1 files changed, 151 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/fin_ack_lat.c b/tools/testing/selftests/net/fin_ack_lat.c
new file mode 100644
index 000000000000..70187494b57a
--- /dev/null
+++ b/tools/testing/selftests/net/fin_ack_lat.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+static int child_pid;
+
+static unsigned long timediff(struct timeval s, struct timeval e)
+{
+	unsigned long s_us, e_us;
+
+	s_us = s.tv_sec * 1000000 + s.tv_usec;
+	e_us = e.tv_sec * 1000000 + e.tv_usec;
+	if (s_us > e_us)
+		return 0;
+	return e_us - s_us;
+}
+
+static void client(int port)
+{
+	int sock = 0;
+	struct sockaddr_in addr, laddr;
+	socklen_t len = sizeof(laddr);
+	struct linger sl;
+	int flag = 1;
+	int buffer;
+	struct timeval start, end;
+	unsigned long lat, sum_lat = 0, nr_lat = 0;
+
+	while (1) {
+		gettimeofday(&start, NULL);
+
+		sock = socket(AF_INET, SOCK_STREAM, 0);
+		if (sock < 0)
+			error(-1, errno, "socket creation");
+
+		sl.l_onoff = 1;
+		sl.l_linger = 0;
+		if (setsockopt(sock, SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)))
+			error(-1, errno, "setsockopt(linger)");
+
+		if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY,
+					&flag, sizeof(flag)))
+			error(-1, errno, "setsockopt(nodelay)");
+
+		addr.sin_family = AF_INET;
+		addr.sin_port = htons(port);
+
+		if (inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr) <= 0)
+			error(-1, errno, "inet_pton");
+
+		if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
+			error(-1, errno, "connect");
+
+		send(sock, &buffer, sizeof(buffer), 0);
+		if (read(sock, &buffer, sizeof(buffer)) == -1)
+			error(-1, errno, "waiting read");
+
+		gettimeofday(&end, NULL);
+		lat = timediff(start, end);
+		sum_lat += lat;
+		nr_lat++;
+		if (lat < 100000)
+			goto close;
+
+		if (getsockname(sock, (struct sockaddr *)&laddr, &len) == -1)
+			error(-1, errno, "getsockname");
+		printf("port: %d, lat: %lu, avg: %lu, nr: %lu\n",
+				ntohs(laddr.sin_port), lat,
+				sum_lat / nr_lat, nr_lat);
+close:
+		fflush(stdout);
+		close(sock);
+	}
+}
+
+static void server(int sock, struct sockaddr_in address)
+{
+	int accepted;
+	int addrlen = sizeof(address);
+	int buffer;
+
+	while (1) {
+		accepted = accept(sock, (struct sockaddr *)&address,
+				(socklen_t *)&addrlen);
+		if (accepted < 0)
+			error(-1, errno, "accept");
+
+		if (read(accepted, &buffer, sizeof(buffer)) == -1)
+			error(-1, errno, "read");
+		close(accepted);
+	}
+}
+
+static void sig_handler(int signum)
+{
+	kill(SIGTERM, child_pid);
+	exit(0);
+}
+
+int main(int argc, char const *argv[])
+{
+	int sock;
+	int opt = 1;
+	struct sockaddr_in address;
+	struct sockaddr_in laddr;
+	socklen_t len = sizeof(laddr);
+
+	if (signal(SIGTERM, sig_handler) == SIG_ERR)
+		error(-1, errno, "signal");
+
+	sock = socket(AF_INET, SOCK_STREAM, 0);
+	if (sock < 0)
+		error(-1, errno, "socket");
+
+	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT,
+				&opt, sizeof(opt)) == -1)
+		error(-1, errno, "setsockopt");
+
+	address.sin_family = AF_INET;
+	address.sin_addr.s_addr = INADDR_ANY;
+	/* dynamically allocate unused port */
+	address.sin_port = 0;
+
+	if (bind(sock, (struct sockaddr *)&address, sizeof(address)) < 0)
+		error(-1, errno, "bind");
+
+	if (listen(sock, 3) < 0)
+		error(-1, errno, "listen");
+
+	if (getsockname(sock, (struct sockaddr *)&laddr, &len) == -1)
+		error(-1, errno, "getsockname");
+
+	fprintf(stderr, "server port: %d\n", ntohs(laddr.sin_port));
+	child_pid = fork();
+	if (!child_pid)
+		client(ntohs(laddr.sin_port));
+	else
+		server(sock, laddr);
+
+	return 0;
+}