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: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 51cf848..67ddee5 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -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);