From: Jakub Sitnicki <jakub@cloudflare.com>
To: Stanislav Fomichev <sdf.kernel@gmail.com>
Cc: Willem Ferguson <wferguson@cloudflare.com>,
netdev@vger.kernel.org, davem@davemloft.net,
edumazet@kernel.org, kuba@kernel.org, pabeni@redhat.com,
ncardwell@google.com, bpf@vger.kernel.org, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com,
memxor@gmail.com, linux-doc@vger.kernel.org, corbet@lwn.net,
linux-kselftest@vger.kernel.org, shuah@kernel.org,
linux-kernel@vger.kernel.org, kernel-team@cloudflare.com
Subject: Re: [RFC PATCH net-next 0/4] tcp: carry a BPF-chosen identifier in TSval low bits
Date: Mon, 19 Oct 2026 11:20:24 +0200 [thread overview]
Message-ID: <87a4oaf3mv.fsf@cloudflare.com> (raw)
In-Reply-To: <atFI9vl5hy09Dc0t@devvm7509.cco0.facebook.com> (Stanislav Fomichev's message of "Thu, 15 Oct 2026 14:45:02 -0700")
Hey Stan,
On Thu, Oct 15, 2026 at 02:45 PM -07, Stanislav Fomichev wrote:
> On 10/13, Willem Ferguson wrote:
[...]
>> Questions for reviewers:
>>
>> 1. Is encoding an identifier in the low bits of TSval acceptable in
>> principle, given the trade-offs above?
>> 2. If so, what feedback do you have on the implementation?
>
> Don't see any feedback yet, so from the top of my head: looks like you
> control two sides of the communication, so why not a custom (bpf) tcp option?
> Would you need that on every packet and it makes it expensive?
>
> Or any other field you can abuse maybe? IPv6 Flow label?
Nah, we don't control the client unfortunately.
Client here is any device that connects to our edge PoP.
> Implementation-wise, the sock_ops is going away in favor of bpf_tcp_ops,
> so BPF_SOCK_OPS_TCP_TS_ID_CB_FLAG is a no go.
Yeah, we have just recently realized [1].
Thanks for feedback.
[1] https://lore.kernel.org/all/877bjk893u.fsf@cloudflare.com/
prev parent reply other threads:[~2026-10-19 9:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-13 10:39 [RFC PATCH net-next 0/4] tcp: carry a BPF-chosen identifier in TSval low bits Willem Ferguson
2026-10-13 10:39 ` [RFC PATCH net-next 1/4] tcp: add plumbing to carry an " Willem Ferguson
2026-10-13 10:39 ` [RFC PATCH net-next 2/4] tcp: add BPF_SOCK_OPS_TCP_TS_ID_CB to assign a TSval identifier Willem Ferguson
2026-10-14 17:50 ` Jakub Sitnicki
2026-10-15 12:12 ` Jason Xing
2026-10-13 10:39 ` [RFC PATCH net-next 3/4] tcp: add TCP_TS_ID socket option Willem Ferguson
2026-10-13 10:39 ` [RFC PATCH net-next 4/4] selftests/bpf: add tcp_ts_id test Willem Ferguson
2026-10-15 21:45 ` [RFC PATCH net-next 0/4] tcp: carry a BPF-chosen identifier in TSval low bits Stanislav Fomichev
2026-10-19 9:20 ` Jakub Sitnicki [this message]
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