/******* 服務器程序 (server.c) ************/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
int
main (int argc, char *argv[])
{
int sockfd, new_fd;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;
int sin_size, portnumber;
char hello[] = "Hello! Are You Fine?/n";
if (argc != 2)
{
fprintf (stderr, "Usage:%s portnumber/a/n", argv[0]);
exit (1);
}
if ((portnumber = atoi (argv[1])) < 0)
{
fprintf (stderr, "Usage:%s portnumber/a/n", argv[0]);
exit (1);
}
/* 服務器端開始建立socket描述符 */
if ((sockfd = socket (AF_INET, SOCK_STREAM, 0)) == -1)
{
fprintf (stderr, "Socket error:%s/n/a", strerror (errno));
exit (1);
}
/* 服務器端填充 sockaddr結構 */
bzero (&server_addr, sizeof (struct sockaddr_in));
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = htonl (INADDR_ANY);
server_addr.sin_port = htons (portnumber);
/* 捆綁sockfd描述符 */
if (bind
(sockfd, (struct sockaddr *) (&server_addr),
sizeof (struct sockaddr)) ==
-1)
{
fprintf (stderr, "Bind error:%s/n/a", strerror (errno));
exit (1);
}
/* 監聽sockfd描述符 */
if (listen (sockfd, 5) == -1)
{
fprintf (stderr, "Listen error:%s/n/a", strerror (errno));
exit (1);
}
while (1)
{
/* 服務器阻塞,直到客戶程序建立連接 */
sin_size = sizeof (struct sockaddr_in);
if ((new_fd =
accept (sockfd, (struct sockaddr *) (&client_addr),
&sin_size)) == -1)
{
fprintf (stderr, "Accept error:%s/n/a", strerror (errno));
exit (1);
}
fprintf (stderr, "Server get connection from %s/n",
inet_ntoa (client_addr.sin_addr));
if (write (new_fd, hello, strlen (hello)) == -1)
{
fprintf (stderr, "Write Error:%s/n", strerror (errno));
exit (1);
}
/* 這個通訊已經結束 */
close (new_fd);
/* 循環下一個 */
}
close (sockfd);
exit (0);
}
--------------------------------------------------------------
/******* 客戶端程序 client.c ************/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
int
main (int argc, char *argv[])
{
int sockfd;
char buffer[1024];
struct sockaddr_in server_addr;
struct hostent *host;
int portnumber, nbytes;
if (argc != 3)
{
fprintf (stderr, "Usage:%s hostname portnumber/a/n", argv[0]);
exit (1);
}
if ((host = gethostbyname (argv[1])) == NULL)
{
fprintf (stderr, "Gethostname error/n");
exit (1);
}
if ((portnumber = atoi (argv[2])) < 0)
{
fprintf (stderr, "Usage:%s hostname portnumber/a/n", argv[0]);
exit (1);
}
/* 客戶程序開始建立 sockfd描述符 */
if ((sockfd = socket (AF_INET, SOCK_STREAM, 0)) == -1)
{
fprintf (stderr, "Socket Error:%s/a/n", strerror (errno));
exit (1);
}
/* 客戶程序填充服務端的資料 */
bzero (&server_addr, sizeof (server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons (portnumber);
server_addr.sin_addr = *((struct in_addr *) host->h_addr);
/* 客戶程序發起連接請求 */
if (connect
(sockfd, (struct sockaddr *) (&server_addr),
sizeof (struct sockaddr)
) == -1)
{
fprintf (stderr, "Connect Error:%s/a/n", strerror (errno));
exit (1);
}
/* 連接成功了 */
if ((nbytes = read (sockfd, buffer, 1024)) == -1)
{
fprintf (stderr, "Read Error:%s/n", strerror (errno));
exit (1);
}
buffer[nbytes] = '/0';
printf ("I have received:%s/n", buffer);
/* 結束通訊 */
close (sockfd);
exit (0);
}