[PATCH bpf-next 0/5] use network helpers, part 9

[PATCH bpf-next 0/5] use network helpers, part 9

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

This is the 9th part of series "use network helpers" all BPF selftests
wide.

Patches 1-2 update network helpers interfaces suggested by Martin.
Patch 3 adds a new helper connect_to_addr_str() as Martin suggested
instead of adding connect_fd_to_addr_str().
Patch 4 uses this newly added helper in make_client().
Patch 5 uses make_client() in sk_lookup and drop make_socket().

Geliang Tang (5):
  selftests/bpf: Drop type of connect_to_fd_opts
  selftests/bpf: Drop must_fail from network_helper_opts
  selftests/bpf: Add connect_to_addr_str helper
  selftests/bpf: Use connect_to_addr_str in sk_lookup
  selftests/bpf: Drop make_socket in sk_lookup

 tools/testing/selftests/bpf/network_helpers.c | 67 +++++++--------
 tools/testing/selftests/bpf/network_helpers.h |  5 +-
 .../selftests/bpf/prog_tests/bpf_tcp_ca.c     |  2 +-
 .../selftests/bpf/prog_tests/cgroup_v1v2.c    | 10 +--
 .../selftests/bpf/prog_tests/sk_lookup.c      | 84 ++++---------------
 5 files changed, 53 insertions(+), 115 deletions(-)

-- 
2.43.0

[PATCH bpf-next 1/5] selftests/bpf: Drop type of connect_to_fd_opts

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

The "type" parameter of connect_to_fd_opts() is redundant of "server_fd".
Since the "type" can be obtained inside by invoking getsockopt(SO_TYPE),
without passing it in as a parameter.

This patch drops the "type" parameter of connect_to_fd_opts() and updates
its callers.

Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/network_helpers.c | 21 ++++++++++---------
 tools/testing/selftests/bpf/network_helpers.h |  2 +-
 .../selftests/bpf/prog_tests/bpf_tcp_ca.c     |  2 +-
 .../selftests/bpf/prog_tests/cgroup_v1v2.c    |  4 ++--
 4 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index e0cba4178e41..15e0e0bb7553 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -328,14 +328,21 @@ int connect_to_addr(int type, const struct sockaddr_storage *addr, socklen_t add
 	return -1;
 }
 
-int connect_to_fd_opts(int server_fd, int type, const struct network_helper_opts *opts)
+int connect_to_fd_opts(int server_fd, const struct network_helper_opts *opts)
 {
 	struct sockaddr_storage addr;
-	socklen_t addrlen;
+	socklen_t addrlen, optlen;
+	int type;
 
 	if (!opts)
 		opts = &default_opts;
 
+	optlen = sizeof(type);
+	if (getsockopt(server_fd, SOL_SOCKET, SO_TYPE, &type, &optlen)) {
+		log_err("getsockopt(SOL_TYPE)");
+		return -1;
+	}
+
 	addrlen = sizeof(addr);
 	if (getsockname(server_fd, (struct sockaddr *)&addr, &addrlen)) {
 		log_err("Failed to get server addr");
@@ -350,14 +357,8 @@ int connect_to_fd(int server_fd, int timeout_ms)
 	struct network_helper_opts opts = {
 		.timeout_ms = timeout_ms,
 	};
-	int type, protocol;
 	socklen_t optlen;
-
-	optlen = sizeof(type);
-	if (getsockopt(server_fd, SOL_SOCKET, SO_TYPE, &type, &optlen)) {
-		log_err("getsockopt(SOL_TYPE)");
-		return -1;
-	}
+	int protocol;
 
 	optlen = sizeof(protocol);
 	if (getsockopt(server_fd, SOL_SOCKET, SO_PROTOCOL, &protocol, &optlen)) {
@@ -366,7 +367,7 @@ int connect_to_fd(int server_fd, int timeout_ms)
 	}
 	opts.proto = protocol;
 
-	return connect_to_fd_opts(server_fd, type, &opts);
+	return connect_to_fd_opts(server_fd, &opts);
 }
 
 int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms)
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index aac5b94d6379..5b548c0c60de 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -71,7 +71,7 @@ int client_socket(int family, int type,
 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);
-int connect_to_fd_opts(int server_fd, int type, const struct network_helper_opts *opts);
+int connect_to_fd_opts(int server_fd, const struct network_helper_opts *opts);
 int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms);
 int fastopen_connect(int server_fd, const char *data, unsigned int data_len,
 		     int timeout_ms);
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 63422f4f3896..1d494b4453f4 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
@@ -49,7 +49,7 @@ static bool start_test(char *addr_str,
 		goto err;
 
 	/* connect to server */
-	*cli_fd = connect_to_fd_opts(*srv_fd, SOCK_STREAM, cli_opts);
+	*cli_fd = connect_to_fd_opts(*srv_fd, cli_opts);
 	if (!ASSERT_NEQ(*cli_fd, -1, "connect_to_fd_opts"))
 		goto err;
 
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
index 9709c8db7275..addf720428f7 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
@@ -32,7 +32,7 @@ static int run_test(int cgroup_fd, int server_fd, bool classid)
 		goto out;
 	}
 
-	fd = connect_to_fd_opts(server_fd, SOCK_STREAM, &opts);
+	fd = connect_to_fd_opts(server_fd, &opts);
 	if (fd < 0)
 		err = -1;
 	else
@@ -52,7 +52,7 @@ void test_cgroup_v1v2(void)
 	server_fd = start_server(AF_INET, SOCK_STREAM, NULL, port, 0);
 	if (!ASSERT_GE(server_fd, 0, "server_fd"))
 		return;
-	client_fd = connect_to_fd_opts(server_fd, SOCK_STREAM, &opts);
+	client_fd = connect_to_fd_opts(server_fd, &opts);
 	if (!ASSERT_GE(client_fd, 0, "client_fd")) {
 		close(server_fd);
 		return;
-- 
2.43.0

[PATCH bpf-next 2/5] selftests/bpf: Drop must_fail from network_helper_opts

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

The struct member "must_fail" of network_helper_opts() is only used in
cgroup_v1v2 tests, it makes sense to drop it from network_helper_opts.

Return value (fd) of connect_to_fd_opts() and the expect errno (EPERM)
can be checked in cgroup_v1v2.c directly, no need to check them in
connect_fd_to_addr() in network_helpers.c.

This also makes connect_fd_to_addr() function useless. It can be replaced
by connect().

Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/network_helpers.c | 31 ++-----------------
 tools/testing/selftests/bpf/network_helpers.h |  1 -
 .../selftests/bpf/prog_tests/cgroup_v1v2.c    |  6 ++--
 3 files changed, 4 insertions(+), 34 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 15e0e0bb7553..48c27c810db7 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -277,33 +277,6 @@ int client_socket(int family, int type,
 	return -1;
 }
 
-static int connect_fd_to_addr(int fd,
-			      const struct sockaddr_storage *addr,
-			      socklen_t addrlen, const bool must_fail)
-{
-	int ret;
-
-	errno = 0;
-	ret = connect(fd, (const struct sockaddr *)addr, addrlen);
-	if (must_fail) {
-		if (!ret) {
-			log_err("Unexpected success to connect to server");
-			return -1;
-		}
-		if (errno != EPERM) {
-			log_err("Unexpected error from connect to server");
-			return -1;
-		}
-	} else {
-		if (ret) {
-			log_err("Failed to connect to server");
-			return -1;
-		}
-	}
-
-	return 0;
-}
-
 int connect_to_addr(int type, const struct sockaddr_storage *addr, socklen_t addrlen,
 		    const struct network_helper_opts *opts)
 {
@@ -318,7 +291,7 @@ 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, (const struct sockaddr *)addr, addrlen))
 		goto error_close;
 
 	return fd;
@@ -383,7 +356,7 @@ int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms)
 		return -1;
 	}
 
-	if (connect_fd_to_addr(client_fd, &addr, len, false))
+	if (connect(client_fd, (const struct sockaddr *)&addr, len))
 		return -1;
 
 	return 0;
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index 5b548c0c60de..f39eeb5a4594 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -23,7 +23,6 @@ typedef __u16 __sum16;
 
 struct network_helper_opts {
 	int timeout_ms;
-	bool must_fail;
 	int proto;
 	/* +ve: Passed to listen() as-is.
 	 *   0: Default when the test does not set
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
index addf720428f7..eda67b629c67 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
@@ -9,9 +9,7 @@
 
 static int run_test(int cgroup_fd, int server_fd, bool classid)
 {
-	struct network_helper_opts opts = {
-		.must_fail = true,
-	};
+	struct network_helper_opts opts = {};
 	struct connect4_dropper *skel;
 	int fd, err = 0;
 
@@ -33,7 +31,7 @@ static int run_test(int cgroup_fd, int server_fd, bool classid)
 	}
 
 	fd = connect_to_fd_opts(server_fd, &opts);
-	if (fd < 0)
+	if (fd < 0 && errno != EPERM)
 		err = -1;
 	else
 		close(fd);
-- 
2.43.0

[PATCH bpf-next 3/5] selftests/bpf: Add connect_to_addr_str helper

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

Similar to connect_to_addr() helper for connecting to a server with the
given sockaddr_storage type address, this patch adds a new helper named
connect_to_addr_str() for connecting to a server with the given string
type address "addr_str", together with its "family" and "port" as other
parameters of connect_to_addr_str().

In connect_to_addr_str(), the parameters "family", "addr_str" and "port"
are used to create a sockaddr_storage type address "addr" by invoking
make_sockaddr(). Then pass this "addr" together with "addrlen", "type"
and "opts" to connect_to_addr().

Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/network_helpers.c | 17 +++++++++++++++++
 tools/testing/selftests/bpf/network_helpers.h |  2 ++
 2 files changed, 19 insertions(+)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 48c27c810db7..139fac70de00 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -301,6 +301,23 @@ int connect_to_addr(int type, const struct sockaddr_storage *addr, socklen_t add
 	return -1;
 }
 
+int connect_to_addr_str(int family, int type, const char *addr_str, __u16 port,
+			const struct network_helper_opts *opts)
+{
+	struct sockaddr_storage addr;
+	socklen_t addrlen;
+	int err;
+
+	if (!opts)
+		opts = &default_opts;
+
+	err = make_sockaddr(family, addr_str, port, &addr, &addrlen);
+	if (err)
+		return -1;
+
+	return connect_to_addr(type, &addr, addrlen, opts);
+}
+
 int connect_to_fd_opts(int server_fd, const struct network_helper_opts *opts)
 {
 	struct sockaddr_storage addr;
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index f39eeb5a4594..cce56955371f 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -69,6 +69,8 @@ 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_addr_str(int family, int type, const char *addr_str, __u16 port,
+			const struct network_helper_opts *opts);
 int connect_to_fd(int server_fd, int timeout_ms);
 int connect_to_fd_opts(int server_fd, const struct network_helper_opts *opts);
 int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms);
-- 
2.43.0

[PATCH bpf-next 4/5] selftests/bpf: Use connect_to_addr_str in sk_lookup

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

This patch uses the new helper connect_to_addr_str() in make_client()
instead of using local defined function make_socket() + connect(). This
local function can be dropped latter.

A new parameter "expect_errno" is added for make_client() too to allow
different "expect_errno" is passed to make_client(). It is used to check
with "errno" after invoking connect_to_addr_str().

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 .../selftests/bpf/prog_tests/sk_lookup.c      | 26 +++++++------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
index ae87c00867ba..beea7866b37f 100644
--- a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
+++ b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
@@ -229,25 +229,19 @@ static int make_server(int sotype, const char *ip, int port,
 	return -1;
 }
 
-static int make_client(int sotype, const char *ip, int port)
+static int make_client(int sotype, const char *ip, int port, int expect_errno)
 {
-	struct sockaddr_storage addr = {0};
-	int err, fd;
-
-	fd = make_socket(sotype, ip, port, &addr);
-	if (fd < 0)
-		return -1;
+	int fd;
 
-	err = connect(fd, (void *)&addr, inetaddr_len(&addr));
-	if (CHECK(err, "make_client", "connect")) {
+	fd = connect_to_addr_str(is_ipv6(ip) ? AF_INET6 : AF_INET,
+				 sotype, ip, port, NULL);
+	if (CHECK(fd < 0 && (!expect_errno || errno != expect_errno),
+		  "make_client", "connect_to_addr_str")) {
 		log_err("failed to connect client socket");
-		goto fail;
+		return -1;
 	}
 
 	return fd;
-fail:
-	close(fd);
-	return -1;
 }
 
 static __u64 socket_cookie(int fd)
@@ -646,7 +640,7 @@ static void run_lookup_prog(const struct test *t)
 			goto close;
 	}
 
-	client_fd = make_client(t->sotype, t->connect_to.ip, t->connect_to.port);
+	client_fd = make_client(t->sotype, t->connect_to.ip, t->connect_to.port, 0);
 	if (client_fd < 0)
 		goto close;
 
@@ -1152,7 +1146,7 @@ static void run_sk_assign_connected(struct test_sk_lookup *skel,
 	if (server_fd < 0)
 		return;
 
-	connected_fd = make_client(sotype, EXT_IP4, EXT_PORT);
+	connected_fd = make_client(sotype, EXT_IP4, EXT_PORT, 0);
 	if (connected_fd < 0)
 		goto out_close_server;
 
@@ -1166,7 +1160,7 @@ static void run_sk_assign_connected(struct test_sk_lookup *skel,
 		goto out_close_connected;
 
 	/* Try to redirect TCP SYN / UDP packet to a connected socket */
-	client_fd = make_client(sotype, EXT_IP4, EXT_PORT);
+	client_fd = make_client(sotype, EXT_IP4, EXT_PORT, 0);
 	if (client_fd < 0)
 		goto out_unlink_prog;
 	if (sotype == SOCK_DGRAM) {
-- 
2.43.0

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

[Geliang Tang]

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",
 		  "unexpected error %d\n", errno))
 		goto out_close_client;
-- 
2.43.0

Re: [PATCH bpf-next 2/5] selftests/bpf: Drop must_fail from network_helper_opts

[Martin KaFai Lau]

On 7/10/24 7:52 PM, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> The struct member "must_fail" of network_helper_opts() is only used in
> cgroup_v1v2 tests, it makes sense to drop it from network_helper_opts.
> 
> Return value (fd) of connect_to_fd_opts() and the expect errno (EPERM)
> can be checked in cgroup_v1v2.c directly, no need to check them in
> connect_fd_to_addr() in network_helpers.c.
> 
> This also makes connect_fd_to_addr() function useless. It can be replaced
> by connect().
> 
> Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>   tools/testing/selftests/bpf/network_helpers.c | 31 ++-----------------
>   tools/testing/selftests/bpf/network_helpers.h |  1 -
>   .../selftests/bpf/prog_tests/cgroup_v1v2.c    |  6 ++--
>   3 files changed, 4 insertions(+), 34 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
> index 15e0e0bb7553..48c27c810db7 100644
> --- a/tools/testing/selftests/bpf/network_helpers.c
> +++ b/tools/testing/selftests/bpf/network_helpers.c
> @@ -277,33 +277,6 @@ int client_socket(int family, int type,
>   	return -1;
>   }
>   
> -static int connect_fd_to_addr(int fd,
> -			      const struct sockaddr_storage *addr,
> -			      socklen_t addrlen, const bool must_fail)
> -{
> -	int ret;
> -
> -	errno = 0;
> -	ret = connect(fd, (const struct sockaddr *)addr, addrlen);
> -	if (must_fail) {
> -		if (!ret) {
> -			log_err("Unexpected success to connect to server");
> -			return -1;
> -		}
> -		if (errno != EPERM) {
> -			log_err("Unexpected error from connect to server");
> -			return -1;
> -		}
> -	} else {
> -		if (ret) {
> -			log_err("Failed to connect to server");
> -			return -1;
> -		}
> -	}
> -
> -	return 0;
> -}
> -
>   int connect_to_addr(int type, const struct sockaddr_storage *addr, socklen_t addrlen,
>   		    const struct network_helper_opts *opts)
>   {
> @@ -318,7 +291,7 @@ 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, (const struct sockaddr *)addr, addrlen))
>   		goto error_close;
>   
>   	return fd;
> @@ -383,7 +356,7 @@ int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms)
>   		return -1;
>   	}
>   
> -	if (connect_fd_to_addr(client_fd, &addr, len, false))
> +	if (connect(client_fd, (const struct sockaddr *)&addr, len))
>   		return -1;
>   
>   	return 0;
> diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
> index 5b548c0c60de..f39eeb5a4594 100644
> --- a/tools/testing/selftests/bpf/network_helpers.h
> +++ b/tools/testing/selftests/bpf/network_helpers.h
> @@ -23,7 +23,6 @@ typedef __u16 __sum16;
>   
>   struct network_helper_opts {
>   	int timeout_ms;
> -	bool must_fail;
>   	int proto;
>   	/* +ve: Passed to listen() as-is.
>   	 *   0: Default when the test does not set
> diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
> index addf720428f7..eda67b629c67 100644
> --- a/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
> +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_v1v2.c
> @@ -9,9 +9,7 @@
>   
>   static int run_test(int cgroup_fd, int server_fd, bool classid)
>   {
> -	struct network_helper_opts opts = {
> -		.must_fail = true,
> -	};
> +	struct network_helper_opts opts = {};
>   	struct connect4_dropper *skel;
>   	int fd, err = 0;
>   
> @@ -33,7 +31,7 @@ static int run_test(int cgroup_fd, int server_fd, bool classid)
>   	}
>   
>   	fd = connect_to_fd_opts(server_fd, &opts);
> -	if (fd < 0)
> +	if (fd < 0 && errno != EPERM)


The if test is incorrect.

>   		err = -1;
>   	else
>   		close(fd);

Beside close(-1) which is not good, it does not treat an OK_FD as an error and 
that is the whole test trying to catch.

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