From: John Fastabend <john.fastabend@gmail.com>
To: "Jörn-Thorben Hinz" <jthinz@mailbox.tu-berlin.de>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, linux-kselftest@vger.kernel.org
Cc: "Jörn-Thorben Hinz" <jthinz@mailbox.tu-berlin.de>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Shuah Khan" <shuah@kernel.org>,
"Willem de Bruijn" <willemb@google.com>,
"Deepa Dinamani" <deepa.kernel@gmail.com>
Subject: RE: [PATCH 0/2] bpf, net: Allow setting SO_TIMESTAMPING* from BPF
Date: Mon, 03 Jul 2023 14:25:59 -0700 [thread overview]
Message-ID: <64a33ce7b50d2_6520520875@john.notmuch> (raw)
In-Reply-To: <20230703175048.151683-1-jthinz@mailbox.tu-berlin.de>
Jörn-Thorben Hinz wrote:
> BPF applications, e.g., a TCP congestion control, might benefit from
> precise packet timestamps. These timestamps are already available in
> __sk_buff and bpf_sock_ops, but could not be requested: A BPF program
> was not allowed to set SO_TIMESTAMPING* on a socket. This change enables
> BPF programs to actively request the generation of timestamps from a
> stream socket.
>
> To reuse the setget_sockopt BPF prog test for
> bpf_{get,set}sockopt(SO_TIMESTAMPING_NEW), also implement the missing
> getsockopt(SO_TIMESTAMPING_NEW) in the network stack.
>
> I reckon the way I added getsockopt(SO_TIMESTAMPING_NEW) causes an API
> change: For existing users that set SO_TIMESTAMPING_NEW but queried
> SO_TIMESTAMPING_OLD afterwards, it would now look as if no timestamping
> flags have been set. Is this an acceptable change? If not, I’m happy to
> change getsockopt() to only be strict about the newly-implemented
> getsockopt(SO_TIMESTAMPING_NEW), or not distinguish between
> SO_TIMESTAMPING_NEW and SO_TIMESTAMPING_OLD at all.
Yeah, I think it would be best if we keep the old behavior and let
SO_TIMESTAMPING_OLD return timestamps for both new/old. It looks
like it should be relatively easy to implement?
Otherwise the series lgtm.
>
> Jörn-Thorben Hinz (2):
> net: Implement missing getsockopt(SO_TIMESTAMPING_NEW)
> bpf: Allow setting SO_TIMESTAMPING* with bpf_setsockopt()
>
> include/uapi/linux/bpf.h | 3 ++-
> net/core/filter.c | 2 ++
> net/core/sock.c | 9 +++++++--
> tools/include/uapi/linux/bpf.h | 3 ++-
> tools/testing/selftests/bpf/progs/bpf_tracing_net.h | 2 ++
> tools/testing/selftests/bpf/progs/setget_sockopt.c | 4 ++++
> 6 files changed, 19 insertions(+), 4 deletions(-)
>
> --
> 2.39.2
>
>
next prev parent reply other threads:[~2023-07-03 21:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-03 17:50 [PATCH 0/2] bpf, net: Allow setting SO_TIMESTAMPING* from BPF Jörn-Thorben Hinz
2023-07-03 17:50 ` [PATCH 1/2] net: Implement missing getsockopt(SO_TIMESTAMPING_NEW) Jörn-Thorben Hinz
2023-07-03 17:50 ` [PATCH 2/2] bpf: Allow setting SO_TIMESTAMPING* with bpf_setsockopt() Jörn-Thorben Hinz
2023-07-03 21:25 ` John Fastabend [this message]
2023-07-04 16:11 ` [PATCH 0/2] bpf, net: Allow setting SO_TIMESTAMPING* from BPF Jörn-Thorben Hinz
2023-07-04 19:36 ` Willem de Bruijn
2023-07-04 20:26 ` Arnd Bergmann
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