int dn_dev_ioctl(unsigned int cmd, void __user *arg)
{
	char buffer[DN_IFREQ_SIZE];
	struct ifreq *ifr = (struct ifreq *)buffer;
	struct sockaddr_dn *sdn = (struct sockaddr_dn *)&ifr->ifr_addr;
	struct dn_dev *dn_db;
	struct net_device *dev;
	struct dn_ifaddr *ifa = NULL;
	struct dn_ifaddr __rcu **ifap = NULL;
	int ret = 0;

	if (copy_from_user(ifr, arg, DN_IFREQ_SIZE))
		return -EFAULT;
	ifr->ifr_name[IFNAMSIZ-1] = 0;

	dev_load(&init_net, ifr->ifr_name);

	switch (cmd) {
	case SIOCGIFADDR:
		break;
	case SIOCSIFADDR:
		if (!capable(CAP_NET_ADMIN))
			return -EACCES;
		if (sdn->sdn_family != AF_DECnet)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	rtnl_lock();

	if ((dev = __dev_get_by_name(&init_net, ifr->ifr_name)) == NULL) {
		ret = -ENODEV;
		goto done;
	}

	if ((dn_db = rtnl_dereference(dev->dn_ptr)) != NULL) {
		for (ifap = &dn_db->ifa_list;
		     (ifa = rtnl_dereference(*ifap)) != NULL;
		     ifap = &ifa->ifa_next)
			if (strcmp(ifr->ifr_name, ifa->ifa_label) == 0)
				break;
	}

	if (ifa == NULL && cmd != SIOCSIFADDR) {
		ret = -EADDRNOTAVAIL;
		goto done;
	}

	switch (cmd) {
	case SIOCGIFADDR:
		*((__le16 *)sdn->sdn_nodeaddr) = ifa->ifa_local;
		goto rarok;

	case SIOCSIFADDR:
		if (!ifa) {
			if ((ifa = dn_dev_alloc_ifa()) == NULL) {
				ret = -ENOBUFS;
				break;
			}
			memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
		} else {
			if (ifa->ifa_local == dn_saddr2dn(sdn))
				break;
			dn_dev_del_ifa(dn_db, ifap, 0);
		}

		ifa->ifa_local = ifa->ifa_address = dn_saddr2dn(sdn);

		ret = dn_dev_set_ifa(dev, ifa);
	}
done:
	rtnl_unlock();

	return ret;
rarok:
	if (copy_to_user(arg, ifr, DN_IFREQ_SIZE))
		ret = -EFAULT;
	goto done;
}
int dn_dev_ioctl(unsigned int cmd, void __user *arg)
{
	char buffer[DN_IFREQ_SIZE];
	struct ifreq *ifr = (struct ifreq *)buffer;
	struct sockaddr_dn *sdn = (struct sockaddr_dn *)&ifr->ifr_addr;
	struct dn_dev *dn_db;
	struct net_device *dev;
	struct dn_ifaddr *ifa = NULL;
	struct dn_ifaddr __rcu **ifap = NULL;
	int ret = 0;

	if (copy_from_user(ifr, arg, DN_IFREQ_SIZE))
		return -EFAULT;
	ifr->ifr_name[IFNAMSIZ-1] = 0;

	dev_load(&init_net, ifr->ifr_name);

	switch (cmd) {
	case SIOCGIFADDR:
		break;
	case SIOCSIFADDR:
		if (!capable(CAP_NET_ADMIN))
			return -EACCES;
		if (sdn->sdn_family != AF_DECnet)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	rtnl_lock();

	if ((dev = __dev_get_by_name(&init_net, ifr->ifr_name)) == NULL) {
		ret = -ENODEV;
		goto done;
	}

	if ((dn_db = rtnl_dereference(dev->dn_ptr)) != NULL) {
		for (ifap = &dn_db->ifa_list;
		     (ifa = rtnl_dereference(*ifap)) != NULL;
		     ifap = &ifa->ifa_next)
			if (strcmp(ifr->ifr_name, ifa->ifa_label) == 0)
				break;
	}

	if (ifa == NULL && cmd != SIOCSIFADDR) {
		ret = -EADDRNOTAVAIL;
		goto done;
	}

	switch (cmd) {
	case SIOCGIFADDR:
		*((__le16 *)sdn->sdn_nodeaddr) = ifa->ifa_local;
		goto rarok;

	case SIOCSIFADDR:
		if (!ifa) {
			if ((ifa = dn_dev_alloc_ifa()) == NULL) {
				ret = -ENOBUFS;
				break;
			}
			memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
		} else {
			if (ifa->ifa_local == dn_saddr2dn(sdn))
				break;
			dn_dev_del_ifa(dn_db, ifap, 0);
		}

		ifa->ifa_local = ifa->ifa_address = dn_saddr2dn(sdn);

		ret = dn_dev_set_ifa(dev, ifa);
	}
done:
	rtnl_unlock();

	return ret;
rarok:
	if (copy_to_user(arg, ifr, DN_IFREQ_SIZE))
		ret = -EFAULT;
	goto done;
}