From: Florian Westphal <fw@strlen.de>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: "Florian Westphal" <fw@strlen.de>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Network Development" <netdev@vger.kernel.org>,
"Toke Høiland-Jørgensen" <toke@kernel.org>,
netfilter-devel <netfilter-devel@vger.kernel.org>,
bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH nf-next] netfilter: nf_tables: add ebpf expression
Date: Wed, 31 Aug 2022 23:57:37 +0200 [thread overview]
Message-ID: <20220831215737.GE15107@breakpoint.cc> (raw)
In-Reply-To: <CAADnVQJGQmu02f5B=mc1xJvVWSmk_GNZj9WAUskekykmyo8FzA@mail.gmail.com>
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> > This helps gradually moving towards move epbf for those that
> > still heavily rely on the classic forwarding path.
>
> No one is using it.
> If it was, we would have seen at least one bug report over
> all these years. We've seen none.
Err, it IS used, else I would not have sent this patch.
> very reasonable early on and turned out to be useless with
> zero users.
> BPF_PROG_TYPE_SCHED_ACT and BPF_PROG_TYPE_LWT*
> are in this category.
I doubt it had 0 users. Those users probably moved to something
better?
> As a minimum we shouldn't step on the same rakes.
> xt_ebpf would be the same dead code as xt_bpf.
Its just 160 LOC or so, I don't see it has a huge technical debt.
> > If you are open to BPF_PROG_TYPE_NETFILTER I can go that route
> > as well, raw bpf program attachment via NF_HOOK and the bpf dispatcher,
> > but it will take significantly longer to get there.
> >
> > It involves reviving
> > https://lore.kernel.org/netfilter-devel/20211014121046.29329-1-fw@strlen.de/
>
> I missed it earlier. What is the end goal ?
Immediate goal: get rid of all indirect calls from NF_HOOK()
invocations. Its about 2% speedup in my tests (with connection
tracking+defrag enabled).
This series changes prototype of the callbacks to int foo(struct *),
so I think it would be possible to build on this and allow attaching raw
bpf progs/implement what is now a netfilter kernel module as a bpf
program.
I have not spent time on this so far though, so I don't know yet
how the "please attach prog id 12345 at FORWARD with prio 42" should
be done.
> Optimize nft run-time with on the fly generation of bpf byte code ?
This could be done too, so far this JITs nf_hook_slow() only.
The big question for nft run-time would be how and where to do the JIT
translation.
I think that "nft run time jit" would be step 3, after allowing
(re)implementation of netfilter modules via bpf programs.
next prev parent reply other threads:[~2022-08-31 21:58 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 10:16 [PATCH nf-next] netfilter: nf_tables: add ebpf expression Florian Westphal
2022-08-31 12:13 ` Toke Høiland-Jørgensen
2022-08-31 12:56 ` Florian Westphal
2022-08-31 13:41 ` Toke Høiland-Jørgensen
2022-08-31 13:57 ` Florian Westphal
2022-08-31 14:43 ` Toke Høiland-Jørgensen
2022-08-31 15:09 ` Pablo Neira Ayuso
2022-08-31 15:35 ` Florian Westphal
2022-08-31 20:38 ` Pablo Neira Ayuso
2022-08-31 15:26 ` Florian Westphal
2022-08-31 15:39 ` Alexei Starovoitov
2022-08-31 15:53 ` Florian Westphal
2022-08-31 17:26 ` Alexei Starovoitov
2022-08-31 21:49 ` Daniel Borkmann
2022-09-01 5:18 ` Eyal Birger
2022-09-02 16:53 ` Alexei Starovoitov
2022-09-05 17:50 ` Eyal Birger
2022-09-01 10:14 ` Florian Westphal
2022-09-02 17:06 ` Alexei Starovoitov
2022-09-02 17:52 ` Florian Westphal
2022-08-31 21:57 ` Florian Westphal [this message]
2022-09-06 6:57 ` Nicolas Dichtel
2022-09-07 3:04 ` Alexei Starovoitov
2022-09-07 15:52 ` Nicolas Dichtel
2022-09-01 8:08 ` Jan Engelhardt
2022-08-31 20:44 ` Toke Høiland-Jørgensen
2022-08-31 13:44 ` Florian Westphal
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