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作业2：完成局域网CS模型，局域网内一个服务器，多个客户端连接一个服务器，完成局域网聊天（select函数，poll函数，完成TCP并发服务器）。
poll函数应用：
服务器部分代码：
//TCP服务器
#include<myhead.h>
#include<poll.h>
#define IP "192.168.60.68"
#define PORT 1028
#define BACKLOG 20
int main(int argc, const char *argv[])
{//AF_INET:IPv4通信int oldfd=socket(AF_INET,SOCK_STREAM,0);if(oldfd==-1){perror("socket");return -1;}int n=1;int res=setsockopt(oldfd,SOL_SOCKET,SO_REUSEADDR,&n,sizeof(n));if(res==0){printf("端口号快速复用成功\n");}//2、绑定IP和端口号struct sockaddr_in server={.sin_family=AF_INET,//IPv4.sin_port=htons(PORT),//端口号转为网络字节序.sin_addr.s_addr=inet_addr(IP),//IP地址};if(bind(oldfd,(struct sockaddr *)&server,sizeof(server))==-1){perror("bind");return -1;}//3、监听if(listen(oldfd,BACKLOG)==-1){perror("listen");return -1;}//4、接受客户端连接请求创建新的描述符用于通信//1-1设置结构体数组检测描述符发生事件struct pollfd fds[100];fds[0].fd=oldfd;//旧的套接字描述符检测数组中fds[0].events=POLLIN;int i;struct sockaddr_in client;socklen_t client_len=sizeof(client);int newfd;int count=1;while(1){int res=poll(fds,100,-1);if(res==-1){perror("poll");}if(res==0){printf("超时\n");}if(fds[0].revents==POLLIN){newfd=accept(oldfd,(struct sockaddr *)&client,&client_len);if(newfd==-1){perror("accept");return -1;}printf("%s发来连接请求\n",inet_ntoa(client.sin_addr));fds[count].fd=newfd;fds[count++].events=POLLIN;}for(i=1;i<100;i++){if(fds[i].fd>0&&fds[i].revents==POLLIN){char buff[1024];memset(buff,0,sizeof(buff));int len=recv(fds[i].fd,buff,sizeof(buff),0);if(len==0){printf("客户端下线\n");close(fds[i].fd);break;}printf("%s\n",buff);strcat(buff,"今天是周一");send(fds[i].fd,buff,sizeof(buff),0);}}}close(oldfd);return 0;
}
客户端代码部分：
//TCP客户端
#include<myhead.h>
#define IP "192.168.60.68"
#define PORT 1028
int main(int argc, const char *argv[])
{//1、创建套接字int oldfd=socket(AF_INET,SOCK_STREAM,0);if(oldfd==-1){perror("socket");return -1;}struct sockaddr_in server={.sin_family=AF_INET,.sin_port = htons(PORT),.sin_addr.s_addr =inet_addr(IP),};if(connect(oldfd,(struct sockaddr *)&server,sizeof(server))==-1){perror("connect");return -1;}char buff[1024];while(1){fgets(buff,sizeof(buff),stdin);send(oldfd,buff,sizeof(buff),0);int len=recv(oldfd,buff,sizeof(buff),0);if(len==0){perror("服务意外退出\n");break;}printf("接受服务器消息：%s\n",buff);}close(oldfd);return 0;
}
效果演示：
selsect函数部分：
代码效果：
服务器部分：
#include <myhead.h>
#define IP "192.168.60.68"
#define PORT 1028
#define BACKLOG 20int main(int argc, const char *argv[])
{//AF_INET:IPV4通信//SOCK_STREAM：TCP通信协议int oldfd = socket(AF_INET,SOCK_STREAM,0);//1、创建套接字if(oldfd==-1){perror("socket");return -1;}//2、绑定IP和端口号struct sockaddr_in server = {.sin_family = AF_INET,//IPV4.sin_port = htons(PORT),//端口号转为网络字节序.sin_addr.s_addr = inet_addr(IP),//IP地址};if(bind(oldfd,(struct sockaddr *)&server,sizeof(server))==-1){perror("bind");return -1;}//3、监听if(listen(oldfd,BACKLOG)==-1){perror("listen");return -1;}//4、接受客户端连接请求创建新的描述符用于通信struct sockaddr_in client;//接收客户端信息的结构体socklen_t client_len = sizeof(client);//计算出结构体大小//1-1定义容器放入描述符fd_set readfds,temp;//定义两个集合存放描述符FD_ZERO(&readfds);//清空集合内的内容FD_SET(0,&readfds);FD_SET(oldfd,&readfds);//描述符放入集合int maxfd = oldfd;//保留最大的描述符int newfd;while(1)//循环连入多个客户端{//1-2监视所有的描述符temp = readfds;int res = select(maxfd+1,&temp,NULL,NULL,NULL);//永久阻塞if(res==-1){perror("select");return -1;}if(res==0){printf("超时\n");continue;}//程序执行到此，说明某些描述符解除了阻塞 //1-3循环检测是谁发生了IO操作 int i;for(i = 0;i<=maxfd;i++){if(!FD_ISSET(i,&temp))//如果描述符不在容器中，继续下次循环查找{continue;}if(i==oldfd)//旧的描述符解除的阻塞{newfd = accept(i,(struct sockaddr *)&client,&client_len);FD_SET(newfd,&readfds);//产生新描述符代表新客户端，需要放入集合maxfd = newfd>maxfd?newfd:maxfd;//更新最大的描述符if(newfd==-1){perror("accept");return -1;}printf("%s发来连接请求\n",inet_ntoa(client.sin_addr));} else//0号描述符解除的阻塞，进行通话{//5、循环收发信息char buff[1024];memset(buff,0,sizeof(buff));int len = recv(i,buff,sizeof(buff),0);//0:阻塞发送 MSG_DONTWAIT：非阻塞if(len==0){close(i);//关闭新的描述符FD_CLR(i,&readfds);//移除退出的客户端描述符if(maxfd==i)//退出后，描述符个数减一{maxfd--;}printf("客户端下线\n");break;}printf("%s\n",buff);fgets(buff,sizeof(buff),stdin);send(i,buff,sizeof(buff),0);}}}close(oldfd);return 0;
}
客户端部分：
//TCP客户端
#include<myhead.h>
#define IP "192.168.60.68"
#define PORT 1028
int main(int argc, const char *argv[])
{//1、创建套接字int oldfd=socket(AF_INET,SOCK_STREAM,0);if(oldfd==-1){perror("socket");return -1;}struct sockaddr_in server={.sin_family=AF_INET,.sin_port = htons(PORT),.sin_addr.s_addr =inet_addr(IP),};if(connect(oldfd,(struct sockaddr *)&server,sizeof(server))==-1){perror("connect");return -1;}char buff[1024];while(1){fgets(buff,sizeof(buff),stdin);send(oldfd,buff,sizeof(buff),0);int len=recv(oldfd,buff,sizeof(buff),0);if(len==0){perror("服务意外退出\n");break;}printf("接受服务器消息：%s\n",buff);}close(oldfd);return 0;
}