Commit fc54c658 authored Apr 16, 2008 by Pavel Emelyanov Committed by David S. Miller Apr 16, 2008

[TUN]: Allow to register tun devices in namespace.



This is basically means that a net is set for a new device, but
actually also involves two more steps:

1. mark the tun device as "local", i.e. do not allow for it to
   move across namespaces.

This is done so, since tun device is most often associated to some
file (and thus to some process) and moving the device alone is not
valid while keeping the file and the process outside. The need in 
ability to move a detached persistent device is to be investigated 
later.

2. get the tun device's net when tun becomes attached and put one
   when it becomes detached.

This is needed to handle the case when a task owning the tun dies,
but a files lives for some more time - in this case we must not
allow for net to be freed, since its exit hook will spoil that file's
private data by unregistering the tun from under tun_chr_close.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d647a591

drivers/net/tun.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -477,6 +477,7 @@ static void tun_setup(struct net_device *dev)
		dev->stop = tun_net_close;
		dev->ethtool_ops = &tun_ethtool_ops;
		dev->destructor = free_netdev;
		dev->features \|= NETIF_F_NETNS_LOCAL;
		}

		static struct tun_struct tun_get_by_name(struct tun_net tn, const char *name)
		@@ -544,6 +545,7 @@ static int tun_set_iff(struct net net, struct file file, struct ifreq *ifr)
		if (!dev)
		return -ENOMEM;

		dev_net_set(dev, net);
		tun = netdev_priv(dev);
		tun->dev = dev;
		tun->flags = flags;
		@@ -583,6 +585,7 @@ static int tun_set_iff(struct net net, struct file file, struct ifreq *ifr)

		file->private_data = tun;
		tun->attached = 1;
		get_net(dev_net(tun->dev));

		strcpy(ifr->ifr_name, tun->dev->name);
		return 0;
		@@ -798,6 +801,7 @@ static int tun_chr_close(struct inode inode, struct file file)
		/* Detach from net device */
		file->private_data = NULL;
		tun->attached = 0;
		put_net(dev_net(tun->dev));

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

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