netfilter: ipset: timeout can be modified for already added elements

When an element to a set with timeout added, one can change the timeout
by "readding" the element with the "-exist" flag. That means the timeout
value is reset to the specified one (or to the default from the set
specification if the "timeout n" option is not used). Example

ipset add foo 1.2.3.4 timeout 10
ipset add foo 1.2.3.4 timeout 600 -exist

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 62 insertions, 30 deletions

diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
index e9159e99fc4..a0290ffad35 100644
--- a/net/netfilter/ipset/ip_set_list_set.c
+++ b/net/netfilter/ipset/ip_set_list_set.c
@@ -109,15 +109,28 @@ list_set_kadt(struct ip_set *set, const struct sk_buff *skb,
 }
 
 static bool
-next_id_eq(const struct list_set *map, u32 i, ip_set_id_t id)
+id_eq(const struct list_set *map, u32 i, ip_set_id_t id)
 {
 	const struct set_elem *elem;
 
-	if (i + 1 < map->size) {
-		elem = list_set_elem(map, i + 1);
+	if (i < map->size) {
+		elem = list_set_elem(map, i);
+		return elem->id == id;
+	}
+
+	return 0;
+}
+
+static bool
+id_eq_timeout(const struct list_set *map, u32 i, ip_set_id_t id)
+{
+	const struct set_elem *elem;
+
+	if (i < map->size) {
+		elem = list_set_elem(map, i);
 		return !!(elem->id == id &&
 			  !(with_timeout(map->timeout) &&
-			    list_set_expired(map, i + 1)));
+			    list_set_expired(map, i)));
 	}
 
 	return 0;
@@ -190,12 +203,26 @@ list_set_del(struct list_set *map, u32 i)
 	return 0;
 }
 
+static void
+cleanup_entries(struct list_set *map)
+{
+	struct set_telem *e;
+	u32 i;
+
+	for (i = 0; i < map->size; i++) {
+		e = list_set_telem(map, i);
+		if (e->id != IPSET_INVALID_ID && list_set_expired(map, i))
+			list_set_del(map, i);
+	}
+}
+
 static int
 list_set_uadt(struct ip_set *set, struct nlattr *tb[],
 	      enum ipset_adt adt, u32 *lineno, u32 flags)
 {
 	struct list_set *map = set->data;
 	bool with_timeout = with_timeout(map->timeout);
+	bool flag_exist = flags & IPSET_FLAG_EXIST;
 	int before = 0;
 	u32 timeout = map->timeout;
 	ip_set_id_t id, refid = IPSET_INVALID_ID;
@@ -248,6 +275,8 @@ list_set_uadt(struct ip_set *set, struct nlattr *tb[],
 		}
 		timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
 	}
+	if (with_timeout && adt != IPSET_TEST)
+		cleanup_entries(map);
 
 	switch (adt) {
 	case IPSET_TEST:
@@ -259,22 +288,37 @@ list_set_uadt(struct ip_set *set, struct nlattr *tb[],
 			else if (with_timeout && list_set_expired(map, i))
 				continue;
 			else if (before > 0 && elem->id == id)
-				ret = next_id_eq(map, i, refid);
+				ret = id_eq_timeout(map, i + 1, refid);
 			else if (before < 0 && elem->id == refid)
-				ret = next_id_eq(map, i, id);
+				ret = id_eq_timeout(map, i + 1, id);
 			else if (before == 0 && elem->id == id)
 				ret = 1;
 		}
 		break;
 	case IPSET_ADD:
-		for (i = 0; i < map->size && !ret; i++) {
+		for (i = 0; i < map->size; i++) {
 			elem = list_set_elem(map, i);
-			if (elem->id == id &&
-			    !(with_timeout && list_set_expired(map, i)))
+			if (elem->id != id)
+				continue;
+			if (!(with_timeout && flag_exist)) {
 				ret = -IPSET_ERR_EXIST;
+				goto finish;
+			} else {
+				struct set_telem *e = list_set_telem(map, i);
+
+				if ((before > 1 &&
+				     !id_eq(map, i + 1, refid)) ||
+				    (before < 0 &&
+				     (i == 0 || !id_eq(map, i - 1, refid)))) {
+				     	ret = -IPSET_ERR_EXIST;
+				     	goto finish;
+				}
+				e->timeout = ip_set_timeout_set(timeout);
+				ip_set_put_byindex(id);
+				ret = 0;
+				goto finish;
+			}
 		}
-		if (ret == -IPSET_ERR_EXIST)
-			break;
 		ret = -IPSET_ERR_LIST_FULL;
 		for (i = 0; i < map->size && ret == -IPSET_ERR_LIST_FULL; i++) {
 			elem = list_set_elem(map, i);
@@ -283,9 +327,7 @@ list_set_uadt(struct ip_set *set, struct nlattr *tb[],
 					: list_set_add(map, i, id, timeout);
 			else if (elem->id != refid)
 				continue;
-			else if (with_timeout && list_set_expired(map, i))
-				ret = -IPSET_ERR_REF_EXIST;
-			else if (before)
+			else if (before > 0)
 				ret = list_set_add(map, i, id, timeout);
 			else if (i + 1 < map->size)
 				ret = list_set_add(map, i + 1, id, timeout);
@@ -299,16 +341,12 @@ list_set_uadt(struct ip_set *set, struct nlattr *tb[],
 				ret = before != 0 ? -IPSET_ERR_REF_EXIST
 						  : -IPSET_ERR_EXIST;
 				break;
-			} else if (with_timeout && list_set_expired(map, i))
-				continue;
-			else if (elem->id == id &&
-				 (before == 0 ||
-				  (before > 0 &&
-				   next_id_eq(map, i, refid))))
+			} else if (elem->id == id &&
+				   (before == 0 ||
+				    (before > 0 && id_eq(map, i + 1, refid))))
 				ret = list_set_del(map, i);
-			else if (before < 0 &&
-				 elem->id == refid &&
-				 next_id_eq(map, i, id))
+			else if (elem->id == refid &&
+				 before < 0 && id_eq(map, i + 1, id))
 				ret = list_set_del(map, i + 1);
 		}
 		break;
@@ -454,15 +492,9 @@ list_set_gc(unsigned long ul_set)
 {
 	struct ip_set *set = (struct ip_set *) ul_set;
 	struct list_set *map = set->data;
-	struct set_telem *e;
-	u32 i;
 
 	write_lock_bh(&set->lock);
-	for (i = 0; i < map->size; i++) {
-		e = list_set_telem(map, i);
-		if (e->id != IPSET_INVALID_ID && list_set_expired(map, i))
-			list_set_del(map, i);
-	}
+	cleanup_entries(map);
 	write_unlock_bh(&set->lock);
 
 	map->gc.expires = jiffies + IPSET_GC_PERIOD(map->timeout) * HZ;