Network.Simple.TCP.TLS

This module exports simple tools for establishing TLS-secured TCP connections, relevant to both the client side and server side of the connection.

This module re-exports some functions from the Network.Simple.TCP module in the network-simple package. Consider using that module directly if you need a similar API without TLS support.

This module uses MonadIO and MonadCatch extensively so that you can reuse these functions in monads other than IO. However, if you don't care about any of that, just pretend you are using the IO monad all the time and everything will work as expected.

Server side

serve

Arguments

:: MonadIO m

=> ServerSettings

TLS settings.

-> HostPreference

Preferred host to bind.

-> ServiceName

Service port to bind.

-> ((Context, SockAddr) -> IO ())

Computation to run in a different thread once an incomming connection is accepted and a TLS-secured communication is established. Takes the TLS connection context and remote end address.

-> m ()

Start a TLS-secured TCP server that accepts incoming connections and handles each of them concurrently, in different threads.

Any acquired network resources are properly closed and discarded when done or in case of exceptions. This function binds a listening socket, accepts an incoming connection, performs a TLS handshake and then safely closes the connection when done or in case of exceptions. You don't need to perform any of those steps manually.

Listening

listen

Arguments

:: (MonadIO m, MonadCatch m)

=> HostPreference

Preferred host to bind.

-> ServiceName

Service port to bind.

-> ((Socket, SockAddr) -> m r)

Computation taking the listening socket and the address it's bound to.

-> m r

Bind a TCP listening socket and use it.

The listening socket is closed when done or in case of exceptions.

If you prefer to acquire and close the socket yourself, then use bindSock, closeSock and the listen function from Network.Socket instead.

Note: maxListenQueue is tipically 128, which is too small for high performance servers. So, we use the maximum between maxListenQueue and 2048 as the default size of the listening queue. The NoDelay and ReuseAddr options are set on the socket.

Accepting

accept

Arguments

:: (MonadIO m, MonadCatch m)

=> ServerSettings

TLS settings.

-> Socket

Listening and bound socket.

-> ((Context, SockAddr) -> m r)

Computation to run in a different thread once an incomming connection is accepted and a TLS-secured communication is established. Takes the TLS connection context and remote end address.

-> m r

Accepts a single incomming TLS-secured TCP connection and use it.

A TLS handshake is performed immediately after establishing the TCP connection and the TLS and TCP connections are properly closed when done or in case of exceptions. If you need to manage the lifetime of the connection resources yourself, then use acceptTls instead.

acceptFork

Arguments

:: MonadIO m

=> ServerSettings

TLS settings.

-> Socket

Listening and bound socket.

-> ((Context, SockAddr) -> IO ())

Computation to run in a different thread once an incomming connection is accepted and a TLS-secured communication is established. Takes the TLS connection context and remote end address.

-> m ThreadId

Like accept, except it uses a different thread to performs the TLS handshake and run the given computation.

Server TLS Settings

data ServerSettings

Abstract type representing the configuration settings for a TLS server.

Use makeServerSettings to obtain your ServerSettings value, and updateServerParams to update it.

makeServerSettings

Arguments

:: Credential

Server credential.

-> Maybe CertificateStore

CAs used to verify the client certificate. If specified, then a valid client certificate will be expected during on handshake.

-> ServerSettings

Make default ServerSettings.

The following TLS settings are used by default:

Supported versions

TLS10, TLS11, TLS12.

Supported cipher suites for TLS10

In decreasing order of preference: cipher_AES256_SHA256, cipher_AES256_SHA1, cipher_AES128_SHA256, cipher_AES128_SHA1, cipher_RC4_128_SHA1, cipher_RC4_128_MD5. The cipher suite preferred by the client is used.

Supported cipher suites for TLS11 and TLS12

In decreasing order of preference: cipher_AES256_SHA256, cipher_AES256_SHA1, cipher_AES128_SHA256, cipher_AES128_SHA1. The cipher suite preferred by the client is used.

updateServerParams :: (Params -> Params) -> ServerSettings -> ServerSettings

Update advanced TLS server configuration Params. See the Network.TLS module for details.

serverParams :: Functor f => (Params -> f Params) -> ServerSettings -> f ServerSettings

A Lens into the TLS server configuration Params. See the Network.TLS and the lens package for details.

Client side

connect

Arguments

:: (MonadIO m, MonadCatch m)

=> ClientSettings

TLS settings.

-> HostName

Server hostname.

-> ServiceName

Server service port.

-> ((Context, SockAddr) -> m r)

Computation to run after establishing TLS-secured TCP connection to the remote server. Takes the TLS connection context and remote end address.

-> m r

Connect to a TLS-secured TCP server and use the connection

A TLS handshake is performed immediately after establishing the TCP connection and the TLS and TCP connections are properly closed when done or in case of exceptions. If you need to manage the lifetime of the connection resources yourself, then use connectTls instead.

Client TLS Settings

data ClientSettings

Abstract type representing the configuration settings for a TLS client.

Use makeClientSettings or getDefaultClientSettings to obtain your ClientSettings value.

makeClientSettings

Arguments

:: [Credential]

Credentials to provide to the server, if requested. The first one is used in case we can't choose one based on information provided by the server.

-> Maybe HostName

Explicit Server Name Identification (SNI).

-> CertificateStore

CAs used to verify the server certificate. Use getSystemCertificateStore to obtain the operating system's defaults.

-> ClientSettings

Make defaults ClientSettings.

The following TLS settings are used by default:

Supported versions

TLS10, TLS11, TLS12.

Version reported during ClientHello

TLS10.

Supported cipher suites

In decreasing order of preference: cipher_AES256_SHA256, cipher_AES256_SHA1, cipher_AES128_SHA256, cipher_AES128_SHA1, cipher_RC4_128_SHA1, cipher_RC4_128_MD5.

getDefaultClientSettings :: MonadIO m => m ClientSettings

Get the system default ClientSettings.

See makeClientSettings for the for the default TLS settings used.

updateClientParams :: (Params -> Params) -> ClientSettings -> ClientSettings

Update advanced TLS client configuration Params. See the Network.TLS module for details.

clientParams :: Functor f => (Params -> f Params) -> ClientSettings -> f ClientSettings

A Lens into the TLS client configuration Params. See the Network.TLS and the lens package for details.

Credentials

data Credential

Primary certificate, private key and the rest of the certificate chain.

Constructors

Credential !X509 !PrivateKey [X509]

Instances

Show Credential

credentialToCertList :: Credential -> [(X509, Maybe PrivateKey)]

Convert client Credential to the format expected by pCertificates.

Utils

recv :: MonadIO m => Context -> m (Maybe ByteString)

Receives decrypted bytes from the given Context. Returns Nothing on EOF.

Up to 16384 decrypted bytes will be received at once. The TLS connection is automatically renegotiated if a ClientHello message is received.

send :: MonadIO m => Context -> ByteString -> m ()

Encrypts the given strict ByteString and sends it through the Context.

Low level support

useTls :: (MonadIO m, MonadCatch m) => ((Context, SockAddr) -> m a) -> (Context, SockAddr) -> m a

Perform a TLS handshake on the given Context, then perform the given action and at last gracefully close the TLS session using bye.

This function does not close the underlying TCP connection when done. Prefer to use useTlsThenClose or useTlsThenCloseFork if you need that behavior. Otherwise, you must call contextClose yourself at some point.

useTlsThenClose :: (MonadIO m, MonadCatch m) => ((Context, SockAddr) -> m a) -> (Context, SockAddr) -> m a

Like useTls, except it also fully closes the TCP connection when done.

useTlsThenCloseFork :: MonadIO m => ((Context, SockAddr) -> IO ()) -> (Context, SockAddr) -> m ThreadId

Similar to useTlsThenClose, except it performs the all the IO actions in a new thread.

Use this instead of forking useTlsThenClose yourself, as that won't give the right behavior.

connectTls

Arguments

:: MonadIO m

=> ClientSettings

TLS settings.

-> HostName

Server hostname.

-> ServiceName

Service port to bind.

-> m (Context, SockAddr)

Estalbishes a TCP connection to a remote server and returns a TLS Context configured on top of it using the given ClientSettings. The remote end address is also returned.

Prefer to use connect if you will be using the obtained Context within a limited scope.

You need to perform a TLS handshake on the resulting Context before using it for communication purposes, and gracefully close the TLS and TCP connections afterwards using. The useTls, useTlsThenClose and useTlsThenCloseFork can help you with that.

acceptTls

Arguments

:: MonadIO m

=> ServerSettings

TLS settings.

-> Socket

Listening and bound socket.

-> m (Context, SockAddr)

Accepts an incoming TCP connection and returns a TLS Context configured on top of it using the given ServerSettings. The remote end address is also returned.

Prefer to use accept if you will be using the obtained Context within a limited scope.

You need to perform a TLS handshake on the resulting Context before using it for communication purposes, and gracefully close the TLS and TCP connections afterwards using. The useTls, useTlsThenClose and useTlsThenCloseFork can help you with that.

makeClientContext :: MonadIO m => ClientSettings -> Socket -> m Context

Make a client-side TLS Context for the given settings, on top of the given TCP Socket connected to the remote end.

makeServerContext :: MonadIO m => ServerSettings -> Socket -> m Context

Make a server-side TLS Context for the given settings, on top of the given TCP Socket connected to the remote end.

Note to Windows users

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.

Exports

For your convenience, this module module also re-exports the following types from other modules:

From Network.Socket

HostName, ServiceName, Socket, SockAddr.

From Network.Simple.TCP

HostPreference(Host,HostAny,HostIPv4,HostIPv6).

From Network.TLS

Context.

module Network.Simple.TCP

module Network.Socket

module Network.TLS