[PATCH bpf-next v3 0/4] export send_recv_data

[PATCH bpf-next v3 0/4] export send_recv_data

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

v3:
 - add two more patches.
 - use log_err instead of ASSERT in v3.
 - let send_recv_data return int as Martin suggested.

v2:

Address Martin's comments for v1 (thanks.)
 - drop patch 1, "export send_byte helper".
 - drop "WRITE_ONCE(arg.stop, 0)".
 - rebased.

send_recv_data will be re-used in MPTCP bpf tests, but not included
in this set because it depends on other patches that have not been
in the bpf-next yet. It will be sent as another set soon.

Geliang Tang (4):
  selftests/bpf: Use log_err in network_helpers
  selftests/bpf: Add struct send_recv_arg
  selftests/bpf: Export send_recv_data helper
  selftests/bpf: Support nonblock for send_recv_data

 tools/testing/selftests/bpf/network_helpers.c | 125 +++++++++++++++++-
 tools/testing/selftests/bpf/network_helpers.h |   1 +
 .../selftests/bpf/prog_tests/bpf_tcp_ca.c     |  71 +---------
 3 files changed, 121 insertions(+), 76 deletions(-)

-- 
2.40.1

[PATCH bpf-next v3 1/4] selftests/bpf: Use log_err in network_helpers

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

The helpers ASSERT_OK/GE/OK_PTR should avoid using in public functions.
This patch uses log_err() to replace them in network_helpers.c.

And drop '#include "test_progs.h"' in it, include <pthread.h> and
<sys/param.h> instead.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/network_helpers.c | 22 ++++++++++++++-----
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 04175e16195a..dbcbe2ac51ba 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -7,11 +7,13 @@
 #include <string.h>
 #include <unistd.h>
 #include <sched.h>
+#include <pthread.h>
 
 #include <arpa/inet.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/un.h>
+#include <sys/param.h>
 
 #include <linux/err.h>
 #include <linux/in.h>
@@ -20,7 +22,6 @@
 
 #include "bpf_util.h"
 #include "network_helpers.h"
-#include "test_progs.h"
 
 #ifndef IPPROTO_MPTCP
 #define IPPROTO_MPTCP 262
@@ -442,22 +443,30 @@ struct nstoken *open_netns(const char *name)
 	struct nstoken *token;
 
 	token = calloc(1, sizeof(struct nstoken));
-	if (!ASSERT_OK_PTR(token, "malloc token"))
+	if (!token) {
+		log_err("malloc token");
 		return NULL;
+	}
 
 	token->orig_netns_fd = open("/proc/self/ns/net", O_RDONLY);
-	if (!ASSERT_GE(token->orig_netns_fd, 0, "open /proc/self/ns/net"))
+	if (token->orig_netns_fd <= 0) {
+		log_err("open /proc/self/ns/net");
 		goto fail;
+	}
 
 	snprintf(nspath, sizeof(nspath), "%s/%s", "/var/run/netns", name);
 	nsfd = open(nspath, O_RDONLY | O_CLOEXEC);
-	if (!ASSERT_GE(nsfd, 0, "open netns fd"))
+	if (nsfd <= 0) {
+		log_err("open netns fd");
 		goto fail;
+	}
 
 	err = setns(nsfd, CLONE_NEWNET);
 	close(nsfd);
-	if (!ASSERT_OK(err, "setns"))
+	if (err) {
+		log_err("setns");
 		goto fail;
+	}
 
 	return token;
 fail:
@@ -470,7 +479,8 @@ void close_netns(struct nstoken *token)
 	if (!token)
 		return;
 
-	ASSERT_OK(setns(token->orig_netns_fd, CLONE_NEWNET), "setns");
+	if (setns(token->orig_netns_fd, CLONE_NEWNET))
+		log_err("setns");
 	close(token->orig_netns_fd);
 	free(token);
 }
-- 
2.40.1

[PATCH bpf-next v3 2/4] selftests/bpf: Add struct send_recv_arg

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

Avoid setting total_bytes and stop as global variables, this patch adds
a new struct named send_recv_arg to pass arguments between threads. Put
these two variables together with fd into this struct and pass it to
server thread, so that server thread can access these two variables without
setting them as global ones.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 .../selftests/bpf/prog_tests/bpf_tcp_ca.c     | 34 ++++++++++++-------
 1 file changed, 22 insertions(+), 12 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 077b107130f6..64f172f02a9a 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
@@ -21,7 +21,6 @@
 
 static const unsigned int total_bytes = 10 * 1024 * 1024;
 static int expected_stg = 0xeB9F;
-static int stop;
 
 static int settcpca(int fd, const char *tcp_ca)
 {
@@ -34,13 +33,20 @@ static int settcpca(int fd, const char *tcp_ca)
 	return 0;
 }
 
+struct send_recv_arg {
+	int		fd;
+	uint32_t	bytes;
+	int		stop;
+};
+
 static void *server(void *arg)
 {
-	int lfd = (int)(long)arg, err = 0, fd;
+	struct send_recv_arg *a = (struct send_recv_arg *)arg;
 	ssize_t nr_sent = 0, bytes = 0;
 	char batch[1500];
+	int err = 0, fd;
 
-	fd = accept(lfd, NULL, NULL);
+	fd = accept(a->fd, NULL, NULL);
 	while (fd == -1) {
 		if (errno == EINTR)
 			continue;
@@ -53,9 +59,9 @@ static void *server(void *arg)
 		goto done;
 	}
 
-	while (bytes < total_bytes && !READ_ONCE(stop)) {
+	while (bytes < a->bytes && !READ_ONCE(a->stop)) {
 		nr_sent = send(fd, &batch,
-			       MIN(total_bytes - bytes, sizeof(batch)), 0);
+			       MIN(a->bytes - bytes, sizeof(batch)), 0);
 		if (nr_sent == -1 && errno == EINTR)
 			continue;
 		if (nr_sent == -1) {
@@ -65,13 +71,13 @@ static void *server(void *arg)
 		bytes += nr_sent;
 	}
 
-	ASSERT_EQ(bytes, total_bytes, "send");
+	ASSERT_EQ(bytes, a->bytes, "send");
 
 done:
 	if (fd >= 0)
 		close(fd);
 	if (err) {
-		WRITE_ONCE(stop, 1);
+		WRITE_ONCE(a->stop, 1);
 		return ERR_PTR(err);
 	}
 	return NULL;
@@ -80,18 +86,22 @@ static void *server(void *arg)
 static void do_test(const char *tcp_ca, const struct bpf_map *sk_stg_map)
 {
 	ssize_t nr_recv = 0, bytes = 0;
+	struct send_recv_arg arg = {
+		.bytes	= total_bytes,
+		.stop	= 0,
+	};
 	int lfd = -1, fd = -1;
 	pthread_t srv_thread;
 	void *thread_ret;
 	char batch[1500];
 	int err;
 
-	WRITE_ONCE(stop, 0);
-
 	lfd = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
 	if (!ASSERT_NEQ(lfd, -1, "socket"))
 		return;
 
+	arg.fd = lfd;
+
 	fd = socket(AF_INET6, SOCK_STREAM, 0);
 	if (!ASSERT_NEQ(fd, -1, "socket")) {
 		close(lfd);
@@ -123,12 +133,12 @@ static void do_test(const char *tcp_ca, const struct bpf_map *sk_stg_map)
 			goto done;
 	}
 
-	err = pthread_create(&srv_thread, NULL, server, (void *)(long)lfd);
+	err = pthread_create(&srv_thread, NULL, server, (void *)&arg);
 	if (!ASSERT_OK(err, "pthread_create"))
 		goto done;
 
 	/* recv total_bytes */
-	while (bytes < total_bytes && !READ_ONCE(stop)) {
+	while (bytes < total_bytes && !READ_ONCE(arg.stop)) {
 		nr_recv = recv(fd, &batch,
 			       MIN(total_bytes - bytes, sizeof(batch)), 0);
 		if (nr_recv == -1 && errno == EINTR)
@@ -140,7 +150,7 @@ static void do_test(const char *tcp_ca, const struct bpf_map *sk_stg_map)
 
 	ASSERT_EQ(bytes, total_bytes, "recv");
 
-	WRITE_ONCE(stop, 1);
+	WRITE_ONCE(arg.stop, 1);
 	pthread_join(srv_thread, &thread_ret);
 	ASSERT_OK(IS_ERR(thread_ret), "thread_ret");
 
-- 
2.40.1

[PATCH bpf-next v3 3/4] selftests/bpf: Export send_recv_data helper

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

This patch extracts the code to send and receive data into a new
helper named send_recv_data() in network_helpers.c and export it
in network_helpers.h.

This helper will be used for MPTCP BPF selftests.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/network_helpers.c | 96 +++++++++++++++++++
 tools/testing/selftests/bpf/network_helpers.h |  1 +
 .../selftests/bpf/prog_tests/bpf_tcp_ca.c     | 81 +---------------
 3 files changed, 98 insertions(+), 80 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index dbcbe2ac51ba..55d41508fe1f 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -555,3 +555,99 @@ int set_hw_ring_size(char *ifname, struct ethtool_ringparam *ring_param)
 	close(sockfd);
 	return 0;
 }
+
+struct send_recv_arg {
+	int		fd;
+	uint32_t	bytes;
+	int		stop;
+};
+
+static void *send_recv_server(void *arg)
+{
+	struct send_recv_arg *a = (struct send_recv_arg *)arg;
+	ssize_t nr_sent = 0, bytes = 0;
+	char batch[1500];
+	int err = 0, fd;
+
+	fd = accept(a->fd, NULL, NULL);
+	while (fd == -1) {
+		if (errno == EINTR)
+			continue;
+		err = -errno;
+		goto done;
+	}
+
+	if (settimeo(fd, 0)) {
+		err = -errno;
+		goto done;
+	}
+
+	while (bytes < a->bytes && !READ_ONCE(a->stop)) {
+		nr_sent = send(fd, &batch,
+			       MIN(a->bytes - bytes, sizeof(batch)), 0);
+		if (nr_sent == -1 && errno == EINTR)
+			continue;
+		if (nr_sent == -1) {
+			err = -errno;
+			break;
+		}
+		bytes += nr_sent;
+	}
+
+	if (bytes != a->bytes)
+		log_err("send");
+
+done:
+	if (fd >= 0)
+		close(fd);
+	if (err) {
+		WRITE_ONCE(a->stop, 1);
+		return ERR_PTR(err);
+	}
+	return NULL;
+}
+
+int send_recv_data(int lfd, int fd, uint32_t total_bytes)
+{
+	ssize_t nr_recv = 0, bytes = 0;
+	struct send_recv_arg arg = {
+		.fd	= lfd,
+		.bytes	= total_bytes,
+		.stop	= 0,
+	};
+	pthread_t srv_thread;
+	void *thread_ret;
+	char batch[1500];
+	int err;
+
+	err = pthread_create(&srv_thread, NULL, send_recv_server, (void *)&arg);
+	if (!err) {
+		log_err("pthread_create");
+		return err;
+	}
+
+	/* recv total_bytes */
+	while (bytes < total_bytes && !READ_ONCE(arg.stop)) {
+		nr_recv = recv(fd, &batch,
+			       MIN(total_bytes - bytes, sizeof(batch)), 0);
+		if (nr_recv == -1 && errno == EINTR)
+			continue;
+		if (nr_recv == -1)
+			break;
+		bytes += nr_recv;
+	}
+
+	if (bytes != total_bytes) {
+		log_err("recv");
+		return -1;
+	}
+
+	WRITE_ONCE(arg.stop, 1);
+	pthread_join(srv_thread, &thread_ret);
+	if (IS_ERR(thread_ret)) {
+		log_err("thread_ret");
+		return -1;
+	}
+
+	return 0;
+}
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index 6457445cc6e2..70f4e4c92733 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -76,6 +76,7 @@ struct nstoken;
  */
 struct nstoken *open_netns(const char *name);
 void close_netns(struct nstoken *token);
+int send_recv_data(int lfd, int fd, uint32_t total_bytes);
 
 static __u16 csum_fold(__u32 csum)
 {
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 64f172f02a9a..907bac46c774 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
@@ -33,75 +33,15 @@ static int settcpca(int fd, const char *tcp_ca)
 	return 0;
 }
 
-struct send_recv_arg {
-	int		fd;
-	uint32_t	bytes;
-	int		stop;
-};
-
-static void *server(void *arg)
-{
-	struct send_recv_arg *a = (struct send_recv_arg *)arg;
-	ssize_t nr_sent = 0, bytes = 0;
-	char batch[1500];
-	int err = 0, fd;
-
-	fd = accept(a->fd, NULL, NULL);
-	while (fd == -1) {
-		if (errno == EINTR)
-			continue;
-		err = -errno;
-		goto done;
-	}
-
-	if (settimeo(fd, 0)) {
-		err = -errno;
-		goto done;
-	}
-
-	while (bytes < a->bytes && !READ_ONCE(a->stop)) {
-		nr_sent = send(fd, &batch,
-			       MIN(a->bytes - bytes, sizeof(batch)), 0);
-		if (nr_sent == -1 && errno == EINTR)
-			continue;
-		if (nr_sent == -1) {
-			err = -errno;
-			break;
-		}
-		bytes += nr_sent;
-	}
-
-	ASSERT_EQ(bytes, a->bytes, "send");
-
-done:
-	if (fd >= 0)
-		close(fd);
-	if (err) {
-		WRITE_ONCE(a->stop, 1);
-		return ERR_PTR(err);
-	}
-	return NULL;
-}
-
 static void do_test(const char *tcp_ca, const struct bpf_map *sk_stg_map)
 {
-	ssize_t nr_recv = 0, bytes = 0;
-	struct send_recv_arg arg = {
-		.bytes	= total_bytes,
-		.stop	= 0,
-	};
 	int lfd = -1, fd = -1;
-	pthread_t srv_thread;
-	void *thread_ret;
-	char batch[1500];
 	int err;
 
 	lfd = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
 	if (!ASSERT_NEQ(lfd, -1, "socket"))
 		return;
 
-	arg.fd = lfd;
-
 	fd = socket(AF_INET6, SOCK_STREAM, 0);
 	if (!ASSERT_NEQ(fd, -1, "socket")) {
 		close(lfd);
@@ -133,26 +73,7 @@ static void do_test(const char *tcp_ca, const struct bpf_map *sk_stg_map)
 			goto done;
 	}
 
-	err = pthread_create(&srv_thread, NULL, server, (void *)&arg);
-	if (!ASSERT_OK(err, "pthread_create"))
-		goto done;
-
-	/* recv total_bytes */
-	while (bytes < total_bytes && !READ_ONCE(arg.stop)) {
-		nr_recv = recv(fd, &batch,
-			       MIN(total_bytes - bytes, sizeof(batch)), 0);
-		if (nr_recv == -1 && errno == EINTR)
-			continue;
-		if (nr_recv == -1)
-			break;
-		bytes += nr_recv;
-	}
-
-	ASSERT_EQ(bytes, total_bytes, "recv");
-
-	WRITE_ONCE(arg.stop, 1);
-	pthread_join(srv_thread, &thread_ret);
-	ASSERT_OK(IS_ERR(thread_ret), "thread_ret");
+	ASSERT_OK(send_recv_data(lfd, fd, total_bytes), "send_recv_data");
 
 done:
 	close(lfd);
-- 
2.40.1

[PATCH bpf-next v3 4/4] selftests/bpf: Support nonblock for send_recv_data

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

Some tests, such as the MPTCP bpf tests, require send_recv_data helper
to run in nonblock mode.

This patch adds nonblock support for send_recv_data(). Check if it is
currently in nonblock mode, and if so, ignore EWOULDBLOCK to continue
sending and receiving.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/network_helpers.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 55d41508fe1f..08a204828ded 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -565,6 +565,7 @@ struct send_recv_arg {
 static void *send_recv_server(void *arg)
 {
 	struct send_recv_arg *a = (struct send_recv_arg *)arg;
+	int flags = fcntl(a->fd, F_GETFL);
 	ssize_t nr_sent = 0, bytes = 0;
 	char batch[1500];
 	int err = 0, fd;
@@ -588,6 +589,8 @@ static void *send_recv_server(void *arg)
 		if (nr_sent == -1 && errno == EINTR)
 			continue;
 		if (nr_sent == -1) {
+			if (flags & O_NONBLOCK && errno == EWOULDBLOCK)
+				continue;
 			err = -errno;
 			break;
 		}
@@ -609,6 +612,7 @@ static void *send_recv_server(void *arg)
 
 int send_recv_data(int lfd, int fd, uint32_t total_bytes)
 {
+	int flags = fcntl(lfd, F_GETFL);
 	ssize_t nr_recv = 0, bytes = 0;
 	struct send_recv_arg arg = {
 		.fd	= lfd,
@@ -632,8 +636,11 @@ int send_recv_data(int lfd, int fd, uint32_t total_bytes)
 			       MIN(total_bytes - bytes, sizeof(batch)), 0);
 		if (nr_recv == -1 && errno == EINTR)
 			continue;
-		if (nr_recv == -1)
+		if (nr_recv == -1) {
+			if (flags & O_NONBLOCK && errno == EWOULDBLOCK)
+				continue;
 			break;
+		}
 		bytes += nr_recv;
 	}
 
-- 
2.40.1

Re: [PATCH bpf-next v3 3/4] selftests/bpf: Export send_recv_data helper

[Geliang Tang]

On Tue, 2024-04-09 at 18:57 +0800, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> This patch extracts the code to send and receive data into a new
> helper named send_recv_data() in network_helpers.c and export it
> in network_helpers.h.
> 
> This helper will be used for MPTCP BPF selftests.
> 
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>  tools/testing/selftests/bpf/network_helpers.c | 96
> +++++++++++++++++++
>  tools/testing/selftests/bpf/network_helpers.h |  1 +
>  .../selftests/bpf/prog_tests/bpf_tcp_ca.c     | 81 +---------------
>  3 files changed, 98 insertions(+), 80 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/network_helpers.c
> b/tools/testing/selftests/bpf/network_helpers.c
> index dbcbe2ac51ba..55d41508fe1f 100644
> --- a/tools/testing/selftests/bpf/network_helpers.c
> +++ b/tools/testing/selftests/bpf/network_helpers.c
> @@ -555,3 +555,99 @@ int set_hw_ring_size(char *ifname, struct
> ethtool_ringparam *ring_param)
>  	close(sockfd);
>  	return 0;
>  }
> +
> +struct send_recv_arg {
> +	int		fd;
> +	uint32_t	bytes;
> +	int		stop;
> +};
> +
> +static void *send_recv_server(void *arg)
> +{
> +	struct send_recv_arg *a = (struct send_recv_arg *)arg;
> +	ssize_t nr_sent = 0, bytes = 0;
> +	char batch[1500];
> +	int err = 0, fd;
> +
> +	fd = accept(a->fd, NULL, NULL);
> +	while (fd == -1) {
> +		if (errno == EINTR)
> +			continue;
> +		err = -errno;
> +		goto done;
> +	}
> +
> +	if (settimeo(fd, 0)) {
> +		err = -errno;
> +		goto done;
> +	}
> +
> +	while (bytes < a->bytes && !READ_ONCE(a->stop)) {
> +		nr_sent = send(fd, &batch,
> +			       MIN(a->bytes - bytes, sizeof(batch)),
> 0);
> +		if (nr_sent == -1 && errno == EINTR)
> +			continue;
> +		if (nr_sent == -1) {
> +			err = -errno;
> +			break;
> +		}
> +		bytes += nr_sent;
> +	}
> +
> +	if (bytes != a->bytes)
> +		log_err("send");
> +
> +done:
> +	if (fd >= 0)
> +		close(fd);
> +	if (err) {
> +		WRITE_ONCE(a->stop, 1);
> +		return ERR_PTR(err);
> +	}
> +	return NULL;
> +}
> +
> +int send_recv_data(int lfd, int fd, uint32_t total_bytes)
> +{
> +	ssize_t nr_recv = 0, bytes = 0;
> +	struct send_recv_arg arg = {
> +		.fd	= lfd,
> +		.bytes	= total_bytes,
> +		.stop	= 0,
> +	};
> +	pthread_t srv_thread;
> +	void *thread_ret;
> +	char batch[1500];
> +	int err;
> +
> +	err = pthread_create(&srv_thread, NULL, send_recv_server,
> (void *)&arg);
> +	if (!err) {

Sorry, here should be 'if (err)'.

Changes Requested.

-Geliang

> +		log_err("pthread_create");
> +		return err;
> +	}
> +
> +	/* recv total_bytes */
> +	while (bytes < total_bytes && !READ_ONCE(arg.stop)) {
> +		nr_recv = recv(fd, &batch,
> +			       MIN(total_bytes - bytes,
> sizeof(batch)), 0);
> +		if (nr_recv == -1 && errno == EINTR)
> +			continue;
> +		if (nr_recv == -1)
> +			break;
> +		bytes += nr_recv;
> +	}
> +
> +	if (bytes != total_bytes) {
> +		log_err("recv");
> +		return -1;
> +	}
> +
> +	WRITE_ONCE(arg.stop, 1);
> +	pthread_join(srv_thread, &thread_ret);
> +	if (IS_ERR(thread_ret)) {
> +		log_err("thread_ret");
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> diff --git a/tools/testing/selftests/bpf/network_helpers.h
> b/tools/testing/selftests/bpf/network_helpers.h
> index 6457445cc6e2..70f4e4c92733 100644
> --- a/tools/testing/selftests/bpf/network_helpers.h
> +++ b/tools/testing/selftests/bpf/network_helpers.h
> @@ -76,6 +76,7 @@ struct nstoken;
>   */
>  struct nstoken *open_netns(const char *name);
>  void close_netns(struct nstoken *token);
> +int send_recv_data(int lfd, int fd, uint32_t total_bytes);
>  
>  static __u16 csum_fold(__u32 csum)
>  {
> 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 64f172f02a9a..907bac46c774 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
> @@ -33,75 +33,15 @@ static int settcpca(int fd, const char *tcp_ca)
>  	return 0;
>  }
>  
> -struct send_recv_arg {
> -	int		fd;
> -	uint32_t	bytes;
> -	int		stop;
> -};
> -
> -static void *server(void *arg)
> -{
> -	struct send_recv_arg *a = (struct send_recv_arg *)arg;
> -	ssize_t nr_sent = 0, bytes = 0;
> -	char batch[1500];
> -	int err = 0, fd;
> -
> -	fd = accept(a->fd, NULL, NULL);
> -	while (fd == -1) {
> -		if (errno == EINTR)
> -			continue;
> -		err = -errno;
> -		goto done;
> -	}
> -
> -	if (settimeo(fd, 0)) {
> -		err = -errno;
> -		goto done;
> -	}
> -
> -	while (bytes < a->bytes && !READ_ONCE(a->stop)) {
> -		nr_sent = send(fd, &batch,
> -			       MIN(a->bytes - bytes, sizeof(batch)),
> 0);
> -		if (nr_sent == -1 && errno == EINTR)
> -			continue;
> -		if (nr_sent == -1) {
> -			err = -errno;
> -			break;
> -		}
> -		bytes += nr_sent;
> -	}
> -
> -	ASSERT_EQ(bytes, a->bytes, "send");
> -
> -done:
> -	if (fd >= 0)
> -		close(fd);
> -	if (err) {
> -		WRITE_ONCE(a->stop, 1);
> -		return ERR_PTR(err);
> -	}
> -	return NULL;
> -}
> -
>  static void do_test(const char *tcp_ca, const struct bpf_map
> *sk_stg_map)
>  {
> -	ssize_t nr_recv = 0, bytes = 0;
> -	struct send_recv_arg arg = {
> -		.bytes	= total_bytes,
> -		.stop	= 0,
> -	};
>  	int lfd = -1, fd = -1;
> -	pthread_t srv_thread;
> -	void *thread_ret;
> -	char batch[1500];
>  	int err;
>  
>  	lfd = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
>  	if (!ASSERT_NEQ(lfd, -1, "socket"))
>  		return;
>  
> -	arg.fd = lfd;
> -
>  	fd = socket(AF_INET6, SOCK_STREAM, 0);
>  	if (!ASSERT_NEQ(fd, -1, "socket")) {
>  		close(lfd);
> @@ -133,26 +73,7 @@ static void do_test(const char *tcp_ca, const
> struct bpf_map *sk_stg_map)
>  			goto done;
>  	}
>  
> -	err = pthread_create(&srv_thread, NULL, server, (void
> *)&arg);
> -	if (!ASSERT_OK(err, "pthread_create"))
> -		goto done;
> -
> -	/* recv total_bytes */
> -	while (bytes < total_bytes && !READ_ONCE(arg.stop)) {
> -		nr_recv = recv(fd, &batch,
> -			       MIN(total_bytes - bytes,
> sizeof(batch)), 0);
> -		if (nr_recv == -1 && errno == EINTR)
> -			continue;
> -		if (nr_recv == -1)
> -			break;
> -		bytes += nr_recv;
> -	}
> -
> -	ASSERT_EQ(bytes, total_bytes, "recv");
> -
> -	WRITE_ONCE(arg.stop, 1);
> -	pthread_join(srv_thread, &thread_ret);
> -	ASSERT_OK(IS_ERR(thread_ret), "thread_ret");
> +	ASSERT_OK(send_recv_data(lfd, fd, total_bytes),
> "send_recv_data");
>  
>  done:
>  	close(lfd);