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Date: Sat, 20 Oct 2018 11:43:17 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 10/10] Revert "netfilter: xt_quota: fix the behavior of xt_quota module"
This reverts commit e9837e55b0200da544a095a1fca36efd7fd3ba30.
When talking to Maze and Chenbo, we agreed to keep this back by now
due to problems in the ruleset listing path with 32-bit arches.
Signed-off-by: Maciej Żenczykowski <maze@...gle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/uapi/linux/netfilter/xt_quota.h | 8 ++---
net/netfilter/xt_quota.c | 55 ++++++++++++++++++++-------------
2 files changed, 36 insertions(+), 27 deletions(-)
diff --git a/include/uapi/linux/netfilter/xt_quota.h b/include/uapi/linux/netfilter/xt_quota.h
index d72fd52adbba..f3ba5d9e58b6 100644
--- a/include/uapi/linux/netfilter/xt_quota.h
+++ b/include/uapi/linux/netfilter/xt_quota.h
@@ -15,11 +15,9 @@ struct xt_quota_info {
__u32 flags;
__u32 pad;
__aligned_u64 quota;
-#ifdef __KERNEL__
- atomic64_t counter;
-#else
- __aligned_u64 remain;
-#endif
+
+ /* Used internally by the kernel */
+ struct xt_quota_priv *master;
};
#endif /* _XT_QUOTA_H */
diff --git a/net/netfilter/xt_quota.c b/net/netfilter/xt_quota.c
index fceae245eb03..10d61a6eed71 100644
--- a/net/netfilter/xt_quota.c
+++ b/net/netfilter/xt_quota.c
@@ -11,6 +11,11 @@
#include <linux/netfilter/xt_quota.h>
#include <linux/module.h>
+struct xt_quota_priv {
+ spinlock_t lock;
+ uint64_t quota;
+};
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sam Johnston <samj@...j.net>");
MODULE_DESCRIPTION("Xtables: countdown quota match");
@@ -21,48 +26,54 @@ static bool
quota_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
struct xt_quota_info *q = (void *)par->matchinfo;
- u64 current_count = atomic64_read(&q->counter);
+ struct xt_quota_priv *priv = q->master;
bool ret = q->flags & XT_QUOTA_INVERT;
- u64 old_count, new_count;
-
- do {
- if (current_count == 1)
- return ret;
- if (current_count <= skb->len) {
- atomic64_set(&q->counter, 1);
- return ret;
- }
- old_count = current_count;
- new_count = current_count - skb->len;
- current_count = atomic64_cmpxchg(&q->counter, old_count,
- new_count);
- } while (current_count != old_count);
- return !ret;
+
+ spin_lock_bh(&priv->lock);
+ if (priv->quota >= skb->len) {
+ priv->quota -= skb->len;
+ ret = !ret;
+ } else {
+ /* we do not allow even small packets from now on */
+ priv->quota = 0;
+ }
+ spin_unlock_bh(&priv->lock);
+
+ return ret;
}
static int quota_mt_check(const struct xt_mtchk_param *par)
{
struct xt_quota_info *q = par->matchinfo;
- BUILD_BUG_ON(sizeof(atomic64_t) != sizeof(__u64));
-
if (q->flags & ~XT_QUOTA_MASK)
return -EINVAL;
- if (atomic64_read(&q->counter) > q->quota + 1)
- return -ERANGE;
- if (atomic64_read(&q->counter) == 0)
- atomic64_set(&q->counter, q->quota + 1);
+ q->master = kmalloc(sizeof(*q->master), GFP_KERNEL);
+ if (q->master == NULL)
+ return -ENOMEM;
+
+ spin_lock_init(&q->master->lock);
+ q->master->quota = q->quota;
return 0;
}
+static void quota_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_quota_info *q = par->matchinfo;
+
+ kfree(q->master);
+}
+
static struct xt_match quota_mt_reg __read_mostly = {
.name = "quota",
.revision = 0,
.family = NFPROTO_UNSPEC,
.match = quota_mt,
.checkentry = quota_mt_check,
+ .destroy = quota_mt_destroy,
.matchsize = sizeof(struct xt_quota_info),
+ .usersize = offsetof(struct xt_quota_info, master),
.me = THIS_MODULE,
};
--
2.11.0
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