From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Jeremy Sowden <jeremy@azazel.net>
Cc: Florian Westphal <fw@strlen.de>,
Netfilter Devel <netfilter-devel@vger.kernel.org>
Subject: Re: [PATCH nftables 8/8] test: py: add tests for shifted nat port-ranges
Date: Wed, 3 May 2023 22:54:11 +0200 [thread overview]
Message-ID: <ZFLJ886DVa1d53kc@calendula> (raw)
In-Reply-To: <20230425195143.GC5944@celephais.dreamlands>
On Tue, Apr 25, 2023 at 08:51:43PM +0100, Jeremy Sowden wrote:
> On 2023-04-12, at 13:06:02 +0200, Pablo Neira Ayuso wrote:
> > On Tue, Apr 11, 2023 at 01:21:40PM +0100, Jeremy Sowden wrote:
> > > On 2023-03-26, at 22:39:42 +0200, Pablo Neira Ayuso wrote:
> > > > Jeremy, may I suggest you pick up on the bitwise _SREG2 support?
> > > > I will post a v4 with small updates for ("mark statement support
> > > > for non-constant expression") tomorrow. Probably you don't need
> > > > the new AND and OR operations for this? Only the a new _SREG2 to
> > > > specify that input comes from non-constant?
> > >
> > > Just to clarify, do you want just the `_SREG2` infrastructure from
> > > the last patch series but without the new bitwise ops? That is to
> > > say it would be possible to send two operands to the kernel in
> > > registers, but no use would be made of it (yet). Or are you
> > > proposing to update the existing mask-and-xor ops to send right hand
> > > operands via registers?
> >
> > I mean, would it be possible to add a NFT_BITWISE_BOOL variant that
> > takes _SREG2 via select_ops?
>
> In an earlier version, instead of adding new boolean ops, I added
> support for passing the mask and xor arguments in registers:
>
> https://lore.kernel.org/netfilter-devel/20200224124931.512416-1-jeremy@azazel.net/
>
> Doing the same thing with one extra register is straightforward for AND
> and XOR:
>
> AND(x, y) = (x & y) ^ 0
> XOR(x, y) = (x & 1) ^ y
>
> since we can pass y in _SREG2 and 0 in _XOR for AND, and 1 in _MASK and
> y in _SREG2 for XOR. For OR:
>
> OR(x, y) = (x & ~y) ^ y
>
> it's a bit more complicated. Instead of getting both the mask and xor
> arguments from user space, we need to do something like passing y in
> _SREG2 alone, and then constructing the bitwise negation in the kernel.
>
> Obviously, this means that the kernel is no longer completely agnostic
> about the sorts of mask-and-xor expressions user space may send.
>
> Since that is the case, we could go further and just perform the
> original ope- rations. Thus if we get an boolean op with an _SREG2
> argument:
>
> * if there is an _XOR of 0, compute:
>
> _SREG & _SREG2
>
> * if there is a _MASK of 1, compute:
>
> _SREG ^ _SREG2
>
> * if there are no _MASK or _XOR arguments, compute:
>
> _SREG | _SREG2
OK, if my understanding is correct, these are the two options:
1) Infer from arguments the type of operation.
2) Have explicit NFT_BITWISE_{AND,OR,XOR} operations.
If so, I think it is better to stick to your original patch, where
explicit bitwise operations NFT_BITWISE_{_AND,_OR,_XOR} are added
(which is what you proposed last time IIRC).
Thanks for explaining.
next prev parent reply other threads:[~2023-05-03 20:54 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-05 10:14 [PATCH nftables 0/8] Support for shifted port-ranges in NAT Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 1/8] nat: add support for shifted port-ranges Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 2/8] masq: " Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 3/8] redir: " Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 4/8] json: formatting fixes Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 5/8] json: add support for shifted nat port-ranges Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 6/8] doc: correct NAT statement description Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 7/8] doc: add shifted port-ranges to nat statements Jeremy Sowden
2023-03-05 10:14 ` [PATCH nftables 8/8] test: py: add tests for shifted nat port-ranges Jeremy Sowden
2023-03-24 22:59 ` Florian Westphal
2023-03-25 10:35 ` Phil Sutter
2023-03-25 11:10 ` Jeremy Sowden
2023-03-26 20:41 ` Pablo Neira Ayuso
2023-03-26 20:39 ` Pablo Neira Ayuso
2023-03-27 11:08 ` Jeremy Sowden
2023-04-11 12:21 ` Jeremy Sowden
2023-04-12 11:06 ` Pablo Neira Ayuso
2023-04-25 19:51 ` Jeremy Sowden
2023-05-03 20:54 ` Pablo Neira Ayuso [this message]
2023-05-08 17:58 ` Jeremy Sowden
2023-05-08 19:47 ` Pablo Neira Ayuso
2023-04-11 8:28 ` Pablo Neira Ayuso
2023-04-11 10:25 ` Florian Westphal
2023-04-11 10:53 ` Pablo Neira Ayuso
2023-04-11 11:20 ` Florian Westphal
2023-04-11 11:43 ` Pablo Neira Ayuso
2023-04-11 12:28 ` Florian Westphal
2023-04-11 12:36 ` Florian Westphal
2023-04-12 11:22 ` Pablo Neira Ayuso
2023-04-12 11:43 ` Florian Westphal
2023-04-12 12:54 ` Pablo Neira Ayuso
2023-03-24 14:18 ` [PATCH nftables 0/8] Support for shifted port-ranges in NAT Florian Westphal
2023-03-24 16:07 ` Jeremy Sowden
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZFLJ886DVa1d53kc@calendula \
--to=pablo@netfilter.org \
--cc=fw@strlen.de \
--cc=jeremy@azazel.net \
--cc=netfilter-devel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).