Re: [PATCH bpf-next v5 6/7] selftests/bpf: Use connect_to_fd_opts in do_test in bpf_tcp_ca

[Martin KaFai Lau <martin.lau@linux.dev>]

On 5/25/24 5:08 AM, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> This patch uses connect_to_fd_opts() instead of using connect_fd_to_fd()
> and settcpca() in do_test() in prog_tests/bpf_tcp_ca.c to accept a struct
> network_helper_opts argument.
> 
> Then define a dctcp dedicated post_socket_cb callback stg_post_socket_cb(),
> invoking both cc_cb() and bpf_map_update_elem() in it, and set it in
> test_dctcp(). For passing map_fd into stg_post_socket_cb() callback, a new
> member map_fd is added in struct cb_opts.
> 
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>   .../selftests/bpf/prog_tests/bpf_tcp_ca.c     | 42 ++++++++++---------
>   1 file changed, 22 insertions(+), 20 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> index ebc7d4616880..9a7c3dc39008 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> @@ -25,6 +25,7 @@ static int expected_stg = 0xeB9F;
>   
>   struct cb_opts {
>   	const char *cc;
> +	int map_fd;
>   };
>   
>   static int settcpca(int fd, const char *tcp_ca)
> @@ -41,7 +42,6 @@ static int settcpca(int fd, const char *tcp_ca)
>   static void do_test(const struct network_helper_opts *opts,
>   		    const struct bpf_map *sk_stg_map)
>   {
> -	struct cb_opts *cb_opts = (struct cb_opts *)opts->cb_opts;
>   	int lfd = -1, fd = -1;
>   	int err;
>   
> @@ -49,25 +49,9 @@ static void do_test(const struct network_helper_opts *opts,
>   	if (!ASSERT_NEQ(lfd, -1, "socket"))
>   		return;
>   
> -	fd = socket(AF_INET6, SOCK_STREAM, 0);
> -	if (!ASSERT_NEQ(fd, -1, "socket")) {
> -		close(lfd);
> -		return;
> -	}
> -
> -	if (settcpca(fd, cb_opts->cc))
> -		goto done;
> -
> -	if (sk_stg_map) {
> -		err = bpf_map_update_elem(bpf_map__fd(sk_stg_map), &fd,
> -					  &expected_stg, BPF_NOEXIST);
> -		if (!ASSERT_OK(err, "bpf_map_update_elem(sk_stg_map)"))
> -			goto done;
> -	}
> -
>   	/* connect to server */
> -	err = connect_fd_to_fd(fd, lfd, 0);
> -	if (!ASSERT_NEQ(err, -1, "connect"))
> +	fd = connect_to_fd_opts(lfd, opts);
> +	if (!ASSERT_NEQ(fd, -1, "connect_to_fd_opts"))
>   		goto done;
>   
>   	if (sk_stg_map) {
> @@ -124,13 +108,30 @@ static void test_cubic(void)
>   	bpf_cubic__destroy(cubic_skel);
>   }
>   
> +static int stg_post_socket_cb(int fd, void *opts)
> +{
> +	struct cb_opts *cb_opts = (struct cb_opts *)opts;
> +	int err;
> +
> +	err = settcpca(fd, cb_opts->cc);
> +	if (err)
> +		return err;
> +
> +	err = bpf_map_update_elem(cb_opts->map_fd, &fd,
> +				  &expected_stg, BPF_NOEXIST);

Looking at it again, it is not very correct. At least this map update is 
unnecessary for the start_server_str() in do_test(). do_test() uses the same 
opts for start_server_str() and connect_to_fd_opts().

Also, the post_connect_cb in patch 8 is unnecessary for network_helpers.c. The 
connect_to_fd_opts helper is going to return the fd anyway. It is unnecessary to 
have the helper to do the post_connect_cb(fd). The caller (do_test here) can 
directly do that instead. Lets not add unnecessary post_connect_cb to the 
network_helpers.c now until there is a clear case that the caller cannot do it.

I would just add another "const struct network_helper_opts *cli_opts" to the
do_test() to do what patch 7 and patch 8 need to do. Separate it from the server 
"opts".

Patach 1 to 5 is applied. Thanks.


> +	if (!ASSERT_OK(err, "bpf_map_update_elem(sk_stg_map)"))
> +		return err;
> +
> +	return 0;
> +}
> +
>   static void test_dctcp(void)
>   {
>   	struct cb_opts cb_opts = {
>   		.cc = "bpf_dctcp",
>   	};
>   	struct network_helper_opts opts = {
> -		.post_socket_cb	= cc_cb,
> +		.post_socket_cb	= stg_post_socket_cb,
>   		.cb_opts	= &cb_opts,
>   	};
>   	struct bpf_dctcp *dctcp_skel;
> @@ -146,6 +147,7 @@ static void test_dctcp(void)
>   		return;
>   	}
>   
> +	cb_opts.map_fd = bpf_map__fd(dctcp_skel->maps.sk_stg_map);
>   	do_test(&opts, dctcp_skel->maps.sk_stg_map);
>   	ASSERT_EQ(dctcp_skel->bss->stg_result, expected_stg, "stg_result");
>