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From: Anand Raj Manickam <anandrm@gmail.com>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>, netfilter-devel@vger.kernel.org
Subject: Re: [RFC PATCH nft] src: add support for interface wildcard name
Date: Wed, 16 Oct 2013 18:48:04 +0530	[thread overview]
Message-ID: <CAEyr1FTnZV0tr4qCYSbW3MUotUXLUqMhs7k6zZO3_ip9WTn12A@mail.gmail.com> (raw)
In-Reply-To: <20131016130154.GA10886@localhost>

On Wed, Oct 16, 2013 at 6:31 PM, Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Wed, Oct 16, 2013 at 02:58:39PM +0200, Pablo Neira Ayuso wrote:
>> On Wed, Oct 16, 2013 at 01:00:43PM +0200, Florian Westphal wrote:
>> > Pablo Neira Ayuso <pablo@netfilter.org> wrote:
>> > > On Tue, Oct 15, 2013 at 04:23:13PM +0200, Florian Westphal wrote:
>> > > > Uses same syntax as iptables: itfname+.
>> > >
>> > > Good you're bringing up this issue, we've been discussing this for a
>> > > while with recent Anand's patch.
>> > >
>> > > > The '+' suffix is not stored on the kernel side; this approach
>> > > > is the same as the one used by iptables-nftables.
>> > >
>> > > Hm, it seems current iptables-nftables seems broken by:
>> > >
>> > > 73ea1cc nft: convert rule into a command state structure
>> >
>> > I tested with latest ipt-nft (42531b3a6) -- admittingly, I did only
>> > test xt-save output, which adds '+' postfix in the no-trailing-nul case.
>> >
>> > > >  Caveats:
>> > > >   - I am not convinced '+' is a good idea -- it is ambiguous since
>> > > >   'foo+' is a legal interface name.
>> > >
>> > > I think we can remove the '+' in nft, so we match exactly what we
>> > > pass for the ifname case, eg. iifname "eth".
>> >
>> > Hm.  "iifname eth1": Should it match eth1? Yes. But what about eth10,
>> > eth1.42, etc?  I think we need an explicit way to resolve the ambiguity;
>>
>> I think "iffname eth1" should mean match "eth1\0".
>
> Oh I see, the ambiguity comes from nft syntax, then we do need some
> the wildcard character, yes.
>
> We can add "ifname-mask eth0", thus,
>
>         ifname-mask eth1 means match "eth1", including eth1, eth1.0, etc.
>         ifname eth1 means match "eth1\0".

iptables use the mask in kernel (ip_packet_match)  to do the wildcard match.
Currently ipt-nft  does use the MASK for the rule validation and with
patch submitted earlier , it should now help us to ADD/DELETE rules.
The opinion here is to push the offset/mask validation on the
nft_meta_eval in kernel ?

  reply	other threads:[~2013-10-16 13:18 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-15 14:23 [RFC PATCH nft] src: add support for interface wildcard name Florian Westphal
2013-10-16 10:39 ` Pablo Neira Ayuso
2013-10-16 11:00   ` Florian Westphal
2013-10-16 11:02     ` Patrick McHardy
2013-10-16 12:58     ` Pablo Neira Ayuso
2013-10-16 13:01       ` Pablo Neira Ayuso
2013-10-16 13:18         ` Anand Raj Manickam [this message]
2013-10-20 11:49 ` Jan Engelhardt

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