Date: Fri, 9 May 2014 11:56:23 +0200 From: Luigi Rizzo <rizzo@iet.unipi.it> To: Bill Yuan <bycn82@gmail.com> Cc: "freebsd-ipfw@freebsd.org" <freebsd-ipfw@freebsd.org>, Freddie Cash <fjwcash@gmail.com> Subject: Re: feature of `packet per second` Message-ID: <CA%2BhQ2%2Bj5wZYkAHmt18KicHDRhWt1y-ucfs-Dk5oCEOs4rTZ6%2BA@mail.gmail.com> In-Reply-To: <CAC%2BJH2yff-bpivvLPEEDQQqi998cVuoO62-LMRC=607JOXEwNw@mail.gmail.com> References: <5360F1F4.9060808@gmail.com> <5361105C.1040203@freebsd.org> <53611738.8010103@gmail.com> <CAOjFWZ4zRUmcjG-r--OqoGEWcSZoWhtTykgAAHzCjoEWsMVS9g@mail.gmail.com> <53611EB1.4000406@gmail.com> <CA%2BhQ2%2BhjjS=AXVdnaEdFOKY1DqiLuX9iP0gy3wo6FbwnEdq_Qw@mail.gmail.com> <5364E097.9020106@gmail.com> <CA%2BhQ2%2BgXC9uNdtH1VCGa%2Bs1dPNWjErC9qfgXmEnfQ4SQ6Rnz_g@mail.gmail.com> <536AD13B.6080907@gmail.com> <536AD941.9090102@gmail.com> <20140508073816.GB64368@onelab2.iet.unipi.it> <536BACA4.7010702@gmail.com> <90ff4a7ff9a1d1bac510bb04fc457a91.authenticated@ultimatedns.net> <CAC%2BJH2yff-bpivvLPEEDQQqi998cVuoO62-LMRC=607JOXEwNw@mail.gmail.com>
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On Fri, May 9, 2014 at 5:00 AM, Bill Yuan <bycn82@gmail.com> wrote:
> OK then I will submit it as a patch in this weekend.
>
>
=E2=80=8Bthank you, much appreciated.
Don't worry about the details on the manpage,
we can fix them at a later time, same as handling
corner cases with small HZ values etc.
cheers
luigi
=E2=80=8B
>
> On Fri, May 9, 2014 at 1:11 AM, Chris H <bsd-lists@bsdforge.com> wrote:
>
>> > On 5/8/14 15:38, Luigi Rizzo wrote:
>> >> On Thu, May 08, 2014 at 09:09:21AM +0800, bycn82 wrote:
>> >>> On 5/8/14 8:35, bycn82 wrote:
>> >>>> On 5/4/14 1:19, Luigi Rizzo wrote:
>> >>>>>
>> >>>>>
>> >>>>> On Sat, May 3, 2014 at 2:27 PM, bycn82<bycn82@gmail.com
>> >>>>> <mailto:bycn82@gmail.com>> wrote:
>> >>>>>
>> >>>>> On 5/2/14 16:59, Luigi Rizzo wrote:
>> >>>>>>
>> >>>>>>
>> >>>>>> On Wed, Apr 30, 2014 at 6:02 PM, bycn82<bycn82@gmail.com
>> >>>>>> <mailto:bycn82@gmail.com>> wrote:
>> >>>>>>
>> >>>>>>
>> >>>>>> fjwcash@gmail.com<mailto:fjwcash@gmail.com>
>> >>>>>> <mailto:fjwcash@gmail.com<mailto:fjwcash@gmail.com>>
>> >>>>>>
>> >>>>>> Thanks for your reply, and it is good to know the sysct=
l
>> >>>>>> for ICMP.
>> >>>>>>
>> >>>>>> finally it works.I just added a new `action` in firewall
>> and
>> >>>>>> it is called `pps`, that means it can be generic purpos=
e
>> >>>>>> while the net.inet.icmp.icmplim is only for ICMP traffic=
.
>> >>>>>>
>> >>>>>> the usage will be like below
>> >>>>>>
>> >>>>>> root@F10:/usr/src/sbin/ipfw # .*/ipfw add pps 1 icmp fro=
m
>> >>>>>> any to any*
>> >>>>>> 00100 pps 1 icmp from any to any
>> >>>>>> root@F10:/usr/src/sbin/ipfw # ./ipfw show
>> >>>>>> 00100 9 540 pps 1 icmp from any to any
>> >>>>>> 65535 13319 1958894 allow ip from any to any
>> >>>>>> root@F10:/usr/src/sbin/ipfw #
>> >>>>>>
>> >>>>>>
>> >>>>>> ???hi,
>> >>>>>> as julian said it would be great if you would like to share
>> your
>> >>>>>> code
>> >>>>>> so we can integrate it in future ipfw releases.
>> >>>>>> Once again citing Julian, dummynet is a bit of a superset of
>> pps but
>> >>>>>> not exactly, so i see value in the additional feature.
>> >>>>>>
>> >>>>>> One thing ???to keep in mind in the implementation:
>> >>>>>>
>> >>>>>> the burst size used for limiting is an important parameter
>> that
>> >>>>>> everyone forgets. 1 pps is basically "don't bother me".
>> >>>>>> 1000 pps could be "1000 packets every fixed 1-sec interval"
>> >>>>>> or "1 packet every ms" or (this is more difficult)
>> >>>>>> "20 pkt in the last 50ms interval".
>> >>>>>>
>> >>>>>> If i were to implement the feature i would add two parameter=
s
>> >>>>>> (burst, I_max) with reasonable defaults and compute the
>> internal
>> >>>>>> interval and max_count as follows
>> >>>>>> if (burst> max_pps * I_max)
>> >>>>>> burst =3D max_pps * I_max; // make sure it is not too
>> large
>> >>>>>> else if (burst< max_pps / HZ)
>> >>>>>> burst =3D max_pps * HZ; // nor too small
>> >>>>>> max_count =3D max_pps / burst;
>> >>>>>> interval =3D HZ * burst / max_pps;
>> >>>>>> count =3D 0; // actual counter
>> >>>>>>
>> >>>>>> then add { max_count, interval, timestamp, count } to the ru=
le
>> >>>>>> descriptor.
>> >>>>>> On incoming packets:
>> >>>>>>
>> >>>>>> if (ticks>=3D r->interval + r->timestamp) {
>> >>>>>> r->timestamp =3D r->ticks;
>> >>>>>> r->count =3D 1;
>> >>>>>> return ACCEPT;
>> >>>>>> }
>> >>>>>> if (r->count> r->max_count)
>> >>>>>> return DENY;
>> >>>>>> r->count++;
>> >>>>>> return ACCEPT;
>> >>>>>>
>> >>>>>> cheers
>> >>>>>> luigi
>> >>>>>>
>> >>>>> Hi Luigi,
>> >>>>> You are right, it will be more generic if provide two
>> parameters
>> >>>>> as you described,
>> >>>>> But this PPS feature should not be used to control the traffi=
c
>> >>>>> rate, the dummynet you provided is the correct way.
>> >>>>> So I am thinking in what kind of scenario, people need this P=
PS
>> >>>>> feature?
>> >>>>> in my opinion, people will use PPS only when they want to lim=
it
>> >>>>> the connections/transactions numbers. ( already have limit
>> >>>>> command to limit the connections)
>> >>>>> So I think provide a simple PPS feature is good enough, and w=
e
>> >>>>> can improve it if someone complaint on this.
>> >>>>>
>> >>>>>
>> >>>>> ???pps has a strong reason to exist because it is a lot cheaper
>> >>>>> than a dummynet pipe, and given its pur???pose is to police
>> >>>>> traffic (icmp, dns requests, etc) which should not even
>> >>>>> get close to the limit which is set, I think it is
>> >>>>> a completely reasonable feature to have.
>> >>>>>
>> >>>>> Given that the above code is the complete implementation
>> >>>>> with the two parameters (burst and interval) there is no
>> >>>>> reason not to use them, at least internally.
>> >>>>>
>> >>>>> Then you could choose not to expose them as part of the
>> >>>>> user interface (though since you are implementing a new
>> >>>>> option from scratch, it is completely trivial to
>> >>>>> parse 1, 2 or 3 arguments and set defaults for the others).
>> >>>>>
>> >>>>> cheers
>> >>>>> luigi
>> >>>> OK, PPS with 2 parameters , it is done,
>> >>>> But how to get the current time in millisecond?
>> >>>> any recommendation?
>> >>> In order to get the millisecond, i tried to include the timeb.h but =
i
>> >>> met below
>> >> FreeBSD has a global kernel variable called ticks which increments
>> >> (roughly) HZ times per second and is all you need for this
>> >> kind of coarse estimates.
>> >> In linux there is something similar (jiffies maybe ?),
>> >> and the code to build ipfw on linux does some reasonable
>> >> mapping.
>> >>
>> >> The code i posted is, i believe, complete and contains
>> >> all the details.
>> >>
>> >> cheers
>> >> luigi
>> >>
>> >>> n file included from
>> >>> /usr/src/sys/modules/ipfw/../../netpfil/ipfw/ip_fw2.c:42:
>> >>> @/sys/timeb.h:42:2: error: "this file includes<sys/timeb.h> which i=
s
>> >>> deprecated"
>> >>> [-Werror,-W#warnings]
>> >>> #warning "this file includes<sys/timeb.h> which is deprecated"
>> >>> ^
>> >>> any replacement for timeb.h
>> >
>> > Man page patch for PPS
>> >
>> > .It Cm pps Ar limit duration
>> > Rule with the
>> > .Cm pps
>> > keyword will allow the first
>> > .Ar limit
>> > packets in each
>> > .Ar duration
>> > milliseconds.
>> >
>> >- and it will be like blow
>> + and it will be below
>> > pps _limit duration_
>> > Rule with the pps keyword will allow the first _limit
>> > _packets in
>> > each _duration _milliseconds.
>> >
>> > is that OK?
>> Just a suggestion. :)
>>
>> --Chris
>> > _______________________________________________
>> > freebsd-ipfw@freebsd.org mailing list
>> > http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw
>> > To unsubscribe, send any mail to "freebsd-ipfw-unsubscribe@freebsd.org=
"
>> >
>>
>>
>
--=20
-----------------------------------------+-------------------------------
Prof. Luigi RIZZO, rizzo@iet.unipi.it . Dip. di Ing. dell'Informazione
http://www.iet.unipi.it/~luigi/ . Universita` di Pisa
TEL +39-050-2211611 . via Diotisalvi 2
Mobile +39-338-6809875 . 56122 PISA (Italy)
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