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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Song Liu" <songliubraving@fb.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Martin Lau" <kafai@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"Marek Majkowski" <marek@cloudflare.com>,
	"Lorenz Bauer" <lmb@cloudflare.com>,
	"David Miller" <davem@davemloft.net>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next 0/9] xdp: Support multiple programs on a single interface through chain calls
Date: Thu, 3 Oct 2019 07:03:06 -0700	[thread overview]
Message-ID: <CAADnVQKTbaxJhkukxXM7Ue7=kA9eWsGMpnkXc=Z8O3iWGSaO0A@mail.gmail.com> (raw)
In-Reply-To: <20191003105335.3cc65226@carbon>

On Thu, Oct 3, 2019 at 1:53 AM Jesper Dangaard Brouer <brouer@redhat.com> wrote:
>> The xdpcap use-case is to trap any XDP return action code (and tcpdump
> via perf event ring_buffer).  For system administrators the xdpcap
> use-case is something we hear about all the time, so one of the missing
> features for XDP.  As Toke also wrote, we want to extend this to ALSO
> be-able to see/dump the packet BEFORE a given XDP program.

It sounds to me that 'xdpdump/xdpcap' (tcpdump equivalent) is
the only use case both you and Toke are advocating for.
I think such case we can do already without new kernel code:
- retrieve prog_id of the program attached to given xdp ifindex
- convert to fd
- create prog_array of one element and store that prog_fd
- create xdpump bpf prog that prints to ring buffer
  and tail_calls into that prog_array
- replace xdp prog on that ifindex

Now it see all the traffic first and existing xdp progs keep working.
What am I missing?

  reply	other threads:[~2019-10-03 14:03 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-02 13:30 [PATCH bpf-next 0/9] xdp: Support multiple programs on a single interface through chain calls Toke Høiland-Jørgensen
2019-10-02 13:30 ` [PATCH bpf-next 1/9] hashtab: Add new bpf_map_fd_put_value op Toke Høiland-Jørgensen
2019-10-02 13:30 ` [PATCH bpf-next 2/9] xdp: Add new xdp_chain_map type for specifying XDP call sequences Toke Høiland-Jørgensen
2019-10-02 15:50   ` Lorenz Bauer
2019-10-02 18:25     ` Toke Høiland-Jørgensen
2019-10-02 13:30 ` [PATCH bpf-next 3/9] xdp: Support setting and getting device chain map Toke Høiland-Jørgensen
2019-10-02 15:50   ` Lorenz Bauer
2019-10-02 18:32     ` Toke Høiland-Jørgensen
2019-10-02 18:07   ` kbuild test robot
2019-10-02 18:29   ` kbuild test robot
2019-10-02 13:30 ` [PATCH bpf-next 4/9] xdp: Implement chain call logic to support multiple programs on one interface Toke Høiland-Jørgensen
2019-10-02 17:33   ` kbuild test robot
2019-10-02 17:53   ` kbuild test robot
2019-10-02 13:30 ` [PATCH bpf-next 5/9] tools/include/uapi: Add XDP chain map definitions Toke Høiland-Jørgensen
2019-10-02 13:30 ` [PATCH bpf-next 6/9] tools/libbpf_probes: Add support for xdp_chain map type Toke Høiland-Jørgensen
2019-10-02 13:30 ` [PATCH bpf-next 7/9] bpftool: Add definitions " Toke Høiland-Jørgensen
2019-10-02 13:30 ` [PATCH bpf-next 8/9] libbpf: Add support for setting and getting XDP chain maps Toke Høiland-Jørgensen
2019-10-02 13:30 ` [PATCH bpf-next 9/9] selftests: Add tests for XDP chain calls Toke Høiland-Jørgensen
2019-10-02 15:10 ` [PATCH bpf-next 0/9] xdp: Support multiple programs on a single interface through " Alan Maguire
2019-10-02 15:33   ` Toke Høiland-Jørgensen
2019-10-02 16:34     ` John Fastabend
2019-10-02 18:33       ` Toke Høiland-Jørgensen
2019-10-02 20:34         ` John Fastabend
2019-10-03  7:48           ` Toke Høiland-Jørgensen
2019-10-03 10:09             ` Jesper Dangaard Brouer
2019-10-03 19:45               ` John Fastabend
2019-10-02 16:35 ` Lorenz Bauer
2019-10-02 18:54   ` Toke Høiland-Jørgensen
2019-10-02 16:43 ` John Fastabend
2019-10-02 19:09   ` Toke Høiland-Jørgensen
2019-10-02 19:15   ` Daniel Borkmann
2019-10-02 19:29     ` Toke Høiland-Jørgensen
2019-10-02 19:46     ` Alexei Starovoitov
2019-10-03  7:58       ` Toke Høiland-Jørgensen
2019-10-02 18:38 ` Song Liu
2019-10-02 18:54   ` Song Liu
2019-10-02 19:25     ` Toke Høiland-Jørgensen
2019-10-03  8:53       ` Jesper Dangaard Brouer
2019-10-03 14:03         ` Alexei Starovoitov [this message]
2019-10-03 14:33           ` Toke Høiland-Jørgensen
2019-10-03 14:53             ` Edward Cree
2019-10-03 18:49               ` Jesper Dangaard Brouer
2019-10-03 19:35               ` John Fastabend
2019-10-04  8:09                 ` Toke Høiland-Jørgensen
2019-10-04 10:34                   ` Edward Cree
2019-10-04 15:58                     ` Lorenz Bauer
2019-10-07 16:43                       ` Edward Cree
2019-10-07 17:12                         ` Lorenz Bauer
2019-10-07 19:21                           ` Edward Cree
2019-10-07 21:01                         ` Alexei Starovoitov
2019-10-02 19:23   ` Toke Høiland-Jørgensen
2019-10-02 19:49     ` Song Liu
2019-10-03  7:59       ` Toke Høiland-Jørgensen

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