Netfilter-Devel Archive on lore.kernel.org
 help / color / Atom feed
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
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>

  reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-31 13:41 [PATCH nf-next,RFC 0/5] Netfilter " 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

Reply instructions:

You may reply publically 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=d5876ef3-bcee-e0b2-273e-e0405fe17b79@iogearbox.net \
    --to=daniel@iogearbox.net \
    --cc=coreteam@netfilter.org \
    --cc=fw@strlen.de \
    --cc=kadlec@netfilter.org \
    --cc=lukas@wunner.de \
    --cc=mj@ucw.cz \
    --cc=netdev@vger.kernel.org \
    --cc=netfilter-devel@vger.kernel.org \
    --cc=pablo@netfilter.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

Netfilter-Devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/netfilter-devel/0 netfilter-devel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 netfilter-devel netfilter-devel/ https://lore.kernel.org/netfilter-devel \
		netfilter-devel@vger.kernel.org
	public-inbox-index netfilter-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.netfilter-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git