Commit d2f0c9b1 authored by Ido Schimmel's avatar Ido Schimmel Committed by David S. Miller
Browse files

ipv6: Handle route deletion notification 



For the purpose of route offload, when a single route is deleted, it is
only of interest if it is the first route in the node or if it is
sibling to such a route.

In the first case, distinguish between several possibilities:

1. Route is the last route in the node. Emit a delete notification

2. Route is followed by a non-multipath route. Emit a replace
notification for the non-multipath route.

3. Route is followed by a multipath route. Emit a replace notification
for the multipath route.

In the second case, only emit a delete notification to ensure the route
is no longer used as a valid nexthop.

Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Reviewed-by: default avatarJiri Pirko <jiri@mellanox.com>
Reviewed-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9c6ecd3c

include/net/ip6_fib.h

+1 −0
Original line number Diff line number Diff line
@@ -487,6 +487,7 @@ int call_fib6_multipath_entry_notifiers(struct net *net, 
					struct fib6_info *rt,

					unsigned int nsiblings,

					struct netlink_ext_ack *extack);

int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt);

void fib6_rt_update(struct net *net, struct fib6_info *rt,

		    struct nl_info *info);

void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,

net/ipv6/ip6_fib.c

+43 −1
Original line number Diff line number Diff line
@@ -415,6 +415,18 @@ int call_fib6_multipath_entry_notifiers(struct net *net, 
	return call_fib6_notifiers(net, event_type, &info.info);

}



int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt)

{

	struct fib6_entry_notifier_info info = {

		.rt = rt,

		.nsiblings = rt->fib6_nsiblings,

	};



	rt->fib6_table->fib_seq++;

	return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE_TMP,

				   &info.info);

}



struct fib6_dump_arg {

	struct net *net;

	struct notifier_block *nb;
@@ -1910,13 +1922,29 @@ static struct fib6_node *fib6_repair_tree(struct net *net, 
static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,

			   struct fib6_info __rcu **rtp, struct nl_info *info)

{

	struct fib6_info *leaf, *replace_rt = NULL;

	struct fib6_walker *w;

	struct fib6_info *rt = rcu_dereference_protected(*rtp,

				    lockdep_is_held(&table->tb6_lock));

	struct net *net = info->nl_net;

	bool notify_del = false;



	RT6_TRACE("fib6_del_route\n");



	/* If the deleted route is the first in the node and it is not part of

	 * a multipath route, then we need to replace it with the next route

	 * in the node, if exists.

	 */

	leaf = rcu_dereference_protected(fn->leaf,

					 lockdep_is_held(&table->tb6_lock));

	if (leaf == rt && !rt->fib6_nsiblings) {

		if (rcu_access_pointer(rt->fib6_next))

			replace_rt = rcu_dereference_protected(rt->fib6_next,

					    lockdep_is_held(&table->tb6_lock));

		else

			notify_del = true;

	}



	/* Unlink it */

	*rtp = rt->fib6_next;

	rt->fib6_node = NULL;
@@ -1934,6 +1962,14 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, 
	if (rt->fib6_nsiblings) {

		struct fib6_info *sibling, *next_sibling;



		/* The route is deleted from a multipath route. If this

		 * multipath route is the first route in the node, then we need

		 * to emit a delete notification. Otherwise, we need to skip

		 * the notification.

		 */

		if (rt->fib6_metric == leaf->fib6_metric &&

		    rt6_qualify_for_ecmp(leaf))

			notify_del = true;

		list_for_each_entry_safe(sibling, next_sibling,

					 &rt->fib6_siblings, fib6_siblings)

			sibling->fib6_nsiblings--;
@@ -1969,8 +2005,14 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, 


	fib6_purge_rt(rt, fn, net);



	if (!info->skip_notify_kernel)

	if (!info->skip_notify_kernel) {

		if (notify_del)

			call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL_TMP,

						  rt, NULL);

		else if (replace_rt)

			call_fib6_entry_notifiers_replace(net, replace_rt);

		call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt, NULL);

	}

	if (!info->skip_notify)

		inet6_rt_notify(RTM_DELROUTE, rt, info, 0);

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