Date: Thu, 14 Aug 2014 05:48:03 -0700 From: Mehmet Erol Sanliturk <m.e.sanliturk@gmail.com> To: Marko Zec <zec@fer.hr> Cc: "Alexander V. Chernikov" <melifaro@yandex-team.ru>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Luigi Rizzo <rizzo@iet.unipi.it>, freebsd-ipfw <freebsd-ipfw@freebsd.org> Subject: Re: [CFT] new tables for ipfw Message-ID: <CAOgwaMvg=q8n8ntiTAMjgQMdin0g=aJ4ud7Ss3P0ofF8gWFZRg@mail.gmail.com> In-Reply-To: <20140814140818.3539d9c5@x23> References: <53EBC687.9050503@yandex-team.ru> <CA%2BhQ2%2Bg=A_rLHCVpBqn0AtFLu_gNGtzbmXvc-7JhpLqPSWw44A@mail.gmail.com> <53EC880B.3020903@yandex-team.ru> <CA%2BhQ2%2BiPPhy47eN0=KaSYBaNMdObY20yko7dRY1MMuP_mfnmOQ@mail.gmail.com> <53EC960A.1030603@yandex-team.ru> <CA%2BhQ2%2BgxVYmXb%2BHOw4qUm6tykmEvBRkrV0RhZsnC6B08FLKvdA@mail.gmail.com> <53ECA302.8010100@yandex-team.ru> <20140814140818.3539d9c5@x23>
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On Thu, Aug 14, 2014 at 5:08 AM, Marko Zec <zec@fer.hr> wrote: > On Thu, 14 Aug 2014 15:52:34 +0400 > "Alexander V. Chernikov" <melifaro@yandex-team.ru> wrote: > > > On 14.08.2014 15:15, Luigi Rizzo wrote: > > > > > > > > > > > > On Thu, Aug 14, 2014 at 12:57 PM, Alexander V. Chernikov > > > <melifaro@yandex-team.ru <mailto:melifaro@yandex-team.ru>> wrote: > > > > > > On 14.08.2014 14:44, Luigi Rizzo wrote: > > >> > > >> > > >> > > >> On Thu, Aug 14, 2014 at 11:57 AM, Alexander V. Chernikov > > >> <melifaro@yandex-team.ru <mailto:melifaro@yandex-team.ru>> > > >> wrote: > > >> > > >> On 14.08.2014 13:23, Luigi Rizzo wrote: > > >>> > > >>> > > >>> > > >>> On Wed, Aug 13, 2014 at 10:11 PM, Alexander V. Chernikov > > >>> <melifaro@yandex-team.ru <mailto:melifaro@yandex-team.ru>> > > >>> wrote: > > >>> > > >>> Hello list. > > >>> > > >>> I've been hacking ipfw for a while and It seems there > > >>> is something ready to test/review in projects/ipfw branch. > > >>> > > >>> > > >>> =E2=80=8Bthis is a fantastic piece of work, thanks for doin= g it > > >>> and for integrating the feedback. > > >>> =E2=80=8B > > >>> I have some detailed feedback that will send you > > >>> privately, but just a curiosity: > > >>> > > >>> =E2=80=8B...=E2=80=8B > > >>> > > >>> Some examples (see ipfw(8) manual page for the > > >>> description): > > >>> > > >>> =E2=80=8B... > > >>> > > >>> > > >>> ipfw table mi_test create type cidr algo "cidr:hash > > >>> masks=3D/30,/64" > > >>> > > >>> > > >>> =E2=80=8Bwhy do we need to specify mask lengths in the abov= e=E2=80=8B ? > > >> Well, since we're hashing IP we have to know mask to cut > > >> host bits in advance. > > >> (And the real reason is that I'm too lazy to implement > > >> hierarchical matching (check /32, then /31, then /30) like > > >> how, for example, > > >> > > >> > > >> =E2=80=8Boh well for that we should use cidr:radix > > >> > > >> Research results have never shown a strong superiority of > > >> hierarchical hash tables over good radix implementations, > > >> and in those cases one usually adopts partial prefix > > >> expansion so you only have, say, masks that are a > > >> multiple of 2..8 bits so you only need a small number of > > >> hash lookups. > > > Definitely, especially for IPv6. So I was actually thinking > > > about covering some special sparse cases (e.g. someone having a > > > bunch of /32 and a bunch of /30 and that's all). > > > > > > Btw, since we're talking about "good radix implementation": what > > > license does DXR have? :) > > > Is it OK to merge it as another cidr implementation? > > > > > > "cidr" is a very ugly name, i'd rather use "addr" > > Ok, no problem with that. "addr" really sounds better. > > > > > > DXR has a =E2=80=8Bbsd license and of course it is possible to use it= . > > > You should ask Marko Zec for his latest version of the code > > > (and probably make sure we have one copy of the code in the source > > > tree). > > Great!. I'll ask him :) > > The so far cleanest DXR implementation is significantly C++ poluted and > wrapped inside Click glue (available here: http://www.nxab.fer.hr/dxr) > > I'll try to backport the fixes to the original C-only / BSD > implementation over the weekend and let you know how it goes... > > Marko > > > > > > > > Speaking of features, one thing that would be nice is the ability > > > for tables to reference the in-kernel tables (e.g. fibs, socket > > > lists, interface lists...), perhaps in readonly mode. > > > How complex do you think that would be ? > > Implementing algo support for particular provider like > > sockets/iflists shouldn't be hard. Most of the algorithms complexity > > lies in table modifications. Here we have to support > > lookup and dump operations, so it is the question of providing > > necessary bindings to existing mechanisms (via some direct binding or > > utilizing things like kernel_sysctl for dump support). > > > > It looks like the following maps well to current table concept: > > * such tables are not created by default > > * user issues > > `ipfw table kfib create type addr algo "addr:kernel fib=3D0"` > > or > > `ipfw table ktcp create type flow algo "flow:kernel_tcp fib=3D0"` > > or > > `ipfw table kiface create type iface algo "iface:kernel"` > > * tables have special "readonly" type, flush_all requests are ignored > > * no state stored internally > > > > So generic table handling code needs to be modified to support > > read-only tables (and making more callbacks optional). > > Additionally, we might need to proxy "info" request info algo > > callback (optional, "real" algorithms won't implement it) to be able > > to show number of items (and some other info) to user. > > > > > > > > > > > > cheers > > > luigi > > > > > > > _______________________________________________ > > freebsd-net@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-net > > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" The link is http://www.nxlab.fer.hr/dxr/ Thank you very much . Mehmet Erol Sanliturk
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