[NET]: Implement network device movement between namespaces
This patch introduces NETIF_F_NETNS_LOCAL a flag to indicate
a network device is local to a single network namespace and
should never be moved. Useful for pseudo devices that we
need an instance in each network namespace (like the loopback
device) and for any device we find that cannot handle multiple
network namespaces so we may trap them in the initial network
namespace.
This patch introduces the function dev_change_net_namespace
a function used to move a network device from one network
namespace to another. To the network device nothing
special appears to happen, to the components of the network
stack it appears as if the network device was unregistered
in the network namespace it is in, and a new device
was registered in the network namespace the device
was moved to.
This patch sets up a namespace device destructor that
upon the exit of a network namespace moves all of the
movable network devices to the initial network namespace
so they are not lost.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7353b3e..407658c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -449,6 +449,7 @@
#define NETIF_F_VLAN_CHALLENGED 1024 /* Device cannot handle VLAN packets */
#define NETIF_F_GSO 2048 /* Enable software GSO. */
#define NETIF_F_LLTX 4096 /* LockLess TX */
+#define NETIF_F_NETNS_LOCAL 8192 /* Does not change network namespaces */
#define NETIF_F_MULTI_QUEUE 16384 /* Has multiple TX/RX queues */
#define NETIF_F_LRO 32768 /* large receive offload */
@@ -1016,6 +1017,8 @@
extern unsigned dev_get_flags(const struct net_device *);
extern int dev_change_flags(struct net_device *, unsigned);
extern int dev_change_name(struct net_device *, char *);
+extern int dev_change_net_namespace(struct net_device *,
+ struct net *, const char *);
extern int dev_set_mtu(struct net_device *, int);
extern int dev_set_mac_address(struct net_device *,
struct sockaddr *);