Subject: [PATCH nf-next,RFC 0/5] Netfilter egress hook

From: Lukas Wunner <[email-masked]>
Date: Thu, 31 Oct 2019 14:41:00 +0100

Introduce a netfilter egress hook to complement the existing ingress hook.

User space support for nft is submitted in a separate patch.

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
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.  A bit of googling reveals that more
people have expressed a desire for egress filtering in the past:

https://www.spinics.net/lists/netfilter/msg50038.html
https://unix.stackexchange.com/questions/512371

I am first performing traffic control with sch_handle_egress() before
performing filtering with nf_egress().  That order is identical to
ingress processing.  I'm wondering whether an inverse order would be
more logical or more beneficial.  Among other things it would allow
marking packets with netfilter on egress before performing traffic
control based on that mark.  Thoughts?

Lukas Wunner (5):
  netfilter: Clean up unnecessary #ifdef
  netfilter: Document ingress hook
  netfilter: Rename ingress hook include file
  netfilter: Generalize ingress hook
  netfilter: Introduce egress hook

 include/linux/netdevice.h         |   5 ++
 include/linux/netfilter_ingress.h |  58 -----------------
 include/linux/netfilter_netdev.h  | 102 ++++++++++++++++++++++++++++++
 include/uapi/linux/netfilter.h    |   1 +
 net/core/dev.c                    |  31 ++++++---
 net/netfilter/Kconfig             |   8 +++
 net/netfilter/core.c              |  24 +++++--
 net/netfilter/nft_chain_filter.c  |   4 +-
 8 files changed, 161 insertions(+), 72 deletions(-)
 delete mode 100644 include/linux/netfilter_ingress.h
 create mode 100644 include/linux/netfilter_netdev.h

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2.23.0