网络编程基础day2

1. TCP的服务器 

#include 
#define PORT 4399 //端口号，范围1024~49151
#define IP "192.168.114.47"//本机IP ifconfig

int main(int argc, const char *argv[])
{
	//1、创建流式套接字
	int sfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sfd < 0)
	{
		ERR_MSG("socket");
		return -1;
	}

	printf("socket creat success sfd=%d\n",sfd);


	//允许端口快速被复用
    int reuse = 1;                                                            
    if(setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0)
    {
        ERR_MSG("setsockopt");
        return -1;
    }
    printf("允许端口快速复用成功\n");
	//2、绑定服务器地址信息 必须绑定 bind
	//真实的地址信息结构体根据地址族指定 AF_INET :man 7 ip 
	struct sockaddr_in sin;

	sin.sin_family = AF_INET;

	sin.sin_port = htons(PORT);//端口号网络字节序
	sin.sin_addr.s_addr = inet_addr(IP);//本机IP

	if(bind(sfd, (struct sockaddr*)&sin, sizeof(sin)) == -1 )
	{
		ERR_MSG("bind");
		return -1;
	}
	printf("bind success\n");
	//3、将套接字设置为被动监听状态 listen
	if(listen(sfd, 128) < 0)
	{
		ERR_MSG("listen");
		return -1;
	}
	printf("listen success\n");

	//4、获取一个已经完成的客户端信息，生成一个新的文件描述符 accept
	int newfd = -1;
	struct sockaddr_in cin;
	socklen_t addrlen = sizeof(cin);
	//	accept(sfd, NULL, NULL);
	newfd = accept(sfd, (struct sockaddr*)&cin, &addrlen);
	if(newfd<0)
	{
		ERR_MSG("newfd");
		return -1;
	}
	printf("[%s:%d]客户端连接成功 newfd=%d\n",\
			inet_ntoa(cin.sin_addr), \
			ntohs(cin.sin_port), newfd);

	char buf[128] = "";
	ssize_t res = 0;

	while(1)
	{
		//清空字符串
		bzero(buf, sizeof(buf));
		//5、接收
		res = recv(newfd, buf, sizeof(buf), 0);
		if(res < 0)
		{
			ERR_MSG("recv");
			return -1;
		}
		else if(0 == res)
		{
			printf("[%s:%d]客户端下线 newfd=%d\n",\
			inet_ntoa(cin.sin_addr), \
			ntohs(cin.sin_port), newfd);

			break;
		}
		printf("[%s:%d] newfd=%d : %s\n",\
				inet_ntoa(cin.sin_addr), \
				ntohs(cin.sin_port), newfd, buf);

		//6、发送
		strcat(buf, "*_*");
		if(send(newfd, buf, strlen(buf), 0) < 0)
		{
			ERR_MSG("send");
			return -1;
		}
		printf("send success\n");

	}
	//7、关闭文件描述符
	if(close(newfd) < 0)
	{
		ERR_MSG("close");
		return -1;
	}
	if(close(sfd) < 0)
	{
		ERR_MSG("close");
		return -1;
	}
	return 0;
}

客户端的代码

#include 
#define PORT 4399 //端口号，范围1024~49151
#define IP "192.168.114.47"//本机IP ifconfig

int main(int argc, const char *argv[])
{
	//1、创建流式套接字
	int cfd = socket(AF_INET, SOCK_STREAM, 0);
	if(cfd < 0)
	{
		ERR_MSG("socket");
		return -1;
	}

	printf("socket creat success cfd=%d\n",cfd);
	//2、绑定客户端的地址信息-----非必须绑定
	//操作系统会自动给客户端绑定本机IP和随机端口

	//真实的地址信息结构体根据地址族指定 AF_INET :man 7 ip 
	struct sockaddr_in sin;

	sin.sin_family = AF_INET;

	sin.sin_port = htons(PORT);//服务器绑定的端口号
	sin.sin_addr.s_addr = inet_addr(IP);//服务器绑定的IP

	//3、连接服务器connect
	if(connect(cfd, (struct sockaddr*)&sin,sizeof(sin)) < 0)
	{
		ERR_MSG("connect");
		return -1;
	}
	printf("connect success\n");

	char buf[128] = "";
	ssize_t res = 0;

	while(1)
	{
		//清空字符串
		bzero(buf, sizeof(buf));
		printf("请输入>>> ");

		//4、发送
		fgets(buf, sizeof(buf), stdin);
		buf[strlen(buf)-1] = 0;

		if(send(cfd, buf, strlen(buf), 0) < 0)
		{
			ERR_MSG("send");
			return -1;
		}
		printf("send success\n");

		bzero(buf, sizeof(buf));
		//5、接收
		res = recv(cfd, buf, sizeof(buf), 0);
		if(res < 0)
		{
			ERR_MSG("recv");
			return -1;
		}
		else if(0 == res)
		{
			printf("服务器下线 cfd = %d\n", cfd);
			break;
		}
		printf("cfd = %d : %s\n", cfd, buf);
	}
	//6、关闭文件描述符
	if(close(cfd) < 0)
	{
		ERR_MSG("close");
		return -1;
	}
	return 0;
}

2. UDP服务器代码

#include 
#define PORT 4399 //端口号，范围1024~49151
#define IP "192.168.114.47"//本机IP ifconfig

int main(int argc, const char *argv[])
{
	//1、创建报式套接字
	int sfd = socket(AF_INET, SOCK_DGRAM, 0);
	if(sfd < 0)
	{
		ERR_MSG("socket");
		return -1;
	}

	printf("socket creat success sfd=%d\n",sfd);
	//填充服务器的地址信息结构体,
	//真实的地址信息结构体根据地址族指定，AF_INET
	struct sockaddr_in sin;
	sin.sin_family = AF_INET;
	sin.sin_port = htons(PORT);//端口号网络字节序1024-49151
	sin.sin_addr.s_addr = inet_addr(IP);//本机IP

	//绑定地址信息-----bind
	if(bind(sfd, (struct sockaddr*)&sin, sizeof(sin)) < 0)
	{
		ERR_MSG("bind");
		return -1;
	}
	printf("bind success\n");

	char buf[128]="";
	struct sockaddr_in cin;//存储发送方的地址信息
	socklen_t addrlen = sizeof(cin);

	while(1)
	{
		//接收数据
		bzero(buf,sizeof(buf));
		int res = recvfrom(sfd, buf, sizeof(buf), 0, (struct sockaddr*)&cin, &addrlen);
		
		if(0 == strcmp(buf,"quit"))
		{
			printf("[%s:%d]的客户端已下线\n",inet_ntoa(cin.sin_addr), ntohs(cin.sin_port));
		}
		if( res < 0)
		{
			ERR_MSG("recvfrom");
			return -1;
		}
		else if(0 == res)
		{
			printf("服务器已下线\n");
			break;
		}
		printf("[%s:%d] : %s\n",inet_ntoa(cin.sin_addr),ntohs(cin.sin_port),buf);
		//发送数据---->返还回去
		strcat(buf,"*_*");
		if(sendto(sfd, buf, sizeof(buf), 0, (struct sockaddr*)&cin, sizeof(cin)) < 0)
		{
			ERR_MSG("sendto");
			return -1;
		}

		printf("sendto success\n");
	}


	//关闭
	close(sfd);

	return 0;
}

UDP客户端代码

#include 
#define PORT 4399 //目标端口号，范围1024~49151
#define IP "192.168.114.47"//目标IP

int main(int argc, const char *argv[])
{
	//1、创建报式套接字
	int sfd = socket(AF_INET, SOCK_DGRAM, 0);
	if(sfd < 0)
	{
		ERR_MSG("socket");
		return -1;
	}

	printf("socket creat success sfd=%d\n",sfd);
	//填充服务器的地址信息结构体,
	//真实的地址信息结构体根据地址族指定，AF_INET
	struct sockaddr_in sin;
	sin.sin_family = AF_INET;
	sin.sin_port = htons(PORT);//目标的端口号网络字节序1024-49151
	sin.sin_addr.s_addr = inet_addr(IP);//目标IP

	//绑定地址信息-----bind(非必须绑定)
	
	char buf[128]="";
	socklen_t addrlen = sizeof(sin);

	while(1)
	{
		bzero(buf,sizeof(buf));
		printf("请输入>>> ");
		fgets(buf, sizeof(buf), stdin);
		buf[strlen(buf)-1] = '\0';
		//发送数据---->返还回去
		if(sendto(sfd, buf, sizeof(buf), 0, (struct sockaddr*)&sin, sizeof(sin)) < 0)
		{
			ERR_MSG("sendto");
			return -1;
		}

		if(strcmp(buf,"quit") == 0)
		{
			printf("客户端已下线\n");
			break;
		}
		printf("sendto success\n");

		bzero(buf,sizeof(buf));
		//接收数据
		int res = recvfrom(sfd, buf, sizeof(buf), 0, (struct sockaddr*)&sin, &addrlen);
		if(res < 0)
		{
			ERR_MSG("recvfrom");
			return -1;
		}
		else if(0 == res)
		{
			printf("服务器已下线\n");
			break;
		}

		printf("[%s:%d] : %s\n",inet_ntoa(sin.sin_addr),ntohs(sin.sin_port),buf);

		}


	//关闭
	close(sfd);

	return 0;
}