1 files changed, 221 insertions, 285 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 552719c3bbc3..49dce9a82295 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -14,7 +14,6 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/slab.h>
-#include <linux/kmemleak.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -61,6 +60,25 @@ static int pneigh_ifdown_and_unlock(struct neigh_table *tbl,
 static const struct seq_operations neigh_stat_seq_ops;
 #endif
 
+static struct hlist_head *neigh_get_dev_table(struct net_device *dev, int family)
+{
+	int i;
+
+	switch (family) {
+	default:
+		DEBUG_NET_WARN_ON_ONCE(1);
+		fallthrough; /* to avoid panic by null-ptr-deref */
+	case AF_INET:
+		i = NEIGH_ARP_TABLE;
+		break;
+	case AF_INET6:
+		i = NEIGH_ND_TABLE;
+		break;
+	}
+
+	return &dev->neighbours[i];
+}
+
 /*
    Neighbour hash table buckets are protected with rwlock tbl->lock.
 
@@ -205,18 +223,14 @@ static void neigh_update_flags(struct neighbour *neigh, u32 flags, int *notify,
 	}
 }
 
-static bool neigh_del(struct neighbour *n, struct neighbour __rcu **np,
-		      struct neigh_table *tbl)
+bool neigh_remove_one(struct neighbour *n)
 {
 	bool retval = false;
 
 	write_lock(&n->lock);
 	if (refcount_read(&n->refcnt) == 1) {
-		struct neighbour *neigh;
-
-		neigh = rcu_dereference_protected(n->next,
-						  lockdep_is_held(&tbl->lock));
-		rcu_assign_pointer(*np, neigh);
+		hlist_del_rcu(&n->hash);
+		hlist_del_rcu(&n->dev_list);
 		neigh_mark_dead(n);
 		retval = true;
 	}
@@ -226,29 +240,6 @@ static bool neigh_del(struct neighbour *n, struct neighbour __rcu **np,
 	return retval;
 }
 
-bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl)
-{
-	struct neigh_hash_table *nht;
-	void *pkey = ndel->primary_key;
-	u32 hash_val;
-	struct neighbour *n;
-	struct neighbour __rcu **np;
-
-	nht = rcu_dereference_protected(tbl->nht,
-					lockdep_is_held(&tbl->lock));
-	hash_val = tbl->hash(pkey, ndel->dev, nht->hash_rnd);
-	hash_val = hash_val >> (32 - nht->hash_shift);
-
-	np = &nht->hash_buckets[hash_val];
-	while ((n = rcu_dereference_protected(*np,
-					      lockdep_is_held(&tbl->lock)))) {
-		if (n == ndel)
-			return neigh_del(n, np, tbl);
-		np = &n->next;
-	}
-	return false;
-}
-
 static int neigh_forced_gc(struct neigh_table *tbl)
 {
 	int max_clean = atomic_read(&tbl->gc_entries) -
@@ -276,7 +267,7 @@ static int neigh_forced_gc(struct neigh_table *tbl)
 				remove = true;
 			write_unlock(&n->lock);
 
-			if (remove && neigh_remove_one(n, tbl))
+			if (remove && neigh_remove_one(n))
 				shrunk++;
 			if (shrunk >= max_clean)
 				break;
@@ -318,7 +309,7 @@ static void neigh_add_timer(struct neighbour *n, unsigned long when)
 static int neigh_del_timer(struct neighbour *n)
 {
 	if ((n->nud_state & NUD_IN_TIMER) &&
-	    del_timer(&n->timer)) {
+	    timer_delete(&n->timer)) {
 		neigh_release(n);
 		return 1;
 	}
@@ -380,54 +371,42 @@ static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net,
 static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
 			    bool skip_perm)
 {
-	int i;
-	struct neigh_hash_table *nht;
+	struct hlist_head *dev_head;
+	struct hlist_node *tmp;
+	struct neighbour *n;
 
-	nht = rcu_dereference_protected(tbl->nht,
-					lockdep_is_held(&tbl->lock));
+	dev_head = neigh_get_dev_table(dev, tbl->family);
 
-	for (i = 0; i < (1 << nht->hash_shift); i++) {
-		struct neighbour *n;
-		struct neighbour __rcu **np = &nht->hash_buckets[i];
+	hlist_for_each_entry_safe(n, tmp, dev_head, dev_list) {
+		if (skip_perm && n->nud_state & NUD_PERMANENT)
+			continue;
 
-		while ((n = rcu_dereference_protected(*np,
-					lockdep_is_held(&tbl->lock))) != NULL) {
-			if (dev && n->dev != dev) {
-				np = &n->next;
-				continue;
-			}
-			if (skip_perm && n->nud_state & NUD_PERMANENT) {
-				np = &n->next;
-				continue;
-			}
-			rcu_assign_pointer(*np,
-				   rcu_dereference_protected(n->next,
-						lockdep_is_held(&tbl->lock)));
-			write_lock(&n->lock);
-			neigh_del_timer(n);
-			neigh_mark_dead(n);
-			if (refcount_read(&n->refcnt) != 1) {
-				/* The most unpleasant situation.
-				   We must destroy neighbour entry,
-				   but someone still uses it.
-
-				   The destroy will be delayed until
-				   the last user releases us, but
-				   we must kill timers etc. and move
-				   it to safe state.
-				 */
-				__skb_queue_purge(&n->arp_queue);
-				n->arp_queue_len_bytes = 0;
-				WRITE_ONCE(n->output, neigh_blackhole);
-				if (n->nud_state & NUD_VALID)
-					n->nud_state = NUD_NOARP;
-				else
-					n->nud_state = NUD_NONE;
-				neigh_dbg(2, "neigh %p is stray\n", n);
-			}
-			write_unlock(&n->lock);
-			neigh_cleanup_and_release(n);
+		hlist_del_rcu(&n->hash);
+		hlist_del_rcu(&n->dev_list);
+		write_lock(&n->lock);
+		neigh_del_timer(n);
+		neigh_mark_dead(n);
+		if (refcount_read(&n->refcnt) != 1) {
+			/* The most unpleasant situation.
+			 * We must destroy neighbour entry,
+			 * but someone still uses it.
+			 *
+			 * The destroy will be delayed until
+			 * the last user releases us, but
+			 * we must kill timers etc. and move
+			 * it to safe state.
+			 */
+			__skb_queue_purge(&n->arp_queue);
+			n->arp_queue_len_bytes = 0;
+			WRITE_ONCE(n->output, neigh_blackhole);
+			if (n->nud_state & NUD_VALID)
+				n->nud_state = NUD_NOARP;
+			else
+				n->nud_state = NUD_NONE;
+			neigh_dbg(2, "neigh %p is stray\n", n);
 		}
+		write_unlock(&n->lock);
+		neigh_cleanup_and_release(n);
 	}
 }
 
@@ -448,7 +427,7 @@ static int __neigh_ifdown(struct neigh_table *tbl, struct net_device *dev,
 	pneigh_queue_purge(&tbl->proxy_queue, dev ? dev_net(dev) : NULL,
 			   tbl->family);
 	if (skb_queue_empty_lockless(&tbl->proxy_queue))
-		del_timer_sync(&tbl->proxy_timer);
+		timer_delete_sync(&tbl->proxy_timer);
 	return 0;
 }
 
@@ -530,27 +509,21 @@ static void neigh_get_hash_rnd(u32 *x)
 
 static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
 {
-	size_t size = (1 << shift) * sizeof(struct neighbour *);
+	size_t size = (1 << shift) * sizeof(struct hlist_head);
+	struct hlist_head *hash_heads;
 	struct neigh_hash_table *ret;
-	struct neighbour __rcu **buckets;
 	int i;
 
 	ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
 	if (!ret)
 		return NULL;
-	if (size <= PAGE_SIZE) {
-		buckets = kzalloc(size, GFP_ATOMIC);
-	} else {
-		buckets = (struct neighbour __rcu **)
-			  __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
-					   get_order(size));
-		kmemleak_alloc(buckets, size, 1, GFP_ATOMIC);
-	}
-	if (!buckets) {
+
+	hash_heads = kzalloc(size, GFP_ATOMIC);
+	if (!hash_heads) {
 		kfree(ret);
 		return NULL;
 	}
-	ret->hash_buckets = buckets;
+	ret->hash_heads = hash_heads;
 	ret->hash_shift = shift;
 	for (i = 0; i < NEIGH_NUM_HASH_RND; i++)
 		neigh_get_hash_rnd(&ret->hash_rnd[i]);
@@ -562,15 +535,8 @@ static void neigh_hash_free_rcu(struct rcu_head *head)
 	struct neigh_hash_table *nht = container_of(head,
 						    struct neigh_hash_table,
 						    rcu);
-	size_t size = (1 << nht->hash_shift) * sizeof(struct neighbour *);
-	struct neighbour __rcu **buckets = nht->hash_buckets;
 
-	if (size <= PAGE_SIZE) {
-		kfree(buckets);
-	} else {
-		kmemleak_free(buckets);
-		free_pages((unsigned long)buckets, get_order(size));
-	}
+	kfree(nht->hash_heads);
 	kfree(nht);
 }
 
@@ -589,24 +555,17 @@ static struct neigh_hash_table *neigh_hash_grow(struct neigh_table *tbl,
 		return old_nht;
 
 	for (i = 0; i < (1 << old_nht->hash_shift); i++) {
-		struct neighbour *n, *next;
+		struct hlist_node *tmp;
+		struct neighbour *n;
 
-		for (n = rcu_dereference_protected(old_nht->hash_buckets[i],
-						   lockdep_is_held(&tbl->lock));
-		     n != NULL;
-		     n = next) {
+		neigh_for_each_in_bucket_safe(n, tmp, &old_nht->hash_heads[i]) {
 			hash = tbl->hash(n->primary_key, n->dev,
 					 new_nht->hash_rnd);
 
 			hash >>= (32 - new_nht->hash_shift);
-			next = rcu_dereference_protected(n->next,
-						lockdep_is_held(&tbl->lock));
 
-			rcu_assign_pointer(n->next,
-					   rcu_dereference_protected(
-						new_nht->hash_buckets[hash],
-						lockdep_is_held(&tbl->lock)));
-			rcu_assign_pointer(new_nht->hash_buckets[hash], n);
+			hlist_del_rcu(&n->hash);
+			hlist_add_head_rcu(&n->hash, &new_nht->hash_heads[hash]);
 		}
 	}
 
@@ -693,11 +652,7 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey,
 		goto out_tbl_unlock;
 	}
 
-	for (n1 = rcu_dereference_protected(nht->hash_buckets[hash_val],
-					    lockdep_is_held(&tbl->lock));
-	     n1 != NULL;
-	     n1 = rcu_dereference_protected(n1->next,
-			lockdep_is_held(&tbl->lock))) {
+	neigh_for_each_in_bucket(n1, &nht->hash_heads[hash_val]) {
 		if (dev == n1->dev && !memcmp(n1->primary_key, n->primary_key, key_len)) {
 			if (want_ref)
 				neigh_hold(n1);
@@ -713,10 +668,11 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey,
 		list_add_tail(&n->managed_list, &n->tbl->managed_list);
 	if (want_ref)
 		neigh_hold(n);
-	rcu_assign_pointer(n->next,
-			   rcu_dereference_protected(nht->hash_buckets[hash_val],
-						     lockdep_is_held(&tbl->lock)));
-	rcu_assign_pointer(nht->hash_buckets[hash_val], n);
+	hlist_add_head_rcu(&n->hash, &nht->hash_heads[hash_val]);
+
+	hlist_add_head_rcu(&n->dev_list,
+			   neigh_get_dev_table(dev, tbl->family));
+
 	write_unlock_bh(&tbl->lock);
 	neigh_dbg(2, "neigh %p is created\n", n);
 	rc = n;
@@ -734,7 +690,9 @@ out_neigh_release:
 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 				 struct net_device *dev, bool want_ref)
 {
-	return ___neigh_create(tbl, pkey, dev, 0, false, want_ref);
+	bool exempt_from_gc = !!(dev->flags & IFF_LOOPBACK);
+
+	return ___neigh_create(tbl, pkey, dev, 0, exempt_from_gc, want_ref);
 }
 EXPORT_SYMBOL(__neigh_create);
 
@@ -874,12 +832,10 @@ static int pneigh_ifdown_and_unlock(struct neigh_table *tbl,
 	return -ENOENT;
 }
 
-static void neigh_parms_destroy(struct neigh_parms *parms);
-
 static inline void neigh_parms_put(struct neigh_parms *parms)
 {
 	if (refcount_dec_and_test(&parms->refcnt))
-		neigh_parms_destroy(parms);
+		kfree(parms);
 }
 
 /*
@@ -946,10 +902,10 @@ static void neigh_connect(struct neighbour *neigh)
 static void neigh_periodic_work(struct work_struct *work)
 {
 	struct neigh_table *tbl = container_of(work, struct neigh_table, gc_work.work);
+	struct neigh_hash_table *nht;
+	struct hlist_node *tmp;
 	struct neighbour *n;
-	struct neighbour __rcu **np;
 	unsigned int i;
-	struct neigh_hash_table *nht;
 
 	NEIGH_CACHE_STAT_INC(tbl, periodic_gc_runs);
 
@@ -974,10 +930,7 @@ static void neigh_periodic_work(struct work_struct *work)
 		goto out;
 
 	for (i = 0 ; i < (1 << nht->hash_shift); i++) {
-		np = &nht->hash_buckets[i];
-
-		while ((n = rcu_dereference_protected(*np,
-				lockdep_is_held(&tbl->lock))) != NULL) {
+		neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[i]) {
 			unsigned int state;
 
 			write_lock(&n->lock);
@@ -986,7 +939,7 @@ static void neigh_periodic_work(struct work_struct *work)
 			if ((state & (NUD_PERMANENT | NUD_IN_TIMER)) ||
 			    (n->flags & NTF_EXT_LEARNED)) {
 				write_unlock(&n->lock);
-				goto next_elt;
+				continue;
 			}
 
 			if (time_before(n->used, n->confirmed) &&
@@ -997,18 +950,14 @@ static void neigh_periodic_work(struct work_struct *work)
 			    (state == NUD_FAILED ||
 			     !time_in_range_open(jiffies, n->used,
 						 n->used + NEIGH_VAR(n->parms, GC_STALETIME)))) {
-				rcu_assign_pointer(*np,
-					rcu_dereference_protected(n->next,
-						lockdep_is_held(&tbl->lock)));
+				hlist_del_rcu(&n->hash);
+				hlist_del_rcu(&n->dev_list);
 				neigh_mark_dead(n);
 				write_unlock(&n->lock);
 				neigh_cleanup_and_release(n);
 				continue;
 			}
 			write_unlock(&n->lock);
-
-next_elt:
-			np = &n->next;
 		}
 		/*
 		 * It's fine to release lock here, even if hash table
@@ -1082,7 +1031,7 @@ static void neigh_probe(struct neighbour *neigh)
 static void neigh_timer_handler(struct timer_list *t)
 {
 	unsigned long now, next;
-	struct neighbour *neigh = from_timer(neigh, t, timer);
+	struct neighbour *neigh = timer_container_of(neigh, t, timer);
 	unsigned int state;
 	int notify = 0;
 
@@ -1568,7 +1517,7 @@ out:
 	return rc;
 out_kfree_skb:
 	rc = -EINVAL;
-	kfree_skb(skb);
+	kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_HH_FILLFAIL);
 	goto out;
 }
 EXPORT_SYMBOL(neigh_resolve_output);
@@ -1592,7 +1541,7 @@ int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb)
 		err = dev_queue_xmit(skb);
 	else {
 		err = -EINVAL;
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_HH_FILLFAIL);
 	}
 	return err;
 }
@@ -1620,7 +1569,7 @@ static void neigh_managed_work(struct work_struct *work)
 
 static void neigh_proxy_process(struct timer_list *t)
 {
-	struct neigh_table *tbl = from_timer(tbl, t, proxy_timer);
+	struct neigh_table *tbl = timer_container_of(tbl, t, proxy_timer);
 	long sched_next = 0;
 	unsigned long now = jiffies;
 	struct sk_buff *skb, *n;
@@ -1648,7 +1597,7 @@ static void neigh_proxy_process(struct timer_list *t)
 		} else if (!sched_next || tdif < sched_next)
 			sched_next = tdif;
 	}
-	del_timer(&tbl->proxy_timer);
+	timer_delete(&tbl->proxy_timer);
 	if (sched_next)
 		mod_timer(&tbl->proxy_timer, jiffies + sched_next);
 	spin_unlock(&tbl->proxy_queue.lock);
@@ -1679,7 +1628,7 @@ void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
 	NEIGH_CB(skb)->flags |= LOCALLY_ENQUEUED;
 
 	spin_lock(&tbl->proxy_queue.lock);
-	if (del_timer(&tbl->proxy_timer)) {
+	if (timer_delete(&tbl->proxy_timer)) {
 		if (time_before(tbl->proxy_timer.expires, sched_next))
 			sched_next = tbl->proxy_timer.expires;
 	}
@@ -1762,14 +1711,9 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
 }
 EXPORT_SYMBOL(neigh_parms_release);
 
-static void neigh_parms_destroy(struct neigh_parms *parms)
-{
-	kfree(parms);
-}
-
 static struct lock_class_key neigh_table_proxy_queue_class;
 
-static struct neigh_table *neigh_tables[NEIGH_NR_TABLES] __read_mostly;
+static struct neigh_table __rcu *neigh_tables[NEIGH_NR_TABLES] __read_mostly;
 
 void neigh_table_init(int index, struct neigh_table *tbl)
 {
@@ -1826,17 +1770,23 @@ void neigh_table_init(int index, struct neigh_table *tbl)
 	tbl->last_flush = now;
 	tbl->last_rand	= now + tbl->parms.reachable_time * 20;
 
-	neigh_tables[index] = tbl;
+	rcu_assign_pointer(neigh_tables[index], tbl);
 }
 EXPORT_SYMBOL(neigh_table_init);
 
+/*
+ * Only called from ndisc_cleanup(), which means this is dead code
+ * because we no longer can unload IPv6 module.
+ */
 int neigh_table_clear(int index, struct neigh_table *tbl)
 {
-	neigh_tables[index] = NULL;
+	RCU_INIT_POINTER(neigh_tables[index], NULL);
+	synchronize_rcu();
+
 	/* It is not clean... Fix it to unload IPv6 module safely */
 	cancel_delayed_work_sync(&tbl->managed_work);
 	cancel_delayed_work_sync(&tbl->gc_work);
-	del_timer_sync(&tbl->proxy_timer);
+	timer_delete_sync(&tbl->proxy_timer);
 	pneigh_queue_purge(&tbl->proxy_queue, NULL, tbl->family);
 	neigh_ifdown(tbl, NULL);
 	if (atomic_read(&tbl->entries))
@@ -1864,10 +1814,10 @@ static struct neigh_table *neigh_find_table(int family)
 
 	switch (family) {
 	case AF_INET:
-		tbl = neigh_tables[NEIGH_ARP_TABLE];
+		tbl = rcu_dereference_rtnl(neigh_tables[NEIGH_ARP_TABLE]);
 		break;
 	case AF_INET6:
-		tbl = neigh_tables[NEIGH_ND_TABLE];
+		tbl = rcu_dereference_rtnl(neigh_tables[NEIGH_ND_TABLE]);
 		break;
 	}
 
@@ -1949,7 +1899,7 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh,
 			     NETLINK_CB(skb).portid, extack);
 	write_lock_bh(&tbl->lock);
 	neigh_release(neigh);
-	neigh_remove_one(neigh, tbl);
+	neigh_remove_one(neigh);
 	write_unlock_bh(&tbl->lock);
 
 out:
@@ -2293,6 +2243,7 @@ static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = {
 static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
 	[NDTPA_IFINDEX]			= { .type = NLA_U32 },
 	[NDTPA_QUEUE_LEN]		= { .type = NLA_U32 },
+	[NDTPA_QUEUE_LENBYTES]		= { .type = NLA_U32 },
 	[NDTPA_PROXY_QLEN]		= { .type = NLA_U32 },
 	[NDTPA_APP_PROBES]		= { .type = NLA_U32 },
 	[NDTPA_UCAST_PROBES]		= { .type = NLA_U32 },
@@ -2331,7 +2282,7 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ndtmsg = nlmsg_data(nlh);
 
 	for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
-		tbl = neigh_tables[tidx];
+		tbl = rcu_dereference_rtnl(neigh_tables[tidx]);
 		if (!tbl)
 			continue;
 		if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
@@ -2479,12 +2430,12 @@ static int neightbl_valid_dump_info(const struct nlmsghdr *nlh,
 {
 	struct ndtmsg *ndtm;
 
-	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ndtm))) {
+	ndtm = nlmsg_payload(nlh, sizeof(*ndtm));
+	if (!ndtm) {
 		NL_SET_ERR_MSG(extack, "Invalid header for neighbor table dump request");
 		return -EINVAL;
 	}
 
-	ndtm = nlmsg_data(nlh);
 	if (ndtm->ndtm_pad1  || ndtm->ndtm_pad2) {
 		NL_SET_ERR_MSG(extack, "Invalid values in header for neighbor table dump request");
 		return -EINVAL;
@@ -2519,7 +2470,7 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 	for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
 		struct neigh_parms *p;
 
-		tbl = neigh_tables[tidx];
+		tbl = rcu_dereference_rtnl(neigh_tables[tidx]);
 		if (!tbl)
 			continue;
 
@@ -2674,7 +2625,7 @@ static bool neigh_master_filtered(struct net_device *dev, int master_idx)
 	if (!master_idx)
 		return false;
 
-	master = dev ? netdev_master_upper_dev_get(dev) : NULL;
+	master = dev ? netdev_master_upper_dev_get_rcu(dev) : NULL;
 
 	/* 0 is already used to denote NDA_MASTER wasn't passed, therefore need another
 	 * invalid value for ifindex to denote "no master".
@@ -2707,7 +2658,7 @@ static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
 {
 	struct net *net = sock_net(skb->sk);
 	struct neighbour *n;
-	int rc, h, s_h = cb->args[1];
+	int err = 0, h, s_h = cb->args[1];
 	int idx, s_idx = idx = cb->args[2];
 	struct neigh_hash_table *nht;
 	unsigned int flags = NLM_F_MULTI;
@@ -2715,37 +2666,31 @@ static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
 	if (filter->dev_idx || filter->master_idx)
 		flags |= NLM_F_DUMP_FILTERED;
 
-	rcu_read_lock();
 	nht = rcu_dereference(tbl->nht);
 
 	for (h = s_h; h < (1 << nht->hash_shift); h++) {
 		if (h > s_h)
 			s_idx = 0;
-		for (n = rcu_dereference(nht->hash_buckets[h]), idx = 0;
-		     n != NULL;
-		     n = rcu_dereference(n->next)) {
+		idx = 0;
+		neigh_for_each_in_bucket_rcu(n, &nht->hash_heads[h]) {
 			if (idx < s_idx || !net_eq(dev_net(n->dev), net))
 				goto next;
 			if (neigh_ifindex_filtered(n->dev, filter->dev_idx) ||
 			    neigh_master_filtered(n->dev, filter->master_idx))
 				goto next;
-			if (neigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
-					    cb->nlh->nlmsg_seq,
-					    RTM_NEWNEIGH,
-					    flags) < 0) {
-				rc = -1;
+			err = neigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
+					      cb->nlh->nlmsg_seq,
+					      RTM_NEWNEIGH, flags);
+			if (err < 0)
 				goto out;
-			}
 next:
 			idx++;
 		}
 	}
-	rc = skb->len;
 out:
-	rcu_read_unlock();
 	cb->args[1] = h;
 	cb->args[2] = idx;
-	return rc;
+	return err;
 }
 
 static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
@@ -2754,7 +2699,7 @@ static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
 {
 	struct pneigh_entry *n;
 	struct net *net = sock_net(skb->sk);
-	int rc, h, s_h = cb->args[3];
+	int err = 0, h, s_h = cb->args[3];
 	int idx, s_idx = idx = cb->args[4];
 	unsigned int flags = NLM_F_MULTI;
 
@@ -2772,11 +2717,11 @@ static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
 			if (neigh_ifindex_filtered(n->dev, filter->dev_idx) ||
 			    neigh_master_filtered(n->dev, filter->master_idx))
 				goto next;
-			if (pneigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
-					    cb->nlh->nlmsg_seq,
-					    RTM_NEWNEIGH, flags, tbl) < 0) {
+			err = pneigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
+					       cb->nlh->nlmsg_seq,
+					       RTM_NEWNEIGH, flags, tbl);
+			if (err < 0) {
 				read_unlock_bh(&tbl->lock);
-				rc = -1;
 				goto out;
 			}
 		next:
@@ -2785,12 +2730,10 @@ static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
 	}
 
 	read_unlock_bh(&tbl->lock);
-	rc = skb->len;
 out:
 	cb->args[3] = h;
 	cb->args[4] = idx;
-	return rc;
-
+	return err;
 }
 
 static int neigh_valid_dump_req(const struct nlmsghdr *nlh,
@@ -2804,12 +2747,12 @@ static int neigh_valid_dump_req(const struct nlmsghdr *nlh,
 	if (strict_check) {
 		struct ndmsg *ndm;
 
-		if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ndm))) {
+		ndm = nlmsg_payload(nlh, sizeof(*ndm));
+		if (!ndm) {
 			NL_SET_ERR_MSG(extack, "Invalid header for neighbor dump request");
 			return -EINVAL;
 		}
 
-		ndm = nlmsg_data(nlh);
 		if (ndm->ndm_pad1  || ndm->ndm_pad2  || ndm->ndm_ifindex ||
 		    ndm->ndm_state || ndm->ndm_type) {
 			NL_SET_ERR_MSG(extack, "Invalid values in header for neighbor dump request");
@@ -2875,11 +2818,13 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 	err = neigh_valid_dump_req(nlh, cb->strict_check, &filter, cb->extack);
 	if (err < 0 && cb->strict_check)
 		return err;
+	err = 0;
 
 	s_t = cb->args[0];
 
+	rcu_read_lock();
 	for (t = 0; t < NEIGH_NR_TABLES; t++) {
-		tbl = neigh_tables[t];
+		tbl = rcu_dereference(neigh_tables[t]);
 
 		if (!tbl)
 			continue;
@@ -2895,9 +2840,10 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 		if (err < 0)
 			break;
 	}
+	rcu_read_unlock();
 
 	cb->args[0] = t;
-	return skb->len;
+	return err;
 }
 
 static int neigh_valid_get_req(const struct nlmsghdr *nlh,
@@ -2909,12 +2855,12 @@ static int neigh_valid_get_req(const struct nlmsghdr *nlh,
 	struct ndmsg *ndm;
 	int err, i;
 
-	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ndm))) {
+	ndm = nlmsg_payload(nlh, sizeof(*ndm));
+	if (!ndm) {
 		NL_SET_ERR_MSG(extack, "Invalid header for neighbor get request");
 		return -EINVAL;
 	}
 
-	ndm = nlmsg_data(nlh);
 	if (ndm->ndm_pad1  || ndm->ndm_pad2  || ndm->ndm_state ||
 	    ndm->ndm_type) {
 		NL_SET_ERR_MSG(extack, "Invalid values in header for neighbor get request");
@@ -3094,9 +3040,7 @@ void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void
 	for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
 		struct neighbour *n;
 
-		for (n = rcu_dereference(nht->hash_buckets[chain]);
-		     n != NULL;
-		     n = rcu_dereference(n->next))
+		neigh_for_each_in_bucket(n, &nht->hash_heads[chain])
 			cb(n, cookie);
 	}
 	read_unlock_bh(&tbl->lock);
@@ -3108,29 +3052,25 @@ EXPORT_SYMBOL(neigh_for_each);
 void __neigh_for_each_release(struct neigh_table *tbl,
 			      int (*cb)(struct neighbour *))
 {
-	int chain;
 	struct neigh_hash_table *nht;
+	int chain;
 
 	nht = rcu_dereference_protected(tbl->nht,
 					lockdep_is_held(&tbl->lock));
 	for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
+		struct hlist_node *tmp;
 		struct neighbour *n;
-		struct neighbour __rcu **np;
 
-		np = &nht->hash_buckets[chain];
-		while ((n = rcu_dereference_protected(*np,
-					lockdep_is_held(&tbl->lock))) != NULL) {
+		neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[chain]) {
 			int release;
 
 			write_lock(&n->lock);
 			release = cb(n);
 			if (release) {
-				rcu_assign_pointer(*np,
-					rcu_dereference_protected(n->next,
-						lockdep_is_held(&tbl->lock)));
+				hlist_del_rcu(&n->hash);
+				hlist_del_rcu(&n->dev_list);
 				neigh_mark_dead(n);
-			} else
-				np = &n->next;
+			}
 			write_unlock(&n->lock);
 			if (release)
 				neigh_cleanup_and_release(n);
@@ -3143,14 +3083,15 @@ int neigh_xmit(int index, struct net_device *dev,
 	       const void *addr, struct sk_buff *skb)
 {
 	int err = -EAFNOSUPPORT;
+
 	if (likely(index < NEIGH_NR_TABLES)) {
 		struct neigh_table *tbl;
 		struct neighbour *neigh;
 
-		tbl = neigh_tables[index];
-		if (!tbl)
-			goto out;
 		rcu_read_lock();
+		tbl = rcu_dereference(neigh_tables[index]);
+		if (!tbl)
+			goto out_unlock;
 		if (index == NEIGH_ARP_TABLE) {
 			u32 key = *((u32 *)addr);
 
@@ -3166,6 +3107,7 @@ int neigh_xmit(int index, struct net_device *dev,
 			goto out_kfree_skb;
 		}
 		err = READ_ONCE(neigh->output)(neigh, skb);
+out_unlock:
 		rcu_read_unlock();
 	}
 	else if (index == NEIGH_LINK_TABLE) {
@@ -3185,43 +3127,53 @@ EXPORT_SYMBOL(neigh_xmit);
 
 #ifdef CONFIG_PROC_FS
 
-static struct neighbour *neigh_get_first(struct seq_file *seq)
+static struct neighbour *neigh_get_valid(struct seq_file *seq,
+					 struct neighbour *n,
+					 loff_t *pos)
 {
 	struct neigh_seq_state *state = seq->private;
 	struct net *net = seq_file_net(seq);
+
+	if (!net_eq(dev_net(n->dev), net))
+		return NULL;
+
+	if (state->neigh_sub_iter) {
+		loff_t fakep = 0;
+		void *v;
+
+		v = state->neigh_sub_iter(state, n, pos ? pos : &fakep);
+		if (!v)
+			return NULL;
+		if (pos)
+			return v;
+	}
+
+	if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
+		return n;
+
+	if (READ_ONCE(n->nud_state) & ~NUD_NOARP)
+		return n;
+
+	return NULL;
+}
+
+static struct neighbour *neigh_get_first(struct seq_file *seq)
+{
+	struct neigh_seq_state *state = seq->private;
 	struct neigh_hash_table *nht = state->nht;
-	struct neighbour *n = NULL;
-	int bucket;
+	struct neighbour *n, *tmp;
 
 	state->flags &= ~NEIGH_SEQ_IS_PNEIGH;
-	for (bucket = 0; bucket < (1 << nht->hash_shift); bucket++) {
-		n = rcu_dereference(nht->hash_buckets[bucket]);
 
-		while (n) {
-			if (!net_eq(dev_net(n->dev), net))
-				goto next;
-			if (state->neigh_sub_iter) {
-				loff_t fakep = 0;
-				void *v;
-
-				v = state->neigh_sub_iter(state, n, &fakep);
-				if (!v)
-					goto next;
-			}
-			if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
-				break;
-			if (READ_ONCE(n->nud_state) & ~NUD_NOARP)
-				break;
-next:
-			n = rcu_dereference(n->next);
+	while (++state->bucket < (1 << nht->hash_shift)) {
+		neigh_for_each_in_bucket(n, &nht->hash_heads[state->bucket]) {
+			tmp = neigh_get_valid(seq, n, NULL);
+			if (tmp)
+				return tmp;
 		}
-
-		if (n)
-			break;
 	}
-	state->bucket = bucket;
 
-	return n;
+	return NULL;
 }
 
 static struct neighbour *neigh_get_next(struct seq_file *seq,
@@ -3229,46 +3181,28 @@ static struct neighbour *neigh_get_next(struct seq_file *seq,
 					loff_t *pos)
 {
 	struct neigh_seq_state *state = seq->private;
-	struct net *net = seq_file_net(seq);
-	struct neigh_hash_table *nht = state->nht;
+	struct neighbour *tmp;
 
 	if (state->neigh_sub_iter) {
 		void *v = state->neigh_sub_iter(state, n, pos);
+
 		if (v)
 			return n;
 	}
-	n = rcu_dereference(n->next);
 
-	while (1) {
-		while (n) {
-			if (!net_eq(dev_net(n->dev), net))
-				goto next;
-			if (state->neigh_sub_iter) {
-				void *v = state->neigh_sub_iter(state, n, pos);
-				if (v)
-					return n;
-				goto next;
-			}
-			if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
-				break;
-
-			if (READ_ONCE(n->nud_state) & ~NUD_NOARP)
-				break;
-next:
-			n = rcu_dereference(n->next);
+	hlist_for_each_entry_continue(n, hash) {
+		tmp = neigh_get_valid(seq, n, pos);
+		if (tmp) {
+			n = tmp;
+			goto out;
 		}
-
-		if (n)
-			break;
-
-		if (++state->bucket >= (1 << nht->hash_shift))
-			break;
-
-		n = rcu_dereference(nht->hash_buckets[state->bucket]);
 	}
 
+	n = neigh_get_first(seq);
+out:
 	if (n && pos)
 		--(*pos);
+
 	return n;
 }
 
@@ -3371,7 +3305,7 @@ void *neigh_seq_start(struct seq_file *seq, loff_t *pos, struct neigh_table *tbl
 	struct neigh_seq_state *state = seq->private;
 
 	state->tbl = tbl;
-	state->bucket = 0;
+	state->bucket = -1;
 	state->flags = (neigh_seq_flags & ~NEIGH_SEQ_IS_PNEIGH);
 
 	rcu_read_lock();
@@ -3507,10 +3441,12 @@ static const struct seq_operations neigh_stat_seq_ops = {
 static void __neigh_notify(struct neighbour *n, int type, int flags,
 			   u32 pid)
 {
-	struct net *net = dev_net(n->dev);
 	struct sk_buff *skb;
 	int err = -ENOBUFS;
+	struct net *net;
 
+	rcu_read_lock();
+	net = dev_net_rcu(n->dev);
 	skb = nlmsg_new(neigh_nlmsg_size(), GFP_ATOMIC);
 	if (skb == NULL)
 		goto errout;
@@ -3523,10 +3459,11 @@ static void __neigh_notify(struct neighbour *n, int type, int flags,
 		goto errout;
 	}
 	rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
-	return;
+	goto out;
 errout:
-	if (err < 0)
-		rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
+	rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
+out:
+	rcu_read_unlock();
 }
 
 void neigh_app_ns(struct neighbour *n)
@@ -3538,7 +3475,7 @@ EXPORT_SYMBOL(neigh_app_ns);
 #ifdef CONFIG_SYSCTL
 static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
 
-static int proc_unres_qlen(struct ctl_table *ctl, int write,
+static int proc_unres_qlen(const struct ctl_table *ctl, int write,
 			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int size, ret;
@@ -3573,7 +3510,7 @@ static void neigh_copy_dflt_parms(struct net *net, struct neigh_parms *p,
 	rcu_read_unlock();
 }
 
-static void neigh_proc_update(struct ctl_table *ctl, int write)
+static void neigh_proc_update(const struct ctl_table *ctl, int write)
 {
 	struct net_device *dev = ctl->extra1;
 	struct neigh_parms *p = ctl->extra2;
@@ -3590,7 +3527,7 @@ static void neigh_proc_update(struct ctl_table *ctl, int write)
 		neigh_copy_dflt_parms(net, p, index);
 }
 
-static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
+static int neigh_proc_dointvec_zero_intmax(const struct ctl_table *ctl, int write,
 					   void *buffer, size_t *lenp,
 					   loff_t *ppos)
 {
@@ -3605,7 +3542,7 @@ static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
 	return ret;
 }
 
-static int neigh_proc_dointvec_ms_jiffies_positive(struct ctl_table *ctl, int write,
+static int neigh_proc_dointvec_ms_jiffies_positive(const struct ctl_table *ctl, int write,
 						   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table tmp = *ctl;
@@ -3621,7 +3558,7 @@ static int neigh_proc_dointvec_ms_jiffies_positive(struct ctl_table *ctl, int wr
 	return ret;
 }
 
-int neigh_proc_dointvec(struct ctl_table *ctl, int write, void *buffer,
+int neigh_proc_dointvec(const struct ctl_table *ctl, int write, void *buffer,
 			size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
@@ -3631,7 +3568,7 @@ int neigh_proc_dointvec(struct ctl_table *ctl, int write, void *buffer,
 }
 EXPORT_SYMBOL(neigh_proc_dointvec);
 
-int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, void *buffer,
+int neigh_proc_dointvec_jiffies(const struct ctl_table *ctl, int write, void *buffer,
 				size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
@@ -3641,7 +3578,7 @@ int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, void *buffer,
 }
 EXPORT_SYMBOL(neigh_proc_dointvec_jiffies);
 
-static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
+static int neigh_proc_dointvec_userhz_jiffies(const struct ctl_table *ctl, int write,
 					      void *buffer, size_t *lenp,
 					      loff_t *ppos)
 {
@@ -3651,7 +3588,7 @@ static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
 	return ret;
 }
 
-int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
+int neigh_proc_dointvec_ms_jiffies(const struct ctl_table *ctl, int write,
 				   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
@@ -3661,7 +3598,7 @@ int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 }
 EXPORT_SYMBOL(neigh_proc_dointvec_ms_jiffies);
 
-static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
+static int neigh_proc_dointvec_unres_qlen(const struct ctl_table *ctl, int write,
 					  void *buffer, size_t *lenp,
 					  loff_t *ppos)
 {
@@ -3671,7 +3608,7 @@ static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
 	return ret;
 }
 
-static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
+static int neigh_proc_base_reachable_time(const struct ctl_table *ctl, int write,
 					  void *buffer, size_t *lenp,
 					  loff_t *ppos)
 {
@@ -3728,7 +3665,7 @@ static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
 
 static struct neigh_sysctl_table {
 	struct ctl_table_header *sysctl_header;
-	struct ctl_table neigh_vars[NEIGH_VAR_MAX + 1];
+	struct ctl_table neigh_vars[NEIGH_VAR_MAX];
 } neigh_sysctl_template __read_mostly = {
 	.neigh_vars = {
 		NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_PROBES, "mcast_solicit"),
@@ -3779,7 +3716,6 @@ static struct neigh_sysctl_table {
 			.extra2		= SYSCTL_INT_MAX,
 			.proc_handler	= proc_dointvec_minmax,
 		},
-		{},
 	},
 };
 
@@ -3807,8 +3743,6 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 	if (dev) {
 		dev_name_source = dev->name;
 		/* Terminate the table early */
-		memset(&t->neigh_vars[NEIGH_VAR_GC_INTERVAL], 0,
-		       sizeof(t->neigh_vars[NEIGH_VAR_GC_INTERVAL]));
 		neigh_vars_size = NEIGH_VAR_BASE_REACHABLE_TIME_MS + 1;
 	} else {
 		struct neigh_table *tbl = p->tbl;
@@ -3885,16 +3819,18 @@ EXPORT_SYMBOL(neigh_sysctl_unregister);
 
 #endif	/* CONFIG_SYSCTL */
 
+static const struct rtnl_msg_handler neigh_rtnl_msg_handlers[] __initconst = {
+	{.msgtype = RTM_NEWNEIGH, .doit = neigh_add},
+	{.msgtype = RTM_DELNEIGH, .doit = neigh_delete},
+	{.msgtype = RTM_GETNEIGH, .doit = neigh_get, .dumpit = neigh_dump_info,
+	 .flags = RTNL_FLAG_DUMP_UNLOCKED},
+	{.msgtype = RTM_GETNEIGHTBL, .dumpit = neightbl_dump_info},
+	{.msgtype = RTM_SETNEIGHTBL, .doit = neightbl_set},
+};
+
 static int __init neigh_init(void)
 {
-	rtnl_register(PF_UNSPEC, RTM_NEWNEIGH, neigh_add, NULL, 0);
-	rtnl_register(PF_UNSPEC, RTM_DELNEIGH, neigh_delete, NULL, 0);
-	rtnl_register(PF_UNSPEC, RTM_GETNEIGH, neigh_get, neigh_dump_info, 0);
-
-	rtnl_register(PF_UNSPEC, RTM_GETNEIGHTBL, NULL, neightbl_dump_info,
-		      0);
-	rtnl_register(PF_UNSPEC, RTM_SETNEIGHTBL, neightbl_set, NULL, 0);
-
+	rtnl_register_many(neigh_rtnl_msg_handlers);
 	return 0;
 }