segtree: check for overlapping elements at insertion

This speeds up element overlap checks quite a bit.

Fixes: https://bugzilla.netfilter.org/show_bug.cgi?id=1228
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/segtree.c b/src/segtree.c
index d2c4efaae2f0a4d1b799b99b85d4cf2347903ebe..1c23d4b81a0ddb08b1c780316fc04f179819dd6f 100644 (file)
--- a/src/segtree.c
+++ b/src/segtree.c
@@ -182,7 +182,8 @@ static bool segtree_debug(unsigned int debug_mask)
  * be ordered by descending interval size, meaning the new interval never
  * extends over more than two existing intervals.
  */
-static void ei_insert(struct seg_tree *tree, struct elementary_interval *new)
+static int ei_insert(struct list_head *msgs, struct seg_tree *tree,
+                    struct elementary_interval *new, bool merge)
 {
        struct elementary_interval *lei, *rei;
        mpz_t p;
@@ -199,6 +200,8 @@ static void ei_insert(struct seg_tree *tree, struct elementary_interval *new)
                pr_gmp_debug("insert: [%Zx %Zx]\n", new->left, new->right);
 
        if (lei != NULL && rei != NULL && lei == rei) {
+               if (!merge)
+                       goto err;
                /*
                 * The new interval is entirely contained in the same interval,
                 * split it into two parts:
@@ -220,6 +223,8 @@ static void ei_insert(struct seg_tree *tree, struct elementary_interval *new)
                ei_destroy(lei);
        } else {
                if (lei != NULL) {
+                       if (!merge)
+                               goto err;
                        /*
                         * Left endpoint is within lei, adjust it so we have:
                         *
@@ -238,6 +243,8 @@ static void ei_insert(struct seg_tree *tree, struct elementary_interval *new)
                        }
                }
                if (rei != NULL) {
+                       if (!merge)
+                               goto err;
                        /*
                         * Right endpoint is within rei, adjust it so we have:
                         *
@@ -260,6 +267,11 @@ static void ei_insert(struct seg_tree *tree, struct elementary_interval *new)
        __ei_insert(tree, new);
 
        mpz_clear(p);
+
+       return 0;
+err:
+       return expr_binary_error(msgs, lei->expr, new->expr,
+                                "conflicting intervals specified");
 }
 
 /*
@@ -292,18 +304,6 @@ static int interval_cmp(const void *p1, const void *p2)
        return ret;
 }
 
-static bool interval_conflict(const struct elementary_interval *e1,
-                             const struct elementary_interval *e2)
-{
-       if (mpz_cmp(e1->left, e2->left) <= 0 &&
-           mpz_cmp(e1->right, e2->left) >= 0 &&
-           mpz_cmp(e1->size, e2->size) == 0 &&
-           !expr_cmp(e1->expr->right, e2->expr->right))
-               return true;
-       else
-               return false;
-}
-
 static unsigned int expr_to_intervals(const struct expr *set,
                                      unsigned int keylen,
                                      struct elementary_interval **intervals)
@@ -375,23 +375,6 @@ static int set_overlap(struct list_head *msgs, const struct set *set,
        return 0;
 }
 
-static int intervals_overlap(struct list_head *msgs,
-                            struct elementary_interval **intervals,
-                            unsigned int keylen)
-{
-       unsigned int i, j;
-
-       for (i = 0; i < keylen - 1; i++) {
-               for (j = i + 1; j < keylen; j++) {
-                       if (interval_overlap(intervals[i], intervals[j]))
-                               return expr_error(msgs, intervals[j]->expr,
-                                       "interval overlaps with previous one");
-               }
-       }
-
-       return 0;
-}
-
 static int set_to_segtree(struct list_head *msgs, struct set *set,
                          struct expr *init, struct seg_tree *tree,
                          bool add, bool merge)
@@ -412,12 +395,6 @@ static int set_to_segtree(struct list_head *msgs, struct set *set,
 
        n = expr_to_intervals(init, tree->keylen, intervals);
 
-       if (add && !merge) {
-               err = intervals_overlap(msgs, intervals, n);
-               if (err < 0)
-                       return err;
-       }
-
        list_for_each_entry_safe(i, next, &init->expressions, list) {
                list_del(&i->list);
                expr_free(i);
@@ -432,14 +409,9 @@ static int set_to_segtree(struct list_head *msgs, struct set *set,
         * Insert elements into tree
         */
        for (n = 0; n < init->size; n++) {
-               if (init->set_flags & NFT_SET_MAP &&
-                   n < init->size - 1 &&
-                   interval_conflict(intervals[n], intervals[n+1]))
-                       return expr_binary_error(msgs,
-                                       intervals[n]->expr,
-                                       intervals[n+1]->expr,
-                                       "conflicting intervals specified");
-               ei_insert(tree, intervals[n]);
+               err = ei_insert(msgs, tree, intervals[n], merge);
+               if (err < 0)
+                       return err;
        }
 
        return 0;