WIP: start implementing incoming request handling

This commit is contained in:
Trolli Schmittlauch 2020-05-30 01:09:17 +02:00
parent 96e61b726f
commit fea9660f80
3 changed files with 50 additions and 10 deletions

View file

@ -4,6 +4,7 @@ module Hash2Pub.DHTProtocol
, addCacheEntry
, addCacheEntryPure
, deleteCacheEntry
, deserialiseMessage
, markCacheEntryAsVerified
, RemoteCacheEntry(..)
, toRemoteCacheEntry
@ -19,6 +20,7 @@ module Hash2Pub.DHTProtocol
, resolve
, mkSendSocket
, mkServerSocket
, handleIncomingRequest
)
where
@ -31,6 +33,7 @@ import Control.Monad (foldM, forM, forM_)
import qualified Data.ByteString as BS
import Data.Either (rights)
import Data.Foldable (foldl', foldr')
import Data.Functor.Identity
import Data.IORef
import Data.IP (IPv6, fromHostAddress6,
toHostAddress6)
@ -141,8 +144,33 @@ markCacheEntryAsVerified timestamp = Map.adjust adjustFunc
adjustFunc (ProxyEntry _ (Just entry)) = adjustFunc entry
adjustFunc entry = entry
-- | uses the successor and predecessor list of a node as an indicator for whether a
-- node has properly joined the DHT
isJoined_ :: LocalNodeState -> Bool
isJoined_ ns = not . all null $ [successors ns, predecessors ns]
-- ====== message send and receive operations ======
handleIncomingRequest :: LocalNodeState -- ^ the handling node
-> TQueue (BS.ByteString, SockAddr) -- ^ send queue
-> FediChordMessage -- ^ request to handle
-> SockAddr -- ^ source address of the request
-> IO ()
handleIncomingRequest ns sendQ msg sourceAddr = do
-- add nodestate to cache
now <- getPOSIXTime
queueAddEntries (Identity . RemoteCacheEntry (sender msg) $ now) ns
-- distinguish on whether and how to respond
-- create and enqueue ACK
-- Idea: only respond with payload on last part (part == parts), problem: need to know partnumber of response from first part on
-- PLACEHOLDER
pure ()
-- ....... response sending .......
-- ....... request sending .......
-- | send a join request and return the joined 'LocalNodeState' including neighbours
requestJoin :: NodeState a => a -- ^ currently responsible node to be contacted
-> LocalNodeState -- ^ joining NodeState

View file

@ -53,10 +53,12 @@ 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 hiding (recv, recvFrom, send, sendTo)
import Network.Socket hiding (recv, recvFrom, send,
sendTo)
import Network.Socket.ByteString
-- for hashing and ID conversion
import Control.Concurrent
import Control.Concurrent.Async
import Control.Concurrent.STM
import Control.Concurrent.STM.TQueue
@ -213,12 +215,22 @@ fediMessageHandler :: TQueue (BS.ByteString, SockAddr) -- ^ send queue
-> IO ()
fediMessageHandler sendQ recvQ ns = forever $ do
-- wait for incoming messages
-- newMsg <- deserialiseMessage <$> recvFrom sock
-- either (\_ ->
-- -- ignore invalid messages
-- pure ()
-- )
-- (\aMsg ->
-- case aMsg of
-- aRequest@Request{} -> handleRequest
(rawMsg, sourceAddr) <- atomically $ readTQueue recvQ
let aMsg = deserialiseMessage rawMsg
-- handling multipart messages:
-- So far I handle the effects of each message part immedeiately, before making sure that and whether all parts have been received, based on the idea that even incomplete information is beneficial and handled idempotent.
-- If this turns out not to be the case, request parts can be insert into a map (key: (sender IP against spoofing, request ID), value: timestamp + set of message parts, handle all of them when size of set == parts) before being handled. This map needs to be purged periodically by a separate thread and can be protected by an MVar for fairness.
either (\_ ->
-- drop invalid messages
pure ()
)
(\validMsg ->
case validMsg of
aRequest@Request{} -> forkIO (handleIncomingRequest ns sendQ aRequest sourceAddr) >> pure ()
-- Responses should never arrive on the main server port, as they are always
-- responses to requests sent from dedicated sockets on another port
_ -> pure ()
)
aMsg
pure ()

View file

@ -4,7 +4,7 @@ import Control.Concurrent
import Control.Concurrent.Async
import Control.Exception
import Data.Either
import Data.IP (IPv6, toHostAddress6)
import Data.IP (IPv6, toHostAddress6)
import System.Environment
import Hash2Pub.FediChord