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From: Eric Dumazet <edumazet@google.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	kernel-team <kernel-team@fb.com>, Lawrence Brakmo <brakmo@fb.com>,
	Neal Cardwell <ncardwell@google.com>,
	netdev <netdev@vger.kernel.org>,
	Yuchung Cheng <ycheng@google.com>
Subject: Re: [PATCH bpf-next 01/10] tcp: Use a struct to represent a saved_syn
Date: Tue, 30 Jun 2020 16:35:20 -0700	[thread overview]
Message-ID: <CANn89iKj-okNmJhUnOmzdGVbOHi8zdF+=oO4RUFOo2X6M1kZHw@mail.gmail.com> (raw)
In-Reply-To: <20200630232406.3ozanjlyx5a2mv6i@kafai-mbp.dhcp.thefacebook.com>

On Tue, Jun 30, 2020 at 4:24 PM Martin KaFai Lau <kafai@fb.com> wrote:

> Interesting idea.  I don't have an immediate use case in the mac header of
> the SYN but I think it may be useful going forward.
>
> Although bpf_hdr_opt_off may be no longer needed in v2,
> it will still be convenient for the bpf prog to be able to get the TCP header
> only instead of reparsing from the mac/ip[46] and also save some stack space
> of the bpf prog.  Thus, storing the length of each hdr would still be nice
> so that the bpf helper can directly offset to the start of the required
> header.
>
> Do you prefer to incorporate this "save_syn:2" idea in this set
> so that mac hdrlen can be stored in the "struct saved_syn"?

Sure, please go ahead.

>
> This "unused:2" bits have already been used by "fastopen_client_fail:2".

Oh that is possible, I have sent the patch as it was when we merged it
years ago.

> May be get 2 bits from repair_queue?

Hmm... this repair_queue is used in fast path, I would rather keep it
as u8 for better code generation.

  reply	other threads:[~2020-06-30 23:35 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-26 17:55 [PATCH bpf-next 00/10] BPF TCP header options Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 01/10] tcp: Use a struct to represent a saved_syn Martin KaFai Lau
2020-06-27 17:41   ` Eric Dumazet
2020-06-30 23:24     ` Martin KaFai Lau
2020-06-30 23:35       ` Eric Dumazet [this message]
2020-06-26 17:55 ` [PATCH bpf-next 02/10] tcp: bpf: Parse BPF experimental header option Martin KaFai Lau
2020-06-27 16:44   ` Eric Dumazet
2020-06-27 17:17   ` Eric Dumazet
2020-06-28 23:44     ` Martin KaFai Lau
2020-06-29  0:45     ` Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 03/10] bpf: sock_ops: Change some members of sock_ops_kern from u32 to u8 Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 04/10] bpf: tcp: Allow bpf prog to write and parse BPF TCP header option Martin KaFai Lau
2020-06-28 18:24   ` Alexei Starovoitov
2020-06-29  0:34     ` Martin KaFai Lau
2020-07-02  5:31       ` Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 05/10] bpf: selftests: A few improvements to network_helpers.c Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 06/10] bpf: selftests: Add fastopen_connect to network_helpers Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 07/10] bpf: selftests: Restore netns after each test Martin KaFai Lau
2020-06-26 22:45   ` Andrii Nakryiko
2020-06-27  0:23     ` Martin KaFai Lau
2020-06-27 20:31       ` Andrii Nakryiko
2020-06-29 18:00         ` Martin KaFai Lau
2020-06-29 18:13           ` Andrii Nakryiko
2020-06-29 18:24             ` Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 08/10] bpf: selftests: tcp header options Martin KaFai Lau
2020-06-26 17:55 ` [PATCH bpf-next 09/10] tcp: bpf: Add TCP_BPF_DELACK_MAX and TCP_BPF_RTO_MIN to bpf_setsockopt Martin KaFai Lau
2020-06-27 17:30   ` Eric Dumazet
2020-06-26 17:56 ` [PATCH bpf-next 10/10] bpf: selftest: Add test for TCP_BPF_DELACK_MAX and TCP_BPF_RTO_MIN Martin KaFai Lau

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