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Date: Mon, 2 Mar 1992 14:34 EST
From: email@example.com (Thomas J. Klehr)
I find that running our Symbolics 3670 with Genera 8.0 for an extended
period of time without warm-booting it causes a buildup of TCP
connections; these are shown in Peek. Is there a patch to get rid of
old connections that are no longer in use?
Are most of them TCP-FTP connections in CLOSED state? I've noticed this
problem for a couple of years, but only bothered investigating it last
The following should get rid of any closed connections that are still in
(remove :closed tcp::*tcb-list*
:key #'tcp::tcb-state :test-not #'eq))
Here's the message I sent to Symbolics about the problem. Warning about
the patch I included: I tried it out when I sent the message, but I
never actually installed it, so it hasn't had extensive testing. We
don't make much use of FTP (we mostly use NFS), so the bug isn't a
serious problem for us. Note also that the patch is for the 8.1 system;
I don't know offhand whether the 8.0 version of this method is the same.
The change is simple, though, and highlighted in uppercase.
Date: Thu, 29 Aug 1991 18:03-0400
Subject: TCP-FTP connection not closed
In Symbolics 3645 Genera 8.1, IP-TCP 435.2, ...
world booted from FEP0:>starlisp-6-1-v21.load.1 on Symbolics 3645 #5576
There seem to be some paths through TCP and TCP-FTP that can cause TCP
connections to be left around when they should have become garbage.
This message reports the TCP-FTP problem, and I'll report the others in
I used TCP-FTP to read a file on a Unix file server. Then I kill the
FTP server process, so it closes the connection. This caused the TCP
connection to go to the CLOSE-WAIT state. Shortly thereafter the file
connection scavenger deleted the TCP-FTP-CONN from the file access
path's CONNS list; however, the TCP stream was never closed, so the
connection is still listed by Peek Network. I believe the problem is in
the second loop in (FLAVOR:METHOD :SCAVENGE
FS:TCP-FTP-FILE-ACCESS-PATH). When FTP-CONNECTED-P returns NIL, the
connection is deleted from the CONNS list, but it is never reset.
FTP-CONNECTED-P returns NIL for a connection in CLOSE-WAIT state.
Here's a patch that seems to fix this problem:
(defmethod (:scavenge tcp-ftp-file-access-path) ()
(let ((scavenge-time (send self :control-connection-lifetime)))
(dolist (conn conns)
(send conn :scavenge scavenge-time)))
(loop for conn in conns
with conns-remaining = nil
when (ftp-connected-p conn)
do (setq conns-remaining t)
else do (SEND CONN :RESET) ;IN CASE IT'S ONLY HALF-CLOSED
(setq conns (delete conn conns))
finally (return conns-remaining))
(send self :reset))