src/IPv4Address.hs

   1 module IPv4Address
   2 ( ipv4address_from_octets,
   3   ipv4address_tests,
   4   IPv4Address(None),
   5   max_octet1,
   6   max_octet2,
   7   max_octet3,
   8   max_octet4,
   9   min_octet1,
  10   min_octet2,
  11   min_octet3,
  12   min_octet4,
  13   most_sig_bit_different,
  14   octet1,
  15   octet2,
  16   octet3,
  17   octet4
  18 ) where
  19
  20 import Test.HUnit
  21 import Test.QuickCheck
  22
  23 import qualified Bit as B
  24 import Maskable
  25 import Maskbits
  26 import Octet
  27
  28 data IPv4Address = None | IPv4Address { octet1 :: Octet,
  29                                         octet2 :: Octet,
  30                                         octet3 :: Octet,
  31                                         octet4 :: Octet }
  32                  deriving (Eq)
  33
  34
  35 instance Show IPv4Address where
  36     show IPv4Address.None = "None"
  37     show addr = concat [(show oct1) ++ ".",
  38                         (show oct2) ++ ".",
  39                         (show oct3) ++ ".",
  40                         (show oct4)]
  41         where
  42           oct1 = (octet1 addr)
  43           oct2 = (octet2 addr)
  44           oct3 = (octet3 addr)
  45           oct4 = (octet4 addr)
  46
  47
  48 instance Arbitrary IPv4Address where
  49     arbitrary = do
  50       oct1 <- arbitrary :: Gen Octet
  51       oct2 <- arbitrary :: Gen Octet
  52       oct3 <- arbitrary :: Gen Octet
  53       oct4 <- arbitrary :: Gen Octet
  54       return (IPv4Address oct1 oct2 oct3 oct4)
  55
  56     coarbitrary _ = variant 0
  57
  58
  59
  60 instance Maskable IPv4Address where
  61     apply_mask _ Maskbits.None = IPv4Address.None
  62     apply_mask addr mask
  63         | mask == ThirtyTwo = ipv4address_from_octets oct1 oct2 oct3 oct4
  64         | mask == ThirtyOne = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Seven)
  65         | mask == Thirty = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Six)
  66         | mask == TwentyNine = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Five)
  67         | mask == TwentyEight = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Four)
  68         | mask == TwentySeven = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Three)
  69         | mask == TwentySix = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 Two)
  70         | mask == TwentyFive = ipv4address_from_octets oct1 oct2 oct3 (apply_mask oct4 One)
  71         | mask == TwentyFour = ipv4address_from_octets oct1 oct2 oct3 (min_octet)
  72         | mask == TwentyThree = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Seven) (min_octet)
  73         | mask == TwentyTwo = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Six) (min_octet)
  74         | mask == TwentyOne = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Five) (min_octet)
  75         | mask == Twenty = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Four) (min_octet)
  76         | mask == Nineteen = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Three) (min_octet)
  77         | mask == Eighteen = ipv4address_from_octets oct1 oct2 (apply_mask oct3 Two) (min_octet)
  78         | mask == Seventeen = ipv4address_from_octets oct1 oct2 (apply_mask oct3 One) (min_octet)
  79         | mask == Sixteen = ipv4address_from_octets oct1 oct2 (min_octet) (min_octet)
  80         | mask == Fifteen = ipv4address_from_octets oct1 (apply_mask oct2 Seven) (min_octet) (min_octet)
  81         | mask == Fourteen = ipv4address_from_octets oct1 (apply_mask oct2 Six) (min_octet) (min_octet)
  82         | mask == Thirteen = ipv4address_from_octets oct1 (apply_mask oct2 Five) (min_octet) (min_octet)
  83         | mask == Twelve = ipv4address_from_octets oct1 (apply_mask oct2 Four) (min_octet) (min_octet)
  84         | mask == Eleven = ipv4address_from_octets oct1 (apply_mask oct2 Three) (min_octet) (min_octet)
  85         | mask == Ten = ipv4address_from_octets oct1 (apply_mask oct2 Two) (min_octet) (min_octet)
  86         | mask == Nine = ipv4address_from_octets oct1 (apply_mask oct2 One) (min_octet) (min_octet)
  87         | mask == Eight = ipv4address_from_octets oct1 (min_octet) (min_octet) (min_octet)
  88         | mask == Seven = ipv4address_from_octets (apply_mask oct1 Seven) (min_octet) (min_octet) (min_octet)
  89         | mask == Six = ipv4address_from_octets (apply_mask oct1 Six) (min_octet) (min_octet) (min_octet)
  90         | mask == Five = ipv4address_from_octets (apply_mask oct1 Five) (min_octet) (min_octet) (min_octet)
  91         | mask == Four =  ipv4address_from_octets (apply_mask oct1 Four) (min_octet) (min_octet) (min_octet)
  92         | mask == Three = ipv4address_from_octets (apply_mask oct1 Three) (min_octet) (min_octet) (min_octet)
  93         | mask == Two = ipv4address_from_octets (apply_mask oct1 Two) (min_octet) (min_octet) (min_octet)
  94         | mask == One = ipv4address_from_octets (apply_mask oct1 One) (min_octet) (min_octet) (min_octet)
  95         | mask == Zero = ipv4address_from_octets (min_octet) (min_octet) (min_octet) (min_octet)
  96         | otherwise = IPv4Address.None
  97         where
  98           oct1 = (octet1 addr)
  99           oct2 = (octet2 addr)
 100           oct3 = (octet3 addr)
 101           oct4 = (octet4 addr)
 102
 103
 104 -- We don't export our constructor so this function is the only
 105 -- way to construct an address from octets. As a result, we can
 106 -- return IPv4Address.None in response to being passed one of more
 107 -- Octet.None octets.
 108 ipv4address_from_octets :: Octet -> Octet -> Octet -> Octet -> IPv4Address
 109 ipv4address_from_octets oct1 oct2 oct3 oct4
 110     | or [oct1 == Octet.None,
 111           oct2 == Octet.None,
 112           oct3 == Octet.None,
 113           oct4 == Octet.None] = IPv4Address.None
 114     | otherwise = IPv4Address oct1 oct2 oct3 oct4
 115
 116
 117 min_address :: IPv4Address -> Maskbits -> IPv4Address
 118 min_address IPv4Address.None _ = IPv4Address.None
 119 min_address _ Maskbits.None = IPv4Address.None
 120 min_address addr mask
 121     | mask == ThirtyTwo = addr
 122     | mask == ThirtyOne = addr { octet4 = apply_mask oct4 Seven }
 123     | mask == Thirty = addr { octet4 = apply_mask oct4 Six }
 124     | mask == TwentyNine = addr { octet4 = apply_mask oct4 Five }
 125     | mask == TwentyEight = addr { octet4 = apply_mask oct4 Four }
 126     | mask == TwentySeven = addr { octet4 = apply_mask oct4 Three }
 127     | mask == TwentySix = addr { octet4 = apply_mask oct4 Two }
 128     | mask == TwentyFive = addr { octet4 = apply_mask oct4 One }
 129     | mask == TwentyFour = addr { octet4 = min_octet }
 130     | mask == TwentyThree = addr { octet3 = apply_mask oct3 Seven,
 131                                    octet4 = min_octet }
 132     | mask == TwentyTwo = addr { octet3 = apply_mask oct3 Six,
 133                                  octet4 = min_octet }
 134     | mask == TwentyOne = addr { octet3 = apply_mask oct3 Five,
 135                                  octet4 = min_octet }
 136     | mask == Twenty = addr { octet3 = apply_mask oct3 Four,
 137                               octet4 = min_octet }
 138     | mask == Nineteen = addr { octet3 = apply_mask oct3 Three,
 139                                 octet4 = min_octet }
 140     | mask == Eighteen = addr { octet3 = apply_mask oct3 Two,
 141                                 octet4 = min_octet }
 142     | mask == Seventeen = addr { octet3 = apply_mask oct3 One,
 143                                  octet4 = min_octet }
 144     | mask == Sixteen = addr { octet3 = min_octet,
 145                                octet4 = min_octet }
 146     | mask == Fifteen = addr { octet2 = apply_mask oct2 Seven,
 147                                octet3 = min_octet,
 148                                octet4 = min_octet }
 149     | mask == Fourteen = addr { octet2 = apply_mask oct2 Six,
 150                                 octet3 = min_octet,
 151                                 octet4 = min_octet }
 152     | mask == Thirteen = addr { octet2 = apply_mask oct2 Five,
 153                                 octet3 = min_octet,
 154                                 octet4 = min_octet }
 155     | mask == Twelve = addr { octet2 = apply_mask oct2 Four,
 156                               octet3 = min_octet,
 157                               octet4 = min_octet }
 158     | mask == Eleven = addr { octet2 = apply_mask oct2 Three,
 159                               octet3 = min_octet,
 160                               octet4 = min_octet }
 161     | mask == Ten = addr { octet2 = apply_mask oct2 Two,
 162                            octet3 = min_octet,
 163                            octet4 = min_octet }
 164     | mask == Nine = addr { octet2 = apply_mask oct2 One,
 165                             octet3 = min_octet,
 166                             octet4 = min_octet }
 167     | mask == Eight = addr { octet2 = min_octet,
 168                              octet3 = min_octet,
 169                              octet4 = min_octet }
 170     | mask == Seven = addr { octet1 = apply_mask oct1 Seven,
 171                              octet2 = min_octet,
 172                              octet3 = min_octet,
 173                              octet4 = min_octet }
 174     | mask == Six = addr { octet1 = apply_mask oct1 Six,
 175                            octet2 = min_octet,
 176                            octet3 = min_octet,
 177                            octet4 = min_octet }
 178     | mask == Five = addr { octet1 = apply_mask oct1 Five,
 179                             octet2 = min_octet,
 180                             octet3 = min_octet,
 181                             octet4 = min_octet }
 182     | mask == Four = addr { octet1 = apply_mask oct1 Four,
 183                             octet2 = min_octet,
 184                             octet3 = min_octet,
 185                             octet4 = min_octet }
 186     | mask == Three = addr { octet1 = apply_mask oct1 Three,
 187                              octet2 = min_octet,
 188                              octet3 = min_octet,
 189                              octet4 = min_octet }
 190     | mask == Two = addr { octet1 = apply_mask oct1 Two,
 191                            octet2 = min_octet,
 192                            octet3 = min_octet,
 193                            octet4 = min_octet }
 194     | mask == One = addr { octet1 = apply_mask oct1 One,
 195                            octet2 = min_octet,
 196                            octet3 = min_octet,
 197                            octet4 = min_octet }
 198     | mask == Zero = addr { octet1 = min_octet,
 199                             octet2 = min_octet,
 200                             octet3 = min_octet,
 201                             octet4 = min_octet }
 202     | otherwise = addr
 203     where
 204       oct1 = (octet1 addr)
 205       oct2 = (octet2 addr)
 206       oct3 = (octet3 addr)
 207       oct4 = (octet4 addr)
 208
 209
 210
 211 max_address :: IPv4Address -> Maskbits -> IPv4Address
 212 max_address IPv4Address.None _ = IPv4Address.None
 213 max_address _ Maskbits.None = IPv4Address.None
 214 max_address addr mask
 215     | mask == ThirtyTwo = IPv4Address oct1 oct2 oct3 oct4
 216     | mask == ThirtyOne = IPv4Address oct1 oct2 oct3 (Octet a25 a26 a27 a28 a29 a30 a31 B.One)
 217     | mask == Thirty = IPv4Address oct1 oct2 oct3 (Octet a25 a26 a27 a28 a29 a30 B.One B.One)
 218     | mask == TwentyNine = IPv4Address oct1 oct2 oct3 (Octet a25 a26 a27 a28 a29 B.One B.One B.One)
 219     | mask == TwentyEight = IPv4Address oct1 oct2 oct3 (Octet a25 a26 a27 a28 B.One B.One B.One B.One)
 220     | mask == TwentySeven = IPv4Address oct1 oct2 oct3 (Octet a25 a26 a27 B.One B.One B.One B.One B.One)
 221     | mask == TwentySix = IPv4Address oct1 oct2 oct3 (Octet a25 a26 B.One B.One B.One B.One B.One B.One)
 222     | mask == TwentyFive = IPv4Address oct1 oct2 oct3 (Octet a25 B.One B.One B.One B.One B.One B.One B.One)
 223     | mask == TwentyFour = IPv4Address oct1 oct2 oct3 (max_octet)
 224     | mask == TwentyThree = IPv4Address oct1 oct2 (Octet a17 a18 a19 a20 a21 a22 a23 B.One) (max_octet)
 225     | mask == TwentyTwo = IPv4Address oct1 oct2 (Octet a17 a18 a19 a20 a21 a22 B.One B.One) (max_octet)
 226     | mask == TwentyOne = IPv4Address oct1 oct2 (Octet a17 a18 a19 a20 a21 B.One B.One B.One) (max_octet)
 227     | mask == Twenty = IPv4Address oct1 oct2 (Octet a17 a18 a19 a20 B.One B.One B.One B.One) (max_octet)
 228     | mask == Nineteen = IPv4Address oct1 oct2 (Octet a17 a18 a19 B.One B.One B.One B.One B.One) (max_octet)
 229     | mask == Eighteen = IPv4Address oct1 oct2 (Octet a17 a18 B.One B.One B.One B.One B.One B.One) (max_octet)
 230     | mask == Seventeen = IPv4Address oct1 oct2 (Octet a17 B.One B.One B.One B.One B.One B.One B.One) (max_octet)
 231     | mask == Sixteen = IPv4Address oct1 oct2 (max_octet) (max_octet)
 232     | mask == Fifteen = IPv4Address oct1 (Octet a9 a10 a11 a12 a13 a14 a15 B.One) (max_octet) (max_octet)
 233     | mask == Fourteen = IPv4Address oct1 (Octet a9 a10 a11 a12 a13 a14 B.One B.One) (max_octet) (max_octet)
 234     | mask == Thirteen = IPv4Address oct1 (Octet a9 a10 a11 a12 a13 B.One B.One B.One) (max_octet) (max_octet)
 235     | mask == Twelve = IPv4Address oct1 (Octet a9 a10 a11 a12 B.One B.One B.One B.One) (max_octet) (max_octet)
 236     | mask == Eleven = IPv4Address oct1 (Octet a9 a10 a11 B.One B.One B.One B.One B.One) (max_octet) (max_octet)
 237     | mask == Ten = IPv4Address oct1 (Octet a9 a10 B.One B.One B.One B.One B.One B.One) (max_octet) (max_octet)
 238     | mask == Nine = IPv4Address oct1 (Octet a9 B.One B.One B.One B.One B.One B.One B.One) (max_octet) (max_octet)
 239     | mask == Eight = IPv4Address oct1 (max_octet) (max_octet) (max_octet)
 240     | mask == Seven = IPv4Address (Octet a1 a2 a3 a4 a5 a6 a7 B.One) (max_octet) (max_octet) (max_octet)
 241     | mask == Six = IPv4Address (Octet a1 a2 a3 a4 a5 a6 B.One B.One) (max_octet) (max_octet) (max_octet)
 242     | mask == Five = IPv4Address (Octet a1 a2 a3 a4 a5 B.One B.One B.One) (max_octet) (max_octet) (max_octet)
 243     | mask == Four = IPv4Address (Octet a1 a2 a3 a4 B.One B.One B.One B.One) (max_octet) (max_octet) (max_octet)
 244     | mask == Three = IPv4Address (Octet a1 a2 a3 B.One B.One B.One B.One B.One) (max_octet) (max_octet) (max_octet)
 245     | mask == Two = IPv4Address (Octet a1 a2 B.One B.One B.One B.One B.One B.One) (max_octet) (max_octet) (max_octet)
 246     | mask == One = IPv4Address (Octet a1 B.One B.One B.One B.One B.One B.One B.One) (max_octet) (max_octet) (max_octet)
 247     | mask == Zero = IPv4Address (max_octet) (max_octet) (max_octet) (max_octet)
 248     | otherwise = addr
 249     where
 250       a1  = (b1 oct1)
 251       a2  = (b2 oct1)
 252       a3  = (b3 oct1)
 253       a4  = (b4 oct1)
 254       a5  = (b5 oct1)
 255       a6  = (b6 oct1)
 256       a7  = (b7 oct1)
 257       a9  = (b1 oct2)
 258       a10 = (b2 oct2)
 259       a11 = (b3 oct2)
 260       a12 = (b4 oct2)
 261       a13 = (b5 oct2)
 262       a14 = (b6 oct2)
 263       a15 = (b7 oct2)
 264       a17 = (b1 oct3)
 265       a18 = (b2 oct3)
 266       a19 = (b3 oct3)
 267       a20 = (b4 oct3)
 268       a21 = (b5 oct3)
 269       a22 = (b6 oct3)
 270       a23 = (b7 oct3)
 271       a25 = (b1 oct4)
 272       a26 = (b2 oct4)
 273       a27 = (b3 oct4)
 274       a28 = (b4 oct4)
 275       a29 = (b5 oct4)
 276       a30 = (b6 oct4)
 277       a31 = (b7 oct4)
 278       oct1 = (octet1 addr)
 279       oct2 = (octet2 addr)
 280       oct3 = (octet3 addr)
 281       oct4 = (octet4 addr)
 282
 283
 284
 285 min_octet1 :: IPv4Address -> Maskbits -> Octet
 286 min_octet1 addr mask = octet1 (min_address addr mask)
 287
 288 min_octet2 :: IPv4Address -> Maskbits -> Octet
 289 min_octet2 addr mask = octet2 (min_address addr mask)
 290
 291 min_octet3 :: IPv4Address -> Maskbits -> Octet
 292 min_octet3 addr mask = octet3 (min_address addr mask)
 293
 294 min_octet4 :: IPv4Address -> Maskbits -> Octet
 295 min_octet4 addr mask = octet4 (min_address addr mask)
 296
 297 max_octet1 :: IPv4Address -> Maskbits -> Octet
 298 max_octet1 addr mask = octet1 (max_address addr mask)
 299
 300 max_octet2 :: IPv4Address -> Maskbits -> Octet
 301 max_octet2 addr mask = octet2 (max_address addr mask)
 302
 303 max_octet3 :: IPv4Address -> Maskbits -> Octet
 304 max_octet3 addr mask = octet3 (max_address addr mask)
 305
 306 max_octet4 :: IPv4Address -> Maskbits -> Octet
 307 max_octet4 addr mask = octet4 (max_address addr mask)
 308
 309
 310 -- Given two addresses, find the number of the most significant bit
 311 -- where they differ. If the addresses are the same, return
 312 -- Maskbits.Zero.
 313 most_sig_bit_different :: IPv4Address -> IPv4Address -> Maskbits
 314 most_sig_bit_different addr1 addr2
 315   | addr1 == addr2 = Maskbits.Zero
 316   | m1  /= n1  = Maskbits.One
 317   | m2  /= n2  = Two
 318   | m3  /= n3  = Three
 319   | m4  /= n4  = Four
 320   | m5  /= n5  = Five
 321   | m6  /= n6  = Six
 322   | m7  /= n7  = Seven
 323   | m8  /= n8  = Eight
 324   | m9  /= n9  = Nine
 325   | m10 /= n10 = Ten
 326   | m11 /= n11 = Eleven
 327   | m12 /= n12 = Twelve
 328   | m13 /= n13 = Thirteen
 329   | m14 /= n14 = Fourteen
 330   | m15 /= n15 = Fifteen
 331   | m16 /= n16 = Sixteen
 332   | m17 /= n17 = Seventeen
 333   | m18 /= n18 = Eighteen
 334   | m19 /= n19 = Nineteen
 335   | m20 /= n20 = Twenty
 336   | m21 /= n21 = TwentyOne
 337   | m22 /= n22 = TwentyTwo
 338   | m23 /= n23 = TwentyThree
 339   | m24 /= n24 = TwentyFour
 340   | m25 /= n25 = TwentyFive
 341   | m26 /= n26 = TwentySix
 342   | m27 /= n27 = TwentySeven
 343   | m28 /= n28 = TwentyEight
 344   | m29 /= n29 = TwentyNine
 345   | m30 /= n30 = Thirty
 346   | m31 /= n31 = ThirtyOne
 347   | m32 /= n32 = ThirtyTwo
 348   | otherwise  = Maskbits.Zero
 349   where
 350     m1  = (b1 oct1a)
 351     m2  = (b2 oct1a)
 352     m3  = (b3 oct1a)
 353     m4  = (b4 oct1a)
 354     m5  = (b5 oct1a)
 355     m6  = (b6 oct1a)
 356     m7  = (b7 oct1a)
 357     m8  = (b8 oct1a)
 358     m9  = (b1 oct2a)
 359     m10 = (b2 oct2a)
 360     m11 = (b3 oct2a)
 361     m12 = (b4 oct2a)
 362     m13 = (b5 oct2a)
 363     m14 = (b6 oct2a)
 364     m15 = (b7 oct2a)
 365     m16 = (b8 oct2a)
 366     m17 = (b1 oct3a)
 367     m18 = (b2 oct3a)
 368     m19 = (b3 oct3a)
 369     m20 = (b4 oct3a)
 370     m21 = (b5 oct3a)
 371     m22 = (b6 oct3a)
 372     m23 = (b7 oct3a)
 373     m24 = (b8 oct3a)
 374     m25 = (b1 oct4a)
 375     m26 = (b2 oct4a)
 376     m27 = (b3 oct4a)
 377     m28 = (b4 oct4a)
 378     m29 = (b5 oct4a)
 379     m30 = (b6 oct4a)
 380     m31 = (b7 oct4a)
 381     m32 = (b8 oct4a)
 382     oct1a = (octet1 addr1)
 383     oct2a = (octet2 addr1)
 384     oct3a = (octet3 addr1)
 385     oct4a = (octet4 addr1)
 386     n1  = (b1 oct1b)
 387     n2  = (b2 oct1b)
 388     n3  = (b3 oct1b)
 389     n4  = (b4 oct1b)
 390     n5  = (b5 oct1b)
 391     n6  = (b6 oct1b)
 392     n7  = (b7 oct1b)
 393     n8  = (b8 oct1b)
 394     n9  = (b1 oct2b)
 395     n10 = (b2 oct2b)
 396     n11 = (b3 oct2b)
 397     n12 = (b4 oct2b)
 398     n13 = (b5 oct2b)
 399     n14 = (b6 oct2b)
 400     n15 = (b7 oct2b)
 401     n16 = (b8 oct2b)
 402     n17 = (b1 oct3b)
 403     n18 = (b2 oct3b)
 404     n19 = (b3 oct3b)
 405     n20 = (b4 oct3b)
 406     n21 = (b5 oct3b)
 407     n22 = (b6 oct3b)
 408     n23 = (b7 oct3b)
 409     n24 = (b8 oct3b)
 410     n25 = (b1 oct4b)
 411     n26 = (b2 oct4b)
 412     n27 = (b3 oct4b)
 413     n28 = (b4 oct4b)
 414     n29 = (b5 oct4b)
 415     n30 = (b6 oct4b)
 416     n31 = (b7 oct4b)
 417     n32 = (b8 oct4b)
 418     oct1b = (octet1 addr2)
 419     oct2b = (octet2 addr2)
 420     oct3b = (octet3 addr2)
 421     oct4b = (octet4 addr2)
 422
 423
 424
 425 -- HUnit Tests
 426 mk_testaddr :: Int -> Int -> Int -> Int -> IPv4Address
 427 mk_testaddr a b c d =
 428     IPv4Address oct1 oct2 oct3 oct4
 429     where
 430       oct1 = octet_from_int a
 431       oct2 = octet_from_int b
 432       oct3 = octet_from_int c
 433       oct4 = octet_from_int d
 434
 435
 436 test_most_sig_bit_different1 :: Test
 437 test_most_sig_bit_different1 =
 438     TestCase $ assertEqual "10.1.1.0 and 10.1.0.0 differ in bit 24" TwentyFour (most_sig_bit_different (mk_testaddr 10 1 1 0) (mk_testaddr 10 1 0 0))
 439
 440
 441 test_most_sig_bit_different2 :: Test
 442 test_most_sig_bit_different2 =
 443     TestCase $ assertEqual "10.1.2.0 and 10.1.1.0 differ in bit 23" TwentyThree (most_sig_bit_different (mk_testaddr 10 1 2 0) (mk_testaddr 10 1 1 0))
 444
 445
 446 ipv4address_tests :: [Test]
 447 ipv4address_tests = [ test_most_sig_bit_different1,
 448                       test_most_sig_bit_different2 ]