From 5071034e4af709d6783b7d105dc296a5cc84739b Mon Sep 17 00:00:00 2001 From: Sowmini Varadhan Date: Fri, 2 Jun 2017 09:01:49 -0700 Subject: neigh: Really delete an arp/neigh entry on "ip neigh delete" or "arp -d" The command # arp -s 62.2.0.1 a:b:c:d:e:f dev eth2 adds an entry like the following (listed by "arp -an") ? (62.2.0.1) at 0a:0b:0c:0d:0e:0f [ether] PERM on eth2 but the symmetric deletion command # arp -i eth2 -d 62.2.0.1 does not remove the PERM entry from the table, and instead leaves behind ? (62.2.0.1) at on eth2 The reason is that there is a refcnt of 1 for the arp_tbl itself (neigh_alloc starts off the entry with a refcnt of 1), thus the neigh_release() call from arp_invalidate() will (at best) just decrement the ref to 1, but will never actually free it from the table. To fix this, we need to do something like neigh_forced_gc: if the refcnt is 1 (i.e., on the table's ref), remove the entry from the table and free it. This patch refactors and shares common code between neigh_forced_gc and the newly added neigh_remove_one. A similar issue exists for IPv6 Neighbor Cache entries, and is fixed in a similar manner by this patch. Signed-off-by: Sowmini Varadhan Reviewed-by: Julian Anastasov Signed-off-by: David S. Miller --- include/net/neighbour.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/neighbour.h') diff --git a/include/net/neighbour.h b/include/net/neighbour.h index e4dd3a214034..639b67564a7d 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -317,6 +317,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb); int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags, u32 nlmsg_pid); void __neigh_set_probe_once(struct neighbour *neigh); +bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl); void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev); int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev); int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb); -- cgit v1.2.3-59-g8ed1b