Merge branch 'tuntap'

Pavel Emelyanov says:

====================
tun: Some bits required for tun's checkpoint-restore (v2)

After taking a closer look on tun checkpoint-restore I've found several
issues with the tun's API that make it impossible to dump and restore
the state of tun device and attached tun-files.

The proposed API changes are all about extending the existing ioctl-based
stuff. Patches fit today's net-next.

This v2 has David's comments about patch #1 fixed. All the rest is the same.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tun.c

@@ -138,7 +138,10 @@ struct tun_file {
 	struct fasync_struct *fasync;
 	/* only used for fasnyc */
 	unsigned int flags;
-	u16 queue_index;
+	union {
+		u16 queue_index;
+		unsigned int ifindex;
+	};
 	struct list_head next;
 	struct tun_struct *detached;
 };
@@ -498,7 +501,7 @@ static void tun_detach_all(struct net_device *dev)
 		module_put(THIS_MODULE);
 }
 
-static int tun_attach(struct tun_struct *tun, struct file *file)
+static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
 {
 	struct tun_file *tfile = file->private_data;
 	int err;
@@ -523,7 +526,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file)
 	err = 0;
 
 	/* Re-attach the filter to presist device */
-	if (tun->filter_attached == true) {
+	if (!skip_filter && (tun->filter_attached == true)) {
 		err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 		if (!err)
 			goto out;
@@ -1554,7 +1557,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 		if (err < 0)
 			return err;
 
-		err = tun_attach(tun, file);
+		err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
 		if (err < 0)
 			return err;
 
@@ -1601,6 +1604,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 
 		dev_net_set(dev, net);
 		dev->rtnl_link_ops = &tun_link_ops;
+		dev->ifindex = tfile->ifindex;
 
 		tun = netdev_priv(dev);
 		tun->dev = dev;
@@ -1627,7 +1631,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 		dev->vlan_features = dev->features;
 
 		INIT_LIST_HEAD(&tun->disabled);
-		err = tun_attach(tun, file);
+		err = tun_attach(tun, file, false);
 		if (err < 0)
 			goto err_free_dev;
 
@@ -1791,7 +1795,7 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr)
 		ret = security_tun_dev_attach_queue(tun->security);
 		if (ret < 0)
 			goto unlock;
-		ret = tun_attach(tun, file);
+		ret = tun_attach(tun, file, false);
 	} else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
 		tun = rtnl_dereference(tfile->tun);
 		if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
@@ -1817,6 +1821,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 	kgid_t group;
 	int sndbuf;
 	int vnet_hdr_sz;
+	unsigned int ifindex;
 	int ret;
 
 	if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
@@ -1851,6 +1856,19 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 			ret = -EFAULT;
 		goto unlock;
 	}
+	if (cmd == TUNSETIFINDEX) {
+		ret = -EPERM;
+		if (tun)
+			goto unlock;
+
+		ret = -EFAULT;
+		if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
+			goto unlock;
+
+		ret = 0;
+		tfile->ifindex = ifindex;
+		goto unlock;
+	}
 
 	ret = -EBADFD;
 	if (!tun)
@@ -1863,6 +1881,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 	case TUNGETIFF:
 		tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
 
+		if (tfile->detached)
+			ifr.ifr_flags |= IFF_DETACH_QUEUE;
+		if (!tfile->socket.sk->sk_filter)
+			ifr.ifr_flags |= IFF_NOFILTER;
+
 		if (copy_to_user(argp, &ifr, ifreq_len))
 			ret = -EFAULT;
 		break;
@@ -2019,6 +2042,16 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 		tun_detach_filter(tun, tun->numqueues);
 		break;
 
+	case TUNGETFILTER:
+		ret = -EINVAL;
+		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
+			break;
+		ret = -EFAULT;
+		if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
+			break;
+		ret = 0;
+		break;
+
 	default:
 		ret = -EINVAL;
 		break;
@@ -2099,6 +2132,7 @@ static int tun_chr_open(struct inode *inode, struct file * file)
 	rcu_assign_pointer(tfile->tun, NULL);
 	tfile->net = get_net(current->nsproxy->net_ns);
 	tfile->flags = 0;
+	tfile->ifindex = 0;
 
 	rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
 	init_waitqueue_head(&tfile->wq.wait);

include/uapi/linux/if_tun.h

@@ -56,6 +56,8 @@
 #define TUNGETVNETHDRSZ _IOR('T', 215, int)
 #define TUNSETVNETHDRSZ _IOW('T', 216, int)
 #define TUNSETQUEUE  _IOW('T', 217, int)
+#define TUNSETIFINDEX	_IOW('T', 218, unsigned int)
+#define TUNGETFILTER _IOR('T', 219, struct sock_fprog)
 
 /* TUNSETIFF ifr flags */
 #define IFF_TUN		0x0001
@@ -70,6 +72,7 @@
 #define IFF_DETACH_QUEUE 0x0400
 /* read-only flag */
 #define IFF_PERSIST	0x0800
+#define IFF_NOFILTER	0x1000
 
 /* Socket options */
 #define TUN_TX_TIMESTAMP 1