Ask question,my NDK server on DM642 can't receive broadcast message from PC ......

Rong Zeng

Prodigy 55 points

Hello everyone,

I try to receive broadcast message from client on PC to DM642,but it doesn't work

who can help me ?

DM642 is server ,to receive message.while PC is client,to send broadcast message

the IP on DM642 is 192.168.1.77,mask is 255.255.255.0,Gateway IP is 192.168.1.1,the port is 7000.

the PC calls to 192.168.1.255,port is 7000.

there is my piece of code:

void tskServer()

{

	int broadsock;
	struct sockaddr_in broadClient,broadaddr;
	int len = sizeof(struct sockaddr_in);
	char buf[100];
	int so_broadcast=1;

	struct timeval timeout={10,0};

   	fdOpenSession(TaskSelf()); 
   		
	bzero( &broadaddr, sizeof(struct sockaddr_in) );
	broadaddr.sin_addr.s_addr = inet_addr("192.168.1.77");
	broadaddr.sin_family = AF_INET;
	broadaddr.sin_port = htons(7000);                  
	broadaddr.sin_len  = sizeof(broadaddr);

        broadsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

     setsockopt(broadsock,SOL_SOCKET,SO_RCVTIMEO,&timeout,sizeof(timeout));

         setsockopt(broadsock,SOL_SOCKET,SO_BROADCAST,&so_broadcast,sizeof(int));

 setsockopt(broadsock,SOL_SOCKET,SO_IFDEVICE,(void *)&so_broadcast,sizeof(int));

 bind(broadsock,&broadaddr,len);

       recvfrom(broadsock,(void *)buf,100,MSG_WAITALL,(PSA)&broadClient,&len);

	fdCloseSession(TaskSelf());
    	TaskBlock(TaskSelf());

 exit(1);

over 13 years ago

0 npb17 over 13 years ago

Expert 1615 points

I had a similar issue with the C6472 DSP. Depending on which NDK you are using, see this post:

http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/439/t/122182.aspx?PageIndex=3

If that link doesn't work, the post is titled "NDK RX Filter". I marked the fix as the verified answer.

Nick

0 Rong Zeng over 13 years ago in reply to npb17

Prodigy 55 points

Nick:

Thanks for your reply,but I don't catch your point.

Is there anything wrong with my NDK configuration ?

I tried to bind NULL ip address(INADDR_ANY) with the socket, it seems better,

but I don't know why it can receive message with the socket that has no ip address?

0 npb17 over 13 years ago in reply to Rong Zeng

Expert 1615 points

Is your device able to receive directed UDP packets to IP 192.168.1.77 but not broadcast packets sent to 255.255.255.255? If so, then the problem might be the same as mine. I had to recompile the NDK stack.lib with the change mentioned in the referenced post, then rebuild my project. That seemed to fix receiving broadcast packets for me, as long as they were sent to the correct port number that the device was listening on.

I have been using a similar NDK configuration to yours. One difference is my bind() is in a while-loop. Also, your recvfrom() call should probably be in a loop. I believe it will timeout in 10 seconds even though you are using MSG_WAITALL since you set the SO_RCVTIMEO option. My configuration is below as a reference:

   SOCKET          s = INVALID_SOCKET;
   struct sockaddr_in              sin;
   struct timeval                  timeout;
   char                                *pBuf;
   HANDLE                          hBuffer;

   int           tmp;
   int           cnt;
   int           val;
   Int            status;

    s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

   // setup for broadcast transmits
   val = 1;
   tmp = setsockopt( s, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
   tmp = setsockopt( s, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
   tmp = setsockopt( s, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));

   // initialize the addresses we are receiving at
   bzero(&sin, sizeof(struct sockaddr_in));
   sin.sin_family       = AF_INET;
   sin.sin_len          = sizeof(sin);
   sin.sin_addr.s_addr = inet_addr("192.168.1.77");
   sin.sin_port         = htons(7000);

   // bind to known address/port
   while ( bind(s, (PSA)&sin, sizeof(sin)) < 0);

   // Configure our socket timeout to be 10 ms
   timeout.tv_sec = 0;
   timeout.tv_usec = 10000;
   tmp = setsockopt( s, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof( timeout ) );
   tmp = setsockopt( s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof( timeout ) );

while(1)
   {

   /* ----------------------------------------------------------------------
* Receive message over ethernet
   * ---------------------------------------------------------------------*/
   cnt = 0;
   tmp = sizeof(sin);
   cnt = recvncfrom(s, (void**)&pBuf, MSG_WAITALL,(PSA)&sin, &tmp,&hBuffer); //receive with no copy
   if (cnt > 0)
   {

// Do stuff with message

} // end if

}// end while(1)

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Ask question,my NDK server on DM642 can't receive broadcast message from PC ......