src/Cidr.hs

   1 module Cidr
   2 ( Cidr(..),
   3   cidr_from_string,
   4   is_valid_cidr
   5 ) where
   6
   7 import Text.Regex.Posix
   8
   9 import IPv4Address
  10 import ListUtils
  11 import Octet
  12
  13
  14 data Cidr = None | Cidr { ipv4address :: IPv4Address,
  15                           maskbits :: Maskbits }
  16             deriving (Eq, Show)
  17
  18 -- Will return True if the passed String is in CIDR notation, False
  19 -- otherwise.
  20 is_valid_cidr :: String -> Bool
  21 is_valid_cidr cidr = cidr =~ "([0-9]{1,3}\\.){3}[0-9]{1,3}/[0-9]{1,2}"
  22
  23
  24 -- Returns the mask portion of a CIDR address. That is, everything
  25 -- after the trailing slash.
  26 maskbits_from_string :: String -> Maskbits
  27 maskbits_from_string s = read ((splitWith (`elem` "/") s) !! 1)
  28
  29
  30 -- Takes an IP address String in CIDR notation, and returns a list of
  31 -- its octets (as Ints).
  32 octets_from_string :: String -> [Int]
  33 octets_from_string s = map read (take 4 (splitWith (`elem` "./") s))
  34
  35
  36 cidr_from_string :: String -> Cidr
  37 cidr_from_string s
  38     | addr == IPv4Address.None = Cidr.None
  39     | otherwise = Cidr addr mbits
  40                where
  41                  addr = ipv4address_from_octets (oct1) (oct2) (oct3) (oct4)
  42                  oct1 = octet_from_int (octs !! 0)
  43                  oct2 = octet_from_int (octs !! 1)
  44                  oct3 = octet_from_int (octs !! 2)
  45                  oct4 = octet_from_int (octs !! 3)
  46                  octs  = octets_from_string s
  47                  mbits = maskbits_from_string s