5.22 Select和Poll+思维导图

// tcp_select_ser.c
#include <sys/types.h> 
#include <sys/socket.h>
#include <string.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>

#define SER_PORT 8888
#define SER_IP "192.168.125.114"


int main(int argc, const char *argv[])
{
	//1、为通信创建一个端点
	int sfd = socket(AF_INET, SOCK_STREAM, 0);
	//参数1：说明使用的是ipv4通信域
	//参数2：说明使用的是tcp面向连接的通信方式
	//参数3：由于参数2中已经指定通信方式，填0
	if(-1 == sfd){
		perror("socket");
		return 1;
	}
	printf("socket success sfd = %d\n", sfd);

	//2、绑定ip和端口号
	//2.1、准备地址信息结构体
	struct sockaddr_in sin = {
		.sin_family = AF_INET,//通信域
		.sin_port = htons(SER_PORT),//端口号
		.sin_addr = { inet_addr(SER_IP) },//ip地址
	};

	//2.2、绑定工作
	if(-1 == bind(sfd, (struct sockaddr*)&sin, sizeof(sin))){
		perror("bind");
		return 1;
	}
	puts("bind success");

	//3、将套接字设置为被动监听状态
	if(-1 == listen(sfd, 128)){
		perror("listen");
		return 1;
	}
	puts("listen success");
	//4、阻塞等待客户端的连接
	//4.1、定义用于接受客户端信息的容器
	struct sockaddr_in cin;
	socklen_t addrlen = sizeof(cin);


	fd_set readfds, tmpfds;
	FD_ZERO(&readfds);
	FD_SET(sfd, &readfds);
	FD_SET(0, &readfds);
	int newfd = 0;
	int maxfd = sfd;
	struct sockaddr_in cin_arr[1024];

	//5、与客户端进行相互通信
	while(1){
		tmpfds = readfds;
		int retval = select(maxfd+1, &tmpfds, NULL, NULL, NULL);
		if(-1 == retval){
			perror("select");
			return 1;
		}
		else if(0 == retval){
			puts("time out");
			return 1;
		}

		for(int i = 0; i <= maxfd; i++){
			if(!FD_ISSET(i, &tmpfds))
				continue;


			if(i == sfd){
				newfd = accept(i, (struct sockaddr*)&cin, &addrlen);
				if(-1 == newfd){
					perror("accpet");
					return 1;
				}
				printf("[%s:%d]:connected!\n", inet_ntoa(cin.sin_addr),
						ntohs(cin.sin_port));
				FD_SET(newfd, &readfds);
				if(newfd >= maxfd)
					maxfd = newfd;
				cin_arr[newfd] = cin;
			}

			else if(0 == i){
				char buf[128] = "";
				fgets(buf, sizeof(buf), stdin);
				buf[strlen(buf) - 1] = '\0';
				printf("keyboard input: %s\n", buf);
				for(int k = 4; k <= maxfd; k++)
					send(k, buf, strlen(buf), 0);
			}
			else{
				char buf[128] = {};
				int ret = recv(i, buf, sizeof(buf), 0);
				if(0 == ret){
					printf("client disconnecting...\n");
					close(i);
					FD_CLR(i, &readfds);
					for(int j = maxfd; j >= sfd; j--){
						if(FD_ISSET(j, &readfds)){
							maxfd = j;
							break;
						}
					}
					continue;
				}
				printf("[%s:%d]:%s\n", inet_ntoa(cin_arr[i].sin_addr),
						ntohs(cin_arr[i].sin_port), buf);
				for(int k = 4; k <= maxfd; k++){
					if(k != i)
						send(k, buf, strlen(buf), 0);
				}
			}

		}
	}
	//6、关闭套接字
	close(sfd);
	return 0;
}

//poll.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <poll.h>
#include <arpa/inet.h>
#include <unistd.h>

#define SER_PORT 8888
#define SER_IP "192.168.125.75"
#define CLI_PORT 6666
#define CLI_IP "192.168.125.114"


int main(int argc, const char *argv[])
{
	int cfd = socket(AF_INET, SOCK_STREAM, 0);
	if(-1 == cfd){
		perror("socket error");
		return 1;
	}
	printf("cfd = %d\n", cfd);

	struct sockaddr_in cin = {
		.sin_family = AF_INET,
		.sin_port = htons(CLI_PORT),
		.sin_addr = { inet_addr(CLI_IP) },
	};

	if(bind(cfd, (struct sockaddr*)&cin, sizeof(cin)) == -1){
		perror("bind");
		return 1;
	}
	puts("bind success");

	struct sockaddr_in sin = {
		.sin_family = AF_INET,
		.sin_port = htons(SER_PORT),
		.sin_addr = { inet_addr(SER_IP) },
	};

	if(connect(cfd, (struct sockaddr*)&sin, sizeof(sin)) == -1){
		perror("connect");
		return 1;
	}
	puts("connect success");

	struct pollfd pfd[2] = {
		{ 0, POLLIN },
		{ cfd, POLLIN },
	};

	while(1){
		char buf[128] = {};
		int ret = poll(pfd, 2, -1);
		if(-1 == ret){
			perror("poll");
			return -1;
		}
		else if(0 == ret){
			puts("time out");
			return 1;
		}


		if(pfd[0].revents == POLLIN){
			fgets(buf, sizeof(buf), stdin);
			buf[strlen(buf) - 1] = '\0';
			send(cfd, buf, strlen(buf), 0);
			puts("send over");
		}

		if(pfd[1].revents == POLLIN){
			bzero(buf, sizeof(buf));
			recv(cfd, buf, sizeof(buf), 0);
			printf("server: %s\n", buf);
		}
	}
	close(cfd);

	return 0;
}