diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index 7325bee7d14425..217225e13faf7d 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -38,10 +38,12 @@ static bool nft_rbtree_interval_start(const struct nft_rbtree_elem *rbe) return !nft_rbtree_interval_end(rbe); } -static bool nft_rbtree_equal(const struct nft_set *set, const void *this, - const struct nft_rbtree_elem *interval) +static int nft_rbtree_cmp(const struct nft_set *set, + const struct nft_rbtree_elem *e1, + const struct nft_rbtree_elem *e2) { - return memcmp(this, nft_set_ext_key(&interval->ext), set->klen) == 0; + return memcmp(nft_set_ext_key(&e1->ext), nft_set_ext_key(&e2->ext), + set->klen); } static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set, @@ -52,7 +54,6 @@ static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set const struct nft_rbtree_elem *rbe, *interval = NULL; u8 genmask = nft_genmask_cur(net); const struct rb_node *parent; - const void *this; int d; parent = rcu_dereference_raw(priv->root.rb_node); @@ -62,12 +63,11 @@ static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set rbe = rb_entry(parent, struct nft_rbtree_elem, node); - this = nft_set_ext_key(&rbe->ext); - d = memcmp(this, key, set->klen); + d = memcmp(nft_set_ext_key(&rbe->ext), key, set->klen); if (d < 0) { parent = rcu_dereference_raw(parent->rb_left); if (interval && - nft_rbtree_equal(set, this, interval) && + !nft_rbtree_cmp(set, rbe, interval) && nft_rbtree_interval_end(rbe) && nft_rbtree_interval_start(interval)) continue; @@ -215,154 +215,216 @@ static void *nft_rbtree_get(const struct net *net, const struct nft_set *set, return rbe; } +static int nft_rbtree_gc_elem(const struct nft_set *__set, + struct nft_rbtree *priv, + struct nft_rbtree_elem *rbe) +{ + struct nft_set *set = (struct nft_set *)__set; + struct rb_node *prev = rb_prev(&rbe->node); + struct nft_rbtree_elem *rbe_prev; + struct nft_set_gc_batch *gcb; + + gcb = nft_set_gc_batch_check(set, NULL, GFP_ATOMIC); + if (!gcb) + return -ENOMEM; + + /* search for expired end interval coming before this element. */ + do { + rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node); + if (nft_rbtree_interval_end(rbe_prev)) + break; + + prev = rb_prev(prev); + } while (prev != NULL); + + rb_erase(&rbe_prev->node, &priv->root); + rb_erase(&rbe->node, &priv->root); + atomic_sub(2, &set->nelems); + + nft_set_gc_batch_add(gcb, rbe); + nft_set_gc_batch_complete(gcb); + + return 0; +} + +static bool nft_rbtree_update_first(const struct nft_set *set, + struct nft_rbtree_elem *rbe, + struct rb_node *first) +{ + struct nft_rbtree_elem *first_elem; + + first_elem = rb_entry(first, struct nft_rbtree_elem, node); + /* this element is closest to where the new element is to be inserted: + * update the first element for the node list path. + */ + if (nft_rbtree_cmp(set, rbe, first_elem) < 0) + return true; + + return false; +} + static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set, struct nft_rbtree_elem *new, struct nft_set_ext **ext) { - bool overlap = false, dup_end_left = false, dup_end_right = false; + struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL; + struct rb_node *node, *parent, **p, *first = NULL; struct nft_rbtree *priv = nft_set_priv(set); u8 genmask = nft_genmask_next(net); - struct nft_rbtree_elem *rbe; - struct rb_node *parent, **p; - int d; + int d, err; - /* Detect overlaps as we descend the tree. Set the flag in these cases: - * - * a1. _ _ __>| ?_ _ __| (insert end before existing end) - * a2. _ _ ___| ?_ _ _>| (insert end after existing end) - * a3. _ _ ___? >|_ _ __| (insert start before existing end) - * - * and clear it later on, as we eventually reach the points indicated by - * '?' above, in the cases described below. We'll always meet these - * later, locally, due to tree ordering, and overlaps for the intervals - * that are the closest together are always evaluated last. - * - * b1. _ _ __>| !_ _ __| (insert end before existing start) - * b2. _ _ ___| !_ _ _>| (insert end after existing start) - * b3. _ _ ___! >|_ _ __| (insert start after existing end, as a leaf) - * '--' no nodes falling in this range - * b4. >|_ _ ! (insert start before existing start) - * - * Case a3. resolves to b3.: - * - if the inserted start element is the leftmost, because the '0' - * element in the tree serves as end element - * - otherwise, if an existing end is found immediately to the left. If - * there are existing nodes in between, we need to further descend the - * tree before we can conclude the new start isn't causing an overlap - * - * or to b4., which, preceded by a3., means we already traversed one or - * more existing intervals entirely, from the right. - * - * For a new, rightmost pair of elements, we'll hit cases b3. and b2., - * in that order. - * - * The flag is also cleared in two special cases: - * - * b5. |__ _ _!|<_ _ _ (insert start right before existing end) - * b6. |__ _ >|!__ _ _ (insert end right after existing start) - * - * which always happen as last step and imply that no further - * overlapping is possible. - * - * Another special case comes from the fact that start elements matching - * an already existing start element are allowed: insertion is not - * performed but we return -EEXIST in that case, and the error will be - * cleared by the caller if NLM_F_EXCL is not present in the request. - * This way, request for insertion of an exact overlap isn't reported as - * error to userspace if not desired. - * - * However, if the existing start matches a pre-existing start, but the - * end element doesn't match the corresponding pre-existing end element, - * we need to report a partial overlap. This is a local condition that - * can be noticed without need for a tracking flag, by checking for a - * local duplicated end for a corresponding start, from left and right, - * separately. + /* Descend the tree to search for an existing element greater than the + * key value to insert that is greater than the new element. This is the + * first element to walk the ordered elements to find possible overlap. */ - parent = NULL; p = &priv->root.rb_node; while (*p != NULL) { parent = *p; rbe = rb_entry(parent, struct nft_rbtree_elem, node); - d = memcmp(nft_set_ext_key(&rbe->ext), - nft_set_ext_key(&new->ext), - set->klen); + d = nft_rbtree_cmp(set, rbe, new); + if (d < 0) { p = &parent->rb_left; - - if (nft_rbtree_interval_start(new)) { - if (nft_rbtree_interval_end(rbe) && - nft_set_elem_active(&rbe->ext, genmask) && - !nft_set_elem_expired(&rbe->ext) && !*p) - overlap = false; - } else { - if (dup_end_left && !*p) - return -ENOTEMPTY; - - overlap = nft_rbtree_interval_end(rbe) && - nft_set_elem_active(&rbe->ext, - genmask) && - !nft_set_elem_expired(&rbe->ext); - - if (overlap) { - dup_end_right = true; - continue; - } - } } else if (d > 0) { - p = &parent->rb_right; + if (!first || + nft_rbtree_update_first(set, rbe, first)) + first = &rbe->node; - if (nft_rbtree_interval_end(new)) { - if (dup_end_right && !*p) - return -ENOTEMPTY; - - overlap = nft_rbtree_interval_end(rbe) && - nft_set_elem_active(&rbe->ext, - genmask) && - !nft_set_elem_expired(&rbe->ext); - - if (overlap) { - dup_end_left = true; - continue; - } - } else if (nft_set_elem_active(&rbe->ext, genmask) && - !nft_set_elem_expired(&rbe->ext)) { - overlap = nft_rbtree_interval_end(rbe); - } + p = &parent->rb_right; } else { - if (nft_rbtree_interval_end(rbe) && - nft_rbtree_interval_start(new)) { + if (nft_rbtree_interval_end(rbe)) p = &parent->rb_left; - - if (nft_set_elem_active(&rbe->ext, genmask) && - !nft_set_elem_expired(&rbe->ext)) - overlap = false; - } else if (nft_rbtree_interval_start(rbe) && - nft_rbtree_interval_end(new)) { + else p = &parent->rb_right; + } + } + + if (!first) + first = rb_first(&priv->root); + + /* Detect overlap by going through the list of valid tree nodes. + * Values stored in the tree are in reversed order, starting from + * highest to lowest value. + */ + for (node = first; node != NULL; node = rb_next(node)) { + rbe = rb_entry(node, struct nft_rbtree_elem, node); + + if (!nft_set_elem_active(&rbe->ext, genmask)) + continue; - if (nft_set_elem_active(&rbe->ext, genmask) && - !nft_set_elem_expired(&rbe->ext)) - overlap = false; - } else if (nft_set_elem_active(&rbe->ext, genmask) && - !nft_set_elem_expired(&rbe->ext)) { - *ext = &rbe->ext; - return -EEXIST; - } else { - overlap = false; - if (nft_rbtree_interval_end(rbe)) - p = &parent->rb_left; - else - p = &parent->rb_right; + /* perform garbage collection to avoid bogus overlap reports. */ + if (nft_set_elem_expired(&rbe->ext)) { + err = nft_rbtree_gc_elem(set, priv, rbe); + if (err < 0) + return err; + + continue; + } + + d = nft_rbtree_cmp(set, rbe, new); + if (d == 0) { + /* Matching end element: no need to look for an + * overlapping greater or equal element. + */ + if (nft_rbtree_interval_end(rbe)) { + rbe_le = rbe; + break; + } + + /* first element that is greater or equal to key value. */ + if (!rbe_ge) { + rbe_ge = rbe; + continue; + } + + /* this is a closer more or equal element, update it. */ + if (nft_rbtree_cmp(set, rbe_ge, new) != 0) { + rbe_ge = rbe; + continue; } + + /* element is equal to key value, make sure flags are + * the same, an existing more or equal start element + * must not be replaced by more or equal end element. + */ + if ((nft_rbtree_interval_start(new) && + nft_rbtree_interval_start(rbe_ge)) || + (nft_rbtree_interval_end(new) && + nft_rbtree_interval_end(rbe_ge))) { + rbe_ge = rbe; + continue; + } + } else if (d > 0) { + /* annotate element greater than the new element. */ + rbe_ge = rbe; + continue; + } else if (d < 0) { + /* annotate element less than the new element. */ + rbe_le = rbe; + break; } + } - dup_end_left = dup_end_right = false; + /* - new start element matching existing start element: full overlap + * reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given. + */ + if (rbe_ge && !nft_rbtree_cmp(set, new, rbe_ge) && + nft_rbtree_interval_start(rbe_ge) == nft_rbtree_interval_start(new)) { + *ext = &rbe_ge->ext; + return -EEXIST; + } + + /* - new end element matching existing end element: full overlap + * reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given. + */ + if (rbe_le && !nft_rbtree_cmp(set, new, rbe_le) && + nft_rbtree_interval_end(rbe_le) == nft_rbtree_interval_end(new)) { + *ext = &rbe_le->ext; + return -EEXIST; } - if (overlap) + /* - new start element with existing closest, less or equal key value + * being a start element: partial overlap, reported as -ENOTEMPTY. + * Anonymous sets allow for two consecutive start element since they + * are constant, skip them to avoid bogus overlap reports. + */ + if (!nft_set_is_anonymous(set) && rbe_le && + nft_rbtree_interval_start(rbe_le) && nft_rbtree_interval_start(new)) + return -ENOTEMPTY; + + /* - new end element with existing closest, less or equal key value + * being a end element: partial overlap, reported as -ENOTEMPTY. + */ + if (rbe_le && + nft_rbtree_interval_end(rbe_le) && nft_rbtree_interval_end(new)) return -ENOTEMPTY; + /* - new end element with existing closest, greater or equal key value + * being an end element: partial overlap, reported as -ENOTEMPTY + */ + if (rbe_ge && + nft_rbtree_interval_end(rbe_ge) && nft_rbtree_interval_end(new)) + return -ENOTEMPTY; + + /* Accepted element: pick insertion point depending on key value */ + parent = NULL; + p = &priv->root.rb_node; + while (*p != NULL) { + parent = *p; + rbe = rb_entry(parent, struct nft_rbtree_elem, node); + d = nft_rbtree_cmp(set, rbe, new); + + if (d < 0) + p = &parent->rb_left; + else if (d > 0) + p = &parent->rb_right; + else if (nft_rbtree_interval_end(rbe)) + p = &parent->rb_left; + else + p = &parent->rb_right; + } + rb_link_node_rcu(&new->node, parent, p); rb_insert_color(&new->node, &priv->root); return 0;