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List:       openbsd-bugs
Subject:    kernel/1846: Honor TCPT_KEEP timer in state CLOSING
From:       Armin Wolfermann <armin () wolfermann ! org>
Date:       2001-05-31 9:23:14
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>Number:         1846
>Category:       kernel
>Synopsis:       Honor TCPT_KEEP timer in state CLOSING
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu May 31 03:00:03 MDT 2001
>Last-Modified:
>Originator:     Armin Wolfermann
>Organization:
net
>Release:        2.9
>Environment:
	System      : OpenBSD 2.9
	Architecture: OpenBSD.i386
	Machine     : i386
>Description:
	In a simultaneous close situation (server sends FIN, client
	sends FIN shortly after) the connection enters state CLOSING
	and a keepalive timer is set.
	
	When this counter expires no check on idle time is made and
	no probe packets are sent: the timer is reset to tcp_keepidle
	and the connection loops forever.
>How-To-Repeat:
	Run a lightly loaded webserver (2-3 hits/second) and observe
	TCP connection state (eg via netstat). After a month of uptime
	I had 100 connections looping in state CLOSING.
>Fix:

Index: tcp_timer.c
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_timer.c,v
retrieving revision 1.20
diff -u -r1.20 tcp_timer.c
--- tcp_timer.c 2000/12/13 09:47:08     1.20
+++ tcp_timer.c 2001/05/30 15:14:15
@@ -390,7 +390,7 @@
                if (TCPS_HAVEESTABLISHED(tp->t_state) == 0)
                        goto dropit;
                if (tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE &&
-                   tp->t_state <= TCPS_CLOSE_WAIT) {
+                   tp->t_state <= TCPS_CLOSING) {
                        if (tp->t_idle >= tcp_keepidle + tcp_maxidle)
                                goto dropit;
                        /*

>Audit-Trail:
>Unformatted:

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