Network.Control

Common parts to control network protocols. This library assumes that Int is 64bit.

Flow control

This is based on the total approach of QUIC rather than the difference approach of HTTP/2 because QUIC'one is considered safer. Please refer to Using HTTP/3 Stream Limits in HTTP/2 to understand that QUIC's approaches are better though its topic is about stream concurrency.

Constants for flow control.

defaultMaxStreams :: Int

Default max streams. (64)

defaultMaxStreamData :: Int

Default max data of a stream. (256K bytes)

defaultMaxData :: Int

Default max data of a connection. (1M bytes)

Flow control for sending

data TxFlow

Flow for sending

-------------------------------------->
       ^           ^
    txfSent    txfLimit

       |-----------| The size which this node can send
       txWindowSize

Constructors

TxFlow

Fields

• txfSent :: Int

  The total size of sent data.

• txfLimit :: Int

  The total size of data which can be sent.

Instances

Show TxFlow

Defined in Network.Control.Flow

Methods

showsPrec :: Int -> TxFlow -> ShowS

show :: TxFlow -> String

showList :: [TxFlow] -> ShowS

Eq TxFlow

Defined in Network.Control.Flow

Methods

(==) :: TxFlow -> TxFlow -> Bool

(/=) :: TxFlow -> TxFlow -> Bool

newTxFlow :: WindowSize -> TxFlow

Creating TX flow with a receive buffer size.

txWindowSize :: TxFlow -> WindowSize

txfLimit - txfSent.

type WindowSize = Int

Window size.

Flow control for receiving

data RxFlow

Flow for receiving.

                rxfBufSize
       |------------------------|
-------------------------------------->
       ^            ^           ^
  rxfConsumed   rxfReceived  rxfLimit

                    |-----------| The size which the peer can send
                       Window

Constructors

RxFlow

Fields

• rxfBufSize :: Int

  Receive buffer size.

• rxfConsumed :: Int

  The total size which the application is consumed.

• rxfReceived :: Int

  The total already-received size.

• rxfLimit :: Int

  The total size which can be recived.

Instances

Show RxFlow

Defined in Network.Control.Flow

Methods

showsPrec :: Int -> RxFlow -> ShowS

show :: RxFlow -> String

showList :: [RxFlow] -> ShowS

Eq RxFlow

Defined in Network.Control.Flow

Methods

(==) :: RxFlow -> RxFlow -> Bool

(/=) :: RxFlow -> RxFlow -> Bool

newRxFlow :: WindowSize -> RxFlow

Creating RX flow with an initial window size.

data FlowControlType

The representation of window size update.

Constructors

FCTWindowUpdate

HTTP/2 style

FCTMaxData

QUIC style

maybeOpenRxWindow

Arguments

:: Int

The consumed size.

-> FlowControlType

-> RxFlow

-> (RxFlow, Maybe Int)

Just if the size should be informed to the peer.

When an application consumed received data, this function should be called to update rxfConsumed. If the available buffer size is less than the half of the total buffer size. the representation of window size update is returned.

Example:

                rxfBufSize
       |------------------------|
-------------------------------------->
       ^            ^           ^
  rxfConsumed   rxfReceived  rxfLimit
                    |01234567890|

In the case where the window update should be informed to the peer,
rxfConsumed and rxfLimit move to the right. The difference
of old and new rxfLimit is window update.

                  rxfBufSize
         |------------------------|
-------------------------------------->
         ^          ^             ^
    rxfConsumed rxfReceived    rxfLimit
                    |0123456789012| : window glows

Otherwise, only rxfConsumed moves to the right.

                rxfBufSize
       |------------------------|
-------------------------------------->
         ^          ^           ^
    rxfConsumed rxfReceived  rxfLimit
                    |01234567890| : window stays

checkRxLimit

Arguments

:: Int

The size of received data.

-> RxFlow

-> (RxFlow, Bool)

Acceptable if True.

Checking if received data is acceptable against the current window.

LRU cache

data LRUCache k v

Sized cache based on least recently used.

empty

Arguments

:: Int

The size of LRUCache.

-> LRUCache k v

Empty LRUCache.

insert :: Ord k => k -> v -> LRUCache k v -> LRUCache k v

Inserting.

delete :: Ord k => k -> LRUCache k v -> LRUCache k v

Deleting.

lookup :: Ord k => k -> LRUCache k v -> Maybe v

Looking up.

Rate control

data Rate

Type for rating.

newRate :: IO Rate

Creating a new Rate.

getRate :: Rate -> IO Int

Getting the current rate. If one or more seconds have passed since the previous call, the counter is re-initialized with 1 and it is returned. Otherwise, incremented counter number is returned.

addRate :: Rate -> Int -> IO Int

Getting the current rate. If one or more seconds have passed since the previous call, the counter is re-initialized with the second argument and it is returned. Otherwise, increased counter number is returned.