网络编程07-实现UDP转发

udp_client.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
	   
#define SERVER_IP	"172.17.15.227" //服务器IP
#define SERVER_PORT	60000

#define OTHER_IP	"192.168.11.91" //其他人的IP
#define OTHER_PORT	60001

struct send_info
{
	char buf[1024];
	struct sockaddr_in other_addr; //其它人的地址
};

//接收其他人发来的消息
void *recv_buf(void *arg)
{
	pthread_detach(pthread_self());
	int socket_fd = *(int *)arg;
	
	int ret;
	struct sockaddr_in recv_addr;
	socklen_t address_len = sizeof(recv_addr);	

	while(1)
	{		
		struct send_info recv_info;	
		memset(&recv_info,0,sizeof(recv_info));
	
		ret = recvfrom(socket_fd,&recv_info,sizeof(recv_info),0,(struct sockaddr *)&recv_addr,&address_len);

		//打印接受的客户端的信息
		char *ip = inet_ntoa(recv_addr.sin_addr);
		int port = ntohs(recv_addr.sin_port);
		//printf("接收到的信息[ip:%s port:%d]buf:%s ret:%d\n",ip,port,recv_info.buf,ret);	
		printf("接收到的信息buf:%s ret:%d\n",recv_info.buf,ret);	
	}	
}

int main(int argc,char **argv)
{
	if(argc != 3)
	{
		printf("请输入发送给他人的IP地址和端口<ip><port>\n");//键盘输入你要发送的ip和端口号
		return -1;
	}

	int ret;
	//创建套接字
	int socket_fd;
	//ipv4:AF_INET UDP协议:SOCK_DGRAM
	socket_fd = socket(AF_INET,SOCK_DGRAM,0);
	if(socket_fd < 0)
	{
		perror("socket fail");
		return -1;
	}
	
	pthread_t tid;
	ret = pthread_create(&tid,NULL,recv_buf,&socket_fd);
	if(ret != 0)
	{
		perror("pthread_create fail");
		return -1;		
	}
	
	//填充服务器的IP地址
	struct sockaddr_in server_addr;
	server_addr.sin_family = AF_INET;//地址族
	server_addr.sin_port = htons(SERVER_PORT);//将本机端口转换为网络端口
	server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);//将本机IP转换为网络IP
	//socklen_t dest_len = sizeof(server_addr);
	
	//直接给UDP的服务器发送数据	
	while(1)
	{	
		//printf("请输入发送的信息:");
		struct send_info info;
		scanf("%s",info.buf);//输入的信息
		info.other_addr.sin_family = AF_INET;
		// info.other_addr.sin_port = htons(OTHER_PORT);//其他人的端口
		// info.other_addr.sin_addr.s_addr = inet_addr(OTHER_IP);//其他人的IP
		info.other_addr.sin_port = htons(atoi(argv[2]));//键盘输入端口
		info.other_addr.sin_addr.s_addr = inet_addr(argv[1]);//键盘输入IP	
		
		//给服务器发送数据
		ret = sendto(socket_fd,&info,sizeof(struct send_info),0,(struct sockaddr *)&server_addr,sizeof(server_addr));
		printf("send success ret:%d\n",ret);	
	}
	
	//关闭套接字
	close(socket_fd);
	
	return 0;
}

udp_server.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
	   
#define SERVER_IP	"172.17.15.227" //服务器IP
#define SERVER_PORT	60000
#define OTHER_IP "172.17.15.227"
#define OTHER_PORT 60008

struct send_info
{
	char buf[1024];
	struct sockaddr_in other_addr; //其它人的地址
};

int main(int argc,char **argv)
{
	int ret;
	int socket_fd;
	//udp协议：SOCK_DGRAM
	socket_fd = socket(AF_INET,SOCK_DGRAM,0);
	if(socket_fd < 0)
	{
		perror("socket fail");
		return -1;
	}
	
	//填充服务器的IP地址
	struct sockaddr_in server_addr;
	server_addr.sin_family = AF_INET;//地址族
	server_addr.sin_port = htons(SERVER_PORT);//将本机端口转换为网络端口
	server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);//将本机IP转换为网络IP
	socklen_t addrlen = sizeof(server_addr);
	
	//绑定本机IP
	ret = bind(socket_fd,(struct sockaddr *)&server_addr,addrlen);
	if(ret < 0)
	{
		perror("bind fail");
		return -1;
	}
	printf("bind success\n");
	
	//新建一个用来接受客户端的地址
	struct sockaddr_in client_addr;
	socklen_t address_len = sizeof(client_addr);
	char *ip = NULL;
	int port = 0;
	struct send_info recv_info;
	

	while(1)
	{	
		//接收客户端数据
		memset(&recv_info,0,sizeof(recv_info));
		ret = recvfrom(socket_fd,&recv_info,sizeof(recv_info),0,(struct sockaddr *)&client_addr,&address_len);
		if(ret < 0)
		{
			perror("client down");
			return -1;
		}
		
		//打印接受的客户端的信息
		ip = inet_ntoa(client_addr.sin_addr);
		port = ntohs(client_addr.sin_port);
		printf("[ip:%s port:%d]buf:%s ret:%d\n",ip,port,recv_info.buf,ret);
		
		//解析recv_info里面的其他人的地址和端口
		ip = inet_ntoa(recv_info.other_addr.sin_addr);
		port = ntohs(recv_info.other_addr.sin_port);
		if( port == 0)
		{
			recv_info.other_addr.sin_port = htons(OTHER_PORT);//将本机端口转换为网络端口
			recv_info.other_addr.sin_addr.s_addr = inet_addr(OTHER_IP);//将本机IP转换为网络IP
			
			ip = inet_ntoa(recv_info.other_addr.sin_addr);
			port = ntohs(recv_info.other_addr.sin_port);
			
			printf("[other_addr ip:%s port:%d buf:%s]\n",ip,port,recv_info.buf);
			printf("-------------------------------------------------------\n");
			struct sockaddr_in recv_addr = recv_info.other_addr; //其他人的地址


			//将客户端的的数据转发给其他人的地址和端口号
			sendto(socket_fd,recv_info.buf,strlen(recv_info.buf),0,(struct sockaddr *)&recv_addr,sizeof(recv_addr));
		}
		else
		{
			printf("[other_addr ip:%s port:%d buf:%s]\n",ip,port,recv_info.buf);
			printf("-------------------------------------------------------\n");
			struct sockaddr_in recv_addr = recv_info.other_addr; //其他人的地址


			//将客户端的的数据转发给其他人的地址和端口号
			sendto(socket_fd,recv_info.buf,strlen(recv_info.buf),0,(struct sockaddr *)&recv_addr,sizeof(recv_addr));
		}
		
	}
	
	//关闭套接字
	close(socket_fd);
	return 0;
}

gcc.sh

#!/bin/bash

gcc 1_udp_client_转发.c -o client -lpthread
arm-linux-gcc 1_udp_client_转发.c -o client_arm -lpthread
gcc 2_udp_server_转发.c -o server