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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: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2018-12-11 18:57:25 -07:00 committed by David S. Miller
parent 526f1b587c
commit e997f8a20a
1 changed files with 28 additions and 21 deletions
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49
net/core/neighbour.c
View File

@ -129,21 +129,22 @@ static void neigh_mark_dead(struct neighbour *n)
static void neigh_update_gc_list(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_bh(&n->tbl->lock);
write_lock(&n->lock); write_lock(&n->lock);
/* remove from the gc list if new state is permanent; /* remove from the gc list if new state is permanent or if neighbor
* add to the gc list if new state is not permanent * 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); 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); list_del_init(&n->gc_list);
atomic_dec(&n->tbl->gc_entries); 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 */ /* add entries to the tail; cleaning removes from the front */
list_add_tail(&n->gc_list, &n->tbl->gc_list); list_add_tail(&n->gc_list, &n->tbl->gc_list);
atomic_inc(&n->tbl->gc_entries); 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); 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) int *notify)
{ {
bool rc = false;
u8 ndm_flags; u8 ndm_flags;
if (!(flags & NEIGH_UPDATE_F_ADMIN)) if (!(flags & NEIGH_UPDATE_F_ADMIN))
return; return rc;
ndm_flags = (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0; ndm_flags = (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0;
if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) { 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; neigh->flags |= NTF_EXT_LEARNED;
else else
neigh->flags &= ~NTF_EXT_LEARNED; neigh->flags &= ~NTF_EXT_LEARNED;
rc = true;
*notify = 1; *notify = 1;
} }
return rc;
} }
static bool neigh_del(struct neighbour *n, struct neighbour __rcu **np, 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; int max_clean = atomic_read(&tbl->gc_entries) - tbl->gc_thresh2;
unsigned long tref = jiffies - 5 * HZ; unsigned long tref = jiffies - 5 * HZ;
u8 flags = NTF_EXT_LEARNED;
struct neighbour *n, *tmp; struct neighbour *n, *tmp;
int shrunk = 0; int shrunk = 0;
@ -233,7 +237,7 @@ static int neigh_forced_gc(struct neigh_table *tbl)
write_lock(&n->lock); write_lock(&n->lock);
if ((n->nud_state == NUD_FAILED) || if ((n->nud_state == NUD_FAILED) ||
(!(n->flags & flags) && time_after(tref, n->updated))) time_after(tref, n->updated))
remove = true; remove = true;
write_unlock(&n->lock); write_unlock(&n->lock);
@ -371,13 +375,13 @@ EXPORT_SYMBOL(neigh_ifdown);
static struct neighbour *neigh_alloc(struct neigh_table *tbl, static struct neighbour *neigh_alloc(struct neigh_table *tbl,
struct net_device *dev, struct net_device *dev,
bool permanent) bool exempt_from_gc)
{ {
struct neighbour *n = NULL; struct neighbour *n = NULL;
unsigned long now = jiffies; unsigned long now = jiffies;
int entries; int entries;
if (permanent) if (exempt_from_gc)
goto do_alloc; goto do_alloc;
entries = atomic_inc_return(&tbl->gc_entries) - 1; entries = atomic_inc_return(&tbl->gc_entries) - 1;
@ -419,7 +423,7 @@ out:
return n; return n;
out_entries: out_entries:
if (!permanent) if (!exempt_from_gc)
atomic_dec(&tbl->gc_entries); atomic_dec(&tbl->gc_entries);
goto out; goto out;
} }
@ -566,9 +570,9 @@ EXPORT_SYMBOL(neigh_lookup_nodev);
static struct neighbour *___neigh_create(struct neigh_table *tbl, static struct neighbour *___neigh_create(struct neigh_table *tbl,
const void *pkey, const void *pkey,
struct net_device *dev, 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; u32 hash_val;
unsigned int key_len = tbl->key_len; unsigned int key_len = tbl->key_len;
int error; int error;
@ -634,7 +638,7 @@ static struct neighbour *___neigh_create(struct neigh_table *tbl,
} }
n->dead = 0; n->dead = 0;
if (!permanent) if (!exempt_from_gc)
list_add_tail(&n->gc_list, &n->tbl->gc_list); list_add_tail(&n->gc_list, &n->tbl->gc_list);
if (want_ref) if (want_ref)
@ -1210,6 +1214,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
u8 new, u32 flags, u32 nlmsg_pid, u8 new, u32 flags, u32 nlmsg_pid,
struct netlink_ext_ack *extack) struct netlink_ext_ack *extack)
{ {
bool ext_learn_change = false;
u8 old; u8 old;
int err; int err;
int notify = 0; int notify = 0;
@ -1230,7 +1235,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
goto out; goto out;
} }
neigh_update_ext_learned(neigh, flags, &notify); ext_learn_change = neigh_update_ext_learned(neigh, flags, &notify);
if (!(new & NUD_VALID)) { if (!(new & NUD_VALID)) {
neigh_del_timer(neigh); neigh_del_timer(neigh);
@ -1376,7 +1381,7 @@ out:
neigh_update_is_router(neigh, flags, &notify); neigh_update_is_router(neigh, flags, &notify);
write_unlock_bh(&neigh->lock); write_unlock_bh(&neigh->lock);
if ((new ^ old) & NUD_PERMANENT) if (((new ^ old) & NUD_PERMANENT) || ext_learn_change)
neigh_update_gc_list(neigh); neigh_update_gc_list(neigh);
if (notify) if (notify)
@ -1881,14 +1886,16 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
neigh = neigh_lookup(tbl, dst, dev); neigh = neigh_lookup(tbl, dst, dev);
if (neigh == NULL) { if (neigh == NULL) {
bool exempt_from_gc;
if (!(nlh->nlmsg_flags & NLM_F_CREATE)) { if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
err = -ENOENT; err = -ENOENT;
goto out; goto out;
} }
neigh = ___neigh_create(tbl, dst, dev, exempt_from_gc = ndm->ndm_state & NUD_PERMANENT ||
ndm->ndm_state & NUD_PERMANENT, ndm->ndm_flags & NTF_EXT_LEARNED;
true); neigh = ___neigh_create(tbl, dst, dev, exempt_from_gc, true);
if (IS_ERR(neigh)) { if (IS_ERR(neigh)) {
err = PTR_ERR(neigh); err = PTR_ERR(neigh);
goto out; goto out;