Hans.Tcp.Tcb

Timers

type SlowTicks = Int

data TcpTimers

Constructors

TcpTimers

Fields

• ttDelayedAck :: !Bool
• tt2MSL :: !SlowTicks
• ttRetransmitValid :: !Bool
• ttRetransmit :: !SlowTicks
• ttRetries :: !Int
• ttRTO :: !SlowTicks
• ttSRTT :: !NominalDiffTime
• ttRTTVar :: !NominalDiffTime
• ttMaxIdle :: !SlowTicks
• ttIdle :: !SlowTicks

emptyTcpTimers :: TcpTimers

resetRetransmit :: TcpTimers -> (TcpTimers, ())

Reset retransmit info.

retryRetransmit :: TcpTimers -> (TcpTimers, ())

Increment the retry count, and double the last retransmit timer.

stopRetransmit :: TcpTimers -> (TcpTimers, ())

Invalidate the retransmit timer.

reset2MSL :: Config -> TcpTimers -> (TcpTimers, ())

updateTimers :: TcpTimers -> (TcpTimers, TcpTimers)

Update all slow-tick timers. Return the old timers, for use with 'atomicModifyIORef\''.

calibrateRTO :: NominalDiffTime -> TcpTimers -> (TcpTimers, ())

Calibrate the RTO timer, given a round-trip measurement, as specified by RFC-6298.

TCB States

data State

Constructors

Listen

SynSent

SynReceived

Established

FinWait1

FinWait2

CloseWait

Closing

LastAck

TimeWait

Closed

Instances

Eq State

Methods

(==) :: State -> State -> Bool

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

Show State

Methods

showsPrec :: Int -> State -> ShowS

show :: State -> String

showList :: [State] -> ShowS

class GetState tcb where

Minimal complete definition

getState

Methods

getState :: tcb -> IO State

Instances

GetState TimeWaitTcb

Methods

getState :: TimeWaitTcb -> IO State

GetState Tcb

Methods

getState :: Tcb -> IO State

GetState ListenTcb

Methods

getState :: ListenTcb -> IO State

whenState :: (BaseM m IO, GetState tcb) => tcb -> State -> m () -> m ()

setState :: Tcb -> State -> IO ()

The Tcb type is the only one that supports changing state.

Sending

class CanSend sock where

Minimal complete definition

getSendWindow

Methods

getSendWindow :: BaseM io IO => sock -> io (TcpSeqNum, TcpSeqNum)

Instances

CanSend Tcb

Methods

getSendWindow :: BaseM io IO => Tcb -> io (TcpSeqNum, TcpSeqNum)

CanSend (IORef Window)

Methods

getSendWindow :: BaseM io IO => IORef Window -> io (TcpSeqNum, TcpSeqNum)

getSndNxt :: (BaseM io IO, CanSend sock) => sock -> io TcpSeqNum

getSndWnd :: (BaseM io IO, CanSend sock) => sock -> io TcpSeqNum

Receiving

class CanReceive sock where

Minimal complete definition

getRecvWindow

Methods

getRecvWindow :: BaseM io IO => sock -> io (TcpSeqNum, TcpSeqNum)

Retrieve the left and right edges of the receive window:

(RCV.NXT, RCV.NXT + RCV.WND)

Instances

CanReceive TimeWaitTcb

Methods

getRecvWindow :: BaseM io IO => TimeWaitTcb -> io (TcpSeqNum, TcpSeqNum)

CanReceive Tcb

Methods

getRecvWindow :: BaseM io IO => Tcb -> io (TcpSeqNum, TcpSeqNum)

CanReceive (IORef Window)

Methods

getRecvWindow :: BaseM io IO => IORef Window -> io (TcpSeqNum, TcpSeqNum)

getRcvNxt :: (BaseM io IO, CanReceive sock) => sock -> io TcpSeqNum

getRcvWnd :: (BaseM io IO, CanReceive sock) => sock -> io Word16

getRcvRight :: (BaseM io IO, CanReceive sock) => sock -> io TcpSeqNum

Listening TCBs

data ListenTcb

Constructors

ListenTcb

Fields

• lSrc :: !Addr
• lPort :: !TcpPort
• lAccept :: !(IORef AcceptQueue)
• lAcceptSignal :: !Signal
• lTSClock :: !(IORef TSClock)

Instances

GetState ListenTcb

Methods

getState :: ListenTcb -> IO State

newListenTcb :: Addr -> TcpPort -> Int -> IO ListenTcb

Create a new listening socket.

createChild

Arguments

:: HasConfig cfg

=> cfg

-> TcpSeqNum

-> ListenTcb

-> RouteInfo Addr

-> Addr

-> TcpHeader

-> (Tcb -> State -> IO ())

On Established

-> (Tcb -> State -> IO ())

On Closed

-> IO Tcb

Create a child from a Syn request.

reserveSlot :: ListenTcb -> IO Bool

Reserve a slot in the accept queue, returns True when the space has been reserved.

releaseSlot :: ListenTcb -> IO ()

Release a slot back to the accept queue.

acceptTcb :: ListenTcb -> IO Tcb

Wait until a Tcb is available in the accept queue.

Active TCBs

data Tcb

Constructors

Tcb

Fields

• tcbParent :: Maybe ListenTcb

  Parent to notify if this tcb was generated from a socket in the LISTEN state

• tcbConfig :: !(IORef TcbConfig)
• tcbState :: !(IORef State)
• tcbEstablished :: Tcb -> State -> IO ()
• tcbClosed :: Tcb -> State -> IO ()
• tcbSndUp :: !SeqNumVar

  SND.UP

• tcbSndWl1 :: !SeqNumVar

  SND.WL1

• tcbSndWl2 :: !SeqNumVar

  SND.WL2

• tcbIss :: !SeqNumVar

  ISS

• tcbSendWindow :: !(IORef Window)
• tcbRcvUp :: !SeqNumVar

  RCV.UP

• tcbIrs :: !SeqNumVar

  IRS

• tcbNeedsDelayedAck :: !(IORef Bool)
• tcbRecvWindow :: !(IORef Window)
• tcbRecvBuffer :: !Buffer
• tcbLocalPort :: !TcpPort

  Local port

• tcbRemotePort :: !TcpPort

  Remote port

• tcbRouteInfo :: !(RouteInfo Addr)

  Cached routing

• tcbRemote :: !Addr

  Remote host

• tcbMss :: !(IORef Int64)

  Maximum segment size

• tcbTimers :: !(IORef TcpTimers)
• tcbTSRecent :: !(IORef Word32)
• tcbLastAckSent :: !(IORef TcpSeqNum)

Instances

CanReceive Tcb

Methods

getRecvWindow :: BaseM io IO => Tcb -> io (TcpSeqNum, TcpSeqNum)

CanSend Tcb

Methods

getSendWindow :: BaseM io IO => Tcb -> io (TcpSeqNum, TcpSeqNum)

GetState Tcb

Methods

getState :: Tcb -> IO State

newTcb

Arguments

:: HasConfig state

=> state

-> Maybe ListenTcb

-> TcpSeqNum

ISS

-> RouteInfo Addr

-> TcpPort

-> Addr

-> TcpPort

-> State

-> TSClock

-> (Tcb -> State -> IO ())

-> (Tcb -> State -> IO ())

-> IO Tcb

signalDelayedAck :: Tcb -> IO ()

Record that a delayed ack should be sent.

setRcvNxt :: TcpSeqNum -> Tcb -> IO Bool

Set the value of RCV.NXT. Returns True when the value has been set successfully, and False if the receive queue was not empty.

finalizeTcb :: Tcb -> IO ()

Cleanup the Tcb.

getSndUna :: BaseM io IO => Tcb -> io TcpSeqNum

resetIdleTimer :: TcpTimers -> (TcpTimers, ())

Reset idle timer in the presence of packets, for use with 'atomicModifyIORef\''.

Active Config

data TcbConfig

Constructors

TcbConfig

Fields

• tcUseTimestamp :: !Bool

usingTimestamps :: Tcb -> IO Bool

True when the timestamp option should be included.

disableTimestamp :: Tcb -> IO ()

Disable the use of the timestamp option.

Windowing

queueBytes :: ByteString -> Tcb -> IO ()

Queue bytes in the receive buffer.

haveBytesAvail :: Tcb -> IO Bool

Determine if there are bytes in the receive buffer that can be read.

receiveBytes :: Int -> Tcb -> IO ByteString

Remove data from the receive buffer, and move the right-side of the receive window. Reading 0 bytes indicates that the remote side has closed the connection.

tryReceiveBytes :: Int -> Tcb -> IO (Maybe ByteString)

Non-blocking version of receiveBytes. Reading 0 bytes indicates that the remote side has closed the connection.

TimeWait TCBs

data TimeWaitTcb

Constructors

TimeWaitTcb

Fields

• twSndNxt :: !TcpSeqNum

  SND.NXT

• twRcvNxt :: !SeqNumVar

  RCV.NXT

• twRcvWnd :: !Word16

  RCV.WND

• twLocalPort :: !TcpPort
• twRemotePort :: !TcpPort
• twRouteInfo :: !(RouteInfo Addr)
• twRemote :: !Addr

Instances

Eq TimeWaitTcb

Methods

(==) :: TimeWaitTcb -> TimeWaitTcb -> Bool

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

CanReceive TimeWaitTcb

Methods

getRecvWindow :: BaseM io IO => TimeWaitTcb -> io (TcpSeqNum, TcpSeqNum)

GetState TimeWaitTcb

Methods

getState :: TimeWaitTcb -> IO State

mkTimeWaitTcb :: Tcb -> IO TimeWaitTcb