On Wed, Jan 04, 2012 at 04:28:46PM +0000, Wolfgang wrote:

Hi,

OK, I create 1 socket for one source address (what is the maximum of pgns per 
socket?). 

a bit unlimited, use filters there.

So if I use recvfrom for one specific pgn - while waiting for that specific pgn

Nope,
man recvfrom ....

can-j1939 will store the source address & PGN into the 'src_addr' (called dest_addr
in your example).
You cannot pick a specific PGN from the incoming queue.

the other pgns from that src address are stored in the buffer of the socket and
will be later "recvfrom"? So no can frame will be lost?

Am I right, with this, only the j1939 frame with id<0x19233000> should be
received, but nothing is done, (just waiting for anything), what have I done 
wrong?

#include <sys/ioctl.h>
#include <net/if.h>
#include <string.h>
#include <linux/can/j1939.h>
#include <linux/can.h>
#include <unistd.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/types.h>



int main (void)
{
	int s;
	s = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
	    
	struct sockaddr_can addr;

    memset(&addr, 0, sizeof(addr));
    addr.can_ifindex = if_nametoindex("can0");
    addr.can_addr.j1939.name = J1939_NO_NAME;    
    addr.can_addr.j1939.addr = 0x00;
    addr.can_addr.j1939.pgn = J1939_NO_PGN;
    addr.can_family = AF_CAN;  
   
   
    if (bind(s, (void *)&addr, sizeof(addr))<0)
    	{
    		perror ("bind failed");
        	}
   
   
	struct can_frame frame      	

you should do now:
	int ret;
	socklen_t len; 
	struct sockaddr_can src_addr;
	char buf[128];

	while (1) {
		len = sizeof(src_addr);
		ret = recvfrom(s, buf, sizeof(buf), 0, (void *)&src_addr, &len);
		if (ret < 0)
			perror ("recvfrom failed");
		/* now, ret contains the received size */ 
		/* do things with data */
		/* set broadcast */
		src_addr.can_addr.j1939.addr = J1939_NO_ADDR;
		src_addr.can_addr.j1939.name = J1939_NO_NAME;
		if (sendto(s2, buf, ret, 0, (void *)&src_addr, len) < 0)
			perror("sendto failed");
	}

   
   struct sockaddr_can dest_addr;
   
   memset(&dest_addr, 0, sizeof(dest_addr));
   dest_addr.can_family = AF_CAN;
   dest_addr.can_addr.j1939.name = J1939_NO_NAME;
   dest_addr.can_addr.j1939.addr = 0x30;
   dest_addr.can_addr.j1939.pgn = 0x12300;
   
    	if (recvfrom(s, frame.data, sizeof(frame.data), 0, (void *)&dest_addr,\
 sizeof(dest_addr))<0)
		{
  	 	perror ("recvfrom failed");
  	 	}
   		 
  return 0;
}


Wolfgang



--
To unsubscribe from this list: send the line "unsubscribe linux-can" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html