RE: [U2][UV] Forcing a port to close
If you've always used the flag, then CLOSE_WAIT makes no difference. However, if you see a LOT of connections in CLOSE_WAIT on your service port, then you should check your code. Something is definitely not kosher with your child processes. I don't have a problem in my code. My email was simply to back up the recommendation to use SO_REUSEADDR, given to Nick. Thanks James --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2][UV] Forcing a port to close
This is exactly what I am getting. The process is stopped, but for whatever reason, UniVerse is not closing and cleaning up the port. The program in question has LOGTO statements in it, and I think that it is causing itself to get crossed up on the socket port. If I include the following statement, will it help: X = setSocketOptions(SOCKETHANDLE, REUSEADDR : @VM : 1) Thanks, Nick Cipollina -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Glen B Sent: Thursday, February 24, 2005 6:13 PM To: u2-users@listserver.u2ug.org Subject: RE: [U2][UV] Forcing a port to close This is a typical socket address condition that can't be safely overridden by hand. If you look at your net stats, the socket in question is probably in a CLOSE_WAIT state. This is a subsystem status that says the remote has shutdown and it's waiting for the socket to close and cleanup. If the socket gets dumped improperly by the socket application, then the socket can be left in CLOSE_WAIT with no process attached to finish cleanup. The status will clear up, but it could take a long time. That all depends on the tcp_close_wait setup and whether or not the socket is setup with the SO_LINGER flag. If the socket's SO_REUSEADDR flag can be enabled using some kind of U2 setsocketopt function before you listen on it, then you can re-use the same socket address over and over again. Check out this sockets FAQ: http://www.unixguide.net/network/socketfaq/ Glen http://picksource.com http://mvdevcentral.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Nick Cipollina Sent: Thursday, February 24, 2005 4:20 PM To: u2-users@listserver.u2ug.org Subject: [U2][UV] Forcing a port to close Is anyone aware of a way to force a socket port to close at the operating system level. We are currently using Sun 9.xx. We have a process that opens a port and accepts socket connections. Whenever we stop it and try to restart it, we get a port in use message. The only way that I've been able to get it to release the port is to stop and start universe again. I'm just wondering if there is a way to force the port to close. Thanks. Nick Cipollina Pick Programmer ACS - Heritage Information Systems, Inc. 2810 North Parham Road, Suite 210 Richmond, VA 23294 (804)644-8707 x 314 --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2][UV] Forcing a port to close
Nick, I looked this up in the socket guide and the syntax is correct. The only real issue that can arise by enabling address re-use is the slim possibility that partial data could be received into the socket buffer, from the sockets that were never shutdown down properly. This can lead to confusion in the application and/or the socket subsystem. I've never had that issue occur, but the possibility of the condition should be known. Just for clarity in future reading, socket shutdown and close are not synonymous. Close refers only to the release of a file handle. A handle can be closed and re-opened on the same socket address. Shutdown refers to the releasing of the file handle and also the addresses used by the socket. Glen http://picksource.com http://mvdevcentral.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Nick Cipollina Sent: Friday, February 25, 2005 8:29 AM To: u2-users@listserver.u2ug.org Subject: RE: [U2][UV] Forcing a port to close This is exactly what I am getting. The process is stopped, but for whatever reason, UniVerse is not closing and cleaning up the port. The program in question has LOGTO statements in it, and I think that it is causing itself to get crossed up on the socket port. If I include the following statement, will it help: X = setSocketOptions(SOCKETHANDLE, REUSEADDR : @VM : 1) Thanks, Nick Cipollina -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Glen B Sent: Thursday, February 24, 2005 6:13 PM To: u2-users@listserver.u2ug.org Subject: RE: [U2][UV] Forcing a port to close This is a typical socket address condition that can't be safely overridden by hand. If you look at your net stats, the socket in question is probably in a CLOSE_WAIT state. This is a subsystem status that says the remote has shutdown and it's waiting for the socket to close and cleanup. If the socket gets dumped improperly by the socket application, then the socket can be left in CLOSE_WAIT with no process attached to finish cleanup. The status will clear up, but it could take a long time. That all depends on the tcp_close_wait setup and whether or not the socket is setup with the SO_LINGER flag. If the socket's SO_REUSEADDR flag can be enabled using some kind of U2 setsocketopt function before you listen on it, then you can re-use the same socket address over and over again. Check out this sockets FAQ: http://www.unixguide.net/network/socketfaq/ Glen http://picksource.com http://mvdevcentral.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Nick Cipollina Sent: Thursday, February 24, 2005 4:20 PM To: u2-users@listserver.u2ug.org Subject: [U2][UV] Forcing a port to close Is anyone aware of a way to force a socket port to close at the operating system level. We are currently using Sun 9.xx. We have a process that opens a port and accepts socket connections. Whenever we stop it and try to restart it, we get a port in use message. The only way that I've been able to get it to release the port is to stop and start universe again. I'm just wondering if there is a way to force the port to close. Thanks. Nick Cipollina Pick Programmer ACS - Heritage Information Systems, Inc. 2810 North Parham Road, Suite 210 Richmond, VA 23294 (804)644-8707 x 314 --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2][UV] Forcing a port to close
setting option SO_REUSEADDR, has a number of uses, one being that if the listening gciserver is killed and there are still live connections, a new server can be started. Without this option the system will return error address already in use. This condition is typically encountered as follows: a) a listening server is started b) a connection request arrives and a child process is spawned to handle that client c) the listening server terminates but the child continues to service the client on the existing connection d) then an attempt is made to restart the listening server (will fail with address already in use due to client connection) SO_REUSEADDR also allows two listening servers to be started for the same port no, but specifying different ip addresses (if hosts has mulitple addresses). However we can still only start one server for each ip address available to the machine I have never heard of the shutdown issue mentioned below. I have been writing socket applications for a long time and use SO_REUSEADDR and have never come across this issue. There are some other uses for RO_REUSEADDR which are quite advanced. Reason why close my not shutdown a socket. If a parent process and child process have a socket handle open. In the case of the parent forgetting to do a close on the socket handle after an accept call, then there will be two references to the same socket. When the close is called by the child then the open reference counter on the socket will be decremented but the socket will not be shutdown (as the parent still has it open). The socket will only be shutdown if the parent closes the socket too. This is a common mistake. However if the code is corrected and the parent does close the socket, then when the child calls close on the socket, there is only one reference count to the socket then a close will shutdown the socket too. James -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Glen B Sent: 25 February 2005 14:28 To: u2-users@listserver.u2ug.org Subject: RE: [U2][UV] Forcing a port to close Nick, I looked this up in the socket guide and the syntax is correct. The only real issue that can arise by enabling address re-use is the slim possibility that partial data could be received into the socket buffer, from the sockets that were never shutdown down properly. This can lead to confusion in the application and/or the socket subsystem. I've never had that issue occur, but the possibility of the condition should be known. Just for clarity in future reading, socket shutdown and close are not synonymous. Close refers only to the release of a file handle. A handle can be closed and re-opened on the same socket address. Shutdown refers to the releasing of the file handle and also the addresses used by the socket. Glen http://picksource.com http://mvdevcentral.com --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2][UV] Forcing a port to close
In my last message gciserver in the first line should have read simply server. James Sungard --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2][UV] Forcing a port to close
-Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Friday, February 25, 2005 11:32 AM To: u2-users@listserver.u2ug.org Subject: RE: [U2][UV] Forcing a port to close setting option SO_REUSEADDR, has a number of uses, one being that if the listening gciserver is killed and there are still live connections, a new server can be started. Without this option the system will return error address already in use. This condition is typically encountered as follows: a) a listening server is started b) a connection request arrives and a child process is spawned to handle that client c) the listening server terminates but the child continues to service the client on the existing connection d) then an attempt is made to restart the listening server (will fail with address already in use due to client connection) SO_REUSEADDR also allows two listening servers to be started for the same port no, but specifying different ip addresses (if hosts has mulitple addresses). However we can still only start one server for each ip address available to the machine This is true. I have never heard of the shutdown issue mentioned below. I have been writing socket applications for a long time and use SO_REUSEADDR and have never come across this issue. Shutdown(in my terms) refers to the bi-directional termination of a TCP connection, not just the release of a socket handle. You can also shutdown() a socket, but that only partially closes the socket. shutdown() blocks recv() functionality, while still allowing send(). This is a great method of connection controlling that a lot of coders overlook. I didn't see it listed in the U2 sockets API, but it is available under most programming languages. If you've always used the flag, then CLOSE_WAIT makes no difference. However, if you see a LOT of connections in CLOSE_WAIT on your service port, then you should check your code. Something is definitely not kosher with your child processes. There are some other uses for RO_REUSEADDR which are quite advanced. Reason why close my not shutdown a socket. If a parent process and child process have a socket handle open. In the case of the parent forgetting to do a close on the socket handle after an accept call, then there will be two references to the same socket. When the close is called by the child then the open reference counter on the socket will be decremented but the socket will not be shutdown (as the parent still has it open). The socket will only be shutdown if the parent closes the socket too. This is a common mistake. However if the code is corrected and the parent does close the socket, then when the child calls close on the socket, there is only one reference count to the socket then a close will shutdown the socket too. This also happens when a parent is killed by an interrupt and there is no interrupt handling in the application. The parent bails without cleaning up and then waiting for the children to follow suit. Every child process gets set to CLOSE_WAIT. We are on the same page, but I think I'm writing it in a different language. :P James Glen http://picksource.com http://mvdevcentral.com --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2][UV] Forcing a port to close
quote who=Nick Cipollina Is anyone aware of a way to force a socket port to close at the operating system level. We are currently using Sun 9.xx. We have a process that opens a port and accepts socket connections. Whenever we stop it and try to restart it, we get a port in use message. The only way that I've been able to get it to release the port is to stop and start universe again. I'm just wondering if there is a way to force the port to close. Thanks. I'm not sure this will help, but in Linux there's the /proc filesystem. In that filesystem there's a file that represents everything that's going on. Whenever I have a similar problem, I use fuser -k /proc/whatever/file and that essentially 'closes' the process. Karl Nick Cipollina Pick Programmer ACS - Heritage Information Systems, Inc. 2810 North Parham Road, Suite 210 Richmond, VA 23294 (804)644-8707 x 314 --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ -- Karl L. Pearson Director of IT, ATS Industrial Supply Direct: 801-978-4429 Toll-free: 800-789-9300 1,29 Fax: 801-972-3888 http://www.atsindustrial.com [EMAIL PROTECTED] --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2][UV] Forcing a port to close
[EMAIL PROTECTED] wrote: I'm not sure this will help, but in Linux there's the /proc filesystem. In that filesystem there's a file that represents everything that's going on. Whenever I have a similar problem, I use fuser -k /proc/whatever/file and that essentially 'closes' the process. Karl You can also reference the port directly with fuser. This should work for other unixes in addition to linux. For example, fuser -k telnet/tcp would kill all the telnet daemon processes, fuser -k 5100/upd would kill whatever's listening on udp port 5100. The default fuser kill signal is SIGKILL (9), which might not be the most desirable way to terminate the process. On linux you can specify a different kill signal (like 15) with the fuser -signal option. On unix you might want to use fuser to determine the process ID, then use kill to get rid of it. -John -- John Hester System Network Administrator Momentum Group Inc. (949) 833-8886 x623 http://memosamples.com --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2][UV] Forcing a port to close
This is a typical socket address condition that can't be safely overridden by hand. If you look at your net stats, the socket in question is probably in a CLOSE_WAIT state. This is a subsystem status that says the remote has shutdown and it's waiting for the socket to close and cleanup. If the socket gets dumped improperly by the socket application, then the socket can be left in CLOSE_WAIT with no process attached to finish cleanup. The status will clear up, but it could take a long time. That all depends on the tcp_close_wait setup and whether or not the socket is setup with the SO_LINGER flag. If the socket's SO_REUSEADDR flag can be enabled using some kind of U2 setsocketopt function before you listen on it, then you can re-use the same socket address over and over again. Check out this sockets FAQ: http://www.unixguide.net/network/socketfaq/ Glen http://picksource.com http://mvdevcentral.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Nick Cipollina Sent: Thursday, February 24, 2005 4:20 PM To: u2-users@listserver.u2ug.org Subject: [U2][UV] Forcing a port to close Is anyone aware of a way to force a socket port to close at the operating system level. We are currently using Sun 9.xx. We have a process that opens a port and accepts socket connections. Whenever we stop it and try to restart it, we get a port in use message. The only way that I've been able to get it to release the port is to stop and start universe again. I'm just wondering if there is a way to force the port to close. Thanks. Nick Cipollina Pick Programmer ACS - Heritage Information Systems, Inc. 2810 North Parham Road, Suite 210 Richmond, VA 23294 (804)644-8707 x 314 --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
