Commit af8c8a45 authored by SeongJae Park's avatar SeongJae Park Committed by Jakub Kicinski

selftests: net: Add FIN_ACK processing order related latency spike test

This commit adds a test for FIN_ACK process races related reconnection
latency spike issues.  The issue has described and solved by the
previous commit ("tcp: Reduce SYN resend delay if a suspicous ACK is
received").

The test program is configured with a server and a client process.  The
server creates and binds a socket to a port that dynamically allocated,
listen on it, and start a infinite loop.  Inside the loop, it accepts
connection, reads 4 bytes from the socket, and closes the connection.
The client is constructed as an infinite loop.  Inside the loop, it
creates a socket with LINGER and NODELAY option, connect to the server,
send 4 bytes data, try read some data from server.  After the read()
returns, it measure the latency from the beginning of this loop to this
point and if the latency is larger than 1 second (spike), print a
message.
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarSeongJae Park <sjpark@amazon.de>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 9603d47b
...@@ -22,3 +22,4 @@ ipv6_flowlabel_mgr ...@@ -22,3 +22,4 @@ ipv6_flowlabel_mgr
so_txtime so_txtime
tcp_fastopen_backup_key tcp_fastopen_backup_key
nettest nettest
fin_ack_lat
...@@ -11,6 +11,7 @@ TEST_PROGS += udpgso_bench.sh fib_rule_tests.sh msg_zerocopy.sh psock_snd.sh ...@@ -11,6 +11,7 @@ TEST_PROGS += udpgso_bench.sh fib_rule_tests.sh msg_zerocopy.sh psock_snd.sh
TEST_PROGS += udpgro_bench.sh udpgro.sh test_vxlan_under_vrf.sh reuseport_addr_any.sh TEST_PROGS += udpgro_bench.sh udpgro.sh test_vxlan_under_vrf.sh reuseport_addr_any.sh
TEST_PROGS += test_vxlan_fdb_changelink.sh so_txtime.sh ipv6_flowlabel.sh TEST_PROGS += test_vxlan_fdb_changelink.sh so_txtime.sh ipv6_flowlabel.sh
TEST_PROGS += tcp_fastopen_backup_key.sh fcnal-test.sh l2tp.sh traceroute.sh TEST_PROGS += tcp_fastopen_backup_key.sh fcnal-test.sh l2tp.sh traceroute.sh
TEST_PROGS += fin_ack_lat.sh
TEST_PROGS_EXTENDED := in_netns.sh TEST_PROGS_EXTENDED := in_netns.sh
TEST_GEN_FILES = socket nettest TEST_GEN_FILES = socket nettest
TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any
...@@ -18,6 +19,7 @@ TEST_GEN_FILES += tcp_mmap tcp_inq psock_snd txring_overwrite ...@@ -18,6 +19,7 @@ TEST_GEN_FILES += tcp_mmap tcp_inq psock_snd txring_overwrite
TEST_GEN_FILES += udpgso udpgso_bench_tx udpgso_bench_rx ip_defrag TEST_GEN_FILES += udpgso udpgso_bench_tx udpgso_bench_rx ip_defrag
TEST_GEN_FILES += so_txtime ipv6_flowlabel ipv6_flowlabel_mgr TEST_GEN_FILES += so_txtime ipv6_flowlabel ipv6_flowlabel_mgr
TEST_GEN_FILES += tcp_fastopen_backup_key TEST_GEN_FILES += tcp_fastopen_backup_key
TEST_GEN_FILES += fin_ack_lat
TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa
TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict tls TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict tls
......
// 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;
}
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
#
# Test latency spikes caused by FIN/ACK handling race.
set +x
set -e
tmpfile=$(mktemp /tmp/fin_ack_latency.XXXX.log)
cleanup() {
kill $(pidof fin_ack_lat)
rm -f $tmpfile
}
trap cleanup EXIT
do_test() {
RUNTIME=$1
./fin_ack_lat | tee $tmpfile &
PID=$!
sleep $RUNTIME
NR_SPIKES=$(wc -l $tmpfile | awk '{print $1}')
if [ $NR_SPIKES -gt 0 ]
then
echo "FAIL: $NR_SPIKES spikes detected"
return 1
fi
return 0
}
do_test "30"
echo "test done"
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