Linux系统下UDP发送和接收广播消息小例子

// 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] view
plaincopy

// 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。。