From: Daniel Borkmann <daniel@iogearbox.net>
To: Lukas Wunner <lukas@wunner.de>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
Jozsef Kadlecsik <kadlec@netfilter.org>,
Florian Westphal <fw@strlen.de>,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org, Martin Mares <mj@ucw.cz>
Subject: Re: [PATCH nf-next,RFC 5/5] netfilter: Introduce egress hook
Date: Thu, 31 Oct 2019 23:39:58 +0100 [thread overview]
Message-ID: <d5876ef3-bcee-e0b2-273e-e0405fe17b79@iogearbox.net> (raw)
In-Reply-To: <de461181e53bcec9a75a9630d0d998d555dc8bf5.1572528497.git.lukas@wunner.de>
On 10/31/19 2:41 PM, Lukas Wunner wrote:
> Commit e687ad60af09 ("netfilter: add netfilter ingress hook after
> handle_ing() under unique static key") introduced the ability to
> classify packets on ingress.
>
> Allow the same on egress.
>
> The need for this arose because I had to filter egress packets which do
> not match a specific ethertype. The most common solution appears to be
This seems like a /very/ weak justification for something that sits in
critical fastpath. NAK.
> to enslave the interface to a bridge and use ebtables, but that's
> cumbersome to configure and comes with a (small) performance penalty.
> An alternative approach is tc, but that doesn't afford equivalent
> matching options as netfilter.
Hmm, have you tried tc BPF on the egress hook (via sch_cls_act -> cls_bpf)?
> people have expressed a desire for egress filtering in the past:
>
> https://www.spinics.net/lists/netfilter/msg50038.html
Adding another hook to catch misconfigurations of NAT in postrouting ...?
> https://unix.stackexchange.com/questions/512371
This talks about filtering / limiting ARP packets which can be done today
easily with existing means, including writing ARP responders sitting on tc
ingress/egress hook.
> An egress hook therefore seems like an obvious addition.
>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
next prev parent reply other threads:[~2019-10-31 22:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-31 13:41 [PATCH nf-next,RFC 0/5] Netfilter egress hook Lukas Wunner
2019-10-31 13:41 ` [PATCH nf-next,RFC 1/5] netfilter: Clean up unnecessary #ifdef Lukas Wunner
2019-10-31 13:41 ` [PATCH nf-next,RFC 2/5] netfilter: Document ingress hook Lukas Wunner
2019-10-31 13:41 ` [PATCH nf-next,RFC 3/5] netfilter: Rename ingress hook include file Lukas Wunner
2019-10-31 13:41 ` [PATCH nf-next,RFC 4/5] netfilter: Generalize ingress hook Lukas Wunner
2019-10-31 13:41 ` [PATCH nf-next,RFC 5/5] netfilter: Introduce egress hook Lukas Wunner
2019-10-31 22:39 ` Daniel Borkmann [this message]
2019-11-23 14:23 ` Lukas Wunner
2019-11-07 22:51 ` [PATCH nf-next,RFC 0/5] Netfilter " Pablo Neira Ayuso
2019-11-23 13:11 ` Lukas Wunner
2020-03-04 9:50 ` Lukas Wunner
2020-03-04 12:31 ` Pablo Neira Ayuso
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