Linux系统下UDP发送和接收广播消息小例子

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网络通信 2013-01-07 10:54
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[cpp]
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// 发送端
#include <iostream>
#include <stdio.h>

#include <sys/socket.h>
#include <unistd.h>

#include <sys/types.h>
#include <netdb.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <string.h>


using namespace std;

int main()
{
setvbuf(stdout, NULL, _IONBF, 0);
fflush(stdout);

int sock = -1;
if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
{
cout<<"socket error"<<endl;
return false;
}

const int opt = 1;
//设置该套接字为广播类型，
int nb = 0;
nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));
if(nb == -1)
{
cout<<"set socket error..."<<endl;
return false;
}

struct sockaddr_in addrto;
bzero(&addrto, sizeof(struct sockaddr_in));
addrto.sin_family=AF_INET;
addrto.sin_addr.s_addr=htonl(INADDR_BROADCAST);
addrto.sin_port=htons(6000);
int nlen=sizeof(addrto);

while(1)
{
sleep(1);
//从广播地址发送消息
char smsg[] = {"abcdef"};
int ret=sendto(sock, smsg, strlen(smsg), 0, (sockaddr*)&addrto, nlen);
if(ret<0)
{
cout<<"send error...."<<ret<<endl;
}
else
{
printf("ok ");
}
}

return 0;
}

// 发送端
#include <iostream>
#include <stdio.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/types.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>

using namespace std;

int main()
{
	setvbuf(stdout, NULL, _IONBF, 0); 
	fflush(stdout); 

	int sock = -1;
	if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 
	{   
		cout<<"socket error"<<endl;	
		return false;
	}   
	
	const int opt = 1;
	//设置该套接字为广播类型，
	int nb = 0;
	nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));
	if(nb == -1)
	{
		cout<<"set socket error..."<<endl;
		return false;
	}

	struct sockaddr_in addrto;
	bzero(&addrto, sizeof(struct sockaddr_in));
	addrto.sin_family=AF_INET;
	addrto.sin_addr.s_addr=htonl(INADDR_BROADCAST);
	addrto.sin_port=htons(6000);
	int nlen=sizeof(addrto);

	while(1)
	{
		sleep(1);
		//从广播地址发送消息
		char smsg[] = {"abcdef"};
		int ret=sendto(sock, smsg, strlen(smsg), 0, (sockaddr*)&addrto, nlen);
		if(ret<0)
		{
			cout<<"send error...."<<ret<<endl;
		}
		else
		{		
			printf("ok ");	
		}
	}

	return 0;
}

[cpp]
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// 接收端 http://blog.csdn.net/robertkun

#include <iostream>

#include <stdio.h>
#include <sys/socket.h>

#include <unistd.h>
#include <sys/types.h>

#include <netdb.h>
#include <netinet/in.h>

#include <arpa/inet.h>
#include <string.h>



using namespace std;

int main()
{
setvbuf(stdout, NULL, _IONBF, 0);
fflush(stdout);

// 绑定地址
struct sockaddr_in addrto;
bzero(&addrto, sizeof(struct sockaddr_in));
addrto.sin_family = AF_INET;
addrto.sin_addr.s_addr = htonl(INADDR_ANY);
addrto.sin_port = htons(6000);

// 广播地址
struct sockaddr_in from;
bzero(&from, sizeof(struct sockaddr_in));
from.sin_family = AF_INET;
from.sin_addr.s_addr = htonl(INADDR_ANY);
from.sin_port = htons(6000);

int sock = -1;
if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
{
cout<<"socket error"<<endl;
return false;
}

const int opt = 1;
//设置该套接字为广播类型，
int nb = 0;
nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));
if(nb == -1)
{
cout<<"set socket error..."<<endl;
return false;
}

if(bind(sock,(struct sockaddr *)&(addrto), sizeof(struct sockaddr_in)) == -1)
{
cout<<"bind error..."<<endl;
return false;
}

int len = sizeof(sockaddr_in);
char smsg[100] = {0};

while(1)
{
//从广播地址接受消息
int ret=recvfrom(sock, smsg, 100, 0, (struct sockaddr*)&from,(socklen_t*)&len);
if(ret<=0)
{
cout<<"read error...."<<sock<<endl;
}
else
{
printf("%s\t", smsg);
}

sleep(1);
}

return 0;
}

// 接收端 http://blog.csdn.net/robertkun 
#include <iostream>
#include <stdio.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/types.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>

using namespace std;

int main()
{
	setvbuf(stdout, NULL, _IONBF, 0); 
	fflush(stdout); 

	// 绑定地址
	struct sockaddr_in addrto;
	bzero(&addrto, sizeof(struct sockaddr_in));
	addrto.sin_family = AF_INET;
	addrto.sin_addr.s_addr = htonl(INADDR_ANY);
	addrto.sin_port = htons(6000);
	
	// 广播地址
	struct sockaddr_in from;
	bzero(&from, sizeof(struct sockaddr_in));
	from.sin_family = AF_INET;
	from.sin_addr.s_addr = htonl(INADDR_ANY);
	from.sin_port = htons(6000);
	
	int sock = -1;
	if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 
	{   
		cout<<"socket error"<<endl;	
		return false;
	}   

	const int opt = 1;
	//设置该套接字为广播类型，
	int nb = 0;
	nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));
	if(nb == -1)
	{
		cout<<"set socket error..."<<endl;
		return false;
	}

	if(bind(sock,(struct sockaddr *)&(addrto), sizeof(struct sockaddr_in)) == -1) 
	{   
		cout<<"bind error..."<<endl;
		return false;
	}

	int len = sizeof(sockaddr_in);
	char smsg[100] = {0};

	while(1)
	{
		//从广播地址接受消息
		int ret=recvfrom(sock, smsg, 100, 0, (struct sockaddr*)&from,(socklen_t*)&len);
		if(ret<=0)
		{
			cout<<"read error...."<<sock<<endl;
		}
		else
		{		
			printf("%s\t", smsg);	
		}

		sleep(1);
	}

	return 0;
}

自已在Linux虚拟机下测试可以成功, 前提是要把主机设置在同一网段内, 还有就是不要忘记关闭Linux的防火墙.. 可以使用setup命令进行设置。

(我在测试的时候只能发送不收接收，折磨了我半天，后来才想到是Linux防火墙的问题。。)



关于虚拟机的网卡配置，建议选择桥接模式。NAT的模式的话，是受限制的，可能会收不到广播消息。

具体的参考网上的文章吧。。

祝你成功。。