TCP编程

写代码

第一步socket

绑定

先填充





点分十进制转换成32位整数

client

然后就连接成功了就可以读写数据了

client

#include "net.h"int main (void)
{int fd = -1;struct sockaddr_in sin;/* 1. 创建socket fd */if ((fd = socket (AF_INET, SOCK_STREAM, 0)) < 0) {perror ("socket");exit (1);}/*2.连接服务器 *//*2.1 填充struct sockaddr_in结构体变量 */bzero (&sin, sizeof (sin));sin.sin_family = AF_INET;sin.sin_port = htons (SERV_PORT);	//网络字节序的端口号
#if 0sin.sin_addr.s_addr = inet_addr (SERV_IP_ADDR);
#elseif (inet_pton (AF_INET, SERV_IP_ADDR, (void *) &sin.sin_addr) != 1) {perror ("inet_pton");exit (1);}
#endifif (connect (fd, (struct sockaddr *) &sin, sizeof (sin)) < 0) {perror ("connect");exit (1);}printf ("Client staring...OK!\n");/*3. 读写数据 */char buf[BUFSIZ];int ret = -1;while (1) {bzero (buf, BUFSIZ);if (fgets (buf, BUFSIZ - 1, stdin) == NULL) {continue;}do {ret = write (fd, buf, strlen (buf));} while (ret < 0 && EINTR == errno);if (!strncasecmp (buf, QUIT_STR, strlen (QUIT_STR))) {	//用户输入了quit字符printf ("Client is exiting!\n");break;}}/*4.关闭套接字 */close (fd);
}

server

#include "net.h"int main (void)
{int fd = -1;struct sockaddr_in sin;/* 1. 创建socket fd */if ((fd = socket (AF_INET, SOCK_STREAM, 0)) < 0) {perror ("socket");exit (1);}/*2. 绑定 *//*2.1 填充struct sockaddr_in结构体变量 */bzero (&sin, sizeof (sin));sin.sin_family = AF_INET;sin.sin_port = htons (SERV_PORT);	//网络字节序的端口号/*优化1: 让服务器程序能绑定在任意的IP上 */
#if 1sin.sin_addr.s_addr = htonl (INADDY_ANY);
#elseif (inet_pton (AF_INET, SERV_IP_ADDR, (void *) &sin.sin_addr) != 1) {perror ("inet_pton");exit (1);}
#endif/*2.2 绑定 */if (bind (fd, (struct sockaddr *) &sin, sizeof (sin)) < 0) {perror ("bind");exit (1);}/*3. 调用listen()把主动套接字变成被动套接字 */if (listen (fd, BACKLOG) < 0) {perror ("listen");exit (1);}printf ("Server starting....OK!\n");int newfd = -1;/*4. 阻塞等待客户端连接请求 */
#if 0newfd = accept (fd, NULL, NULL);if (newfd < 0) {perror ("accept");exit (1);}
#else/*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 */struct sockaddr_in cin;socklen_t addrlen = sizeof (cin);if ((newfd = accept (fd, (struct sockaddr *) &cin, &addrlen)) < 0) {perror ("accept");exit (1);}char ipv4_addr[16];if (!inet_ntop (AF_INET, (void *) &cin.sin_addr, ipv4_addr, sizeof (cin))) {perror ("inet_ntop");exit (1);}printf ("Clinet(%s:%d) is connected!\n", ipv4_addr, ntons (cin.sin_port));#endif/*5. 读写 *///..和newfd进行数据读写int ret = -1;char buf[BUFSIZ];while (1) {bzero (buf, BUFSIZ);do {ret = read (newfd, buf, BUFSIZ - 1);} while (ret < 0 && EINTR == errno);if (ret < 0) {perror ("read");exit (1);}if (!ret) {				//对方已经关闭break;}printf ("Receive data: %s\n", buf);if (!strncasecmp (buf, QUIT_STR, strlen (QUIT_STR))) {	//用户输入了quit字符printf ("Client is exiting!\n");break;}}close (newfd);close (fd);return 0;
}

这个是让他在任意ip上