X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FIPv4Address.hs;h=38aec8dd39c5250279a05357db753c8aa2247cf2;hb=HEAD;hp=dac7ddaf0596e9fba46b077d4321e88149d23b88;hpb=d32fe2f0a6c83ba3046a405eda40f83c794c000d;p=hath.git diff --git a/src/IPv4Address.hs b/src/IPv4Address.hs index dac7dda..f9fd8c2 100644 --- a/src/IPv4Address.hs +++ b/src/IPv4Address.hs @@ -1,27 +1,40 @@ -module IPv4Address -( ipv4address_tests, +module IPv4Address( IPv4Address(..), - max_address, - min_address, - most_sig_bit_different, -) where - -import Data.Maybe (fromJust) -import Test.HUnit (assertEqual) -import Test.Framework (Test, testGroup) -import Test.Framework.Providers.HUnit (testCase) -import Test.QuickCheck (Arbitrary(..), Gen) - -import Maskable -import Maskbits -import Octet + ipv4address_properties, + ipv4address_tests, + most_sig_bit_different ) +where + +import Data.Int ( Int32, Int64 ) +import Data.Word ( Word32 ) + +import Test.Tasty ( TestTree, testGroup ) +import Test.Tasty.HUnit ( (@?=), testCase ) +import Test.Tasty.QuickCheck ( + Arbitrary( arbitrary ), + Gen, + Large, + Property, + Small, + (==>), + testProperty ) + +import Maskable ( Maskable( apply_mask) ) +import Maskbits ( + Maskbits( + Zero, One, Two, Three, Four, Five, Six, Seven, Eight, + Nine, Ten, Eleven, Twelve, Thirteen, Fourteen, Fifteen, Sixteen, + Seventeen, Eighteen, Nineteen, Twenty, TwentyOne, TwentyTwo, TwentyThree, + TwentyFour, TwentyFive, TwentySix, TwentySeven, TwentyEight, TwentyNine, + Thirty, ThirtyOne, ThirtyTwo ) ) +import Octet ( Octet( b1, b2, b3, b4, b5, b6, b7, b8) ) data IPv4Address = IPv4Address { octet1 :: Octet, octet2 :: Octet, octet3 :: Octet, octet4 :: Octet } - deriving (Eq) + deriving (Eq, Ord) instance Show IPv4Address where @@ -165,18 +178,57 @@ instance Maskable IPv4Address where new_addr3 { octet1 = (apply_mask oct1 Zero bit) } - --- | The minimum possible IPv4 address, 0.0.0.0. -min_address :: IPv4Address -min_address = - IPv4Address min_octet min_octet min_octet min_octet - - --- | The maximum possible IPv4 address, 255.255.255.255. -max_address :: IPv4Address -max_address = - IPv4Address max_octet max_octet max_octet max_octet - +instance Bounded IPv4Address where + -- | The minimum possible IPv4 address, 0.0.0.0. + minBound = IPv4Address minBound minBound minBound minBound + + -- | The maximum possible IPv4 address, 255.255.255.255. + maxBound = IPv4Address maxBound maxBound maxBound maxBound + + + + +instance Enum IPv4Address where + -- | Convert an 'Int' @x@ to an 'IPv4Address'. Each octet of @x@ is + -- right-shifted by the appropriate number of bits, and the fractional + -- part is dropped. + toEnum signed_x = + IPv4Address oct1 oct2 oct3 oct4 + where + -- Convert the input Int to a Word32 before we proceed. On x86, + -- the Int that we get could be negative (half of all IP + -- addresses correspond to negative numbers), and then the magic + -- below doesn't work. The Word32 type is unsigned, so we do the + -- math on that and then convert everything back to Int later on + -- once we have four much-smaller non-negative numbers. + x = fromIntegral signed_x :: Word32 + + -- Chop off the higher octets. x1 = x `mod` 2^32, would be + -- redundant. + x2 = x `mod` (2 ^ (24 :: Integer)) + x3 = x `mod` (2 ^ (16 :: Integer)) + x4 = (fromIntegral $ x `mod` (2 ^ (8 :: Integer))) :: Int + -- Perform right-shifts. x4 doesn't need a shift. + shifted_x1 = (fromIntegral $ x `quot` (2 ^ (24 :: Integer))) :: Int + shifted_x2 = (fromIntegral $ x2 `quot` (2 ^ (16 :: Integer))) :: Int + shifted_x3 = (fromIntegral $ x3 `quot` (2 ^ (8 :: Integer))) :: Int + oct1 = toEnum shifted_x1 :: Octet + oct2 = toEnum shifted_x2 :: Octet + oct3 = toEnum shifted_x3 :: Octet + oct4 = toEnum x4 :: Octet + + -- | Convert @addr@ to an 'Int' by converting each octet to an 'Int' + -- and shifting the result to the left by 0,8.16, or 24 bits. + fromEnum addr = + (shifted_oct1) + (shifted_oct2) + (shifted_oct3) + oct4 + where + oct1 = fromEnum (octet1 addr) + oct2 = fromEnum (octet2 addr) + oct3 = fromEnum (octet3 addr) + oct4 = fromEnum (octet4 addr) + shifted_oct1 = oct1 * (2 ^ (24 :: Integer)) + shifted_oct2 = oct2 * (2 ^ (16 :: Integer)) + shifted_oct3 = oct3 * (2 ^ (8 :: Integer)) -- | Given two addresses, find the number of the most significant bit -- where they differ. If the addresses are the same, return @@ -292,45 +344,175 @@ most_sig_bit_different addr1 addr2 oct4b = (octet4 addr2) +-- Test lists. +ipv4address_tests :: TestTree +ipv4address_tests = + testGroup "IPv4 Address Tests" [ + test_enum, + test_maxBound, + test_minBound, + test_most_sig_bit_different1, + test_most_sig_bit_different2, + test_ord_instance1, + test_ord_instance2, + test_ord_instance3, + test_ord_instance4, + test_to_enum ] + +ipv4address_properties :: TestTree +ipv4address_properties = + testGroup + "IPv4 Address Properties " + [ prop_from_enum_to_enum_inverses_x32, + prop_from_enum_to_enum_inverses_x64 ] + +-- QuickCheck properties +-- +-- We have two different tests to show that toEnum and fromEnum are +-- inverses of one another. This part of the code isn't really +-- type-safe, because the stupid Enum class insists that we use a +-- machine 'Int' for our representation. Since IPv4 addresses can +-- correspond to very large 32-bit integers, there's a possibility +-- that our math is wrong in 32- but not 64-bits, and vice-versa. +-- +-- tl;dr we want to ensure that this test passes when the 'Int' type +-- is both 32-bit and 64-bit. + +-- Generate "Small" 64-bit numbers, because almost all 64-bit integers are +-- too large to satisfy our predicate (i.e. also be 32-bit integers). +prop_from_enum_to_enum_inverses_x64 :: TestTree +prop_from_enum_to_enum_inverses_x64 = + testProperty "fromEnum and toEnum are inverses (x64)" prop + where + prop :: (Small Int64) -> Property + prop x = + 0 <= x && x <= (2 ^ (32 :: Integer)) - 1 ==> + fromIntegral (fromEnum (toEnum (fromIntegral x) :: IPv4Address)) == x + +-- According to the QuickCheck documentation, we need the "Large" +-- modifier to ensure that the test cases are drawn from the entire +-- range of Int32 values. +prop_from_enum_to_enum_inverses_x32 :: TestTree +prop_from_enum_to_enum_inverses_x32 = + testProperty "fromEnum and toEnum are inverses (x32)" prop + where + prop :: (Large Int32) -> Bool + prop x = + fromIntegral (fromEnum (toEnum (fromIntegral x) :: IPv4Address)) == x -- HUnit Tests mk_testaddr :: Int -> Int -> Int -> Int -> IPv4Address mk_testaddr a b c d = IPv4Address oct1 oct2 oct3 oct4 where - oct1 = fromJust $ octet_from_int a - oct2 = fromJust $ octet_from_int b - oct3 = fromJust $ octet_from_int c - oct4 = fromJust $ octet_from_int d + oct1 = toEnum a :: Octet + oct2 = toEnum b :: Octet + oct3 = toEnum c :: Octet + oct4 = toEnum d :: Octet + + +test_minBound :: TestTree +test_minBound = + testCase desc $ actual @?= expected + where + desc = "minBound should be 0.0.0.0" + expected = mk_testaddr 0 0 0 0 + actual = minBound :: IPv4Address + + +test_maxBound :: TestTree +test_maxBound = + testCase desc $ actual @?= expected + where + desc = "maxBound should be 255.255.255.255" + expected = mk_testaddr 255 255 255 255 + actual = maxBound :: IPv4Address + + +test_enum :: TestTree +test_enum = + testCase desc $ actual @?= expected + where + desc = "enumerating a /24 gives the correct addresses" + expected = ["192.168.0." ++ (show x) | x <- [0..255::Int] ] + lb = mk_testaddr 192 168 0 0 + ub = mk_testaddr 192 168 0 255 + actual = map show [lb..ub] -test_most_sig_bit_different1 :: Test +test_most_sig_bit_different1 :: TestTree test_most_sig_bit_different1 = - testCase desc $ assertEqual desc - TwentyFour - bit + testCase desc $ actual @?= expected where desc = "10.1.1.0 and 10.1.0.0 differ in bit 24" addr1 = mk_testaddr 10 1 1 0 addr2 = (mk_testaddr 10 1 0 0) - bit = most_sig_bit_different addr1 addr2 + expected = TwentyFour + actual = most_sig_bit_different addr1 addr2 -test_most_sig_bit_different2 :: Test +test_most_sig_bit_different2 :: TestTree test_most_sig_bit_different2 = - testCase desc $ assertEqual desc - TwentyThree - bit + testCase desc $ actual @?= expected where desc = "10.1.2.0 and 10.1.1.0 differ in bit 23" addr1 = mk_testaddr 10 1 2 0 addr2 = mk_testaddr 10 1 1 0 - bit = most_sig_bit_different addr1 addr2 + expected = TwentyThree + actual = most_sig_bit_different addr1 addr2 -ipv4address_tests :: Test -ipv4address_tests = - testGroup "IPv4 Address Tests" [ - test_most_sig_bit_different1, - test_most_sig_bit_different2 ] +test_to_enum :: TestTree +test_to_enum = + testCase desc $ actual @?= expected + where + desc = "192.168.0.0 in base-10 is 3232235520" + expected = mk_testaddr 192 168 0 0 + -- We declare the big number as Word32 because otherwise, on x86, + -- we get a warning that it's too big to fit in a 32-bit integer. + -- Ultimately we convert it to a (negative) Int on those systems + -- anyway, but the gymnastics declare our intent to the compiler. + actual = toEnum (fromIntegral (3232235520 :: Word32)) :: IPv4Address + + +test_ord_instance1 :: TestTree +test_ord_instance1 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 127.0.0.1" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 127 0 0 1 + expected = True + actual = addr1 <= addr2 + + +test_ord_instance2 :: TestTree +test_ord_instance2 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 127.0.1.0" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 127 0 1 0 + expected = True + actual = addr1 <= addr2 + +test_ord_instance3 :: TestTree +test_ord_instance3 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 127.1.0.0" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 127 1 0 0 + expected = True + actual = addr1 <= addr2 + +test_ord_instance4 :: TestTree +test_ord_instance4 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 128.0.0.0" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 128 0 0 0 + expected = True + actual = addr1 <= addr2