tun.c

来自「linux 内核源代码」· C语言 代码 · 共 913 行 · 第 1/2 页

		    return tun;
	}

	return NULL;
}

static int tun_set_iff(struct file *file, struct ifreq *ifr)
{
	struct tun_struct *tun;
	struct net_device *dev;
	int err;

	tun = tun_get_by_name(ifr->ifr_name);
	if (tun) {
		if (tun->attached)
			return -EBUSY;

		/* Check permissions */
		if (((tun->owner != -1 &&
		      current->euid != tun->owner) ||
		     (tun->group != -1 &&
		      current->egid != tun->group)) &&
		     !capable(CAP_NET_ADMIN))
			return -EPERM;
	}
	else if (__dev_get_by_name(&init_net, ifr->ifr_name))
		return -EINVAL;
	else {
		char *name;
		unsigned long flags = 0;

		err = -EINVAL;

		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		/* Set dev type */
		if (ifr->ifr_flags & IFF_TUN) {
			/* TUN device */
			flags |= TUN_TUN_DEV;
			name = "tun%d";
		} else if (ifr->ifr_flags & IFF_TAP) {
			/* TAP device */
			flags |= TUN_TAP_DEV;
			name = "tap%d";
		} else
			goto failed;

		if (*ifr->ifr_name)
			name = ifr->ifr_name;

		dev = alloc_netdev(sizeof(struct tun_struct), name,
				   tun_setup);
		if (!dev)
			return -ENOMEM;

		tun = netdev_priv(dev);
		tun->dev = dev;
		tun->flags = flags;
		/* Be promiscuous by default to maintain previous behaviour. */
		tun->if_flags = IFF_PROMISC;
		/* Generate random Ethernet address. */
		*(u16 *)tun->dev_addr = htons(0x00FF);
		get_random_bytes(tun->dev_addr + sizeof(u16), 4);
		memset(tun->chr_filter, 0, sizeof tun->chr_filter);

		tun_net_init(dev);

		if (strchr(dev->name, '%')) {
			err = dev_alloc_name(dev, dev->name);
			if (err < 0)
				goto err_free_dev;
		}

		err = register_netdevice(tun->dev);
		if (err < 0)
			goto err_free_dev;

		list_add(&tun->list, &tun_dev_list);
	}

	DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);

	if (ifr->ifr_flags & IFF_NO_PI)
		tun->flags |= TUN_NO_PI;

	if (ifr->ifr_flags & IFF_ONE_QUEUE)
		tun->flags |= TUN_ONE_QUEUE;

	file->private_data = tun;
	tun->attached = 1;

	strcpy(ifr->ifr_name, tun->dev->name);
	return 0;

 err_free_dev:
	free_netdev(dev);
 failed:
	return err;
}

static int tun_chr_ioctl(struct inode *inode, struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	struct tun_struct *tun = file->private_data;
	void __user* argp = (void __user*)arg;
	struct ifreq ifr;
	DECLARE_MAC_BUF(mac);

	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
		if (copy_from_user(&ifr, argp, sizeof ifr))
			return -EFAULT;

	if (cmd == TUNSETIFF && !tun) {
		int err;

		ifr.ifr_name[IFNAMSIZ-1] = '\0';

		rtnl_lock();
		err = tun_set_iff(file, &ifr);
		rtnl_unlock();

		if (err)
			return err;

		if (copy_to_user(argp, &ifr, sizeof(ifr)))
			return -EFAULT;
		return 0;
	}

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);

	switch (cmd) {
	case TUNSETNOCSUM:
		/* Disable/Enable checksum */
		if (arg)
			tun->flags |= TUN_NOCHECKSUM;
		else
			tun->flags &= ~TUN_NOCHECKSUM;

		DBG(KERN_INFO "%s: checksum %s\n",
		    tun->dev->name, arg ? "disabled" : "enabled");
		break;

	case TUNSETPERSIST:
		/* Disable/Enable persist mode */
		if (arg)
			tun->flags |= TUN_PERSIST;
		else
			tun->flags &= ~TUN_PERSIST;

		DBG(KERN_INFO "%s: persist %s\n",
		    tun->dev->name, arg ? "enabled" : "disabled");
		break;

	case TUNSETOWNER:
		/* Set owner of the device */
		tun->owner = (uid_t) arg;

		DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
		break;

	case TUNSETGROUP:
		/* Set group of the device */
		tun->group= (gid_t) arg;

		DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
		break;

	case TUNSETLINK:
		/* Only allow setting the type when the interface is down */
		if (tun->dev->flags & IFF_UP) {
			DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
				tun->dev->name);
			return -EBUSY;
		} else {
			tun->dev->type = (int) arg;
			DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
		}
		break;

#ifdef TUN_DEBUG
	case TUNSETDEBUG:
		tun->debug = arg;
		break;
#endif

	case SIOCGIFFLAGS:
		ifr.ifr_flags = tun->if_flags;
		if (copy_to_user( argp, &ifr, sizeof ifr))
			return -EFAULT;
		return 0;

	case SIOCSIFFLAGS:
		/** Set the character device's interface flags. Currently only
		 * IFF_PROMISC and IFF_ALLMULTI are used. */
		tun->if_flags = ifr.ifr_flags;
		DBG(KERN_INFO "%s: interface flags 0x%lx\n",
				tun->dev->name, tun->if_flags);
		return 0;

	case SIOCGIFHWADDR:
		/* Note: the actual net device's address may be different */
		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
				min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
		if (copy_to_user( argp, &ifr, sizeof ifr))
			return -EFAULT;
		return 0;

	case SIOCSIFHWADDR:
	{
		/* try to set the actual net device's hw address */
		int ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);

		if (ret == 0) {
			/** Set the character device's hardware address. This is used when
			 * filtering packets being sent from the network device to the character
			 * device. */
			memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
					min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
			DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
					tun->dev->name,
					tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
					tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
		}

		return  ret;
	}

	case SIOCADDMULTI:
		/** Add the specified group to the character device's multicast filter
		 * list. */
		add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
		DBG(KERN_DEBUG "%s: add multi: %s\n",
		    tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
		return 0;

	case SIOCDELMULTI:
		/** Remove the specified group from the character device's multicast
		 * filter list. */
		del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
		DBG(KERN_DEBUG "%s: del multi: %s\n",
		    tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
		return 0;

	default:
		return -EINVAL;
	};

	return 0;
}

static int tun_chr_fasync(int fd, struct file *file, int on)
{
	struct tun_struct *tun = file->private_data;
	int ret;

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);

	if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
		return ret;

	if (on) {
		ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
		if (ret)
			return ret;
		tun->flags |= TUN_FASYNC;
	} else
		tun->flags &= ~TUN_FASYNC;

	return 0;
}

static int tun_chr_open(struct inode *inode, struct file * file)
{
	DBG1(KERN_INFO "tunX: tun_chr_open\n");
	file->private_data = NULL;
	return 0;
}

static int tun_chr_close(struct inode *inode, struct file *file)
{
	struct tun_struct *tun = file->private_data;

	if (!tun)
		return 0;

	DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);

	tun_chr_fasync(-1, file, 0);

	rtnl_lock();

	/* Detach from net device */
	file->private_data = NULL;
	tun->attached = 0;

	/* Drop read queue */
	skb_queue_purge(&tun->readq);

	if (!(tun->flags & TUN_PERSIST)) {
		list_del(&tun->list);
		unregister_netdevice(tun->dev);
	}

	rtnl_unlock();

	return 0;
}

static const struct file_operations tun_fops = {
	.owner	= THIS_MODULE,
	.llseek = no_llseek,
	.read  = do_sync_read,
	.aio_read  = tun_chr_aio_read,
	.write = do_sync_write,
	.aio_write = tun_chr_aio_write,
	.poll	= tun_chr_poll,
	.ioctl	= tun_chr_ioctl,
	.open	= tun_chr_open,
	.release = tun_chr_close,
	.fasync = tun_chr_fasync
};

static struct miscdevice tun_miscdev = {
	.minor = TUN_MINOR,
	.name = "tun",
	.fops = &tun_fops,
};

/* ethtool interface */

static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	cmd->supported		= 0;
	cmd->advertising	= 0;
	cmd->speed		= SPEED_10;
	cmd->duplex		= DUPLEX_FULL;
	cmd->port		= PORT_TP;
	cmd->phy_address	= 0;
	cmd->transceiver	= XCVR_INTERNAL;
	cmd->autoneg		= AUTONEG_DISABLE;
	cmd->maxtxpkt		= 0;
	cmd->maxrxpkt		= 0;
	return 0;
}

static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
	struct tun_struct *tun = netdev_priv(dev);

	strcpy(info->driver, DRV_NAME);
	strcpy(info->version, DRV_VERSION);
	strcpy(info->fw_version, "N/A");

	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
		strcpy(info->bus_info, "tun");
		break;
	case TUN_TAP_DEV:
		strcpy(info->bus_info, "tap");
		break;
	}
}

static u32 tun_get_msglevel(struct net_device *dev)
{
#ifdef TUN_DEBUG
	struct tun_struct *tun = netdev_priv(dev);
	return tun->debug;
#else
	return -EOPNOTSUPP;
#endif
}

static void tun_set_msglevel(struct net_device *dev, u32 value)
{
#ifdef TUN_DEBUG
	struct tun_struct *tun = netdev_priv(dev);
	tun->debug = value;
#endif
}

static u32 tun_get_link(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
	return tun->attached;
}

static u32 tun_get_rx_csum(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
	return (tun->flags & TUN_NOCHECKSUM) == 0;
}

static int tun_set_rx_csum(struct net_device *dev, u32 data)
{
	struct tun_struct *tun = netdev_priv(dev);
	if (data)
		tun->flags &= ~TUN_NOCHECKSUM;
	else
		tun->flags |= TUN_NOCHECKSUM;
	return 0;
}

static const struct ethtool_ops tun_ethtool_ops = {
	.get_settings	= tun_get_settings,
	.get_drvinfo	= tun_get_drvinfo,
	.get_msglevel	= tun_get_msglevel,
	.set_msglevel	= tun_set_msglevel,
	.get_link	= tun_get_link,
	.get_rx_csum	= tun_get_rx_csum,
	.set_rx_csum	= tun_set_rx_csum
};

static int __init tun_init(void)
{
	int ret = 0;

	printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
	printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);

	ret = misc_register(&tun_miscdev);
	if (ret)
		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
	return ret;
}

static void tun_cleanup(void)
{
	struct tun_struct *tun, *nxt;

	misc_deregister(&tun_miscdev);

	rtnl_lock();
	list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
		DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
		unregister_netdevice(tun->dev);
	}
	rtnl_unlock();

}

module_init(tun_init);
module_exit(tun_cleanup);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(TUN_MINOR);