From: "Steven Levine" <ecs-isp@2rosenthals.com>
Message-ID: <688a6c15.61.mr2ice.fgrirsq@earthlink.net>
Date: Wed, 30 Jul 2025 12:01:41 -0700
To: "eCS ISP Mailing List" <ecs-isp@2rosenthals.com>
In-Reply-To: <list-13730496@2rosenthals.com>
Subject: Re: [eCS-ISP] socket - no buffer space availble

In <list-13730496@2rosenthals.com>, on 07/30/25
   at 11:54 AM, "Lewis G Rosenthal" <ecs-isp@2rosenthals.com> said:

Hi,

>I would expect lingertime or realslow to impact FIN_WAIT_2. Does neither?

I don't know.  The relevant code is in afinetk.os2, but I've not had a
need to look at it in detail.

The possibly equivalent FreeBSD code is

tcp_usrreq.c:786
	if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
		soisdisconnected(tp->t_inpcb->inp_socket);
		/* To prevent the connection hanging in FIN_WAIT_2 forever. */
		if (tp->t_state == TCPS_FIN_WAIT_2)
			tp->t_timer[TCPT_2MSL] = tcp_maxidle;
	}

maxidle is set by

tcp_timer.c:131
	tcp_maxidle = tcp_keepcnt * tcp_keepintvl;

tcp_keepintvl can vary.  I'm pretty sure this is the keepalive timeout,
but I've not verified this 100%.

> realslow sets the time in ticks for closing slow TW connections, and I 
>thought that FIN_WAIT_2 implied a slow connection (I need to pull that
>book  off the shelf when I get home, I guess).

realslow does not seem to exist in the FreeBSD sources.  It appears to
have been added by IBM.  Afinetk.os2 defines the symbols

afinetk.sys\6_3100\afinetk.map:125
 0001:00001B34       tcp_keepidle
 0001:00001B38       tcp_keepintvl
 0001:00001B3C       tcp_maxpersistidle
 0001:00001B40       RealSlowTimer
 0001:00001B48       route_timer
 0001:00001B4C       syncookietimer

among others.  As you can see, camel case symbol style differs from the
standard FreeBSD source style.  I've not looked in any detail at how the
code uses RealSlowTimer.  This should happen if this dicussion continues
sufficiently long.

>I think once the socket number is returned to the pool, identifying these
> "cling-ons" (Klingons?) will be tricky.

Agreed. There's also the issue that we don't know the socket number we
want to hack away at.

>Now I'll have to  look at the 3.2 sources myself. As you are wont to say,
>some people do  crossword puzzles... LOL

FWIW, my reference is

>g remote -v
origin  https://github.com/freebsd/freebsd (fetch)

>g tag
release/3.2.0

>gl log -1
commit c37538200ebdef38051ba82b76e6b2dab3bd2fdc
Author: cvs2svn <cvs2svn@FreeBSD.org>
Date:   Mon May 24 16:47:10 1999 +0000

    This commit was manufactured by cvs2svn to create tag
    'RELENG_3_2_0_RELEASE'.

Steven

-- 
----------------------------------------------------------------------
"Steven Levine" <steve53@earthlink.net>  Warp/DIY/BlueLion etc.
www.scoug.com www.arcanoae.com www.warpcave.com
----------------------------------------------------------------------