From e997f8a20a57cae16ed0c7a2bff6d3ab75f58123 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Tue, 11 Dec 2018 18:57:25 -0700 Subject: [PATCH] neighbor: Remove externally learned entries from gc_list Externally learned entries are similar to PERMANENT entries in the sense they are managed by userspace and can not be garbage collected. As such remove them from the gc_list, remove the flags check from neigh_forced_gc and skip threshold checks in neigh_alloc. As with PERMANENT entries, this allows unlimited number of NTF_EXT_LEARNED entries. Signed-off-by: David Ahern Signed-off-by: David S. Miller --- net/core/neighbour.c | 49 +++++++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 21 deletions(-) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 2401040f799b..42b413774370 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -129,21 +129,22 @@ static void neigh_mark_dead(struct neighbour *n) static void neigh_update_gc_list(struct neighbour *n) { - bool on_gc_list, new_is_perm; + 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; - * add to the gc list if new state is not permanent + /* remove from the gc list if new state is permanent or if neighbor + * is externally learned; otherwise entry should be on the gc list */ - new_is_perm = n->nud_state & NUD_PERMANENT; + exempt_from_gc = n->nud_state & NUD_PERMANENT || + n->flags & NTF_EXT_LEARNED; on_gc_list = !list_empty(&n->gc_list); - if (new_is_perm && on_gc_list) { + if (exempt_from_gc && on_gc_list) { list_del_init(&n->gc_list); atomic_dec(&n->tbl->gc_entries); - } else if (!new_is_perm && !on_gc_list) { + } 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); @@ -153,13 +154,14 @@ static void neigh_update_gc_list(struct neighbour *n) write_unlock_bh(&n->tbl->lock); } -static void neigh_update_ext_learned(struct neighbour *neigh, u32 flags, +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; + return rc; ndm_flags = (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0; if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) { @@ -167,8 +169,11 @@ static void neigh_update_ext_learned(struct neighbour *neigh, u32 flags, 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, @@ -219,7 +224,6 @@ 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; - u8 flags = NTF_EXT_LEARNED; struct neighbour *n, *tmp; int shrunk = 0; @@ -233,7 +237,7 @@ static int neigh_forced_gc(struct neigh_table *tbl) write_lock(&n->lock); if ((n->nud_state == NUD_FAILED) || - (!(n->flags & flags) && time_after(tref, n->updated))) + time_after(tref, n->updated)) remove = true; write_unlock(&n->lock); @@ -371,13 +375,13 @@ EXPORT_SYMBOL(neigh_ifdown); static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device *dev, - bool permanent) + bool exempt_from_gc) { struct neighbour *n = NULL; unsigned long now = jiffies; int entries; - if (permanent) + if (exempt_from_gc) goto do_alloc; entries = atomic_inc_return(&tbl->gc_entries) - 1; @@ -419,7 +423,7 @@ out: return n; out_entries: - if (!permanent) + if (!exempt_from_gc) atomic_dec(&tbl->gc_entries); goto out; } @@ -566,9 +570,9 @@ EXPORT_SYMBOL(neigh_lookup_nodev); static struct neighbour *___neigh_create(struct neigh_table *tbl, const void *pkey, struct net_device *dev, - bool permanent, bool want_ref) + bool exempt_from_gc, bool want_ref) { - struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, permanent); + struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, exempt_from_gc); u32 hash_val; unsigned int key_len = tbl->key_len; int error; @@ -634,7 +638,7 @@ static struct neighbour *___neigh_create(struct neigh_table *tbl, } n->dead = 0; - if (!permanent) + if (!exempt_from_gc) list_add_tail(&n->gc_list, &n->tbl->gc_list); if (want_ref) @@ -1210,6 +1214,7 @@ 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; @@ -1230,7 +1235,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, goto out; } - neigh_update_ext_learned(neigh, flags, ¬ify); + ext_learn_change = neigh_update_ext_learned(neigh, flags, ¬ify); if (!(new & NUD_VALID)) { neigh_del_timer(neigh); @@ -1376,7 +1381,7 @@ out: neigh_update_is_router(neigh, flags, ¬ify); write_unlock_bh(&neigh->lock); - if ((new ^ old) & NUD_PERMANENT) + if (((new ^ old) & NUD_PERMANENT) || ext_learn_change) neigh_update_gc_list(neigh); if (notify) @@ -1881,14 +1886,16 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, 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_create(tbl, dst, dev, - ndm->ndm_state & NUD_PERMANENT, - true); + 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; -- 2.30.2