static int umcast_open()

in drivers/umcast_user.c [64:146]

• 68 lines of code
• 14 McCabe index (conditional complexity)

static int umcast_open(void *data)
{
	struct umcast_data *pri = data;
	struct sockaddr_in *lsin = pri->listen_addr;
	struct sockaddr_in *rsin = pri->remote_addr;
	struct ip_mreq mreq;
	int fd, yes = 1, err = -EINVAL;


	if ((!pri->unicast && lsin->sin_addr.s_addr == 0) ||
	    (rsin->sin_addr.s_addr == 0) ||
	    (lsin->sin_port == 0) || (rsin->sin_port == 0))
		goto out;

	fd = socket(AF_INET, SOCK_DGRAM, 0);

	if (fd < 0) {
		err = -errno;
		printk(UM_KERN_ERR "umcast_open : data socket failed, "
		       "errno = %d\n", errno);
		goto out;
	}

	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
		err = -errno;
		printk(UM_KERN_ERR "umcast_open: SO_REUSEADDR failed, "
		       "errno = %d\n", errno);
		goto out_close;
	}

	if (!pri->unicast) {
		/* set ttl according to config */
		if (setsockopt(fd, SOL_IP, IP_MULTICAST_TTL, &pri->ttl,
			       sizeof(pri->ttl)) < 0) {
			err = -errno;
			printk(UM_KERN_ERR "umcast_open: IP_MULTICAST_TTL "
			       "failed, error = %d\n", errno);
			goto out_close;
		}

		/* set LOOP, so data does get fed back to local sockets */
		if (setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP,
			       &yes, sizeof(yes)) < 0) {
			err = -errno;
			printk(UM_KERN_ERR "umcast_open: IP_MULTICAST_LOOP "
			       "failed, error = %d\n", errno);
			goto out_close;
		}
	}

	/* bind socket to the address */
	if (bind(fd, (struct sockaddr *) lsin, sizeof(*lsin)) < 0) {
		err = -errno;
		printk(UM_KERN_ERR "umcast_open : data bind failed, "
		       "errno = %d\n", errno);
		goto out_close;
	}

	if (!pri->unicast) {
		/* subscribe to the multicast group */
		mreq.imr_multiaddr.s_addr = lsin->sin_addr.s_addr;
		mreq.imr_interface.s_addr = 0;
		if (setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP,
			       &mreq, sizeof(mreq)) < 0) {
			err = -errno;
			printk(UM_KERN_ERR "umcast_open: IP_ADD_MEMBERSHIP "
			       "failed, error = %d\n", errno);
			printk(UM_KERN_ERR "There appears not to be a "
			       "multicast-capable network interface on the "
			       "host.\n");
			printk(UM_KERN_ERR "eth0 should be configured in order "
			       "to use the multicast transport.\n");
			goto out_close;
		}
	}

	return fd;

 out_close:
	close(fd);
 out:
	return err;
}