fin_ack_lat.c

  1// SPDX-License-Identifier: GPL-2.0
  2
  3#include <arpa/inet.h>
  4#include <errno.h>
  5#include <error.h>
  6#include <netinet/in.h>
  7#include <netinet/tcp.h>
  8#include <signal.h>
  9#include <stdio.h>
 10#include <stdlib.h>
 11#include <sys/socket.h>
 12#include <sys/time.h>
 13#include <unistd.h>
 14
 15static int child_pid;
 16
 17static unsigned long timediff(struct timeval s, struct timeval e)
 18{
 19	unsigned long s_us, e_us;
 20
 21	s_us = s.tv_sec * 1000000 + s.tv_usec;
 22	e_us = e.tv_sec * 1000000 + e.tv_usec;
 23	if (s_us > e_us)
 24		return 0;
 25	return e_us - s_us;
 26}
 27
 28static void client(int port)
 29{
 30	int sock = 0;
 31	struct sockaddr_in addr, laddr;
 32	socklen_t len = sizeof(laddr);
 33	struct linger sl;
 34	int flag = 1;
 35	int buffer;
 36	struct timeval start, end;
 37	unsigned long lat, sum_lat = 0, nr_lat = 0;
 38
 39	while (1) {
 40		gettimeofday(&start, NULL);
 41
 42		sock = socket(AF_INET, SOCK_STREAM, 0);
 43		if (sock < 0)
 44			error(-1, errno, "socket creation");
 45
 46		sl.l_onoff = 1;
 47		sl.l_linger = 0;
 48		if (setsockopt(sock, SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)))
 49			error(-1, errno, "setsockopt(linger)");
 50
 51		if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY,
 52					&flag, sizeof(flag)))
 53			error(-1, errno, "setsockopt(nodelay)");
 54
 55		addr.sin_family = AF_INET;
 56		addr.sin_port = htons(port);
 57
 58		if (inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr) <= 0)
 59			error(-1, errno, "inet_pton");
 60
 61		if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
 62			error(-1, errno, "connect");
 63
 64		send(sock, &buffer, sizeof(buffer), 0);
 65		if (read(sock, &buffer, sizeof(buffer)) == -1)
 66			error(-1, errno, "waiting read");
 67
 68		gettimeofday(&end, NULL);
 69		lat = timediff(start, end);
 70		sum_lat += lat;
 71		nr_lat++;
 72		if (lat < 100000)
 73			goto close;
 74
 75		if (getsockname(sock, (struct sockaddr *)&laddr, &len) == -1)
 76			error(-1, errno, "getsockname");
 77		printf("port: %d, lat: %lu, avg: %lu, nr: %lu\n",
 78				ntohs(laddr.sin_port), lat,
 79				sum_lat / nr_lat, nr_lat);
 80close:
 81		fflush(stdout);
 82		close(sock);
 83	}
 84}
 85
 86static void server(int sock, struct sockaddr_in address)
 87{
 88	int accepted;
 89	int addrlen = sizeof(address);
 90	int buffer;
 91
 92	while (1) {
 93		accepted = accept(sock, (struct sockaddr *)&address,
 94				(socklen_t *)&addrlen);
 95		if (accepted < 0)
 96			error(-1, errno, "accept");
 97
 98		if (read(accepted, &buffer, sizeof(buffer)) == -1)
 99			error(-1, errno, "read");
100		close(accepted);
101	}
102}
103
104static void sig_handler(int signum)
105{
106	kill(SIGTERM, child_pid);
107	exit(0);
108}
109
110int main(int argc, char const *argv[])
111{
112	int sock;
113	int opt = 1;
114	struct sockaddr_in address;
115	struct sockaddr_in laddr;
116	socklen_t len = sizeof(laddr);
117
118	if (signal(SIGTERM, sig_handler) == SIG_ERR)
119		error(-1, errno, "signal");
120
121	sock = socket(AF_INET, SOCK_STREAM, 0);
122	if (sock < 0)
123		error(-1, errno, "socket");
124
125	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT,
126				&opt, sizeof(opt)) == -1)
127		error(-1, errno, "setsockopt");
128
129	address.sin_family = AF_INET;
130	address.sin_addr.s_addr = INADDR_ANY;
131	/* dynamically allocate unused port */
132	address.sin_port = 0;
133
134	if (bind(sock, (struct sockaddr *)&address, sizeof(address)) < 0)
135		error(-1, errno, "bind");
136
137	if (listen(sock, 3) < 0)
138		error(-1, errno, "listen");
139
140	if (getsockname(sock, (struct sockaddr *)&laddr, &len) == -1)
141		error(-1, errno, "getsockname");
142
143	fprintf(stderr, "server port: %d\n", ntohs(laddr.sin_port));
144	child_pid = fork();
145	if (!child_pid)
146		client(ntohs(laddr.sin_port));
147	else
148		server(sock, laddr);
149
150	return 0;
151}