Date: Thu, 14 Aug 2014 19:20:58 +0400 From: "Alexander V. Chernikov" <melifaro@yandex-team.ru> To: Willem Jan Withagen <wjw@digiware.nl>, Luigi Rizzo <rizzo@iet.unipi.it> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Luigi Rizzo <luigi@freebsd.org>, freebsd-ipfw <freebsd-ipfw@freebsd.org>, "Andrey V. Elsukov" <ae@freebsd.org> Subject: Re: [CFT] new tables for ipfw Message-ID: <53ECD3DA.6060501@yandex-team.ru> In-Reply-To: <53ECA6B2.8010003@digiware.nl> 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> <53ECA6B2.8010003@digiware.nl>
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On 14.08.2014 16:08, Willem Jan Withagen wrote: > On 2014-08-14 13:15, Luigi Rizzo wrote: >> On Thu, Aug 14, 2014 at 12:57 PM, Alexander V. Chernikov < >> 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> 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> 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. >>>>> >>>> >>>> this is a fantastic piece of work, thanks for doing it and for >>>> integrating the feedback. >>>> >>>> I have some detailed feedback that will send you privately, >>>> but just a curiosity: >>>> >>>> ... >>>>> >>>>> Some examples (see ipfw(8) manual page for the description): >>>>> >>>>> >>>>> ... >>>>> >>>>> >>>>> ipfw table mi_test create type cidr algo "cidr:hash masks=/30,/64" >>>>> >>>> >>>> why do we need to specify mask lengths in the above ? >>>> >>>> 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, >>>> >>> >>> oh 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" >> >> DXR has a bsd 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). >> >> 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 ? > > I'm a very happy user of ipfw and I think these are nice improvements > and will make things more flexible... > > I have 2 nits to pick with the current version. > > I've found the notation ipnr:something rather frustrating when using > ipv6 addresses. Sort of like typing a ipv6 address in a browser, the > last :xx is always interpreted as portnumber, UNLESS you wrap it in []'s. > compare > 2001:4cb8:3:1::1 > 2001:4cb8:3:1::1:80 > [2001:4cb8:3:1::1]:80 > The first and the last are the same host but a different port, the > middle one is just a different host. > > Could/should we do the same in ipfw? Well, we should, but I'm unsure if we have host:port notation anywhere in current (or new) syntax: > > And I keep running into the > ipfw add deny all from table(50) to any > notation. the ()'s need to be escaped in most any shell. Where as I > look at the syntax there is little reason to require the ()'s. > the keyword table always needs to be followed by a number (and in the > new version a (word|number) ). We need _some_ discriminator to ensure that the next parameter after "to" or "from" is not hostname. We also have some other places where tables are used: "via interface|table(X)", lookup X, flow table(X) [new]. I agree that parenthesis might not be the best choice. (and something like :tablename:, %tablename%, or even table:tablename might look better). Theoretically, we can support both (old/new) and show rules with new one by default. > > Thanx for the nice work, > --WjW >
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