From: Jakub Sitnicki <jakub@cloudflare.com>
To: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: mptcp@lists.linux.dev, netdev@vger.kernel.org,
bpf@vger.kernel.org, John Fastabend <john.fastabend@gmail.com>,
Eric Dumazet <edumazet@google.com>,
Kuniyuki Iwashima <kuniyu@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Willem de Bruijn <willemb@google.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Simon Horman <horms@kernel.org>,
Matthieu Baerts <matttbe@kernel.org>,
Mat Martineau <martineau@kernel.org>,
Geliang Tang <geliang@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>,
Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
Shuah Khan <shuah@kernel.org>, Florian Westphal <fw@strlen.de>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH net v2 3/3] selftests/bpf: Add mptcp test with sockmap
Date: Thu, 23 Oct 2025 12:18:42 +0200 [thread overview]
Message-ID: <87v7k5vs3h.fsf@cloudflare.com> (raw)
In-Reply-To: <20251020060503.325369-4-jiayuan.chen@linux.dev> (Jiayuan Chen's message of "Mon, 20 Oct 2025 14:04:48 +0800")
On Mon, Oct 20, 2025 at 02:04 PM +08, Jiayuan Chen wrote:
> Add test cases to verify that when MPTCP falls back to plain TCP sockets,
> they can properly work with sockmap.
>
> Additionally, add test cases to ensure that sockmap correctly rejects
> MPTCP sockets as expected.
>
> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
> ---
> .../testing/selftests/bpf/prog_tests/mptcp.c | 136 ++++++++++++++++++
> .../selftests/bpf/progs/mptcp_sockmap.c | 43 ++++++
> 2 files changed, 179 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/mptcp_sockmap.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> index f8eb7f9d4fd2..54459b385439 100644
> --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> @@ -6,11 +6,14 @@
> #include <netinet/in.h>
> #include <test_progs.h>
> #include <unistd.h>
> +#include <error.h>
> #include "cgroup_helpers.h"
> #include "network_helpers.h"
> +#include "socket_helpers.h"
> #include "mptcp_sock.skel.h"
> #include "mptcpify.skel.h"
> #include "mptcp_subflow.skel.h"
> +#include "mptcp_sockmap.skel.h"
>
> #define NS_TEST "mptcp_ns"
> #define ADDR_1 "10.0.1.1"
> @@ -436,6 +439,137 @@ static void test_subflow(void)
> close(cgroup_fd);
> }
>
> +/* Test sockmap on MPTCP server handling non-mp-capable clients. */
> +static void test_sockmap_with_mptcp_fallback(struct mptcp_sockmap *skel)
> +{
> + int listen_fd = -1, client_fd1 = -1, client_fd2 = -1;
> + int server_fd1 = -1, server_fd2 = -1, sent, recvd;
> + char snd[9] = "123456789";
> + char rcv[10];
> +
> + listen_fd = start_mptcp_server(AF_INET, NULL, 0, 0);
> + if (!ASSERT_OK_FD(listen_fd, "redirect:start_mptcp_server"))
> + return;
> +
> + skel->bss->trace_port = ntohs(get_socket_local_port(listen_fd));
> + skel->bss->sk_index = 0;
> + client_fd1 = connect_to_fd_opts(listen_fd, NULL);
> + if (!ASSERT_OK_FD(client_fd1, "redirect:connect_to_fd"))
> + goto end;
> + server_fd1 = xaccept_nonblock(listen_fd, NULL, NULL);
> + skel->bss->sk_index = 1;
> + client_fd2 = connect_to_fd_opts(listen_fd, NULL);
> + if (!ASSERT_OK_FD(client_fd2, "redirect:connect_to_fd"))
> + goto end;
> + server_fd1 = xaccept_nonblock(listen_fd, NULL, NULL);
> + /* test normal redirect behavior: the data sent by client_fd1 can be
> + * received by client_fd2
> + */
> + skel->bss->redirect_idx = 1;
> + sent = xsend(client_fd1, snd, sizeof(snd), 0);
> + if (!ASSERT_EQ(sent, sizeof(snd), "redirect:xsend(client_fd1)"))
> + goto end;
> +
> + /* try to recv more byte to avoid truncation check */
> + recvd = recv_timeout(client_fd2, rcv, sizeof(rcv), MSG_DONTWAIT, 2);
> + if (!ASSERT_EQ(recvd, sizeof(snd), "redirect:recv(client_fd2)"))
> + goto end;
> +
> +end:
> + if (client_fd1 > 1)
> + close(client_fd1);
> + if (client_fd2 > 1)
> + close(client_fd2);
> + if (server_fd1 > 0)
> + close(server_fd1);
> + if (server_fd2 > 0)
> + close(server_fd2);
> + close(listen_fd);
> +}
> +
> +static void test_sockmap_reject_mptcp(struct mptcp_sockmap *skel)
> +{
> + int listen_fd = -1, server_fd = -1;
> + int client_fd1 = -1, client_fd2 = -1;
> + int err, zero = 0;
> +
> + listen_fd = start_mptcp_server(AF_INET, NULL, 0, 0);
> + if (!ASSERT_OK_FD(listen_fd, "start_mptcp_server"))
> + return;
> +
> + skel->bss->trace_port = ntohs(get_socket_local_port(listen_fd));
> + skel->bss->sk_index = 0;
> + client_fd1 = connect_to_fd(listen_fd, 0);
> + if (!ASSERT_OK_FD(client_fd1, "connect_to_fd client_fd1"))
> + goto end;
> + /* sockmap helper called from sockops prog should reject mptcp sk */
> + if (ASSERT_EQ(skel->bss->helper_ret, -EOPNOTSUPP, "should reject"))
> + goto end;
I'm confused. Should we bail out (goto end) if EOPNOTSUPP is *not*
returned? That is "if (!ASSERT_EQ(...))".
> +
> + /* skip sockops prog */
> + skel->bss->trace_port = -1;
> + client_fd2 = connect_to_fd(listen_fd, 0);
> + if (!ASSERT_OK_FD(client_fd2, "connect_to_fd client_fd2"))
> + goto end;
> +
> + server_fd = xaccept_nonblock(listen_fd, NULL, NULL);
> + err = bpf_map_update_elem(bpf_map__fd(skel->maps.sock_map),
> + &zero, &server_fd, BPF_NOEXIST);
> + if (ASSERT_EQ(err, -EOPNOTSUPP, "should reject"))
> + goto end;
Same here. The check seems backward.
> +end:
> + if (client_fd1 > 0)
> + close(client_fd1);
> + if (client_fd2 > 0)
> + close(client_fd2);
> + if (server_fd > 0)
> + close(server_fd);
> + close(listen_fd);
> +}
> +
> +static void test_mptcp_sockmap(void)
> +{
> + struct mptcp_sockmap *skel;
> + struct netns_obj *netns;
> + int cgroup_fd, err;
> +
> + cgroup_fd = test__join_cgroup("/mptcp_sockmap");
> + if (!ASSERT_OK_FD(cgroup_fd, "join_cgroup: mptcp_sockmap"))
> + return;
> +
> + skel = mptcp_sockmap__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "skel_open_load: mptcp_sockmap"))
> + goto close_cgroup;
> +
> + skel->links.mptcp_sockmap_inject =
> + bpf_program__attach_cgroup(skel->progs.mptcp_sockmap_inject, cgroup_fd);
> + if (!ASSERT_OK_PTR(skel->links.mptcp_sockmap_inject, "attach sockmap"))
> + goto skel_destroy;
> +
> + err = bpf_prog_attach(bpf_program__fd(skel->progs.mptcp_sockmap_redirect),
> + bpf_map__fd(skel->maps.sock_map),
> + BPF_SK_SKB_STREAM_VERDICT, 0);
> + if (!ASSERT_OK(err, "bpf_prog_attach stream verdict"))
> + goto skel_destroy;
> +
> + netns = netns_new(NS_TEST, true);
> + if (!ASSERT_OK_PTR(netns, "netns_new: mptcp_sockmap"))
> + goto skel_destroy;
> +
> + if (endpoint_init("subflow") < 0)
> + goto close_netns;
> +
> + test_sockmap_with_mptcp_fallback(skel);
> + test_sockmap_reject_mptcp(skel);
> +
> +close_netns:
> + netns_free(netns);
> +skel_destroy:
> + mptcp_sockmap__destroy(skel);
> +close_cgroup:
> + close(cgroup_fd);
> +}
> +
> void test_mptcp(void)
> {
> if (test__start_subtest("base"))
> @@ -444,4 +578,6 @@ void test_mptcp(void)
> test_mptcpify();
> if (test__start_subtest("subflow"))
> test_subflow();
> + if (test__start_subtest("sockmap"))
> + test_mptcp_sockmap();
> }
> diff --git a/tools/testing/selftests/bpf/progs/mptcp_sockmap.c b/tools/testing/selftests/bpf/progs/mptcp_sockmap.c
> new file mode 100644
> index 000000000000..d4eef0cbadb9
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/mptcp_sockmap.c
> @@ -0,0 +1,43 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include "bpf_tracing_net.h"
> +
> +char _license[] SEC("license") = "GPL";
> +
> +int sk_index;
> +int redirect_idx;
> +int trace_port;
> +int helper_ret;
> +struct {
> + __uint(type, BPF_MAP_TYPE_SOCKMAP);
> + __uint(key_size, sizeof(__u32));
> + __uint(value_size, sizeof(__u32));
> + __uint(max_entries, 100);
> +} sock_map SEC(".maps");
> +
> +SEC("sockops")
> +int mptcp_sockmap_inject(struct bpf_sock_ops *skops)
> +{
> + struct bpf_sock *sk;
> +
> + /* only accept specified connection */
> + if (skops->local_port != trace_port ||
> + skops->op != BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)
> + return 1;
> +
> + sk = skops->sk;
> + if (!sk)
> + return 1;
> +
> + /* update sk handler */
> + helper_ret = bpf_sock_map_update(skops, &sock_map, &sk_index, BPF_NOEXIST);
> +
> + return 1;
> +}
> +
> +SEC("sk_skb/stream_verdict")
> +int mptcp_sockmap_redirect(struct __sk_buff *skb)
> +{
> + /* redirect skb to the sk under sock_map[redirect_idx] */
> + return bpf_sk_redirect_map(skb, &sock_map, redirect_idx, 0);
> +}
prev parent reply other threads:[~2025-10-23 10:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-20 6:04 [PATCH net v2 0/3] mptcp: Fix conflicts between MPTCP and sockmap Jiayuan Chen
2025-10-20 6:04 ` [PATCH net v2 1/3] net,mptcp: fix incorrect IPv4/IPv6 fallback detection with BPF Sockmap Jiayuan Chen
2025-10-21 10:24 ` Jakub Sitnicki
2025-10-20 6:04 ` [PATCH net v2 2/3] bpf,sockmap: disallow MPTCP sockets from sockmap updates Jiayuan Chen
2025-10-21 10:49 ` Jakub Sitnicki
2025-10-21 12:16 ` Jiayuan Chen
2025-10-20 6:04 ` [PATCH net v2 3/3] selftests/bpf: Add mptcp test with sockmap Jiayuan Chen
2025-10-23 10:18 ` Jakub Sitnicki [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87v7k5vs3h.fsf@cloudflare.com \
--to=jakub@cloudflare.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=eddyz87@gmail.com \
--cc=edumazet@google.com \
--cc=fw@strlen.de \
--cc=geliang@kernel.org \
--cc=haoluo@google.com \
--cc=horms@kernel.org \
--cc=jiayuan.chen@linux.dev \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=kpsingh@kernel.org \
--cc=kuba@kernel.org \
--cc=kuniyu@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=martin.lau@linux.dev \
--cc=martineau@kernel.org \
--cc=matttbe@kernel.org \
--cc=mptcp@lists.linux.dev \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=sdf@fomichev.me \
--cc=shuah@kernel.org \
--cc=song@kernel.org \
--cc=willemb@google.com \
--cc=yonghong.song@linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).