4.17 网络编程

思维导图

select实现TCP并发服务器

#include <myhead.h>
#define SER_IP "192.168.125.26"
#define SER_PORT 8888

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

	int reuse = 1;
	if(setsockopt(sfd,SOL_SOCKET,SO_REUSEADDR,&reuse,sizeof(reuse))==-1)
	{
		perror("setsockopt error");
		return -1;
	}
	printf("端口号快速重用成功\n");

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

	if(bind(sfd,(struct sockaddr*)&sin,sizeof(sin)) == -1)
	{
		perror("bind error");
		return -1;
	}
	printf("bind success\n");

	if(listen(sfd,128) == -1)
	{
		perror("listen error");
		return -1;
	}
	printf("listen success\n");

	struct sockaddr_in cin;
	socklen_t socklen = sizeof(cin);

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

	while(1)
	{
		tempfds = readfds;

		int res = select(sfd+1,&tempfds,NULL,NULL,NULL);
		if(res == 0)
		{
			printf("time out\n");
			return -1;
		}
		else if(res ==-1)
		{
			perror("select error");
			return -1;
		}
	
		for(int i =0;i <= maxfd;i++)
		{
			if(!FD_ISSET(i,&tempfds))
			{
				continue;
			}
			if(i == sfd)
			{
				newfd = accept(sfd,(struct sockaddr*)&cin,&socklen);
				if(newfd == -1)
				{
					perror("accept error");
					return -1;
				}
				printf("[%s:%d]:已连接,newfd = %d\n",\
							inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd);
				FD_SET(newfd,&readfds);
				cin_arr[newfd] = cin;

				if(maxfd<newfd)
				{
					maxfd = newfd;
				}
			}

			else if(i == 0)
			{
				char buf[128] = "";
 	           fgets(buf, sizeof(buf), stdin);
	            buf[strlen(buf)-1] = 0;
	            printf("触发了键盘输入事件：%s\n", buf);
			}
			else
			{
				char rbuf[128] = "";       //用于接受消息
 			    bzero(rbuf, sizeof(rbuf));    //清空容器
            	//从套接字文件中读取消息
            	//int ret = read(newfd, rbuf, sizeof(rbuf));
            	int ret = recv(newfd, rbuf, sizeof(rbuf), 0);
            	if(ret == 0)
            	{
                	printf("客户端已下线\n");
                	close(1);
					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.sin_addr), ntohs(cin.sin_port),rbuf );
				for(int i=4;i<=maxfd;i++)
				{
					send(i,rbuf,strlen(rbuf),0);
				}
			}
		}
	}
	close(sfd);
	return 0;
}

poll完成TCP的客户端

#define SER_IP "192.168.125.12"
#define SER_PORT 8889
#define CLI_IP "192.168.125.12"
#define CLI_PORT 9999
int main(int argc, const char *argv[])
{
	int cfd = socket(AF_INET,SOCK_STREAM,0);
	if(cfd == -1)
	{
		perror("socket error");
		return -1;
	}
	printf("socket success cfd = %d\n",cfd);
	
	int reuse = 1;
	if(setsockopt(cfd,SOL_SOCKET,SO_REUSEADDR,&reuse,sizeof(reuse)) == -1)
	{
		perror("setsockopt error");
		return -1;
	}
	printf("端口号快速重用成功\n");
	struct sockaddr_in cin;
	cin.sin_family = AF_INET;
	cin.sin_port = htons(CLI_PORT);
	cin.sin_addr.s_addr = inet_addr(CLI_IP);

	if(bimd(cfd,(struct sockaddr*)&cin,sizeof(cin)) == -1)
	{
		perror("bind error");
		return -1;
	}
	printf("bind success\n");

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

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

	struct pollfd pfds[2];
	pfds[0].fd = cfd;
	pfds[0].events = POLLIN;

	pfds[1].fd = 0;
	pfds[1].events = POLLIN;

	char wbuf[128] = "";
	while(1)
	{
		int res = poll(pfds,2,-1);
		if(res == 0)
		{
			printf("time out\n");
			return -1;
		}
		else if(res == -1)
		{
			perror("poll error");
			return -1;
		}

		if(pfds[0].revents == POLLIN)
		{
			fgets(wbuf,sizeof(wbuf),stdin);
			wbuf[strlen(wbuf)-1] = '\0';
			if(strcmp(wbuf,"quit") == 0)
			{
				break;
			}

			send(cfd,wbuf,strlen(wbuf),0);
		}

		if(pfds[1].revents == POLLIN)
		{
			bzero(wbuf,sizeof(wbuf));
			recv(cfd,wbuf,sizeof(wbuf),0);
			printf("收到服务器的信息为：%s\n",wbuf);
		}
	}
	close(cfd);

	return 0;
}