Very Computer

I would like to doing a UDP broadcast via port 3000. For linux boxes with one
network
interface card everything works as expected. But if the box has two or more
cards, these are
ignored and the broadcast is further send only via the first interface. My code
is attached at the end.

Do I need some special to go over all interfaces available on a linux box ?

--
------------------------
Thanks in advance
Lars Gsmar

here is the code:

int    i = 1;
static DWORD   dwLocalAddr = 0;
static u_short PortStatus = 3000;
static int     UpSocket;
char   szBuffer[1024],
struct sockaddr_in addr;

#define StrUp "This is the broadcast message"

 addr.sin_port        = htons(PortStatus);
 addr.sin_family      = AF_INET;
 addr.sin_addr.s_addr = (DWORD) -1;

UpSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
setsockopt(UpSocket, SOL_SOCKET, SO_BROADCAST, (LPSTR)&i,sizeof(i));
bind(UpSocket, &addr, sizeof(addr));

if (sendto(UpSocket, StrUp, sizeof(StrUp) + 1, 0, (LPSOCKADDR)&addr,
sizeof(addr)) == -1)
    {
      Message("Broadcast failed!\n");
    }

that means there is no generic way for me to say "bind to all_interfaces"
without having to detect all available interfaces? hmm, not very comfortable,
but I guess I have to go the hard way. How do figure out how many nic's are
installed?

Thanks in advance
Lars

note: My programm is a port from windows and at the moment it takes to much work
to remove the "Windows'ish syntax" ;-)

Quote:> I believe that you must create one socket for each interface and bind it
> explicitly to different interfaces. You can either discover addresses of
> your interfaces and put them in addr.sin_addr.s_addr or use SO_BINDTODEVICE
> option of setsockopt.
> By the way, using so Windows'ish syntax in Linux program is not the right
> thing.

Quote:> hmm, not very
> comfortable, but I guess I have to go the hard way. How do figure out how
> many nic's are installed?