All of lore.kernel.org
 help / color / mirror / Atom feed
From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Florian Westphal <fw@strlen.de>
Cc: "Carlos Falgueras García" <carlosfg@riseup.net>,
	netfilter-devel@vger.kernel.org, kaber@trash.net
Subject: Re: [PATCH 3/4 v2] libnftnl: set: Implement new buffer of TLV objects.
Date: Fri, 8 Jan 2016 14:41:27 +0100	[thread overview]
Message-ID: <20160108134127.GA24063@salvia> (raw)
In-Reply-To: <20160105132847.GA24311@breakpoint.cc>

Hi Florian,

On Tue, Jan 05, 2016 at 02:28:47PM +0100, Florian Westphal wrote:
> Carlos Falgueras García <carlosfg@riseup.net> wrote:
> > These functions allow create a buffer (nftnl_attrbuf) of TLV objects
> > (nftnl_attr). It is inspired in libmnl/src/attr.c.
> 
> It would be nice to get a summary on how this going to be used.
> 
> At this time I don't understand why nftnl needs this api,
> the kernel doesn't enforce any format on this data (good), so we cannot
> rely on it having any specific format when reading arbitrary userdata
> (added by someone else).

Since the introduction of concatenations, the NFTA_SET_DATA_TYPE
attribute became too short to store the datatype information that we
need to keep to interpret the elements datatypes. This field is very
useful when dumping things from the kernel, to interpret them given
that the kernel side has no understanding on the byte semantics that
it is storing.

Another problem is that we also don't want to have fixed integer
datatypes since we can also have header bitfields into sets, this
would also explode in number when consider host and network byteorder
variants, so the idea is to store this in flexible TLV format in the
set userdata area.
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

      reply	other threads:[~2016-01-08 13:41 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-05 13:03 [PATCH 1/4 v2] nf: netfilter: nf_tables_api: Add new attributes into nft_set to store user data Carlos Falgueras García
2016-01-05 13:03 ` [PATCH 3/4 v2] libnftnl: set: Implement new buffer of TLV objects Carlos Falgueras García
2016-01-05 13:28   ` Florian Westphal
2016-01-08 13:41     ` Pablo Neira Ayuso [this message]

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=20160108134127.GA24063@salvia \
    --to=pablo@netfilter.org \
    --cc=carlosfg@riseup.net \
    --cc=fw@strlen.de \
    --cc=kaber@trash.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.