and then convert everything back to Int later on
 200       -- once we have four much-smaller non-negative numbers.
 201       x = fromIntegral y :: Word32
 202
 203       -- Chop off the higher octets. x1 = x `mod` 2^32, would be
 204       -- redundant.
 205       x2 = x `mod` 2^(24 :: Integer)
 206       x3 = x `mod` 2^(16 :: Integer)
 207       x4 = (fromIntegral $ x `mod` 2^(8  :: Integer)) :: Int
 208       -- Perform right-shifts. x4 doesn't need a shift.
 209       shifted_x1 = (fromIntegral $ x `quot` 2^(24 :: Integer)) :: Int
 210       shifted_x2 = (fromIntegral $ x2 `quot` 2^(16 :: Integer)) :: Int
 211       shifted_x3 = fromIntegral $ x3 `quot` 2^(8 :: Integer) :: Int
 212       oct1 = toEnum shifted_x1 :: Octet
 213       oct2 = toEnum shifted_x2 :: Octet
 214       oct3 = toEnum shifted_x3 :: Octet
 215       oct4 = toEnum x4 :: Octet
 216
 217   -- | Convert @addr@ to an 'Int' by converting each octet to an 'Int'
 218   --   and shifting the result to the left by 0,8.16, or 24 bits.
 219   fromEnum addr =
 220     (shifted_oct1) + (shifted_oct2) + (shifted_oct3) + oct4
 221     where
 222       oct1 = fromEnum (octet1 addr)
 223       oct2 = fromEnum (octet2 addr)
 224       oct3 = fromEnum (octet3 addr)
 225       oct4 = fromEnum (octet4 addr)
 226       shifted_oct1 = oct1 * 2^(24 :: Integer)
 227       shifted_oct2 = oct2 * 2^(16 :: Integer)
 228       shifted_oct3 = oct3 * 2^(8 :: Integer)
 229
 230 -- | Given two addresses, find the number of the most significant bit
 231 --   where they differ. If the addresses are the same, return
 232 --   Maskbits.Zero.
 233 most_sig_bit_different :: IPv4Address -> IPv4Address -> Maskbits
 234 most_sig_bit_different addr1 addr2
 235   | addr1 == addr2 = Maskbits.Zero
 236   | m1  /= n1  = Maskbits.One
 237   | m2  /= n2  = Two
 238   | m3  /= n3  = Three
 239   | m4  /= n4  = Four
 240   | m5  /= n5  = Five
 241   | m6  /= n6  = Six
 242   | m7  /= n7  = Seven
 243   | m8  /= n8  = Eight
 244   | m9  /= n9  = Nine
 245   | m10 /= n10 = Ten
 246   | m11 /= n11 = Eleven
 247   | m12 /= n12 = Twelve
 248   | m13 /= n13 = Thirteen
 249   | m14 /= n14 = Fourteen
 250   | m15 /= n15 = Fifteen
 251   | m16 /= n16 = Sixteen
 252   | m17 /= n17 = Seventeen
 253   | m18 /= n18 = Eighteen
 254   | m19 /= n19 = Nineteen
 255   | m20 /= n20 = Twenty
 256   | m21 /= n21 = TwentyOne
 257   | m22 /= n22 = TwentyTwo
 258   | m23 /= n23 = TwentyThree
 259   | m24 /= n24 = TwentyFour
 260   | m25 /= n25 = TwentyFive
 261   | m26 /= n26 = TwentySix
 262   | m27 /= n27 = TwentySeven
 263   | m28 /= n28 = TwentyEight
 264   | m29 /= n29 = TwentyNine
 265   | m30 /= n30 = Thirty
 266   | m31 /= n31 = ThirtyOne
 267   | m32 /= n32 = ThirtyTwo
 268   | otherwise  = Maskbits.Zero
 269   where
 270     m1  = (b1 oct1a)
 271     m2  = (b2 oct1a)
 272     m3  = (b3 oct1a)
 273     m4  = (b4 oct1a)
 274     m5  = (b5 oct1a)
 275     m6  = (b6 oct1a)
 276     m7  = (b7 oct1a)
 277     m8  = (b8 oct1a)
 278     m9  = (b1 oct2a)
 279     m10 = (b2 oct2a)
 280     m11 = (b3 oct2a)
 281     m12 = (b4 oct2a)
 282     m13 = (b5 oct2a)
 283     m14 = (b6 oct2a)
 284     m15 = (b7 oct2a)
 285     m16 = (b8 oct2a)
 286     m17 = (b1 oct3a)
 287     m18 = (b2 oct3a)
 288     m19 = (b3 oct3a)
 289     m20 = (b4 oct3a)
 290     m21 = (b5 oct3a)
 291     m22 = (b6 oct3a)
 292     m23 = (b7 oct3a)
 293     m24 = (b8 oct3a)
 294     m25 = (b1 oct4a)
 295     m26 = (b2 oct4a)
 296     m27 = (b3 oct4a)
 297     m28 = (b4 oct4a)
 298     m29 = (b5 oct4a)
 299     m30 = (b6 oct4a)
 300     m31 = (b7 oct4a)
 301     m32 = (b8 oct4a)
 302     oct1a = (octet1 addr1)
 303     oct2a = (octet2 addr1)
 304     oct3a = (octet3 addr1)
 305     oct4a = (octet4 addr1)
 306     n1  = (b1 oct1b)
 307     n2  = (b2 oct1b)
 308     n3  = (b3 oct1b)
 309     n4  = (b4 oct1b)
 310     n5  = (b5 oct1b)
 311     n6  = (b6 oct1b)
 312     n7  = (b7 oct1b)
 313     n8  = (b8 oct1b)
 314     n9  = (b1 oct2b)
 315     n10 = (b2 oct2b)
 316     n11 = (b3 oct2b)
 317     n12 = (b4 oct2b)
 318     n13 = (b5 oct2b)
 319     n14 = (b6 oct2b)
 320     n15 = (b7 oct2b)
 321     n16 = (b8 oct2b)
 322     n17 = (b1 oct3b)
 323     n18 = (b2 oct3b)
 324     n19 = (b3 oct3b)
 325     n20 = (b4 oct3b)
 326     n21 = (b5 oct3b)
 327     n22 = (b6 oct3b)
 328     n23 = (b7 oct3b)
 329     n24 = (b8 oct3b)
 330     n25 = (b1 oct4b)
 331     n26 = (b2 oct4b)
 332     n27 = (b3 oct4b)
 333     n28 = (b4 oct4b)
 334     n29 = (b5 oct4b)
 335     n30 = (b6 oct4b)
 336     n31 = (b7 oct4b)
 337     n32 = (b8 oct4b)
 338     oct1b = (octet1 addr2)
 339     oct2b = (octet2 addr2)
 340     oct3b = (octet3 addr2)
 341     oct4b = (octet4 addr2)
 342
 343
 344 -- Test lists.
 345 ipv4address_tests :: TestTree
 346 ipv4address_tests =
 347   testGroup "IPv4 Address Tests" [
 348     test_enum,
 349     test_maxBound,
 350     test_minBound,
 351     test_most_sig_bit_different1,
 352     test_most_sig_bit_different2,
 353     test_ord_instance1,
 354     test_ord_instance2,
 355     test_ord_instance3,
 356     test_ord_instance4,
 357     test_to_enum ]
 358
 359 ipv4address_properties :: TestTree
 360 ipv4address_properties =
 361   testGroup
 362     "IPv4 Address Properties "
 363     [ prop_from_enum_to_enum_inverses ]
 364
 365 -- QuickCheck properties
 366 prop_from_enum_to_enum_inverses :: TestTree
 367 prop_from_enum_to_enum_inverses =
 368   testProperty "fromEnum and toEnum are inverses" prop
 369   where
 370     prop :: Int -> Property
 371     prop x =
 372       (0 <= x) && (x <= 2^(32 :: Integer) - 1) ==>
 373         fromEnum (toEnum x :: IPv4Address) == x
 374
 375 -- HUnit Tests
 376 mk_testaddr :: Int -> Int -> Int -> Int -> IPv4Address
 377 mk_testaddr a b c d =
 378   IPv4Address oct1 oct2 oct3 oct4
 379   where
 380     oct1 = toEnum a :: Octet
 381     oct2 = toEnum b :: Octet
 382     oct3 = toEnum c :: Octet
 383     oct4 = toEnum d :: Octet
 384
 385
 386 test_minBound :: TestTree
 387 test_minBound =
 388   testCase desc $ actual @?= expected
 389   where
 390     desc = "minBound should be 0.0.0.0"
 391     expected = mk_testaddr 0 0 0 0
 392     actual = minBound :: IPv4Address
 393
 394
 395 test_maxBound :: TestTree
 396 test_maxBound =
 397   testCase desc $ actual @?= expected
 398   where
 399     desc = "maxBound should be 255.255.255.255"
 400     expected = mk_testaddr 255 255 255 255
 401     actual = maxBound :: IPv4Address
 402
 403
 404 test_enum :: TestTree
 405 test_enum =
 406   testCase desc $ actual @?= expected
 407   where
 408     desc = "enumerating a /24 gives the correct addresses"
 409     expected = ["192.168.0." ++ (show x) | x <- [0..255::Int] ]
 410     lb = mk_testaddr 192 168 0 0
 411     ub = mk_testaddr 192 168 0 255
 412     actual = map show [lb..ub]
 413
 414
 415 test_most_sig_bit_different1 :: TestTree
 416 test_most_sig_bit_different1 =
 417   testCase desc $ actual @?= expected
 418   where
 419     desc = "10.1.1.0 and 10.1.0.0 differ in bit 24"
 420     addr1 = mk_testaddr 10 1 1 0
 421     addr2 = (mk_testaddr 10 1 0 0)
 422     expected = TwentyFour
 423     actual = most_sig_bit_different addr1 addr2
 424
 425
 426
 427 test_most_sig_bit_different2 :: TestTree
 428 test_most_sig_bit_different2 =
 429   testCase desc $ actual @?= expected
 430   where
 431     desc = "10.1.2.0 and 10.1.1.0 differ in bit 23"
 432     addr1 = mk_testaddr 10 1 2 0
 433     addr2 = mk_testaddr 10 1 1 0
 434     expected = TwentyThree
 435     actual = most_sig_bit_different addr1 addr2
 436
 437
 438 test_to_enum :: TestTree
 439 test_to_enum =
 440   testCase desc $ actual @?= expected
 441   where
 442     desc     = "192.168.0.0 in base-10 is 3232235520"
 443     expected = mk_testaddr 192 168 0 0
 444     -- We declare the big number as Word32 because otherwise, on x86,
 445     -- we get a warning that it's too big to fit in a 32-bit integer.
 446     -- Ultimately we convert it to a (negative) Int on those systems
 447     -- anyway, but the gymnastics declare our intent to the compiler.
 448     actual   = toEnum (fromIntegral (3232235520 :: Word32)) :: IPv4Address
 449
 450
 451 test_ord_instance1 :: TestTree
 452 test_ord_instance1 =
 453   testCase desc $ actual @?= expected
 454   where
 455     desc     = "127.0.0.0 is less than 127.0.0.1"
 456     addr1 = mk_testaddr 127 0 0 0
 457     addr2 = mk_testaddr 127 0 0 1
 458     expected = True
 459     actual   = addr1 <= addr2
 460
 461
 462 test_ord_instance2 :: TestTree
 463 test_ord_instance2 =
 464   testCase desc $ actual @?= expected
 465   where
 466     desc     = "127.0.0.0 is less than 127.0.1.0"
 467     addr1 = mk_testaddr 127 0 0 0
 468     addr2 = mk_testaddr 127 0 1 0
 469     expected = True
 470     actual   = addr1 <= addr2
 471
 472 test_ord_instance3 :: TestTree
 473 test_ord_instance3 =
 474   testCase desc $ actual @?= expected
 475   where
 476     desc     = "127.0.0.0 is less than 127.1.0.0"
 477     addr1 = mk_testaddr 127 0 0 0
 478     addr2 = mk_testaddr 127 1 0 0
 479     expected = True
 480     actual   = addr1 <= addr2
 481
 482 test_ord_instance4 :: TestTree
 483 test_ord_instance4 =
 484   testCase desc $ actual @?= expected
 485   where
 486     desc     = "127.0.0.0 is less than 128.0.0.0"
 487     addr1 = mk_testaddr 127 0 0 0
 488     addr2 = mk_testaddr 128 0 0 0
 489     expected = True
 490     actual   = addr1 <= addr2