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From: Song Liu <liu.song.a23@gmail.com>
To: Stanislav Fomichev <sdf@google.com>
Cc: Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	"David S . Miller" <davem@davemloft.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Willem de Bruijn <willemb@google.com>,
	Petar Penkov <ppenkov@google.com>
Subject: Re: [PATCH bpf-next 2/7] bpf/flow_dissector: document flags
Date: Wed, 24 Jul 2019 15:24:29 -0700	[thread overview]
Message-ID: <CAPhsuW4rB3ZBrkCwo5yMHdSNNoE8qwho-5iTqR2cnN6HF76iEA@mail.gmail.com> (raw)
In-Reply-To: <20190724170018.96659-3-sdf@google.com>

On Wed, Jul 24, 2019 at 10:11 AM Stanislav Fomichev <sdf@google.com> wrote:
>
> Describe what each input flag does and who uses it.
>
> Cc: Willem de Bruijn <willemb@google.com>
> Cc: Petar Penkov <ppenkov@google.com>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>

Acked-by: Song Liu <songliubraving@fb.com>

> ---
>  Documentation/bpf/prog_flow_dissector.rst | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/Documentation/bpf/prog_flow_dissector.rst b/Documentation/bpf/prog_flow_dissector.rst
> index ed343abe541e..0f3f380b2ce4 100644
> --- a/Documentation/bpf/prog_flow_dissector.rst
> +++ b/Documentation/bpf/prog_flow_dissector.rst
> @@ -26,6 +26,7 @@ and output arguments.
>    * ``nhoff`` - initial offset of the networking header
>    * ``thoff`` - initial offset of the transport header, initialized to nhoff
>    * ``n_proto`` - L3 protocol type, parsed out of L2 header
> +  * ``flags`` - optional flags
>
>  Flow dissector BPF program should fill out the rest of the ``struct
>  bpf_flow_keys`` fields. Input arguments ``nhoff/thoff/n_proto`` should be
> @@ -101,6 +102,23 @@ can be called for both cases and would have to be written carefully to
>  handle both cases.
>
>
> +Flags
> +=====
> +
> +``flow_keys->flags`` might contain optional input flags that work as follows:
> +
> +* ``FLOW_DISSECTOR_F_PARSE_1ST_FRAG`` - tells BPF flow dissector to continue
> +  parsing first fragment; the default expected behavior is that flow dissector
> +  returns as soon as it finds out that the packet is fragmented;
> +  used by ``eth_get_headlen`` to estimate length of all headers for GRO.
> +* ``FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL`` - tells BPF flow dissector to stop
> +  parsing as soon as it reaches IPv6 flow label; used by ``___skb_get_hash``
> +  and ``__skb_get_hash_symmetric`` to get flow hash.
> +* ``FLOW_DISSECTOR_F_STOP_AT_ENCAP`` - tells BPF flow dissector to stop
> +  parsing as soon as it reaches encapsulated headers; used by routing
> +  infrastructure.
> +
> +
>  Reference Implementation
>  ========================
>
> --
> 2.22.0.657.g960e92d24f-goog
>

  reply	other threads:[~2019-07-24 22:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-24 17:00 [PATCH bpf-next 0/7] bpf/flow_dissector: support input flags Stanislav Fomichev
2019-07-24 17:00 ` [PATCH bpf-next 1/7] bpf/flow_dissector: pass input flags to BPF flow dissector program Stanislav Fomichev
2019-07-24 22:21   ` Song Liu
2019-07-24 22:32     ` Stanislav Fomichev
2019-07-24 22:45       ` Song Liu
2019-07-24 17:00 ` [PATCH bpf-next 2/7] bpf/flow_dissector: document flags Stanislav Fomichev
2019-07-24 22:24   ` Song Liu [this message]
2019-07-24 17:00 ` [PATCH bpf-next 3/7] bpf/flow_dissector: support flags in BPF_PROG_TEST_RUN Stanislav Fomichev
2019-07-24 22:33   ` Song Liu
2019-07-24 17:00 ` [PATCH bpf-next 4/7] tools/bpf: sync bpf_flow_keys flags Stanislav Fomichev
2019-07-24 23:17   ` Song Liu
2019-07-24 17:00 ` [PATCH bpf-next 5/7] sefltests/bpf: support FLOW_DISSECTOR_F_PARSE_1ST_FRAG Stanislav Fomichev
2019-07-24 23:21   ` Song Liu
2019-07-24 23:52     ` Stanislav Fomichev
2019-07-25  5:36       ` Song Liu
2019-07-24 17:00 ` [PATCH bpf-next 6/7] bpf/flow_dissector: support ipv6 flow_label and FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL Stanislav Fomichev
2019-07-24 23:28   ` Song Liu
2019-07-24 17:00 ` [PATCH bpf-next 7/7] selftests/bpf: support FLOW_DISSECTOR_F_STOP_AT_ENCAP Stanislav Fomichev
2019-07-24 23:29   ` Song Liu
2019-07-24 22:10 ` [PATCH bpf-next 0/7] bpf/flow_dissector: support input flags Willem de Bruijn

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