change vserver ID representation type to Word8

- performance improvement: avoid unnecessary representation and
  conversion from/to Integer
- part of hot path: with k-choices, all possible IDs are regularly
  generated and checked
- preparation for #74

src/Hash2Pub/ASN1Coding.hs

@@ -206,7 +206,7 @@ encodeNodeState ns = [
   , OctetString (ipAddrAsBS $ getIpAddr ns)
   , IntVal (toInteger . getDhtPort $ ns)
   , IntVal (toInteger . getServicePort $ ns)
-  , IntVal (getVServerID ns)
+  , IntVal (toInteger $ getVServerID ns)
   , End Sequence
                      ]
 
@@ -370,7 +370,7 @@ parseNodeState = onNextContainer Sequence $ do
       , domain = domain'
       , dhtPort = dhtPort'
       , servicePort = servicePort'
-      , vServerID = vServer'
+      , vServerID = fromInteger vServer'
       , ipAddr = ip'
                      }
 

src/Hash2Pub/DHTProtocol.hs

@@ -313,7 +313,7 @@ handleIncomingRequest nsSTM sendQ msgSet sourceAddr = do
             aRequestPart = Set.elemAt 0 msgSet
             senderNs = sender aRequestPart
             givenSenderID = getNid senderNs
-            recomputedID = genNodeID addr (getDomain senderNs) (fromInteger $ getVServerID senderNs)
+            recomputedID = genNodeID addr (getDomain senderNs) (getVServerID senderNs)
           in
           if recomputedID == givenSenderID
              then Just <$> responder nsSTM' msgSet'
@@ -779,7 +779,7 @@ requestPing ns target = do
             -- recompute ID for each received node and mark as verified in cache
             now <- getPOSIXTime
             forM_ responseVss (\vs ->
-                let recomputedID = genNodeID peerAddr (getDomain vs) (fromInteger $ getVServerID vs)
+                let recomputedID = genNodeID peerAddr (getDomain vs) (getVServerID vs)
                  in if recomputedID == getNid vs
                        then atomically $ writeTQueue (cacheWriteQueue ns) $ addNodeAsVerifiedPure now vs
                        else pure ()

src/Hash2Pub/FediChord.hs

@@ -151,7 +151,7 @@ fediChordInit initConf serviceRunner = do
 -- this function.
 fediChordJoinNewVs :: (MonadError String m, MonadIO m, Service s (RealNodeSTM s))
                      => RealNodeSTM s   -- ^ parent real node
-                     -> Integer         -- ^ vserver ID
+                     -> Word8           -- ^ vserver ID
                      -> RemoteNodeState -- ^ target node to join on
                      -> m (NodeID, LocalNodeStateSTM s)     -- ^ on success: (vserver ID, TVar of vserver)
 fediChordJoinNewVs nodeSTM vsId target = do
@@ -164,7 +164,7 @@ fediChordJoinNewVs nodeSTM vsId target = do
 
 -- | initialises the 'NodeState' for this local node.
 -- Separated from 'fediChordInit' to be usable in tests.
-nodeStateInit :: Service s (RealNodeSTM s) => RealNodeSTM s -> Integer -> IO (LocalNodeState s)
+nodeStateInit :: Service s (RealNodeSTM s) => RealNodeSTM s -> Word8 -> IO (LocalNodeState s)
 nodeStateInit realNodeSTM vsID' = do
     realNode <- readTVarIO realNodeSTM
     let
@@ -173,7 +173,7 @@ nodeStateInit realNodeSTM vsID' = do
         containedState = RemoteNodeState {
             domain = confDomain conf
           , ipAddr = confIP conf
-          , nid = genNodeID (confIP conf) (confDomain conf) $ fromInteger vsID
+          , nid = genNodeID (confIP conf) (confDomain conf) vsID
           , dhtPort = toEnum $ confDhtPort conf
           , servicePort = getListeningPortFromService $ nodeService realNode
           , vServerID = vsID
@@ -257,7 +257,7 @@ kChoicesVsJoin queryVsSTM bootstrapNode capacity activeVss nodeSTM remainingTarg
         activeVsSet = HMap.keysSet activeVss
         -- tuples of node IDs and vserver IDs, because vserver IDs are needed for
         -- LocalNodeState creation
-        nonJoinedIDs = filter (not . flip HSet.member activeVsSet . fst) [ (genNodeID (confIP conf) (confDomain conf) (fromInteger v), v) | v <- [0..pred (confKChoicesMaxVS conf)]]
+        nonJoinedIDs = filter (not . flip HSet.member activeVsSet . fst) [ (genNodeID (confIP conf) (confDomain conf) v, v) | v <- [0..pred (confKChoicesMaxVS conf)]]
     queryVs <- liftIO $ readTVarIO queryVsSTM
 
     -- query load of all possible segments
@@ -411,7 +411,7 @@ bootstrapQueryId nsSTM (bootstrapHost, bootstrapPort) targetID = do
       SockAddrInet6 _ _ bootstrapIP _ -> pure bootstrapIP
       _ -> throwError $ "Expected an IPv6 address, but got " <> show bootstrapAddr
     let possibleJoinIDs =
-            [ genNodeID bootstrapIP bootstrapHost (fromInteger v) | v <- [0..pred (
+            [ genNodeID bootstrapIP bootstrapHost v | v <- [0..pred (
             if confEnableKChoices nodeConf then confKChoicesMaxVS nodeConf else 1)]]
     tryQuery ns srcAddr nodeConf possibleJoinIDs
   where

src/Hash2Pub/FediChordTypes.hs

@@ -190,7 +190,7 @@ data RemoteNodeState = RemoteNodeState
     -- ^ port of the DHT itself
     , servicePort :: PortNumber
     -- ^ port of the service provided on top of the DHT
-    , vServerID   :: Integer
+    , vServerID   :: Word8
     -- ^ ID of this vserver
     }
     deriving (Show, Eq)
@@ -235,14 +235,14 @@ class NodeState a where
     getIpAddr :: a -> HostAddress6
     getDhtPort :: a -> PortNumber
     getServicePort :: a -> PortNumber
-    getVServerID :: a -> Integer
+    getVServerID :: a -> Word8
     -- setters for common properties
     setNid :: NodeID -> a -> a
     setDomain :: String -> a -> a
     setIpAddr :: HostAddress6 -> a -> a
     setDhtPort :: PortNumber -> a -> a
     setServicePort :: PortNumber -> a -> a
-    setVServerID :: Integer -> a -> a
+    setVServerID :: Word8 -> a -> a
     toRemoteNodeState :: a -> RemoteNodeState
 
 instance NodeState RemoteNodeState where
@@ -391,6 +391,11 @@ genNodeID :: HostAddress6       -- ^a node's IPv6 address
             -> NodeID           -- ^the generated @NodeID@
 genNodeID ip nodeDomain vs = NodeID . byteStringToUInteger $ genNodeIDBS ip nodeDomain vs
 
+
+isValidIdForNode :: Word8 -> RemoteNodeState -> HostAddress6 -> Bool
+isValidIdForNode numVs rns addr = getNid rns `elem` [genNodeID addr (getDomain rns) v | v <- [0..(numVs-1)] ]
+
+
 -- | generates a 256 bit long key identifier, represented as ByteString, for looking up its data on the DHT
 genKeyIDBS :: String            -- ^the key string
            -> BS.ByteString     -- ^the key ID represented as a @ByteString@
@@ -451,7 +456,7 @@ data FediChordConf = FediChordConf
     -- ^ fraction of capacity above which a node considers itself overloaded
     , confKChoicesUnderload         :: Double
     -- ^ fraction of capacity below which a node considers itself underloaded
-    , confKChoicesMaxVS             :: Integer
+    , confKChoicesMaxVS             :: Word8
     -- ^ upper limit of vserver index κ
     }
     deriving (Show, Eq)