From: Mat Martineau <martineau@kernel.org>
To: Geliang Tang <geliang@kernel.org>
Cc: mptcp@lists.linux.dev, Geliang Tang <tanggeliang@kylinos.cn>
Subject: Re: [PATCH mptcp-next v6 6/8] selftests/bpf: Add mptcp subflow example
Date: Fri, 5 Apr 2024 17:36:46 -0700 (PDT) [thread overview]
Message-ID: <ca061adc-be94-b9a9-4c4c-72f8c311659f@kernel.org> (raw)
In-Reply-To: <1d61922711dc017c4cd323199fc5341908a40b69.1712042529.git.tanggeliang@kylinos.cn>
On Tue, 2 Apr 2024, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
>
> Move Nicolas's patch into bpf selftests directory. This example added a
> test that was adding a different mark (SO_MARK) on each subflow, and
> changing the TCP CC only on the first subflow.
>
> This example shows how it is possible to:
>
> Identify the parent msk of an MPTCP subflow.
> Put different sockopt for each subflow of a same MPTCP connection.
>
> Here especially, we implemented two different behaviours:
>
> A socket mark (SOL_SOCKET SO_MARK) is put on each subflow of a same
> MPTCP connection. The order of creation of the current subflow defines
> its mark. The TCP CC algorithm of the very first subflow of an MPTCP
> connection is set to "reno".
>
> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/76
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
> .../selftests/bpf/progs/mptcp_subflow.c | 73 +++++++++++++++++++
> 1 file changed, 73 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/mptcp_subflow.c
>
> diff --git a/tools/testing/selftests/bpf/progs/mptcp_subflow.c b/tools/testing/selftests/bpf/progs/mptcp_subflow.c
> new file mode 100644
> index 000000000000..9553099ffd5f
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/mptcp_subflow.c
> @@ -0,0 +1,73 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2020, Tessares SA. */
> +/* Copyright (c) 2024, Kylin Software */
> +/* Author: Nicolas Rybowski */
> +
> +#include <sys/socket.h> // SOL_SOCKET, SO_MARK, ...
> +#include <linux/tcp.h> // TCP_CONGESTION
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +#include "bpf_tcp_helpers.h"
> +
> +char _license[] SEC("license") = "GPL";
> +
> +#ifndef SOL_TCP
> +#define SOL_TCP 6
> +#endif
> +
> +#ifndef TCP_CA_NAME_MAX
> +#define TCP_CA_NAME_MAX 16
> +#endif
> +
> +char cc[TCP_CA_NAME_MAX] = "reno";
> +
> +/* Associate a subflow counter to each token */
> +struct {
> + __uint(type, BPF_MAP_TYPE_HASH);
> + __uint(key_size, sizeof(__u32));
> + __uint(value_size, sizeof(__u32));
> + __uint(max_entries, 100);
> +} mptcp_sf SEC(".maps");
> +
> +SEC("sockops")
> +int mptcp_subflow(struct bpf_sock_ops *skops)
> +{
> + __u32 init = 1, key, mark, *cnt;
> + struct mptcp_sock *msk;
> + struct bpf_sock *sk;
> + int err;
> +
> + if (skops->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
> + return 1;
> +
> + sk = skops->sk;
> + if (!sk)
> + return 1;
> +
> + msk = bpf_skc_to_mptcp_sock(sk);
> + if (!msk)
> + return 1;
> +
> + key = msk->token;
> + cnt = bpf_map_lookup_elem(&mptcp_sf, &key);
> + if (cnt) {
> + /* A new subflow is added to an existing MPTCP connection */
> + __sync_fetch_and_add(cnt, 1);
> + mark = *cnt;
> + } else {
> + /* A new MPTCP connection is just initiated and this is its primary
> + * subflow
> + */
> + bpf_map_update_elem(&mptcp_sf, &key, &init, BPF_ANY);
> + mark = init;
> + }
> +
> + /* Set the mark of the subflow's socket to its apparition order */
Hi Geliang -
I suggest updating Nicolas' phrasing here to instead say:
/* Set the mark of the subflow's socket based on appearance order */
"Apparition" means something different :)
Also, I couldn't get this series to apply to the export branch (or recent
export tags) even with the referenced bpf-next series and "refactor mptcp
bpf tests". When multiple series have dependencies, could you push a
branch to git.kernel.org and reference that in the cover letter?
Thanks,
- Mat
> + err = bpf_setsockopt(skops, SOL_SOCKET, SO_MARK, &mark, sizeof(mark));
> + if (err < 0)
> + return 1;
> + if (mark == 1)
> + err = bpf_setsockopt(skops, SOL_TCP, TCP_CONGESTION, cc, TCP_CA_NAME_MAX);
> +
> + return 1;
> +}
> --
> 2.40.1
>
>
>
next prev parent reply other threads:[~2024-04-06 0:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-02 7:24 [PATCH mptcp-next v6 0/8] setsockopt per subflow: BPF Geliang Tang
2024-04-02 7:24 ` [PATCH mptcp-next v6 1/8] Squash to "selftests/bpf: Add bpf scheduler test" 4 send_data Geliang Tang
2024-04-02 7:24 ` [PATCH mptcp-next v6 2/8] selftests/bpf: Handle SIGINT when creating netns Geliang Tang
2024-04-02 7:24 ` [PATCH mptcp-next v6 3/8] selftests/bpf: Refactor mptcp_sock test Geliang Tang
2024-04-02 7:24 ` [PATCH mptcp-next v6 4/8] selftests/bpf: Refactor mptcpify test Geliang Tang
2024-04-02 7:24 ` [PATCH mptcp-next v6 5/8] selftests/bpf: Add MPTCP_BASE_TEST macro Geliang Tang
2024-04-06 0:31 ` Mat Martineau
2024-04-02 7:24 ` [PATCH mptcp-next v6 6/8] selftests/bpf: Add mptcp subflow example Geliang Tang
2024-04-06 0:36 ` Mat Martineau [this message]
2024-04-02 7:24 ` [PATCH mptcp-next v6 7/8] selftests/bpf: Add mptcp subflow subtest Geliang Tang
2024-04-02 7:24 ` [PATCH mptcp-next v6 8/8] Squash to "selftests/bpf: Add bpf scheduler test" 5 endpoint_init Geliang Tang
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