@@ -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;