Skip site navigation (1)Skip section navigation (2) 
Date:      Fri, 21 Jan 2000 00:03:04 -0500 (EST)
From:      Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
To:        Alfred Perlstein <bright@wintelcom.net>
Cc:        net@FreeBSD.ORG
Subject:   half-fix for stream.c
Message-ID:  <200001210503.AAA41221@khavrinen.lcs.mit.edu>
In-Reply-To: <20000120174115.C14030@fw.wintelcom.net>
References:  <20000120174115.C14030@fw.wintelcom.net>
next in thread | previous in thread | raw e-mail | index | archive | help 
<<On Thu, 20 Jan 2000 17:41:17 -0800, Alfred Perlstein <bright@wintelcom.net> said:

> you can find it at:
> http://www.freebsd.org/~alfred/tcp_fix.diff

Am I the only person who thinks we could use a generic kernel TBF
module for all of these random rate-limiters?

The copyright notices are longer than the code....

# This is a shell archive.  Save it in a file, remove anything before
# this line, and then unpack it by entering "sh file".  Note, it may
# create directories; files and directories will be owned by you and
# have default permissions.
#
# This archive contains:
#
#	tbf.c
#	tbf.h
#
echo x - tbf.c
sed 's/^X//' >tbf.c << 'END-of-tbf.c'
X/*
X * Copyright 2000 Massachusetts Institute of Technology
X *
X * Permission to use, copy, modify, and distribute this software and
X * its documentation for any purpose and without fee is hereby
X * granted, provided that both the above copyright notice and this
X * permission notice appear in all copies, that both the above
X * copyright notice and this permission notice appear in all
X * supporting documentation, and that the name of M.I.T. not be used
X * in advertising or publicity pertaining to distribution of the
X * software without specific, written prior permission.  M.I.T. makes
X * no representations about the suitability of this software for any
X * purpose.  It is provided "as is" without express or implied
X * warranty.
X * 
X * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
X * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
X * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
X * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
X * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
X * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
X * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
X * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
X * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
X * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
X * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
X * SUCH DAMAGE.
X */
X
X/*
X * This module implements a generic token-bucket filter (TBF).
X * This is a basic element of queueing systems.  Tokens accumulate
X * at a rate r (here called tbf_rate and measured in zorkmids per 
X * second) in a bucket with maximum size B (tbf_max).  When an activity
X * of cost n (zorkmids) is requested, n tokens are drawn from the bucket.
X * (If fewer than n zorkmids are available at that time, the request 
X * fails.)  The result limits the long-term rate of activity,
X * while allowing for some amount of burstiness.
X */
X
X#include <sys/systm.h>
X#include <sys/callout.h>
X#include <sys/tbf.h>
X
Xstatic LIST_HEAD(, tbf) tbfs;
Xstatic struct callout callout;
Xstatic int callout_started;
X
Xstatic void tbf_incr(void *dummy);
X
Xvoid
Xtbf_init(struct tbf *f, u_long rate, u_long max)
X{
X	if (!callout_started) {
X		LIST_INIT(&tbfs);
X		callout_init(&callout);
X		callout_reset(&callout, hz, tbf_incr, (void *)0);
X		callout_started = 1;
X	}
X
X	f->tbf_rate = rate;
X	f->tbf_max = max;
X	f->tbf_cur = rate;
X	LIST_INSERT_HEAD(&tbfs, f, tbf_link);
X}
X
Xint
Xtbf_check(struct tbf *f, u_long n)
X{
X	return (TBF_CHECK(f, n));
X}
X
Xstatic void
Xtbf_incr(void *dummy)
X{
X	struct tbf *f;
X	int s;
X
X	for (f = tbfs->lh_first; f != 0; f = f->tbf_link.le_next) {
X		s = splhigh();	/* splimp() might be good enough? */
X		f->tbf_cur = ulmin(f->tbf_max, f->tbf_cur + f->tbf_rate);
X		splx(s);
X	}
X	callout_reset(&callout, hz, tbf_incr, (void *)0);
X}
X
Xvoid
Xtbf_remove(struct tbf *f)
X{
X	int s = splclock();	/* XXX ??? */
X	LIST_REMOVE(f, tbf_link);
X	splx(s);
X}
END-of-tbf.c
echo x - tbf.h
sed 's/^X//' >tbf.h << 'END-of-tbf.h'
X/*
X * Copyright 2000 Massachusetts Institute of Technology
X *
X * Permission to use, copy, modify, and distribute this software and
X * its documentation for any purpose and without fee is hereby
X * granted, provided that both the above copyright notice and this
X * permission notice appear in all copies, that both the above
X * copyright notice and this permission notice appear in all
X * supporting documentation, and that the name of M.I.T. not be used
X * in advertising or publicity pertaining to distribution of the
X * software without specific, written prior permission.  M.I.T. makes
X * no representations about the suitability of this software for any
X * purpose.  It is provided "as is" without express or implied
X * warranty.
X * 
X * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
X * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
X * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
X * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
X * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
X * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
X * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
X * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
X * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
X * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
X * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
X * SUCH DAMAGE.
X */
X#ifndef _SYS_TBF_H_
X#define	_SYS_TBF_H_	1
X
X#include <sys/queue.h>
X
Xstruct tbf {
X	u_long	tbf_cur;
X	LIST_ENTRY(tbf)	tbf_link;
X	u_long	tbf_rate;
X	u_long	tbf_max;
X};
X
X#define	TBF_CHECK(f, n) ((f)->tbf_cur >= n ? ((f)->tbf_cur -= n, 1) : 0)
X
Xint	tbf_check(struct tbf *f, u_long n);
Xvoid	tbf_init(struct tbf *f, u_long tbf_rate, u_long tbf_max);
Xvoid	tbf_remove(struct tbf *f);
X
X#endif /* _SYS_TBF_H_ */
END-of-tbf.h
exit



To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-net" in the body of the message

Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200001210503.AAA41221>