Copyright | (c) The University of Glasgow 2001 |
---|---|
License | BSD-style (see the file libraries/network/LICENSE) |
Maintainer | libraries@haskell.org |
Stability | provisional |
Portability | portable |
Safe Haskell | None |
Language | Haskell2010 |
This is the main module of the network package supposed to be used with either Network.Socket.ByteString or Network.Socket.ByteString.Lazy for sending/receiving.
Here are two minimal example programs using the TCP/IP protocol: a server that echoes all data that it receives back (servicing only one client) and a client using it.
-- Echo server program module Main (main) where import Control.Concurrent (forkFinally) import qualified Control.Exception as E import Control.Monad (unless, forever, void) import qualified Data.ByteString as S import Network.Socket import Network.Socket.ByteString (recv, sendAll) main :: IO () main = withSocketsDo $ do addr <- resolve "3000" E.bracket (open addr) close loop where resolve port = do let hints = defaultHints { addrFlags = [AI_PASSIVE] , addrSocketType = Stream } addr:_ <- getAddrInfo (Just hints) Nothing (Just port) return addr open addr = do sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr) setSocketOption sock ReuseAddr 1 -- If the prefork technique is not used, -- set CloseOnExec for the security reasons. fd <- fdSocket sock setCloseOnExecIfNeeded fd bind sock (addrAddress addr) listen sock 10 return sock loop sock = forever $ do (conn, peer) <- accept sock putStrLn $ "Connection from " ++ show peer void $ forkFinally (talk conn) (\_ -> close conn) talk conn = do msg <- recv conn 1024 unless (S.null msg) $ do sendAll conn msg talk conn
{-# LANGUAGE OverloadedStrings #-} -- Echo client program module Main (main) where import qualified Control.Exception as E import qualified Data.ByteString.Char8 as C import Network.Socket import Network.Socket.ByteString (recv, sendAll) main :: IO () main = withSocketsDo $ do addr <- resolve "127.0.0.1" "3000" E.bracket (open addr) close talk where resolve host port = do let hints = defaultHints { addrSocketType = Stream } addr:_ <- getAddrInfo (Just hints) (Just host) (Just port) return addr open addr = do sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr) connect sock $ addrAddress addr return sock talk sock = do sendAll sock "Hello, world!" msg <- recv sock 1024 putStr "Received: " C.putStrLn msg
The proper programming model is that one Socket
is handled by
a single thread. If multiple threads use one Socket
concurrently,
unexpected things would happen. There is one exception for multiple
threads vs a single Socket
: one thread reads data from a Socket
only and the other thread writes data to the Socket
only.
Synopsis
- withSocketsDo :: IO a -> IO a
- getAddrInfo :: Maybe AddrInfo -> Maybe HostName -> Maybe ServiceName -> IO [AddrInfo]
- type HostName = String
- type ServiceName = String
- data AddrInfo = AddrInfo {}
- defaultHints :: AddrInfo
- data AddrInfoFlag
- addrInfoFlagImplemented :: AddrInfoFlag -> Bool
- connect :: Socket -> SockAddr -> IO ()
- bind :: Socket -> SockAddr -> IO ()
- listen :: Socket -> Int -> IO ()
- accept :: Socket -> IO (Socket, SockAddr)
- close :: Socket -> IO ()
- close' :: Socket -> IO ()
- shutdown :: Socket -> ShutdownCmd -> IO ()
- data ShutdownCmd
- data SocketOption
- isSupportedSocketOption :: SocketOption -> Bool
- getSocketOption :: Socket -> SocketOption -> IO Int
- setSocketOption :: Socket -> SocketOption -> Int -> IO ()
- data Socket
- socket :: Family -> SocketType -> ProtocolNumber -> IO Socket
- fdSocket :: Socket -> IO CInt
- mkSocket :: CInt -> IO Socket
- socketToHandle :: Socket -> IOMode -> IO Handle
- data SocketType
- isSupportedSocketType :: SocketType -> Bool
- getSocketType :: Socket -> IO SocketType
- data Family
- = AF_UNSPEC
- | AF_UNIX
- | AF_INET
- | AF_INET6
- | AF_IMPLINK
- | AF_PUP
- | AF_CHAOS
- | AF_NS
- | AF_NBS
- | AF_ECMA
- | AF_DATAKIT
- | AF_CCITT
- | AF_SNA
- | AF_DECnet
- | AF_DLI
- | AF_LAT
- | AF_HYLINK
- | AF_APPLETALK
- | AF_ROUTE
- | AF_NETBIOS
- | AF_NIT
- | AF_802
- | AF_ISO
- | AF_OSI
- | AF_NETMAN
- | AF_X25
- | AF_AX25
- | AF_OSINET
- | AF_GOSSIP
- | AF_IPX
- | Pseudo_AF_XTP
- | AF_CTF
- | AF_WAN
- | AF_SDL
- | AF_NETWARE
- | AF_NDD
- | AF_INTF
- | AF_COIP
- | AF_CNT
- | Pseudo_AF_RTIP
- | Pseudo_AF_PIP
- | AF_SIP
- | AF_ISDN
- | Pseudo_AF_KEY
- | AF_NATM
- | AF_ARP
- | Pseudo_AF_HDRCMPLT
- | AF_ENCAP
- | AF_LINK
- | AF_RAW
- | AF_RIF
- | AF_NETROM
- | AF_BRIDGE
- | AF_ATMPVC
- | AF_ROSE
- | AF_NETBEUI
- | AF_SECURITY
- | AF_PACKET
- | AF_ASH
- | AF_ECONET
- | AF_ATMSVC
- | AF_IRDA
- | AF_PPPOX
- | AF_WANPIPE
- | AF_BLUETOOTH
- | AF_CAN
- isSupportedFamily :: Family -> Bool
- packFamily :: Family -> CInt
- unpackFamily :: CInt -> Family
- type ProtocolNumber = CInt
- defaultProtocol :: ProtocolNumber
- data SockAddr
- isSupportedSockAddr :: SockAddr -> Bool
- getPeerName :: Socket -> IO SockAddr
- getSocketName :: Socket -> IO SockAddr
- type HostAddress = Word32
- hostAddressToTuple :: HostAddress -> (Word8, Word8, Word8, Word8)
- tupleToHostAddress :: (Word8, Word8, Word8, Word8) -> HostAddress
- type HostAddress6 = (Word32, Word32, Word32, Word32)
- hostAddress6ToTuple :: HostAddress6 -> (Word16, Word16, Word16, Word16, Word16, Word16, Word16, Word16)
- tupleToHostAddress6 :: (Word16, Word16, Word16, Word16, Word16, Word16, Word16, Word16) -> HostAddress6
- type FlowInfo = Word32
- type ScopeID = Word32
- ifNameToIndex :: String -> IO (Maybe Int)
- ifIndexToName :: Int -> IO (Maybe String)
- data PortNumber
- defaultPort :: PortNumber
- socketPortSafe :: Socket -> IO (Maybe PortNumber)
- socketPort :: Socket -> IO PortNumber
- isUnixDomainSocketAvailable :: Bool
- socketPair :: Family -> SocketType -> ProtocolNumber -> IO (Socket, Socket)
- sendFd :: Socket -> CInt -> IO ()
- recvFd :: Socket -> IO CInt
- getPeerCredential :: Socket -> IO (Maybe CUInt, Maybe CUInt, Maybe CUInt)
- getNameInfo :: [NameInfoFlag] -> Bool -> Bool -> SockAddr -> IO (Maybe HostName, Maybe ServiceName)
- data NameInfoFlag
- setCloseOnExecIfNeeded :: CInt -> IO ()
- getCloseOnExec :: CInt -> IO Bool
- setNonBlockIfNeeded :: CInt -> IO ()
- getNonBlock :: CInt -> IO Bool
- sendBuf :: Socket -> Ptr Word8 -> Int -> IO Int
- recvBuf :: Socket -> Ptr Word8 -> Int -> IO Int
- sendBufTo :: Socket -> Ptr a -> Int -> SockAddr -> IO Int
- recvBufFrom :: Socket -> Ptr a -> Int -> IO (Int, SockAddr)
- maxListenQueue :: Int
Initialisation
withSocketsDo :: IO a -> IO a Source #
With older versions of the network
library (version 2.6.0.2 or earlier)
on Windows operating systems,
the networking subsystem must be initialised using withSocketsDo
before
any networking operations can be used. eg.
main = withSocketsDo $ do {...}
It is fine to nest calls to withSocketsDo
, and to perform networking operations
after withSocketsDo
has returned.
withSocketsDo
is not necessary for the current network library.
However, for compatibility with older versions on Windows, it is good practice
to always call withSocketsDo
(it's very cheap).
Address information
:: 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
bind
.
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:
>>>
let hints = defaultHints { addrFlags = [AI_NUMERICHOST], addrSocketType = Stream }
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.
>>>
addr:_ <- getAddrInfo (Just hints) (Just "127.0.0.1") (Just "http")
>>>
addrAddress addr
127.0.0.1:80
Types
type HostName = String Source #
Either a host name e.g., "haskell.org"
or a numeric host
address string consisting of a dotted decimal IPv4 address or an
IPv6 address e.g., "192.168.0.1"
.
type ServiceName = String Source #
Either a service name e.g., "http"
or a numeric port number.
Instances
Eq AddrInfo Source # | |
Show AddrInfo Source # | |
Storable AddrInfo Source # | |
Defined in Network.Socket.Info |
defaultHints :: AddrInfo Source #
Default hints for address lookup with getAddrInfo
. The values
of the addrAddress
and addrCanonName
fields are undefined
,
and are never inspected by getAddrInfo
.
>>>
addrFlags defaultHints
[]>>>
addrFamily defaultHints
AF_UNSPEC>>>
addrSocketType defaultHints
NoSocketType>>>
addrProtocol defaultHints
0
Flags
data AddrInfoFlag Source #
Flags that control the querying behaviour of getAddrInfo
.
For more information, see https://tools.ietf.org/html/rfc3493#page-25
AI_ADDRCONFIG | The list of returned |
AI_ALL | If |
AI_CANONNAME | The |
AI_NUMERICHOST | The |
AI_NUMERICSERV | The |
AI_PASSIVE | If no |
AI_V4MAPPED | If an IPv6 lookup is performed, and no IPv6 addresses are found, IPv6-mapped IPv4 addresses will be returned. (Only some platforms support this.) |
Instances
Eq AddrInfoFlag Source # | |
Defined in Network.Socket.Info (==) :: AddrInfoFlag -> AddrInfoFlag -> Bool # (/=) :: AddrInfoFlag -> AddrInfoFlag -> Bool # | |
Read AddrInfoFlag Source # | |
Defined in Network.Socket.Info readsPrec :: Int -> ReadS AddrInfoFlag # readList :: ReadS [AddrInfoFlag] # | |
Show AddrInfoFlag Source # | |
Defined in Network.Socket.Info showsPrec :: Int -> AddrInfoFlag -> ShowS # show :: AddrInfoFlag -> String # showList :: [AddrInfoFlag] -> ShowS # |
addrInfoFlagImplemented :: AddrInfoFlag -> Bool Source #
Indicate whether the given AddrInfoFlag
will have any effect on
this system.
Socket operations
bind :: Socket -> SockAddr -> IO () Source #
Bind the socket to an address. The socket must not already be
bound. The Family
passed to bind
must be the
same as that passed to socket
. If the special port number
defaultPort
is passed then the system assigns the next available
use port.
listen :: Socket -> Int -> IO () Source #
Listen for connections made to the socket. The second argument specifies the maximum number of queued connections and should be at least 1; the maximum value is system-dependent (usually 5).
accept :: Socket -> IO (Socket, SockAddr) Source #
Accept a connection. The socket must be bound to an address and
listening for connections. The return value is a pair (conn,
address)
where conn
is a new socket object usable to send and
receive data on the connection, and address
is the address bound
to the socket on the other end of the connection.
On Unix, FD_CLOEXEC is set to the new Socket
.
Closing
close' :: Socket -> IO () Source #
Close the socket. This function throws exceptions if the underlying system call returns errors.
shutdown :: Socket -> ShutdownCmd -> IO () Source #
Shut down one or both halves of the connection, depending on the
second argument to the function. If the second argument is
ShutdownReceive
, further receives are disallowed. If it is
ShutdownSend
, further sends are disallowed. If it is
ShutdownBoth
, further sends and receives are disallowed.
Socket options
data SocketOption Source #
Socket options for use with setSocketOption
and getSocketOption
.
The existence of a constructor does not imply that the relevant option
is supported on your system: see isSupportedSocketOption
Debug | SO_DEBUG |
ReuseAddr | SO_REUSEADDR |
Type | SO_TYPE |
SoError | SO_ERROR |
DontRoute | SO_DONTROUTE |
Broadcast | SO_BROADCAST |
SendBuffer | SO_SNDBUF |
RecvBuffer | SO_RCVBUF |
KeepAlive | SO_KEEPALIVE |
OOBInline | SO_OOBINLINE |
TimeToLive | IP_TTL |
MaxSegment | TCP_MAXSEG |
NoDelay | TCP_NODELAY |
Cork | TCP_CORK |
Linger | SO_LINGER: timeout in seconds, 0 means disabling/disabled. |
ReusePort | SO_REUSEPORT |
RecvLowWater | SO_RCVLOWAT |
SendLowWater | SO_SNDLOWAT |
RecvTimeOut | SO_RCVTIMEO: this does not work at this moment. |
SendTimeOut | SO_SNDTIMEO: this does not work at this moment. |
UseLoopBack | SO_USELOOPBACK |
UserTimeout | TCP_USER_TIMEOUT |
IPv6Only | IPV6_V6ONLY: don't use this on OpenBSD. |
CustomSockOpt (CInt, CInt) |
Instances
Show SocketOption Source # | |
Defined in Network.Socket.Options showsPrec :: Int -> SocketOption -> ShowS # show :: SocketOption -> String # showList :: [SocketOption] -> ShowS # |
isSupportedSocketOption :: SocketOption -> Bool Source #
Does the SocketOption
exist on this system?
getSocketOption :: Socket -> SocketOption -> IO Int Source #
Get a socket option that gives an Int value. There is currently no API to get e.g. the timeval socket options
setSocketOption :: Socket -> SocketOption -> Int -> IO () Source #
Set a socket option that expects an Int value. There is currently no API to set e.g. the timeval socket options
Socket
Basic type for a socket.
socket :: Family -> SocketType -> ProtocolNumber -> IO Socket Source #
Create a new socket using the given address family, socket type
and protocol number. The address family is usually AF_INET
,
AF_INET6
, or AF_UNIX
. The socket type is usually Stream
or
Datagram
. The protocol number is usually defaultProtocol
.
If AF_INET6
is used and the socket type is Stream
or Datagram
,
the IPv6Only
socket option is set to 0 so that both IPv4 and IPv6
can be handled with one socket.
>>>
import Network.Socket
>>>
let hints = defaultHints { addrFlags = [AI_NUMERICHOST, AI_NUMERICSERV], addrSocketType = Stream }
>>>
addr:_ <- getAddrInfo (Just hints) (Just "127.0.0.1") (Just "5000")
>>>
sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
>>>
Network.Socket.bind sock (addrAddress addr)
>>>
getSocketName sock
127.0.0.1:5000
fdSocket :: Socket -> IO CInt Source #
Getting a file descriptor from a socket.
If a Socket
is shared with multiple threads and
one uses fdSocket
, unexpected issues may happen.
Consider the following scenario:
1) Thread A acquires a Fd
from Socket
by fdSocket
.
2) Thread B close the Socket
.
3) Thread C opens a new Socket
. Unfortunately it gets the same Fd
number which thread A is holding.
In this case, it is safer for Thread A to clone Fd
by
dup
. But this would still suffer from
a rase condition between fdSocket
and close
.
socketToHandle :: Socket -> IOMode -> IO Handle Source #
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
.
Types of Socket
data SocketType Source #
Socket Types.
The existence of a constructor does not necessarily imply that that
socket type is supported on your system: see isSupportedSocketType
.
NoSocketType | 0, used in getAddrInfo hints, for example |
Stream | SOCK_STREAM |
Datagram | SOCK_DGRAM |
Raw | SOCK_RAW |
RDM | SOCK_RDM |
SeqPacket | SOCK_SEQPACKET |
Instances
Eq SocketType Source # | |
Defined in Network.Socket.Types (==) :: SocketType -> SocketType -> Bool # (/=) :: SocketType -> SocketType -> Bool # | |
Ord SocketType Source # | |
Defined in Network.Socket.Types compare :: SocketType -> SocketType -> Ordering # (<) :: SocketType -> SocketType -> Bool # (<=) :: SocketType -> SocketType -> Bool # (>) :: SocketType -> SocketType -> Bool # (>=) :: SocketType -> SocketType -> Bool # max :: SocketType -> SocketType -> SocketType # min :: SocketType -> SocketType -> SocketType # | |
Read SocketType Source # | |
Defined in Network.Socket.Types readsPrec :: Int -> ReadS SocketType # readList :: ReadS [SocketType] # readPrec :: ReadPrec SocketType # readListPrec :: ReadPrec [SocketType] # | |
Show SocketType Source # | |
Defined in Network.Socket.Types showsPrec :: Int -> SocketType -> ShowS # show :: SocketType -> String # showList :: [SocketType] -> ShowS # |
isSupportedSocketType :: SocketType -> Bool Source #
Does the SOCK_ constant corresponding to the given SocketType exist on this system?
getSocketType :: Socket -> IO SocketType Source #
Get the SocketType
of an active socket.
Since: 3.0.1.0
Family
Address families.
A constructor being present here does not mean it is supported by the
operating system: see isSupportedFamily
.
AF_UNSPEC | unspecified |
AF_UNIX | UNIX-domain |
AF_INET | Internet Protocol version 4 |
AF_INET6 | Internet Protocol version 6 |
AF_IMPLINK | Arpanet imp addresses |
AF_PUP | pup protocols: e.g. BSP |
AF_CHAOS | mit CHAOS protocols |
AF_NS | XEROX NS protocols |
AF_NBS | nbs protocols |
AF_ECMA | european computer manufacturers |
AF_DATAKIT | datakit protocols |
AF_CCITT | CCITT protocols, X.25 etc |
AF_SNA | IBM SNA |
AF_DECnet | DECnet |
AF_DLI | Direct data link interface |
AF_LAT | LAT |
AF_HYLINK | NSC Hyperchannel |
AF_APPLETALK | Apple Talk |
AF_ROUTE | Internal Routing Protocol (aka AF_NETLINK) |
AF_NETBIOS | NetBios-style addresses |
AF_NIT | Network Interface Tap |
AF_802 | IEEE 802.2, also ISO 8802 |
AF_ISO | ISO protocols |
AF_OSI | umbrella of all families used by OSI |
AF_NETMAN | DNA Network Management |
AF_X25 | CCITT X.25 |
AF_AX25 | AX25 |
AF_OSINET | AFI |
AF_GOSSIP | US Government OSI |
AF_IPX | Novell Internet Protocol |
Pseudo_AF_XTP | eXpress Transfer Protocol (no AF) |
AF_CTF | Common Trace Facility |
AF_WAN | Wide Area Network protocols |
AF_SDL | SGI Data Link for DLPI |
AF_NETWARE | Netware |
AF_NDD | NDD |
AF_INTF | Debugging use only |
AF_COIP | connection-oriented IP, aka ST II |
AF_CNT | Computer Network Technology |
Pseudo_AF_RTIP | Help Identify RTIP packets |
Pseudo_AF_PIP | Help Identify PIP packets |
AF_SIP | Simple Internet Protocol |
AF_ISDN | Integrated Services Digital Network |
Pseudo_AF_KEY | Internal key-management function |
AF_NATM | native ATM access |
AF_ARP | ARP (RFC 826) |
Pseudo_AF_HDRCMPLT | Used by BPF to not rewrite hdrs in iface output |
AF_ENCAP | ENCAP |
AF_LINK | Link layer interface |
AF_RAW | Link layer interface |
AF_RIF | raw interface |
AF_NETROM | Amateur radio NetROM |
AF_BRIDGE | multiprotocol bridge |
AF_ATMPVC | ATM PVCs |
AF_ROSE | Amateur Radio X.25 PLP |
AF_NETBEUI | Netbeui 802.2LLC |
AF_SECURITY | Security callback pseudo AF |
AF_PACKET | Packet family |
AF_ASH | Ash |
AF_ECONET | Acorn Econet |
AF_ATMSVC | ATM SVCs |
AF_IRDA | IRDA sockets |
AF_PPPOX | PPPoX sockets |
AF_WANPIPE | Wanpipe API sockets |
AF_BLUETOOTH | bluetooth sockets |
AF_CAN | Controller Area Network |
isSupportedFamily :: Family -> Bool Source #
Does the AF_ constant corresponding to the given family exist on this system?
Protocol number
type ProtocolNumber = CInt Source #
Protocl number.
defaultProtocol :: ProtocolNumber Source #
This is the default protocol for a given service.
>>>
defaultProtocol
0
Basic socket address type
Socket addresses.
The existence of a constructor does not necessarily imply that
that socket address type is supported on your system: see
isSupportedSockAddr
.
SockAddrInet !PortNumber !HostAddress | |
SockAddrInet6 !PortNumber !FlowInfo !HostAddress6 !ScopeID | |
SockAddrUnix String |
|
isSupportedSockAddr :: SockAddr -> Bool Source #
Is the socket address type supported on this system?
Host address
type HostAddress = Word32 Source #
The raw network byte order number is read using host byte order.
Therefore on little-endian architectures the byte order is swapped. For
example 127.0.0.1
is represented as 0x0100007f
on little-endian hosts
and as 0x7f000001
on big-endian hosts.
For direct manipulation prefer hostAddressToTuple
and
tupleToHostAddress
.
hostAddressToTuple :: HostAddress -> (Word8, Word8, Word8, Word8) Source #
Converts HostAddress
to representation-independent IPv4 quadruple.
For example for 127.0.0.1
the function will return (0x7f, 0, 0, 1)
regardless of host endianness.
tupleToHostAddress :: (Word8, Word8, Word8, Word8) -> HostAddress Source #
Converts IPv4 quadruple to HostAddress
.
Host address6
type HostAddress6 = (Word32, Word32, Word32, Word32) Source #
Independent of endianness. For example ::1
is stored as (0, 0, 0, 1)
.
For direct manipulation prefer hostAddress6ToTuple
and
tupleToHostAddress6
.
hostAddress6ToTuple :: HostAddress6 -> (Word16, Word16, Word16, Word16, Word16, Word16, Word16, Word16) Source #
Converts HostAddress6
to representation-independent IPv6 octuple.
tupleToHostAddress6 :: (Word16, Word16, Word16, Word16, Word16, Word16, Word16, Word16) -> HostAddress6 Source #
Converts IPv6 octuple to HostAddress6
.
Flow Info
Scope ID
ifNameToIndex :: String -> IO (Maybe Int) Source #
Returns the index corresponding to the interface name.
Since 2.7.0.0.
ifIndexToName :: Int -> IO (Maybe String) Source #
Returns the interface name corresponding to the index.
Since 2.7.0.0.
Port number
data PortNumber Source #
Port number.
Use the Num
instance (i.e. use a literal) to create a
PortNumber
value.
>>>
1 :: PortNumber
1>>>
read "1" :: PortNumber
1>>>
show (12345 :: PortNumber)
"12345">>>
50000 < (51000 :: PortNumber)
True>>>
50000 < (52000 :: PortNumber)
True>>>
50000 + (10000 :: PortNumber)
60000
Instances
defaultPort :: PortNumber Source #
Default port number.
>>>
defaultPort
0
socketPortSafe :: Socket -> IO (Maybe PortNumber) Source #
Getting the port of socket.
socketPort :: Socket -> IO PortNumber Source #
Getting the port of socket.
IOError
is thrown if a port is not available.
UNIX-domain socket
isUnixDomainSocketAvailable :: Bool Source #
Whether or not UNIX-domain sockets are available.
Since 2.7.0.0.
socketPair :: Family -> SocketType -> ProtocolNumber -> IO (Socket, Socket) Source #
Build a pair of connected socket objects.
For portability, use this function in the case
where isUnixDomainSocketAvailable
is True
and specify AF_UNIX
to the first argument.
sendFd :: Socket -> CInt -> IO () Source #
Send a file descriptor over a UNIX-domain socket.
Use this function in the case where isUnixDomainSocketAvailable
is
True
.
recvFd :: Socket -> IO CInt Source #
Receive a file descriptor over a UNIX-domain socket. Note that the resulting
file descriptor may have to be put into non-blocking mode in order to be
used safely. See setNonBlockIfNeeded
.
Use this function in the case where isUnixDomainSocketAvailable
is
True
.
getPeerCredential :: Socket -> IO (Maybe CUInt, Maybe CUInt, Maybe CUInt) Source #
Getting process ID, user ID and group ID for UNIX-domain sockets.
This is implemented with SO_PEERCRED on Linux and getpeereid()
on BSD variants. Unfortunately, on some BSD variants
getpeereid() returns unexpected results, rather than an error,
for AF_INET sockets. It is the user's responsibility to make sure
that the socket is a UNIX-domain socket.
Also, on some BSD variants, getpeereid() does not return credentials
for sockets created via socketPair
, only separately created and then
explicitly connected UNIX-domain sockets work on such systems.
Since 2.7.0.0.
Name information
:: [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.
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.
>>>
addr:_ <- getAddrInfo (Just defaultHints) (Just "127.0.0.1") (Just "http")
>>>
getNameInfo [NI_NUMERICHOST, NI_NUMERICSERV] True True $ addrAddress addr
(Just "127.0.0.1",Just "80")
data NameInfoFlag Source #
Flags that control the querying behaviour of getNameInfo
.
For more information, see https://tools.ietf.org/html/rfc3493#page-30
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. |
NI_NAMEREQD | If the hostname cannot be looked up, an IO error is thrown. |
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. |
Instances
Eq NameInfoFlag Source # | |
Defined in Network.Socket.Info (==) :: NameInfoFlag -> NameInfoFlag -> Bool # (/=) :: NameInfoFlag -> NameInfoFlag -> Bool # | |
Read NameInfoFlag Source # | |
Defined in Network.Socket.Info readsPrec :: Int -> ReadS NameInfoFlag # readList :: ReadS [NameInfoFlag] # | |
Show NameInfoFlag Source # | |
Defined in Network.Socket.Info showsPrec :: Int -> NameInfoFlag -> ShowS # show :: NameInfoFlag -> String # showList :: [NameInfoFlag] -> ShowS # |
Low level
socket operations
setCloseOnExecIfNeeded :: CInt -> IO () Source #
Set the close_on_exec flag on Unix. On Windows, nothing is done.
Since 2.7.0.0.
getCloseOnExec :: CInt -> IO Bool Source #
Get the close_on_exec flag.
On Windows, this function always returns False
.
Since 2.7.0.0.
setNonBlockIfNeeded :: CInt -> IO () Source #
Set the nonblocking flag on Unix. On Windows, nothing is done.
getNonBlock :: CInt -> IO Bool Source #
Get the nonblocking flag.
On Windows, this function always returns False
.
Since 2.7.0.0.
Sending and receiving data
sendBuf :: Socket -> Ptr Word8 -> Int -> IO Int Source #
Send data to the socket. The socket must be connected to a remote socket. Returns the number of bytes sent. Applications are responsible for ensuring that all data has been sent.
recvBuf :: Socket -> Ptr Word8 -> Int -> IO Int Source #
Receive data from the socket. The socket must be in a connected state. This function may return fewer bytes than specified. If the message is longer than the specified length, it may be discarded depending on the type of socket. This function may block until a message arrives.
Considering hardware and network realities, the maximum number of bytes to receive should be a small power of 2, e.g., 4096.
The return value is the length of received data. Zero means EOF. Historical note: Version 2.8.x.y or earlier, an EOF error was thrown. This was changed in version 3.0.
sendBufTo :: Socket -> Ptr a -> Int -> SockAddr -> IO Int Source #
Send data to the socket. The recipient can be specified explicitly, so the socket need not be in a connected state. Returns the number of bytes sent. Applications are responsible for ensuring that all data has been sent.
recvBufFrom :: Socket -> Ptr a -> Int -> IO (Int, SockAddr) Source #
Receive data from the socket, writing it into buffer instead of
creating a new string. The socket need not be in a connected
state. Returns (nbytes, address)
where nbytes
is the number of
bytes received and address
is a SockAddr
representing the
address of the sending socket.
If the first return value is zero, it means EOF.
For Stream
sockets, the second return value would be invalid.
NOTE: blocking on Windows unless you compile with -threaded (see GHC ticket #1129)
Special constants
maxListenQueue :: Int Source #
This is the value of SOMAXCONN, typically 128. 128 is good enough for normal network servers but is too small for high performance servers.