/* TCPtecho.c - main, TCPtecho, reader, writer, mstime */#include <sys/types.h>#include <sys/param.h>#include <sys/ioctl.h>#include <sys/time.h>#include <sys/socket.h>#include <unistd.h>#include <stdlib.h>#include <string.h>#include <stdio.h>extern int	errno;int	TCPtecho(fd_set *pafds, int nfds, int ccount, int hcount);int	reader(int fd, fd_set *pfdset);int	writer(int fd, fd_set *pfdset);int	errexit(const char *format, ...);int	connectTCP(const char *host, const char *service);long	mstime(unsigned long *);#define	BUFSIZE		4096		/* write buffer size		*/#define	CCOUNT		64*1024		/* default character count	*/#define	USAGE	"usage: TCPtecho [ -c count ] host1 host2...\n"char	*hname[NOFILE];			/* fd to host name mapping	*/int	rc[NOFILE], wc[NOFILE];		/* read/write character counts	*/char	buf[BUFSIZE];			/* read/write data buffer	*//*------------------------------------------------------------------------ * main - concurrent TCP client for ECHO service timing *------------------------------------------------------------------------ */intmain(int argc, char *argv[]){	int	ccount = CCOUNT;	int	i, hcount, maxfd, fd;	int	one = 1;	fd_set	afds;	hcount = 0;	maxfd = -1;	for (i=1; i<argc; ++i) {		if (strcmp(argv[i], "-c") == 0) {			if (++i < argc && (ccount = atoi(argv[i])))				continue;			errexit(USAGE);		}		/* else, a host */		fd = connectTCP(argv[i], "echo");		if (ioctl(fd, FIONBIO, (char *)&one))			errexit("can't mark socket nonblocking: %s\n",				strerror(errno));		if (fd > maxfd)			maxfd = fd;		hname[fd] = argv[i];		++hcount;		FD_SET(fd, &afds);	}	TCPtecho(&afds, maxfd+1, ccount, hcount);	exit(0);}/*------------------------------------------------------------------------ * TCPtecho - time TCP ECHO requests to multiple servers *------------------------------------------------------------------------ */intTCPtecho(fd_set *pafds, int nfds, int ccount, int hcount){	fd_set	rfds, wfds;		/* read/write fd sets		*/	fd_set	rcfds, wcfds;		/* read/write fd sets (copy)	*/	int	fd, i;	for (i=0; i<BUFSIZE; ++i)	/* echo data	*/		buf[i] = 'D';	memcpy(&rcfds, pafds, sizeof(rcfds));	memcpy(&wcfds, pafds, sizeof(wcfds));	for (fd=0; fd<nfds; ++fd)		rc[fd] = wc[fd] = ccount;	(void) mstime((unsigned long *)0);	/* set the epoch */	while (hcount) {		memcpy(&rfds, &rcfds, sizeof(rfds));		memcpy(&wfds, &wcfds, sizeof(wfds));		if (select(nfds, &rfds, &wfds, (fd_set *)0,				(struct timeval *)0) < 0)			errexit("select failed: %s\n", strerror(errno));		for (fd=0; fd<nfds; ++fd) {			if (FD_ISSET(fd, &rfds))				if (reader(fd, &rcfds) == 0)					hcount--;			if (FD_ISSET(fd, &wfds))				writer(fd, &wcfds);		}	}}/*------------------------------------------------------------------------ * reader - handle ECHO reads *------------------------------------------------------------------------ */intreader(int fd, fd_set *pfdset){	unsigned long	now;	int		cc;	cc = read(fd, buf, sizeof(buf));	if (cc < 0)		errexit("read: %s\n", strerror(errno));	if (cc == 0)		errexit("read: premature end of file\n");	rc[fd] -= cc;	if (rc[fd])		return 1;	(void) mstime(&now);	printf("%s: %d ms\n", hname[fd], now);	(void) close(fd);	FD_CLR(fd, pfdset);	return 0;}/*------------------------------------------------------------------------ * writer - handle ECHO writes *------------------------------------------------------------------------ */intwriter(int fd, fd_set *pfdset){	int	cc;	cc = write(fd, buf, MIN((int)sizeof(buf), wc[fd]));	if (cc < 0)		errexit("read: %s\n", strerror(errno));	wc[fd] -= cc;	if (wc[fd] == 0) {		(void) shutdown(fd, 1);		FD_CLR(fd, pfdset);	}}/*------------------------------------------------------------------------ * mstime - report the number of milliseconds elapsed *------------------------------------------------------------------------ */longmstime(unsigned long *pms){	static struct timeval	epoch;	struct timeval		now;	if (gettimeofday(&now, (struct timezone *)0))		errexit("gettimeofday: %s\n", strerror(errno));	if (!pms) {		epoch = now;		return 0;	}	*pms = (now.tv_sec - epoch.tv_sec) * 1000;	*pms += (now.tv_usec - epoch.tv_usec + 500)/ 1000;	return *pms;}