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af8c8a450b
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: Eric Dumazet <edumazet@google.com>
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
151 lines
3.3 KiB
C
151 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <arpa/inet.h>
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#include <errno.h>
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#include <error.h>
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#include <netinet/in.h>
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#include <netinet/tcp.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <unistd.h>
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static int child_pid;
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static unsigned long timediff(struct timeval s, struct timeval e)
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{
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unsigned long s_us, e_us;
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s_us = s.tv_sec * 1000000 + s.tv_usec;
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e_us = e.tv_sec * 1000000 + e.tv_usec;
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if (s_us > e_us)
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return 0;
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return e_us - s_us;
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}
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static void client(int port)
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{
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int sock = 0;
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struct sockaddr_in addr, laddr;
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socklen_t len = sizeof(laddr);
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struct linger sl;
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int flag = 1;
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int buffer;
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struct timeval start, end;
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unsigned long lat, sum_lat = 0, nr_lat = 0;
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while (1) {
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gettimeofday(&start, NULL);
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sock = socket(AF_INET, SOCK_STREAM, 0);
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if (sock < 0)
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error(-1, errno, "socket creation");
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sl.l_onoff = 1;
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sl.l_linger = 0;
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if (setsockopt(sock, SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)))
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error(-1, errno, "setsockopt(linger)");
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if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY,
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&flag, sizeof(flag)))
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error(-1, errno, "setsockopt(nodelay)");
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addr.sin_family = AF_INET;
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addr.sin_port = htons(port);
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if (inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr) <= 0)
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error(-1, errno, "inet_pton");
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if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
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error(-1, errno, "connect");
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send(sock, &buffer, sizeof(buffer), 0);
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if (read(sock, &buffer, sizeof(buffer)) == -1)
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error(-1, errno, "waiting read");
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gettimeofday(&end, NULL);
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lat = timediff(start, end);
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sum_lat += lat;
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nr_lat++;
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if (lat < 100000)
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goto close;
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if (getsockname(sock, (struct sockaddr *)&laddr, &len) == -1)
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error(-1, errno, "getsockname");
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printf("port: %d, lat: %lu, avg: %lu, nr: %lu\n",
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ntohs(laddr.sin_port), lat,
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sum_lat / nr_lat, nr_lat);
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close:
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fflush(stdout);
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close(sock);
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}
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}
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static void server(int sock, struct sockaddr_in address)
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{
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int accepted;
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int addrlen = sizeof(address);
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int buffer;
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while (1) {
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accepted = accept(sock, (struct sockaddr *)&address,
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(socklen_t *)&addrlen);
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if (accepted < 0)
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error(-1, errno, "accept");
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if (read(accepted, &buffer, sizeof(buffer)) == -1)
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error(-1, errno, "read");
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close(accepted);
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}
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}
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static void sig_handler(int signum)
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{
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kill(SIGTERM, child_pid);
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exit(0);
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}
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int main(int argc, char const *argv[])
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{
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int sock;
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int opt = 1;
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struct sockaddr_in address;
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struct sockaddr_in laddr;
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socklen_t len = sizeof(laddr);
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if (signal(SIGTERM, sig_handler) == SIG_ERR)
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error(-1, errno, "signal");
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sock = socket(AF_INET, SOCK_STREAM, 0);
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if (sock < 0)
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error(-1, errno, "socket");
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if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT,
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&opt, sizeof(opt)) == -1)
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error(-1, errno, "setsockopt");
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address.sin_family = AF_INET;
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address.sin_addr.s_addr = INADDR_ANY;
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/* dynamically allocate unused port */
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address.sin_port = 0;
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if (bind(sock, (struct sockaddr *)&address, sizeof(address)) < 0)
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error(-1, errno, "bind");
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if (listen(sock, 3) < 0)
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error(-1, errno, "listen");
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if (getsockname(sock, (struct sockaddr *)&laddr, &len) == -1)
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error(-1, errno, "getsockname");
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fprintf(stderr, "server port: %d\n", ntohs(laddr.sin_port));
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child_pid = fork();
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if (!child_pid)
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client(ntohs(laddr.sin_port));
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else
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server(sock, laddr);
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return 0;
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}
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