define data types for DHT messaging

encoding and parsing functions have been adjusted accordingly

Hash2Pub/src/Hash2Pub/ASN1Coding.hs

@@ -24,6 +24,54 @@ data Action =
   | Ping
   deriving (Show, Eq, Enum)
 
+-- ToDo: probably move this to DHTProtocol as it is high-level
+
+data FediChordMessage = FediChordMessage {
+    messageType     :: MessageType
+  , requestID       :: Integer
+  , senderID        :: NodeID
+  , parts           :: Integer
+  , part            :: Integer
+  , action          :: Action
+  , payload         :: ActionPayload
+                        } deriving (Show, Eq)
+
+data MessageType = Request | Response deriving (Show, Eq, Enum)
+
+data ActionPayload = 
+    QueryIDRequestPayload {
+        queryTargetID   :: NodeID
+      , queryLBestNodes :: Integer
+                          }
+  | JoinRequestPayload {
+        joinNodeState   :: NodeState
+                       }
+  | LeaveRequestPayload {
+        leaveSuccessors     :: [NodeID]
+      , leavePredecessors   :: [NodeID]
+                        }
+  | StabiliseRequestPayload {
+        stabiliseNodeState  :: NodeState
+                            }
+  | PingRequestPayload
+  | QueryIDResponsePayload {
+        queryResult     :: QueryResponse
+                           }
+  | JoinResponsePayload {
+        joinSuccessors      :: [NodeID]
+      , joinPredecessors    :: [NodeID]
+      , joinCache           :: [CacheEntry]
+                        }
+  | LeaveResponsePayload
+  | StabiliseResponsePayload {
+        stabiliseSuccessors     :: [NodeID]
+      , stabilisePredecessors   :: [NodeID]
+                             }
+  | PingResponsePayload {
+        pingNodeStates  :: [NodeState]
+                        }
+    deriving (Show, Eq)
+
 -- ToDo: pagination so packets do not exceed maximum size
 -- probably should be taken care of by the callers of this, as the ASN.1
 -- encoding functions are layer-4 agnostic
@@ -51,33 +99,45 @@ encodeCacheEntry (NodeEntry _ ns timestamp) =
   , End Sequence]
 encodeCacheEntry _ = []
     
-encodeLeaveReceivePayload :: [ASN1]
+encodeLeaveResponsePayload :: [ASN1]
-encodeLeaveReceivePayload = [Null]
+encodeLeaveResponsePayload = [Null]
 
-encodeLeaveSendPayload :: [NodeID] -> [NodeID] -> [ASN1]
+encodeLeaveRequestPayload :: ActionPayload -> [ASN1]
-encodeLeaveSendPayload succ' pred' = 
+encodeLeaveRequestPayload payload@LeaveRequestPayload{} = 
     Start Sequence
   : Start Sequence
-  : map (IntVal . getNodeID) succ'
+  : map (IntVal . getNodeID) $ leaveSuccessors payload
   ++ [End Sequence
   , Start Sequence]
-  ++ map (IntVal . getNodeID) pred'
+  ++ map (IntVal . getNodeID) $ leavePredecessors payload
   ++ [End Sequence
-    , End Sequence]
+  , End Sequence]
 
--- currently StabiliseReceivePayload and LeaveSendPayload are equal
+-- currently StabiliseResponsePayload and LeaveRequestPayload are equal
-encodeStabiliseReceivePayload :: [NodeID] -> [NodeID] -> [ASN1]
+encodeStabiliseResponsePayload :: ActionPayload -> [ASN1]
-encodeStabiliseReceivePayload = encodeLeaveSendPayload
+encodeStabiliseResponsePayload payload@StabiliseResponsePayload{} = 
+    Start Sequence
+  : Start Sequence
+  : map (IntVal . getNodeID) $ stabiliseSuccessors payload
+  ++ [End Sequence
+  , Start Sequence]
+  ++ map (IntVal . getNodeID) $ stabilisePredecessors payload
+  ++ [End Sequence
+  , End Sequence]
 
-encodeStabiliseSendPayload :: NodeState -> [ASN1]
+encodeStabiliseRequestPayload :: ActionPayload -> [ASN1]
-encodeStabiliseSendPayload = encodeNodeState
+encodeStabiliseRequestPayload payload@StabiliseRequestPayload =
+    encodeNodeState $ stabiliseNodeState payload
 
 encodeQueryResult :: QueryResponse -> ASN1
 encodeQueryResult FOUND{} = Enumerated 0
 encodeQueryResult FORWARD{} = Enumerated 1
 
-encodeQueryIDReceivePayload :: QueryResponse -> [ASN1]
+encodeQueryIDResponsePayload :: ActionPayload -> [ASN1]
-encodeQueryIDReceivePayload resp = 
+encodeQueryIDResponsePayload payload@QueryIDResponsePayload{} = 
+  let
+    resp = queryResult payload
+  in
     Start Sequence
   : encodeQueryResult resp
   : case resp of
@@ -88,64 +148,74 @@ encodeQueryIDReceivePayload resp =
           ++ [End Sequence]
   ++ [End Sequence]
 
-encodeQueryIDSendPayload :: NodeID -> Integer -> [ASN1]
+encodeQueryIDRequestPayload :: ActionPayload -> [ASN1]
-encodeQueryIDSendPayload targetID lNodes = [
+encodeQueryIDRequestPayload payload@QueryIDResponsePayload = [
     Start Sequence
-  , IntVal . getNodeID $ targetID
+  , IntVal . getNodeID $ queryTargetID payload
-  , IntVal lNodes
+  , IntVal $ queryLBestNodes payload
   , End Sequence
                                            ]
 
--- | encodes the @JoinReceivePayload@ ASN.1 type
+-- | encodes the @JoinResponsePayload@ ASN.1 type
-encodeJoinReceivePayload :: [NodeID] -> [NodeID] -> [CacheEntry] -> [ASN1]
+encodeJoinResponsePayload :: ActionPayload -> [ASN1]
-encodeJoinReceivePayload succ' pred' ncache =
+encodeJoinResponsePayload payload@JoinResponsePayload =
     Start Sequence
   : Start Sequence
-  : map (IntVal . getNodeID) succ'
+  : map (IntVal . getNodeID) $ joinSuccessors payload
   ++ [End Sequence
   , Start Sequence]
-  ++ map (IntVal . getNodeID) pred'
+  ++ map (IntVal . getNodeID) $ joinPredecessors payload
   ++ [End Sequence
     , Start Sequence]
-  ++ concatMap encodeCacheEntry ncache
+  ++ concatMap encodeCacheEntry $ joinCache payload
   ++ [End Sequence
     , End Sequence]
 
-encodeJoinSendPayload :: NodeState -> [ASN1]
+encodeJoinRequestPayload :: ActionPayload -> [ASN1]
-encodeJoinSendPayload = encodeNodeState
+encodeJoinRequestPayload payload@JoinRequestPayload =
+    encodeNodeState $ joinNodeState payload
 
-encodePingSendPayload :: [ASN1]
+encodePingRequestPayload :: [ASN1]
-encodePingSendPayload = Null
+encodePingRequestPayload = Null
 
-encodePingReceivePayload :: [NodeState] -> [ASN1]
+encodePingResponsePayload :: ActionPayload -> [ASN1]
-encodePingReceivePayload nss =
+encodePingResponsePayload payload@PingResponsePayload =
     Start Sequence
-  : concatMap encodeNodeState nss
+  : concatMap encodeNodeState $ pingNodeStates payload
   ++ [End Sequence]
 
-encodeRequest :: Integer -> NodeID -> Integer -> Integer -> Action -> [ASN1] -> [ASN1]
+-- | Encode a 'FediChordMessage' as ASN.1.
-encodeRequest requestID senderID parts part action payload = [
+-- The 'ActionPayload' needs to be passed separately, already encoded as ASN.1,
-    Start Sequence
+-- to allow controlling message size by splitting the payload into multiple parts.
-  , Enumerated . fromIntegral . fromEnum $ action
+encodeMessage :: FediChordMessage   -- ^ the 'FediChordMessage to be encoded, the
-  , IntVal requestID
+                                    -- contained 'payload' is ignored
-  , IntVal . getNodeID $ senderID
+              -> [ASN1]             -- ^ the ASN.1 encoding of
-  , IntVal parts
+                                    -- the message's 'payload'
-  , IntVal part ]
+              -> [ASN1]
-  ++ payload
+encodeMessage
-
+    (FediChordMessage Request requestID senderID parts part action _)
-encodeResponse :: Integer -> NodeID -> Integer -> Integer -> Action -> [ASN1] -> [ASN1]
+    payload = [
-encodeResponse responseTo senderID parts part action payload = [
+        Start Sequence
-    Start Sequence
+      , Enumerated . fromIntegral . fromEnum $ action
-  , IntVal responseTo
+      , IntVal requestID
-  , IntVal . getNodeID $ senderID
+      , IntVal . getNodeID $ senderID
-  , IntVal parts
+      , IntVal parts
-  , IntVal part
+      , IntVal part ]
-  , Enumerated . fromIntegral . fromEnum $ action]
+      ++ payload
-  ++ payload
+encodeMessage
+    (FediChordMessage Response responseTo senderID parts part action _)
+    payload = [
+        Start Sequence
+      , IntVal responseTo
+      , IntVal . getNodeID $ senderID
+      , IntVal parts
+      , IntVal part
+      , Enumerated . fromIntegral . fromEnum $ action]
+      ++ payload
 
 -- ===== parser combinators =====
 
-parseMessage :: ParseASN1 () -- todo: change type
+parseMessage :: ParseASN1 FediChordMessage
 parseMessage = do
 -- request and response messages are distiguishable by their structure,
 -- see ASN.1 schema
@@ -154,7 +224,7 @@ parseMessage = do
       Enumerated a -> parseRequest . toEnum $ a
       IntVal i -> parseResponse i
 
-parseRequest :: Action -> ParseASN1 () -- todo: change type
+parseRequest :: Action -> ParseASN1 FediChordMessage
 parseRequest action = do
     requestID <- parseInteger
     senderID <- (fromInteger <$> parseInteger :: ParseASN1 NodeID)
@@ -170,7 +240,7 @@ parseRequest action = do
 
     return ()
 
-parseResponse :: Integer -> ParseASN1 () -- todo: change type
+parseResponse :: Integer -> ParseASN1 FediChordMessage
 parseResponse responseTo = do
     senderID <- (fromInteger <$> parseInteger :: ParseASN1 NodeID)
     parts <- parseInteger