selftests/bpf: Add client_socket helper

This patch extracts a new helper client_socket() from connect_to_fd_opts()
to create the client socket, but don't connect to the server. Then
connect_to_fd_opts() can be implemented using client_socket() and
connect_fd_to_addr(). This helper can be used in connect_to_addr() too,
and make "noconnect" opts useless.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/4169c554e1cee79223feea49a1adc459d55e1ffe.1718932493.git.tanggeliang@kylinos.cnSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/network_helpers.c

@@ -249,6 +249,34 @@ int fastopen_connect(int server_fd, const char *data, unsigned int data_len,
 	return -1;
 }
 
+int client_socket(int family, int type,
+		  const struct network_helper_opts *opts)
+{
+	int fd;
+
+	if (!opts)
+		opts = &default_opts;
+
+	fd = socket(family, type, opts->proto);
+	if (fd < 0) {
+		log_err("Failed to create client socket");
+		return -1;
+	}
+
+	if (settimeo(fd, opts->timeout_ms))
+		goto error_close;
+
+	if (opts->post_socket_cb &&
+	    opts->post_socket_cb(fd, opts->cb_opts))
+		goto error_close;
+
+	return fd;
+
+error_close:
+	save_errno_close(fd);
+	return -1;
+}
+
 static int connect_fd_to_addr(int fd,
 			      const struct sockaddr_storage *addr,
 			      socklen_t addrlen, const bool must_fail)
@@ -284,19 +312,12 @@ int connect_to_addr(int type, const struct sockaddr_storage *addr, socklen_t add
 	if (!opts)
 		opts = &default_opts;
 
-	fd = socket(addr->ss_family, type, opts->proto);
+	fd = client_socket(addr->ss_family, type, opts);
 	if (fd < 0) {
 		log_err("Failed to create client socket");
 		return -1;
 	}
 
-	if (settimeo(fd, opts->timeout_ms))
-		goto error_close;
-
-	if (opts->post_socket_cb &&
-	    opts->post_socket_cb(fd, opts->cb_opts))
-		goto error_close;
-
 	if (!opts->noconnect)
 		if (connect_fd_to_addr(fd, addr, addrlen, opts->must_fail))
 			goto error_close;

tools/testing/selftests/bpf/network_helpers.h

@@ -57,6 +57,8 @@ int *start_reuseport_server(int family, int type, const char *addr_str,
 int start_server_addr(int type, const struct sockaddr_storage *addr, socklen_t len,
 		      const struct network_helper_opts *opts);
 void free_fds(int *fds, unsigned int nr_close_fds);
+int client_socket(int family, int type,
+		  const struct network_helper_opts *opts);
 int connect_to_addr(int type, const struct sockaddr_storage *addr, socklen_t len,
 		    const struct network_helper_opts *opts);
 int connect_to_fd(int server_fd, int timeout_ms);