From: Jakub Sitnicki <jakub@cloudflare.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf <bpf@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
kernel-team <kernel-team@cloudflare.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Andrii Nakryiko <andriin@fb.com>,
Lorenz Bauer <lmb@cloudflare.com>,
Marek Majkowski <marek@cloudflare.com>,
Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>
Subject: Re: BPF sk_lookup v5 - TCP SYN and UDP 0-len flood benchmarks
Date: Fri, 21 Aug 2020 12:22:46 +0200 [thread overview]
Message-ID: <87imdcs3gp.fsf@cloudflare.com> (raw)
In-Reply-To: <CAADnVQ+MXozV0ZFNYmK5ehVzvktXDcrAq8Q1Z9COWnXcACOXWQ@mail.gmail.com>
On Fri, Aug 21, 2020 at 12:18 AM CEST, Alexei Starovoitov wrote:
> On Thu, Aug 20, 2020 at 3:29 AM Jakub Sitnicki <jakub@cloudflare.com> wrote:
>> On Tue, Aug 18, 2020 at 08:19 PM CEST, Alexei Starovoitov wrote:
[...]
>> > Long term we should probably stop doing *_kern style of ctx passing
>> > into bpf progs.
>> > We have BTF, CO-RE and freplace now. This old style of memset *_kern and manual
>> > ctx conversion has performance implications and annoying copy-paste of ctx
>> > conversion routines.
>> > For this particular case instead of introducing udp4_lookup_run_bpf()
>> > and copying registers into stack we could have used freplace of
>> > udp4_lib_lookup2.
>> > More verifier work needed, of course.
>> > My main point that existing approach "lets prep args for bpf prog to
>> > run" that is used
>> > pretty much in every bpf hook is no longer necessary.
>>
>> Andrii has also suggested leveraging BTF [0], but to expose the *_kern
>> struct directly to BPF prog instead of emitting ctx access instructions.
>>
>> What I'm curious about is if we get rid of prepping args and ctx
>> conversion, then how do we limit what memory BPF prog can access?
>>
>> Say, I'm passing a struct sock * to my BPF prog. If it's not a tracing
>> prog, then I don't want it to have access to everything that is
>> reachable from struct sock *. This is where this approach currently
>> breaks down for me.
>
> Why do you want to limit it?
> Time after time we keep extending structs in uapi/bpf.h because new
> use cases are coming up. Just let the prog access everything.
I guess I wasn't thinking big enough :-)
next prev parent reply other threads:[~2020-08-21 10:22 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 10:35 [PATCH bpf-next v5 00/15] Run a BPF program on socket lookup Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 01/15] bpf, netns: Handle multiple link attachments Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 02/15] bpf: Introduce SK_LOOKUP program type with a dedicated attach point Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 03/15] inet: Extract helper for selecting socket from reuseport group Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 04/15] inet: Run SK_LOOKUP BPF program on socket lookup Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 05/15] inet6: Extract helper for selecting socket from reuseport group Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 06/15] inet6: Run SK_LOOKUP BPF program on socket lookup Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 07/15] udp: Extract helper for selecting socket from reuseport group Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 08/15] udp: Run SK_LOOKUP BPF program on socket lookup Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 09/15] udp6: Extract helper for selecting socket from reuseport group Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 10/15] udp6: Run SK_LOOKUP BPF program on socket lookup Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 11/15] bpf: Sync linux/bpf.h to tools/ Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 12/15] libbpf: Add support for SK_LOOKUP program type Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 13/15] tools/bpftool: Add name mappings for SK_LOOKUP prog and attach type Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 14/15] selftests/bpf: Add verifier tests for bpf_sk_lookup context access Jakub Sitnicki
2020-07-17 10:35 ` [PATCH bpf-next v5 15/15] selftests/bpf: Tests for BPF_SK_LOOKUP attach point Jakub Sitnicki
2020-07-28 20:13 ` Andrii Nakryiko
2020-07-28 20:47 ` Daniel Borkmann
2020-07-29 8:55 ` Jakub Sitnicki
2020-07-31 0:04 ` Daniel Borkmann
2020-07-29 8:57 ` Jakub Sitnicki
2020-07-30 13:10 ` Jakub Sitnicki
2020-07-30 19:43 ` Andrii Nakryiko
2020-07-17 16:40 ` [PATCH bpf-next v5 00/15] Run a BPF program on socket lookup Lorenz Bauer
2020-07-18 3:25 ` Alexei Starovoitov
2020-08-18 15:49 ` BPF sk_lookup v5 - TCP SYN and UDP 0-len flood benchmarks Jakub Sitnicki
2020-08-18 18:19 ` Alexei Starovoitov
2020-08-20 10:29 ` Jakub Sitnicki
2020-08-20 12:20 ` David Laight
2020-08-20 22:18 ` Alexei Starovoitov
2020-08-21 10:22 ` Jakub Sitnicki [this message]
2020-08-24 8:17 ` Paolo Abeni
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