多播收不到数据

发布于 2019-03-23 11:20:37 浏览：1094 订阅该版

```<div class="blockcode"><blockquote>void udpclient(int argc, char **argv)
{
int myFd, clientFd;
struct sockaddr_in myAddr, clientAddr;
struct ip_mreq mreq;
int addrlen = sizeof(clientAddr);
char buf[MAXBUF];
char addrTemp[INET_ADDRSTRLEN];

int db_Value=0;

int i,fd_pipe_w;

rt_memset(&myAddr, 0,sizeof(myAddr));
rt_memset(&clientAddr, 0,sizeof(clientAddr));
//创建套接字,datagrams
if((myFd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 
{

}

//设置本地地址端口信息
myAddr.sin_family = AF_INET;
myAddr.sin_addr.s_addr = INADDR_ANY;
if (argc == 3) {
myAddr.sin_port = htons(atoi(argv[2]));
} else {
myAddr.sin_port = htons(PORT);
}

//绑定本地套接字
if(bind(myFd, (struct sockaddr *)&myAddr, sizeof(myAddr)) != 0) {

}

//设置IP_MULTICAST_LOOP 
unsigned char loop = 1;
if (setsockopt(myFd, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)) != 0) {

return ;
}

//设置IP_MULTICAST_TTL 为1,即该多播最多只能经过一个路由器
unsigned char ttl = 1;
if (setsockopt(myFd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) != 0) {

return ;
}

//对struct ip_mreq这个结构体赋值
if (argc > 1) { //设置IP地址
int res;
if ((res = inet_pton(AF_INET, argv[1], &mreq.imr_multiaddr)) == -1) {

exit(errno);
} else if(res == 0) {
rt_kprintf("IP地址无效 ");
rt_kprintf("请输入一个多播地址:224.0.0.1 ~ 239.255.255.255 ");
return ;
} 
} else {
rt_kprintf("Usage:%s 多播地址(224.0.0.1 ~ 239.255.255.255) ", argv[0]);
return ;
}
mreq.imr_interface.s_addr = INADDR_ANY;
//将本机加入多播组中
if (setsockopt (myFd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) != 0) {

exit(errno);
}

rt_kprintf("Multicast is starting,waitting for information of Multicast..... ");
while (1)
{
rt_memset(buf, 0,sizeof(buf));
rt_kprintf("wait UDP data ");
if (recvfrom(myFd, buf, sizeof(buf) - 1, 0, (struct sockaddr *)&clientAddr, &addrlen) == -1) 
{

return ;
}
rt_kprintf("....... ");
/* 线程休眠一段时间 */
rt_thread_delay(50);
}
//退出广播组
if (setsockopt (myFd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) != 0) {

exit(errno);
}

return;
}
```
[table=98%]
[tr][td=760][align=center]1、硬件：正点原子阿波罗F429
2、想实现接受来自239.255.255.1 的多播数据，程序在linux可用，但是移植到到RT-Thread调试了很久都没有结果，希望有大兄弟能指点一下迷津。如果有大兄弟有RT-Thread的多播接收代码，有偿使用。[/td][/tr]
[/table]