Program to benchmark client

client.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <sys/wait.h>
#include <netdb.h>

void create_children(int nprocs, int parent_pid)
{
	while (nprocs-- > 0) {
		if (getpid() == parent_pid && fork() < 0)
			exit(1);
	}
}

int main(int argc, char *argv[])
{
	int fd, count, nprocs, parent_pid = getpid();
	struct sockaddr_in server;
	struct hostent *server_ent;
	const struct linger nolinger = { .l_onoff = 1, .l_linger = 0 };

	if (argc != 5) {
		fprintf(stderr, "Server-IP Port# #Processes #Conns_per_Proc\n");
		return 1;
	}

	nprocs = atoi(argv[3]);
	count = atoi(argv[4]);

	if ((server_ent = gethostbyname(argv[1])) == NULL) {
		perror("gethostbyname");
		return 1;
	}

	bzero((char *)&server, sizeof server);
	server.sin_family = AF_INET;
	server.sin_port   = htons(atoi(argv[2]));
	bcopy((char *)server_ent->h_addr, (char *)&server.sin_addr.s_addr,
	server_ent->h_length);

	create_children(nprocs, parent_pid);

	if (getpid() == parent_pid) {
	     	/* Parent does nothing other than wait for children */
		while (wait(NULL) != -1);
	} else {
	       	/* while the children connect() ‘count’ times to the server */
		while (count-- > 0) {
			if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
				perror("socket");
				return 1;
			}

			if (connect(fd, (struct sockaddr *)&server, sizeof server) < 0) {
				perror("connect");
				return 1;
			}

			/* Reset connection to avoid TIME-WAIT state */
			setsockopt(fd, SOL_SOCKET, SO_LINGER, &nolinger, sizeof nolinger);
			close(fd);
		}
	}

	return 0;
}