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From: Phil Sutter <phil@nwl.cc>
To: "Serguei Bezverkhi (sbezverk)" <sbezverk@cisco.com>
Cc: "netfilter-devel@vger.kernel.org" <netfilter-devel@vger.kernel.org>
Subject: Re: Numen with reference to vmap
Date: Wed, 4 Dec 2019 11:18:19 +0100
Message-ID: <20191204101819.GN8016@orbyte.nwl.cc> (raw)
In-Reply-To: <EC8889A1-27E2-4DC9-B752-514689982085@cisco.com>

Hi Serguei,

On Wed, Dec 04, 2019 at 12:54:05AM +0000, Serguei Bezverkhi (sbezverk) wrote:
> Nftables wiki gives this example for numgen:
> 
> nft add rule nat prerouting numgen random mod 2 vmap { 0 : jump mychain1, 1 : jump mychain2 }
> 
> I would like to use it but with map reference, like this:
> 
> nft add rule nat prerouting numgen random mod 2 vmap @service1-endpoints
> 
> Could you please confirm if it is supported? If it is what would be the type of the key in such map? I thought it would be integer, but command fails.
> 
> sudo nft --debug all add map ipv4table k8s-57XVOCFNTLTR3Q27-endpoints   { type  integer : verdict \; }
> Error: unqualified key type integer specified in map definition
> add map ipv4table k8s-57XVOCFNTLTR3Q27-endpoints { type integer : verdict ; }
>                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^

Yes, this is sadly not possible right now. numgen type is 32bit integer,
but we don't have a type definition matching that. Type 'integer' is
unqualified regarding size, therefore unsuitable for use in map/set
definitions.

This all works when using anonymous set/map because key type is
deduced from map LHS.

We plan to support a 'typeof' keyword at some point to allow for the
same deduction from within named map/set declarations, but it needs
further work as the type info is lost on return path (when listing) so
it would create a ruleset that can't be fed back.

> The ultimate  goal is to update dynamically just the  map  with available endpoints and loadbalance between them without  touching the rule.

I don't quite understand why you need to dynamically change the
load-balancing rule: numgen modulus is fixed anyway, so the number of
elements in vmap are fixed. Maybe just jump to chains and dynamically
update those instead?

Cheers, Phil

  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-04  0:54 Serguei Bezverkhi (sbezverk)
2019-12-04 10:18 ` Phil Sutter [this message]
2019-12-04 13:47   ` Serguei Bezverkhi (sbezverk)
2019-12-04 15:17     ` Phil Sutter
2019-12-04 15:42       ` Serguei Bezverkhi (sbezverk)
2019-12-04 15:56         ` Phil Sutter
2019-12-04 16:13           ` Serguei Bezverkhi (sbezverk)
2019-12-04 17:00             ` Phil Sutter
2019-12-04 17:31           ` Arturo Borrero Gonzalez
2019-12-04 17:49             ` Serguei Bezverkhi (sbezverk)
2019-12-04 21:05               ` Serguei Bezverkhi (sbezverk)
2019-12-04 22:32             ` Phil Sutter
2019-12-17  0:51               ` Serguei Bezverkhi (sbezverk)
2019-12-17 12:29                 ` Phil Sutter
2019-12-17 14:05                   ` Serguei Bezverkhi (sbezverk)
2019-12-17 16:41                     ` Phil Sutter
2019-12-18 17:01                       ` Serguei Bezverkhi (sbezverk)
2019-12-18 17:24                         ` Phil Sutter
2019-12-18 19:43                           ` Serguei Bezverkhi (sbezverk)
2019-12-18 19:58                             ` Laura Garcia
2019-12-18 20:54                               ` Serguei Bezverkhi (sbezverk)
2019-12-19 10:48                               ` Phil Sutter
2019-12-19 14:59                                 ` Serguei Bezverkhi (sbezverk)
2019-12-19 15:45                                   ` Phil Sutter
2019-12-19 16:00                                     ` Serguei Bezverkhi (sbezverk)
2019-12-19 18:19                                       ` Serguei Bezverkhi (sbezverk)
2020-01-04 12:30                                         ` Serguei Bezverkhi (sbezverk)

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