{-# LANGUAGE DeriveDataTypeable #-}

{-# LANGUAGE ViewPatterns #-}

-- |

-- Module      : Network.Socks5

-- License     : BSD-style

-- Maintainer  : Vincent Hanquez <vincent@snarc.org>

-- Stability   : experimental

-- Portability : unknown

--

-- This is an implementation of SOCKS5 as defined in RFC 1928

--

-- In Wikipedia's words:

--

--   SOCKet Secure (SOCKS) is an Internet protocol that routes network packets

--   between a client and server through a proxy server. SOCKS5 additionally

--   provides authentication so only authorized users may access a server.

--   Practically, a SOCKS server will proxy TCP connections to an arbitrary IP

--   address as well as providing a means for UDP packets to be forwarded.

--

-- BIND and UDP ASSOCIATE messages are not implemented.

-- However main usage of SOCKS is covered in this implementation.

--

module Network.Socks5

    (

    -- * Types

      SocksAddress(..)

    , SocksHostAddress(..)

    , SocksReply(..)

    , SocksError(..)

    -- * Configuration

    , module Network.Socks5.Conf

    -- * Methods

    , socksConnectWithSocket

    , socksConnect

    -- * Variants

    , socksConnectAddr

    , socksConnectName

    , socksConnectTo'

    , socksConnectTo

    , socksConnectWith

    ) where

import Control.Monad

import Control.Exception

import qualified Data.ByteString.Char8 as BC

import Network.Socket ( close, Socket, SocketType(..), SockAddr(..), Family(..)

                      , socket, socketToHandle, connect)

import Network.BSD

import Network (PortID(..))

import qualified Network.Socks5.Command as Cmd

import Network.Socks5.Conf

import Network.Socks5.Types

import Network.Socks5.Lowlevel

import System.IO

-- | connect a user specified new socket to the socks server,

-- and connect the stream on the server side to the 'SockAddress' specified.

--

-- |socket|-----sockServer----->|server|----destAddr----->|destination|

--

socksConnectWithSocket :: Socket       -- ^ Socket to use.

                       -> SocksConf    -- ^ SOCKS configuration for the server.

                       -> SocksAddress -- ^ SOCKS Address to connect to.

                       -> IO (SocksHostAddress, PortNumber)

socksConnectWithSocket sock serverConf destAddr = do

    serverAddr <- resolveToSockAddr (socksServer serverConf)

    connect sock serverAddr

    r <- Cmd.establish sock [SocksMethodNone]

    when (r == SocksMethodNotAcceptable) $ error "cannot connect with no socks method of authentication"

    Cmd.rpc_ sock (Connect destAddr)

-- | connect a new socket to a socks server and connect the stream on the

-- server side to the 'SocksAddress' specified.

socksConnect :: SocksConf    -- ^ SOCKS configuration for the server.

             -> SocksAddress -- ^ SOCKS Address to connect to.

             -> IO (Socket, (SocksHostAddress, PortNumber))

socksConnect serverConf destAddr =

    getProtocolNumber "tcp" >>= \proto ->

    bracketOnError (socket AF_INET Stream proto) close $ \sock -> do

        ret <- socksConnectWithSocket sock serverConf destAddr

        return (sock, ret)

-- | connect a new socket to the socks server, and connect the stream on the server side

-- to the sockaddr specified. the sockaddr need to be SockAddrInet or SockAddrInet6.

--

-- a unix sockaddr will raises an exception.

--

-- |socket|-----sockServer----->|server|----destAddr----->|destination|

{-# DEPRECATED socksConnectAddr "use socksConnectWithSocket" #-}

socksConnectAddr :: Socket -> SockAddr -> SockAddr -> IO ()

socksConnectAddr sock sockserver destaddr =

    socksConnectWithSocket sock

                           (defaultSocksConfFromSockAddr sockserver)

                           (socksServer $ defaultSocksConfFromSockAddr destaddr) >>

    return ()

-- | connect a new socket to the socks server, and connect the stream to a FQDN

-- resolved on the server side.

socksConnectName :: Socket -> SockAddr -> String -> PortNumber -> IO ()

socksConnectName sock sockserver destination port = do

    socksConnectWithSocket sock

                           (defaultSocksConfFromSockAddr sockserver)

                           (SocksAddress (SocksAddrDomainName $ BC.pack destination) port)

    >> return ()

-- | create a new socket and connect in to a destination through the specified

-- SOCKS configuration.

socksConnectWith :: SocksConf -- ^ SOCKS configuration

                 -> String    -- ^ destination hostname

                 -> PortID    -- ^ destination port

                 -> IO Socket

socksConnectWith socksConf desthost destport = do

    dport <- resolvePortID destport

    proto <- getProtocolNumber "tcp"

    bracketOnError (socket AF_INET Stream proto) close $ \sock -> do

        sockaddr <- resolveToSockAddr (socksServer socksConf)

        socksConnectName sock sockaddr desthost dport

        return sock

-- | similar to Network connectTo but use a socks proxy with default socks configuration.

socksConnectTo' :: String -> PortID -> String -> PortID -> IO Socket

socksConnectTo' sockshost socksport desthost destport = do

    sport <- resolvePortID socksport

    let socksConf = defaultSocksConf sockshost sport

    socksConnectWith socksConf desthost destport

-- | similar to Network connectTo but use a socks proxy with default socks configuration.

socksConnectTo :: String -> PortID -> String -> PortID -> IO Handle

socksConnectTo sockshost socksport desthost destport = do

    sport <- resolvePortID socksport

    let socksConf = defaultSocksConf sockshost sport

    sock <- socksConnectWith socksConf desthost destport

    socketToHandle sock ReadWriteMode

resolvePortID (Service serv) = getServicePortNumber serv

resolvePortID (PortNumber n) = return n

resolvePortID _              = error "unsupported unix PortID"