Re: RPG socket not closing -- RPG400-L

i have to close the accepted socket (newsock) to terminate the
communication with the client and then the listenting socket (connection)
to stop the server from listening.

i sometimes cannot start the server after i ended it. it takes some
minutes until the network connection/listening socket is cleared up.

From: "Scott Klement" <rpg400-l@xxxxxxxxxxxxxxxx>
To: rpg400-l@xxxxxxxxxxxxxxxxxx
Date: 20.08.2019 20:40
Subject: Re: RPG socket not closing
Sent by: "RPG400-L" <rpg400-l-bounces@xxxxxxxxxxxxxxxxxx>

Franz,

Can you explain why you are closing the listener socket and then trying
to re-open it? Why not close the connection (the "accept" socket) and
keep the listener open? That is the way this is meant to be done.

It is normal for a listener to take some time to close. This is
necessary because even after you stop accepting new connections,
sometimes it is needed to be able to respond to communications for the
old connections in order to handle possible network errors and
acknowledgements properly. It typically takes about 2 minutes after you
close the listener socket before it will be available to re-use it.

Therefore, the best solution is to write your application so that it is
not necessary to close the listener and re-open it. Simply keep it
active to use for subsequent connections. If you cannot do that for
some reason, the other possible approach is to allow bind to re-use the
port with the SO_REUSEADDR socket option. This allows you to re-use the
port while the old listener is still active to handle the potential
errors and acknowledgements.

On 8/16/2019 7:17 AM, Franz.Rauscher@xxxxxxxxxxx wrote:

Hi!

i have a problem with my rpg server program.

i am followig the code from Scott Klement to wite a simple server

program.

i create a socket, bind it, listen and accept a connection. the i send a
small string and receive a small string.

after that i close the accepted socket and the original server socket

used

for bind.

But sometimes the connection stay open and the close of the socket is

not

successfull. i cannot restart the serer because the socket is already
bound.

when i do netstat *cnn i see the connection is in state time_wait and

the

listening socket is not closed.

both close calls return withaout an error so why does the os not close

the

sockets?

Grettings,
Fanz

Here is the Code:

message = 'TEST';
address = *allx'00';
address.sin_family = AF_INET;
address.sin_port = 9001;
address.sin_addr.s_addr = INADDR_ANY;

connection = socket(AF_INET:SOCK_STREAM:IPPROTO_TCP);
if bind(connection:%addr(address):%size(address) ) = -1;
rc = close(connection);
return;
endif;

if listen(connection:1 ) < 0;
rc = close(connection);
return;
endif;

newsock = accept(connection:p_address2:len);
len = send(newsock:%addr(message:*data):%size(message):0);
len = recv(newsock:%addr(ret):%size(ret):0);
rc = close(newsock);
rc1 = close(connection);
printf('message: %s %s %s <<%s>>' + x'25' : %char(rc) : %char(rc1):
%char(len): ret);