System.Socket

{-# LANGUAGE OverloadedStrings #-}
module Main where

import Control.Exception ( bracket, catch )
import Control.Monad ( forever )

import System.Socket
import System.Socket.Family.Inet6
import System.Socket.Type.Stream
import System.Socket.Protocol.TCP

main :: IO ()
main = bracket
  ( socket :: IO (Socket Inet6 Stream TCP) )
  ( \s-> do
    close s
    putStrLn "Listening socket closed."
  )
  ( \s-> do
    setSocketOption s (ReuseAddress True)
    setSocketOption s (V6Only False)
    bind s (SocketAddressInet6 inet6Any 8080 0 0)
    listen s 5
    putStrLn "Listening socket ready..."
    forever $ acceptAndHandle s `catch` \e-> print (e :: SocketException)
  )

acceptAndHandle :: Socket Inet6 Stream TCP -> IO ()
acceptAndHandle s = bracket
  ( accept s )
  ( \(p, addr)-> do
    close p
    putStrLn $ "Closed connection to " ++ show addr
  )
  ( \(p, addr)-> do
    putStrLn $ "Accepted connection from " ++ show addr
    sendAll p "Hello world!" msgNoSignal
  )

Socket

data Socket f t p

A generic socket type. Use socket to create a new socket.

The socket is just an MVar-wrapped file descriptor. The Socket constructor is exported trough the unsafe module in order to make this library easily extensible, but it is usually not necessary nor advised to work directly on the file descriptor. If you do, the following rules must be obeyed:

• Make sure not to deadlock. Use withMVar or similar.
• The lock must not be held during a blocking call. This would make it impossible to send and receive simultaneously or to close the socket.
• The lock must be held when calling operations that use the file descriptor. Otherwise the socket might get closed or even reused by another thread/capability which might result in reading from or writing on a totally different socket. This is a security nightmare!
• The socket is non-blocking and all the code relies on that assumption. You need to use GHC's eventing mechanism primitives to block until something happens. The former rules forbid to use threadWaitRead as it does not separate between registering the file descriptor (for which the lock must be held) and the actual waiting (for which you must not hold the lock). Also see this thread and read the library code to see how the problem is currently circumvented.

Family

class Storable (SocketAddress f) => Family f where

The address Family determines the network protocol to use.

The most common address families are Inet (IPv4) and Inet6 (IPv6).

Associated Types

data SocketAddress f

The SocketAddress type is a data family. This allows to provide different data constructors depending on the socket family without knowing all of them in advance or the need to extend this core library.

SocketAddressInet  inetLoopback  8080     :: SocketAddress Inet
SocketAddressInet6 inet6Loopback 8080 0 0 :: SocketAddress Inet6

Methods

familyNumber :: f -> CInt

The number designating this Family on the specific platform. This method is only exported for implementing extension libraries.

This function shall yield the values of constants like AF_INET, AF_INET6 etc.

Instances

Family Inet

Defined in System.Socket.Family.Inet

Associated Types

data SocketAddress Inet :: Type

Methods

familyNumber :: Inet -> CInt

Family Inet6

Defined in System.Socket.Family.Inet6

Associated Types

data SocketAddress Inet6 :: Type

Methods

familyNumber :: Inet6 -> CInt

Type

class Type t where

The Type determines properties of the transport layer and the semantics of basic socket operations.

The instances supplied by this library are Raw (no transport layer), Stream (for unframed binary streams, e.g. TCP), Datagram (for datagrams of limited length, e.g. UDP) and SequentialPacket (for framed messages of arbitrary length, e.g. SCTP).

Methods

typeNumber :: t -> CInt

This number designates this Type on the specific platform. This method is only exported for implementing extension libraries.

The function shall yield the values of constants like SOCK_STREAM, SOCK_DGRAM etc.

Instances

Type Datagram

Defined in System.Socket.Type.Datagram

Methods

typeNumber :: Datagram -> CInt

Type Raw

Defined in System.Socket.Type.Raw

Methods

typeNumber :: Raw -> CInt

Type SequentialPacket

Defined in System.Socket.Type.SequentialPacket

Methods

typeNumber :: SequentialPacket -> CInt

Type Stream

Defined in System.Socket.Type.Stream

Methods

typeNumber :: Stream -> CInt

Protocol

class Protocol p where

The Protocol determines the transport protocol to use.

Use Default to let the operating system choose a transport protocol compatible with the socket's Type.

Methods

protocolNumber :: p -> CInt

This number designates this Protocol on the specific platform. This method is only exported for implementing extension libraries.

The function shall yield the values of constants like IPPROTO_TCP, IPPROTO_UDP etc.

Instances

Protocol Default

Defined in System.Socket.Protocol.Default

Methods

protocolNumber :: Default -> CInt

Protocol TCP

Defined in System.Socket.Protocol.TCP

Methods

protocolNumber :: TCP -> CInt

Protocol UDP

Defined in System.Socket.Protocol.UDP

Methods

protocolNumber :: UDP -> CInt

Operations

socket

socket :: (Family f, Type t, Protocol p) => IO (Socket f t p)

Creates a new socket.

Whereas the underlying POSIX socket operation takes 3 parameters, this library encodes this information in the type variables. This rules out several kinds of errors and especially simplifies the handling of addresses (by using associated data families). Examples:

-- create an IPv4-UDP-datagram socket
sock <- socket :: IO (Socket Inet Datagram UDP)
-- create an IPv6-TCP-streaming socket
sock6 <- socket :: IO (Socket Inet6 Stream TCP)
-- create an IPv6-streaming socket with default protocol (usually TCP)
sock6 <- socket :: IO (Socket Inet6 Strem Default)

• This operation sets up a finalizer that automatically closes the socket when the garbage collection decides to collect it. This is just a fail-safe. You might still run out of file descriptors as there's no guarantee about when the finalizer is run. You're advised to manually close the socket when it's no longer needed. If possible, use bracket to reliably close the socket descriptor on exception or regular termination of your computation:

result <- bracket (socket :: IO (Socket Inet6 Stream TCP)) close $ \sock-> do
  somethingWith sock -- your computation here
  return somethingelse

• This operation configures the socket non-blocking to work seamlessly with the runtime system's event notification mechanism.
• This operation can safely deal with asynchronous exceptions without leaking file descriptors.
• This operation throws SocketExceptions. Consult your man socket for details and specific errors.

connect

connect :: Family f => Socket f t p -> SocketAddress f -> IO ()

Connects to a remote address.

• This operation returns as soon as a connection has been established (as if the socket were blocking). The connection attempt has either failed or succeeded after this operation threw an exception or returned.
• The operation throws SocketExceptions. Calling connect on a closed socket throws eBadFileDescriptor even if the former file descriptor has been reassigned.

bind

bind :: Family f => Socket f t p -> SocketAddress f -> IO ()

Bind a socket to an address.

• Calling bind on a closed socket throws eBadFileDescriptor even if the former file descriptor has been reassigned.
• It is assumed that bind never blocks and therefore eInProgress, eAlready and eInterrupted don't occur. This assumption is supported by the fact that the Linux manpage doesn't mention any of these errors, the Posix manpage doesn't mention the last one and even MacOS' implementation will never fail with any of these when the socket is configured non-blocking as argued here.
• This operation throws SocketExceptions. Consult your man page for details and specific errnos.

listen

listen :: Socket f t p -> Int -> IO ()

Starts listening and queueing connection requests on a connection-mode socket. The second parameter determines the backlog size.

• Calling listen on a closed socket throws eBadFileDescriptor even if the former file descriptor has been reassigned.
• The second parameter is called backlog and sets a limit on how many unaccepted connections the transport implementation shall queue. A value of 0 leaves the decision to the implementation.
• This operation throws SocketExceptions. Consult your man listen for details and specific errors.

accept

accept :: Family f => Socket f t p -> IO (Socket f t p, SocketAddress f)

Accept a new connection.

• Calling accept on a closed socket throws eBadFileDescriptor even if the former file descriptor has been reassigned.
• This operation configures the new socket non-blocking. It uses accept4 (when available) in order to accept and set the socket non-blocking with a single system call.
• This operation sets up a finalizer for the new socket that automatically closes the new socket when the garbage collection decides to collect it. This is just a fail-safe. You might still run out of file descriptors as there's no guarantee about when the finalizer is run. You're advised to manually close the socket when it's no longer needed.
• This operation throws SocketExceptions.
• This operation catches eAgain, eWouldBlock and eInterrupted internally and retries automatically.

send, sendTo

send :: Socket f t p -> ByteString -> MessageFlags -> IO Int

Send data.

• Calling send on a closed socket throws eBadFileDescriptor even if the former file descriptor has been reassigned.
• The operation returns the number of bytes sent. On Datagram and SequentialPacket sockets certain assurances on atomicity exist and eAgain or eWouldBlock are thrown until the whole message would fit into the send buffer.
• This operation throws SocketExceptions. Consult man send for details and specific errors.
• eAgain, eWouldBlock and eInterrupted and handled internally and won't be thrown. For performance reasons the operation first tries a write on the socket and then waits when it got eAgain or eWouldBlock.

sendTo :: Family f => Socket f t p -> ByteString -> MessageFlags -> SocketAddress f -> IO Int

Like send, but allows to specify a destination address.

receive, receiveFrom

receive :: Socket f t p -> Int -> MessageFlags -> IO ByteString

Receive data.

• The operation takes a buffer size in bytes a first parameter which limits the maximum length of the returned ByteString.
• When an empty ByteString is returned this usally (protocol specific) means that the peer gracefully closed the connection. The user is advised to check for and handle this case.
• Calling receive on a closed socket throws eBadFileDescriptor even if the former file descriptor has been reassigned.
• This operation throws SocketExceptions. Consult man recv for details and specific errors.
• eAgain, eWouldBlock and eInterrupted and handled internally and won't be thrown. For performance reasons the operation first tries a read on the socket and then waits when it got eAgain or eWouldBlock until the socket is signaled to be readable.

receiveFrom :: Family f => Socket f t p -> Int -> MessageFlags -> IO (ByteString, SocketAddress f)

Like receive, but additionally yields the peer address.

close

close :: Socket f t p -> IO ()

Closes a socket.

• This operation is idempotent and thus can be performed more than once without throwing an exception. If it throws an exception it is presumably a not recoverable situation and the process should exit.
• This operation does not block.
• This operation wakes up all threads that are currently blocking on this socket. All other threads are guaranteed to not block on operations on this socket in the future. Threads that perform operations other than close on this socket will fail with eBadFileDescriptor after the socket has been closed (close replaces the Fd in the MVar with -1 to reliably avoid use-after-free situations).
• This operation potentially throws SocketExceptions (only EIO is documented). eInterrupted is catched internally and retried automatically, so won't be thrown.

Name Resolution

getAddress

getAddress :: Family f => Socket f t p -> IO (SocketAddress f)

Get a socket's (local) address.

> (socket :: IO (Socket Inet Stream TCP)) >>= getAddress
SocketAddressInet {inetAddress = InetAddress 0.0.0.0, inetPort = InetPort 0}

• The operation throws SocketExceptions. Calling getAddress on a closed socket throws eBadFileDescriptor even if the former file descriptor has been reassigned.
• Behaviour of calling getAddress on a socket that is neither bound nor connected is undefined.

getAddressInfo

data AddressInfo f t p

Constructors

AddressInfo

Fields

• addressInfoFlags :: AddressInfoFlags
• socketAddress :: SocketAddress f
• canonicalName :: Maybe ByteString

Instances

Eq (SocketAddress f) => Eq (AddressInfo f t p)

Defined in System.Socket.Internal.AddressInfo

Methods

(==) :: AddressInfo f t p -> AddressInfo f t p -> Bool

(/=) :: AddressInfo f t p -> AddressInfo f t p -> Bool

Show (SocketAddress f) => Show (AddressInfo f t p)

Defined in System.Socket.Internal.AddressInfo

Methods

showsPrec :: Int -> AddressInfo f t p -> ShowS

show :: AddressInfo f t p -> String

showList :: [AddressInfo f t p] -> ShowS

class Family f => HasAddressInfo f where

This class is for address families that support name resolution.

Methods

getAddressInfo :: (Type t, Protocol p) => Maybe ByteString -> Maybe ByteString -> AddressInfoFlags -> IO [AddressInfo f t p]

Maps names to addresses (i.e. by DNS lookup).

The operation throws AddressInfoExceptions.

Contrary to the underlying getaddrinfo operation this wrapper is typesafe and thus only returns records that match the address, type and protocol encoded in the type. This is the price we have to pay for typesafe sockets and extensibility.

If you need different types of records, you need to start several queries. If you want to connect to both IPv4 and IPV6 addresses use aiV4Mapped and use IPv6-sockets.

getAddressInfo (Just "www.haskell.org") (Just "https") mempty :: IO [AddressInfo Inet Stream TCP]
> [AddressInfo {addressInfoFlags = AddressInfoFlags 0, socketAddress = SocketAddressInet {inetAddress = InetAddress 162.242.239.16, inetPort = InetPort 443}, canonicalName = Nothing}]

> getAddressInfo (Just "www.haskell.org") (Just "80") aiV4Mapped :: IO [AddressInfo Inet6 Stream TCP]
[AddressInfo {
   addressInfoFlags = AddressInfoFlags 8,
   socketAddress    = SocketAddressInet6 {inet6Address = Inet6Address 2400:cb00:2048:0001:0000:0000:6ca2:cc3c, inet6Port = Inet6Port 80, inet6FlowInfo = Inet6FlowInfo 0, inet6ScopeId = Inet6ScopeId 0},
   canonicalName    = Nothing }]

> getAddressInfo (Just "darcs.haskell.org") Nothing aiV4Mapped :: IO [AddressInfo Inet6 Stream TCP]
[AddressInfo {
   addressInfoFlags = AddressInfoFlags 8,
   socketAddress    = SocketAddressInet6 {inet6Address = Inet6Address 0000:0000:0000:0000:0000:ffff:17fd:e1ad, inet6Port = Inet6Port 0, inet6FlowInfo = Inet6FlowInfo 0, inet6ScopeId = Inet6ScopeId 0},
   canonicalName    = Nothing }]
> getAddressInfo (Just "darcs.haskell.org") Nothing mempty :: IO [AddressInfo Inet6 Stream TCP]
*** Exception: AddressInfoException "Name or service not known"

Instances

HasAddressInfo Inet

Defined in System.Socket.Internal.AddressInfo

Methods

getAddressInfo :: (Type t, Protocol p) => Maybe ByteString -> Maybe ByteString -> AddressInfoFlags -> IO [AddressInfo Inet t p]

HasAddressInfo Inet6

Defined in System.Socket.Internal.AddressInfo

Methods

getAddressInfo :: (Type t, Protocol p) => Maybe ByteString -> Maybe ByteString -> AddressInfoFlags -> IO [AddressInfo Inet6 t p]

getNameInfo

data NameInfo

A NameInfo consists of host and service name.

Constructors

NameInfo

Fields

• hostName :: ByteString
• serviceName :: ByteString

Instances

Eq NameInfo

Defined in System.Socket.Internal.AddressInfo

Methods

(==) :: NameInfo -> NameInfo -> Bool

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

Show NameInfo

Defined in System.Socket.Internal.AddressInfo

Methods

showsPrec :: Int -> NameInfo -> ShowS

show :: NameInfo -> String

showList :: [NameInfo] -> ShowS

class Family f => HasNameInfo f where

This class is for address families that support reverse name resolution.

Methods

getNameInfo :: SocketAddress f -> NameInfoFlags -> IO NameInfo

(Reverse-)map an address back to a human-readable host- and service name.

The operation throws AddressInfoExceptions.

> getNameInfo (SocketAddressInet inetLoopback 80) mempty
NameInfo {hostName = "localhost.localdomain", serviceName = "http"}

Instances

HasNameInfo Inet

Defined in System.Socket.Internal.AddressInfo

Methods

getNameInfo :: SocketAddress Inet -> NameInfoFlags -> IO NameInfo

HasNameInfo Inet6

Defined in System.Socket.Internal.AddressInfo

Methods

getNameInfo :: SocketAddress Inet6 -> NameInfoFlags -> IO NameInfo

Options

class SocketOption o where

SocketOptions allow to read and write certain properties of a socket.

• Each option shall have a corresponding data type that models the data associated with the socket option.
• Use unsafeGetSocketOption and unsafeSetSocketOption in order to implement custom socket options.

Methods

getSocketOption :: Socket f t p -> IO o

Get a specific SocketOption.

• This operation throws SocketExceptions. Consult man getsockopt for details and specific errors.

setSocketOption :: Socket f t p -> o -> IO ()

Set a specific SocketOption.

• This operation throws SocketExceptions. Consult man setsockopt for details and specific errors.

Instances

SocketOption KeepAlive

Defined in System.Socket.Internal.SocketOption

Methods

getSocketOption :: Socket f t p -> IO KeepAlive

setSocketOption :: Socket f t p -> KeepAlive -> IO ()

SocketOption ReuseAddress

Defined in System.Socket.Internal.SocketOption

Methods

getSocketOption :: Socket f t p -> IO ReuseAddress

setSocketOption :: Socket f t p -> ReuseAddress -> IO ()

SocketOption Error

Defined in System.Socket.Internal.SocketOption

Methods

getSocketOption :: Socket f t p -> IO Error

setSocketOption :: Socket f t p -> Error -> IO ()

SocketOption V6Only

Defined in System.Socket.Family.Inet6

Methods

getSocketOption :: Socket f t p -> IO V6Only

setSocketOption :: Socket f t p -> V6Only -> IO ()

SocketOption NoDelay

Defined in System.Socket.Protocol.TCP

Methods

getSocketOption :: Socket f t p -> IO NoDelay

setSocketOption :: Socket f t p -> NoDelay -> IO ()

Error

data Error

Reports the last error that occured on the socket.

• Also known as SO_ERROR.
• The operation setSocketOption always throws eInvalid for this option.
• Use with care in the presence of concurrency!

Constructors

Error SocketException

Instances

Eq Error

Defined in System.Socket.Internal.SocketOption

Methods

(==) :: Error -> Error -> Bool

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

Ord Error

Defined in System.Socket.Internal.SocketOption

Methods

compare :: Error -> Error -> Ordering

(<) :: Error -> Error -> Bool

(<=) :: Error -> Error -> Bool

(>) :: Error -> Error -> Bool

(>=) :: Error -> Error -> Bool

max :: Error -> Error -> Error

min :: Error -> Error -> Error

Show Error

Defined in System.Socket.Internal.SocketOption

Methods

showsPrec :: Int -> Error -> ShowS

show :: Error -> String

showList :: [Error] -> ShowS

SocketOption Error

Defined in System.Socket.Internal.SocketOption

Methods

getSocketOption :: Socket f t p -> IO Error

setSocketOption :: Socket f t p -> Error -> IO ()

ReuseAddress

data ReuseAddress

Allows or disallows the reuse of a local address in a bind call.

• Also known as SO_REUSEADDR.
• This is particularly useful when experiencing eAddressInUse exceptions.

Constructors

ReuseAddress Bool

Instances

Eq ReuseAddress

Defined in System.Socket.Internal.SocketOption

Methods

(==) :: ReuseAddress -> ReuseAddress -> Bool

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

Ord ReuseAddress

Defined in System.Socket.Internal.SocketOption

Methods

compare :: ReuseAddress -> ReuseAddress -> Ordering

(<) :: ReuseAddress -> ReuseAddress -> Bool

(<=) :: ReuseAddress -> ReuseAddress -> Bool

(>) :: ReuseAddress -> ReuseAddress -> Bool

(>=) :: ReuseAddress -> ReuseAddress -> Bool

max :: ReuseAddress -> ReuseAddress -> ReuseAddress

min :: ReuseAddress -> ReuseAddress -> ReuseAddress

Show ReuseAddress

Defined in System.Socket.Internal.SocketOption

Methods

showsPrec :: Int -> ReuseAddress -> ShowS

show :: ReuseAddress -> String

showList :: [ReuseAddress] -> ShowS

SocketOption ReuseAddress

Defined in System.Socket.Internal.SocketOption

Methods

getSocketOption :: Socket f t p -> IO ReuseAddress

setSocketOption :: Socket f t p -> ReuseAddress -> IO ()

KeepAlive

data KeepAlive

When enabled the protocol checks in a protocol-specific manner if the other end is still alive.

• Also known as SO_KEEPALIVE.

Constructors

KeepAlive Bool

Instances

Eq KeepAlive

Defined in System.Socket.Internal.SocketOption

Methods

(==) :: KeepAlive -> KeepAlive -> Bool

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

Ord KeepAlive

Defined in System.Socket.Internal.SocketOption

Methods

compare :: KeepAlive -> KeepAlive -> Ordering

(<) :: KeepAlive -> KeepAlive -> Bool

(<=) :: KeepAlive -> KeepAlive -> Bool

(>) :: KeepAlive -> KeepAlive -> Bool

(>=) :: KeepAlive -> KeepAlive -> Bool

max :: KeepAlive -> KeepAlive -> KeepAlive

min :: KeepAlive -> KeepAlive -> KeepAlive

Show KeepAlive

Defined in System.Socket.Internal.SocketOption

Methods

showsPrec :: Int -> KeepAlive -> ShowS

show :: KeepAlive -> String

showList :: [KeepAlive] -> ShowS

SocketOption KeepAlive

Defined in System.Socket.Internal.SocketOption

Methods

getSocketOption :: Socket f t p -> IO KeepAlive

setSocketOption :: Socket f t p -> KeepAlive -> IO ()

Flags

MessageFlags

newtype MessageFlags

Use the Monoid instance to combine several flags:

mconcat [msgNoSignal, msgWaitAll]

Use the Bits instance to check whether a flag is set:

if flags .&. msgEndOfRecord /= mempty then ...

Constructors

MessageFlags CInt

Instances

Eq MessageFlags

Defined in System.Socket.Internal.Message

Methods

(==) :: MessageFlags -> MessageFlags -> Bool

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

Show MessageFlags

Defined in System.Socket.Internal.Message

Methods

showsPrec :: Int -> MessageFlags -> ShowS

show :: MessageFlags -> String

showList :: [MessageFlags] -> ShowS

Semigroup MessageFlags

Defined in System.Socket.Internal.Message

Methods

(<>) :: MessageFlags -> MessageFlags -> MessageFlags

sconcat :: NonEmpty MessageFlags -> MessageFlags

stimes :: Integral b => b -> MessageFlags -> MessageFlags

Monoid MessageFlags

Defined in System.Socket.Internal.Message

Methods

mempty :: MessageFlags

mappend :: MessageFlags -> MessageFlags -> MessageFlags

mconcat :: [MessageFlags] -> MessageFlags

Storable MessageFlags

Defined in System.Socket.Internal.Message

Methods

sizeOf :: MessageFlags -> Int

alignment :: MessageFlags -> Int

peekElemOff :: Ptr MessageFlags -> Int -> IO MessageFlags

pokeElemOff :: Ptr MessageFlags -> Int -> MessageFlags -> IO ()

peekByteOff :: Ptr b -> Int -> IO MessageFlags

pokeByteOff :: Ptr b -> Int -> MessageFlags -> IO ()

peek :: Ptr MessageFlags -> IO MessageFlags

poke :: Ptr MessageFlags -> MessageFlags -> IO ()

Bits MessageFlags

Defined in System.Socket.Internal.Message

Methods

(.&.) :: MessageFlags -> MessageFlags -> MessageFlags

(.|.) :: MessageFlags -> MessageFlags -> MessageFlags

xor :: MessageFlags -> MessageFlags -> MessageFlags

complement :: MessageFlags -> MessageFlags

shift :: MessageFlags -> Int -> MessageFlags

rotate :: MessageFlags -> Int -> MessageFlags

zeroBits :: MessageFlags

bit :: Int -> MessageFlags

setBit :: MessageFlags -> Int -> MessageFlags

clearBit :: MessageFlags -> Int -> MessageFlags

complementBit :: MessageFlags -> Int -> MessageFlags

testBit :: MessageFlags -> Int -> Bool

bitSizeMaybe :: MessageFlags -> Maybe Int

bitSize :: MessageFlags -> Int

isSigned :: MessageFlags -> Bool

shiftL :: MessageFlags -> Int -> MessageFlags

unsafeShiftL :: MessageFlags -> Int -> MessageFlags

shiftR :: MessageFlags -> Int -> MessageFlags

unsafeShiftR :: MessageFlags -> Int -> MessageFlags

rotateL :: MessageFlags -> Int -> MessageFlags

rotateR :: MessageFlags -> Int -> MessageFlags

popCount :: MessageFlags -> Int

msgNoSignal :: MessageFlags

MSG_NOSIGNAL

Suppresses the generation of PIPE signals when writing to a socket that is no longer connected.

Although this flag is POSIX, it is not available on all platforms. Try

msgNoSignal /= mempty

in order to check whether this flag is defined on a certain platform. It is safe to just use this constant even if it might not have effect on a certain target platform. The platform independence of this flag is therefore fulfilled to some extent.

Some more explanation on the platform specific behaviour:

• Linux defines and supports MSG_NOSIGNAL and properly suppresses the generation of broken pipe-related signals.
• Windows does not define it, but does not generate signals either.
• OSX does not define it, but generates PIPE signals. The GHC runtime ignores them if you don't hook them explicitly. The non-portable socket option SO_NOSIGPIPE may be used disable signals on a per-socket basis.

It is safe and advised to always use this flag unless one wants to explictly hook and handle the PIPE signal which is not very useful in todays multi-threaded environments anyway. Although GHC's RTS ignores the signal by default it causes an unnecessary interruption.

msgEndOfRecord :: MessageFlags

Warning: Untested: Use at your own risk!

MSG_EOR

Used by SequentialPacket to mark record boundaries. Consult the POSIX standard for details.

msgOutOfBand :: MessageFlags

Warning: Untested: Use at your own risk!

MSG_OOB

Used to send and receive out-of-band data. Consult the relevant standards for details.

msgWaitAll :: MessageFlags

Warning: Untested: Use at your own risk!

MSG_WAITALL

A receive call shall not return unless the requested number of bytes becomes available.

msgPeek :: MessageFlags

MSG_PEEK

A receive shall not actually remove the received data from the input buffer.

AddressInfoFlags

data AddressInfoFlags

Use the Monoid instance to combine several flags:

mconcat [aiAddressConfig, aiV4Mapped]

Instances

Eq AddressInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

(==) :: AddressInfoFlags -> AddressInfoFlags -> Bool

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

Show AddressInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

showsPrec :: Int -> AddressInfoFlags -> ShowS

show :: AddressInfoFlags -> String

showList :: [AddressInfoFlags] -> ShowS

Semigroup AddressInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

(<>) :: AddressInfoFlags -> AddressInfoFlags -> AddressInfoFlags

sconcat :: NonEmpty AddressInfoFlags -> AddressInfoFlags

stimes :: Integral b => b -> AddressInfoFlags -> AddressInfoFlags

Monoid AddressInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

mempty :: AddressInfoFlags

mappend :: AddressInfoFlags -> AddressInfoFlags -> AddressInfoFlags

mconcat :: [AddressInfoFlags] -> AddressInfoFlags

Bits AddressInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

(.&.) :: AddressInfoFlags -> AddressInfoFlags -> AddressInfoFlags

(.|.) :: AddressInfoFlags -> AddressInfoFlags -> AddressInfoFlags

xor :: AddressInfoFlags -> AddressInfoFlags -> AddressInfoFlags

complement :: AddressInfoFlags -> AddressInfoFlags

shift :: AddressInfoFlags -> Int -> AddressInfoFlags

rotate :: AddressInfoFlags -> Int -> AddressInfoFlags

zeroBits :: AddressInfoFlags

bit :: Int -> AddressInfoFlags

setBit :: AddressInfoFlags -> Int -> AddressInfoFlags

clearBit :: AddressInfoFlags -> Int -> AddressInfoFlags

complementBit :: AddressInfoFlags -> Int -> AddressInfoFlags

testBit :: AddressInfoFlags -> Int -> Bool

bitSizeMaybe :: AddressInfoFlags -> Maybe Int

bitSize :: AddressInfoFlags -> Int

isSigned :: AddressInfoFlags -> Bool

shiftL :: AddressInfoFlags -> Int -> AddressInfoFlags

unsafeShiftL :: AddressInfoFlags -> Int -> AddressInfoFlags

shiftR :: AddressInfoFlags -> Int -> AddressInfoFlags

unsafeShiftR :: AddressInfoFlags -> Int -> AddressInfoFlags

rotateL :: AddressInfoFlags -> Int -> AddressInfoFlags

rotateR :: AddressInfoFlags -> Int -> AddressInfoFlags

popCount :: AddressInfoFlags -> Int

aiAddressConfig :: AddressInfoFlags

AI_ADDRCONFIG:

aiAll :: AddressInfoFlags

AI_ALL: Return both IPv4 (as v4-mapped IPv6 address) and IPv6 addresses when aiV4Mapped is set independent of whether IPv6 addresses exist for this name.

aiCanonicalName :: AddressInfoFlags

AI_CANONNAME:

aiNumericHost :: AddressInfoFlags

AI_NUMERICHOST:

aiNumericService :: AddressInfoFlags

AI_NUMERICSERV:

aiPassive :: AddressInfoFlags

AI_PASSIVE:

aiV4Mapped :: AddressInfoFlags

AI_V4MAPPED: Return mapped IPv4 addresses if no IPv6 addresses could be found or if aiAll flag is set.

NameInfoFlags

data NameInfoFlags

Use the Monoid instance to combine several flags:

mconcat [niNameRequired, niNoFullyQualifiedDomainName]

Instances

Eq NameInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

(==) :: NameInfoFlags -> NameInfoFlags -> Bool

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

Show NameInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

showsPrec :: Int -> NameInfoFlags -> ShowS

show :: NameInfoFlags -> String

showList :: [NameInfoFlags] -> ShowS

Semigroup NameInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

(<>) :: NameInfoFlags -> NameInfoFlags -> NameInfoFlags

sconcat :: NonEmpty NameInfoFlags -> NameInfoFlags

stimes :: Integral b => b -> NameInfoFlags -> NameInfoFlags

Monoid NameInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

mempty :: NameInfoFlags

mappend :: NameInfoFlags -> NameInfoFlags -> NameInfoFlags

mconcat :: [NameInfoFlags] -> NameInfoFlags

Bits NameInfoFlags

Defined in System.Socket.Internal.AddressInfo

Methods

(.&.) :: NameInfoFlags -> NameInfoFlags -> NameInfoFlags

(.|.) :: NameInfoFlags -> NameInfoFlags -> NameInfoFlags

xor :: NameInfoFlags -> NameInfoFlags -> NameInfoFlags

complement :: NameInfoFlags -> NameInfoFlags

shift :: NameInfoFlags -> Int -> NameInfoFlags

rotate :: NameInfoFlags -> Int -> NameInfoFlags

zeroBits :: NameInfoFlags

bit :: Int -> NameInfoFlags

setBit :: NameInfoFlags -> Int -> NameInfoFlags

clearBit :: NameInfoFlags -> Int -> NameInfoFlags

complementBit :: NameInfoFlags -> Int -> NameInfoFlags

testBit :: NameInfoFlags -> Int -> Bool

bitSizeMaybe :: NameInfoFlags -> Maybe Int

bitSize :: NameInfoFlags -> Int

isSigned :: NameInfoFlags -> Bool

shiftL :: NameInfoFlags -> Int -> NameInfoFlags

unsafeShiftL :: NameInfoFlags -> Int -> NameInfoFlags

shiftR :: NameInfoFlags -> Int -> NameInfoFlags

unsafeShiftR :: NameInfoFlags -> Int -> NameInfoFlags

rotateL :: NameInfoFlags -> Int -> NameInfoFlags

rotateR :: NameInfoFlags -> Int -> NameInfoFlags

popCount :: NameInfoFlags -> Int

niNameRequired :: NameInfoFlags

NI_NAMEREQD: Throw an exception if the hostname cannot be determined.

niDatagram :: NameInfoFlags

NI_DGRAM: Service is datagram based (i.e. UDP) rather than stream based (i.e. TCP).

niNoFullyQualifiedDomainName :: NameInfoFlags

NI_NOFQDN: Return only the hostname part of the fully qualified domain name for local hosts.

niNumericHost :: NameInfoFlags

NI_NUMERICHOST: Return the numeric form of the host address.

niNumericService :: NameInfoFlags

NI_NUMERICSERV: Return the numeric form of the service address.

Exceptions

SocketException

newtype SocketException

Contains the error code that can be matched against.

Hint: Use guards or MultiWayIf to match against specific exceptions:

if | e == eAddressInUse -> ...
   | e == eAddressNotAvailable -> ...
   | otherwise -> ...

Constructors

SocketException CInt

Instances

Eq SocketException

Defined in System.Socket.Internal.Exception

Methods

(==) :: SocketException -> SocketException -> Bool

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

Ord SocketException

Defined in System.Socket.Internal.Exception

Methods

compare :: SocketException -> SocketException -> Ordering

(<) :: SocketException -> SocketException -> Bool

(<=) :: SocketException -> SocketException -> Bool

(>) :: SocketException -> SocketException -> Bool

(>=) :: SocketException -> SocketException -> Bool

max :: SocketException -> SocketException -> SocketException

min :: SocketException -> SocketException -> SocketException

Show SocketException

Defined in System.Socket.Internal.Exception

Methods

showsPrec :: Int -> SocketException -> ShowS

show :: SocketException -> String

showList :: [SocketException] -> ShowS

Exception SocketException

Defined in System.Socket.Internal.Exception

Methods

toException :: SocketException -> SomeException

fromException :: SomeException -> Maybe SocketException

displayException :: SocketException -> String

eOk :: SocketException

No error.

eInterrupted :: SocketException

Interrupted system call.

NOTE: This exception shall not be thrown by any public operation in this library, but is handled internally.

eBadFileDescriptor :: SocketException

Bad file descriptor.

ePermissionDenied :: SocketException

Permission denied.

eInvalid :: SocketException

Invalid argument.

ePipe :: SocketException

Broken pipe.

eWouldBlock :: SocketException

Resource temporarily unavailable.

NOTE: This exception shall not be thrown by any public operation in this library, but is handled internally.

eAgain :: SocketException

Resource temporarily unavailable.

eNotSocket :: SocketException

Socket operation on non-socket.

NOTE: This should be ruled out by the type system.

eDestinationAddressRequired :: SocketException

Destination address required.

eMessageSize :: SocketException

Message too long.

eProtocolType :: SocketException

Protocol wrong type for socket.

eNoProtocolOption :: SocketException

Protocol not available.

eProtocolNotSupported :: SocketException

Protocol not supported.

eSocketTypeNotSupported :: SocketException

Socket type not supported.

eOperationNotSupported :: SocketException

Operation not supported.

eProtocolFamilyNotSupported :: SocketException

Protocol family not supported.

eAddressFamilyNotSupported :: SocketException

Address family not supported by protocol.

eAddressInUse :: SocketException

Address already in use.

eAddressNotAvailable :: SocketException

Cannot assign requested address.

eNetworkDown :: SocketException

Network is down.

eNetworkUnreachable :: SocketException

Network is unreachable.

eNetworkReset :: SocketException

Network dropped connection on reset.

eConnectionAborted :: SocketException

Software caused connection abort.

eConnectionReset :: SocketException

Connection reset by peer.

eNoBufferSpace :: SocketException

No buffer space available.

eIsConnected :: SocketException

Transport endpoint is already connected.

eNotConnected :: SocketException

Transport endpoint is not connected.

eShutdown :: SocketException

Cannot send after transport endpoint shutdown.

eTooManyReferences :: SocketException

Too many references: cannot splice.

eTimedOut :: SocketException

Connection timed out.

eConnectionRefused :: SocketException

Connection refused.

eHostDown :: SocketException

Host is down.

eHostUnreachable :: SocketException

No route to host.

eAlready :: SocketException

Operation already in progress.

NOTE: This exception shall not be thrown by any public operation in this library, but is handled internally.

eInProgress :: SocketException

Operation now in progress

AddressInfoException

newtype AddressInfoException

Contains the error code that can be matched against.

Hint: Use guards or MultiWayIf to match against specific exceptions:

if | e == eaiFail -> ...
   | e == eaiNoName -> ...
   | otherwise -> ...

Constructors

AddressInfoException CInt

Instances

Eq AddressInfoException

Defined in System.Socket.Internal.AddressInfo

Methods

(==) :: AddressInfoException -> AddressInfoException -> Bool

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

Show AddressInfoException

Defined in System.Socket.Internal.AddressInfo

Methods

showsPrec :: Int -> AddressInfoException -> ShowS

show :: AddressInfoException -> String

showList :: [AddressInfoException] -> ShowS

Exception AddressInfoException

Defined in System.Socket.Internal.AddressInfo

Methods

toException :: AddressInfoException -> SomeException

fromException :: SomeException -> Maybe AddressInfoException

displayException :: AddressInfoException -> String

eaiAgain :: AddressInfoException

AddressInfoException "Temporary failure in name resolution"

eaiBadFlags :: AddressInfoException

AddressInfoException "Bad value for ai_flags"

eaiFail :: AddressInfoException

AddressInfoException "Non-recoverable failure in name resolution"

eaiFamily :: AddressInfoException

AddressInfoException "ai_family not supported"

eaiMemory :: AddressInfoException

AddressInfoException "Memory allocation failure"

eaiNoName :: AddressInfoException

AddressInfoException "No such host is known"

eaiSocketType :: AddressInfoException

AddressInfoException "ai_socktype not supported"

eaiService :: AddressInfoException

AddressInfoException "Servname not supported for ai_socktype"

eaiSystem :: AddressInfoException

AddressInfoException "System error"