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-rw-r--r--net/bridge/br_fdb.c35
-rw-r--r--net/bridge/br_private.h4
2 files changed, 37 insertions, 2 deletions
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 7738e1b56452..c622de5eccd0 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -329,11 +329,18 @@ static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f,
hlist_del_init_rcu(&f->fdb_node);
rhashtable_remove_fast(&br->fdb_hash_tbl, &f->rhnode,
br_fdb_rht_params);
+ if (test_and_clear_bit(BR_FDB_DYNAMIC_LEARNED, &f->flags))
+ atomic_dec(&br->fdb_n_learned);
fdb_notify(br, f, RTM_DELNEIGH, swdev_notify);
call_rcu(&f->rcu, fdb_rcu_free);
}
-/* Delete a local entry if no other port had the same address. */
+/* Delete a local entry if no other port had the same address.
+ *
+ * This function should only be called on entries with BR_FDB_LOCAL set,
+ * so even with BR_FDB_ADDED_BY_USER cleared we never need to increase
+ * the accounting for dynamically learned entries again.
+ */
static void fdb_delete_local(struct net_bridge *br,
const struct net_bridge_port *p,
struct net_bridge_fdb_entry *f)
@@ -388,9 +395,20 @@ static struct net_bridge_fdb_entry *fdb_create(struct net_bridge *br,
__u16 vid,
unsigned long flags)
{
+ bool learned = !test_bit(BR_FDB_ADDED_BY_USER, &flags) &&
+ !test_bit(BR_FDB_LOCAL, &flags);
+ u32 max_learned = READ_ONCE(br->fdb_max_learned);
struct net_bridge_fdb_entry *fdb;
int err;
+ if (likely(learned)) {
+ int n_learned = atomic_read(&br->fdb_n_learned);
+
+ if (unlikely(max_learned && n_learned >= max_learned))
+ return NULL;
+ __set_bit(BR_FDB_DYNAMIC_LEARNED, &flags);
+ }
+
fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
if (!fdb)
return NULL;
@@ -407,6 +425,9 @@ static struct net_bridge_fdb_entry *fdb_create(struct net_bridge *br,
return NULL;
}
+ if (likely(learned))
+ atomic_inc(&br->fdb_n_learned);
+
hlist_add_head_rcu(&fdb->fdb_node, &br->fdb_list);
return fdb;
@@ -912,8 +933,12 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
clear_bit(BR_FDB_LOCKED, &fdb->flags);
}
- if (unlikely(test_bit(BR_FDB_ADDED_BY_USER, &flags)))
+ if (unlikely(test_bit(BR_FDB_ADDED_BY_USER, &flags))) {
set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
+ if (test_and_clear_bit(BR_FDB_DYNAMIC_LEARNED,
+ &fdb->flags))
+ atomic_dec(&br->fdb_n_learned);
+ }
if (unlikely(fdb_modified)) {
trace_br_fdb_update(br, source, addr, vid, flags);
fdb_notify(br, fdb, RTM_NEWNEIGH, true);
@@ -1091,6 +1116,8 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
}
set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
+ if (test_and_clear_bit(BR_FDB_DYNAMIC_LEARNED, &fdb->flags))
+ atomic_dec(&br->fdb_n_learned);
}
if (fdb_to_nud(br, fdb) != state) {
@@ -1465,6 +1492,10 @@ int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
if (!p)
set_bit(BR_FDB_LOCAL, &fdb->flags);
+ if ((swdev_notify || !p) &&
+ test_and_clear_bit(BR_FDB_DYNAMIC_LEARNED, &fdb->flags))
+ atomic_dec(&br->fdb_n_learned);
+
if (modified)
fdb_notify(br, fdb, RTM_NEWNEIGH, swdev_notify);
}
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index cbbe35278459..27a7a06660f3 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -274,6 +274,7 @@ enum {
BR_FDB_NOTIFY,
BR_FDB_NOTIFY_INACTIVE,
BR_FDB_LOCKED,
+ BR_FDB_DYNAMIC_LEARNED,
};
struct net_bridge_fdb_key {
@@ -555,6 +556,9 @@ struct net_bridge {
struct kobject *ifobj;
u32 auto_cnt;
+ atomic_t fdb_n_learned;
+ u32 fdb_max_learned;
+
#ifdef CONFIG_NET_SWITCHDEV
/* Counter used to make sure that hardware domains get unique
* identifiers in case a bridge spans multiple switchdev instances.