Re: [PATCH bpf-next v9 4/4] selftests/bpf: Add mptcpify test

On 8/3/23 6:41 AM, Geliang Tang wrote:

Implement a new test program mptcpify: if the family is AF_INET or AF_INET6, the type is SOCK_STREAM, and the protocol ID is 0 or IPPROTO_TCP, set it to IPPROTO_MPTCP. It will be hooked in update_socket_protocol().

Extend the MPTCP test base, add a selftest test_mptcpify() for the mptcpify case. Open and load the mptcpify test prog to mptcpify the TCP sockets dynamically, then use start_server() and connect_to_fd() to create a TCP socket, but actually what's created is an MPTCP socket, which can be verified through the outputs of 'ss' and 'nstat' commands.

Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Geliang Tang geliang.tang@suse.com

---

.../testing/selftests/bpf/prog_tests/mptcp.c | 94 +++++++++++++++++++ tools/testing/selftests/bpf/progs/mptcpify.c | 25 +++++ 2 files changed, 119 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/mptcpify.c

diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c index 4407bd5c9e9a..caab3aa6a162 100644 --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c @@ -6,6 +6,7 @@ #include "cgroup_helpers.h" #include "network_helpers.h" #include "mptcp_sock.skel.h" +#include "mptcpify.skel.h" char NS_TEST[32]; @@ -195,8 +196,101 @@ static void test_base(void) close(cgroup_fd); } +static void send_byte(int fd) +{

• char b = 0x55;
• ASSERT_EQ(write(fd, &b, sizeof(b)), 1, "send single byte");

+}

+static int verify_mptcpify(void) +{

• char cmd[256];
• int err = 0;
• snprintf(cmd, sizeof(cmd),

•  "ip netns exec %s ss -tOni | grep -q '%s'",
  

•  NS_TEST, "tcp-ulp-mptcp");
  

• if (!ASSERT_OK(system(cmd), "No tcp-ulp-mptcp found!"))

• err++;
  

• snprintf(cmd, sizeof(cmd),

•  "ip netns exec %s nstat -asz %s | awk '%s' | grep -q '%s'",
  

•  NS_TEST, "MPTcpExtMPCapableSYNACKRX",
  

•  "NR==1 {next} {print $2}", "1");
  

• if (!ASSERT_OK(system(cmd), "No MPTcpExtMPCapableSYNACKRX found!"))

• err++;
  

• return err;

+}

+static int run_mptcpify(int cgroup_fd) +{

• int server_fd, client_fd, prog_fd, err = 0;
• struct mptcpify *mptcpify_skel;
• mptcpify_skel = mptcpify__open_and_load();
• if (!ASSERT_OK_PTR(mptcpify_skel, "skel_open_load"))

• return -EIO;
  

• err = mptcpify__attach(mptcpify_skel);
• if (!ASSERT_OK(err, "skel_attach"))

• goto out;
  

• prog_fd = bpf_program__fd(mptcpify_skel->progs.mptcpify);
• if (!ASSERT_GE(prog_fd, 0, "bpf_program__fd")) {

• err = -EIO;
  

• goto out;
  

• }

load success means prog_fd is always valid. So above ASSERT_GE not needed.

• /* without MPTCP */
• server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0);
• if (!ASSERT_GE(server_fd, 0, "start_server")) {

• err = -EIO;
  

• goto out;
  

• }
• client_fd = connect_to_fd(server_fd, 0);
• if (!ASSERT_GE(client_fd, 0, "connect to fd")) {

• err = -EIO;
  

• goto close_server;
  

• }
• send_byte(client_fd);
• err += verify_mptcpify();
• close(client_fd);

+close_server:

• close(server_fd);

+out:

• mptcpify__destroy(mptcpify_skel);
• return err;

+}

+static void test_mptcpify(void) +{

• struct nstoken *nstoken = NULL;
• int cgroup_fd;
• cgroup_fd = test__join_cgroup("/mptcpify");
• if (!ASSERT_GE(cgroup_fd, 0, "test__join_cgroup"))

• return;
  

• nstoken = create_netns();
• if (!ASSERT_OK_PTR(nstoken, "create_netns"))

• goto fail;
  

• ASSERT_OK(run_mptcpify(cgroup_fd), "run_mptcpify");

+fail:

• cleanup_netns(nstoken);
• close(cgroup_fd);

+}

• void test_mptcp(void) { if (test__start_subtest("base")) test_base();
• if (test__start_subtest("mptcpify"))

• test_mptcpify();
  

  }

diff --git a/tools/testing/selftests/bpf/progs/mptcpify.c b/tools/testing/selftests/bpf/progs/mptcpify.c new file mode 100644 index 000000000000..9cf1febe982d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/mptcpify.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023, SUSE. */

+#include <linux/bpf.h> +#include <bpf/bpf_tracing.h>

+char _license[] SEC("license") = "GPL";

+#define AF_INET 2 +#define AF_INET6 10 +#define SOCK_STREAM 1 +#define IPPROTO_TCP 6 +#define IPPROTO_MPTCP 262

To avoid the above macros, you can use vmlinux.h and bpf_tracing_net.h.

+SEC("fmod_ret/update_socket_protocol") +int BPF_PROG(mptcpify, int family, int type, int protocol) +{

• if ((family == AF_INET || family == AF_INET6) &&

•    type == SOCK_STREAM &&
  

•    (!protocol || protocol == IPPROTO_TCP)) {
  

• return IPPROTO_MPTCP;
  

• }
• return protocol;

+}