1 files changed, 129 insertions, 50 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 41954e42a2de..03fdc5ae66b0 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -118,6 +118,40 @@ 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) {
+		write_lock_bh(&n->tbl->lock);
+		list_del_init(&n->gc_list);
+		write_unlock_bh(&n->tbl->lock);
+
+		atomic_dec(&n->tbl->gc_entries);
+	} else if (!new_is_perm && !on_gc_list) {
+		/* add entries to the tail; cleaning removes from the front */
+		write_lock_bh(&n->tbl->lock);
+		list_add_tail(&n->gc_list, &n->tbl->gc_list);
+		write_unlock_bh(&n->tbl->lock);
+
+		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 +166,7 @@ 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 +200,31 @@ 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 +293,7 @@ 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 +353,18 @@ 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 +377,7 @@ 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 +396,15 @@ static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device
 	n->tbl		  = tbl;
 	refcount_set(&n->refcnt, 1);
 	n->dead		  = 1;
+	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 +547,15 @@ 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) {
@@ -574,6 +618,9 @@ struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 	}
 
 	n->dead = 0;
+	if (!permanent)
+		list_add_tail(&n->gc_list, &n->tbl->gc_list);
+
 	if (want_ref)
 		neigh_hold(n);
 	rcu_assign_pointer(n->next,
@@ -591,6 +638,12 @@ 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 +907,7 @@ 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;
@@ -1137,8 +1190,9 @@ static void neigh_update_hhs(struct neighbour *neigh)
    Caller MUST hold reference count on the entry.
  */
 
-int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
-		 u32 flags, u32 nlmsg_pid)
+static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
+			  u8 new, u32 flags, u32 nlmsg_pid,
+			  struct netlink_ext_ack *extack)
 {
 	u8 old;
 	int err;
@@ -1155,8 +1209,10 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 	if (!(flags & NEIGH_UPDATE_F_ADMIN) &&
 	    (old & (NUD_NOARP | NUD_PERMANENT)))
 		goto out;
-	if (neigh->dead)
+	if (neigh->dead) {
+		NL_SET_ERR_MSG(extack, "Neighbor entry is now dead");
 		goto out;
+	}
 
 	neigh_update_ext_learned(neigh, flags, &notify);
 
@@ -1164,7 +1220,7 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 		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)) &&
@@ -1193,8 +1249,10 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 		   use it, otherwise discard the request.
 		 */
 		err = -EINVAL;
-		if (!(old & NUD_VALID))
+		if (!(old & NUD_VALID)) {
+			NL_SET_ERR_MSG(extack, "No link layer address given");
 			goto out;
+		}
 		lladdr = neigh->ha;
 	}
 
@@ -1241,7 +1299,7 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 						((new & NUD_REACHABLE) ?
 						 neigh->parms->reachable_time :
 						 0)));
-		neigh->nud_state = new;
+		neigh_change_state(neigh, new);
 		notify = 1;
 	}
 
@@ -1307,6 +1365,12 @@ out:
 
 	return err;
 }
+
+int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
+		 u32 flags, u32 nlmsg_pid)
+{
+	return __neigh_update(neigh, lladdr, new, flags, nlmsg_pid, NULL);
+}
 EXPORT_SYMBOL(neigh_update);
 
 /* Update the neigh to listen temporarily for probe responses, even if it is
@@ -1571,6 +1635,7 @@ 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);
@@ -1678,8 +1743,10 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto out;
 
 	dst_attr = nlmsg_find_attr(nlh, sizeof(*ndm), NDA_DST);
-	if (dst_attr == NULL)
+	if (!dst_attr) {
+		NL_SET_ERR_MSG(extack, "Network address not specified");
 		goto out;
+	}
 
 	ndm = nlmsg_data(nlh);
 	if (ndm->ndm_ifindex) {
@@ -1694,8 +1761,10 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (tbl == NULL)
 		return -EAFNOSUPPORT;
 
-	if (nla_len(dst_attr) < (int)tbl->key_len)
+	if (nla_len(dst_attr) < (int)tbl->key_len) {
+		NL_SET_ERR_MSG(extack, "Invalid network address");
 		goto out;
+	}
 
 	if (ndm->ndm_flags & NTF_PROXY) {
 		err = pneigh_delete(tbl, net, nla_data(dst_attr), dev);
@@ -1711,10 +1780,9 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto out;
 	}
 
-	err = neigh_update(neigh, NULL, NUD_FAILED,
-			   NEIGH_UPDATE_F_OVERRIDE |
-			   NEIGH_UPDATE_F_ADMIN,
-			   NETLINK_CB(skb).portid);
+	err = __neigh_update(neigh, NULL, NUD_FAILED,
+			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN,
+			     NETLINK_CB(skb).portid, extack);
 	write_lock_bh(&tbl->lock);
 	neigh_release(neigh);
 	neigh_remove_one(neigh, tbl);
@@ -1744,8 +1812,10 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto out;
 
 	err = -EINVAL;
-	if (tb[NDA_DST] == NULL)
+	if (!tb[NDA_DST]) {
+		NL_SET_ERR_MSG(extack, "Network address not specified");
 		goto out;
+	}
 
 	ndm = nlmsg_data(nlh);
 	if (ndm->ndm_ifindex) {
@@ -1755,16 +1825,21 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 			goto out;
 		}
 
-		if (tb[NDA_LLADDR] && nla_len(tb[NDA_LLADDR]) < dev->addr_len)
+		if (tb[NDA_LLADDR] && nla_len(tb[NDA_LLADDR]) < dev->addr_len) {
+			NL_SET_ERR_MSG(extack, "Invalid link address");
 			goto out;
+		}
 	}
 
 	tbl = neigh_find_table(ndm->ndm_family);
 	if (tbl == NULL)
 		return -EAFNOSUPPORT;
 
-	if (nla_len(tb[NDA_DST]) < (int)tbl->key_len)
+	if (nla_len(tb[NDA_DST]) < (int)tbl->key_len) {
+		NL_SET_ERR_MSG(extack, "Invalid network address");
 		goto out;
+	}
+
 	dst = nla_data(tb[NDA_DST]);
 	lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL;
 
@@ -1780,8 +1855,10 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto out;
 	}
 
-	if (dev == NULL)
+	if (!dev) {
+		NL_SET_ERR_MSG(extack, "Device not specified");
 		goto out;
+	}
 
 	neigh = neigh_lookup(tbl, dst, dev);
 	if (neigh == NULL) {
@@ -1790,7 +1867,9 @@ 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;
@@ -1817,8 +1896,8 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 		neigh_event_send(neigh, NULL);
 		err = 0;
 	} else
-		err = neigh_update(neigh, lladdr, ndm->ndm_state, flags,
-				   NETLINK_CB(skb).portid);
+		err = __neigh_update(neigh, lladdr, ndm->ndm_state, flags,
+				     NETLINK_CB(skb).portid, extack);
 	neigh_release(neigh);
 
 out:
@@ -2631,7 +2710,7 @@ 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);