6.1-stable review patch. If anyone has any objections, please let me know.
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From: Nicolas Escande nico.escande@gmail.com
[ Upstream commit c7d78566bbd30544a0618a6ffbc97bc0ddac7035 ]
As discussesd before in [0] proxy entries (which are more configuration than runtime data) should stay when the link (carrier) goes does down. This is what happens for regular neighbour entries.
So lets fix this by: - storing in proxy entries the fact that it was added as NUD_PERMANENT - not removing NUD_PERMANENT proxy entries when the carrier goes down (same as how it's done in neigh_flush_dev() for regular neigh entries)
[0]: https://lore.kernel.org/netdev/c584ef7e-6897-01f3-5b80-12b53f7b4bf4@kernel.o...
Signed-off-by: Nicolas Escande nico.escande@gmail.com Reviewed-by: Kuniyuki Iwashima kuniyu@google.com Link: https://patch.msgid.link/20250617141334.3724863-1-nico.escande@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/neighbour.h | 1 + net/core/neighbour.c | 12 +++++++++--- 2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/include/net/neighbour.h b/include/net/neighbour.h index ccc4a0f8b4ad..93aecfaa7628 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -180,6 +180,7 @@ struct pneigh_entry { netdevice_tracker dev_tracker; u32 flags; u8 protocol; + bool permanent; u32 key[]; };
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index bcc3950638b9..92dc1f1788de 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -55,7 +55,8 @@ static void __neigh_notify(struct neighbour *n, int type, int flags, u32 pid); static void neigh_update_notify(struct neighbour *neigh, u32 nlmsg_pid); static int pneigh_ifdown_and_unlock(struct neigh_table *tbl, - struct net_device *dev); + struct net_device *dev, + bool skip_perm);
#ifdef CONFIG_PROC_FS static const struct seq_operations neigh_stat_seq_ops; @@ -444,7 +445,7 @@ static int __neigh_ifdown(struct neigh_table *tbl, struct net_device *dev, { write_lock_bh(&tbl->lock); neigh_flush_dev(tbl, dev, skip_perm); - pneigh_ifdown_and_unlock(tbl, dev); + pneigh_ifdown_and_unlock(tbl, dev, skip_perm); pneigh_queue_purge(&tbl->proxy_queue, dev ? dev_net(dev) : NULL, tbl->family); if (skb_queue_empty_lockless(&tbl->proxy_queue)) @@ -845,7 +846,8 @@ int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *pkey, }
static int pneigh_ifdown_and_unlock(struct neigh_table *tbl, - struct net_device *dev) + struct net_device *dev, + bool skip_perm) { struct pneigh_entry *n, **np, *freelist = NULL; u32 h; @@ -853,12 +855,15 @@ static int pneigh_ifdown_and_unlock(struct neigh_table *tbl, for (h = 0; h <= PNEIGH_HASHMASK; h++) { np = &tbl->phash_buckets[h]; while ((n = *np) != NULL) { + if (skip_perm && n->permanent) + goto skip; if (!dev || n->dev == dev) { *np = n->next; n->next = freelist; freelist = n; continue; } +skip: np = &n->next; } } @@ -2023,6 +2028,7 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, pn = pneigh_lookup(tbl, net, dst, dev, 1); if (pn) { pn->flags = ndm_flags; + pn->permanent = !!(ndm->ndm_state & NUD_PERMANENT); if (protocol) pn->protocol = protocol; err = 0;