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-rw-r--r--Documentation/networking/ip-sysctl.txt4
-rw-r--r--include/net/neighbour.h3
-rw-r--r--net/core/neighbour.c119
3 files changed, 90 insertions, 36 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index af2a69439b93..acdfb5d2bcaa 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -108,8 +108,8 @@ neigh/default/gc_thresh2 - INTEGER
Default: 512
neigh/default/gc_thresh3 - INTEGER
- Maximum number of neighbor entries allowed. Increase this
- when using large numbers of interfaces and when communicating
+ Maximum number of non-PERMANENT neighbor entries allowed. Increase
+ this when using large numbers of interfaces and when communicating
with large numbers of directly-connected peers.
Default: 1024
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index f58b384aa6c9..6c13072910ab 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -154,6 +154,7 @@ struct neighbour {
struct hh_cache hh;
int (*output)(struct neighbour *, struct sk_buff *);
const struct neigh_ops *ops;
+ struct list_head gc_list;
struct rcu_head rcu;
struct net_device *dev;
u8 primary_key[0];
@@ -214,6 +215,8 @@ struct neigh_table {
struct timer_list proxy_timer;
struct sk_buff_head proxy_queue;
atomic_t entries;
+ atomic_t gc_entries;
+ struct list_head gc_list;
rwlock_t lock;
unsigned long last_rand;
struct neigh_statistics __percpu *stats;
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 6d479b5562be..c3b58712e98b 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -118,6 +118,34 @@ unsigned long neigh_rand_reach_time(unsigned long base)
}
EXPORT_SYMBOL(neigh_rand_reach_time);
+static void neigh_mark_dead(struct neighbour *n)
+{
+ n->dead = 1;
+ if (!list_empty(&n->gc_list)) {
+ list_del_init(&n->gc_list);
+ atomic_dec(&n->tbl->gc_entries);
+ }
+}
+
+static void neigh_change_state(struct neighbour *n, u8 new)
+{
+ bool on_gc_list = !list_empty(&n->gc_list);
+ bool new_is_perm = new & NUD_PERMANENT;
+
+ n->nud_state = new;
+
+ /* remove from the gc list if new state is permanent;
+ * add to the gc list if new state is not permanent
+ */
+ if (new_is_perm && on_gc_list) {
+ list_del_init(&n->gc_list);
+ atomic_dec(&n->tbl->gc_entries);
+ } else if (!new_is_perm && !on_gc_list) {
+ /* add entries to the tail; cleaning removes from the front */
+ list_add_tail(&n->gc_list, &n->tbl->gc_list);
+ atomic_inc(&n->tbl->gc_entries);
+ }
+}
static bool neigh_del(struct neighbour *n, __u8 state, __u8 flags,
struct neighbour __rcu **np, struct neigh_table *tbl)
@@ -132,7 +160,7 @@ static bool neigh_del(struct neighbour *n, __u8 state, __u8 flags,
neigh = rcu_dereference_protected(n->next,
lockdep_is_held(&tbl->lock));
rcu_assign_pointer(*np, neigh);
- n->dead = 1;
+ neigh_mark_dead(n);
retval = true;
}
write_unlock(&n->lock);
@@ -166,32 +194,31 @@ bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl)
static int neigh_forced_gc(struct neigh_table *tbl)
{
+ int max_clean = atomic_read(&tbl->gc_entries) - tbl->gc_thresh2;
+ unsigned long tref = jiffies - 5 * HZ;
+ u8 flags = NTF_EXT_LEARNED;
+ struct neighbour *n, *tmp;
+ u8 state = NUD_PERMANENT;
int shrunk = 0;
- int i;
- struct neigh_hash_table *nht;
NEIGH_CACHE_STAT_INC(tbl, forced_gc_runs);
write_lock_bh(&tbl->lock);
- nht = rcu_dereference_protected(tbl->nht,
- lockdep_is_held(&tbl->lock));
- for (i = 0; i < (1 << nht->hash_shift); i++) {
- struct neighbour *n;
- struct neighbour __rcu **np;
- np = &nht->hash_buckets[i];
- while ((n = rcu_dereference_protected(*np,
- lockdep_is_held(&tbl->lock))) != NULL) {
- /* Neighbour record may be discarded if:
- * - nobody refers to it.
- * - it is not permanent
- */
- if (neigh_del(n, NUD_PERMANENT, NTF_EXT_LEARNED, np,
- tbl)) {
- shrunk = 1;
- continue;
- }
- np = &n->next;
+ list_for_each_entry_safe(n, tmp, &tbl->gc_list, gc_list) {
+ if (refcount_read(&n->refcnt) == 1) {
+ bool remove = false;
+
+ write_lock(&n->lock);
+ if (!(n->nud_state & state) && !(n->flags & flags) &&
+ time_after(tref, n->updated))
+ remove = true;
+ write_unlock(&n->lock);
+
+ if (remove && neigh_remove_one(n, tbl))
+ shrunk++;
+ if (shrunk >= max_clean)
+ break;
}
}
@@ -260,8 +287,7 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
lockdep_is_held(&tbl->lock)));
write_lock(&n->lock);
neigh_del_timer(n);
- n->dead = 1;
-
+ neigh_mark_dead(n);
if (refcount_read(&n->refcnt) != 1) {
/* The most unpleasant situation.
We must destroy neighbour entry,
@@ -321,13 +347,18 @@ int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev)
}
EXPORT_SYMBOL(neigh_ifdown);
-static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device *dev)
+static struct neighbour *neigh_alloc(struct neigh_table *tbl,
+ struct net_device *dev,
+ bool permanent)
{
struct neighbour *n = NULL;
unsigned long now = jiffies;
int entries;
- entries = atomic_inc_return(&tbl->entries) - 1;
+ if (permanent)
+ goto do_alloc;
+
+ entries = atomic_inc_return(&tbl->gc_entries) - 1;
if (entries >= tbl->gc_thresh3 ||
(entries >= tbl->gc_thresh2 &&
time_after(now, tbl->last_flush + 5 * HZ))) {
@@ -340,6 +371,7 @@ static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device
}
}
+do_alloc:
n = kzalloc(tbl->entry_size + dev->neigh_priv_len, GFP_ATOMIC);
if (!n)
goto out_entries;
@@ -358,11 +390,19 @@ static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device
n->tbl = tbl;
refcount_set(&n->refcnt, 1);
n->dead = 1;
+
+ if (!permanent)
+ list_add_tail(&n->gc_list, &n->tbl->gc_list);
+ else
+ INIT_LIST_HEAD(&n->gc_list);
+
+ atomic_inc(&tbl->entries);
out:
return n;
out_entries:
- atomic_dec(&tbl->entries);
+ if (!permanent)
+ atomic_dec(&tbl->gc_entries);
goto out;
}
@@ -505,13 +545,15 @@ struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
}
EXPORT_SYMBOL(neigh_lookup_nodev);
-struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
- struct net_device *dev, bool want_ref)
+static struct neighbour *___neigh_create(struct neigh_table *tbl,
+ const void *pkey,
+ struct net_device *dev,
+ bool permanent, bool want_ref)
{
+ struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, permanent);
u32 hash_val;
unsigned int key_len = tbl->key_len;
int error;
- struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev);
struct neigh_hash_table *nht;
if (!n) {
@@ -591,6 +633,12 @@ out_neigh_release:
neigh_release(n);
goto out;
}
+
+struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
+ struct net_device *dev, bool want_ref)
+{
+ return ___neigh_create(tbl, pkey, dev, false, want_ref);
+}
EXPORT_SYMBOL(__neigh_create);
static u32 pneigh_hash(const void *pkey, unsigned int key_len)
@@ -854,7 +902,7 @@ static void neigh_periodic_work(struct work_struct *work)
(state == NUD_FAILED ||
time_after(jiffies, n->used + NEIGH_VAR(n->parms, GC_STALETIME)))) {
*np = n->next;
- n->dead = 1;
+ neigh_mark_dead(n);
write_unlock(&n->lock);
neigh_cleanup_and_release(n);
continue;
@@ -1167,7 +1215,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
neigh_del_timer(neigh);
if (old & NUD_CONNECTED)
neigh_suspect(neigh);
- neigh->nud_state = new;
+ neigh_change_state(neigh, new);
err = 0;
notify = old & NUD_VALID;
if ((old & (NUD_INCOMPLETE | NUD_PROBE)) &&
@@ -1246,7 +1294,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
((new & NUD_REACHABLE) ?
neigh->parms->reachable_time :
0)));
- neigh->nud_state = new;
+ neigh_change_state(neigh, new);
notify = 1;
}
@@ -1582,6 +1630,7 @@ void neigh_table_init(int index, struct neigh_table *tbl)
unsigned long phsize;
INIT_LIST_HEAD(&tbl->parms_list);
+ INIT_LIST_HEAD(&tbl->gc_list);
list_add(&tbl->parms.list, &tbl->parms_list);
write_pnet(&tbl->parms.net, &init_net);
refcount_set(&tbl->parms.refcnt, 1);
@@ -1813,7 +1862,9 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
goto out;
}
- neigh = __neigh_lookup_errno(tbl, dst, dev);
+ neigh = ___neigh_create(tbl, dst, dev,
+ ndm->ndm_state & NUD_PERMANENT,
+ true);
if (IS_ERR(neigh)) {
err = PTR_ERR(neigh);
goto out;
@@ -2654,7 +2705,7 @@ void __neigh_for_each_release(struct neigh_table *tbl,
rcu_assign_pointer(*np,
rcu_dereference_protected(n->next,
lockdep_is_held(&tbl->lock)));
- n->dead = 1;
+ neigh_mark_dead(n);
} else
np = &n->next;
write_unlock(&n->lock);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.