src/Main.hs

   1 module Main
   2 where
   3
   4 import Control.Concurrent.ParallelIO.Global (
   5   parallel,
   6   stopGlobalPool )
   7 import Control.Monad (unless, when)
   8 import qualified Data.ByteString.Char8 as BS (intercalate, pack, unpack)
   9 import Data.List ((\\), intercalate)
  10 import Data.Maybe (catMaybes, isNothing)
  11 import Data.String.Utils (splitWs)
  12 import System.Exit (ExitCode(..), exitSuccess, exitWith)
  13 import System.IO (stderr, hPutStrLn)
  14
  15 import Cidr (
  16   Cidr(..),
  17   cidr_from_string,
  18   combine_all,
  19   enumerate,
  20   max_octet1,
  21   max_octet2,
  22   max_octet3,
  23   max_octet4,
  24   min_octet1,
  25   min_octet2,
  26   min_octet3,
  27   min_octet4 )
  28 import CommandLine (
  29   help_set,
  30   help_text,
  31   input_function,
  32   Mode(..),
  33   parse_errors,
  34   parse_mode )
  35 import DNS (Domain, lookup_ptrs)
  36 import ExitCodes ( exit_args_parse_failed, exit_invalid_cidr )
  37 import Octet ()
  38
  39
  40 -- | A regular expression that matches a non-address character.
  41 non_addr_char :: String
  42 non_addr_char = "[^\\.0-9]"
  43
  44
  45 -- | Add non_addr_chars on either side of the given String. This
  46 --   prevents (for example) the regex '127.0.0.1' from matching
  47 --   '127.0.0.100'.
  48 addr_barrier :: String -> String
  49 addr_barrier x = non_addr_char ++ x ++ non_addr_char
  50
  51
  52 -- | The magic happens here. We take a CIDR String as an argument, and
  53 --   return the equivalent regular expression. We do this as follows:
  54 --
  55 --   1. Compute the minimum possible value of each octet.
  56 --   2. Compute the maximum possible value of each octet.
  57 --   3. Generate a regex matching every value between those min and
  58 --      max values.
  59 --   4. Join the regexes from step 3 with regexes matching periods.
  60 --   5. Stick an address boundary on either side of the result.
  61 cidr_to_regex :: Cidr.Cidr -> String
  62 cidr_to_regex cidr =
  63     addr_barrier (intercalate "\\." [range1, range2, range3, range4])
  64     where
  65       range1 = numeric_range min1 max1
  66       range2 = numeric_range min2 max2
  67       range3 = numeric_range min3 max3
  68       range4 = numeric_range min4 max4
  69       min1   = fromEnum (min_octet1 cidr)
  70       min2   = fromEnum (min_octet2 cidr)
  71       min3   = fromEnum (min_octet3 cidr)
  72       min4   = fromEnum (min_octet4 cidr)
  73       max1   = fromEnum (max_octet1 cidr)
  74       max2   = fromEnum (max_octet2 cidr)
  75       max3   = fromEnum (max_octet3 cidr)
  76       max4   = fromEnum (max_octet4 cidr)
  77
  78
  79
  80 -- | Take a list of Strings, and return a regular expression matching
  81 --   any of them.
  82 alternate :: [String] -> String
  83 alternate terms = "(" ++ (intercalate "|" terms) ++ ")"
  84
  85
  86 -- | Take two Ints as parameters, and return a regex matching any
  87 --   integer between them (inclusive).
  88 numeric_range :: Int -> Int -> String
  89 numeric_range x y =
  90     alternate (map show [lower..upper])
  91      where
  92        lower = minimum [x,y]
  93        upper = maximum [x,y]
  94
  95
  96 main :: IO ()
  97 main = do
  98   -- First, check for any errors that occurred while parsing
  99   -- the command line options.
 100   errors <- CommandLine.parse_errors
 101   unless (null errors) $ do
 102     hPutStrLn stderr (concat errors)
 103     putStrLn CommandLine.help_text
 104     exitWith (ExitFailure exit_args_parse_failed)
 105
 106   -- Next, check to see if the 'help' option was passed to the
 107   -- program. If it was, display the help, and exit successfully.
 108   help_opt_set <- CommandLine.help_set
 109   when help_opt_set $ do
 110     putStrLn CommandLine.help_text
 111     exitSuccess
 112
 113   -- The input function we receive here should know what to read.
 114   inputfunc <- (CommandLine.input_function)
 115   input <- inputfunc
 116
 117   let cidr_strings = splitWs input
 118   let cidrs = map cidr_from_string cidr_strings
 119
 120   when (any isNothing cidrs) $ do
 121     putStrLn "Error: not valid CIDR notation."
 122     exitWith (ExitFailure exit_invalid_cidr)
 123
 124   -- Filter out only the valid ones.
 125   let valid_cidrs = catMaybes cidrs
 126
 127   -- Get the mode of operation.
 128   mode <- CommandLine.parse_mode
 129
 130   case mode of
 131     Regex -> do
 132       let regexes = map cidr_to_regex valid_cidrs
 133       putStrLn $ alternate regexes
 134     Reduce ->
 135       mapM_ print (combine_all valid_cidrs)
 136     Dupe ->
 137        mapM_ print dupes
 138        where
 139          dupes = valid_cidrs \\ (combine_all valid_cidrs)
 140     Diff -> do
 141        mapM_ putStrLn deletions
 142        mapM_ putStrLn additions
 143        where
 144          dupes = valid_cidrs \\ (combine_all valid_cidrs)
 145          deletions = map (\s -> '-' : (show s)) dupes
 146          newcidrs = (combine_all valid_cidrs) \\ valid_cidrs
 147          additions = map (\s -> '+' : (show s)) newcidrs
 148     List -> do
 149       let combined_cidrs = combine_all valid_cidrs
 150       let addrs = concatMap enumerate combined_cidrs
 151       mapM_ print addrs
 152     Reverse -> do
 153       let combined_cidrs = combine_all valid_cidrs
 154       let addrs = concatMap enumerate combined_cidrs
 155       let addr_bytestrings = map (BS.pack . show) addrs
 156       ptrs <- lookup_ptrs addr_bytestrings
 157       let pairs = zip addr_bytestrings ptrs
 158       _ <- parallel (map (putStrLn . show_pair) pairs)
 159       return ()
 160
 161   stopGlobalPool
 162
 163   where
 164     show_pair :: (Domain, Maybe [Domain]) -> String
 165     show_pair (s, mds) =
 166       (BS.unpack s) ++ ": " ++ results
 167       where
 168         space = BS.pack " "
 169         results =
 170           case mds of
 171             Nothing -> ""
 172             Just ds -> BS.unpack $ BS.intercalate space ds