sending data on a socket followed by a close

sending data on a socket followed by a close

[Lee Chin]

Hi,
I am trying to send 500K on a asynchronous socket and after I've written all my data, I want to close the socket.

So I send data in a loop, and between calls to "write" I select on the filedescriptor till it is writable again and send more data.

I continue this untill I have no more data to send.

At the end, after sending all my data, I "close" the socket.

However, the client sees a TCP RST packet and only receives partial data.

What am I doing wrong?  I though that the close would actually kill the socket after all the data has been sent

Thanks
Lee
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Re: sending data on a socket followed by a close

[David S. Miller]

On Wed, 27 Aug 2003 19:35:52 -0500
"Lee Chin" <leechin@mail.com> wrote:

> At the end, after sending all my data, I "close" the socket.
> 
> However, the client sees a TCP RST packet and only receives partial data.
> 
> What am I doing wrong?  I though that the close would actually kill the socket after all the data has been sent

You cannot close() the socket until you have emptied all
the data bytes on the read side of the socket(), if data
remains on the read side when you close() a TCP RST packet
is sent.
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Re: sending data on a socket followed by a close

[Nagendra Singh Tomar]

Receiver (in ur discussion) should be sending the RST not the sender.
But ur explaination seems to hint that the sender of data is the one 
sending RST. 

tomar

On Thu, 28 Aug 2003, David S. Miller wrote:

> On Wed, 27 Aug 2003 19:35:52 -0500
> "Lee Chin" <leechin@mail.com> wrote:
> 
> > At the end, after sending all my data, I "close" the socket.
> > 
> > However, the client sees a TCP RST packet and only receives partial
> data.
> > 
> > What am I doing wrong?  I though that the close would actually kill
> the socket after all the data has been sent
> 
> You cannot close() the socket until you have emptied all
> the data bytes on the read side of the socket(), if data
> remains on the read side when you close() a TCP RST packet
> is sent.
> -
> To unsubscribe from this list: send the line "unsubscribe linux-net" in
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> 

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Re: sending data on a socket followed by a close

[Stephen Samuel]

Rather than using close, try calling shutdown (2)...
(dunno if it will work).

If that doesn't work, then use the socket option  SO_LINGER

SO_LINGER     When enabled, a close(2) or shutdown(2) will  not  return
               until all  queued  messages for the socket have been
               successfully sent or the linger timeout has  been  reached.
               Otherwise,  the  call returns  immediately  and the closing
               is done in the background.

man 7 socket
   for more info

Lee Chin wrote:
> Hi,
> I am trying to send 500K on a asynchronous socket and after I've written all my data, I want to close the socket.
> 
> So I send data in a loop, and between calls to "write" I select on the filedescriptor till it is writable again and send more data.
> 
> I continue this untill I have no more data to send.
> 
> At the end, after sending all my data, I "close" the socket.
> 
> However, the client sees a TCP RST packet and only receives partial data.
> 
> What am I doing wrong?  I though that the close would actually kill the socket after all the data has been sent
> 
> Thanks
> Lee


-- 
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		   http://www.bcgreen.com/~samuel/
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Re: sending data on a socket followed by a close

[Marco Cova]

Il giorno Thu, Aug 28, 2003 at 10:03:14PM -0700, pare che Stephen Samuel abbia scritto:
> Rather than using close, try calling shutdown (2)...
> (dunno if it will work).
> 
> If that doesn't work, then use the socket option  SO_LINGER
> 
> SO_LINGER     When enabled, a close(2) or shutdown(2) will  not  return
>               until all  queued  messages for the socket have been
>               successfully sent or the linger timeout has  been  reached.
>               Otherwise,  the  call returns  immediately  and the closing
>               is done in the background.
> 
> man 7 socket
>   for more info
> 
> Lee Chin wrote:
> >Hi,
> >I am trying to send 500K on a asynchronous socket and after I've written 
> >all my data, I want to close the socket.
> >
> >So I send data in a loop, and between calls to "write" I select on the 
> >filedescriptor till it is writable again and send more data.
> >
> >I continue this untill I have no more data to send.
> >
> >At the end, after sending all my data, I "close" the socket.
> >
> >However, the client sees a TCP RST packet and only receives partial data.
> >
> >What am I doing wrong?  I though that the close would actually kill the 
> >socket after all the data has been sent

RST on close is what you get if you set the SO_LINGER option for the
socket with l_onoff = 1 and l_linger = 0 (and the socket reference
count has dropped to 0).

You can find a complete description of the different choices you have for
closing a connection in Stevens, "UNIX Network Programming", pag
187-191.

HTH,
Marco

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