Re: [PATCH bpf-next v11 5/5] selftests/bpf: Add mptcpify test

Martin KaFai Lau
2023-08-05T00:40:23Z

On 8/3/23 10:07 PM, Geliang Tang wrote:
> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> index 3dc0ba2e7590..e6aafb4cfa8e 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 +186,105 @@ 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;
> +
> + /* Output of ss:
> + *
> + * ESTAB 0 0 127.0.0.1:44180 127.0.0.1:42225 cubic
> + * ... tcp-ulp-mptcp flags:Mmec ...
> + */
> + 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++;
> +
> + /* Output of nstat:
> + *
> + * #kernel
> + * MPTcpExtMPCapableSYNACKRX 1 0.0
> + */
> + 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++;

The idea is to confirm the protocol has been changed. Is it more direct to use
getsockopt(SO_PROTOCOL) on the created fd(s)?

> +
> + 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;

Although the return value does not matter much, -EIO looks weird for the error
from mptcpify__open_and_load(). May be 'return libbpf_get_error(mptcpify_skel);'

--
pw-bot: cr

> +
> + 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();
> +
> + close(client_fd);
> +close_server:
> + close(server_fd);
> +out:
> + mptcpify__destroy(mptcpify_skel);
> + return err;
> +}
> +