Re: [PATCH bpf-next v3 5/5] selftests/bpf: Drop make_socket in sk_lookup

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

On 7/17/24 11:22 PM, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> Use local helper make_client() in drop_on_lookup(), drop_on_reuseport()
> and run_multi_prog_lookup() instead of using make_socket() + connect().
> Then make_socket() and inetaddr_len() can be dropped.
> 
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>   .../selftests/bpf/prog_tests/sk_lookup.c      | 58 ++-----------------
>   1 file changed, 6 insertions(+), 52 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
> index beea7866b37f..3d1c315841b7 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
> @@ -108,46 +108,6 @@ static int attach_reuseport(int sock_fd, struct bpf_program *reuseport_prog)
>   	return 0;
>   }
>   
> -static socklen_t inetaddr_len(const struct sockaddr_storage *addr)
> -{
> -	return (addr->ss_family == AF_INET ? sizeof(struct sockaddr_in) :
> -		addr->ss_family == AF_INET6 ? sizeof(struct sockaddr_in6) : 0);
> -}
> -
> -static int make_socket(int sotype, const char *ip, int port,
> -		       struct sockaddr_storage *addr)
> -{
> -	struct timeval timeo = { .tv_sec = IO_TIMEOUT_SEC };
> -	int err, family, fd;
> -
> -	family = is_ipv6(ip) ? AF_INET6 : AF_INET;
> -	err = make_sockaddr(family, ip, port, addr, NULL);
> -	if (CHECK(err, "make_address", "failed\n"))
> -		return -1;
> -
> -	fd = socket(addr->ss_family, sotype, 0);
> -	if (CHECK(fd < 0, "socket", "failed\n")) {
> -		log_err("failed to make socket");
> -		return -1;
> -	}
> -
> -	err = setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
> -	if (CHECK(err, "setsockopt(SO_SNDTIMEO)", "failed\n")) {
> -		log_err("failed to set SNDTIMEO");
> -		close(fd);
> -		return -1;
> -	}
> -
> -	err = setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeo, sizeof(timeo));
> -	if (CHECK(err, "setsockopt(SO_RCVTIMEO)", "failed\n")) {
> -		log_err("failed to set RCVTIMEO");
> -		close(fd);
> -		return -1;
> -	}
> -
> -	return fd;
> -}
> -
>   static int setsockopts(int fd, void *opts)
>   {
>   	struct cb_opts *co = (struct cb_opts *)opts;
> @@ -856,8 +816,7 @@ static void test_redirect_lookup(struct test_sk_lookup *skel)
>   
>   static void drop_on_lookup(const struct test *t)
>   {
> -	struct sockaddr_storage dst = {};
> -	int client_fd, server_fd, err;
> +	int client_fd, server_fd, err = 0;
>   	struct bpf_link *lookup_link;
>   	ssize_t n;
>   
> @@ -870,12 +829,11 @@ static void drop_on_lookup(const struct test *t)
>   	if (server_fd < 0)
>   		goto detach;
>   
> -	client_fd = make_socket(t->sotype, t->connect_to.ip,
> -				t->connect_to.port, &dst);
> +	client_fd = make_client(t->sotype, t->connect_to.ip,
> +				t->connect_to.port, ECONNREFUSED);
>   	if (client_fd < 0)
>   		goto close_srv;
>   
> -	err = connect(client_fd, (void *)&dst, inetaddr_len(&dst));
>   	if (t->sotype == SOCK_DGRAM) {
>   		err = send_byte(client_fd);
>   		if (err)
> @@ -970,7 +928,6 @@ static void test_drop_on_lookup(struct test_sk_lookup *skel)
>   
>   static void drop_on_reuseport(const struct test *t)
>   {
> -	struct sockaddr_storage dst = { 0 };
>   	int client, server1, server2, err;
>   	struct bpf_link *lookup_link;
>   	ssize_t n;
> @@ -994,12 +951,11 @@ static void drop_on_reuseport(const struct test *t)
>   	if (server2 < 0)
>   		goto close_srv1;
>   
> -	client = make_socket(t->sotype, t->connect_to.ip,
> -			     t->connect_to.port, &dst);
> +	client = make_client(t->sotype, t->connect_to.ip,
> +			     t->connect_to.port, ECONNREFUSED);
>   	if (client < 0)
>   		goto close_srv2;
>   
> -	err = connect(client, (void *)&dst, inetaddr_len(&dst));
>   	if (t->sotype == SOCK_DGRAM) {
>   		err = send_byte(client);
>   		if (err)
> @@ -1209,7 +1165,6 @@ struct test_multi_prog {
>   
>   static void run_multi_prog_lookup(const struct test_multi_prog *t)
>   {
> -	struct sockaddr_storage dst = {};
>   	int map_fd, server_fd, client_fd;
>   	struct bpf_link *link1, *link2;
>   	int prog_idx, done, err;
> @@ -1242,11 +1197,10 @@ static void run_multi_prog_lookup(const struct test_multi_prog *t)
>   	if (err)
>   		goto out_close_server;
>   
> -	client_fd = make_socket(SOCK_STREAM, EXT_IP4, EXT_PORT, &dst);
> +	client_fd = make_client(SOCK_STREAM, EXT_IP4, EXT_PORT, t->expect_errno);
>   	if (client_fd < 0)
>   		goto out_close_server;
>   
> -	err = connect(client_fd, (void *)&dst, inetaddr_len(&dst));
>   	if (CHECK(err && !t->expect_errno, "connect",

I haven't looked at the details in run_multi_prog_lookup(). I am quite sure this 
CHECK is wrong or at least unnecessary. "err" does not have the return value of 
connect() now but the t->expect_errno is for connect(), so what is the CHECK 
testing?

imo, burying the errno checking in make_client is confusing.

On top of removing make_socket, lets remove the make_client() also. Directly 
call connect_to_addr_str() instead. The caller of connect_to_addr_str() can 
handle the returned fd and errno. The drop_on_{lookup, reuseport} should handle 
them differently based on SOCK_STREAM or SOCK_DGRAM.

In the next respin, please take time to change the error handling properly after 
the refactoring/cleanup.

I am going to apply patch 1-3 with the small nits related to "log_err" in patch 2.