[Haskell-cafe] Receiving UDP messages on Windows 7

[Edward Amsden]

Turns out it is the firewall, which is odd because I told Windows to
allow it when it popped up the firewall dialog. Turning off the
firewall for that interface fixed the issue.

On Mon, Jun 18, 2012 at 11:14 AM, Holger Reinhardt <hreinhardt at gmail.com> wrote:
> Hi,
>
> I added the following code to your program:
>
>
> import qualified Data.ByteString.Char8 as B
>
> sendMsg = withSocketsDo $ do
>     sock <- socket AF_INET Datagram defaultProtocol
>     target <- inet_addr "192.168.2.103" -- put your servers IP here
>     sendTo sock (B.pack "TEST") $ SockAddrInet 5555 target
>
>
> On my Windows 7 machine this works fine; the messages are received by the
> server. It also works if I run the sendMsg program on a Linux VM which lives
> on a separate IP.
> So it seems that it's not a general bug but rather a problem with your
> setup, possibly a firewall.
>
> 2012/6/18 Edward Amsden <eca7215 at cs.rit.edu>
>>
>> Hi all,
>>
>> I have the following program, which I'm running using runghc 7.4.1
>> with HP2012.2 on Windows 7:
>>
>> ==
>> {-# LANGUAGE OverloadedStrings #-}
>> module Main where
>>
>> import Network.Socket hiding (send, sendTo, recv, recvFrom)
>> import Network.Socket.ByteString
>> import qualified Data.Text as T
>> import qualified Data.Text.Encoding as T
>> import qualified Data.Text.IO as T
>>
>> port :: String
>> port = show (5555 :: Int)
>>
>> main :: IO ()
>> main = withSocketsDo $ do
>>  addrInf:_ <- fmap (filter ((== AF_INET) . addrFamily)) $ getAddrInfo
>> (Just (defaultHints {addrFlags = [AI_PASSIVE]})) Nothing (Just port)
>>  putStrLn "Address info: "
>>  print addrInf
>>  sock <- socket (addrFamily addrInf) Datagram defaultProtocol
>>  putStrLn "Socket created"
>>  bindSocket sock (addrAddress addrInf)
>>  putStrLn "Socket bound"
>>  let procMessages =
>>        do
>>          (msg, addr) <- recvFrom sock 1024
>>          let addrTxt = T.pack $ show addr
>>              msgTxt  = T.decodeUtf8 msg
>>              outputTxt = T.concat [addrTxt, " says ", msgTxt]
>>          T.putStrLn outputTxt
>>        procMessages
>>  procMessages
>> ==
>>
>> I'm trying to receive incoming UDP packets on port 5555.
>> Unfortunately, when I run the program it does not receive packets. It
>> prints the address info, and the messages that the socket has been
>> created and bound. When I run Wireshark I can see that there are
>> indeed incoming UDP packets arriving on port 5555 (from another
>> computer on the local network running a proprietary program).
>>
>> The other bit of information that may be useful is that the machine
>> has 2 network interfaces. However, when I replace the Nothing
>> parameter of getAddrInfo with
>> (Just "192.168.1.3") which is the address of the correct NIC, the
>> behavior is as before.
>>
>> Is there something I'm missing?
>>
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>
>



-- 
Edward Amsden
Student
Computer Science
Rochester Institute of Technology
www.edwardamsden.com