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-rw-r--r--libiptc/libiptc.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/libiptc/libiptc.c b/libiptc/libiptc.c
index 218ff039..dfa2d1f0 100644
--- a/libiptc/libiptc.c
+++ b/libiptc/libiptc.c
@@ -1,4 +1,4 @@
-/* Library which manipulates firewall rules. Version $Revision: 1.56 $ */
+/* Library which manipulates firewall rules. Version $Revision$ */
/* Architecture of firewall rules is as follows:
*
@@ -1319,11 +1319,18 @@ TC_REPLACE_ENTRY(const IPT_CHAINLABEL chain,
return 0;
}
- if (!(old = iptcc_get_rule_num(c, rulenum + 1))) {
+ if (rulenum >= c->num_rules) {
errno = E2BIG;
return 0;
}
+ /* Take advantage of the double linked list if possible. */
+ if (rulenum + 1 <= c->num_rules/2) {
+ old = iptcc_get_rule_num(c, rulenum + 1);
+ } else {
+ old = iptcc_get_rule_num_reverse(c, c->num_rules - rulenum);
+ }
+
if (!(r = iptcc_alloc_rule(c, e->next_offset))) {
errno = ENOMEM;
return 0;