#include
#include
#include
#include
#include
#include
#include
#define MAXBUF 512
int main(int argc, char **argv)
{
int sockfd, len;
struct sockaddr_in server_addr;
char buffer[MAXBUF + 1];
if (argc != 3) {
printf("参数正确格式如下：\nIP地址 端口\n127.0.0.1 4567\n");
exit(0);
}
/* 创建一个 socket 用于 tcp 通信 */
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("Socket");
exit(errno);
}
printf("socket created\n");
/* 初始化服务器端（对方）的地址和端口信息 */
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(atoi(argv[2]));
if (inet_aton(argv[1], (struct in_addr *) &server_addr.sin_addr.s_addr) == 0) {
perror(argv[1]);
exit(errno);
}
/* 连接服务器 */
if (connect(sockfd, (struct sockaddr *) &server_addr, sizeof(server_addr)) != 0) {
perror("Connect failure");
exit(errno);
}
printf("server connected\n");
/* 接收对方发过来的消息，最多接收 MAXBUF 个字节 */
bzero(buffer, MAXBUF + 1);
/* 接收服务器来的消息 */
len = recv(sockfd, buffer, MAXBUF, 0);
if(len > 0)
printf("接收消息成功:'%s'，共%d个字节的数据\n", buffer, len);
else
printf("消息接收失败！错误代码是%d，错误信息是'%s'\n", errno, strerror(errno));
bzero(buffer, MAXBUF + 1);
strcpy(buffer, "客户端发给服务器端的消息\n");
/* 发消息给服务器 */
len = send(sockfd, buffer, strlen(buffer), 0);
if(len < 0)
printf("发送失败！错误代码是%d，错误信息是'%s'\n", errno, strerror(errno));
else
printf("发送成功，共发送了%d个字节！\n", len);
/* 关闭连接 */
close(sockfd);
return 0;
}
4、服务器源代码（tcpserver.c）：
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define MAXBUF 512
int main(int argc, char **argv)
{
int sockfd, new_fd;
socklen_t len;
struct sockaddr_in server_addr, client_addr;
unsigned int port, num;
char buf[MAXBUF + 1];
if (argv[1])
port = atoi(argv[1]);
else
port = 5678;
if (argv[2])
num = atoi(argv[2]);
else
num = 3;
if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
else printf("socket created success!!!\n");
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = PF_INET;
server_addr.sin_port = htons(port);
if(argv[3])
server_addr.sin_addr.s_addr = inet_addr(argv[3]);
else
server_addr.sin_addr.s_addr = INADDR_ANY;
if (bind(sockfd, (struct sockaddr *) &server_addr, sizeof(struct sockaddr)) == -1) {
perror("bind");
exit(1);
}else
printf("binded success!!!\n");
if (listen(sockfd, num) == -1) {
perror("listen");
exit(1);
}else
printf("Let's listen\n");
while(1) {
len = sizeof(struct sockaddr);
if ((new_fd = accept(sockfd, (struct sockaddr *)&client_addr, &len)) == -1) {
perror("accept");
exit(errno);
}else
printf("client
connect the server now: client %s, port %d, new socket
%d\n",inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port),
new_fd);
/* 开始处理每个新连接上的数据收发 */
bzero(buf, MAXBUF + 1);
strcpy(buf, "服务器发给客户端的消息\n只能向new_fd这个用accept函数新建立的socket发消息，不能向sockfd这个监听socket发送消息，监听socket不能用来接收或发送消息\n");
/* 发消息给客户端 */
len = send(new_fd, buf, strlen(buf), 0);
if(len < 0) {
printf("消息发送失败！错误代码是%d，错误信息是'%s'\n", errno, strerror(errno));
}else
printf("消息发送成功，共发送了%d个字节！\n", len);ss
bzero(buf, MAXBUF + 1);
/* 接收客户端的消息 */
len = recv(new_fd, buf, MAXBUF, 0);
if(len > 0)
printf("接收成功:'%s'，共%d个字节的数据\n", buf, len);
else
printf("接收失败！错误代码是%d，错误信息是'%s'\n", errno, strerror(errno));
/* 处理每个新连接上的数据收发结束 */
}
close(sockfd);
return 0;
}
5、编译源代码：
new@new-desktop:~/linux/c$ gcc -Wall tcpclient.c -o tcpclient
new@new-desktop:~/linux/c$ gcc -Wall tcpserver.c -o tcpserver
6、服务器程序运行：
