Added more network interface configuration properties.

config-joey.hs

@@ -141,6 +141,7 @@ kite = standardSystemUnhardened "kite.kitenet.net" Testing "amd64"
 		, (SshEd25519, "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIFZftKMnH/zH29BHMKbcBO4QsgTrstYFVhbrzrlRzBO3")
 		]
 
+	& Network.static "eth0" `requires` Network.cleanInterfacesFile
 	& Apt.installed ["linux-image-amd64"]
 	& Linode.chainPVGrub 5
 	& Apt.unattendedUpgrades

debian/changelog

@@ -7,6 +7,7 @@ propellor (1.4.0) UNRELEASED; urgency=medium
   * Fix info propigation from fallback combinator's second Property.
   * Added systemd configuration properties.
   * Added journald configuration properties.
+  * Added more network interface configuration properties.
 
  -- Joey Hess <id@joeyh.name>  Thu, 15 Jan 2015 20:14:29 -0400
 

src/Propellor/Property/Network.hs

@@ -5,21 +5,73 @@ import Propellor.Property.File
 
 type Interface = String
 
-interfaces :: FilePath
-interfaces = "/etc/network/interfaces"
+ifUp :: Interface -> Property
+ifUp iface = cmdProperty "ifup" [iface]
 
-interfaceFile :: Interface -> FilePath
-interfaceFile iface = "/etc/network/interfaces.d" </> iface
+-- | Resets /etc/network/interfaces to a clean and empty state,
+-- containing just the standard loopback interface, and with
+-- interfacesD enabled.
+--
+-- This can be used as a starting point to defining other interfaces.
+--
+-- No interfaces are brought up or down by this property.
+cleanInterfacesFile :: Property
+cleanInterfacesFile = hasContent interfacesFile
+	[ "# Deployed by propellor, do not edit."
+	, ""
+	, "source-directory interfaces.d"
+	, ""
+	, "# The loopback network interface"
+	, "auto lo"
+	, "iface lo inet loopback"
+	]
+	`describe` ("clean " ++ interfacesFile)
 
--- | Enable source-directory interfaces.d
-interfacesD :: Property
-interfacesD = containsLine interfaces "source-directory interfaces.d"
-	`describe` "interfaces.d directory enabled"
+-- | Writes a static interface file for the specified interface.
+--
+-- The interface has to be up already. It could have been brought up by
+-- DHCP, or by other means. The current ipv4 addresses
+-- and routing configuration of the interface are written into the file.
+--
+-- If the interface file already exists, this property does nothing,
+-- no matter its content.
+-- 
+-- (ipv6 addresses are not included because it's assumed they come up
+-- automatically in most situations.)
+static :: Interface -> Property
+static iface = check (not <$> doesFileExist f) setup
+	`describe` desc
+	`requires` interfacesDEnabled
+  where
+	f = interfaceDFile iface
+	desc = "static " ++ iface
+	setup = property desc $ do
+		ls <- liftIO $ lines <$> readProcess "ip"
+			["-o", "addr", "show", iface, "scope", "global"]
+		stanzas <- liftIO $ concat <$> mapM mkstanza ls
+		ensureProperty $ hasContent f $ ("auto " ++ iface) : stanzas
+	mkstanza ipline = case words ipline of
+		-- Note that the IP address is written CIDR style, so
+		-- the netmask does not need to be specified separately.
+		(_:iface':"inet":addr:_) | iface' == iface -> do
+			gw <- getgateway
+			return $ catMaybes
+				[ Just $ "iface " ++ iface ++ " inet static"
+				, Just $ "\taddress " ++ addr
+				, ("\tgateway " ++) <$> gw
+				]
+		_ -> return []
+	getgateway = do
+		rs <- lines <$> readProcess "ip"
+			["route", "show", "scope", "global", "dev", iface]
+		return $ case words <$> headMaybe rs of
+			Just ("default":"via":gw:_) -> Just gw
+			_ -> Nothing
 
 -- | 6to4 ipv6 connection, should work anywhere
 ipv6to4 :: Property
-ipv6to4 = hasContent (interfaceFile "sit0")
-	[ "# Automatically added by propeller"
+ipv6to4 = hasContent (interfaceDFile "sit0")
+	[ "# Deployed by propellor, do not edit."
 	, "iface sit0 inet6 static"
 	, "\taddress 2002:5044:5531::1"
 	, "\tnetmask 64"
@@ -27,8 +79,17 @@ ipv6to4 = hasContent (interfaceFile "sit0")
 	, "auto sit0"
 	]
 	`describe` "ipv6to4"
-	`requires` interfacesD
+	`requires` interfacesDEnabled
 	`onChange` ifUp "sit0"
 
-ifUp :: Interface -> Property
-ifUp iface = cmdProperty "ifup" [iface]
+interfacesFile :: FilePath
+interfacesFile = "/etc/network/interfaces"
+
+-- | A file in the interfaces.d directory.
+interfaceDFile :: Interface -> FilePath
+interfaceDFile iface = "/etc/network/interfaces.d" </> iface
+
+-- | Ensures that files in the the interfaces.d directory are used.
+interfacesDEnabled :: Property
+interfacesDEnabled = containsLine interfacesFile "source-directory interfaces.d"
+	`describe` "interfaces.d directory enabled"