1 files changed, 373 insertions, 75 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 5fa32c064baf..fa384f775f1a 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -118,21 +118,77 @@ 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_update_gc_list(struct neighbour *n)
+{
+	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 or if neighbor
+	 * is externally learned; otherwise entry should be on the gc list
+	 */
+	exempt_from_gc = n->nud_state & NUD_PERMANENT ||
+			 n->flags & NTF_EXT_LEARNED;
+	on_gc_list = !list_empty(&n->gc_list);
+
+	if (exempt_from_gc && on_gc_list) {
+		list_del_init(&n->gc_list);
+		atomic_dec(&n->tbl->gc_entries);
+	} 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);
+	}
+
+	write_unlock(&n->lock);
+	write_unlock_bh(&n->tbl->lock);
+}
 
-static bool neigh_del(struct neighbour *n, __u8 state, __u8 flags,
-		      struct neighbour __rcu **np, struct neigh_table *tbl)
+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 rc;
+
+	ndm_flags = (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0;
+	if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) {
+		if (ndm_flags & NTF_EXT_LEARNED)
+			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,
+		      struct neigh_table *tbl)
 {
 	bool retval = false;
 
 	write_lock(&n->lock);
-	if (refcount_read(&n->refcnt) == 1 && !(n->nud_state & state) &&
-	    !(n->flags & flags)) {
+	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);
-		n->dead = 1;
+		neigh_mark_dead(n);
 		retval = true;
 	}
 	write_unlock(&n->lock);
@@ -158,7 +214,7 @@ bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl)
 	while ((n = rcu_dereference_protected(*np,
 					      lockdep_is_held(&tbl->lock)))) {
 		if (n == ndel)
-			return neigh_del(n, 0, 0, np, tbl);
+			return neigh_del(n, np, tbl);
 		np = &n->next;
 	}
 	return false;
@@ -166,32 +222,29 @@ 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;
+	struct neighbour *n, *tmp;
 	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 == NUD_FAILED) ||
+			    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 +313,7 @@ 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 +373,18 @@ 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 exempt_from_gc)
 {
 	struct neighbour *n = NULL;
 	unsigned long now = jiffies;
 	int entries;
 
-	entries = atomic_inc_return(&tbl->entries) - 1;
+	if (exempt_from_gc)
+		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 +397,7 @@ 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 +416,15 @@ 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 (!exempt_from_gc)
+		atomic_dec(&tbl->gc_entries);
 	goto out;
 }
 
@@ -505,13 +567,15 @@ 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 exempt_from_gc, bool want_ref)
 {
+	struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, exempt_from_gc);
 	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 +638,9 @@ struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
 	}
 
 	n->dead = 0;
+	if (!exempt_from_gc)
+		list_add_tail(&n->gc_list, &n->tbl->gc_list);
+
 	if (want_ref)
 		neigh_hold(n);
 	rcu_assign_pointer(n->next,
@@ -591,6 +658,12 @@ 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)
@@ -652,6 +725,7 @@ struct pneigh_entry * pneigh_lookup(struct neigh_table *tbl,
 	if (!n)
 		goto out;
 
+	n->protocol = 0;
 	write_pnet(&n->net, net);
 	memcpy(n->key, pkey, key_len);
 	n->dev = dev;
@@ -854,7 +928,7 @@ 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;
@@ -1137,9 +1211,11 @@ 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)
 {
+	bool ext_learn_change = false;
 	u8 old;
 	int err;
 	int notify = 0;
@@ -1155,10 +1231,12 @@ 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);
+	ext_learn_change = neigh_update_ext_learned(neigh, flags, &notify);
 
 	if (!(new & NUD_VALID)) {
 		neigh_del_timer(neigh);
@@ -1193,8 +1271,10 @@ 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;
 	}
 
@@ -1302,11 +1382,20 @@ out:
 		neigh_update_is_router(neigh, flags, &notify);
 	write_unlock_bh(&neigh->lock);
 
+	if (((new ^ old) & NUD_PERMANENT) || ext_learn_change)
+		neigh_update_gc_list(neigh);
+
 	if (notify)
 		neigh_update_notify(neigh, nlmsg_pid);
 
 	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 +1660,7 @@ 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);
@@ -1662,6 +1752,19 @@ static struct neigh_table *neigh_find_table(int family)
 	return tbl;
 }
 
+const struct nla_policy nda_policy[NDA_MAX+1] = {
+	[NDA_DST]		= { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
+	[NDA_LLADDR]		= { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
+	[NDA_CACHEINFO]		= { .len = sizeof(struct nda_cacheinfo) },
+	[NDA_PROBES]		= { .type = NLA_U32 },
+	[NDA_VLAN]		= { .type = NLA_U16 },
+	[NDA_PORT]		= { .type = NLA_U16 },
+	[NDA_VNI]		= { .type = NLA_U32 },
+	[NDA_IFINDEX]		= { .type = NLA_U32 },
+	[NDA_MASTER]		= { .type = NLA_U32 },
+	[NDA_PROTOCOL]		= { .type = NLA_U8 },
+};
+
 static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh,
 			struct netlink_ext_ack *extack)
 {
@@ -1678,8 +1781,10 @@ 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 +1799,10 @@ 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 +1818,9 @@ 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);
@@ -1736,16 +1842,19 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 	struct net_device *dev = NULL;
 	struct neighbour *neigh;
 	void *dst, *lladdr;
+	u8 protocol = 0;
 	int err;
 
 	ASSERT_RTNL();
-	err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, NULL, extack);
+	err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, nda_policy, extack);
 	if (err < 0)
 		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) {
@@ -1755,19 +1864,27 @@ 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;
 
+	if (tb[NDA_PROTOCOL])
+		protocol = nla_get_u8(tb[NDA_PROTOCOL]);
+
 	if (ndm->ndm_flags & NTF_PROXY) {
 		struct pneigh_entry *pn;
 
@@ -1775,22 +1892,30 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 		pn = pneigh_lookup(tbl, net, dst, dev, 1);
 		if (pn) {
 			pn->flags = ndm->ndm_flags;
+			if (protocol)
+				pn->protocol = protocol;
 			err = 0;
 		}
 		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) {
+		bool exempt_from_gc;
+
 		if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
 			err = -ENOENT;
 			goto out;
 		}
 
-		neigh = __neigh_lookup_errno(tbl, dst, dev);
+		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;
@@ -1817,8 +1942,12 @@ 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);
+
+	if (protocol)
+		neigh->protocol = protocol;
+
 	neigh_release(neigh);
 
 out:
@@ -2312,6 +2441,9 @@ static int neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,
 	    nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
 		goto nla_put_failure;
 
+	if (neigh->protocol && nla_put_u8(skb, NDA_PROTOCOL, neigh->protocol))
+		goto nla_put_failure;
+
 	nlmsg_end(skb, nlh);
 	return 0;
 
@@ -2343,6 +2475,9 @@ static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
 	if (nla_put(skb, NDA_DST, tbl->key_len, pn->key))
 		goto nla_put_failure;
 
+	if (pn->protocol && nla_put_u8(skb, NDA_PROTOCOL, pn->protocol))
+		goto nla_put_failure;
+
 	nlmsg_end(skb, nlh);
 	return 0;
 
@@ -2505,10 +2640,10 @@ static int neigh_valid_dump_req(const struct nlmsghdr *nlh,
 		}
 
 		err = nlmsg_parse_strict(nlh, sizeof(struct ndmsg), tb, NDA_MAX,
-					 NULL, extack);
+					 nda_policy, extack);
 	} else {
 		err = nlmsg_parse(nlh, sizeof(struct ndmsg), tb, NDA_MAX,
-				  NULL, extack);
+				  nda_policy, extack);
 	}
 	if (err < 0)
 		return err;
@@ -2520,17 +2655,9 @@ static int neigh_valid_dump_req(const struct nlmsghdr *nlh,
 		/* all new attributes should require strict_check */
 		switch (i) {
 		case NDA_IFINDEX:
-			if (nla_len(tb[i]) != sizeof(u32)) {
-				NL_SET_ERR_MSG(extack, "Invalid IFINDEX attribute in neighbor dump request");
-				return -EINVAL;
-			}
 			filter->dev_idx = nla_get_u32(tb[i]);
 			break;
 		case NDA_MASTER:
-			if (nla_len(tb[i]) != sizeof(u32)) {
-				NL_SET_ERR_MSG(extack, "Invalid MASTER attribute in neighbor dump request");
-				return -EINVAL;
-			}
 			filter->master_idx = nla_get_u32(tb[i]);
 			break;
 		default:
@@ -2590,6 +2717,186 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
+static int neigh_valid_get_req(const struct nlmsghdr *nlh,
+			       struct neigh_table **tbl,
+			       void **dst, int *dev_idx, u8 *ndm_flags,
+			       struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[NDA_MAX + 1];
+	struct ndmsg *ndm;
+	int err, i;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*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");
+		return -EINVAL;
+	}
+
+	if (ndm->ndm_flags & ~NTF_PROXY) {
+		NL_SET_ERR_MSG(extack, "Invalid flags in header for neighbor get request");
+		return -EINVAL;
+	}
+
+	err = nlmsg_parse_strict(nlh, sizeof(struct ndmsg), tb, NDA_MAX,
+				 nda_policy, extack);
+	if (err < 0)
+		return err;
+
+	*ndm_flags = ndm->ndm_flags;
+	*dev_idx = ndm->ndm_ifindex;
+	*tbl = neigh_find_table(ndm->ndm_family);
+	if (*tbl == NULL) {
+		NL_SET_ERR_MSG(extack, "Unsupported family in header for neighbor get request");
+		return -EAFNOSUPPORT;
+	}
+
+	for (i = 0; i <= NDA_MAX; ++i) {
+		if (!tb[i])
+			continue;
+
+		switch (i) {
+		case NDA_DST:
+			if (nla_len(tb[i]) != (int)(*tbl)->key_len) {
+				NL_SET_ERR_MSG(extack, "Invalid network address in neighbor get request");
+				return -EINVAL;
+			}
+			*dst = nla_data(tb[i]);
+			break;
+		default:
+			NL_SET_ERR_MSG(extack, "Unsupported attribute in neighbor get request");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static inline size_t neigh_nlmsg_size(void)
+{
+	return NLMSG_ALIGN(sizeof(struct ndmsg))
+	       + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */
+	       + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */
+	       + nla_total_size(sizeof(struct nda_cacheinfo))
+	       + nla_total_size(4)  /* NDA_PROBES */
+	       + nla_total_size(1); /* NDA_PROTOCOL */
+}
+
+static int neigh_get_reply(struct net *net, struct neighbour *neigh,
+			   u32 pid, u32 seq)
+{
+	struct sk_buff *skb;
+	int err = 0;
+
+	skb = nlmsg_new(neigh_nlmsg_size(), GFP_KERNEL);
+	if (!skb)
+		return -ENOBUFS;
+
+	err = neigh_fill_info(skb, neigh, pid, seq, RTM_NEWNEIGH, 0);
+	if (err) {
+		kfree_skb(skb);
+		goto errout;
+	}
+
+	err = rtnl_unicast(skb, net, pid);
+errout:
+	return err;
+}
+
+static inline size_t pneigh_nlmsg_size(void)
+{
+	return NLMSG_ALIGN(sizeof(struct ndmsg))
+	       + nla_total_size(MAX_ADDR_LEN); /* NDA_DST */
+	       + nla_total_size(1); /* NDA_PROTOCOL */
+}
+
+static int pneigh_get_reply(struct net *net, struct pneigh_entry *neigh,
+			    u32 pid, u32 seq, struct neigh_table *tbl)
+{
+	struct sk_buff *skb;
+	int err = 0;
+
+	skb = nlmsg_new(pneigh_nlmsg_size(), GFP_KERNEL);
+	if (!skb)
+		return -ENOBUFS;
+
+	err = pneigh_fill_info(skb, neigh, pid, seq, RTM_NEWNEIGH, 0, tbl);
+	if (err) {
+		kfree_skb(skb);
+		goto errout;
+	}
+
+	err = rtnl_unicast(skb, net, pid);
+errout:
+	return err;
+}
+
+static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
+		     struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(in_skb->sk);
+	struct net_device *dev = NULL;
+	struct neigh_table *tbl = NULL;
+	struct neighbour *neigh;
+	void *dst = NULL;
+	u8 ndm_flags = 0;
+	int dev_idx = 0;
+	int err;
+
+	err = neigh_valid_get_req(nlh, &tbl, &dst, &dev_idx, &ndm_flags,
+				  extack);
+	if (err < 0)
+		return err;
+
+	if (dev_idx) {
+		dev = __dev_get_by_index(net, dev_idx);
+		if (!dev) {
+			NL_SET_ERR_MSG(extack, "Unknown device ifindex");
+			return -ENODEV;
+		}
+	}
+
+	if (!dst) {
+		NL_SET_ERR_MSG(extack, "Network address not specified");
+		return -EINVAL;
+	}
+
+	if (ndm_flags & NTF_PROXY) {
+		struct pneigh_entry *pn;
+
+		pn = pneigh_lookup(tbl, net, dst, dev, 0);
+		if (!pn) {
+			NL_SET_ERR_MSG(extack, "Proxy neighbour entry not found");
+			return -ENOENT;
+		}
+		return pneigh_get_reply(net, pn, NETLINK_CB(in_skb).portid,
+					nlh->nlmsg_seq, tbl);
+	}
+
+	if (!dev) {
+		NL_SET_ERR_MSG(extack, "No device specified");
+		return -EINVAL;
+	}
+
+	neigh = neigh_lookup(tbl, dst, dev);
+	if (!neigh) {
+		NL_SET_ERR_MSG(extack, "Neighbour entry not found");
+		return -ENOENT;
+	}
+
+	err = neigh_get_reply(net, neigh, NETLINK_CB(in_skb).portid,
+			      nlh->nlmsg_seq);
+
+	neigh_release(neigh);
+
+	return err;
+}
+
 void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie)
 {
 	int chain;
@@ -2636,7 +2943,7 @@ 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);
@@ -2997,15 +3304,6 @@ static const struct seq_operations neigh_stat_seq_ops = {
 };
 #endif /* CONFIG_PROC_FS */
 
-static inline size_t neigh_nlmsg_size(void)
-{
-	return NLMSG_ALIGN(sizeof(struct ndmsg))
-	       + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */
-	       + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */
-	       + nla_total_size(sizeof(struct nda_cacheinfo))
-	       + nla_total_size(4); /* NDA_PROBES */
-}
-
 static void __neigh_notify(struct neighbour *n, int type, int flags,
 			   u32 pid)
 {
@@ -3389,7 +3687,7 @@ 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, NULL, neigh_dump_info, 0);
+	rtnl_register(PF_UNSPEC, RTM_GETNEIGH, neigh_get, neigh_dump_info, 0);
 
 	rtnl_register(PF_UNSPEC, RTM_GETNEIGHTBL, NULL, neightbl_dump_info,
 		      0);