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Commit 68ae9297 authored by Benjamin Poirier's avatar Benjamin Poirier Committed by Greg Kroah-Hartman
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net: mpls: Fix notifications when deleting a device 



commit 7d4741eacdefa5f0475431645b56baf00784df1f upstream.

There are various problems related to netlink notifications for mpls route
changes in response to interfaces being deleted:
* delete interface of only nexthop
	DELROUTE notification is missing RTA_OIF attribute
* delete interface of non-last nexthop
	NEWROUTE notification is missing entirely
* delete interface of last nexthop
	DELROUTE notification is missing nexthop

All of these problems stem from the fact that existing routes are modified
in-place before sending a notification. Restructure mpls_ifdown() to avoid
changing the route in the DELROUTE cases and to create a copy in the
NEWROUTE case.

Fixes: f8efb73c ("mpls: multipath route support")
Signed-off-by: default avatarBenjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 57af54a5

net/mpls/af_mpls.c

+52 −16
Original line number Diff line number Diff line
@@ -1438,22 +1438,52 @@ static void mpls_dev_destroy_rcu(struct rcu_head *head) 
	kfree(mdev);

}



static void mpls_ifdown(struct net_device *dev, int event)

static int mpls_ifdown(struct net_device *dev, int event)

{

	struct mpls_route __rcu **platform_label;

	struct net *net = dev_net(dev);

	u8 alive, deleted;

	unsigned index;



	platform_label = rtnl_dereference(net->mpls.platform_label);

	for (index = 0; index < net->mpls.platform_labels; index++) {

		struct mpls_route *rt = rtnl_dereference(platform_label[index]);

		bool nh_del = false;

		u8 alive = 0;



		if (!rt)

			continue;



		alive = 0;

		deleted = 0;

		if (event == NETDEV_UNREGISTER) {

			u8 deleted = 0;



			for_nexthops(rt) {

				struct net_device *nh_dev =

					rtnl_dereference(nh->nh_dev);



				if (!nh_dev || nh_dev == dev)

					deleted++;

				if (nh_dev == dev)

					nh_del = true;

			} endfor_nexthops(rt);



			/* if there are no more nexthops, delete the route */

			if (deleted == rt->rt_nhn) {

				mpls_route_update(net, index, NULL, NULL);

				continue;

			}



			if (nh_del) {

				size_t size = sizeof(*rt) + rt->rt_nhn *

					rt->rt_nh_size;

				struct mpls_route *orig = rt;



				rt = kmalloc(size, GFP_KERNEL);

				if (!rt)

					return -ENOMEM;

				memcpy(rt, orig, size);

			}

		}



		change_nexthops(rt) {

			unsigned int nh_flags = nh->nh_flags;
@@ -1477,16 +1507,15 @@ static void mpls_ifdown(struct net_device *dev, int event) 
next:

			if (!(nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)))

				alive++;

			if (!rtnl_dereference(nh->nh_dev))

				deleted++;

		} endfor_nexthops(rt);



		WRITE_ONCE(rt->rt_nhn_alive, alive);



		/* if there are no more nexthops, delete the route */

		if (event == NETDEV_UNREGISTER && deleted == rt->rt_nhn)

			mpls_route_update(net, index, NULL, NULL);

		if (nh_del)

			mpls_route_update(net, index, rt, NULL);

	}



	return 0;

}



static void mpls_ifup(struct net_device *dev, unsigned int flags)
@@ -1554,8 +1583,12 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event, 
		return NOTIFY_OK;



	switch (event) {

		int err;



	case NETDEV_DOWN:

		mpls_ifdown(dev, event);

		err = mpls_ifdown(dev, event);

		if (err)

			return notifier_from_errno(err);

		break;

	case NETDEV_UP:

		flags = dev_get_flags(dev);
@@ -1566,13 +1599,18 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event, 
		break;

	case NETDEV_CHANGE:

		flags = dev_get_flags(dev);

		if (flags & (IFF_RUNNING | IFF_LOWER_UP))

		if (flags & (IFF_RUNNING | IFF_LOWER_UP)) {

			mpls_ifup(dev, RTNH_F_DEAD | RTNH_F_LINKDOWN);

		else

			mpls_ifdown(dev, event);

		} else {

			err = mpls_ifdown(dev, event);

			if (err)

				return notifier_from_errno(err);

		}

		break;

	case NETDEV_UNREGISTER:

		mpls_ifdown(dev, event);

		err = mpls_ifdown(dev, event);

		if (err)

			return notifier_from_errno(err);

		mdev = mpls_dev_get(dev);

		if (mdev) {

			mpls_dev_sysctl_unregister(dev, mdev);
@@ -1583,8 +1621,6 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event, 
	case NETDEV_CHANGENAME:

		mdev = mpls_dev_get(dev);

		if (mdev) {

			int err;



			mpls_dev_sysctl_unregister(dev, mdev);

			err = mpls_dev_sysctl_register(dev, mdev);

			if (err)