From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Vlad Tsisyk <vlad@tsisyk.com>
Cc: netfilter@vger.kernel.org
Subject: Re: Mask as part of element in set
Date: Wed, 27 Mar 2024 10:16:32 +0100 [thread overview]
Message-ID: <ZgPj8I0MmgAX0O0a@calendula> (raw)
In-Reply-To: <CAOzR2PfY6hY8dqkfWzN2RGG2yU7RR1t-G4d=dqa+7iUy9mjFyw@mail.gmail.com>
On Wed, Mar 27, 2024 at 03:36:19PM +0700, Vlad Tsisyk wrote:
> Hello,
>
> I have a set of pairs of MAC address and mask:
>
> aa:bb:cc:dd:ee:ff 00:ff:ff:ff:ff:ff
You would like to match this?
xx:bb:cc:dd:ee:ff
or mark is reversed?
> aa:bb:cc:dd:ee:ff 00:ff:ff:ff:ff:00
>
> ...
>
> I want to apply a mask to source MAC from the packet, and then compare
> the result with the MAC from the pair. I can do it like so:
>
> nft add table t
> nft add chain t c
> nft --debug=netlink add rule ip t c ether saddr and aa:bb:cc:dd:ee:ff 00:ff:ff:ff:ff:00
because rule syntax is not correct, mask is reversed:
nft --debug=netlink add rule ip t c ether saddr and 00:ff:ff:ff:ff:00 == aa:bb:cc:dd:ee:ff
that is:
nft --debug=netlink add rule ip t c ether saddr and MASK == VALUE
> ip t c
> [ meta load iiftype => reg 1 ]
> [ cmp eq reg 1 0x00000001 ]
> [ payload load 6b @ link header + 6 => reg 1 ]
> [ bitwise reg 1 = (reg=1 & 0xddccbbaa 0x0000ffee ) ^ 0x00000000
> 0x00000000 ]
> [ cmp eq reg 1 0xffffff00 0x000000ff ]
> ...
>
> But I have to create a new rule for each pair. Is there any
> workarounds to use sets?
You can use ranges in sets.
next prev parent reply other threads:[~2024-03-27 9:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-27 8:36 Mask as part of element in set Vlad Tsisyk
2024-03-27 9:16 ` Pablo Neira Ayuso [this message]
2024-03-28 8:20 ` Vlad Tsisyk
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