- TCP服务器的实现流程:
- 一、创建套接字(socket函数):
- 通信域选择IPV4网络协议、套接字类型选择流式;
int sockfd = socket(AF_INET,SOCK_STREAM,0);
- 二、填充服务器的网络信息结构体:
- 1.定义网络信息结构体变量;
- 2.求出结构体变量的内存空间大小;
- 3.结构体清零;
- 4.使用IPV4网络协议;
- 5.预留给在终端输入的网络字节序的端口号;
- 6.预留给在终端输入的IP地址;
struct sockaddr_in serveraddr; socklen_t serveraddrlen = sizeof(serveraddr);memset(&serveraddr,0,serveraddrlen); serveraddr.sin_family = AF_INET; serveraddr.sin_addr.s_addr = inet_addr(argv[1]); serveraddr.sin_port = htons(atoi(argv[2]));
- 三、套接字和服务器的网络信息结构体进行绑定(bind函数):
int ret = bind(sockfd,(struct sockaddr *)&serveraddr,serveraddrlen);
int ret1 = listen(sockfd, 5);
int acceptfd = accept(sockfd, (struct sockaddr *)&clientaddr, &clientaddr_len);
- 六、接收来自客户端的数据(recv函数)和给客户端发送应答消息(send函数):
int nbytes = recv(acceptfd,buf,sizeof(buf),0);printf("客户端发来数据[%s]\n",buf);strcat(buf,"----k"); int ret2 = send(acceptfd,buf,sizeof(buf),0);
close(acceptfd);close(sockfd);
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>#define ERRLOG(msg) do{\printf("%s:%s:%d\n", __FILE__, __func__, __LINE__);\perror(msg);\exit(-1);\}while(0)int main(int argc, char const *argv[])
{if(3 != argc){printf("Usage : %s <IP> <port>\n",argv[0]);exit(-1);}int sockfd = socket(AF_INET,SOCK_STREAM,0);if(-1 == sockfd){ERRLOG("socket error");}printf("sockfd = %d\n",sockfd);struct sockaddr_in serveraddr;socklen_t serveraddrlen = sizeof(serveraddr);memset(&serveraddr,0,serveraddrlen);serveraddr.sin_family = AF_INET;serveraddr.sin_addr.s_addr = inet_addr(argv[1]);serveraddr.sin_port = htons(atoi(argv[2]));if(-1 == bind(sockfd,(struct sockaddr *)&serveraddr,serveraddrlen)){ERRLOG("bind error");}if(-1 == listen(sockfd,5)){ERRLOG("listen error");}struct sockaddr_in clientaddr;memset(&clientaddr,0,sizeof(clientaddr));socklen_t clientaddr_len = sizeof(clientaddr);int acceptfd = 0;char buf[128] = {0};int nbytes = 0;while(1){printf("正在等待客户机连接服务器\n");if(-1 == (acceptfd = accept(sockfd,(struct sockaddr *)&clientaddr,&clientaddr_len))){ERRLOG("accept error");}printf("客户端[%s:%d]连接到了服务器\n",inet_ntoa(clientaddr.sin_addr),ntohs(clientaddr.sin_port));while(1){memset(buf,0,sizeof(buf));if(-1 == (nbytes = recv(acceptfd,buf,128,0))){ERRLOG("recv error");}else if(0 == nbytes){printf("客户端[%s:%d]断开了服务器\n",inet_ntoa(clientaddr.sin_addr),ntohs(clientaddr.sin_port));break;}if(!strncmp(buf,"quit",4)){printf("客户端[%s:%d]退出了\n",inet_ntoa(clientaddr.sin_addr),ntohs(clientaddr.sin_port));break;}printf("客户端[%s:%d]发来数据[%s]\n",inet_ntoa(clientaddr.sin_addr),ntohs(clientaddr.sin_port),buf);strcat(buf,"----k");if(-1 == send(acceptfd,buf,sizeof(buf),0)){ERRLOG("send error");}}close(acceptfd);}close(sockfd);return 0;
}