Mailing List Archive: setsockopt, SO

setsockopt, SO_REUSEADDR question

May 26, 1999, 3:25 PM

Post #1 of 3 (6130 views)

Hello people,
pardon me if this has been answered before, couldn't find any trails.
I have the following code:

addr = '127.0.0.1', 5050
srv = SocketServer.ThreadingTCPServer(addr, handle_con)
srv.socket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
srv.serve_forever()

Everything is working as expected, except for the fact that the
setsockopt does not do what i'd like it to. I understand it's
highly possible I've passed wrong arguments but could not find
any help on the right ones. What I want it to do is to be able to
start a server on port 5050, even if another server was just shut
down and there's still a closing listen socket there. Since it does
not work, I have to wait about 30 sec between each run of my
program.
Any advice, please?

Thank you,
Costas

--
Constantinos A. Kotsokalis || c.kotsokalis@noc.ntua.gr
National Technical University of Athens
Network Management Center
Tel. No: +30 1 7721861

setsockopt, SO_REUSEADDR question [ In reply to ]

meowing at banet

May 26, 1999, 8:17 PM

Post #2 of 3 (6041 views)

Permalink

Constantinos A Kotsokalis <c.kotsokalis@noc.ntua.gr> writes:

> Hello people,
> pardon me if this has been answered before, couldn't find any trails.
> I have the following code:
{...}
> srv.socket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
> srv.serve_forever()
{so far, so good}
> What I want it to do is to be able to start a server on port 5050,
> even if another server was just shut down and there's still a
> closing listen socket there. Since it does not work, I have to
> wait about 30 sec between each run of my program.

Are you making sure to shutdown() _all_ your sockets when you are done
with them, including on error conditions? It matters.

setsockopt, SO_REUSEADDR question [ In reply to ]

sjturner at ix

May 27, 1999, 7:21 AM

Post #3 of 3 (6054 views)

Permalink

Constantinos A. Kotsokalis wrote:
>
> Hello people,
> pardon me if this has been answered before, couldn't find any trails.
> I have the following code:
>
> addr = '127.0.0.1', 5050
> srv = SocketServer.ThreadingTCPServer(addr, handle_con)
> srv.socket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
> srv.serve_forever()
>
> Everything is working as expected, except for the fact that the
> setsockopt does not do what i'd like it to. I understand it's
> highly possible I've passed wrong arguments but could not find
> any help on the right ones. What I want it to do is to be able to
> start a server on port 5050, even if another server was just shut
> down and there's still a closing listen socket there. Since it does
> not work, I have to wait about 30 sec between each run of my
> program.
> Any advice, please?
>
> Thank you,
> Costas

The problem is that the SO_REUSEADDR socket option must be set before
the address is bound to the socket. This can be done by subclassing
ThreadingTCPServer and overriding the server_bind method as follows:

import SocketServer, socket
class MyThreadingTCPServer(SocketServer.ThreadingTCPServer):
def server_bind(self):
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.socket.bind(self.server_address)

Regards,
Stephen

--
Stephen J. Turner <sjturner@ix.netcom.com>