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Message-ID: <531EE5A2.7090501@redhat.com>
Date: Tue, 11 Mar 2014 11:29:54 +0100
From: Daniel Borkmann <dborkman@...hat.com>
To: Pablo Neira Ayuso <pablo@...filter.org>
CC: netfilter-devel@...r.kernel.org, davem@...emloft.net,
netdev@...r.kernel.org, kaber@...sh.net,
Alexei Starovoitov <ast@...mgrid.com>,
Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH RFC 0/9] socket filtering using nf_tables
On 03/11/2014 10:19 AM, Pablo Neira Ayuso wrote:
> Hi!
>
> The following patchset provides a socket filtering alternative to BPF
> which allows you to define your filter using the nf_tables expressions.
>
> Similarly to BPF, you can attach filters via setsockopt()
> SO_ATTACH_NFT_FILTER. The filter that is passed to the kernel is
> expressed in netlink TLV format which looks like:
>
> expression list (nested attribute)
> expression element (nested attribute)
> expression name (string)
> expression data (nested attribute)
> ... specific attribute for this expression go here
>
> This is similar to the netlink format of the nf_tables rules, so we
> can re-use most of the infrastructure that we already have in userspace.
> The kernel takes the TLV representation and translates it to the native
> nf_tables representation.
>
> The patches 1-3 have helped to generalize the existing socket filtering
> infrastructure to allow pluging new socket filtering frameworks. Then,
> patches 4-8 generalize the nf_tables code by move the neccessary nf_tables
> expression and data initialization core infrastructure. Then, patch 9
> provides the nf_tables socket filtering capabilities.
>
> Patrick and I have been discussing for a while that part of this
> generalisation works should also help to add support for providing a
> replacement to the tc framework, so with the necessary work, nf_tables
> may provide in the near future packet a single packet classification
> framework for Linux.
I'm being curious here ;) as there's currently an ongoing effort on
netdev for Alexei's eBPF engine (part 1 at [1,2,3]), which addresses
shortcomings of current BPF and shall long term entirely replace the
current BPF engine code to let filters entirely run in eBPF resp.
eBPF's JIT engine, as I understand, which is also transparently usable
in cls_bpf for classification in tc w/o rewriting on a different filter
language. Performance figures have been posted/provided in [1] as well.
So the plan on your side would be to have an alternative to eBPF, or
build on top of it to reuse its in-kernel JIT compiler?
[1] http://patchwork.ozlabs.org/patch/328927/
[2] http://patchwork.ozlabs.org/patch/328926/
[3] http://patchwork.ozlabs.org/patch/328928/
> There is an example of the userspace code available at:
>
> http://people.netfilter.org/pablo/nft-sock-filter-test.c
>
> I'm currently reusing the existing libnftnl interfaces, my plan is to
> new interfaces in that library for easier and more simple filter
> definition for socket filtering.
>
> Note that the current nf_tables expression-set is also limited with
> regards to BPF, but the infrastructure that we have can be easily
> extended with new expressions.
>
> Comments welcome!
>
> Pablo Neira Ayuso (9):
> net: rename fp->bpf_func to fp->run_filter
> net: filter: account filter length in bytes
> net: filter: generalise sk_filter_release
> netfilter: nf_tables: move fast operations to header
> netfilter: nf_tables: add nft_value_init
> netfilter: nf_tables: rename nf_tables_core.c to nf_tables_nf.c
> netfilter: nf_tables: move expression infrastructure to built-in core
> netfilter: nf_tables: generalize verdict handling and introduce scopes
> netfilter: nf_tables: add support for socket filtering
>
> arch/arm/net/bpf_jit_32.c | 25 +-
> arch/powerpc/net/bpf_jit_comp.c | 10 +-
> arch/s390/net/bpf_jit_comp.c | 16 +-
> arch/sparc/net/bpf_jit_comp.c | 8 +-
> arch/x86/net/bpf_jit_comp.c | 8 +-
> include/linux/filter.h | 28 +-
> include/net/netfilter/nf_tables.h | 27 +-
> include/net/netfilter/nf_tables_core.h | 84 +++++
> include/net/netfilter/nft_reject.h | 3 +-
> include/net/sock.h | 8 +-
> include/uapi/asm-generic/socket.h | 4 +
> net/core/filter.c | 28 +-
> net/core/sock.c | 19 ++
> net/core/sock_diag.c | 4 +-
> net/netfilter/Kconfig | 13 +
> net/netfilter/Makefile | 9 +-
> net/netfilter/nf_tables_api.c | 440 ++++---------------------
> net/netfilter/nf_tables_core.c | 564 +++++++++++++++++++++-----------
> net/netfilter/nf_tables_nf.c | 189 +++++++++++
> net/netfilter/nf_tables_sock.c | 327 ++++++++++++++++++
> net/netfilter/nft_bitwise.c | 35 +-
> net/netfilter/nft_byteorder.c | 28 +-
> net/netfilter/nft_cmp.c | 43 ++-
> net/netfilter/nft_compat.c | 6 +-
> net/netfilter/nft_counter.c | 3 +-
> net/netfilter/nft_ct.c | 9 +-
> net/netfilter/nft_exthdr.c | 3 +-
> net/netfilter/nft_hash.c | 12 +-
> net/netfilter/nft_immediate.c | 35 +-
> net/netfilter/nft_limit.c | 3 +-
> net/netfilter/nft_log.c | 3 +-
> net/netfilter/nft_lookup.c | 3 +-
> net/netfilter/nft_meta.c | 51 ++-
> net/netfilter/nft_nat.c | 3 +-
> net/netfilter/nft_payload.c | 29 +-
> net/netfilter/nft_queue.c | 3 +-
> net/netfilter/nft_rbtree.c | 12 +-
> net/netfilter/nft_reject.c | 3 +-
> 38 files changed, 1416 insertions(+), 682 deletions(-)
> create mode 100644 net/netfilter/nf_tables_nf.c
> create mode 100644 net/netfilter/nf_tables_sock.c
>
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