[ECOS] Cannot sendto multicast using FreeBSD stack

[Chad Handrich <chandric at weldtechcorp dot com>]

Hello,

I wrote about this problem previously, but still have not found a 
solution (see the subject "Problem with multicast using FreeBSD stack" 
from 11/29/07)

I have eCos configured with the FreeBSD stack.  Everything is working 
except a portion where I have to SEND multicast UDP packets using 
sendto().  In these instances, sendto() returns -1, and errno == 
EHOSTUNREACH.

Here is my test multicast code that is failing:

   struct in_addr interface_addr;

   // eth0 is configured to be 89.89.200.181
   inet_aton("89.89.200.181", &interface_addr);
   setsockopt(skt, IPPROTO_IP, IP_MULTICAST_IF, &interface_addr, 
sizeof(interface_addr));
    
   struct in_addr multi_iface;
   getsockopt(skt, IPPROTO_IP, IP_MULTICAST_IF, &multi_iface, 
sizeof(multi_iface));
   diag_printf("getsockopt specifies %s as multicast interface\n", 
inet_ntoa(multi_iface));
   // This outputs the string:     getsockopt specifies 89.89.200.181 
as multicast interface

   // Sample data to send via multicast
   char buf[5]; buf[0] = 0; buf[1] = 1; buf[2] = 2; buf[3] = 3; buf[4] = 4;
  
   struct sockaddr_in to;
   to.sin_family = AF_INET;
   to.sin_port = htons(2222);
   inet_aton("239.192.23.160", &(to.sin_addr));
  
   int retval = sendto(skt, buf, 5, 0, (struct sockaddr *)&to, sizeof(to));
   diag_printf("post-sendto: errno=%d   retval=%d\n", errno, retval);
   // This outputs the string:     post-sendto: errno=365   retval=-1
   //  errno=365 corresponds to EHOSTUNREACH


Any help to get this multicast sendto() to succeed would be greatly 
appreciated.

My thanks,

Chad Handrich



  

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