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,
+ contains
) where
-import Data.Char (digitToInt, intToDigit)
-import Numeric (readInt, showIntAtBase)
-import Text.Regex.Posix
-
+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)
-
--- 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
-
-second :: (a,b,c,d) -> b
-second (_,x,_,_) = x
-
-third :: (a,b,c,d) -> c
-third (_,_,y,_) = y
-
-fourth :: (a,b,c,d) -> d
-fourth (_,_,_,z) = z
-
-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)
-
-min_third_octet :: Cidr -> Octet
-min_third_octet cidr = third (min_octets cidr)
-
-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)
-
-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)
-
-max_fourth_octet :: Cidr -> Octet
-max_fourth_octet cidr = fourth (max_octets cidr)
+data Cidr = None | Cidr { ipv4address :: IPv4Address,
+ maskbits :: Maskbits }
+ deriving (Eq, Show)
-- 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)
+maskbits_from_cidr_string :: String -> Maskbits
+maskbits_from_cidr_string s =
+ maskbits_from_string ((splitWith (`elem` "/") s) !! 1)
-- 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))
+-- its octets (as Ints).
+octets_from_cidr_string :: String -> [Octet]
+octets_from_cidr_string s =
+ map octet_from_string (take 4 (splitWith (`elem` "./") s))
-from_string :: String -> Cidr
-from_string s = Cidr (octs !! 0) (octs !! 1) (octs !! 2) (octs !! 3) mbits
+cidr_from_string :: String -> Cidr
+cidr_from_string s
+ | addr == IPv4Address.None = Cidr.None
+ | mbits == Maskbits.None = Cidr.None
+ | otherwise = Cidr addr mbits
where
- octs = octets_from_string s
- mbits = maskbits_from_string s
-
-
--- 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
- 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)
-
-
-base_two_octetlist_to_octetlist :: BaseTwoOctetList -> OctetList
-base_two_octetlist_to_octetlist b2ol =
- (oct1, oct2, oct3, oct4)
- 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)
- where
- parsed = readInt 2 is_binary_digit digitToInt s
-
-
--- 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
- where
- netpart = take (maskbits cidr) (octets_base_two cidr)
-
-
--- 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
+ 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
+
+
+
+-- 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 (Maskbits mbits1)) (Cidr addr2 (Maskbits mbits2))
+ | mbits1 > mbits2 = False
+ | otherwise = addr1masked == addr2masked
where
- netpart = take (maskbits cidr) (octets_base_two cidr)
-
-
--- 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)
- 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)
-
-
--- 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)
- 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)
-
-
--- 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)
-
-
--- 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)
+ addr1masked = apply_mask addr1 (Maskbits mbits1)
+ addr2masked = apply_mask addr2 (Maskbits mbits1)
projects / hath.git / blobdiff