From e701001e7cbe88cdc937037f6f398669eef7e7ff Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 12 Apr 2016 23:50:37 +0200 Subject: [PATCH] netfilter: nft_rbtree: allow adjacent intervals with dynamic updates This patch fixes dynamic element updates for adjacent intervals in the rb-tree representation. Since elements are sorted in the rb-tree, in case of adjacent nodes with the same key, the assumption is that an interval end node must be placed before an interval opening. In tree lookup operations, the idea is to search for the closer element that is smaller than the one we're searching for. Given that we'll have two possible matchings, we have to take the opening interval in case of adjacent nodes. Range merges are not trivial with the current representation, specifically we have to check if node extensions are equal and make sure we keep the existing internal states around. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_rbtree.c | 40 +++++++++++++++++++++++++++++++++----- 1 file changed, 35 insertions(+), 5 deletions(-) diff --git a/net/netfilter/nft_rbtree.c b/net/netfilter/nft_rbtree.c index 29f2ab88d787..f762094af7c1 100644 --- a/net/netfilter/nft_rbtree.c +++ b/net/netfilter/nft_rbtree.c @@ -35,6 +35,12 @@ static bool nft_rbtree_interval_end(const struct nft_rbtree_elem *rbe) (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END); } +static bool nft_rbtree_equal(const struct nft_set *set, const void *this, + const struct nft_rbtree_elem *interval) +{ + return memcmp(this, nft_set_ext_key(&interval->ext), set->klen) == 0; +} + static bool nft_rbtree_lookup(const struct nft_set *set, const u32 *key, const struct nft_set_ext **ext) { @@ -42,6 +48,7 @@ static bool nft_rbtree_lookup(const struct nft_set *set, const u32 *key, const struct nft_rbtree_elem *rbe, *interval = NULL; const struct rb_node *parent; u8 genmask = nft_genmask_cur(read_pnet(&set->pnet)); + const void *this; int d; spin_lock_bh(&nft_rbtree_lock); @@ -49,9 +56,16 @@ static bool nft_rbtree_lookup(const struct nft_set *set, const u32 *key, while (parent != NULL) { rbe = rb_entry(parent, struct nft_rbtree_elem, node); - d = memcmp(nft_set_ext_key(&rbe->ext), key, set->klen); + this = nft_set_ext_key(&rbe->ext); + d = memcmp(this, key, set->klen); if (d < 0) { parent = parent->rb_left; + /* In case of adjacent ranges, we always see the high + * part of the range in first place, before the low one. + * So don't update interval if the keys are equal. + */ + if (interval && nft_rbtree_equal(set, this, interval)) + continue; interval = rbe; } else if (d > 0) parent = parent->rb_right; @@ -101,9 +115,16 @@ static int __nft_rbtree_insert(const struct nft_set *set, else if (d > 0) p = &parent->rb_right; else { - if (nft_set_elem_active(&rbe->ext, genmask)) - return -EEXIST; - p = &parent->rb_left; + if (nft_set_elem_active(&rbe->ext, genmask)) { + if (nft_rbtree_interval_end(rbe) && + !nft_rbtree_interval_end(new)) + p = &parent->rb_left; + else if (!nft_rbtree_interval_end(rbe) && + nft_rbtree_interval_end(new)) + p = &parent->rb_right; + else + return -EEXIST; + } } } rb_link_node(&new->node, parent, p); @@ -148,7 +169,7 @@ static void *nft_rbtree_deactivate(const struct nft_set *set, { const struct nft_rbtree *priv = nft_set_priv(set); const struct rb_node *parent = priv->root.rb_node; - struct nft_rbtree_elem *rbe; + struct nft_rbtree_elem *rbe, *this = elem->priv; u8 genmask = nft_genmask_cur(read_pnet(&set->pnet)); int d; @@ -166,6 +187,15 @@ static void *nft_rbtree_deactivate(const struct nft_set *set, parent = parent->rb_left; continue; } + if (nft_rbtree_interval_end(rbe) && + !nft_rbtree_interval_end(this)) { + parent = parent->rb_left; + continue; + } else if (!nft_rbtree_interval_end(rbe) && + nft_rbtree_interval_end(this)) { + parent = parent->rb_right; + continue; + } nft_set_elem_change_active(set, &rbe->ext); return rbe; } -- GitLab