[src/trunk]: src add ppsratecheck(9).

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1f81d0894f5f
branches:  trunk
changeset: 495686:1f81d0894f5f
user:      itojun <itojun%NetBSD.org@localhost>
date:      Thu Aug 03 00:09:39 2000 +0000

description:
add ppsratecheck(9).

diffstat:

 distrib/sets/lists/comp/mi    |   4 +-
 share/man/man9/Makefile       |   6 +-
 share/man/man9/ppsratecheck.9 |  95 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 101 insertions(+), 4 deletions(-)

diffs (144 lines):

diff -r c6857893b1fc -r 1f81d0894f5f distrib/sets/lists/comp/mi
--- a/distrib/sets/lists/comp/mi        Thu Aug 03 00:07:22 2000 +0000
+++ b/distrib/sets/lists/comp/mi        Thu Aug 03 00:09:39 2000 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: mi,v 1.251 2000/08/01 00:53:14 wiz Exp $
+#      $NetBSD: mi,v 1.252 2000/08/03 00:09:40 itojun Exp $
 ./sys                  comp-sysutil-root
 ./usr/bin/addr2line    comp-miscutil-bin
 ./usr/bin/ar           comp-util-bin
@@ -2910,6 +2910,7 @@
 ./usr/share/man/cat9/pool_setlowat.0           comp-kern-catman
 ./usr/share/man/cat9/powerhook_disestablish.0          comp-kern-catman
 ./usr/share/man/cat9/powerhook_establish.0             comp-kern-catman
+./usr/share/man/cat9/ppsratecheck.0            comp-kern-catman
 ./usr/share/man/cat9/printf.0          comp-kern-catman
 ./usr/share/man/cat9/psignal.0         comp-kern-catman
 ./usr/share/man/cat9/ratecheck.0               comp-kern-catman
@@ -4555,6 +4556,7 @@
 ./usr/share/man/man9/pool_setlowat.9           comp-kern-man
 ./usr/share/man/man9/powerhook_disestablish.9          comp-kern-man
 ./usr/share/man/man9/powerhook_establish.9             comp-kern-man
+./usr/share/man/man9/ppsratecheck.9            comp-kern-man
 ./usr/share/man/man9/printf.9          comp-kern-man
 ./usr/share/man/man9/psignal.9         comp-kern-man
 ./usr/share/man/man9/ratecheck.9               comp-kern-man
diff -r c6857893b1fc -r 1f81d0894f5f share/man/man9/Makefile
--- a/share/man/man9/Makefile   Thu Aug 03 00:07:22 2000 +0000
+++ b/share/man/man9/Makefile   Thu Aug 03 00:09:39 2000 +0000
@@ -1,4 +1,4 @@
-#       $NetBSD: Makefile,v 1.67 2000/07/25 21:12:46 pk Exp $
+#       $NetBSD: Makefile,v 1.68 2000/08/03 00:09:39 itojun Exp $
 
 #      Makefile for section 9 (kernel function and variable) manual pages.
 
@@ -7,8 +7,8 @@
        doshutdownhooks.9 ethersubr.9 evcnt.9 extent.9 fetch.9 fork1.9 \
        humanize_number.9 inittodr.9 intro.9 ioctl.9 kprintf.9 \
        lock.9 log.9 malloc.9 mbuf.9 microtime.9 panic.9 pfil.9 physio.9 \
-       pool.9 powerhook_establish.9 psignal.9 ratecheck.9 resettodr.9 \
-       rnd.9 rt_timer.9 shutdownhook_establish.9 \
+       pool.9 powerhook_establish.9 ppsratecheck.9 psignal.9 ratecheck.9 \
+       resettodr.9 rnd.9 rt_timer.9 shutdownhook_establish.9 \
        sleep.9 softintr.9 spl.9 store.9 time.9 todr.9 uiomove.9 ucom.9 \
        usbdi.9 uvm.9 wdc.9
 MLINKS+=arp.9 arp_ifinit.9 arp.9 arpresolve.9 arp.9 arpintr.9
diff -r c6857893b1fc -r 1f81d0894f5f share/man/man9/ppsratecheck.9
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/share/man/man9/ppsratecheck.9     Thu Aug 03 00:09:39 2000 +0000
@@ -0,0 +1,95 @@
+.\"    $NetBSD: ppsratecheck.9,v 1.1 2000/08/03 00:09:39 itojun Exp $
+.\"
+.\" Copyright (c) 2000 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Jun-ichiro itojun Hagino.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"        This product includes software developed by the NetBSD
+.\"        Foundation, Inc. and its contributors.
+.\" 4. Neither the name of The NetBSD Foundation nor the names of its
+.\"    contributors may be used to endorse or promote products derived
+.\"    from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd August 3, 2000
+.Dt PPSRATECHECK 9
+.Os
+.Sh NAME
+.Nm ppsratecheck
+.Nd function to help implement rate-limited actions
+.Sh SYNOPSIS
+.Fd #include <sys/time.h>
+.Ft int
+.Fn ppsratecheck "struct timeval *lasttime" "int *curpps" "int maxpps"
+.Sh DESCRIPTION
+The
+.Fn ppsratecheck
+function provides easy way to perform packet-per-sec,
+or event-per-sec, rate limitation.
+The motivation for implementing
+.Fn ppsratecheck
+was to provide a mechanism that could be used to add rate limitation to
+network packet output.
+For certain network packets, we may want to impose rate limitation,
+to avoid denial-of-service attack possibilities.
+.Pp
+.Fa maxpps
+specifies maximum permitted packets, or events, per second.
+If
+.Fn ppsratecheck
+is called more than
+.Fa maxpps
+times in a given one second period,
+the function will return 0, indicating that we exceeded the limit.
+If we are below the limit, the function will return 1.
+If
+.Fa maxpps
+is set to 0, the function will always return 0
+.Pq no packets/events are permitted .
+Negative
+.Fa maxpps
+indicates that rate limitation is disabled, and
+.Fa ppsratecheck
+will always return 1.
+.Pp
+.Fa curpps
+and
+.Fa lasttime
+are used to maintain the number of recent calls.
+.Fa curpps
+will be incremented every time
+.Fn ppsratecheck
+is called, and will be reset whenever necessary.
+.Sh SEE ALSO
+.Xr log 9 ,
+.Xr printf 9 ,
+.Xr ratecheck 9 ,
+.Xr time 9
+.Sh HISTORY
+The
+.Fn ppsratecheck
+function appeared in
+.Nx 1.5 .