help with multicast read (broken?)
Sean McNeil
sean at mcneil.com
Sun Oct 10 15:56:00 PDT 2004
I just installed 5.3-B7 on an i386 machine. All went well, but I cannot
get it to read data from a multicast address. I wrote a program that
works just fine on both x86 and ppc linux platforms. It does the
following:
struct sockaddr_in address;
int reuse_addr = 1;
int fd, i;
char *stream = "224.1.1.1";
char *port = "1234";
char *buffer;
buffer = malloc (1500);
if (buffer == NULL)
{
fprintf(stderr, "Cannot allocate buffer space\n");
return -1;
}
memset((char *) &address, 0, sizeof(address));
address.sin_family = AF_INET;
address.sin_port = htons(atoi(port));
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
fprintf(stderr, "Cannot open socket for stream %s\n", stream);
return -1;
}
setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuse_addr,
sizeof(reuse_addr));
address.sin_addr.s_addr = inet_addr(stream);
if (bind(fd, (struct sockaddr *) &address, sizeof(address)) < 0) {
fprintf(stderr, "Cannot bind to stream %s\n", stream);
close(fd);
return -1;
}
if (IN_MULTICAST(address.sin_addr.s_addr)) {
struct ip_mreq mreq;
mreq.imr_multiaddr.s_addr = address.sin_addr.s_addr;
mreq.imr_interface.s_addr = htonl(INADDR_ANY);
if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
&mreq, sizeof(mreq)) < 0) {
fprintf(stderr, "Cannot join multicast for %s\n", stream);
close(fd);
return -1;
}
}
i = recvfrom(fd, buffer, 1500, 0, NULL, NULL);
recvfrom never returns. I've looked at my program with sockstat and it
has 224.1.1.1:1234 open for foreign address *:*. Anyone see a problem
here?
I've placed my complete program at
www.mcneil.com/~sean/freebsd/stream.c
you can compile simply as
cc -o stream stream.c
I would appreciate comments/suggestions. Again, works fine under
various cpus with Linux.
Sean
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: This is a digitally signed message part
Url : http://lists.freebsd.org/pipermail/freebsd-current/attachments/20041010/f979267e/attachment.bin
More information about the freebsd-current
mailing list