From: Eric Dumazet <edumazet@google.com>
To: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Kuniyuki Iwashima <kuni1840@gmail.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v6 bpf-next 1/6] tcp: Move tcp_ns_to_ts() to tcp.h
Date: Thu, 14 Dec 2023 17:17:10 +0100 [thread overview]
Message-ID: <CANn89iJS+rGAWaDCsOXmyrXF0d_xSXqrFXpknAnPMZAQ5mi43g@mail.gmail.com> (raw)
In-Reply-To: <20231214155424.67136-2-kuniyu@amazon.com>
On Thu, Dec 14, 2023 at 4:55 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote:
>
> We will support arbitrary SYN Cookie with BPF.
>
> When BPF prog validates ACK and kfunc allocates a reqsk, we need
> to call tcp_ns_to_ts() to calculate an offset of TSval for later
> use:
>
> time
> t0 : Send SYN+ACK
> -> tsval = Initial TSval (Random Number)
>
> t1 : Recv ACK of 3WHS
> -> tsoff = TSecr - tcp_ns_to_ts(usec_ts_ok, tcp_clock_ns())
> = Initial TSval - t1
>
> t2 : Send ACK
> -> tsval = t2 + tsoff
> = Initial TSval + (t2 - t1)
> = Initial TSval + Time Delta (x)
>
> (x) Note that the time delta does not include the initial RTT
> from t0 to t1.
>
> Let's move tcp_ns_to_ts() to tcp.h.
>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
next prev parent reply other threads:[~2023-12-14 16:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-14 15:54 [PATCH v6 bpf-next 0/6] bpf: tcp: Support arbitrary SYN Cookie at TC Kuniyuki Iwashima
2023-12-14 15:54 ` [PATCH v6 bpf-next 1/6] tcp: Move tcp_ns_to_ts() to tcp.h Kuniyuki Iwashima
2023-12-14 16:17 ` Eric Dumazet [this message]
2023-12-14 15:54 ` [PATCH v6 bpf-next 2/6] tcp: Move skb_steal_sock() to request_sock.h Kuniyuki Iwashima
2023-12-14 16:20 ` Eric Dumazet
2023-12-14 15:54 ` [PATCH v6 bpf-next 3/6] bpf: tcp: Handle BPF SYN Cookie in skb_steal_sock() Kuniyuki Iwashima
2023-12-14 16:31 ` Eric Dumazet
2023-12-15 2:37 ` Kuniyuki Iwashima
2023-12-19 16:45 ` Mat Martineau
2023-12-20 10:22 ` Paolo Abeni
2023-12-21 0:58 ` Kuniyuki Iwashima
2023-12-14 15:54 ` [PATCH v6 bpf-next 4/6] bpf: tcp: Handle BPF SYN Cookie in cookie_v[46]_check() Kuniyuki Iwashima
2023-12-14 15:54 ` [PATCH v6 bpf-next 5/6] bpf: tcp: Support arbitrary SYN Cookie Kuniyuki Iwashima
2023-12-14 15:54 ` [PATCH v6 bpf-next 6/6] selftest: bpf: Test bpf_sk_assign_tcp_reqsk() Kuniyuki Iwashima
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