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join request + large FediChord refactoring

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- implement sending of initial join request sending, response parsing
  and cache population (untested but compiles)
- refactor basic types and their functions into Hash2Pub.FediChordTypes
  to prevent import loops, leaving Hash2Pub.FediChord to contain the
  high level actions called from Main
This commit is contained in:
Trolli Schmittlauch 2020-05-25 22:00:22 +02:00
parent d5841d13fd
commit e3bfa26ddb
6 changed files with 607 additions and 467 deletions
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2
Hash2Pub.cabal
View file

@ -55,7 +55,7 @@ library
import: deps
-- Modules exported by the library.
exposed-modules: Hash2Pub.FediChord, Hash2Pub.DHTProtocol, Hash2Pub.ASN1Coding, Hash2Pub.ProtocolTypes
exposed-modules: Hash2Pub.FediChord, Hash2Pub.FediChordTypes, Hash2Pub.DHTProtocol, Hash2Pub.ASN1Coding, Hash2Pub.ProtocolTypes
-- Modules included in this library but not exported.
other-modules: Hash2Pub.Utils

2
src/Hash2Pub/ASN1Coding.hs
View file

@ -16,7 +16,7 @@ import qualified Data.Set as Set
import Data.Time.Clock.POSIX ()
import Safe
import Hash2Pub.FediChord
import Hash2Pub.FediChordTypes
import Hash2Pub.ProtocolTypes
import Hash2Pub.Utils

109
src/Hash2Pub/DHTProtocol.hs
View file

@ -14,6 +14,11 @@ module Hash2Pub.DHTProtocol
, maximumParts
, sendQueryIdMessage
, requestQueryID
, requestJoin
, queryIdLookupLoop
, resolve
, mkSendSocket
, mkServerSocket
)
where
@ -24,8 +29,11 @@ import Control.Concurrent.STM.TQueue
import Control.Monad (foldM, forM, forM_)
import qualified Data.ByteString as BS
import Data.Either (rights)
import Data.Foldable (foldl')
import Data.Foldable (foldl', foldr')
import Data.IORef
import Data.IP (IPv6, fromHostAddress6,
toHostAddress6)
import Data.List (sortBy)
import qualified Data.Map as Map
import Data.Maybe (fromJust, fromMaybe, mapMaybe,
maybe)
@ -39,15 +47,15 @@ import System.Random
import System.Timeout
import Hash2Pub.ASN1Coding
import Hash2Pub.FediChord (CacheEntry (..),
import Hash2Pub.FediChordTypes (CacheEntry (..),
LocalNodeState (..), NodeCache,
NodeID, NodeState (..),
RemoteNodeState (..),
cacheGetNodeStateUnvalidated,
cacheLookup, cacheLookupPred,
cacheLookupSucc, localCompare,
mkSendSocket, mkServerSocket,
setPredecessors, setSuccessors)
localCompare, setPredecessors,
setSuccessors)
import Hash2Pub.ProtocolTypes
import Debug.Trace (trace)
@ -134,25 +142,58 @@ markCacheEntryAsVerified timestamp = Map.adjust adjustFunc
-- ====== message send and receive operations ======
requestQueryID :: LocalNodeState -> NodeID -> IO RemoteNodeState
-- | send a join request and return the joined 'LocalNodeState' including neighbours
requestJoin :: NodeState a => a -- ^ currently responsible node to be contacted
-> LocalNodeState -- ^ joining NodeState
-> IO (Maybe LocalNodeState) -- ^ node after join with all its new information
requestJoin toJoinOn ownState = do
sock <- mkSendSocket (getDomain toJoinOn) (getDhtPort toJoinOn)
responses <- sendRequestTo 5000 3 (\rid -> Request rid (toRemoteNodeState ownState) 1 1 Join (Just JoinRequestPayload)) sock
joinedStateUnsorted <- foldM
(\nsAcc msg -> case payload msg of
Nothing -> pure nsAcc
Just msgPl -> do
-- add transfered cache entries to global NodeCache
queueAddEntries (joinCache msgPl) nsAcc
-- add received predecessors and successors
let
addPreds ns' = setPredecessors (foldr' (:) (predecessors ns') (joinPredecessors msgPl)) ns'
addSuccs ns' = setSuccessors (foldr' (:) (successors ns') (joinSuccessors msgPl)) ns'
pure $ addSuccs . addPreds $ nsAcc
)
-- reset predecessors and successors
(setPredecessors [] . setSuccessors [] $ ownState)
responses
if responses == Set.empty
then pure Nothing
-- sort successors and predecessors
else pure . Just . setSuccessors (sortBy localCompare $ successors joinedStateUnsorted) . setPredecessors (sortBy localCompare $ predecessors joinedStateUnsorted) $ joinedStateUnsorted
-- | Send a 'QueryID' 'Request' for getting the node that handles a certain key ID.
requestQueryID :: LocalNodeState -- ^ NodeState of the querying node
-> NodeID -- ^ target key ID to look up
-> IO RemoteNodeState -- ^ the node responsible for handling that key
-- 1. do a local lookup for the l closest nodes
-- 2. create l sockets
-- 3. send a message async concurrently to all l nodes
-- 4. collect the results, insert them into cache
-- 5. repeat until FOUND (problem: new entries not necessarily already in cache, explicitly compare with closer results)
-- TODO: deal with lookup failures
requestQueryID ns targetID = do
firstCacheSnapshot <- readIORef . nodeCacheRef $ ns
lookupLoop firstCacheSnapshot
where
lookupLoop :: NodeCache -> IO RemoteNodeState
lookupLoop cacheSnapshot = do
queryIdLookupLoop firstCacheSnapshot ns targetID
-- | like 'requestQueryID, but allows passing of a custom cache, e.g. for joining
queryIdLookupLoop :: NodeCache -> LocalNodeState -> NodeID -> IO RemoteNodeState
queryIdLookupLoop cacheSnapshot ns targetID = do
let localResult = queryLocalCache ns cacheSnapshot (lNumBestNodes ns) targetID
-- FOUND can only be returned if targetID is owned by local node
case localResult of
FOUND thisNode -> pure thisNode
FORWARD nodeSet -> do
-- create connected sockets to all query targets
sockets <- mapM (\resultNode -> mkSendSocket (domain resultNode) (dhtPort resultNode)) $ remoteNode <$> Set.toList nodeSet
sockets <- mapM (\resultNode -> mkSendSocket (getDomain resultNode) (getDhtPort resultNode)) $ remoteNode <$> Set.toList nodeSet
-- ToDo: make attempts and timeout configurable
queryThreads <- mapM (async . sendQueryIdMessage targetID ns) sockets
-- ToDo: process results immediately instead of waiting for the last one to finish, see https://stackoverflow.com/a/38815224/9198613
@ -179,7 +220,7 @@ requestQueryID ns targetID = do
_ -> Nothing
) $ responses
-- if no FOUND, recursively call lookup again
maybe (lookupLoop newLCache) pure foundResp
maybe (queryIdLookupLoop newLCache ns targetID) pure foundResp
sendQueryIdMessage :: NodeID -- ^ target key ID to look up
@ -208,8 +249,7 @@ sendRequestTo timeoutMillis numAttempts msgIncomplete sock = do
attempts numAttempts . timeout timeoutMillis $ sendAndAck responseQ sock requests
-- after timeout, check received responses, delete them from unacked message set/ map and rerun senAndAck with that if necessary.
recvdParts <- atomically $ flushTBQueue responseQ
-- PLACEHOLDER
pure Set.empty
pure $ Set.fromList recvdParts
where
-- state reingeben: state = noch nicht geackte messages, result = responses
sendAndAck :: TBQueue FediChordMessage -- ^ the queue for putting in the received responses
@ -242,6 +282,14 @@ sendRequestTo timeoutMillis numAttempts msgIncomplete sock = do
else recvLoop responseQueue newRemaining receivedPartNums
-- | enqueue a list of RemoteCacheEntries to be added to the global NodeCache
queueAddEntries :: [RemoteCacheEntry]
-> LocalNodeState
-> IO ()
queueAddEntries entries ns = do
now <- getPOSIXTime
forM_ entries $ \entry -> atomically $ writeTQueue (cacheWriteQueue ns) $ addCacheEntryPure now entry
-- | retry an IO action at most *i* times until it delivers a result
attempts :: Int -- ^ number of retries *i*
-> IO (Maybe a) -- ^ action to retry
@ -252,3 +300,38 @@ attempts i action = do
case actionResult of
Nothing -> attempts (i-1) action
Just res -> pure $ Just res
-- ====== network socket operations ======
-- | resolve a specified host and return the 'AddrInfo' for it.
-- If no hostname or IP is specified, the 'AddrInfo' can be used to bind to all
-- addresses;
-- if no port is specified an arbitrary free port is selected.
resolve :: Maybe String -- ^ hostname or IP address to be resolved
-> Maybe PortNumber -- ^ port number of either local bind or remote
-> IO AddrInfo
resolve host port = let
hints = defaultHints { addrFamily = AF_INET6, addrSocketType = Datagram
, addrFlags = [AI_PASSIVE] }
in
head <$> getAddrInfo (Just hints) host (show <$> port)
-- | create an unconnected UDP Datagram 'Socket' bound to the specified address
mkServerSocket :: HostAddress6 -> PortNumber -> IO Socket
mkServerSocket ip port = do
sockAddr <- addrAddress <$> resolve (Just $ show . fromHostAddress6 $ ip) (Just port)
sock <- socket AF_INET6 Datagram defaultProtocol
setSocketOption sock IPv6Only 1
bind sock sockAddr
pure sock
-- | create a UDP datagram socket, connected to a destination.
-- The socket gets an arbitrary free local port assigned.
mkSendSocket :: String -- ^ destination hostname or IP
-> PortNumber -- ^ destination port
-> IO Socket -- ^ a socket with an arbitrary source port
mkSendSocket dest destPort = do
destAddr <- addrAddress <$> resolve (Just dest) (Just destPort)
sendSock <- socket AF_INET6 Datagram defaultProtocol
setSocketOption sendSock IPv6Only 1
pure sendSock

455
src/Hash2Pub/FediChord.hs
View file

@ -1,6 +1,5 @@
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : FediChord
@ -46,8 +45,10 @@ module Hash2Pub.FediChord (
) where
import Control.Exception
import Data.Foldable (foldr')
import qualified Data.Map.Strict as Map
import Data.Maybe (fromMaybe, isJust, mapMaybe)
import qualified Data.Set as Set
import Data.Time.Clock.POSIX
import Network.Socket
@ -66,379 +67,12 @@ import Data.Typeable (Typeable (..), typeOf)
import Data.Word
import qualified Network.ByteOrder as NetworkBytes
import Hash2Pub.DHTProtocol
import Hash2Pub.FediChordTypes
import Hash2Pub.Utils
import Debug.Trace (trace)
-- define protocol constants
-- | static definition of ID length in bits
idBits :: Integer
idBits = 256
-- |NodeIDs are Integers wrapped in a newtype, to be able to redefine
-- their instance behaviour
--
-- for being able to check value bounds, the constructor should not be used directly
-- and new values are created via @toNodeID@ (newtype constructors cannot be hidden)
newtype NodeID = NodeID { getNodeID :: Integer } deriving stock (Show, Eq) deriving newtype Enum
-- |smart data constructor for NodeID that throws a runtime exception for out-of-bounds values.
-- When needing a runtime-safe constructor with drawbacks, try @fromInteger@
toNodeID :: Integer -> NodeID
toNodeID i = assert (i >= getNodeID minBound && i <= getNodeID maxBound) $ NodeID i
-- |NodeIDs are bounded by the value range of an unsigned Integer of length 'idBits'
instance Bounded NodeID where
minBound = NodeID 0
maxBound = NodeID (2^idBits - 1)
-- |calculations with NodeIDs are modular arithmetic operations
instance Num NodeID where
a + b = NodeID $ (getNodeID a + getNodeID b) `mod` (getNodeID maxBound + 1)
a * b = NodeID $ (getNodeID a * getNodeID b) `mod` (getNodeID maxBound + 1)
a - b = NodeID $ (getNodeID a - getNodeID b) `mod` (getNodeID maxBound + 1)
-- |safe constructor for NodeID values with the drawback, that out-of-bound values are wrapped around
-- with modulo to fit in the allowed value space. For runtime checking, look at @toNodeID@.
fromInteger i = NodeID $ i `mod` (getNodeID maxBound + 1)
signum = NodeID . signum . getNodeID
abs = NodeID . abs . getNodeID -- ToDo: make sure that at creation time only IDs within the range are used
-- | use normal strict monotonic ordering of integers, realising the ring structure
-- is done in the @NodeCache@ implementation
instance Ord NodeID where
a `compare` b = getNodeID a `compare` getNodeID b
-- | local comparison of 2 node IDs, only relevant for determining a successor or predecessor on caches with just 2 nodes
localCompare :: NodeID -> NodeID -> Ordering
a `localCompare` b
| getNodeID a == getNodeID b = EQ
| wayForwards > wayBackwards = GT
| otherwise = LT
where
wayForwards = getNodeID (b - a)
wayBackwards = getNodeID (a - b)
-- | represents a node and all its important state
data RemoteNodeState = RemoteNodeState
{ nid :: NodeID
, domain :: String
-- ^ full public domain name the node is reachable under
, ipAddr :: HostAddress6
-- the node's public IPv6 address
, dhtPort :: PortNumber
-- ^ port of the DHT itself
, servicePort :: PortNumber
-- ^ port of the service provided on top of the DHT
, vServerID :: Integer
-- ^ ID of this vserver
}
deriving (Show, Eq)
-- | represents a node and encapsulates all data and parameters that are not present for remote nodes
data LocalNodeState = LocalNodeState
{ nodeState :: RemoteNodeState
-- ^ represents common data present both in remote and local node representations
, nodeCacheRef :: IORef NodeCache
-- ^ EpiChord node cache with expiry times for nodes
, cacheWriteQueue :: TQueue (NodeCache -> NodeCache)
-- ^ cache updates are not written directly to the 'nodeCache' but queued and
, successors :: [NodeID] -- could be a set instead as these are ordered as well
-- ^ successor nodes in ascending order by distance
, predecessors :: [NodeID]
-- ^ predecessor nodes in ascending order by distance
, kNeighbours :: Int
-- ^ desired length of predecessor and successor list
, lNumBestNodes :: Int
-- ^ number of best next hops to provide
, pNumParallelQueries :: Int
-- ^ number of parallel sent queries
, jEntriesPerSlice :: Int
-- ^ number of desired entries per cache slice
}
deriving (Show, Eq)
-- | class for various NodeState representations, providing
-- getters and setters for common values
class NodeState a where
-- getters for common properties
getNid :: a -> NodeID
getDomain :: a -> String
getIpAddr :: a -> HostAddress6
getDhtPort :: a -> PortNumber
getServicePort :: a -> PortNumber
getVServerID :: a -> Integer
-- 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
toRemoteNodeState :: a -> RemoteNodeState
instance NodeState RemoteNodeState where
getNid = nid
getDomain = domain
getIpAddr = ipAddr
getDhtPort = dhtPort
getServicePort = servicePort
getVServerID = vServerID
setNid nid' ns = ns {nid = nid'}
setDomain domain' ns = ns {domain = domain'}
setIpAddr ipAddr' ns = ns {ipAddr = ipAddr'}
setDhtPort dhtPort' ns = ns {dhtPort = dhtPort'}
setServicePort servicePort' ns = ns {servicePort = servicePort'}
setVServerID vServerID' ns = ns {vServerID = vServerID'}
toRemoteNodeState = id
-- | helper function for setting values on the 'RemoteNodeState' contained in the 'LocalNodeState'
propagateNodeStateSet_ :: (RemoteNodeState -> RemoteNodeState) -> LocalNodeState -> LocalNodeState
propagateNodeStateSet_ func ns = let
newNs = func $ nodeState ns
in
ns {nodeState = newNs}
instance NodeState LocalNodeState where
getNid = getNid . nodeState
getDomain = getDomain . nodeState
getIpAddr = getIpAddr . nodeState
getDhtPort = getDhtPort . nodeState
getServicePort = getServicePort . nodeState
getVServerID = getVServerID . nodeState
setNid nid' = propagateNodeStateSet_ $ setNid nid'
setDomain domain' = propagateNodeStateSet_ $ setDomain domain'
setIpAddr ipAddr' = propagateNodeStateSet_ $ setIpAddr ipAddr'
setDhtPort dhtPort' = propagateNodeStateSet_ $ setDhtPort dhtPort'
setServicePort servicePort' = propagateNodeStateSet_ $ setServicePort servicePort'
setVServerID vServerID' = propagateNodeStateSet_ $ setVServerID vServerID'
toRemoteNodeState = nodeState
-- | defining Show instances to be able to print NodeState for debug purposes
instance Typeable a => Show (IORef a) where
show x = show (typeOf x)
instance Typeable a => Show (TQueue a) where
show x = show (typeOf x)
-- | convenience function that updates the successors of a 'LocalNodeState'
setSuccessors :: [NodeID] -> LocalNodeState -> LocalNodeState
setSuccessors succ' ns = ns {successors = succ'}
-- | convenience function that updates the predecessors of a 'LocalNodeState'
setPredecessors :: [NodeID] -> LocalNodeState -> LocalNodeState
setPredecessors pred' ns = ns {predecessors = pred'}
type NodeCache = Map.Map NodeID CacheEntry
-- | An entry of the 'nodeCache' can hold 2 different kinds of data.
-- Type variable @a@ should be of type class 'NodeState', but I do not want to use GADTs here.
data CacheEntry = NodeEntry Bool RemoteNodeState POSIXTime
| ProxyEntry (NodeID, ProxyDirection) (Maybe CacheEntry)
deriving (Show, Eq)
-- | as a compromise, only NodeEntry components are ordered by their NodeID
-- while ProxyEntry components should never be tried to be ordered.
instance Ord CacheEntry where
a `compare` b = compare (extractID a) (extractID b)
where
extractID (NodeEntry _ eState _) = getNid eState
extractID (ProxyEntry _ _) = error "proxy entries should never appear outside of the NodeCache"
data ProxyDirection = Backwards
| Forwards
deriving (Show, Eq)
instance Enum ProxyDirection where
toEnum (-1) = Backwards
toEnum 1 = Forwards
toEnum _ = error "no such ProxyDirection"
fromEnum Backwards = - 1
fromEnum Forwards = 1
--- useful function for getting entries for a full cache transfer
cacheEntries :: NodeCache -> [CacheEntry]
cacheEntries ncache = mapMaybe extractNodeEntries $ Map.elems ncache
where
extractNodeEntries (ProxyEntry _ possibleEntry) = possibleEntry
-- | An empty @NodeCache@ needs to be initialised with 2 proxy entries,
-- linking the modular name space together by connecting @minBound@ and @maxBound@
initCache :: NodeCache
initCache = Map.fromList $ proxyEntry <$> [(maxBound, (minBound, Forwards)), (minBound, (maxBound, Backwards))]
where
proxyEntry (from,to) = (from, ProxyEntry to Nothing)
-- | Maybe returns the cache entry stored at given key
cacheLookup :: NodeID -- ^lookup key
-> NodeCache -- ^lookup cache
-> Maybe CacheEntry
cacheLookup key cache = case Map.lookup key cache of
Just (ProxyEntry _ result) -> result
res -> res
-- | a wrapper around lookup functions, making the lookup redirectable by a @ProxyEntry@
-- to simulate a modular ring
lookupWrapper :: (NodeID -> NodeCache -> Maybe (NodeID, CacheEntry)) -> (NodeID -> NodeCache -> Maybe (NodeID, CacheEntry)) -> ProxyDirection -> NodeID -> NodeCache -> Maybe CacheEntry
lookupWrapper f fRepeat direction key cache =
case f key cache of
-- the proxy entry found holds a
Just (_, ProxyEntry _ (Just entry@NodeEntry{})) -> Just entry
-- proxy entry holds another proxy entry, this should not happen
Just (_, ProxyEntry _ (Just (ProxyEntry _ _))) -> Nothing
-- proxy entry without own entry is a pointer on where to continue
-- if lookup direction is the same as pointer direction: follow pointer
Just (foundKey, ProxyEntry (pointerID, pointerDirection) Nothing) ->
let newKey = if pointerDirection == direction
then pointerID
else foundKey + (fromInteger . toInteger . fromEnum $ direction)
in if cacheNotEmpty cache
then lookupWrapper fRepeat fRepeat direction newKey cache
else Nothing
-- normal entries are returned
Just (_, entry@NodeEntry{}) -> Just entry
Nothing -> Nothing
where
cacheNotEmpty :: NodeCache -> Bool
cacheNotEmpty cache' = (Map.size cache' > 2) -- there are more than the 2 ProxyEntries
|| isJust ( cacheLookup minBound cache') -- or one of the ProxyEntries holds a node
|| isJust (cacheLookup maxBound cache')
-- | find the successor node to a given key on a modular EpiChord ring cache.
-- Note: The EpiChord definition of "successor" includes the node at the key itself,
-- if existing.
cacheLookupSucc :: NodeID -- ^lookup key
-> NodeCache -- ^ring cache
-> Maybe CacheEntry
cacheLookupSucc = lookupWrapper Map.lookupGE Map.lookupGE Forwards
-- | find the predecessor node to a given key on a modular EpiChord ring cache.
cacheLookupPred :: NodeID -- ^lookup key
-> NodeCache -- ^ring cache
-> Maybe CacheEntry
cacheLookupPred = lookupWrapper Map.lookupLT Map.lookupLE Backwards
-- clean up cache entries: once now - entry > maxAge
-- transfer difference now - entry to other node
-- | return the @NodeState@ data from a cache entry without checking its validation status
cacheGetNodeStateUnvalidated :: CacheEntry -> RemoteNodeState
cacheGetNodeStateUnvalidated (NodeEntry _ nState _) = nState
cacheGetNodeStateUnvalidated (ProxyEntry _ (Just entry)) = cacheGetNodeStateUnvalidated entry
cacheGetNodeStateUnvalidated _ = error "trying to pure empty node state, please report a bug"
-- | converts a 'HostAddress6' IP address to a big-endian strict ByteString
ipAddrAsBS :: HostAddress6 -> BS.ByteString
ipAddrAsBS (a, b, c, d) = mconcat $ fmap NetworkBytes.bytestring32 [a, b, c, d]
-- | converts a ByteString in big endian order to an IPv6 address 'HostAddress6'
bsAsIpAddr :: BS.ByteString -> HostAddress6
bsAsIpAddr bytes = (a,b,c,d)
where
a:b:c:d:_ = fmap NetworkBytes.word32 . chunkBytes 4 $ bytes
-- | generates a 256 bit long NodeID using SHAKE128, represented as ByteString
genNodeIDBS :: HostAddress6 -- ^a node's IPv6 address
-> String -- ^a node's 1st and 2nd level domain name
-> Word8 -- ^the used vserver ID
-> BS.ByteString -- ^the NodeID as a 256bit ByteString big-endian unsigned integer
genNodeIDBS ip nodeDomain vserver =
hashIpaddrUpper `BS.append` hashID nodeDomain' `BS.append` hashIpaddLower
where
vsBS = BS.pack [vserver] -- attention: only works for vserver IDs up to 255
ipaddrNet = BS.take 8 (ipAddrAsBS ip) `BS.append` vsBS
nodeDomain' = BSU.fromString nodeDomain `BS.append` vsBS
hashID bstr = BS.pack . BA.unpack $ (hash bstr :: Digest (SHAKE128 128))
(hashIpaddrUpper, hashIpaddLower) = BS.splitAt 64 $ hashID ipaddrNet
-- | generates a 256 bit long @NodeID@ using SHAKE128
genNodeID :: HostAddress6 -- ^a node's IPv6 address
-> String -- ^a node's 1st and 2nd level domain name
-> Word8 -- ^the used vserver ID
-> NodeID -- ^the generated @NodeID@
genNodeID ip nodeDomain vs = NodeID . byteStringToUInteger $ genNodeIDBS ip nodeDomain vs
-- | 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@
genKeyIDBS key = BS.pack . BA.unpack $ (hash (BSU.fromString key) :: Digest SHA3_256)
-- | generates a 256 bit long key identifier for looking up its data on the DHT
genKeyID :: String -- ^the key string
-> NodeID -- ^the key ID
genKeyID = NodeID . byteStringToUInteger . genKeyIDBS
-- | parses the bit pattern of a ByteString as an unsigned Integer in Big Endian order
-- by iterating it byte-wise from the back and shifting the byte values according to their offset
byteStringToUInteger :: BS.ByteString -> Integer
byteStringToUInteger bs = sum $ parsedBytes 0 bs
where
parsedBytes :: Integer -> BS.ByteString -> [ Integer ]
parsedBytes offset uintBs = case BS.unsnoc uintBs of
Nothing -> []
Just (bs', w) -> parseWithOffset offset w : parsedBytes (offset+1) bs'
parseWithOffset :: Integer -> Word8 -> Integer
parseWithOffset 0 word = toInteger word -- a shift of 0 is always 0
parseWithOffset offset word = toInteger word * 2^(8 * offset)
-- TODO: complete rewrite
-- |checks wether the cache entries fulfill the logarithmic EpiChord invariant
-- of having j entries per slice, and creates a list of necessary lookup actions.
-- Should be invoked periodically.
--checkCacheSlices :: NodeState -> IO [()]
--checkCacheSlices state = case getNodeCache state of
-- -- don't do anything on nodes without a cache
-- Nothing -> pure [()]
-- Just cache' -> checkSlice jEntries (nid state) startBound lastSucc =<< readIORef cache'
-- -- TODO: do the same for predecessors
-- where
-- jEntries = fromMaybe 0 $ getInternals_ jEntriesPerSlice state
-- lastSucc = last <$> maybeEmpty (fromMaybe [] $ getSuccessors state)
-- startBound = NodeID 2^(255::Integer) + nid state
-- checkSlice :: Int -> NodeID -> NodeID -> Maybe NodeID -> NodeCache -> [IO ()]
-- checkSlice _ _ _ Nothing _ = []
-- checkSlice j ownID upperBound (Just lastSuccNode) cache
-- | upperBound < lastSuccNode = []
-- | otherwise =
-- -- continuously half the DHT namespace, take the upper part as a slice,
-- -- check for existing entries in that slice and create a lookup action
-- -- and recursively do this on the lower half.
-- -- recursion edge case: all successors/ predecessors need to be in the
-- -- first slice.
-- let
-- diff = getNodeID $ upperBound - ownID
-- lowerBound = ownID + NodeID (diff `div` 2)
-- in
-- -- TODO: replace empty IO actions with actual lookups to middle of slice
-- -- TODO: validate ID before adding to cache
-- case Map.lookupLT upperBound cache of
-- Nothing -> pure () : checkSlice j ownID lowerBound (Just lastSuccNode) cache
-- Just (matchID, _) ->
-- if
-- matchID <= lowerBound then pure () : checkSlice j ownID lowerBound (Just lastSuccNode) cache
-- else
-- checkSlice j ownID lowerBound (Just lastSuccNode) cache
-- Todo: DHT backend can learn potential initial bootstrapping points through the instances mentioned in the received AP-relay messages
-- persist them on disk so they can be used for all following bootstraps
-- | configuration values used for initialising the FediChord DHT
data FediChordConf = FediChordConf
{ confDomain :: String
, confIP :: HostAddress6
, confDhtPort :: Int
}
deriving (Show, Eq)
-- | initialise data structures, compute own IDs and bind to listening socket
-- ToDo: load persisted state, thus this function already operates in IO
fediChordInit :: FediChordConf -> IO (Socket, LocalNodeState)
@ -475,16 +109,42 @@ nodeStateInit conf = do
}
pure initialState
--fediChordJoin :: LocalNodeState -- ^ the local 'NodeState'
-- -> (String, PortNumber) -- ^ domain and port of a bootstrapping node
-- -> Socket -- ^ socket used for sending and receiving the join message
-- -> IO Either String NodeState -- ^ the joined 'NodeState' after a successful
-- -- join, otherwise an error message
--fediChordJoin ns (joinHost, joinPort) sock = do
-- -- 1. get routed to destination until FOUND
-- -- 2. then send a join to the currently responsible node
-- -- ToDo: implement cache management, as already all received replies should be stored in cache
--
fediChordJoin :: LocalNodeState -- ^ the local 'NodeState'
-> (String, PortNumber) -- ^ domain and port of a bootstrapping node
-> IO (Either String LocalNodeState) -- ^ the joined 'NodeState' after a
-- successful join, otherwise an error message
fediChordJoin ns (joinHost, joinPort) = do
-- can be invoked multiple times with all known bootstrapping nodes until successfully joined
sock <- mkSendSocket joinHost joinPort
-- 1. get routed to placement of own ID until FOUND:
-- Initialise an empty cache only with the responses from a bootstrapping node
bootstrapResponse <- sendQueryIdMessage (getNid ns) ns sock
if bootstrapResponse == Set.empty
then pure . Left $ "Bootstrapping node " <> show joinHost <> " gave no response."
else do
now <- getPOSIXTime
-- create new cache with all returned node responses
let bootstrapCache =
-- traverse response parts
foldr' (\resp cacheAcc -> case queryResult <$> payload resp of
Nothing -> cacheAcc
Just (FOUND result1) -> addCacheEntryPure now (RemoteCacheEntry result1 now) cacheAcc
Just (FORWARD resultset) -> foldr' (addCacheEntryPure now) cacheAcc resultset
)
initCache bootstrapResponse
-- get routed to the currently responsible node, based on the response
-- from the bootstrapping node
currentlyResponsible <- queryIdLookupLoop bootstrapCache ns $ getNid ns
-- do actual join
joinResult <- requestJoin currentlyResponsible ns
case joinResult of
Nothing -> pure . Left $ "Error joining on " <> show currentlyResponsible
Just joinedNS -> pure . Right $ joinedNS
-- 2. then send a join to the currently responsible node
-- after successful join, finally add own node to the cache
-- | cache updater thread that waits for incoming NodeCache update instructions on
-- the node's cacheWriteQueue and then modifies the NodeCache as the single writer.
@ -497,38 +157,3 @@ cacheWriter ns = do
refModifier :: NodeCache -> (NodeCache, ())
refModifier nc = (f nc, ())
atomicModifyIORef' (nodeCacheRef ns) refModifier
-- ====== network socket operations ======
-- | resolve a specified host and return the 'AddrInfo' for it.
-- If no hostname or IP is specified, the 'AddrInfo' can be used to bind to all
-- addresses;
-- if no port is specified an arbitrary free port is selected.
resolve :: Maybe String -- ^ hostname or IP address to be resolved
-> Maybe PortNumber -- ^ port number of either local bind or remote
-> IO AddrInfo
resolve host port = let
hints = defaultHints { addrFamily = AF_INET6, addrSocketType = Datagram
, addrFlags = [AI_PASSIVE] }
in
head <$> getAddrInfo (Just hints) host (show <$> port)
-- | create an unconnected UDP Datagram 'Socket' bound to the specified address
mkServerSocket :: HostAddress6 -> PortNumber -> IO Socket
mkServerSocket ip port = do
sockAddr <- addrAddress <$> resolve (Just $ show . fromHostAddress6 $ ip) (Just port)
sock <- socket AF_INET6 Datagram defaultProtocol
setSocketOption sock IPv6Only 1
bind sock sockAddr
pure sock
-- | create a UDP datagram socket, connected to a destination.
-- The socket gets an arbitrary free local port assigned.
mkSendSocket :: String -- ^ destination hostname or IP
-> PortNumber -- ^ destination port
-> IO Socket -- ^ a socket with an arbitrary source port
mkSendSocket dest destPort = do
destAddr <- addrAddress <$> resolve (Just dest) (Just destPort)
sendSock <- socket AF_INET6 Datagram defaultProtocol
setSocketOption sendSock IPv6Only 1
pure sendSock

428
src/Hash2Pub/FediChordTypes.hs Normal file
View file

@ -0,0 +1,428 @@
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedStrings #-}
module Hash2Pub.FediChordTypes (
NodeID -- abstract, but newtype constructors cannot be hidden
, getNodeID
, toNodeID
, NodeState (..)
, LocalNodeState (..)
, RemoteNodeState (..)
, setSuccessors
, setPredecessors
, NodeCache
, CacheEntry(..)
, cacheGetNodeStateUnvalidated
, initCache
, cacheLookup
, cacheLookupSucc
, cacheLookupPred
, localCompare
, genNodeID
, genNodeIDBS
, genKeyID
, genKeyIDBS
, byteStringToUInteger
, ipAddrAsBS
, bsAsIpAddr
, FediChordConf(..)
) where
import Control.Exception
import qualified Data.Map.Strict as Map
import Data.Maybe (fromMaybe, isJust, mapMaybe)
import qualified Data.Set as Set
import Data.Time.Clock.POSIX
import Network.Socket
-- for hashing and ID conversion
import Control.Concurrent.STM
import Control.Concurrent.STM.TQueue
import Control.Monad (forever)
import Crypto.Hash
import qualified Data.ByteArray as BA
import qualified Data.ByteString as BS
import qualified Data.ByteString.UTF8 as BSU
import Data.IORef
import Data.IP (IPv6, fromHostAddress6,
toHostAddress6)
import Data.Typeable (Typeable (..), typeOf)
import Data.Word
import qualified Network.ByteOrder as NetworkBytes
import Hash2Pub.Utils
-- define protocol constants
-- | static definition of ID length in bits
idBits :: Integer
idBits = 256
-- |NodeIDs are Integers wrapped in a newtype, to be able to redefine
-- their instance behaviour
--
-- for being able to check value bounds, the constructor should not be used directly
-- and new values are created via @toNodeID@ (newtype constructors cannot be hidden)
newtype NodeID = NodeID { getNodeID :: Integer } deriving stock (Show, Eq) deriving newtype Enum
-- |smart data constructor for NodeID that throws a runtime exception for out-of-bounds values.
-- When needing a runtime-safe constructor with drawbacks, try @fromInteger@
toNodeID :: Integer -> NodeID
toNodeID i = assert (i >= getNodeID minBound && i <= getNodeID maxBound) $ NodeID i
-- |NodeIDs are bounded by the value range of an unsigned Integer of length 'idBits'
instance Bounded NodeID where
minBound = NodeID 0
maxBound = NodeID (2^idBits - 1)
-- |calculations with NodeIDs are modular arithmetic operations
instance Num NodeID where
a + b = NodeID $ (getNodeID a + getNodeID b) `mod` (getNodeID maxBound + 1)
a * b = NodeID $ (getNodeID a * getNodeID b) `mod` (getNodeID maxBound + 1)
a - b = NodeID $ (getNodeID a - getNodeID b) `mod` (getNodeID maxBound + 1)
-- |safe constructor for NodeID values with the drawback, that out-of-bound values are wrapped around
-- with modulo to fit in the allowed value space. For runtime checking, look at @toNodeID@.
fromInteger i = NodeID $ i `mod` (getNodeID maxBound + 1)
signum = NodeID . signum . getNodeID
abs = NodeID . abs . getNodeID -- ToDo: make sure that at creation time only IDs within the range are used
-- | use normal strict monotonic ordering of integers, realising the ring structure
-- is done in the @NodeCache@ implementation
instance Ord NodeID where
a `compare` b = getNodeID a `compare` getNodeID b
-- | local comparison of 2 node IDs, only relevant for determining a successor or predecessor on caches with just 2 nodes
localCompare :: NodeID -> NodeID -> Ordering
a `localCompare` b
| getNodeID a == getNodeID b = EQ
| wayForwards > wayBackwards = GT
| otherwise = LT
where
wayForwards = getNodeID (b - a)
wayBackwards = getNodeID (a - b)
-- | represents a node and all its important state
data RemoteNodeState = RemoteNodeState
{ nid :: NodeID
, domain :: String
-- ^ full public domain name the node is reachable under
, ipAddr :: HostAddress6
-- the node's public IPv6 address
, dhtPort :: PortNumber
-- ^ port of the DHT itself
, servicePort :: PortNumber
-- ^ port of the service provided on top of the DHT
, vServerID :: Integer
-- ^ ID of this vserver
}
deriving (Show, Eq)
-- | represents a node and encapsulates all data and parameters that are not present for remote nodes
data LocalNodeState = LocalNodeState
{ nodeState :: RemoteNodeState
-- ^ represents common data present both in remote and local node representations
, nodeCacheRef :: IORef NodeCache
-- ^ EpiChord node cache with expiry times for nodes
, cacheWriteQueue :: TQueue (NodeCache -> NodeCache)
-- ^ cache updates are not written directly to the 'nodeCache' but queued and
, successors :: [NodeID] -- could be a set instead as these are ordered as well
-- ^ successor nodes in ascending order by distance
, predecessors :: [NodeID]
-- ^ predecessor nodes in ascending order by distance
, kNeighbours :: Int
-- ^ desired length of predecessor and successor list
, lNumBestNodes :: Int
-- ^ number of best next hops to provide
, pNumParallelQueries :: Int
-- ^ number of parallel sent queries
, jEntriesPerSlice :: Int
-- ^ number of desired entries per cache slice
}
deriving (Show, Eq)
-- | class for various NodeState representations, providing
-- getters and setters for common values
class NodeState a where
-- getters for common properties
getNid :: a -> NodeID
getDomain :: a -> String
getIpAddr :: a -> HostAddress6
getDhtPort :: a -> PortNumber
getServicePort :: a -> PortNumber
getVServerID :: a -> Integer
-- 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
toRemoteNodeState :: a -> RemoteNodeState
instance NodeState RemoteNodeState where
getNid = nid
getDomain = domain
getIpAddr = ipAddr
getDhtPort = dhtPort
getServicePort = servicePort
getVServerID = vServerID
setNid nid' ns = ns {nid = nid'}
setDomain domain' ns = ns {domain = domain'}
setIpAddr ipAddr' ns = ns {ipAddr = ipAddr'}
setDhtPort dhtPort' ns = ns {dhtPort = dhtPort'}
setServicePort servicePort' ns = ns {servicePort = servicePort'}
setVServerID vServerID' ns = ns {vServerID = vServerID'}
toRemoteNodeState = id
-- | helper function for setting values on the 'RemoteNodeState' contained in the 'LocalNodeState'
propagateNodeStateSet_ :: (RemoteNodeState -> RemoteNodeState) -> LocalNodeState -> LocalNodeState
propagateNodeStateSet_ func ns = let
newNs = func $ nodeState ns
in
ns {nodeState = newNs}
instance NodeState LocalNodeState where
getNid = getNid . nodeState
getDomain = getDomain . nodeState
getIpAddr = getIpAddr . nodeState
getDhtPort = getDhtPort . nodeState
getServicePort = getServicePort . nodeState
getVServerID = getVServerID . nodeState
setNid nid' = propagateNodeStateSet_ $ setNid nid'
setDomain domain' = propagateNodeStateSet_ $ setDomain domain'
setIpAddr ipAddr' = propagateNodeStateSet_ $ setIpAddr ipAddr'
setDhtPort dhtPort' = propagateNodeStateSet_ $ setDhtPort dhtPort'
setServicePort servicePort' = propagateNodeStateSet_ $ setServicePort servicePort'
setVServerID vServerID' = propagateNodeStateSet_ $ setVServerID vServerID'
toRemoteNodeState = nodeState
-- | defining Show instances to be able to print NodeState for debug purposes
instance Typeable a => Show (IORef a) where
show x = show (typeOf x)
instance Typeable a => Show (TQueue a) where
show x = show (typeOf x)
-- | convenience function that updates the successors of a 'LocalNodeState'
setSuccessors :: [NodeID] -> LocalNodeState -> LocalNodeState
setSuccessors succ' ns = ns {successors = succ'}
-- | convenience function that updates the predecessors of a 'LocalNodeState'
setPredecessors :: [NodeID] -> LocalNodeState -> LocalNodeState
setPredecessors pred' ns = ns {predecessors = pred'}
type NodeCache = Map.Map NodeID CacheEntry
-- | An entry of the 'nodeCache' can hold 2 different kinds of data.
-- Type variable @a@ should be of type class 'NodeState', but I do not want to use GADTs here.
data CacheEntry = NodeEntry Bool RemoteNodeState POSIXTime
| ProxyEntry (NodeID, ProxyDirection) (Maybe CacheEntry)
deriving (Show, Eq)
-- | as a compromise, only NodeEntry components are ordered by their NodeID
-- while ProxyEntry components should never be tried to be ordered.
instance Ord CacheEntry where
a `compare` b = compare (extractID a) (extractID b)
where
extractID (NodeEntry _ eState _) = getNid eState
extractID (ProxyEntry _ _) = error "proxy entries should never appear outside of the NodeCache"
data ProxyDirection = Backwards
| Forwards
deriving (Show, Eq)
instance Enum ProxyDirection where
toEnum (-1) = Backwards
toEnum 1 = Forwards
toEnum _ = error "no such ProxyDirection"
fromEnum Backwards = - 1
fromEnum Forwards = 1
--- useful function for getting entries for a full cache transfer
cacheEntries :: NodeCache -> [CacheEntry]
cacheEntries ncache = mapMaybe extractNodeEntries $ Map.elems ncache
where
extractNodeEntries (ProxyEntry _ possibleEntry) = possibleEntry
-- | An empty @NodeCache@ needs to be initialised with 2 proxy entries,
-- linking the modular name space together by connecting @minBound@ and @maxBound@
initCache :: NodeCache
initCache = Map.fromList $ proxyEntry <$> [(maxBound, (minBound, Forwards)), (minBound, (maxBound, Backwards))]
where
proxyEntry (from,to) = (from, ProxyEntry to Nothing)
-- | Maybe returns the cache entry stored at given key
cacheLookup :: NodeID -- ^lookup key
-> NodeCache -- ^lookup cache
-> Maybe CacheEntry
cacheLookup key cache = case Map.lookup key cache of
Just (ProxyEntry _ result) -> result
res -> res
-- | a wrapper around lookup functions, making the lookup redirectable by a @ProxyEntry@
-- to simulate a modular ring
lookupWrapper :: (NodeID -> NodeCache -> Maybe (NodeID, CacheEntry)) -> (NodeID -> NodeCache -> Maybe (NodeID, CacheEntry)) -> ProxyDirection -> NodeID -> NodeCache -> Maybe CacheEntry
lookupWrapper f fRepeat direction key cache =
case f key cache of
-- the proxy entry found holds a
Just (_, ProxyEntry _ (Just entry@NodeEntry{})) -> Just entry
-- proxy entry holds another proxy entry, this should not happen
Just (_, ProxyEntry _ (Just (ProxyEntry _ _))) -> Nothing
-- proxy entry without own entry is a pointer on where to continue
-- if lookup direction is the same as pointer direction: follow pointer
Just (foundKey, ProxyEntry (pointerID, pointerDirection) Nothing) ->
let newKey = if pointerDirection == direction
then pointerID
else foundKey + (fromInteger . toInteger . fromEnum $ direction)
in if cacheNotEmpty cache
then lookupWrapper fRepeat fRepeat direction newKey cache
else Nothing
-- normal entries are returned
Just (_, entry@NodeEntry{}) -> Just entry
Nothing -> Nothing
where
cacheNotEmpty :: NodeCache -> Bool
cacheNotEmpty cache' = (Map.size cache' > 2) -- there are more than the 2 ProxyEntries
|| isJust ( cacheLookup minBound cache') -- or one of the ProxyEntries holds a node
|| isJust (cacheLookup maxBound cache')
-- | find the successor node to a given key on a modular EpiChord ring cache.
-- Note: The EpiChord definition of "successor" includes the node at the key itself,
-- if existing.
cacheLookupSucc :: NodeID -- ^lookup key
-> NodeCache -- ^ring cache
-> Maybe CacheEntry
cacheLookupSucc = lookupWrapper Map.lookupGE Map.lookupGE Forwards
-- | find the predecessor node to a given key on a modular EpiChord ring cache.
cacheLookupPred :: NodeID -- ^lookup key
-> NodeCache -- ^ring cache
-> Maybe CacheEntry
cacheLookupPred = lookupWrapper Map.lookupLT Map.lookupLE Backwards
-- clean up cache entries: once now - entry > maxAge
-- transfer difference now - entry to other node
-- | return the @NodeState@ data from a cache entry without checking its validation status
cacheGetNodeStateUnvalidated :: CacheEntry -> RemoteNodeState
cacheGetNodeStateUnvalidated (NodeEntry _ nState _) = nState
cacheGetNodeStateUnvalidated (ProxyEntry _ (Just entry)) = cacheGetNodeStateUnvalidated entry
cacheGetNodeStateUnvalidated _ = error "trying to pure empty node state, please report a bug"
-- | converts a 'HostAddress6' IP address to a big-endian strict ByteString
ipAddrAsBS :: HostAddress6 -> BS.ByteString
ipAddrAsBS (a, b, c, d) = mconcat $ fmap NetworkBytes.bytestring32 [a, b, c, d]
-- | converts a ByteString in big endian order to an IPv6 address 'HostAddress6'
bsAsIpAddr :: BS.ByteString -> HostAddress6
bsAsIpAddr bytes = (a,b,c,d)
where
a:b:c:d:_ = fmap NetworkBytes.word32 . chunkBytes 4 $ bytes
-- | generates a 256 bit long NodeID using SHAKE128, represented as ByteString
genNodeIDBS :: HostAddress6 -- ^a node's IPv6 address
-> String -- ^a node's 1st and 2nd level domain name
-> Word8 -- ^the used vserver ID
-> BS.ByteString -- ^the NodeID as a 256bit ByteString big-endian unsigned integer
genNodeIDBS ip nodeDomain vserver =
hashIpaddrUpper `BS.append` hashID nodeDomain' `BS.append` hashIpaddLower
where
vsBS = BS.pack [vserver] -- attention: only works for vserver IDs up to 255
ipaddrNet = BS.take 8 (ipAddrAsBS ip) `BS.append` vsBS
nodeDomain' = BSU.fromString nodeDomain `BS.append` vsBS
hashID bstr = BS.pack . BA.unpack $ (hash bstr :: Digest (SHAKE128 128))
(hashIpaddrUpper, hashIpaddLower) = BS.splitAt 64 $ hashID ipaddrNet
-- | generates a 256 bit long @NodeID@ using SHAKE128
genNodeID :: HostAddress6 -- ^a node's IPv6 address
-> String -- ^a node's 1st and 2nd level domain name
-> Word8 -- ^the used vserver ID
-> NodeID -- ^the generated @NodeID@
genNodeID ip nodeDomain vs = NodeID . byteStringToUInteger $ genNodeIDBS ip nodeDomain vs
-- | 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@
genKeyIDBS key = BS.pack . BA.unpack $ (hash (BSU.fromString key) :: Digest SHA3_256)
-- | generates a 256 bit long key identifier for looking up its data on the DHT
genKeyID :: String -- ^the key string
-> NodeID -- ^the key ID
genKeyID = NodeID . byteStringToUInteger . genKeyIDBS
-- | parses the bit pattern of a ByteString as an unsigned Integer in Big Endian order
-- by iterating it byte-wise from the back and shifting the byte values according to their offset
byteStringToUInteger :: BS.ByteString -> Integer
byteStringToUInteger bs = sum $ parsedBytes 0 bs
where
parsedBytes :: Integer -> BS.ByteString -> [ Integer ]
parsedBytes offset uintBs = case BS.unsnoc uintBs of
Nothing -> []
Just (bs', w) -> parseWithOffset offset w : parsedBytes (offset+1) bs'
parseWithOffset :: Integer -> Word8 -> Integer
parseWithOffset 0 word = toInteger word -- a shift of 0 is always 0
parseWithOffset offset word = toInteger word * 2^(8 * offset)
-- TODO: complete rewrite
-- |checks wether the cache entries fulfill the logarithmic EpiChord invariant
-- of having j entries per slice, and creates a list of necessary lookup actions.
-- Should be invoked periodically.
--checkCacheSlices :: NodeState -> IO [()]
--checkCacheSlices state = case getNodeCache state of
-- -- don't do anything on nodes without a cache
-- Nothing -> pure [()]
-- Just cache' -> checkSlice jEntries (nid state) startBound lastSucc =<< readIORef cache'
-- -- TODO: do the same for predecessors
-- where
-- jEntries = fromMaybe 0 $ getInternals_ jEntriesPerSlice state
-- lastSucc = last <$> maybeEmpty (fromMaybe [] $ getSuccessors state)
-- startBound = NodeID 2^(255::Integer) + nid state
-- checkSlice :: Int -> NodeID -> NodeID -> Maybe NodeID -> NodeCache -> [IO ()]
-- checkSlice _ _ _ Nothing _ = []
-- checkSlice j ownID upperBound (Just lastSuccNode) cache
-- | upperBound < lastSuccNode = []
-- | otherwise =
-- -- continuously half the DHT namespace, take the upper part as a slice,
-- -- check for existing entries in that slice and create a lookup action
-- -- and recursively do this on the lower half.
-- -- recursion edge case: all successors/ predecessors need to be in the
-- -- first slice.
-- let
-- diff = getNodeID $ upperBound - ownID
-- lowerBound = ownID + NodeID (diff `div` 2)
-- in
-- -- TODO: replace empty IO actions with actual lookups to middle of slice
-- -- TODO: validate ID before adding to cache
-- case Map.lookupLT upperBound cache of
-- Nothing -> pure () : checkSlice j ownID lowerBound (Just lastSuccNode) cache
-- Just (matchID, _) ->
-- if
-- matchID <= lowerBound then pure () : checkSlice j ownID lowerBound (Just lastSuccNode) cache
-- else
-- checkSlice j ownID lowerBound (Just lastSuccNode) cache
-- Todo: DHT backend can learn potential initial bootstrapping points through the instances mentioned in the received AP-relay messages
-- persist them on disk so they can be used for all following bootstraps
-- | configuration values used for initialising the FediChord DHT
data FediChordConf = FediChordConf
{ confDomain :: String
, confIP :: HostAddress6
, confDhtPort :: Int
}
deriving (Show, Eq)

6
src/Hash2Pub/ProtocolTypes.hs
View file

@ -3,7 +3,7 @@ module Hash2Pub.ProtocolTypes where
import qualified Data.Set as Set
import Data.Time.Clock.POSIX (POSIXTime)
import Hash2Pub.FediChord
import Hash2Pub.FediChordTypes
data QueryResponse = FORWARD (Set.Set RemoteCacheEntry)
| FOUND RemoteNodeState
@ -37,6 +37,10 @@ data FediChordMessage = Request
}
deriving (Show, Eq)
instance Ord FediChordMessage where
compare a b | requestID a == requestID b = part a `compare` part b
| otherwise = requestID a `compare` requestID b
data ActionPayload = QueryIDRequestPayload
{ queryTargetID :: NodeID
, queryLBestNodes :: Integer