UDP实现网络数据传输

客户端代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>


int main(int arg, char *args[])
{
	if (arg < 3)
	{
		return -1;
	}


	int st = socket(AF_INET, SOCK_DGRAM, 0);//建立socket的时候第二个参数值为SOCK_DGRAM
	if (st == -1)
	{
		printf("socket failed %s\n", strerror(errno));
		return 0;
	}

	int port = atoi(args[2]);

	int on = 1;
	if (setsockopt(st, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) == -1)//设置UDP socket可以发送广播消息
	{
		printf("setsockopt failed %s\n", strerror(errno));
		return EXIT_FAILURE;
	}


	struct sockaddr_in addr; // 定义一个IP地址的结构
	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;// 设置结构地址类型为TCP/IP地址
	addr.sin_port = htons(port); // 制定一个端口号：8080，htons：将short类型从host字节类型转到net字节类型
	addr.sin_addr.s_addr = inet_addr(args[1]);

	char buf[1024];
	while (1)
	{
		memset(buf, 0, sizeof(buf));
		read(STDIN_FILENO, buf, sizeof(buf));	//读取用户键盘输入
		if (sendto(st, buf, strlen(buf), 0, (struct sockaddr *) &addr,
				sizeof(addr)) == -1)	//udp使用sendto发送消息
		{
			printf("sendto failed %s\n", strerror(errno));
			break;
		}
	}
	close(st);
	return EXIT_SUCCESS;
}

服务端代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>

int main(int arg, char *args[])
{
	if (arg < 2)
	{
		return -1;
	}
	int port = atoi(args[1]);
	int st = socket(AF_INET, SOCK_DGRAM, 0); //初始化socket
	if (st == -1)
	{
		printf("socket failed %s\n", strerror(errno));
		return 0;
	}

	struct sockaddr_in addr; // 定义一个IP地址结构
	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET; // 将addr结构的属性定位为TCP/IP地址
	addr.sin_port = htons(port); // 将本地字节顺序转化为网络字节顺序
	addr.sin_addr.s_addr = htonl(INADDR_ANY); // INADDR_ANY代表这个server上所有的地址

	// 将ip与server程序绑定
	if (bind(st, (struct sockaddr *) &addr, sizeof(addr)) == -1)
	{
		printf("bind failed %s\n", strerror(errno));
		return EXIT_FAILURE;
	}

	char buf[1024];
	struct sockaddr_in client_addr;
	socklen_t len = sizeof(client_addr);
	while(1)
	{
		memset(&client_addr, 0, sizeof(client_addr));
		memset(buf, 0, sizeof(buf));
		if(recvfrom(st, buf, sizeof(buf), 0,
				(struct sockaddr *)&client_addr, &len) == -1)
		{
			printf("recvfrom failed %s\n", strerror(errno));
			break;
		}else
		{

			printf("%s recv is %s\n", inet_ntoa(client_addr.sin_addr), buf);
		}
	}
	close(st);
	return EXIT_SUCCESS;
}