Commit e997f8a2 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

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

net/core/neighbour.c

+28 −21
Original line number Diff line number Diff line
@@ -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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