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module Network.Ip (
IpPrefix(..),
textIpNetwork,
IpAddress(..),
textIpAddress,
textIpAddressCidr,
allowsSubnets,
ipSubnet,
lanSubnet,
MonadPIO(..),
MonadSTM(..),
atomicallyWithIO,
NetworkNamespace,
HasNetns(..),
addNetworkNamespace,
textNetnsName,
callOn,
Link(..),
Loopback, loopback,
VEth, addVEth,
Bridge, addBridge,
addAddress,
setMaster,
linkUp, linkDown,
Route(..),
addRoute,
) where
import Control.Concurrent.STM
import Control.Monad.Writer
import Data.Function
import Data.Text (Text)
import Data.Text qualified as T
import Data.Typeable
import Data.Word
import System.Process
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)
class Monad m => MonadPIO m where
postpone :: IO () -> m ()
instance MonadPIO IO where
postpone = id
instance Monad m => MonadPIO (WriterT [IO ()] m) where
postpone = tell . (:[])
class Monad m => MonadSTM m where
liftSTM :: STM a -> m a
instance MonadSTM STM where
liftSTM = id
instance MonadSTM m => MonadSTM (WriterT [IO ()] m) where
liftSTM = lift . liftSTM
atomicallyWithIO :: MonadIO m => WriterT [IO ()] STM a -> m a
atomicallyWithIO act = liftIO $ do
(x, fin) <- atomically $ runWriterT act
sequence_ fin
return x
data NetworkNamespace = NetworkNamespace
{ netnsName :: Text
, netnsRoutesConfigured :: TVar [Route]
, netnsRoutesActive :: TVar [Route]
}
instance Eq NetworkNamespace where
(==) = (==) `on` netnsName
instance Ord NetworkNamespace where
compare = compare `on` netnsName
class HasNetns a where getNetns :: a -> NetworkNamespace
instance HasNetns NetworkNamespace where getNetns = id
addNetworkNamespace :: (MonadPIO m, MonadSTM m) => Text -> m NetworkNamespace
addNetworkNamespace netnsName = do
postpone $ callCommand $ T.unpack $ "ip netns add \"" <> netnsName <> "\""
netnsRoutesConfigured <- liftSTM $ newTVar []
netnsRoutesActive <- liftSTM $ newTVar []
return $ NetworkNamespace {..}
textNetnsName :: NetworkNamespace -> Text
textNetnsName = netnsName
callOn :: HasNetns a => a -> Text -> IO ()
callOn n cmd = callCommand $ T.unpack $ "ip netns exec \"" <> ns <> "\" " <> cmd
where ns = textNetnsName $ getNetns n
data Link a = Link
{ linkName :: Text
, linkNetns :: NetworkNamespace
}
deriving (Eq)
data SomeLink = forall a. Typeable a => SomeLink (Link a)
instance Eq SomeLink where
SomeLink a == SomeLink b
| Just b' <- cast b = a == b'
| otherwise = False
liftSomeLink :: (forall a. Link a -> b) -> SomeLink -> b
liftSomeLink f (SomeLink x) = f x
instance HasNetns (Link a) where getNetns = linkNetns
instance HasNetns SomeLink where getNetns = liftSomeLink linkNetns
data Loopback
loopback :: HasNetns n => n -> Link Loopback
loopback = Link "lo" . getNetns
data VEth
addVEth :: (HasNetns n, HasNetns n', MonadPIO m) => (n, Text) -> (n', Text) -> m (Link VEth, Link VEth)
addVEth (netns, name) (netns', name') = do
postpone $ callOn netns $ "ip link add \"" <> name <> "\" type veth peer name \"" <> name' <> "\" netns \"" <> textNetnsName (getNetns netns') <> "\""
return $ (,)
(Link name $ getNetns netns )
(Link name' $ getNetns netns')
data Bridge
addBridge :: (HasNetns n, MonadPIO m) => n -> Text -> m (Link Bridge)
addBridge netns name = do
postpone $ callOn netns $ "ip link add name \"" <> name <> "\" type bridge"
return $ Link name $ getNetns netns
addAddress :: MonadPIO m => Link a -> IpAddress -> m ()
addAddress link addr@(IpAddress prefix _) = do
let bcast = IpAddress prefix 255
postpone $ callOn link $ "ip addr add " <> textIpAddressCidr addr <> " broadcast " <> textIpAddress bcast <> " dev \"" <> linkName link <> "\""
setMaster :: MonadPIO m => Link a -> Link Bridge -> m ()
setMaster link bridge = postpone $ do
when (getNetns link /= getNetns bridge) $ fail "link and bridge in different network namespaces"
callOn link $ "ip link set dev \"" <> linkName link <> "\" master \"" <> linkName bridge <> "\""
linkUp :: (Typeable a, MonadPIO m, MonadSTM m) => Link a -> m ()
linkUp link = do
routes <- liftSTM $ filter ((== SomeLink link) . routeDev) <$> readTVar (netnsRoutesConfigured (getNetns link))
liftSTM $ modifyTVar (netnsRoutesActive (getNetns link)) $ (routes ++)
postpone $ do
callOn link $ "ip link set dev \"" <> linkName link <> "\" up"
-- add back routes that were automatically removed by kernel when the link went down
mapM_ applyRoute routes
linkDown :: (Typeable a, MonadPIO m, MonadSTM m) => Link a -> m ()
linkDown link = do
-- routes using this device will be automatically removed by kernel
liftSTM $ modifyTVar (netnsRoutesActive (getNetns link)) $ filter ((/= SomeLink link) . routeDev)
postpone $ callOn link $ "ip link set dev \"" <> linkName link <> "\" down"
data Route = Route
{ routePrefix :: IpPrefix
, routeVia :: IpAddress
, routeDev :: SomeLink
, routeSrc :: IpAddress
}
addRoute :: Typeable a => IpPrefix -> IpAddress -> Link a -> IpAddress -> WriterT [IO ()] STM ()
addRoute routePrefix routeVia link routeSrc = do
let routeDev = SomeLink link
route = Route {..}
lift $ do
modifyTVar (netnsRoutesConfigured (getNetns link)) (route:)
modifyTVar (netnsRoutesActive (getNetns link)) (route:)
postpone $ applyRoute route
applyRoute :: Route -> IO ()
applyRoute route = callOn (routeDev route) $ "ip route add "
<> textIpNetwork (routePrefix route)
<> " via " <> textIpAddress (routeVia route)
<> " dev " <> linkName `liftSomeLink` (routeDev route)
<> " src " <> textIpAddress (routeSrc route)
|