module Examples.IP where

import Data.Codec
import Data.Binary.Bits.Codec
import Data.Word

data IPv4 = IPv4
  { version :: Word8
  , ihl :: Word8
  , dscp :: Word8
  , ecn :: Word8
  , totalLength :: Word16
  , identification :: Word16
  , flags :: Word8
  , fragmentOffset :: Word16
  , timeToLive :: Word8
  , protocol :: Word8
  , headerChecksum :: Word16
  , sourceIP :: Word32
  , destIP :: Word32
  }

genFields ''IPv4

ipv4Codec :: BitCodec IPv4
ipv4Codec = 
  IPv4
    $>> f_version        >-< word8 4
    >>> f_ihl            >-< word8 4
    >>> f_dscp           >-< word8 6
    >>> f_ecn            >-< word8 2
    >>> f_totalLength    >-< word16be 16
    >>> f_identification >-< word16be 16
    >>> f_flags          >-< word8 3
    >>> f_fragmentOffset >-< word16be 13
    >>> f_timeToLive     >-< word8 8
    >>> f_protocol       >-< word8 8
    >>> f_headerChecksum >-< word16be 16
    >>> f_sourceIP       >-< word32be 32
    >>> f_destIP         >-< word32be 32