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From: Phil Sutter <phil@nwl.cc>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: [nft PATCH RFC v2 3/4] Implement --echo option
Date: Thu, 27 Jul 2017 19:00:34 +0200	[thread overview]
Message-ID: <20170727170034.GT2235@orbyte.nwl.cc> (raw)
In-Reply-To: <20170727165647.GA10869@salvia>

On Thu, Jul 27, 2017 at 06:56:47PM +0200, Pablo Neira Ayuso wrote:
> On Thu, Jul 27, 2017 at 06:54:35PM +0200, Phil Sutter wrote:
> > On Thu, Jul 27, 2017 at 06:43:00PM +0200, Pablo Neira Ayuso wrote:
> > > On Thu, Jul 27, 2017 at 06:21:43PM +0200, Phil Sutter wrote:
> > > > diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
> > > > index 40096de04e963..70404f724808a 100644
> > > > --- a/include/linux/netfilter/nf_tables.h
> > > > +++ b/include/linux/netfilter/nf_tables.h
> > > > @@ -114,6 +114,7 @@ enum nf_tables_msg_types {
> > > >  	NFT_MSG_GETOBJ,
> > > >  	NFT_MSG_DELOBJ,
> > > >  	NFT_MSG_GETOBJ_RESET,
> > > > +	NFT_MSG_META_ECHO,
> > > 
> > > Why this?
> > 
> > See netlink_echo_callback(): I want to reuse monitor code as much as
> > possible, and therefore introduced that function as common callback
> > dispatching to monitor callbacks. In order to make them print data like
> > I want them to, I need to have an indicator. The simplest way was to
> > introduce this fake type which in callbacks acts as third option to
> > NFT_MSG_NEW* or NFT_MSG_DEL*.
> 
> Hm, there must be a way to reuse this code without adding a new
> message type. From a netlink perspective, users should just set on the
> NLM_ECHO flag to get echo reports. I don't want to have a new message
> type for this.

Ah, maybe you misinterpreted it's scope: I gave it this weird name
because that message type actually doesn't exist from kernel PoV. It's
solely used in between netlink_echo_callback() and the
netlink_events_*_cb() functions it calls. It's pretty much just a hack,
but allowed me to get by without bigger changes to the callback
functions shared with monitor code.

Cheers, Phil

  reply	other threads:[~2017-07-27 17:00 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-27 16:21 [nft PATCH RFC v2 0/4] Implement --echo option Phil Sutter
2017-07-27 16:21 ` [nft PATCH RFC v2 1/4] mnl: Consolidate mnl_batch_talk() parameters Phil Sutter
2017-07-27 16:21 ` [nft PATCH RFC v2 2/4] netlink: Pass nlmsg flags from rule.c Phil Sutter
2017-07-27 16:21 ` [nft PATCH RFC v2 3/4] Implement --echo option Phil Sutter
2017-07-27 16:43   ` Pablo Neira Ayuso
2017-07-27 16:54     ` Phil Sutter
2017-07-27 16:56       ` Pablo Neira Ayuso
2017-07-27 17:00         ` Phil Sutter [this message]
2017-07-27 16:21 ` [nft PATCH RFC v2 4/4] tests: Add a simple test suite for " Phil Sutter

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