Portability | portable |
---|---|
Stability | provisional |
Maintainer | libraries@haskell.org |
Network.Socket
Contents
Description
The Network.Socket module is for when you want full control over sockets. Essentially the entire C socket API is exposed through this module; in general the operations follow the behaviour of the C functions of the same name (consult your favourite Unix networking book).
A higher level interface to networking operations is provided through the module Network.
- data Socket = MkSocket CInt Family SocketType ProtocolNumber (MVar SocketStatus)
- data Family
- data SocketType
- data SockAddr
- data SocketStatus
- = NotConnected
- | Bound
- | Listening
- | Connected
- | ConvertedToHandle
- | Closed
- type HostAddress = Word32
- type HostAddress6 = (Word32, Word32, Word32, Word32)
- type FlowInfo = Word32
- type ScopeID = Word32
- data ShutdownCmd
- type ProtocolNumber = CInt
- defaultProtocol :: ProtocolNumber
- newtype PortNumber = PortNum Word16
- type HostName = String
- type ServiceName = String
- data AddrInfo = AddrInfo {
- addrFlags :: [AddrInfoFlag]
- addrFamily :: Family
- addrSocketType :: SocketType
- addrProtocol :: ProtocolNumber
- addrAddress :: SockAddr
- addrCanonName :: Maybe String
- data AddrInfoFlag
- = AI_ADDRCONFIG
- | AI_ALL
- | AI_CANONNAME
- | AI_NUMERICHOST
- | AI_NUMERICSERV
- | AI_PASSIVE
- | AI_V4MAPPED
- addrInfoFlagImplemented :: AddrInfoFlag -> Bool
- defaultHints :: AddrInfo
- getAddrInfo :: Maybe AddrInfo -> Maybe HostName -> Maybe ServiceName -> IO [AddrInfo]
- data NameInfoFlag
- = NI_DGRAM
- | NI_NAMEREQD
- | NI_NOFQDN
- | NI_NUMERICHOST
- | NI_NUMERICSERV
- getNameInfo :: [NameInfoFlag] -> Bool -> Bool -> SockAddr -> IO (Maybe HostName, Maybe ServiceName)
- socket :: Family -> SocketType -> ProtocolNumber -> IO Socket
- socketPair :: Family -> SocketType -> ProtocolNumber -> IO (Socket, Socket)
- connect :: Socket -> SockAddr -> IO ()
- bindSocket :: Socket -> SockAddr -> IO ()
- listen :: Socket -> Int -> IO ()
- accept :: Socket -> IO (Socket, SockAddr)
- getPeerName :: Socket -> IO SockAddr
- getSocketName :: Socket -> IO SockAddr
- getPeerCred :: Socket -> IO (CUInt, CUInt, CUInt)
- socketPort :: Socket -> IO PortNumber
- socketToHandle :: Socket -> IOMode -> IO Handle
- sendTo :: Socket -> String -> SockAddr -> IO Int
- sendBufTo :: Socket -> Ptr a -> Int -> SockAddr -> IO Int
- recvFrom :: Socket -> Int -> IO (String, Int, SockAddr)
- recvBufFrom :: Socket -> Ptr a -> Int -> IO (Int, SockAddr)
- send :: Socket -> String -> IO Int
- recv :: Socket -> Int -> IO String
- recvLen :: Socket -> Int -> IO (String, Int)
- inet_addr :: String -> IO HostAddress
- inet_ntoa :: HostAddress -> IO String
- shutdown :: Socket -> ShutdownCmd -> IO ()
- sClose :: Socket -> IO ()
- sIsConnected :: Socket -> IO Bool
- sIsBound :: Socket -> IO Bool
- sIsListening :: Socket -> IO Bool
- sIsReadable :: Socket -> IO Bool
- sIsWritable :: Socket -> IO Bool
- data SocketOption
- = DummySocketOption__
- | Debug
- | ReuseAddr
- | Type
- | SoError
- | DontRoute
- | Broadcast
- | SendBuffer
- | RecvBuffer
- | KeepAlive
- | OOBInline
- | TimeToLive
- | MaxSegment
- | NoDelay
- | Linger
- | RecvLowWater
- | SendLowWater
- | RecvTimeOut
- | SendTimeOut
- getSocketOption :: Socket -> SocketOption -> IO Int
- setSocketOption :: Socket -> SocketOption -> Int -> IO ()
- sendFd :: Socket -> CInt -> IO ()
- recvFd :: Socket -> IO CInt
- sendAncillary :: Socket -> Int -> Int -> Int -> Ptr a -> Int -> IO ()
- recvAncillary :: Socket -> Int -> Int -> IO (Int, Int, Ptr a, Int)
- aNY_PORT :: PortNumber
- iNADDR_ANY :: HostAddress
- iN6ADDR_ANY :: HostAddress6
- sOMAXCONN :: Int
- sOL_SOCKET :: Int
- sCM_RIGHTS :: Int
- maxListenQueue :: Int
- withSocketsDo :: IO a -> IO a
- fdSocket :: Socket -> CInt
- mkSocket :: CInt -> Family -> SocketType -> ProtocolNumber -> SocketStatus -> IO Socket
- packFamily :: Family -> CInt
- unpackFamily :: CInt -> Family
- packSocketType :: SocketType -> CInt
- throwSocketErrorIfMinus1_ :: Num a => String -> IO a -> IO ()
Types
data Socket
Constructors
MkSocket CInt Family SocketType ProtocolNumber (MVar SocketStatus) |
data Family
This data type might have different constructors depending on what is supported by the operating system.
data SocketType
Socket Types.
This data type might have different constructors depending on what is supported by the operating system.
Instances
Eq SocketType | |
Ord SocketType | |
Read SocketType | |
Show SocketType | |
Typeable SocketType |
data SockAddr
Constructors
SockAddrInet PortNumber HostAddress | |
SockAddrInet6 PortNumber FlowInfo HostAddress6 ScopeID | |
SockAddrUnix String |
data SocketStatus
Constructors
NotConnected | |
Bound | |
Listening | |
Connected | |
ConvertedToHandle | |
Closed |
Instances
Eq SocketStatus | |
Show SocketStatus | |
Typeable SocketStatus |
type HostAddress = Word32
type HostAddress6 = (Word32, Word32, Word32, Word32)
type FlowInfo = Word32
type ScopeID = Word32
data ShutdownCmd
Constructors
ShutdownReceive | |
ShutdownSend | |
ShutdownBoth |
Instances
Typeable ShutdownCmd |
type ProtocolNumber = CInt
defaultProtocol :: ProtocolNumber
This is the default protocol for a given service.
newtype PortNumber
Constructors
PortNum Word16 |
Instances
Enum PortNumber | |
Eq PortNumber | |
Integral PortNumber | |
Num PortNumber | |
Ord PortNumber | |
Real PortNumber | |
Show PortNumber | |
Typeable PortNumber | |
Storable PortNumber |
Address operations
type HostName = String
type ServiceName = String
data AddrInfo
Constructors
AddrInfo | |
Fields
|
data AddrInfoFlag
Flags that control the querying behaviour of getAddrInfo
.
Instances
Eq AddrInfoFlag | |
Read AddrInfoFlag | |
Show AddrInfoFlag | |
Typeable AddrInfoFlag |
addrInfoFlagImplemented :: AddrInfoFlag -> Bool
Indicate whether the given AddrInfoFlag
will have any effect on
this system.
Default hints for address lookup with getAddrInfo
. The values
of the addrAddress
and addrCanonName
fields are undefined
,
and are never inspected by getAddrInfo
.
Arguments
:: Maybe AddrInfo | preferred socket type or protocol |
-> Maybe HostName | host name to look up |
-> Maybe ServiceName | service name to look up |
-> IO [AddrInfo] | resolved addresses, with best first |
Resolve a host or service name to one or more addresses.
The AddrInfo
values that this function returns contain SockAddr
values that you can pass directly to connect
or
bindSocket
.
This function is protocol independent. It can return both IPv4 and IPv6 address information.
The AddrInfo
argument specifies the preferred query behaviour,
socket options, or protocol. You can override these conveniently
using Haskell's record update syntax on defaultHints
, for example
as follows:
myHints = defaultHints { addrFlags = [AI_ADDRCONFIG, AI_CANONNAME] }
Values for addrFlags
control query behaviour. The supported
flags are as follows:
AI_PASSIVE
- If no
HostName
value is provided, the network address in eachSockAddr
will be left as a wild card, i.e. as eitheriNADDR_ANY
oriN6ADDR_ANY
. This is useful for server applications that will accept connections from any client. AI_CANONNAME
- The
addrCanonName
field of the first returnedAddrInfo
will contain the canonical name of the host. AI_NUMERICHOST
- The
HostName
argument must be a numeric address in string form, and network name lookups will not be attempted.
Note: Although the following flags are required by RFC 3493, they
may not have an effect on all platforms, because the underlying
network stack may not support them. To see whether a flag from the
list below will have any effect, call addrInfoFlagImplemented
.
AI_NUMERICSERV
- The
ServiceName
argument must be a port number in string form, and service name lookups will not be attempted. AI_ADDRCONFIG
- The list of returned
AddrInfo
values will only contain IPv4 addresses if the local system has at least one IPv4 interface configured, and likewise for IPv6. AI_V4MAPPED
- If an IPv6 lookup is performed, and no IPv6 addresses are found, IPv6-mapped IPv4 addresses will be returned.
AI_ALL
- If
AI_ALL
is specified, return all matching IPv6 and IPv4 addresses. Otherwise, this flag has no effect.
You must provide a Just
value for at least one of the HostName
or ServiceName
arguments. HostName
can be either a numeric
network address (dotted quad for IPv4, colon-separated hex for
IPv6) or a hostname. In the latter case, its addresses will be
looked up unless AI_NUMERICHOST
is specified as a hint. If you
do not provide a HostName
value and do not set AI_PASSIVE
as
a hint, network addresses in the result will contain the address of
the loopback interface.
If the query fails, this function throws an IO exception instead of
returning an empty list. Otherwise, it returns a non-empty list
of AddrInfo
values.
There are several reasons why a query might result in several values. For example, the queried-for host could be multihomed, or the service might be available via several protocols.
Note: the order of arguments is slightly different to that defined
for getaddrinfo
in RFC 2553. The AddrInfo
parameter comes first
to make partial application easier.
Example:
let hints = defaultHints { addrFlags = [AI_ADDRCONFIG, AI_CANONNAME] }
addrs <- getAddrInfo (Just hints) (Just www.haskell.org) (Just http)
let addr = head addrs
sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
connect sock (addrAddress addr)
data NameInfoFlag
Constructors
NI_DGRAM | |
NI_NAMEREQD | |
NI_NOFQDN | |
NI_NUMERICHOST | |
NI_NUMERICSERV |
Instances
Eq NameInfoFlag | |
Read NameInfoFlag | |
Show NameInfoFlag | |
Typeable NameInfoFlag |
Arguments
:: [NameInfoFlag] | flags to control lookup behaviour |
-> Bool | whether to look up a hostname |
-> Bool | whether to look up a service name |
-> SockAddr | the address to look up |
-> IO (Maybe HostName, Maybe ServiceName) |
Resolve an address to a host or service name. This function is protocol independent.
The list of NameInfoFlag
values controls query behaviour. The
supported flags are as follows:
NI_NOFQDN
- If a host is local, return only the hostname part of the FQDN.
NI_NUMERICHOST
- The name of the host is not looked up. Instead, a numeric representation of the host's address is returned. For an IPv4 address, this will be a dotted-quad string. For IPv6, it will be colon-separated hexadecimal.
NI_NUMERICSERV
- The name of the service is not looked up. Instead, a numeric representation of the service is returned.
NI_NAMEREQD
- If the hostname cannot be looked up, an IO error is thrown.
NI_DGRAM
- Resolve a datagram-based service name. This is required only for the few protocols that have different port numbers for their datagram-based versions than for their stream-based versions.
Hostname and service name lookups can be expensive. You can
specify which lookups to perform via the two Bool
arguments. If
one of these is False
, the corresponding value in the returned
tuple will be Nothing
, and no lookup will be performed.
If a host or service's name cannot be looked up, then the numeric form of the address or service will be returned.
If the query fails, this function throws an IO exception.
Example:
(hostName, _) <- getNameInfo [] True False myAddress
Socket Operations
socket :: Family -> SocketType -> ProtocolNumber -> IO Socket
socketPair :: Family -> SocketType -> ProtocolNumber -> IO (Socket, Socket)
bindSocket :: Socket -> SockAddr -> IO ()
getPeerName :: Socket -> IO SockAddr
getSocketName :: Socket -> IO SockAddr
getPeerCred :: Socket -> IO (CUInt, CUInt, CUInt)
Returns the processID, userID and groupID of the socket's peer.
Only available on platforms that support SO_PEERCRED on domain sockets.
socketPort :: Socket -> IO PortNumber
socketToHandle :: Socket -> IOMode -> IO Handle
turns a Socket into an Handle
. By default, the new handle is
unbuffered. Use hSetBuffering
to change the buffering.
Note that since a Handle
is automatically closed by a finalizer
when it is no longer referenced, you should avoid doing any more
operations on the Socket
after calling socketToHandle
. To
close the Socket
after socketToHandle
, call hClose
on the Handle
.
sendTo :: Socket -> String -> SockAddr -> IO Int
NOTE: blocking on Windows unless you compile with -threaded (see GHC ticket #1129)
recvFrom :: Socket -> Int -> IO (String, Int, SockAddr)
NOTE: blocking on Windows unless you compile with -threaded (see GHC ticket #1129)
recvBufFrom :: Socket -> Ptr a -> Int -> IO (Int, SockAddr)
inet_addr :: String -> IO HostAddress
inet_ntoa :: HostAddress -> IO String
shutdown :: Socket -> ShutdownCmd -> IO ()
Predicates on sockets
sIsConnected :: Socket -> IO Bool
sIsListening :: Socket -> IO Bool
sIsReadable :: Socket -> IO Bool
sIsWritable :: Socket -> IO Bool
Socket options
data SocketOption
Constructors
DummySocketOption__ | |
Debug | |
ReuseAddr | |
Type | |
SoError | |
DontRoute | |
Broadcast | |
SendBuffer | |
RecvBuffer | |
KeepAlive | |
OOBInline | |
TimeToLive | |
MaxSegment | |
NoDelay | |
Linger | |
RecvLowWater | |
SendLowWater | |
RecvTimeOut | |
SendTimeOut |
Instances
Typeable SocketOption |
getSocketOption :: Socket -> SocketOption -> IO Int
setSocketOption :: Socket -> SocketOption -> Int -> IO ()
File descriptor transmission
sendAncillary :: Socket -> Int -> Int -> Int -> Ptr a -> Int -> IO ()
recvAncillary :: Socket -> Int -> Int -> IO (Int, Int, Ptr a, Int)
Special Constants
The IPv4 wild card address.
The IPv6 wild card address.
sOMAXCONN :: Int
sOL_SOCKET :: Int
sCM_RIGHTS :: Int
maxListenQueue :: Int
Initialisation
withSocketsDo :: IO a -> IO a
On Windows operating systems, the networking subsystem has to be
initialised using withSocketsDo
before any networking operations can
be used. eg.
main = withSocketsDo $ do {...}
Although this is only strictly necessary on Windows platforms, it is harmless on other platforms, so for portability it is good practice to use it all the time.
Very low level operations
mkSocket :: CInt -> Family -> SocketType -> ProtocolNumber -> SocketStatus -> IO Socket
Internal
The following are exported ONLY for use in the BSD module and should not be used anywhere else.
packFamily :: Family -> CInt
unpackFamily :: CInt -> Family
packSocketType :: SocketType -> CInt
Arguments
:: Num a | |
=> String | textual description of the location |
-> IO a | the |
-> IO () |
Throw an IOError
corresponding to the current socket error if
the IO action returns a result of -1
. Discards the result of the
IO action after error handling.