Re: [dhcwg] question about basic broadcast

Hi Ranganath,

this list is for protocol developement issues, not for programing questions. 
Please try another available lists.

By the way: The below C program will never compile, and if you use the right 
parameter in sendto() you'll have more success.
Here is the definition of sendto:

ssize_t sendto(int s, const void *msg, size_t len, int flags, const struct 
sockaddr *to, socklen_t tolen)

See:
http://www.freebsd.org/cgi/man.cgi?
query=sendto&apropos=0&sektion=0&manpath=FreeBSD+4.3-RELEASE&format=html

Zitiere Ranganath Sudarshan <tsranga@Stanford.EDU>:

> Hi,
> I was trying to get the following scenario to work:
> 
> On one machine on the LAN, you have a Java program listening on some
> port
> X for datagram packets coming in.
> 
> On another box, which is running FreeBSD and which does NOT have an IP
> address configured (pre-DHCP configuration), I want to have code which
> broadcasts a message to 255.255.255.255, port X, and I want the other
> box
> running Java to pick up this datagram packet.
> 
> int on = 1;
> char *msg = strdup("message");
> sockfd = socket(AF_INET, SOCK_DGRAM, 0);
> setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on));
> their_addr.sin_family = AF_INET;
> their_addr.sin_port = htons(MYPORT);
> their_addr.sin_addr.s_addr = inet_addr("255.255.255.255");
> memset(&(their_addr.sin_zero), '\0', 8);
> numbytes = sendto(sockfd, msg, strlen(msg), MSG_DONTROUTE);
> 
> numbytes is returned as -1 and the error: Network is Unreachable is
> returned.
> 
> Does anyone know what the problem may be?  My basic aim is to have the
> FreeBSD box without IP configured be able to communicate with my box
> running a Java Datagram listener.  I would greatly appreciate any help
> on
> this matter.  I realize that the problem is a subset of what DHCP
> enables
> one to do, but I wish to only have this simple functionality, and not
> all
> of the DHCP protocol.
> 
> Thanks,
> RTS
> 
> 
> 
> _______________________________________________
> dhcwg mailing list
> dhcwg@ietf.org
> http://www1.ietf.org/mailman/listinfo/dhcwg
> 
> 

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