Re: [PATCH bpf-next v10 5/5] selftests/bpf: Add mptcpify test

On 8/3/23 6:55 PM, 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

Ack with a minor nit below.

Acked-by: Yonghong Song yonghong.song@linux.dev

---

.../testing/selftests/bpf/prog_tests/mptcp.c | 88 +++++++++++++++++++ tools/testing/selftests/bpf/progs/mptcpify.c | 20 +++++ 2 files changed, 108 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 3dc0ba2e7590..e5ac2c3aab7d 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]; @@ -185,8 +186,95 @@ 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, 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;
  

• /* 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();

The above code essentially equals to err = verify_mptcpify() since err must be 0 before the above code. I think it is worthwhile to change the above to err = verify_mptcpify();

Otherwise, people may confuse that maybe err could be non-zero before send_byte(client_fd)? If this is the case, why we did not return earlier? The code err = verify_mptcpify() will make it clear that all previous error conditions have been handled properly.

• close(client_fd);

+close_server:

• close(server_fd);

+out:

• mptcpify__destroy(mptcpify_skel);
• return err;

+}

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