Commit d8a5ec67 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by David S. Miller
Browse files

[NET]: netlink support for moving devices between network namespaces. 



The simplest thing to implement is moving network devices between
namespaces.  However with the same attribute IFLA_NET_NS_PID we can
easily implement creating devices in the destination network
namespace as well.  However that is a little bit trickier so this
patch sticks to what is simple and easy.

A pid is used to identify a process that happens to be a member
of the network namespace we want to move the network device to.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ce286d32

include/linux/if_link.h

+1 −0
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ enum 
	IFLA_LINKMODE,

	IFLA_LINKINFO,

#define IFLA_LINKINFO IFLA_LINKINFO

	IFLA_NET_NS_PID,

	__IFLA_MAX

};

net/core/rtnetlink.c

+35 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <linux/security.h>

#include <linux/mutex.h>

#include <linux/if_addr.h>

#include <linux/nsproxy.h>



#include <asm/uaccess.h>

#include <asm/system.h>
@@ -727,6 +728,7 @@ const struct nla_policy ifla_policy[IFLA_MAX+1] = { 
	[IFLA_WEIGHT]		= { .type = NLA_U32 },

	[IFLA_OPERSTATE]	= { .type = NLA_U8 },

	[IFLA_LINKMODE]		= { .type = NLA_U8 },

	[IFLA_NET_NS_PID]	= { .type = NLA_U32 },

};



static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -734,12 +736,45 @@ static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = { 
	[IFLA_INFO_DATA]	= { .type = NLA_NESTED },

};



static struct net *get_net_ns_by_pid(pid_t pid)

{

	struct task_struct *tsk;

	struct net *net;



	/* Lookup the network namespace */

	net = ERR_PTR(-ESRCH);

	rcu_read_lock();

	tsk = find_task_by_pid(pid);

	if (tsk) {

		task_lock(tsk);

		if (tsk->nsproxy)

			net = get_net(tsk->nsproxy->net_ns);

		task_unlock(tsk);

	}

	rcu_read_unlock();

	return net;

}



static int do_setlink(struct net_device *dev, struct ifinfomsg *ifm,

		      struct nlattr **tb, char *ifname, int modified)

{

	int send_addr_notify = 0;

	int err;



	if (tb[IFLA_NET_NS_PID]) {

		struct net *net;

		net = get_net_ns_by_pid(nla_get_u32(tb[IFLA_NET_NS_PID]));

		if (IS_ERR(net)) {

			err = PTR_ERR(net);

			goto errout;

		}

		err = dev_change_net_namespace(dev, net, ifname);

		put_net(net);

		if (err)

			goto errout;

		modified = 1;

	}



	if (tb[IFLA_MAP]) {

		struct rtnl_link_ifmap *u_map;

		struct ifmap k_map;

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