module Cidr
-( Cidr,
- from_string,
- is_valid_cidr,
- min_first_octet,
- max_first_octet,
- min_second_octet,
- max_second_octet,
- min_third_octet,
- max_third_octet,
- min_fourth_octet,
- max_fourth_octet
+( Cidr(..),
+ cidr_from_string,
+ cidr_tests,
+ combine_all,
+ contains,
+ contains_proper,
+ max_octet1,
+ max_octet2,
+ max_octet3,
+ max_octet4,
+ min_octet1,
+ min_octet2,
+ min_octet3,
+ min_octet4,
+ prop_all_cidrs_contain_themselves,
+ prop_contains_proper_intransitive
) where
-import Data.Char (digitToInt, intToDigit)
-import Numeric (readInt, showIntAtBase)
-import Text.Regex.Posix
+import Data.List (nubBy)
+import Test.HUnit
+import Test.QuickCheck
+import qualified Bit as B
+import IPv4Address
import ListUtils
+import Maskable
+import Maskbits
+import Octet
-type Maskbits = Int
-type Octet = Int
-type OctetList = (Octet, Octet, Octet, Octet)
-type BaseTwoOctetList = (String, String, String, String)
-data Cidr = Cidr { octet1 :: Octet,
- octet2 :: Octet,
- octet3 :: Octet,
- octet4 :: Octet,
- maskbits :: Maskbits }
- deriving (Show)
+data Cidr = None | Cidr { ipv4address :: IPv4Address,
+ maskbits :: Maskbits }
+ deriving (Eq)
--- Will return True if the passed String is in CIDR notation, False
--- otherwise.
-is_valid_cidr :: String -> Bool
-is_valid_cidr cidr = cidr =~ "([0-9]{1,3}\\.){3}[0-9]{1,3}/[0-9]{1,2}"
-first :: (a,b,c,d) -> a
-first (w,_,_,_) = w
+instance Show Cidr where
+ show Cidr.None = "None"
+ show cidr = (show (ipv4address cidr)) ++ "/" ++ (show (maskbits cidr))
-second :: (a,b,c,d) -> b
-second (_,x,_,_) = x
-third :: (a,b,c,d) -> c
-third (_,_,y,_) = y
+instance Arbitrary Cidr where
+ arbitrary = do
+ ipv4 <- arbitrary :: Gen IPv4Address
+ mask <- arbitrary :: Gen Maskbits
+ return (Cidr ipv4 mask)
-fourth :: (a,b,c,d) -> d
-fourth (_,_,_,z) = z
+ coarbitrary _ = variant 0
-min_first_octet :: Cidr -> Octet
-min_first_octet cidr = first (min_octets cidr)
-min_second_octet :: Cidr -> Octet
-min_second_octet cidr = second (min_octets cidr)
+-- Two CIDR ranges are equivalent if they have the same network bits
+-- and the masks are the same.
+equivalent :: Cidr -> Cidr -> Bool
+equivalent Cidr.None Cidr.None = True
+equivalent Cidr.None _ = False
+equivalent _ Cidr.None = False
+equivalent (Cidr addr1 mbits1) (Cidr addr2 mbits2) =
+ (mbits1 == mbits2) && ((apply_mask addr1 mbits1 B.Zero) == (apply_mask addr2 mbits2 B.Zero))
-min_third_octet :: Cidr -> Octet
-min_third_octet cidr = third (min_octets cidr)
+-- Returns the mask portion of a CIDR address. That is, everything
+-- after the trailing slash.
+maskbits_from_cidr_string :: String -> Maskbits
+maskbits_from_cidr_string s =
+ maskbits_from_string ((splitWith (`elem` "/") s) !! 1)
-min_fourth_octet :: Cidr -> Octet
-min_fourth_octet cidr = fourth (min_octets cidr)
-max_first_octet :: Cidr -> Octet
-max_first_octet cidr = first (max_octets cidr)
+-- Takes an IP address String in CIDR notation, and returns a list of
+-- its octets (as Ints).
+octets_from_cidr_string :: String -> [Octet]
+octets_from_cidr_string s =
+ map octet_from_string (take 4 (splitWith (`elem` "./") s))
-max_second_octet :: Cidr -> Octet
-max_second_octet cidr = second (max_octets cidr)
-max_third_octet :: Cidr -> Octet
-max_third_octet cidr = third (max_octets cidr)
+cidr_from_string :: String -> Cidr
+cidr_from_string s
+ | addr == IPv4Address.None = Cidr.None
+ | mbits == Maskbits.None = Cidr.None
+ | otherwise = Cidr addr mbits
+ where
+ addr = ipv4address_from_octets (oct1) (oct2) (oct3) (oct4)
+ oct1 = (octs !! 0)
+ oct2 = (octs !! 1)
+ oct3 = (octs !! 2)
+ oct4 = (octs !! 3)
+ octs = octets_from_cidr_string s
+ mbits = maskbits_from_cidr_string s
+
+
+
+min_host :: Cidr -> IPv4Address
+min_host Cidr.None = IPv4Address.None
+min_host (Cidr IPv4Address.None _) = IPv4Address.None
+min_host (Cidr _ Maskbits.None) = IPv4Address.None
+min_host (Cidr addr mask) = apply_mask addr mask B.Zero
+
+
+max_host :: Cidr -> IPv4Address
+max_host Cidr.None = IPv4Address.None
+max_host (Cidr IPv4Address.None _) = IPv4Address.None
+max_host (Cidr _ Maskbits.None) = IPv4Address.None
+max_host (Cidr addr mask) = apply_mask addr mask B.One
+
+
+min_octet1 :: Cidr -> Octet
+min_octet1 cidr = octet1 (min_host cidr)
+
+min_octet2 :: Cidr -> Octet
+min_octet2 cidr = octet2 (min_host cidr)
+
+min_octet3 :: Cidr -> Octet
+min_octet3 cidr = octet3 (min_host cidr)
+
+min_octet4 :: Cidr -> Octet
+min_octet4 cidr = octet4 (min_host cidr)
+
+max_octet1 :: Cidr -> Octet
+max_octet1 cidr = octet1 (max_host cidr)
+
+max_octet2 :: Cidr -> Octet
+max_octet2 cidr = octet2 (max_host cidr)
+
+max_octet3 :: Cidr -> Octet
+max_octet3 cidr = octet3 (max_host cidr)
+
+max_octet4 :: Cidr -> Octet
+max_octet4 cidr = octet4 (max_host cidr)
+
+
+
+-- Return true if the first argument (a CIDR range) contains the
+-- second (another CIDR range). There are a lot of ways we can be fed
+-- junk here. For lack of a better alternative, just return False when
+-- we are given nonsense.
+contains :: Cidr -> Cidr -> Bool
+contains Cidr.None _ = False
+contains _ Cidr.None = False
+contains (Cidr _ Maskbits.None) _ = False
+contains (Cidr IPv4Address.None _) _ = False
+contains _ (Cidr _ Maskbits.None) = False
+contains _ (Cidr IPv4Address.None _) = False
+
+-- If the number of bits in the network part of the first address is
+-- larger than the number of bits in the second, there is no way that
+-- the first range can contain the second. For, if the number of
+-- network bits is larger, then the number of host bits must be
+-- smaller, and if cidr1 has fewer hosts than cidr2, cidr1 most
+-- certainly does not contain cidr2.
+--
+-- On the other hand, if the first argument (cidr1) has fewer (or the
+-- same number of) network bits as the second, it can contain the
+-- second. In this case, we need to check that every host in cidr2 is
+-- contained in cidr1. If a host in cidr2 is contained in cidr1, then
+-- at least mbits1 of an address in cidr2 will match cidr1. For
+-- example,
+--
+-- cidr1 = 192.168.1.0/23, cidr2 = 192.168.1.100/24
+--
+-- Here, cidr2 contains all of 192.168.1.0 through
+-- 192.168.1.255. However, cidr1 contains BOTH 192.168.0.0 through
+-- 192.168.0.255 and 192.168.1.0 through 192.168.1.255. In essence,
+-- what we want to check is that cidr2 "begins with" something that
+-- cidr1 CAN begin with. Since cidr1 can begin with 192.168.1, and
+-- cidr2 DOES, cidr1 contains cidr2..
+--
+-- The way that we check this is to apply cidr1's mask to cidr2's
+-- address and see if the result is the same as cidr1's mask applied
+-- to cidr1's address.
+--
+contains (Cidr addr1 mbits1) (Cidr addr2 mbits2)
+ | mbits1 > mbits2 = False
+ | otherwise = addr1masked == addr2masked
+ where
+ addr1masked = apply_mask addr1 mbits1 B.Zero
+ addr2masked = apply_mask addr2 mbits1 B.Zero
-max_fourth_octet :: Cidr -> Octet
-max_fourth_octet cidr = fourth (max_octets cidr)
+contains_proper :: Cidr -> Cidr -> Bool
+contains_proper cidr1 cidr2 =
+ (cidr1 `contains` cidr2) && (not (cidr2 `contains` cidr1))
--- Returns the mask portion of a CIDR address. That is, everything
--- after the trailing slash.
-maskbits_from_string :: String -> Maskbits
-maskbits_from_string s = read ((splitWith (`elem` "/") s) !! 1)
+-- A CIDR range is redundant (with respect to the given list) if
+-- another CIDR range in that list properly contains it.
+redundant :: [Cidr] -> Cidr -> Bool
+redundant cidrlist cidr = any ((flip contains_proper) cidr) cidrlist
--- Takes an IP address String in CIDR notation, and returns a list of
--- its octets (converted to Int).
-octets_from_string :: String -> [Octet]
-octets_from_string s = map read (take 4 (splitWith (`elem` "./") s))
+
+-- First, we look at all possible pairs of cidrs, and combine the
+-- adjacent ones in to a new list. Then, we concatenate that list with
+-- the original one, and filter out all of the redundancies. If two
+-- adjacent Cidrs are combined into a larger one, they will be removed
+-- in the second step since the larger Cidr must contain the smaller
+-- two.
+combine_all :: [Cidr] -> [Cidr]
+combine_all cidrs =
+ combine_contained unique_cidrs
+ where
+ unique_cidrs = nubBy equivalent valid_cidr_combinations
+ valid_cidr_combinations = filter (/= Cidr.None) cidr_combinations
+ cidr_combinations =
+ cidrs ++ [ (combine_adjacent x y) | x <- cidrs, y <- cidrs ]
+
+
+-- Take a list of CIDR ranges and filter out all of the ones that are
+-- contained entirelt within some other range in the list.
+combine_contained :: [Cidr] -> [Cidr]
+combine_contained cidrs =
+ filter (not . (redundant cidrs)) cidrs
+
+
+-- If the two Cidrs are not adjacent, return Cidr.None. Otherwise,
+-- decrement the maskbits of cidr1 and return that; it will contain
+-- both cidr1 and cidr2.
+combine_adjacent :: Cidr -> Cidr -> Cidr
+combine_adjacent cidr1 cidr2
+ | not (adjacent cidr1 cidr2) = Cidr.None
+ | (maskbits cidr1 == Zero) = Cidr.None
+ | otherwise = cidr1 { maskbits = decrement (maskbits cidr1) }
-from_string :: String -> Cidr
-from_string s = Cidr (octs !! 0) (octs !! 1) (octs !! 2) (octs !! 3) mbits
- where
- octs = octets_from_string s
- mbits = maskbits_from_string s
+-- Determine whether or not two CIDR ranges are adjacent. If two
+-- ranges lie consecutively within the IP space, they can be
+-- combined. For example, 10.1.0.0/24 and 10.0.1.0/24 are adjacent,
+-- and can be combined in to 10.1.0.0/23.
+adjacent :: Cidr -> Cidr -> Bool
+adjacent Cidr.None _ = False
+adjacent _ Cidr.None = False
+adjacent cidr1 cidr2
+ | mbits1 /= mbits2 = False
+ | mbits1 == Maskbits.Zero = False -- They're equal.
+ | otherwise = (mbits1 == (most_sig_bit_different addr1 addr2))
+ where
+ addr1 = ipv4address cidr1
+ addr2 = ipv4address cidr2
+ mbits1 = maskbits cidr1
+ mbits2 = maskbits cidr2
--- The base_two_to_base_ten function requires a way to determine
--- whether or not the character it's currently parsing is valid. This
--- should do it.
-is_binary_digit :: Char -> Bool
-is_binary_digit c =
- if c `elem` ['0','1'] then
- True
- else
- False
--- Takes an Int, and returns its base-two representation as a String.
-base_two :: Int -> String
-base_two n = showIntAtBase 2 intToDigit n ""
--- Takes a set of octets, and converts them to base-two
--- individually. The results are then zero-padded on the left to 8
--- characters, and concatenated together.
-octets_base_two :: Cidr -> String
-octets_base_two cidr =
- s1 ++ s2 ++ s3 ++ s4
+-- HUnit Tests
+
+test_equality1 :: Test
+test_equality1 =
+ TestCase $ assertEqual "10.1.1.0/23 equals itself" True (cidr1 == cidr1)
+ where
+ cidr1 = cidr_from_string "10.1.1.0/23"
+
+
+test_contains1 :: Test
+test_contains1 =
+ TestCase $ assertEqual "10.1.1.0/23 contains 10.1.1.0/24" True (cidr1 `contains` cidr2)
where
- s1 = ((pad_left_to 8 '0') . base_two) (octet1 cidr)
- s2 = ((pad_left_to 8 '0') . base_two) (octet2 cidr)
- s3 = ((pad_left_to 8 '0') . base_two) (octet3 cidr)
- s4 = ((pad_left_to 8 '0') . base_two) (octet4 cidr)
+ cidr1 = cidr_from_string "10.1.1.0/23"
+ cidr2 = cidr_from_string "10.1.1.0/24"
-base_two_octetlist_to_octetlist :: BaseTwoOctetList -> OctetList
-base_two_octetlist_to_octetlist b2ol =
- (oct1, oct2, oct3, oct4)
+test_contains2 :: Test
+test_contains2 =
+ TestCase $ assertEqual "10.1.1.0/23 contains itself" True (cidr1 `contains` cidr1)
where
- oct1 = base_two_to_base_ten (first b2ol)
- oct2 = base_two_to_base_ten (second b2ol)
- oct3 = base_two_to_base_ten (third b2ol)
- oct4 = base_two_to_base_ten (fourth b2ol)
-
-
--- Convert a base-two String to an Int.
-base_two_to_base_ten :: String -> Int
-base_two_to_base_ten s =
- if (length parsed) == 0 then
- 0
- else
- fst (parsed !! 0)
+ cidr1 = cidr_from_string "10.1.1.0/23"
+
+
+test_contains_proper1 :: Test
+test_contains_proper1 =
+ TestCase $ assertEqual "10.1.1.0/23 contains 10.1.1.0/24 properly" True (cidr1 `contains_proper` cidr2)
where
- parsed = readInt 2 is_binary_digit digitToInt s
+ cidr1 = cidr_from_string "10.1.1.0/23"
+ cidr2 = cidr_from_string "10.1.1.0/24"
--- Returns the minimum address (as a base-two string) satisfying the
--- given CIDR string.
-min_base_two_address :: Cidr -> String
-min_base_two_address cidr =
- pad_right_to 32 '0' netpart
+test_contains_proper2 :: Test
+test_contains_proper2 =
+ TestCase $ assertEqual "10.1.1.0/23 does not contain itself properly" False (cidr1 `contains_proper` cidr1)
where
- netpart = take (maskbits cidr) (octets_base_two cidr)
+ cidr1 = cidr_from_string "10.1.1.0/23"
--- Returns the maximum address (as a base-two string) satisfying the
--- given CIDR string.
-max_base_two_address :: Cidr -> String
-max_base_two_address cidr =
- pad_right_to 32 '1' netpart
+test_adjacent1 :: Test
+test_adjacent1 =
+ TestCase $ assertEqual "10.1.0.0/24 is adjacent to 10.1.1.0/24" True (cidr1 `adjacent` cidr2)
where
- netpart = take (maskbits cidr) (octets_base_two cidr)
+ cidr1 = cidr_from_string "10.1.0.0/24"
+ cidr2 = cidr_from_string "10.1.1.0/24"
--- The octet components of min_base_two_address, as a base-two String.
-min_base_two_octets :: Cidr -> BaseTwoOctetList
-min_base_two_octets cidr =
- (oct1, oct2, oct3, oct4)
+test_adjacent2 :: Test
+test_adjacent2 =
+ TestCase $ assertEqual "10.1.0.0/23 is not adjacent to 10.1.0.0/24" False (cidr1 `adjacent` cidr2)
where
- addr = min_base_two_address cidr
- oct1 = fst (splitAt 8 addr)
- oct2 = fst (splitAt 8 (snd (splitAt 8 addr)))
- oct3 = fst (splitAt 8 (snd (splitAt 16 addr)))
- oct4 = snd (splitAt 24 addr)
+ cidr1 = cidr_from_string "10.1.0.0/23"
+ cidr2 = cidr_from_string "10.1.0.0/24"
--- The octet components of max_base_two_address, as a base-two String.
-max_base_two_octets :: Cidr -> BaseTwoOctetList
-max_base_two_octets cidr =
- (oct1, oct2, oct3, oct4)
+test_adjacent3 :: Test
+test_adjacent3 =
+ TestCase $ assertEqual "10.1.0.0/24 is not adjacent to 10.2.5.0/24" False (cidr1 `adjacent` cidr2)
where
- addr = max_base_two_address cidr
- oct1 = fst (splitAt 8 addr)
- oct2 = fst (splitAt 8 (snd (splitAt 8 addr)))
- oct3 = fst (splitAt 8 (snd (splitAt 16 addr)))
- oct4 = snd (splitAt 24 addr)
+ cidr1 = cidr_from_string "10.1.0.0/24"
+ cidr2 = cidr_from_string "10.2.5.0/24"
--- The octet components of min_base_two_address, as Ints.
-min_octets :: Cidr -> OctetList
-min_octets cidr = base_two_octetlist_to_octetlist (min_base_two_octets cidr)
+test_adjacent4 :: Test
+test_adjacent4 =
+ TestCase $ assertEqual "10.1.1.0/24 is not adjacent to 10.1.2.0/24" False (cidr1 `adjacent` cidr2)
+ where
+ cidr1 = cidr_from_string "10.1.1.0/24"
+ cidr2 = cidr_from_string "10.1.2.0/24"
--- The octet components of max_base_two_address, as Ints.
-max_octets :: Cidr -> OctetList
-max_octets cidr = base_two_octetlist_to_octetlist (max_base_two_octets cidr)
+test_combine_contained1 :: Test
+test_combine_contained1 =
+ TestCase $ assertEqual "10.0.0.0/8, 10.1.0.0/16, and 10.1.1.0/24 combine to 10.0.0.0/8" expected_cidrs (combine_contained test_cidrs)
+ where
+ cidr1 = cidr_from_string "10.0.0.0/8"
+ cidr2 = cidr_from_string "10.1.0.0/16"
+ cidr3 = cidr_from_string "10.1.1.0/24"
+ expected_cidrs = [cidr1]
+ test_cidrs = [cidr1, cidr2, cidr3]
+
+
+test_combine_contained2 :: Test
+test_combine_contained2 =
+ TestCase $ assertEqual "192.168.3.0/23 does not contain 192.168.1.0/24" [cidr1, cidr2] (combine_contained [cidr1, cidr2])
+ where
+ cidr1 = cidr_from_string "192.168.3.0/23"
+ cidr2 = cidr_from_string "192.168.1.0/24"
+
+
+test_combine_all1 :: Test
+test_combine_all1 =
+ TestCase $ assertEqual "10.0.0.0/24 is adjacent to 10.0.1.0/24 and 10.0.3.0/23 contains 10.0.2.0/24" expected_cidrs (combine_all test_cidrs)
+ where
+ cidr1 = cidr_from_string "10.0.0.0/24"
+ cidr2 = cidr_from_string "10.0.1.0/24"
+ cidr3 = cidr_from_string "10.0.2.0/24"
+ cidr4 = cidr_from_string "10.0.3.0/23"
+ cidr5 = cidr_from_string "10.0.0.0/23"
+ expected_cidrs = [cidr4, cidr5]
+ test_cidrs = [cidr1, cidr2, cidr3, cidr4]
+
+
+test_combine_all2 :: Test
+test_combine_all2 =
+ TestCase $ assertEqual "127.0.0.1/32 combines with itself recursively" expected_cidrs (combine_all test_cidrs)
+ where
+ cidr1 = cidr_from_string "127.0.0.1/32"
+ expected_cidrs = [cidr1]
+ test_cidrs = [cidr1, cidr1, cidr1, cidr1, cidr1]
+
+
+cidr_tests :: [Test]
+cidr_tests = [ test_equality1,
+ test_contains1,
+ test_contains2,
+ test_contains_proper1,
+ test_contains_proper2,
+ test_adjacent1,
+ test_adjacent2,
+ test_adjacent3,
+ test_adjacent4,
+ test_combine_contained1,
+ test_combine_contained2,
+ test_combine_all1,
+ test_combine_all2
+ ]
+
+
+-- QuickCheck Tests
+prop_all_cidrs_contain_themselves :: Cidr -> Bool
+prop_all_cidrs_contain_themselves cidr1 = cidr1 `contains` cidr1
+
+
+-- If cidr1 properly contains cidr2, then by definition cidr2
+-- does not properly contain cidr1.
+prop_contains_proper_intransitive :: Cidr -> Cidr -> Property
+prop_contains_proper_intransitive cidr1 cidr2 =
+ (cidr1 `contains_proper` cidr2) ==>
+ (not (cidr2 `contains_proper` cidr1))
projects / hath.git / blobdiff