selftests/bpf: Add expect_errno for network_helper_opts

The errno EPERM is skipped in connect_fd_to_addr() by cgroup_v1v2 tests.
More generally, it makes sense to add a struct member "expect_errno" for
network_helper_opts to identify the expect errno to be skipped.

Correspondingly, connect_fd_to_addr() helper needs to add a new parameter
"expect_errno" too to accept "opts->expect_errno" passed from the caller
connect_to_addr() or connect_fd_to_fd().

With this change, only need to set "expect_errno" as EPERM in run_test()
in prog_tests/cgroup_v1v2.c.

Signed-off-by: Geliang Tang <[email protected]>

Author: Geliang Tang

tools/testing/selftests/bpf/network_helpers.c

@@ -279,7 +279,8 @@ int client_socket(int family, int type,
 
 static int connect_fd_to_addr(int fd,
 			      const struct sockaddr_storage *addr,
-			      socklen_t addrlen, const bool must_fail)
+			      socklen_t addrlen, const bool must_fail,
+			      const int expect_errno)
 {
 	int ret;
 
@@ -290,7 +291,7 @@ static int connect_fd_to_addr(int fd,
 			log_err("Unexpected success to connect to server");
 			return -1;
 		}
-		if (errno != EPERM) {
+		if (errno != expect_errno) {
 			log_err("Unexpected error from connect to server");
 			return -1;
 		}
@@ -318,7 +319,8 @@ int connect_to_addr(int type, const struct sockaddr_storage *addr, socklen_t add
 		return -1;
 	}
 
-	if (connect_fd_to_addr(fd, addr, addrlen, opts->must_fail))
+	if (connect_fd_to_addr(fd, addr, addrlen, opts->must_fail,
+			       opts->expect_errno))
 		goto error_close;
 
 	return fd;
@@ -386,7 +388,8 @@ int connect_fd_to_fd(int client_fd, int server_fd,
 		return -1;
 	}
 
-	if (connect_fd_to_addr(client_fd, &addr, len, opts->must_fail))
+	if (connect_fd_to_addr(client_fd, &addr, len, opts->must_fail,
+			       opts->expect_errno))
 		return -1;
 
 	return 0;

tools/testing/selftests/bpf/network_helpers.h

@@ -24,6 +24,7 @@ typedef __u16 __sum16;
 struct network_helper_opts {
 	int timeout_ms;
 	bool must_fail;
+	int expect_errno;
 	int proto;
 	/* The backlog argument for listen(), defines the maximum length to which
 	 * the queue of pending connections for sockfd may grow.

tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c

@@ -11,6 +11,7 @@ static int run_test(int cgroup_fd, int server_fd, bool classid)
 {
 	struct network_helper_opts opts = {
 		.must_fail = true,
+		.expect_errno = EPERM,
 	};
 	struct connect4_dropper *skel;
 	int fd, err = 0;