1
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
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}
152
