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Commit e997f8a2 authored by David Ahern's avatar David Ahern Committed by David S. Miller
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neighbor: Remove externally learned entries from gc_list



Externally learned entries are similar to PERMANENT entries in the
sense they are managed by userspace and can not be garbage collected.
As such remove them from the gc_list, remove the flags check from
neigh_forced_gc and skip threshold checks in neigh_alloc. As with
PERMANENT entries, this allows unlimited number of NTF_EXT_LEARNED
entries.
Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 526f1b58
......@@ -129,21 +129,22 @@ static void neigh_mark_dead(struct neighbour *n)
static void neigh_update_gc_list(struct neighbour *n)
{
bool on_gc_list, new_is_perm;
bool on_gc_list, exempt_from_gc;
write_lock_bh(&n->tbl->lock);
write_lock(&n->lock);
/* remove from the gc list if new state is permanent;
* add to the gc list if new state is not permanent
/* remove from the gc list if new state is permanent or if neighbor
* is externally learned; otherwise entry should be on the gc list
*/
new_is_perm = n->nud_state & NUD_PERMANENT;
exempt_from_gc = n->nud_state & NUD_PERMANENT ||
n->flags & NTF_EXT_LEARNED;
on_gc_list = !list_empty(&n->gc_list);
if (new_is_perm && on_gc_list) {
if (exempt_from_gc && on_gc_list) {
list_del_init(&n->gc_list);
atomic_dec(&n->tbl->gc_entries);
} else if (!new_is_perm && !on_gc_list) {
} else if (!exempt_from_gc && !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);
......@@ -153,13 +154,14 @@ static void neigh_update_gc_list(struct neighbour *n)
write_unlock_bh(&n->tbl->lock);
}
static void neigh_update_ext_learned(struct neighbour *neigh, u32 flags,
static bool neigh_update_ext_learned(struct neighbour *neigh, u32 flags,
int *notify)
{
bool rc = false;
u8 ndm_flags;
if (!(flags & NEIGH_UPDATE_F_ADMIN))
return;
return rc;
ndm_flags = (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0;
if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) {
......@@ -167,8 +169,11 @@ static void neigh_update_ext_learned(struct neighbour *neigh, u32 flags,
neigh->flags |= NTF_EXT_LEARNED;
else
neigh->flags &= ~NTF_EXT_LEARNED;
rc = true;
*notify = 1;
}
return rc;
}
static bool neigh_del(struct neighbour *n, struct neighbour __rcu **np,
......@@ -219,7 +224,6 @@ 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;
int shrunk = 0;
......@@ -233,7 +237,7 @@ static int neigh_forced_gc(struct neigh_table *tbl)
write_lock(&n->lock);
if ((n->nud_state == NUD_FAILED) ||
(!(n->flags & flags) && time_after(tref, n->updated)))
time_after(tref, n->updated))
remove = true;
write_unlock(&n->lock);
......@@ -371,13 +375,13 @@ EXPORT_SYMBOL(neigh_ifdown);
static struct neighbour *neigh_alloc(struct neigh_table *tbl,
struct net_device *dev,
bool permanent)
bool exempt_from_gc)
{
struct neighbour *n = NULL;
unsigned long now = jiffies;
int entries;
if (permanent)
if (exempt_from_gc)
goto do_alloc;
entries = atomic_inc_return(&tbl->gc_entries) - 1;
......@@ -419,7 +423,7 @@ out:
return n;
out_entries:
if (!permanent)
if (!exempt_from_gc)
atomic_dec(&tbl->gc_entries);
goto out;
}
......@@ -566,9 +570,9 @@ EXPORT_SYMBOL(neigh_lookup_nodev);
static struct neighbour *___neigh_create(struct neigh_table *tbl,
const void *pkey,
struct net_device *dev,
bool permanent, bool want_ref)
bool exempt_from_gc, bool want_ref)
{
struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, permanent);
struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, exempt_from_gc);
u32 hash_val;
unsigned int key_len = tbl->key_len;
int error;
......@@ -634,7 +638,7 @@ static struct neighbour *___neigh_create(struct neigh_table *tbl,
}
n->dead = 0;
if (!permanent)
if (!exempt_from_gc)
list_add_tail(&n->gc_list, &n->tbl->gc_list);
if (want_ref)
......@@ -1210,6 +1214,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
u8 new, u32 flags, u32 nlmsg_pid,
struct netlink_ext_ack *extack)
{
bool ext_learn_change = false;
u8 old;
int err;
int notify = 0;
......@@ -1230,7 +1235,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
goto out;
}
neigh_update_ext_learned(neigh, flags, &notify);
ext_learn_change = neigh_update_ext_learned(neigh, flags, &notify);
if (!(new & NUD_VALID)) {
neigh_del_timer(neigh);
......@@ -1376,7 +1381,7 @@ out:
neigh_update_is_router(neigh, flags, &notify);
write_unlock_bh(&neigh->lock);
if ((new ^ old) & NUD_PERMANENT)
if (((new ^ old) & NUD_PERMANENT) || ext_learn_change)
neigh_update_gc_list(neigh);
if (notify)
......@@ -1881,14 +1886,16 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
neigh = neigh_lookup(tbl, dst, dev);
if (neigh == NULL) {
bool exempt_from_gc;
if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
err = -ENOENT;
goto out;
}
neigh = ___neigh_create(tbl, dst, dev,
ndm->ndm_state & NUD_PERMANENT,
true);
exempt_from_gc = ndm->ndm_state & NUD_PERMANENT ||
ndm->ndm_flags & NTF_EXT_LEARNED;
neigh = ___neigh_create(tbl, dst, dev, exempt_from_gc, true);
if (IS_ERR(neigh)) {
err = PTR_ERR(neigh);
goto out;
......
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