From dab23fd7890ea2c27096015bb49ec526fafa14c7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Tue, 25 Apr 2023 22:07:43 +0200
Subject: Link type and associated functions

---
 src/Network/Ip.hs | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 70 insertions(+), 4 deletions(-)

(limited to 'src/Network/Ip.hs')

diff --git a/src/Network/Ip.hs b/src/Network/Ip.hs
index 1365f66..13fc284 100644
--- a/src/Network/Ip.hs
+++ b/src/Network/Ip.hs
@@ -10,14 +10,22 @@ module Network.Ip (
     ipSubnet,
     lanSubnet,
 
+    MonadPIO(..),
+
     NetworkNamespace,
     HasNetns(..),
     addNetworkNamespace,
     textNetnsName,
     callOn,
-) where
 
-import Control.Concurrent.STM
+    Link(..),
+    Loopback, loopback,
+    VEth, addVEth,
+    Bridge, addBridge,
+    addAddress,
+    setMaster,
+    linkUp, linkDown,
+) where
 
 import Control.Monad.Writer
 
@@ -56,16 +64,27 @@ 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 . (:[])
+
+
 newtype NetworkNamespace = NetworkNamespace
     { netnsName :: Text
     }
     deriving (Eq, Ord)
 
 class HasNetns a where getNetns :: a -> NetworkNamespace
+instance HasNetns NetworkNamespace where getNetns = id
 
-addNetworkNamespace :: Text -> WriterT [IO ()] STM NetworkNamespace
+addNetworkNamespace :: MonadPIO m => Text -> m NetworkNamespace
 addNetworkNamespace name = do
-    tell $ (:[]) $ callCommand $ T.unpack $ "ip netns add \"" <> name <> "\""
+    postpone $ callCommand $ T.unpack $ "ip netns add \"" <> name <> "\""
     return $ NetworkNamespace
         { netnsName = name
         }
@@ -76,3 +95,50 @@ textNetnsName = netnsName
 callOn :: HasNetns a => a -> Text -> IO ()
 callOn n cmd = callCommand $ T.unpack $ "ip netns exec \"" <> ns <> "\" " <> cmd
     where NetworkNamespace ns = getNetns n
+
+
+data Link a = Link
+    { linkName :: Text
+    , linkNetns :: NetworkNamespace
+    }
+
+instance HasNetns (Link a) where getNetns = 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, MonadFail m) => Link a -> Link Bridge -> m ()
+setMaster link bridge = do
+    when (getNetns link /= getNetns bridge) $ fail "link and bridge in different network namespaces"
+    postpone $ callOn link $ "ip link set dev \"" <> linkName link <> "\" master \"" <> linkName bridge <> "\""
+
+linkUp :: MonadPIO m => Link a -> m ()
+linkUp link = do
+    postpone $ callOn link $ "ip link set dev \"" <> linkName link <> "\" up"
+
+linkDown :: MonadPIO m => Link a -> m ()
+linkDown link = do
+    postpone $ callOn link $ "ip link set dev \"" <> linkName link <> "\" down"
-- 
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