X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FCidr.hs;h=9ed146ab92a08c1c889a610b23e69e5314a3efa8;hb=08f26e2f4458e2b9cbc30eab9f5fdd0b0b44b248;hp=8991c7f29d19a4b1b2bb673cb901fbc6cfaa4b4e;hpb=278b96d51a495b912243efa3a83407d3f830d83f;p=hath.git diff --git a/src/Cidr.hs b/src/Cidr.hs index 8991c7f..9ed146a 100644 --- a/src/Cidr.hs +++ b/src/Cidr.hs @@ -19,16 +19,17 @@ module Cidr normalize ) where -import Data.List (nubBy) +import Data.List (nub) import Data.List.Split (splitOneOf) import Data.Maybe (catMaybes, mapMaybe) -import Test.Tasty ( TestTree, testGroup ) +import Test.Tasty ( TestTree, localOption, testGroup ) import Test.Tasty.HUnit ( (@?=), testCase ) import Test.Tasty.QuickCheck ( Arbitrary( arbitrary ), Gen, Property, + QuickCheckTests( QuickCheckTests ), (==>), testProperty ) import Text.Read (readMaybe) @@ -58,14 +59,29 @@ instance Arbitrary Cidr where instance Eq Cidr where - cidr1 == cidr2 = (cidr1 `equivalent` cidr2) - - --- | Two CIDR ranges are equivalent if they have the same network bits --- and the masks are the same. -equivalent :: Cidr -> Cidr -> Bool -equivalent (Cidr addr1 mbits1) (Cidr addr2 mbits2) = - (mbits1 == mbits2) && ((apply_mask addr1 mbits1 B.Zero) == (apply_mask addr2 mbits2 B.Zero)) + -- | Two CIDRs are equal if they have the same network bits and if + -- their masks are the same. In other words, if they are the same + -- after normalization. + cidr1 == cidr2 = (cidr1 <= cidr2) && (cidr2 <= cidr1) + +instance Ord Cidr where + -- | The CIDR order is simply numeric, with the IPv4Address being + -- considered first, before the mask. There was an arbitrary + -- choice that had to be made here: which CIDR is smaller, + -- 127.0.0.1/8, or 127.0.0.1/32? + -- + -- The arguments for 127.0.0.1/8 <= 127.0.0.1/32 are that it + -- agrees with the numeric sort order on masks, and that it's + -- generally nicer to see the big networks before the small ones. + -- + -- On the other hand, this order disagrees with the containment + -- partial order, since 127.0.0.1/32 is contained properly in + -- 127.0.0.1/8. + -- + cidr1 <= cidr2 = if addr1 == addr2 then mask1 <= mask2 else addr1 <= addr2 + where + Cidr addr1 mask1 = normalize cidr1 + Cidr addr2 mask2 = normalize cidr2 -- | Returns the mask portion of a CIDR address. That is, everything -- after the trailing slash. @@ -220,7 +236,7 @@ combine_all cidrs | cidrs == (combine_contained unique_cidrs) = cidrs | otherwise = combine_all (combine_contained unique_cidrs) where - unique_cidrs = nubBy equivalent cidr_combinations + unique_cidrs = nub cidr_combinations cidr_combinations = cidrs ++ (catMaybes [ (combine_adjacent x y) | x <- cidrs, y <- cidrs ]) @@ -293,14 +309,24 @@ cidr_tests = test_combine_all3, test_normalize1, test_normalize2, - test_normalize3 ] + test_normalize3, + test_big_networks_come_first ] cidr_properties :: TestTree cidr_properties = testGroup "CIDR Properties" [ prop_all_cidrs_contain_themselves, prop_contains_proper_antisymmetric, - prop_normalize_idempotent ] + prop_normalize_idempotent, + prop_normalize_preserves_equality, + prop_ord_instance_antisymmetric, + prop_ord_instance_reflexive, + prop_ord_instance_transitive, + prop_ord_uses_addr_when_masks_equal, + prop_ord_uses_mask_when_addrs_equal, + prop_ord_and_contains_disagree, + prop_ord_minimum, + prop_ord_maximum ] -- HUnit Tests @@ -521,6 +547,18 @@ test_normalize3 = expected = read "10.10.8.0/22" :: Cidr actual = normalize (read "10.10.10.10/22" :: Cidr) +-- | Test a stated property of the Ord instance, namely that the big +-- network 127.0.0.1/8 comes before the small network 127.0.0.1/32. +test_big_networks_come_first :: TestTree +test_big_networks_come_first = + testCase desc $ actual @?= expected + where + desc = "127.0.0.1/8 comes before 127.0.0.1/32" + big = read "127.0.0.1/8" :: Cidr + small = read "127.0.0.1/32" :: Cidr + expected = True + actual = big <= small -- not a typo + -- QuickCheck Tests prop_all_cidrs_contain_themselves :: TestTree prop_all_cidrs_contain_themselves = @@ -545,7 +583,104 @@ prop_contains_proper_antisymmetric = -- Running "normalize" a second time shouldn't do anything. prop_normalize_idempotent :: TestTree prop_normalize_idempotent = - testProperty "The CIDR \"normalize\" function is idempotent " prop + testProperty "The CIDR \"normalize\" function is idempotent" prop where prop :: Cidr -> Bool prop cidr = (normalize cidr) == (normalize (normalize cidr)) + +-- Normalization should not affect equality of two CIDRs. +prop_normalize_preserves_equality :: TestTree +prop_normalize_preserves_equality = + testProperty "The CIDR \"normalize\" function preserves equality" prop + where + prop :: Cidr -> Cidr -> Bool + prop cidr1 cidr2 = (cidr1 == cidr2) == (normalize cidr1 == normalize cidr2) + + +prop_ord_instance_reflexive :: TestTree +prop_ord_instance_reflexive = + testProperty "The CIDR order is reflexive" prop + where + prop :: Cidr -> Bool + prop cidr = cidr <= cidr + + +prop_ord_instance_transitive :: TestTree +prop_ord_instance_transitive = + testProperty "The CIDR order is transitive" prop + where + prop :: Cidr -> Cidr -> Cidr -> Property + prop cidr1 cidr2 cidr3 = + (cidr1 <= cidr2 && cidr2 <= cidr3) ==> cidr1 <= cidr3 + +-- This is how Eq is currently implemented, but it is useful to have +-- around in case that changes. Try fewer instances of this than usual +-- because it's a rare condition. +prop_ord_instance_antisymmetric :: TestTree +prop_ord_instance_antisymmetric = + localOption (QuickCheckTests 500) $ + testProperty "The CIDR order is antisymmetric" prop + where + prop :: Cidr -> Cidr -> Property + prop cidr1 cidr2 = + (cidr1 <= cidr2 && cidr2 <= cidr1) ==> cidr1 == cidr2 + + +-- When comparing two CIDRs with the same mask, the comparison +-- should be numeric (i.e. whatever the IPv4Address does). +-- Of course, we have to normalize first. +prop_ord_uses_addr_when_masks_equal :: TestTree +prop_ord_uses_addr_when_masks_equal = + testProperty "The CIDR order is the IPv4Address order for equal masks" prop + where + prop :: Cidr -> Cidr -> Property + prop cidr1 cidr2 = + (mask1 == mask2) ==> (cidr1 <= cidr2) == (addr1 <= addr2) + where + (Cidr addr1 mask1) = normalize cidr1 + (Cidr addr2 mask2) = normalize cidr2 + + +-- If we have two CIDRs whose normalized addresses agree, then we want +-- to use the mask order, i.e. that big networks come before small +-- networks. This disagrees with containment order. +prop_ord_uses_mask_when_addrs_equal :: TestTree +prop_ord_uses_mask_when_addrs_equal = + localOption (QuickCheckTests 500) $ + testProperty "The CIDR order is by mask when the addresses agree" prop + where + prop :: Cidr -> Cidr -> Property + prop cidr1 cidr2 = + (addr1 == addr2) ==> (cidr1 <= cidr2) == (mask1 <= mask2) + where + (Cidr addr1 mask1) = normalize cidr1 + (Cidr addr2 mask2) = normalize cidr2 + + +-- Big networks come first. +prop_ord_and_contains_disagree :: TestTree +prop_ord_and_contains_disagree = + testProperty "The CIDR order disagrees with containment" prop + where + prop :: Cidr -> Cidr -> Property + prop cidr1 cidr2 = (cidr1 `contains` cidr2) ==> (cidr1 <= cidr2) + + +-- The biggest network always comes first. +prop_ord_minimum :: TestTree +prop_ord_minimum = + testProperty "The CIDR order has 0.0.0.0/0 as a minimum" prop + where + min_cidr = read "0.0.0.0/0" :: Cidr + prop :: Cidr -> Bool + prop cidr = min_cidr <= cidr + + +-- The CIDR order also has a maximum. +prop_ord_maximum :: TestTree +prop_ord_maximum = + testProperty "The CIDR order has 255.255.255.255/32 as a maximum" prop + where + max_cidr = read "255.255.255.255/32" :: Cidr + prop :: Cidr -> Bool + prop cidr = max_cidr >= cidr