From 859bd2ef1fc1110a8031b967ee656c53a6260a76 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 11 Oct 2018 20:33:49 -0700 Subject: net: Evict neighbor entries on carrier down When a link's carrier goes down it could be a sign of the port changing networks. If the new network has overlapping addresses with the old one, then the kernel will continue trying to use neighbor entries established based on the old network until the entries finally age out - meaning a potentially long delay with communications not working. This patch evicts neighbor entries on carrier down with the exception of those marked permanent. Permanent entries are managed by userspace (either an admin or a routing daemon such as FRR). Signed-off-by: David Ahern Signed-off-by: David S. Miller --- net/core/neighbour.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) (limited to 'net/core/neighbour.c') diff --git a/net/core/neighbour.c b/net/core/neighbour.c index dc1389b8beb1..69c41cb3966d 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -232,7 +232,8 @@ static void pneigh_queue_purge(struct sk_buff_head *list) } } -static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev) +static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev, + bool skip_perm) { int i; struct neigh_hash_table *nht; @@ -250,6 +251,10 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *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))); @@ -285,21 +290,35 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev) void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev) { write_lock_bh(&tbl->lock); - neigh_flush_dev(tbl, dev); + neigh_flush_dev(tbl, dev, false); write_unlock_bh(&tbl->lock); } EXPORT_SYMBOL(neigh_changeaddr); -int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev) +static int __neigh_ifdown(struct neigh_table *tbl, struct net_device *dev, + bool skip_perm) { write_lock_bh(&tbl->lock); - neigh_flush_dev(tbl, dev); + neigh_flush_dev(tbl, dev, skip_perm); pneigh_ifdown_and_unlock(tbl, dev); del_timer_sync(&tbl->proxy_timer); pneigh_queue_purge(&tbl->proxy_queue); return 0; } + +int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev) +{ + __neigh_ifdown(tbl, dev, true); + return 0; +} +EXPORT_SYMBOL(neigh_carrier_down); + +int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev) +{ + __neigh_ifdown(tbl, dev, false); + return 0; +} EXPORT_SYMBOL(neigh_ifdown); static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device *dev) -- cgit v1.2.3-59-g8ed1b