Types for IP address and prefix

1 files changed, 45 insertions, 0 deletions

diff --git a/src/Network/Ip.hs b/src/Network/Ip.hs
new file mode 100644
index 0000000..76cc8f4
--- /dev/null
+++ b/src/Network/Ip.hs
@@ -0,0 +1,45 @@
+module Network.Ip (
+    IpPrefix(..),
+    textIpNetwork,
+
+    IpAddress(..),
+    textIpAddress,
+    textIpAddressCidr,
+
+    allowsSubnets,
+    ipSubnet,
+    lanSubnet,
+) where
+
+import Data.Text (Text)
+import Data.Text qualified as T
+import Data.Word
+
+newtype IpPrefix = IpPrefix [Word8]
+    deriving (Eq, Ord)
+
+textIpNetwork :: IpPrefix -> Text
+textIpNetwork (IpPrefix prefix) =
+    T.intercalate "." (map (T.pack . show) $ prefix ++ replicate (4 - length prefix) 0)
+    <> "/" <> T.pack (show (8 * length prefix))
+
+data IpAddress = IpAddress IpPrefix Word8
+    deriving (Eq, Ord)
+
+textIpAddress :: IpAddress -> Text
+textIpAddress (IpAddress (IpPrefix prefix) num) =
+    T.intercalate "." $ map (T.pack . show) $ prefix ++ replicate (3 - length prefix) 0 ++ [num]
+
+textIpAddressCidr :: IpAddress -> Text
+textIpAddressCidr ip@(IpAddress (IpPrefix prefix) _) =
+    textIpAddress ip <> "/" <> T.pack (show (8 * length prefix))
+
+allowsSubnets :: IpPrefix -> Bool
+allowsSubnets (IpPrefix prefix) = length prefix < 3
+
+ipSubnet :: Word8 -> IpPrefix -> IpPrefix
+ipSubnet num (IpPrefix prefix) = IpPrefix (prefix ++ [num])
+
+lanSubnet :: IpPrefix -> IpPrefix
+lanSubnet (IpPrefix prefix) = IpPrefix (take 3 $ prefix ++ repeat 0)
+