DAY5网络

1.用select实现TCP客户端程序

#include <head.h>
#define PORT 9999 // 服务器端口号
#define IP "192.168.125.74" // 服务器IP地址

#define CIP "192.168.125.74" // 客户端
#define CPORT 6666

int main(int argc, const char* argv[])
{
    // 创建套接字
    int cfd = -1;
    if ((cfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket error\n");
        return -1;
    }
    // 端口快速重用
    int reus = 1;
    if ((reus = setsockopt(cfd, SOL_SOCKET, SO_REUSEADDR, &reus, sizeof(reus))) == -1) {
        perror("setsockopt error\n");
        return -1;
    }
    // 定义地址信息结构体
    struct sockaddr_in cin;
    cin.sin_family = AF_INET;
    cin.sin_port = htons(CPORT);
    cin.sin_addr.s_addr = inet_addr(CIP);
    // 绑定(非必须)
    if (bind(cfd, (struct sockaddr*)&cin, sizeof(cin)) == -1) {
        perror("bind error\n");
        return -1;
    }
    printf("bind success\n");
    // 定义服务器地址信息结构体
    struct sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_port = htons(PORT);
    sin.sin_addr.s_addr = inet_addr(IP);
    // 向客户端发送连接请求
    if (connect(cfd, (struct sockaddr*)&sin, sizeof(sin)) == -1) {
        perror("connect error");
        return -1;
    }
    // 定义检测描述符集合
    fd_set readfds;
    // 清0
    FD_ZERO(&readfds);

    // 将0、cfd放入集合
    FD_SET(0, &readfds);
    FD_SET(cfd, &readfds);
    // 收发数据
    char buf[128] = ""; // 容器
    fd_set temp; //
    int res = -1;
    while (1) {
        temp = readfds;
        res = select(cfd + 1, &temp, NULL, NULL, NULL);
        if (res < 0) {
            perror("select error");
            return -1;
        } else if (res == 0) {
            printf("time out\n");
            return -1;
        }
        if (FD_ISSET(0, &temp)) {
            bzero(buf, sizeof(buf)); // 清零
            fgets(buf, sizeof(buf), stdin);
            buf[strlen(buf) - 1] = 0;
            send(cfd, buf, sizeof(buf), 0);
        }
        if (FD_ISSET(cfd, &temp)) {
            bzero(buf, sizeof(buf)); // 清零
            int res = recv(cfd, buf, sizeof(buf), 0);
            if(res == 0)
            {
                printf("服务器下线\n");
                break;
            }
            printf("收到服务器消息:%s\n", buf);
        }
    }
    // 关闭
    close(cfd);
    return 0;
}

2.用poll实现服务器

#include <head.h>
#define PORT 9999
#define IP "192.168.125.74"
int main(int argc, const char *argv[])
{
	int sfd=-1;
	if((sfd=socket(AF_INET,SOCK_STREAM,0))==-1)
	{
		perror("socket error");
		return -1;
	}
	int reuse=1;
	if(setsockopt(sfd,SOL_SOCKET,SO_REUSEADDR,&reuse,sizeof(reuse))==-1)
	{
		perror("setsockopt error");
		return-1;
	}
	struct sockaddr_in sin;
	sin.sin_family=AF_INET;
	sin.sin_port=htons(PORT);
	sin.sin_addr.s_addr=inet_addr(IP);
	if(bind(sfd,(struct sockaddr*)&sin,sizeof(sin))==-1)
	{
		perror("bind error");
		return -1;
	}
	if(listen(sfd,128)==-1)
	{
		perror("listen error");
		return -1;
	}
	struct sockaddr_in cin;
	socklen_t len=sizeof(cin);
	struct sockaddr_in sock[1024];
	char ok[50];
	int newfd=-1;
	int maxfd=4;
	struct pollfd fds[1024];
	fds[0].fd=0;
	fds[0].events=POLLIN;
	fds[1].fd=sfd;
	fds[1].events=POLLIN;
	int count=2;
	puts("准备就绪");
	while(1)
	{
		if(poll(fds,count,-1)==-1)
		{
			perror("poll error");
			return -1;
		}
		for(int i=0;i<count;i++)
		{	
			if(fds[i].revents!=POLLIN)
			{
				continue;
			}
			if(i==0)
			{
				scanf("%s",ok);
				printf("终端输入%s\n",ok);
				if(strcmp(ok,"quit")==0)
					goto aa;
				for(int j=2;j<count;j++)
				{
					send(fds[j].fd,ok,sizeof(ok),0);
				}
			}
			else if(i==1)
			{
				if((newfd=accept(sfd,(struct sockaddr*)&cin,&len))==-1)
				{
					perror("accept error");
					return -1;
				}
				printf("[%s-%d]:连接成功,newfd=%d\n",inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),newfd);
				fds[count].fd=newfd;
				fds[count].events=POLLIN;
				count++;
				sock[newfd]=cin;
			}
			else
			{
				char buf[128]="";
				int res=recv(fds[i].fd,buf,sizeof(buf),0);
				if(res==0)
				{
					close(fds[i]);
					printf("[%s-%d]:退出\n",inet_ntoa(sock[fds[i].fd].sin_addr),ntohs(sock[fds[i].fd].sin_port));
					fds[i]=fds[count--];
					continue;
				}
				printf("[%s-%d]:%s\n",inet_ntoa(sock[fds[i].fd].sin_addr),ntohs(sock[fds[i].fd].sin_port),buf);
				strcat(buf,"sb");
				send(fds[i].fd,buf,sizeof(buf),0);
			}
		}
	}
aa:
	close(sfd);
	return 0;
}

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