Contents Index

Barracuda.ServerState Maintainer Henning Guenther, Martin Wegner, Stephan Friedrichs

Contents Types Monadic operations Running the ServerMonad Retrieving IDs Sending messages Accessing attributes General accessors Shortcuts Other accessors Auxiliary functions Logging and debugging

Description

This module contains a monad encapsulating the entire status of the distributor, so that it is completely free of side-effects. As a consequence, dumping the ServerState gives all information about why the distributor has made any decision.

Synopsis

data ServerMonad a data ServerState = ServST { routingTable :: SimpleRT chanList :: ChannelMap localUserInfo :: LocalUserInfo certificates :: CertificateList certificateRequests :: [CertificateRequest] userTimeOffsets :: (Map UserID (UTCTime, UTCTime)) randGen :: StdGen pendingAck :: (PendingAck InternalSignature) pendingAnonymous :: PendingAnonymous pendingKey :: PendingKey pendingRoute :: (PendingRoute InternalSignature) msgIds :: [MessageID] channelIdCounter :: Integer infrastructure :: (Maybe (Set SockAddr)) floodBuffer :: [(UserID, MessageID)] nextRouting :: UTCTime verbose :: Bool localhost :: String localhostAddr :: SockAddr wantsShutdown :: Bool } type CertificateCallback = Map UserID Certificate -> ServerMonad () type CertificateRequest = (Set UserID, Map UserID Certificate, CertificateCallback) type Accessor a b = (a -> (a, b)) -> ServerMonad b type SendCB = [MessageID] -> SockAddr -> InternalMessage -> IO [MessageID] runServerMonad :: SendCB -> Bool -> HostAddress -> Certificate -> PortNumber -> [(UTCTime, ServerMonad ())] -> IO () newMessageId :: ServerMonad MessageID newChannelId :: ServerMonad ChannelID sendMessage :: SockAddr -> InternalMessage -> ServerMonad () sendMessageBroadcast :: InternalMessage -> ServerMonad () sendUser :: UserID -> ControlResponse -> ServerMonad () sendUserBroadcast :: ControlResponse -> ServerMonad () with :: (ServerState -> a) -> (a -> ServerState -> ServerState) -> Accessor a b query :: (a -> b) -> a -> (a, b) manipulate :: (a -> a) -> a -> (a, ()) withCertificateRequests :: Accessor [CertificateRequest] b withCertificates :: Accessor CertificateList b withTimeOffsets :: Accessor (Map UserID (UTCTime, UTCTime)) b withChannelList :: Accessor ChannelMap b withLocalUserInfo :: Accessor LocalUserInfo b withPendingAck :: Accessor (PendingAck InternalSignature) b withPendingAnonymous :: Accessor PendingAnonymous b withPendingKey :: Accessor PendingKey b withPendingRoute :: Accessor (PendingRoute InternalSignature) b withRandom :: Accessor StdGen b newRandom :: ServerMonad StdGen withRoutingTable :: Accessor SimpleRT b rootCertificate :: ServerMonad Certificate curTime :: ServerMonad UTCTime shutdown :: ServerMonad () floodAgain :: UserID -> MessageID -> ServerMonad Bool isLocal :: UserID -> ServerMonad Bool partitionLocals :: Set UserID -> ServerMonad (Set UserID, Set UserID) btrace :: String -> ServerMonad () berror :: String -> ServerMonad ()

Types

data ServerMonad a

A Monad (MonadState) wrapping the ServerState and queues for output. Instances Monad ServerMonad MonadState ServerState ServerMonad

data ServerState

The state of the server. It holds all relevant data structures that store on the one hand information about the network and on the other hand the internal state of certain data such as open certificate requests and different structures waiting for different events (Pending*). Constructors ServST routingTable :: SimpleRT The currently known routing table to be used to route messages. chanList :: ChannelMap The list of currently known public and private channels. localUserInfo :: LocalUserInfo Stores information (UserID, PrivateKey, joined channels and a handle to send messages to the GUI of the user) about all locally connected users. certificates :: CertificateList Stores all known certificates. certificateRequests :: [CertificateRequest] Stores a list of CertificateRequests waiting for certain certificates. userTimeOffsets :: (Map UserID (UTCTime, UTCTime)) The time offsets to remote users. randGen :: StdGen Stores a random number generator. pendingAck :: (PendingAck InternalSignature) Stores messages that an ACK is awaited for. pendingAnonymous :: PendingAnonymous Stores anonymous messages to be monitored to be actually posted to the anonymous channel. pendingKey :: PendingKey Stores messages to be de- or encrypted that are waiting for a shared key of a channel. pendingRoute :: (PendingRoute InternalSignature) Stores messages that are waiting for a route to their destinations. msgIds :: [MessageID] An infinite list of unused MessageIDs. channelIdCounter :: Integer Counter for the ChannelIDs we use. infrastructure :: (Maybe (Set SockAddr)) Maybe stores a set of peers we are (only) connected with. floodBuffer :: [(UserID, MessageID)] Stores information about last received flood messages. nextRouting :: UTCTime Timestamp when routing messages have to be sent the next time. verbose :: Bool Whether to be verbose or not in output. localhost :: String Local hostname. localhostAddr :: SockAddr The local ip and port. wantsShutdown :: Bool The server wants to be shut down. Access this flag by shutdown rather than directly. Instances MonadState ServerState ServerMonad

type CertificateCallback = Map UserID Certificate -> ServerMonad ()

Required callback type for functions that want to be called when open certificate requests have been answered.

type CertificateRequest = (Set UserID, Map UserID Certificate, CertificateCallback)

Holds one certificate request. The first set holds all UserIDs we wait for a certificate from, the second map holds the already satisfied certificates and the third element is the callback to be called when all requests are satisfied.

type Accessor a b = (a -> (a, b)) -> ServerMonad b

Type specification for accessor functions (i. e. functions that work on the data structures in the ServerState).

type SendCB

= [MessageID] An infinite list of unused MessageIDs. -> SockAddr The target network address. -> InternalMessage This message has to be sent. -> IO [MessageID] Another infinite list of unused MessageIDs. The ones used must be removed. Such a function has to be provided to runServerMonad in order to enable it to perform necessary network output.

Monadic operations

Running the ServerMonad

runServerMonad

:: SendCB A send callback that performs pending network operations. -> Bool Indicates weather we're verbosed or not. -> HostAddress The broadcast address to use -> Certificate The root certificate for the network. -> PortNumber The portnumber, used for hostname generation -> [(UTCTime, ServerMonad ())] The actual list of timestamped operations to perform. -> IO () This function actually runs the entire ServerMonad structure. Given some configurational parameters and a callback to perform network output, it takes a list of timestamped instructions and performs the resulting IO.

Retrieving IDs

newMessageId :: ServerMonad MessageID

Generates a new unique MessageID.

newChannelId :: ServerMonad ChannelID

Generates a new unique ChannelID.

Sending messages

sendMessage :: SockAddr -> InternalMessage -> ServerMonad ()

Queues a message to be sent to the network.

sendMessageBroadcast :: InternalMessage -> ServerMonad ()

Takes a message to be broadcastet to the network and sends it.

sendUser :: UserID -> ControlResponse -> ServerMonad ()

Sends the given ControlResponse to the given user's GUI.

sendUserBroadcast :: ControlResponse -> ServerMonad ()

Sends the given ControlResponse to the GUIs of all connected users.

Accessing attributes

General accessors

with

:: (ServerState -> a) A getter function. -> (a -> ServerState -> ServerState) The setter function. -> Accessor a b Allows monadic access according to the callbacks above. The general accessor for The ServerState, that makes its attributs available in a monadic calculation. See also: query and manipulate, they make things easier.

query :: (a -> b) -> a -> (a, b)

Helper to wrap querying "non-monad functions" to work with the ServerMonad.

manipulate :: (a -> a) -> a -> (a, ())

Helper to wrap modifying "non-monad functions" to work with the ServerMonad.

Shortcuts

withCertificateRequests :: Accessor [CertificateRequest] b

Gives access for querying and manipulating the certificate request list.

withCertificates :: Accessor CertificateList b

Gives access for querying and manipulating the certificate list.

withTimeOffsets :: Accessor (Map UserID (UTCTime, UTCTime)) b

Gives access for querying and manipulating the user time offset list.

withChannelList :: Accessor ChannelMap b

Gives access for querying and manipulating the channel list.

withLocalUserInfo :: Accessor LocalUserInfo b

Gives access for querying and manipulating the local user info.

withPendingAck :: Accessor (PendingAck InternalSignature) b

Gives access for querying and manipulating the pending ack data structure.

withPendingAnonymous :: Accessor PendingAnonymous b

Gives access for querying and manipulating the pending anonymous data structure.

withPendingKey :: Accessor PendingKey b

Gives access for querying and manipulating the pending key data structure.

withPendingRoute :: Accessor (PendingRoute InternalSignature) b

Gives access for querying and manipulating the pending route data structure.

withRandom :: Accessor StdGen b

Gives access for querying and manipulating the random generator.

newRandom :: ServerMonad StdGen

Returns a new random generator

withRoutingTable :: Accessor SimpleRT b

Gives access for querying and manipulating the routing table.

Other accessors

rootCertificate :: ServerMonad Certificate

Returns the root certificate used to verify all other certificates.

curTime :: ServerMonad UTCTime

Returns the current time.

shutdown :: ServerMonad ()

Shut down the server. This is not rather done after processing the current DistributorMsg than immediately.

Auxiliary functions

floodAgain :: UserID -> MessageID -> ServerMonad Bool

Checks whether a flood message identified by the given UserID and MessageID was already received before.

isLocal :: UserID -> ServerMonad Bool

Checks whether the given UserID identifies a locally connected user or not.

partitionLocals :: Set UserID -> ServerMonad (Set UserID, Set UserID)

Splits a given set of users into (locals,non-locals)

Logging and debugging

btrace :: String -> ServerMonad ()

Used for rather verbosed output, for example for keeping track of an attribute. It only performs the output, if verbose is activated. For error messages use berror, to be sure it's printed!

berror :: String -> ServerMonad ()

Used for error output. This functions also performs output if verbose is deactivated. See also: btrace.

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