网络编程 day6.2~day8——IO模型分类、超时检测、抓包分析

笔记脑图

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）。

select函数

cpp 复制代码

#include <stdio.h>
#include <string.h>
#include <myhead.h>
#define IP "192.168.110.44"
#define PORT 6666
#define BACKLOG 20
int main(int argc, const char *argv[])
{
	//创建
	int oldfd=socket(AF_INET,SOCK_STREAM,0);
	if(oldfd==-1)
	{
		perror("socket");
		return -1;
	}
	//绑定
	struct sockaddr_in server={
		.sin_family=AF_INET,
		.sin_port=htons(PORT),
		.sin_addr.s_addr=inet_addr(IP),
	};
	if(bind(oldfd,(struct sockaddr *)&server,sizeof(server))==-1)
	{
		perror("bind");
		return -1;
	}
	//监听
	if(listen(oldfd,BACKLOG)==-1)
	{
		perror("listen");
		return -1;
	}
	//接收通信
	struct sockaddr_in client;
	socklen_t client_len=sizeof(client);
	//1-1定义容器
	fd_set readfds,temp;
	FD_ZERO(&readfds);
	FD_SET(0,&readfds);
	FD_SET(oldfd,&readfds);
	int maxfd=oldfd;

	int newfd;

	while(1)//循环连入
	{
		//监视
		temp=readfds;
		int res=select(maxfd+1,&temp,NULL,NULL,NULL);
		if(res==-1)
		{
			perror("select");
			return -1;
		}
		if(res==0)
		{
			printf("超时\n");
			continue;
		}
		//检测谁发生IO操作
		int i;
		for(i=0;i<=maxfd;i++)
		{
			if(FD_ISSET(i,&temp))
			{
				continue;
			}
			else if(i==oldfd)
			{
				newfd=accept(i,(struct sockaddr *)&client,&client_len);
				FD_SET(newfd,&readfds);
				maxfd=newfd>maxfd?newfd:maxfd;
				if(newfd==-1)
				{
					perror("accept");
					return -1;
				}
				printf("%s发来连接请求\n",inet_ntoa(client.sin_addr));
			}
			else
			{
				//循环收发
				char buff[1024];

				memset(buff,0,sizeof(buff));
				int len=recv(i,buff,sizeof(buff),0);
				if(len==0)
				{
					close(i);
					FD_CLR(i,&readfds);
					if(maxfd==i)
					{
						maxfd--;
					}
					printf("客户端下线\n");
					break;
				}
				printf("%s\n",buff);
				fgets(buff,sizeof(buff),stdin);
				send(newfd,buff,sizeof(buff),0);
			}

		}
	}
	//关闭
	close(oldfd);
	return 0;
}

poll函数

cpp 复制代码

#include <poll.h>
#include <myhead.h>
#define IP "192.168.110.53"
#define PORT 6666
#define BACKLOG 20
int main(int argc, const char *argv[])
{
	//创建
	int oldfd=socket(AF_INET,SOCK_STREAM,0);
	if(oldfd==-1)
	{
		perror("socket");
		return -1;
	}
	//绑定
	struct sockaddr_in server={
		.sin_family=AF_INET,
		.sin_port=htons(PORT),
		.sin_addr.s_addr=inet_addr(IP),
	};
	if(bind(oldfd,(struct sockaddr *)&server,sizeof(server))==-1)
	{
		perror("bind");
		return -1;
	}
	//监听
	if(listen(oldfd,BACKLOG)==-1)
	{
		perror("listen");
		return -1;
	}
	//1-1设置结构体检测
	struct pollfd fds[100];
	fds[0].fd=oldfd;
	fds[0].events=POLLIN;
	//接收通信
	struct sockaddr_in client;
	socklen_t client_len=sizeof(client);
	int newfd;
	//1-2检测描述符
	int i;
	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;//创建新描述符
			fds[count].events=POLLIN;
			count++;
		}
		//循环收发
		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,"5201314");
				send(fds[i].fd,buff,sizeof(buff),0);
			}
		}
	}
	//关闭
	close(fds[0].fd);
	return 0;
}