X-Git-Url: https://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FCidr.hs;h=d7f624654743f24f6c3ac4a85939c56159e69e1d;hb=6087bef9274022251014f4ecbd166c35710480cd;hp=5a5ba3f2f332cdb6548aa23621859a9bc6bca6f3;hpb=6b71fc1e444cc95acdef91ad814e4f97b01ec52e;p=hath.git

diff --git a/src/Cidr.hs b/src/Cidr.hs
index 5a5ba3f..d7f6246 100644
--- a/src/Cidr.hs
+++ b/src/Cidr.hs
@@ -16,9 +16,10 @@ module Cidr
   min_octet2,
   min_octet3,
   min_octet4,
+  normalize
 ) where
 
-import Data.List (nubBy)
+import Data.List (nub)
 import Data.List.Split (splitOneOf)
 import Data.Maybe (catMaybes, mapMaybe)
 
@@ -57,14 +58,16 @@ instance Arbitrary Cidr where
 
 
 instance Eq Cidr where
-  cidr1 == cidr2 = (cidr1 `equivalent` cidr2)
+  -- | 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)
 
-
--- | 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))
+instance Ord Cidr where
+  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.
@@ -219,7 +222,7 @@ 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 ])
 
@@ -261,6 +264,14 @@ adjacent cidr1 cidr2
 enumerate :: Cidr -> [IPv4Address]
 enumerate cidr = [(min_host cidr)..(max_host cidr)]
 
+
+-- | Replace any masked bits in this CIDR's IPv4Address with zeros.
+normalize :: Cidr -> Cidr
+normalize (Cidr addr mask) =
+  Cidr nrml_addr mask
+  where
+    nrml_addr = apply_mask addr mask B.Zero
+
 -- Test lists.
 cidr_tests :: TestTree
 cidr_tests =
@@ -281,13 +292,20 @@ cidr_tests =
     test_combine_contained2,
     test_combine_all1,
     test_combine_all2,
-    test_combine_all3 ]
+    test_combine_all3,
+    test_normalize1,
+    test_normalize2,
+    test_normalize3 ]
 
 cidr_properties :: TestTree
 cidr_properties =
   testGroup "CIDR Properties" [
       prop_all_cidrs_contain_themselves,
-      prop_contains_proper_antisymmetric ]
+      prop_contains_proper_antisymmetric,
+      prop_normalize_idempotent,
+      prop_normalize_preserves_equality,
+      prop_ord_instance_reflexive,
+      prop_ord_instance_transitive ]
 
 
 -- HUnit Tests
@@ -483,6 +501,31 @@ test_combine_all3 =
     expected = [read "10.0.0.16/30" :: Cidr]
     actual = combine_all test_cidrs
 
+test_normalize1 :: TestTree
+test_normalize1 =
+  testCase desc $ actual @?= expected
+  where
+    desc = "127.0.0.1/8 normalized is 127.0.0.0/8"
+    expected = read "127.0.0.0/8" :: Cidr
+    actual = normalize (read "127.0.0.1/8" :: Cidr)
+
+
+test_normalize2 :: TestTree
+test_normalize2 =
+  testCase desc $ actual @?= expected
+  where
+    desc = "192.168.1.101/24 normalized is 192.168.1.0/24"
+    expected = read "192.168.1.0/24" :: Cidr
+    actual = normalize (read "192.168.1.101/24" :: Cidr)
+
+test_normalize3 :: TestTree
+test_normalize3 =
+  testCase desc $ actual @?= expected
+  where
+    desc = "10.10.10.10/22 normalized is 10.10.8.0/22"
+    expected = read "10.10.8.0/22" :: Cidr
+    actual = normalize (read "10.10.10.10/22" :: Cidr)
+
 -- QuickCheck Tests
 prop_all_cidrs_contain_themselves :: TestTree
 prop_all_cidrs_contain_themselves =
@@ -502,3 +545,36 @@ prop_contains_proper_antisymmetric =
     prop cidr1 cidr2 =
       (cidr1 `contains_proper` cidr2) ==>
         (not (cidr2 `contains_proper` cidr1))
+
+
+-- Running "normalize" a second time shouldn't do anything.
+prop_normalize_idempotent :: TestTree
+prop_normalize_idempotent =
+  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