1. #include "hl.h"
    3. int main (void)
    4. {
    6.     int fd = -1;
    7.     struct sockaddr_in sin;
    9.     /* 1. 创建socket fd */
    10.     if ((fd = socket (AF_INET, SOCK_STREAM, 0)) < 0) {
    11.         perror ("socket");
    12.         exit (1);
    13.     }
    15.     /*2. 绑定 */
    16.     /*2.1 填充struct sockaddr_in结构体变量 */
    17.     bzero (&sin, sizeof (sin));
    18.     sin.sin_family = AF_INET;
    19.     sin.sin_port = htons (SERV_PORT);    //网络字节序的端口号
    21.     /*优化1: 让服务器程序能绑定在任意的IP上 */
    22. #if 1
    23.     sin.sin_addr.s_addr = htonl (INADDR_ANY);
    24. #else
    25.     if (inet_pton (AF_INET, SERV_IP_ADDR, (void *) &sin.sin_addr) != 1) {
    26.         perror ("inet_pton");
    27.         exit (1);
    28.     }
    29. #endif
    30.     /*2.2 绑定 */
    31.     if (bind (fd, (struct sockaddr *) &sin, sizeof (sin)) < 0) {
    32.         perror ("bind");
    33.         exit (1);
    34.     }
    36.     /*3. 调用listen()把主动套接字变成被动套接字 */
    37.     if (listen (fd, BACKLOG) < 0) {
    38.         perror ("listen");
    39.         exit (1);
    40.     }
    41.     printf ("Server starting....OK!\n");
    42.     int newfd = -1;
    43.     /*4. 阻塞等待客户端连接请求 */
    44. #if 0
    45.     newfd = accept (fd, NULL, NULL);
    46.     if (newfd < 0) {
    47.         perror ("accept");
    48.         exit (1);
    49.     }
    50. #else
    51.     /*优化2：通过程序获取刚建立连接的socket的客户端的IP地址和端口号 */
    52.     struct sockaddr_in cin;
    53.     socklen_t addrlen = sizeof (cin);
    54.     if ((newfd = accept (fd, (struct sockaddr *) &cin, &addrlen)) < 0) {
    55.         perror ("accept");
    56.         exit (1);
    57.     }
    59.     char ipv4_addr[16];
    60.     if (!inet_ntop (AF_INET, (void *) &cin.sin_addr, ipv4_addr, sizeof (cin))) {
    61.         perror ("inet_ntop");
    62.         exit (1);
    63.     }
    65.     printf ("Clinet(%s:%d) is connected!\n", ipv4_addr, htons (cin.sin_port));
    67. #endif
    68.     /*5. 读写 */
    69.     //..和newfd进行数据读写
    70.     int ret = -1;
    71.     char buf[BUFSIZ];
    72.     while (1) {
    73.         bzero (buf, BUFSIZ);
    74.         do {
    75.             ret = read (newfd, buf, BUFSIZ - 1);
    76.         } while (ret < 0 && EINTR == errno);
    77.         if (ret < 0) {
    79.             perror ("read");
    80.             exit (1);
    81.         }
    82.         if (!ret) {                //对方已经关闭
    83.             break;
    84.         }
    85.         printf ("Receive data: %s\n", buf);
    87.         if (!strncasecmp (buf, QUIT_STR, strlen (QUIT_STR))) {    //用户输入了quit字符
    88.             printf ("Client is exiting!\n");
    89.             break;
    90.         }
    91.     }
    92.     close (newfd);
    94.     close (fd);
    95.     return 0;
    96. }